Process Selection & Capacity Planning
Chapter 5
Stevenson
First decision
Make or buy
Available capacity
Quality requirements
Nature of demand
Cost
Process selection & systems
Input resources
Forecasting
Product and service design
Output requirements
Capacity planning
Facilities and equipment
Layout
Work design
Process types
Continuous
Repetitive/assembly
Intermittent/batch
Job shops
Projects
Process & Product matrix
Process selection depends on
Volume requirements
Product variety
Equipment flexibility
Life cycle - stage
Variety, Flexibility, Volume
Product/Process Life Cycle Matrix
Automation
CAD/CAM
CNC
Flexible manufacturing systems
CIM
Steps to automating
Form cells to make family of parts
Implement a rapid exchange of tooling and dies
Integrate quality control
Integrate preventive maintenance
Level and balance final assembly
Steps to automating
Integrate production control - link the cells
Reduce WIP
Extend improvements to vendors
Automate and robotize - solve problems
Computerize to link the cells
Capacity planning
Capacity - Upper limit a unit can handle
Basic questions
What kind of capacity is needed?
How much is needed?
When is it needed?
Capacity
Design capacity
Effective capacity
= (Design - reality)
Actual output
Efficiency & utilization
Efficiency = Actual/Effective
Utilization = Actual/Design
Effective capacity factors
Facilities
Products or services
Processes
Human considerations
Operations
External forces
Capacity Alternatives
Design flexibility into systems
Take a "big picture" approach to capacity changes
Prepare to deal with capacity "chunks"
Attempt to smooth out capacity requirements
Identify the optimal operating level
Capacity Alternatives
Capacity Alternatives
Reflect on this:
Stevenson - p.193 "Ideally, capacity and demand requirements will be matched."
Goldratt - p.138 "…trying to level capacity with demand to minimize expenses has really screwed us up."
Revenue-Volume Relationship
Cost-Volume Relationship
Break-even Point