COLT Design Manual for Cold Forging Dies Case study: starter pinions (1) Case study: Cold forging of starter pinions for automotive starters Cold forged.
Download ReportTranscript COLT Design Manual for Cold Forging Dies Case study: starter pinions (1) Case study: Cold forging of starter pinions for automotive starters Cold forged.
Slide 1
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 2
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 3
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 4
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 5
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 6
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 7
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 8
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 9
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 10
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 11
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 2
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 3
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 4
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 5
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 6
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 7
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 8
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 9
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 10
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 11
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (1)
Case study: Cold forging of starter pinions
for automotive starters
Cold forged starter pinions
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (2)
Typical failure mode in the lower die insert
Vertical and horizontal
fatigue cracks in the
lower die insert
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (3)
Tooling system for improved radial and axial prestressing
(STRECON® E+ Axi-Fit)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (4)
FE analysis of the tooling system
with regard to the vertical crack initiation
2D FE model of the cross-section with the gear profile
Assumed process pressure distribution
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (5)
Stress response in the prestressed condition
Because of its higher stiffness, prestressing by the STRECON® E+ leads
- despite the lower nominal interference - to a similar prestress level
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (6)
Stress response in the condition at max. process load
Prestressing by the STRECON® E + reduces the
tensile stress in the fillets at maximum process load
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (7)
FE analysis of the tooling system
with regard to the horizontal crack initiation
Contact area
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (8)
Contact stresses between upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the maximum contact stress
becomes higher and gets closer to the inner bore of the die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (9)
Axial stresses in the upper and lower die insert
in the prestressed condition
By reducing the plane contact area, the axial prestress in the
shoulder (where the cracks actually occur) is increased
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (10)
Axial prestress during assembly
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: starter pinions (11)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended tooling system:
• STRECON® E+ Axi-Fit
provides high stiffness
and combines improved
radial and axial prestressing
Result:
• Die life for starter pinion dies
improved by factor 2-3
(depending on the type
of starter pinion)
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.