| Retrieval (variant) CAPP systems | This is an older CAPP system based on Group Technology and parts classification & coding. Standard process plans are stored in computer files with each part code number
- Plans are based on current part routing
- For each new part, the standard plan is edited
- If file doesn't exist, can search a similar code name and edit it to become the standard plan for the new part
- Final step is the process plan formatter which may call on other application programs
e.g. design cutting conditions, computing cost estimates |
| Group Technology | - A manufacturing philosophy where similar parts are grouped together to take advantage of similarities in design and production
- Similar parts are arranged into part families |
| Generative CAPP systems (newer) | - Newer CAPP system
- Process plans are created using rules a human may follow.
- In fully generative CAPP systems, process sequences can be planned without any human assistance or predefined standard plans
- Expert system required to build generative CAPP systems |
| Components of an Expert system for a generative CAPP system | Knowledge base
- Technical knowledge of manufacturing and logic
Computer-compatible part description
- Description of product needed for the process sequence
Inference engine
- Algorithm that applies planning logic and process knowledge located in the knowledge base |
| Dynamic, generative CAPP | - Still developing CAPP system
- Artificial intelligence is used to produce process plan
- Considers plant and machine capacities, tool availability, work centre, equipment loads and status
- Smooth blending between process and production |
| Benefits of CAPP | - Process rationalisation and standardisation
- Increased productivity
- Reduced lead times to prepare process plans
- Improved legibility over manually written route sheets
- Can be integrated with other applications
(e.g. design cutting conditions, computing cost estimates)
- CAPP is good for discrete parts with significant numbers of products and steps |
