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5.08 - Small Process Plant


Traditional Approach - buy ‘super machines’ and keep them busy. There is little emphasis on natural groupings, of component mix & demand frequency.

Japanese Approach - make or buy SMALL machines. Add more as needed. Only use CNC machines where product variety & batch size merit their use.


The Traditional European View - Complex technology solves our problems.

The Japanese View - Small cheap machines allow:-

  • Less emphasis on machine utilisation (recognising that high utilisation can lead to long lead times)
  • Quick and easy end-user maintenance
  • Purchase of duplicate machines - set up ready for changeovers
  • Multi-purpose U-Shaped cells
  • Internal machine tool development (which generates know how for changeover reduction times, etc)
  • Flexibility

Example: Heat Treatment / Processing

  • Small ovens strategically distributed instead of big ‘Super Ovens’
  • Small wash tanks strategically distributed in factory instead of large centralised tanks

Project Scale Categorisation

  • Reduced lead times (no batching up to send to heat treatment), reduced queues.
  • Matches the needs of Kanban Production Systems (i.e. simpler control system).
  • Reduces complexity (need for ‘gateways’, etc reduced)
  • Enhances ‘ownership’ of problems.

Machinery Choice




Up and Down Arrow

2x capital cost at each stage

Dedicated specialised machinery

  • Suitable for a low variety of runners
  • Very short cycle time (production rate high)
  • One worker can operate a number of machines easily
  • Ideal for multi-process cells
  • Easy maintenance
  • Not suitable for small lot production
  • Low flexibility

Semi-dedicated, semi-flexible Machinery

Suitable for repeaters:
Advantages and disadvantages lie between those outlined above and below.


Expensive, highly flexible machinery

  • Suitable for strangers and a variety of runners.
  • Effective for smaller batches
  • Small lot production of a variety of products
  • Highly flexibility of production
  • Longer cycle time
  • CNC skills required
  • Expensive
  • Specialist support (overhead) needed for maintenance and programming
  • Complex fixtures and tooling, plus maintenance difficulties can lead to process incapability


  • Cycle time versus flexibility
  • Flexibility versus capital cost
    • Influenced by ability to modify for quick changeover