# Ncc Case

Topics: Harshad number, Time, Bottleneck Pages: 6 (1281 words) Published: July 22, 2012
National Cranberry Cooperative

Ques 1: Draw a detailed process flow map of the current process at receiving Plant#1. What is the capacity of each operation in the process?

Refer to the power point presentation.

2. What is the maximum long-term achievable throughput rate of receiving Plant 1? What factors affect this throughput rate?

The Truck arrival rate is at 20 Trucks/Hr. This year based on the numbers there is going to be 70% Wet and 30% Dry Berries. Dried Berries:
Throughput rate = 30% of 20 Trucks = 6 truck (dried)/hr @ 75 bbls = 450bbls/hr
Wet Berries:
Current Throughput rate possible = 600 bbls/hr or 8 Trucks/hr (Bottleneck) Since 70% of 20 Trucks implies 14 Trucks/hr, we can expect the maximum long-term achievable throughput rate at 14Trucks/hr for Wet berries. Long-term achievable throughput rate of Receiving Plant 1 = 450 bbls/hr + 600 bbls/hr = 1050 bbls / hr.

3. Currently what is (are) the major reasons for trucks waiting and excessive over time?

The major reason for trucks waiting and excessive over time is caused by the bottlenecks in the existing system. The Drying station is the bottleneck in the current system. The maximum input to the Dryer station is an average of 1050 bbls/hr but it can only handle a maximum capacity of 600 bbls/hr. As the input rate exceeds the maximum capacity of the station, the waiting times have become inevitable. The next vulnerable bottleneck is the “Jumbo Separator” system. Once the Drying station capacity is increased to meet the input rates, the input rate (20 Trucks/hr) for Jumbo Separators exceeds the maximum capacity of the station (16 Trucks/hr).

4) On average, how long will trucks have to wait on a busy day? Assume at 11a.m. start of processing of berries and a continuous arrival of berries of 1500 bbls/hr? As the Drying station is the bottleneck, it would be enough to consider only the wet berries processing capacities into consideration to estimate the waiting times of the trucks. The Dry berries will flow through the system as the input rates of dry berries are always less than the maximum capacity of its processing stations. Time| No of trucks in waiting| Berries waiting in bins | waiting in truck + bins| 7:00 AM| 0| 14| 14|

8| 0| 28| 28|
9| 0| 42| 42|
10:00 AM| 14| 42| 56|
11| 20| 42| 62|
12| 26| 42| 68|
1| 32| 42| 74|
2| 38| 42| 80|
3| 44| 42| 86|
4| 50| 42| 92|
5| 56| 42| 98|
6| 62| 42| 104|
7:00 PM| 54| 42| 96|
8| 46| 42| 88|
9| 38| 42| 80|
10| 30| 42| 72|
11| 22| 42| 64|
12| 14| 42| 56|
1| 6| 42| 48|
2| 0| 40| 40|
3| 0| 32| 32|
4| 0| 24| 24|
5| 0| 16| 16|
6:00 AM| 0| 8| 8|

By 10:00 AM all the Bins (17 -24 and 25 -27) are completely filled with Wet Berries, as the Bins (1-16) cannot be used for Wet Berries, the Trucks have to wait in the queue.

After 07:00 PM there is no more receiving.

Arrival Rate = 1500 bbls/hr = 20@75 bbls/hr = 20 Trucks/hr.
Total trucks arrived 12hr * (20 trucks/hr * 70%) = 168 trucks. Total waiting hours = SUM (No. of Trucks in Waiting) = 552
Average waiting hours per truck 552/ 168 = 3.28 hrs/truck.

5) On average, how long will the trucks have to wait on a busy day? Assume a 7a.m. start of processing of berries and a continuous arrival rate of berries 1500 bbls/hr. Time| No of trucks in waiting | waiting in bins| waiting in truck + bins| 7:00 AM| 0| 6| 6|

8| 0| 12| 12|
9| 0| 18| 18|
10:00 AM| 0| 24| 24|
11| 0| 30| 30|
12| 0| 36| 36|
1| 0| 42| 42|
2| 6| 42| 48|
3| 12| 42| 54|
4| 18| 42| 60|
5| 24| 42| 66|
6| 30| 42| 72|
7:00 PM| 22| 42| 64|
8| 14| 42| 56|
9| 6| 42| 48|
10| 0| 40| 40|
11| 0| 32| 32|
12| 0| 24| 24|
1| 0| 16| 16|
2:00 AM| 0| 8| 8|
3| 0| 0| 0|
4| 0| 0| 0|
5| 0| 0| 0...

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