Question

The Boston Cranberry Company operated a small facility where berries were unloaded from trucks, washed and packed, then delivered to local convenience stores for sale to consumers. The facility only operated during the cranberry-harvesting season, which lasted for 100 days each summer. Last year, the company experienced problems with the amount of overtime it had to pay truck drivers, who drove the cranberries from the local farms where they had been harvested to Boston Cranberry Company's facility for processing. In particular, by lunchtime, the cranberry holding bins (known as “dumper bins") had filled up, causing the incoming trucks to “back-up” and wait before they could unload their cranberries.

Mr. W. Boggs, the plant manager, was charged with fixing the problem. Several suggestions had been made, from adding more dumper bins to leasing more machines to speed up the plant’s processing rate. He asked you to advise him on the best approach.

On a typical day, trucks containing cranberries arrived at a rate of 6 trucks per hour, beginning at 8am, when the facility opened, and ending at 4pm, 8 hours later. The facility remained open until all of the berries had been washed and bagged. Each truck delivered a full truckload of berries. The trucks unloaded their berries into one of four dumper bins – each of which held two truckloads of cranberries. A conveyor belt carried the berries from the dumper bins into a single “washer” unit, where the berries were sprayed with a mixture of water and preservatives to ensure that they were clean. The washer had a maximum processing capacity of 5 truckloads/hour. After the cranberries left the washer, the conveyor belt dropped them into one of two “bagging” machines, where they were packed in plastic bags. Each of these machines had a maximum processing capacity of 2 truckloads/hour. The finished bags were manually loaded onto the company’s delivery trucks for delivery (you can ignore this part of the process).

1. 1) Draw the process flow for this operation.

2. 2) What is the bottleneck in this process (i.e., the limiting step)?

3. 3) How fast will inventory build up on a typical day (if at all)?

4. 4) Where does inventory build up in this process (if at all)?

5. 5) At what time will the trucks begin to wait (if at all)?

Answer 1

1. Process Flow

(i) Inbound Supplies: In this case process starts when the trucks bring the cranberries to the company’s facility and unload them in the dumper bins.

(ii) Washing of cranberries: Second step in the process flow is the moving cranberries from dumper bins to Washer unit through a conveyor belt for washing of cranberries.

(iii) Packing: Last step is packing of cranberries which is done by bagging machines, cranberries are brought to the bagging machine with the help of conveyor belt from the washer unit.

*Production of cranberries are not done by company therefore it shouldn’t be part of company’s process flow.

2. Bottlenecks

(i) Washer unit: It has only capacity of 5 truckloads per hour, however there is need of at least six truckloads per hour.

(ii) Bagging Machine (Packing):  Bagging machine can only pack 2 truckloads per hour but there is need of 6, although at current level capacity of 5 truckloads can also be enough if capacity of washer unit is not increased to 6.

3. Inventory build-up will be as follows:

Process	Inventory Build-Up (In Truckloads)
Per Hour	Per Day
Due to Washer unit	1	8
Due to Bagging	3	24

A total of 32 truckloads of inventory build-up will be there in company on daily basis at the current capacity level of all the processes.

4. Inventory Build-up will be at Dumper bins due to washer unit and at washer unit due to bagging machine.

5. At 10 A.M. trucks will be starting start to wait , every hour dumper bins will be having 1 truckload of inventory build up and they have capacity of 8 truckloads therefore after 2 hours of opening of facility trucks will be starting to wait.