Transcript Tool Design - Hong Kong University of Science and Technology

MECH152-L25 - 1
Tool Design
MECH152-L25 - 2
Types of Tools
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Material Cutting Tools
Workholding Devices
Pressworking Tools
Bending, Forming
and Drawing Dies
http://www.youtube.com/watch?v=gkHbRVUvFgw&feature=channel_page
Tool Design for Inspection and Gaging
Tool Design for Joining Process
Tooling for Casting
http://www.youtube.com/watch?v=z4D76vMqwD4&feature=channel_page
http://www.youtube.com/watch?v=3ciyG_hidhE&feature=channel_page
http://www.youtube.com/watch?v=4Pw_tcgIiTQ&feature=channel_page
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General Considerations
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Safety and Ergonomics
Tool Materials
Heat Treatment
Surface Roughness and Finish
Tolerances and Fits
Tooling Economics
Material Handling
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Safety and Ergonomics (I)
• Safety should be built into the design
with due respect to legal requirements
• Sufficient clamping and rigidity of the
tool design is necessary
• Guards should be introduced to
movable parts of the machine
• Limit switches to protect workers and
product against moving parts
• Electrical equipment should be properly
grounded
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Safety and Ergonomics (II)
• Exhaust system for air polluting system
• All adjustments and clamping should be
easily accessible
• Quick release or emergency braking
mechanism may be needed for special
cases
• Prevent severe burns or eye injury for
welding or thermal process
• Provision for handling pressurized and
toxic equipment
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Tool Materials (I)
• Tool steels (principal materials)
– Tool and Die Steel (typical hardness RC40~60)
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W, Water-Hardening Tool-Steels
O, Oil-Hardening Tool-Steels
A, Air-Hardening Medium Alloy Die-Steels
D, High-Carbon High-Chromium Die Steels
S, Shock-Resisting Tool-Steels
H, Hot-Work Die Steels
P, Low-Carbon Mold Steels
T and M, Tungsten and Molydenum High-Speed Steels
L, Low-Alloy Tool-Steels
F, Carbon-Tungsten Finishing Steels
(http://www.efunda.com/materials/alloys/tool_steels/tool.cfm)
• Cast Iron
• Stainless Steel
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Tool Materials (II)
• Non-ferrous materials - limited
productions only (Aluminum,
Magnesium, Zinc, Lead, Beryllium,
Bismuth)
• Composite materials – soft tools for
limited run
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Workholding Devices
Workholding Devices – All devices that
hold, grip, or chuck a workpiece in a
prescribed manner of firmness and
location, to perform on it a
manufacturing operation.
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Fixture & Jig
Fixture:
- Hold and accurately position a
workpiece http://www.youtube.com/watch?v=ujKyRrf-Z1M&feature=channel_page
Jig:
- Also be used to hold and position a
workpiece.
- Provides some means for guiding
the cutting tool
http://www.youtube.com/watch?v=2ikkuZe0zQU&feature=channel_page
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Examples - I
• High Rise Clamps
http://www.carrlane.com/Catalog/index.cfm
High-Rise Clamps
can be stacked on
Narrow Riser
Blocks and Spacer
Blocks to reach tall
workpieces
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Examples II
http://www.steelsmith.com/
• Swing Clamp
Please refer to the
price list also!
ARM: MODULAR IRON PER ASTM
A536 GRADE 65-45-12, ZINC PLATED
CLEAR CHROMATE
ALL OTHER PARTS: MILD STEEL,
BLACK OXIDE FINISH
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Examples III
Automatic
Reversible Cam
Action Workholding
Assemblies
http://www.youtube.com/watch?v=vrrjLYn-6WY
Methods of Location
3-2-1 Principle
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http://www.youtube.com/watch?v=wTs_IaD0JWU&feature=PlayList&p=3AFB507B668AF162&index=35
- A workpiece will be completely confined
when banked against:
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3 points in one plane
2 points in another plane
1 point in a third plane
If the planes are perpendicular to each
other
- Buttons should be as far apart as
possible
- Greater spread, Less alignment error
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Methods of Location I
12 degrees of
freedom
3 pins arrest
5 dof
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Methods of Location II
5 pins arrest
8 dof
Horizontal
workpiece
6 pins arrest
9 dof
Vertical
workpiece
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Methods of Location III
Radical location
with internal pins
or plug
Radical location
by external pins
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Methods of Location IV
7 dof
arrested by
V locator
with stop
pin
Workholder with
multiple V locators
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Tool Forces I
Pin-type drill
fixture resisting
torque and thrust
Tapping
fixture
resisting
torque and
thrust
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Tool Forces II
Workholder for
broaching operation
Cutting
Forces
resisted by
solid jaw
of vise
Cutting force resisted
only by friction
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Tool Forces III
Mechanical
methods of
transmitting and
multiplying force
(A) Screw
(B) Cam
(C) Wedge
(D) Toggle link
(E) Lever
(F) Combined
screw and wedge
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Clamping Forces I
Fixture
components
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Clamping and Support
http://www.youtube.com/watch?v=l-V4mplHjZ8
Clamping and
support of large
workpiece
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Fixture Components
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Fixture Components
Toggle clamp
http://www.youtube.com/watch?v=H4r8hUyZMUY
http://www.youtube.com/watch?v=ZefYGTMKRUw
http://www.youtube.com/watch?v=nheuik2YHkI
Quick-acting
screw
Jigs and Fixture Design
Principles
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• Review the workpiece to determine the
manufacturing processes
• Decide on the number of setups
• Determine for each setup
– Reference surface
– Workpiece location
– Workpiece clamping and rigidity
– Ergonomics and safety
http://www.youtube.com/watch?v=ujKyRrf-Z1M&feature=channel
Fixture for Rectangular
Components
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Clamping action
• Location and holding for flat surface
• Base plate - reference surface for setup
• Clamp – quick action cam-based clamp
Fixture for Rectangular
Components
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• Hydraulic clamp for larger clamping force
• Swing clamp http://www.youtube.com/watch?v=1RMqoQlZ-2c
http://www.youtube.com/watch?v=jkAINXgZaCk
Fixture for Rectangular
Components
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Magnetic chuck
http://www.youtube.com/watch?v=WzawhEUBLL8&feature=PlayList&p=CAC636741CCDCCB0&playnext=1&playnext_from=PL&index=4
http://www.youtube.com/watch?v=S-xKCAHpU-4&feature=PlayList&p=CAC636741CCDCCB0&playnext=1&playnext_from=PL&index=6
http://www.youtube.com/watch?v=8pabjZp4D2Y
Vacuum
chuck
http://www.youtube.com/watch?v=xr3lfAvQuJs&feature=related
http://www.youtube.com/watch?v=2jcQZ5W4ED4
Fixture for Rectangular
Components
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Electrostatic chuck
Vacuum chuck
Fixture for Circular
Components
Round workpiece
held with strap clamp
and T bolts
Fixture for straddle
milling connecting rod
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Fixture for Circular
Components
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Workpiece held in a 4jaw chuck for a boring
operation
http://www.youtube.com/watch?v=npJfKhkS0QE
Nut arbor
Fixture for Circular
Components
V block
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Drill jig – V block, quickacting clamp, and drill
bushing combination
http://www.youtube.com/watch?v=QFH2kUorn88
Fixture for Circular
Components
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Internal and
endwise
chucking
Between centers
and combination
with chucking
Fixture for Circular
Components
Solid mandrel
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Roll lock type
expanding mandrel
Fixture for Circular
Components
Split busing and
split collet
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Axial location
by collet
Collet with stopper
http://www.youtube.com/watch?v=bJIIeN4rg3E
Fixture for Circular
Components
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Collet with immediate
bushing to eliminate
axial shift
Collet for internal chucking
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Rigid and Elastic Workholding
Rigid workholding
Elastic and spring workholding
Rigid/hydraulic workholding
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Accuracy of Work Location
Accuracy of work location
Concentricity of workpiece
by collet
Workholders for Irregular
Workpiece
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Pump-type jigs
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Workholding Selection
Workpiece rotation
Tool rotation
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Workholding Selection
Steady to
reduce
workpiece
vibration
Minimizing cutting
force by applying
holding force close to
point of tool application
http://www.youtube.com/watch?v=2o74aR0JL1k
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Cutter Setup
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Box-Type Drill Jigs
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Milling Fixture
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Milling Fixture
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Milling Fixture
Indexing fixture
http://www.youtube.com/watch?v=JkftVHaMQSs
Key slot milling
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Milling Fixture