Fixed position and cellular layout notes

(a) Fixed position layout

In this layout the product stays in one place because it is too large or heavy to move, and the workers, machines and materials are brought to it.

• Examples: shipbuilding, aircraft assembly, construction of bridges, dams and buildings, large turbines.
• Advantages: no movement of the heavy product, flexible for design changes, work can be assigned to skilled teams, suitable for one-off projects.
• Disadvantages: movement of materials and equipment is high, the space around the product may be crowded, equipment utilisation is low, and skilled labour and good scheduling are needed.

(b) Group technology (cellular) layout

Group technology (GT) groups parts with similar shape, size or processing needs into part families. The machines needed for one family are placed together in a cell, which works like a small product line inside a job shop.

  Process layout           Cellular layout
  [L][L] [M][M]            +-------+  +-------+
  [G][G] [D][D]            |L M G  |  |L D M  |
  (jobs travel far)        |cell 1 |  |cell 2 |
                           +-------+  +-------+

• Steps: classify parts (coding), form families, group machines, arrange cells.
• Advantages: shorter travel and lead time, less work-in-process, simpler scheduling, better quality, team responsibility.
• Disadvantages: machines may be under-used, cells may need reorganising when the product mix changes, and coding and rearrangement cost money.

GT layout is a compromise between the flexibility of process layout and the efficiency of product layout, and is suitable for medium-volume, medium-variety production.