Transcript Manufacturing Planning & Control System

Manufacturing Planning &
Control System
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Major Tasks
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restate business objectives in operations
management terms
ensure feasibility of plans
identify gaps in current resources
help formulate connective action-Suppliers
prioritize activities - scheduling
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facilitate feedback
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Keys to MPC
Manufacturing Planning and Control System
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A complete, current and accurate database
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one set of records
high emphasis on data accuracy
quick correction of error in db
accessible to all who need data
System discipline
Transparent logic
Production Plan
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First step in the planning process
One of three high level plans
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Business Plan
Sales Plan
Production Plan
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differences between sales plan and production plan is the
inventory plan
Long term perspective
Stated in aggregate units
Issues Considered
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Capacity management
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level
chase
mixed
Requires coordination with marketing
Demand management
Master Production Schedule
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Definition: document that defines the
specific goods that specific shops will
produce in definite quantities at definite
times over a short-term horizon in
accordance with the aggregate plan
The MPS represents an agreement
between marketing and manufacturing
Master Production Schedule
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A detailed disaggregation of production plan
Time-phased statement of how over the planning
horizon resources will be used to meet agreed-to
commitments
Tends to be:
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short time horizon
more detailed product information (BoMs)
more concern over capacity
corporate plan
quasi-contract
updated regularly
What is the MPS?
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Plan showing availability
Build schedule
Stated in BoM terms
MPS Problems
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Overloaded
Front End Loaded
Unstable
Incomplete
Short Horizon
Wishlist
Stability in MPS
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Balance need of OM for stability and marketing for
change.
Why is stability important?
How introduced?
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timing fencing
time fences denote different reaction to changes and willingness
to accommodate change
recognizes increasing cost of change as we near current time
Different zones
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types of changes
who approves
who bears cost
MPS Principles
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The MPS must be in concert with the
production plan
The MPS must drive the entire materials
management system
Include all known requirements in the
preparation of the MPS and the FAX
Minimize the number of items needed to
adequately express the MPS and the FAS
Key Terms from Ch. 14
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MPS – Master Production Schedule
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(Aggregate) Production Plan
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Short term
families
BOM – Bill of Material
Routing file
Material Requirements
Planning
MRP and Dependent Demand
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Dependent Demand
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demand that is derived
consists of WIP + Raw materials
concept of parent/component
independent demand in MPS
Problem with Dependent Demand
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information generated
challenge - generating 100% CSL
past approach - s,Q
new approach - MRP
Prior to MRP
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Up to 1970s, extensive use of s,Q models
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why? Simple to use, limited information
requirements, “optional”
Why move to MRP?
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problems with s,Q models
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high levels of inventory
high stockouts
poor customer services
“Order launch & Expedite”
Why MRP? (2)
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S,Q ignored BoM information
Item
A
B (comp)
C
D
OQ
300
250
200
250
OH
0
0
0
0
A uses 1 B; B uses 1 C; C uses 1 D
What happens if we receive an order for 50 units
of A?
Other Factors
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Major changes
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high cost of inventory
increased availability of more powerful
computers
decreasing cost of computers
MRP now supported by extensive body
of software
MRP Elements
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Gross Requirements
On-Hand Inventory
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Allocations
Scheduled Receipts
Net Requirements
Planned Order Releases
Time-phasing
Parent/Component
MRP Elements
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Planning factors
System nervousness
Firm planning
Explosion
Time buckets
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Action bucket
Rolling the Schedule
Net Change vs. Regenerative MRP
Advantages of MRP
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Forward looking when planning (visibility)
Useful simulator
Provides valid, credible priorities
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priorities reflect actual needs, not implied needs.
Provides mangers with control over the
execution system
Forms basis for building credible, valid formal
system
Limitations of MRP
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only looks at materials, ignores
capacity, shop floor conditions
requires user discipline
requires accurate information/data
requires valid MPS
not appropriate for all areas
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high volume production
projects
Types of MRP Systems
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MRP
Closed Loop MRP
MRP II
Distribution Requirements Planning
DRP II
Enterprise Requirement Planning
The Curve
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42-50
37-41
31-36
26-30
>26
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Mean 2.75
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A
B
C
D
F
23
37
30
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