Process Selection CAPP

1
Process Selection - CAPP
Computer Aided Process Planning (CAPP)
Automate the manual planning process
Variant

• Standard process plans for each part family are
  stored and retrieved when required

Generative

• Process plans are generated automatically for
  new components
• Product structure
• Cost

2
Process Selection Route Sheet
Processes, Equipment, and Raw Material

• Component Name and number
• Operation description and number
• Equipment requirements
• Unit times
• Raw material requirements

Process Identification
Process Selection
What is next?
3
Process Sequencing
How is the product assembled?
Assembly Chart

• Finished Product
• Trace the product disassembly to its basic
  components

Operation Process Chart

• superimpose the route sheets on assembly chart
• overview of the flow within the facility

4
Schedule Design

• How much to produce?
• When to produce?

Lot sizing
Production scheduling
Market forecasts

• How long production will continue?

Impact on

• storage equipment
• MH equipment
• building size
• storage policy

• machine selection
• number of machines
• number of shifts
• number of employees
• space requirements
• personnel requirements

5
Scrap Estimates
How many (annual volume)?
Market estimate
Number of units scheduled through production ?
Market estimate scrap
Pk of scrap produced in operation k Ok
desired output of non-defective product from
operation k Ik production input to operation k
Ok Ik PkIk
Ok Ik (1 Pk)
Ik Ok /(1 Pk)
I1 On /(1 P1) (1 P2) (1 Pn)
6
Equipment Fractions
What is equipment fraction?
The quantity of equipment required for an
operation
Equipment fraction
Total time required to perform an operation
standard time for the operation number of
times performed

• Efficiency
• Reliability

Question about
7
Equipment Fractions (cont.)
F number of machines required per shift S
standard time (minutes) per unit produced Q
number of units to be produced per shift E
actual performance, expressed as a of standard
time H amount of time (minutes) available per
machine R reliability of the machine, expressed
as up-time
F SQ/EHR
8
Equipment Requirements
Pij desired production rate for product i on
machine j (pieces/production period) Tij
production time for product i on machine j
(hours/piece) Hij number of hours in the
production period available for the production of
product i on machine j Mj number of machines of
type j required per production period n number
of products
9
Equipment Requirements - Example

• Six different products are being produced
• Same type of machine is used for processing
  these products
• Standard number of pieces to be produced/hour
  (1/Tij) for each product
• Desired production rate (Pij)
• Number of hours in a month (Hij 150)