Caselet: Florida Oranges Inc. Florida Oranges Inc. (FO) makes orange juice conce
ID: 361385 • Letter: C
Question
Caselet: Florida Oranges Inc.
Florida Oranges Inc. (FO) makes orange juice concentrate in its Orangeville plant. The plant operates six days a week, 8 hours a day. The manufacturing steps that are capacity constrained are 1) Filter and 2) Concentrate, as shown in Fig 1.
Filter : In this step the orange peels and seeds are discarded and this step has a production capacity of 20,000 pounds per hour. However, before any filtration can start, at the start of day, the filter tank has to cleanse and filter screens replaced. The filtration can then start and production continues for 90 minutes before the step has to be stopped for cleansing and filter replacement. This involves a machine shutdown that lasts for 30 minutes.
Concentrate : This step does not require any set up and the concentration ( water removal ) can be done at the rate of 18,000 pounds per hour. Input Raw material : The plant receives oranges of different sizes ( small, medium and large) every morning and there is no constraint in receiving the raw material and feeding the plant. Only oranges of same size (small/med/large) can be processed in the factory line at a time, as the filter step requires corresponding size of filter screens. The aim of this exercise is to analyze the production scenario given – a continuous flow line and the role of buffer inventory. ( Buffer or suffer).
Base Case
Consider the plant processes only one size of oranges. Assume no buffer inventory. Estimate Average Output of concentrate per hour at the end of line. Utilization of the two steps Filter and Concentrate.
Case A : Base case plus buffer Inventory is allowed in between stages. Fig 2 Only one size of oranges. Estimate a) Average maximum output of concentrate per hour for the line b) Utilization of the two steps Filter and Concentrate c) Size of buffer required in pounds
Case B : The production is reengineered so that a new type of filter screens are used that allow the production run to be greater than the base case of 90 minutes ( as much as 5 hours). Production rates for the two steps (20,000 and 18,000 pounds per hour) unchanged. Buffer inventory is allowed. However, only one size of oranges processed at a time. Estimate a) Optimum production run of the Filter step once set up and the corresponding output of the line per hour. b) Utilization of the two steps Filter and Concentrate c) Size of buffer required in pounds
OrangesFilter Concentrate Juice Concentrate Setup 30 minutes FigRun 90 minutes No setup 18,000 pounds/hr 20,000 pounds/hr One size of orange at a time OrangesFilter | Juice Oranges centrate Concentrate --> Fig 2 Setup 30 minutes Bufer No No setup 18,000 pounds/hr Run 90 minutes 20,000 pounds/hr One size of orange at a time Note: To simplify matters, capacity is measured as pounds per hour of finished juice concentrate.Explanation / Answer
Base Case:
Only one type of orange, and no buffer inventory:
Filter: can process 20000 pounds/hour, runs for 90 minutes before 30 stoppage
hence in a period of two hours, it runs for 1.5 hours and process = 20000*1.5 = 30000 pounds
Concentrate: can process 18000 pounds per hour, hence 36000 pounds in two hours
But we have a limit from filter which is providing average 30000 pounds every two hours.
Average production = 30000/2 = 15000 pounds/hr
Utilization of filter = full = 100%............ since full capacity
utilization of concentrate = 15000/18000 = 83.33%
CaseA:
filter will work the same as before at 100% capacity producing average 15000 pounds/hr
we can have buffer to maximize the output of concentrate:
per hour we need 18000 - 15000 = 3000 pounds as buffer on average.
for a full day of 8 hours buffer required = 3000*8 = 24000 pounds
this way utilization of concentrate = 18000 pounds/hr = 100%
CaseB:
Here the filter step runs for 5 hours and then stops for 30 mins for setup.
Production of filter = 20000*5 = 100000 in 5 hours
Production of concentrate = 18000*5 = 90000 in 5 hours
Pounds left before concentrate = 100000 - 90000 = 10000 pounds (acts as buffer)
production in concentrate in half hour = 18000/2 = 9000 pounds
The 10000 pounds buffer will be consumed during the half hour stoppage of filter and still 1000 pounds will be left.
If at the start of the day the setup is done, a buffer of 9000 pounds required to run the concentrate from the start.
The utilization of both filter and concentrate will be 100%.
average output of the line will be subject to the production of concentrate which is 18000 pounds/hr
case6:
plant works 6 day and 8 hours per day = 6*8 = 48 hours in week
each size requires equal production of 1/3 each = 48/3 = 16 hours
basically each size can work for 2 days straight.
Schedule: Large size produced for 1st two days of the week.
Medium size produced for 3rd and 4th day of the week.
Small size processed for 5th and 6th day of the week.
everything else remains same as base case.