Skip to content
Sem 5 Prep
← OperationsProcess layout and CRAFT

Formulas for this chapter

Process-layout cost

Minimise SUM(i) SUM(j) Xij x Cij

Scoring any process layout. Cij is normally the handling rate times the centroid-to-centroid distance.

Xij
Number of loads moved from department i to department j
Cij
Cost to move one load between departments i and j
n
Total number of work centres or departments

Rectilinear centroid distance

d(i,j) = |xi - xj| + |yi - yj|

Building the distance matrix in a layout problem, exactly as the class CRAFT spreadsheet does with ABS formulas.

(xi, yi)
Centroid of department i in the layout
(xj, yj)
Centroid of department j

Adjacency cost rule

Cost of a flow = loads x rate, rate = 1 unit if departments are adjacent, 2 units if they are more than one apart

The simplified rule the class uses for the six-department factory, when only adjacency is given rather than distances.

loads
Number of moves between the two departments per period
rate
1 for adjacent, 2 for non-adjacent, in the units the question gives
Step 3 of 20
The real wordsTheory

Two matrices, one score

From-to matrixInterdepartmental work flows: how many loads move from each department to each other department per period.
Distance matrixHow far apart the departments are in the layout being tested, usually between centroids.

Multiply them cell by cell and add. That single number, the load-distance score, is what a layout is judged on.

The flow matrix belongs to the product. The distance matrix belongs to the layout. Only the second one is yours to change.

← BackContinue →