Page 224 - DMGT206_PRODUCTION_AND_OPERATIONS_MANAGEMENT

Unit 11: Facility Planning and Layout

matrix and a distance matrix as initial inputs, but in addition, it also requires a cost to be Notes
computed per unit distance traveled, say, ` 1.50 per meter moved.
With these inputs and an initial layout in the program, CRAFT tries to improve the relative
placement of the departments as measured by total material handling cost for the layout. The
relationship that it uses is similar to the Load Distance Model:

Material handling cost between departments = Number of loads × Rectilinear distance between
department centroids × Cost per unit distance.
The program simulates different arrangements of layout and then makes improvements by
exchanging pairs of departments iteratively until no further cost reductions are possible.

11.3.3 Advantages and Disadvantages of Process Layout

Process Layout is best suited for non-standardized products; where there is a low volume, high
variety manufacturing environment; where the market requires frequent change in product design;
in job-shop manufacturing; and for setups where very expensive or specialized machines like
CNC milling, coordinate measuring machine etc., are required to be used. Its advantages are:

1. Initial investment in process layout is low.
2. Varied degree of machine utilization may be achieved in process layout, as machines are
not dedicated to any single product.

3. There is greater flexibility and scope of expansion.
4. High product variety can be easily handled, therefore different product designs and varying
production volumes can be easily adopted.

5. The overhead cost is low.
6. Breakdown of one machine does not result in total stoppage of production. Maintenance
of machines is relatively easy as it can be scheduled without greatly impacting production.

7. Easy, effective and specialized supervision of each function area is easy to achieve. With
different departments for different processes, better teamwork can be achieved.
8. There is low setup and maintenance cost compared to other layouts.

Though the advantages outweigh the disadvantages in job shops and batch production, there are
some disadvantages of Process Layout:
1. There is high degree of material handling. Parts may have to backtrack in the same
department.
2. Large work in process inventory is common. This may lead to more storage area.
3. Workers are more skilled. This is because of variety in products and difference in design,
therefore, labour cost is higher.
4. Total cycle time is high. This is due to waiting in different departments and longer material
flow.
5. Inspection is more frequent which result in higher supervision cost.
6. It is difficult to fix responsibility for a defect or quality problem. The work moves in
different departments in which the machine preference is not fixed. Therefore, which
machine or which operator was faulty during a quality lapse may be difficult to trace in
some cases.
7. The production planning and control is relatively difficult.

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