Brightland Tech has just been awarded a contract to supply memory boards to a large consumer electronics manufacturer. Brightland must set up an assembly line to produce those memory boards at a rate of 300 boards per hour. Assembly of a single memory board requires completion of nine tasks, which are referred to as A1, A2, A3, B1, C1, C2, D1, D2, and El. All the tasks that start with the letter A must be finished before task B1 can start, and all the tasks that start with C and D must wait for B1 to finish before any of those can start. Finally, both tasks that start with C must be finished before task El can start. Each task requires 5 seconds to complete, except for tasks B1, D1, and D2, which each take 7 seconds to complete.

Questions 

1. Draw a precedence diagram using the information supplied, and calculate the cycle time for this assembly line. 

2. Design this assembly line for Brightland Tech, using longest processing time (LPT) as the decision rule for selecting tasks. Use the task names to break any ties under the LPT rule, by selecting that task that would come first in alphabetical/numerical order. Which tasks are completed at which workstations? 

3. How efficient is your design? Which workstation experiences the most idle time? 

4. Calculate the theoretical minimum number of workstations for Brightland Tech's assembly line. What does this calculation tell you about your own design?