Sa – Situation Anlysis
Pa – Problem Analysis
Da – Decission Analysis
Pa – Probabilty Analysis
1) Suppose that a peak harvest-season day involves 18,000 barrels of berries, 70% of them wet harvested, arriving uniformly over a twelve-hour period from 7 a.m. to 7 p.m., and process initiates as soon as the first truck arrives.
a) At what time during the day, would the trucks start queuing up to upload?
Answer: - Trucks carrying wet berries will have to wait to unload during the day because the incoming arrival rate is 1050 is greater than processing rate 600. The Trucks arriving with dry berries will not have to wait as processing is greater than arrival. Also, if Maximum storage capacity is been used for storing wet berries then total available will be 3200 bbls. Assuming all storage was empty @ 7:00 A.M , trucks delivering wet berries would have to start waiting after 10:00 A.M as the bins would be full (3200/1050 – 3.04 hours) Also, the Processing will be completed at 4:00 A.M on Peak Harvest Day assuming that work will start at 7:00 A.M
This has been assumed with following Logic – Considering that each truck carried the same number of Barrels; 1500 barrels (18,000/12) are delivered every hour over a period of 12 hours. Each truck will contain 1050 barrels (70%) of wet berries and 450(30%) barrels of dry berries. Thus, the total input for the day will be 12,600(70% of 18000) of wet berries and 5400(30% of 18000) of dry berries.
Since the process capacity is of bottleneck, the capacity of the cranberry process is 600 bbls/hour. Also, we have to take note that only wet berries go through the drying process and thus the processing of the dry berries are not affected by this. The process capacity of processing dry berries alone would be 1200 bbls per hour (Bottleneck = Quality Grading). However, even with the capacity of 1200 bbls per hour, all dry berries received per batch can be processed immediately (450 bbl/hr & lt; 1200 bbls/hr).
Since both types of berries are processed concurrently, the actual deciding factor for the process completion time should be the time taken to process all wet berries received.
b) How much truck waiting time (cumulative) would you expect?
Answer: - The rate @ which wet berries will be arriving will be
(18000 * 70% /12) = 1050
The rate for processing the berries is based on the bottleneck operation
The dryer’s capacity is 600 bbls/hr
After the bins are full the trucks will have to wait( 2200 bbls/ 600 bbls) which equals 3.4 or 3 hours and 40 minutes.
c) What is the maximum number of trucks waiting, at a give point in time, during the day?
Answer: - The maximum numbers of Trucks waiting will be 62.
Calculation Attached Below
The total volume of berries 12600
Average Truck hauls 75
Total # of Truck hauling wet berries per day 168
Number of trucks per hour arriving 14
Number of Trucks being processed after the Bins are full (600/75) 8
Bins Storage 3200
Total processed and in the Bins 8000
Volume not unloaded 4600
Maximum number of Trucks 61.33
d) If it costs $20 per hour to rent a truck and driver, how much money is spent by truck waiting on a peak day?
2) Is the investment in a Dryer a good option? Justify. (Weight: 10%)
Answer:-Overtime costs are too high and delivery trucks and their drivers have to wait several hours to unload. The trucks start delivering at 7 am whereas the processing does not start until 11 am. The trucks have to wait because the plant’s holding bins fill up and there is not temporary storage. The holding bins fill up because within the cranberry operating system there is...