You have just been assigned the job of setting up an electric fan assembly line with the following tasks and precedence relationships:

Task       Time (minutes)        Description                                    Predecessors

A            2.8                         Assemble Frame                               None

B            2.1                         Assemble motor housing                   None

C            1.1                        Mount motor housing in frame           A,B

D           0.5                         Attatch Blade                                     C

E           1.8                        Assemble and attatch safety grill        D

F           1                             Test                                                    E

The assembly line will be running 8 hours per day and 5 days per week. The demand forecast is 500 items per week. Your goal is to minimize the number of workstations necessary to complete enough units to satisfy the demand forecast.

a) Draw the precedence diagram.

b) What is the takt time (in minutes) that we need to produce the required number of units?

c) What is the theoretical minimum number of workstations that you will need?

d) Assign the tasks to the workstations to balance the line using the longest operating time rule (meaning the takt time you calculated above).

e) What is the efficiency of the balanced line? Since you have a balanced line with workstations, the takt time will be equal to the maximum total time among your workstations.