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Unformatted text preview: Tutorial 1
Equipment fractions Definition: the quantity of equipment required for an operation Can be determined by dividing total time required to perform an operation by the time
available to complete the operation
Let F = number of machines required per shift. We use the following model to estimate the
equipment fraction required: where S = “standard time”, time required per unit produced
Q = number of units produced (to be determined from “Scrap” or “Reject allowance”
calculations
H = amount of time available for production
E = historical efficiency of performing the operation. “Divide S by E”
R = historical reliability of the equipment. “Multiple H by R” Example: It takes 0.5 hr to duplicate a book 6 books are to be duplicated in 2 hr How many machine fractions are needed? STUDENT. 1.5 = 6*0.5/2.
Questions:
1. Are books actually being duplicated at the 0.5 hr per book rate?
2. Is the machine actually available when needed during the 2 hr period?
Solutions:
1. Let E = historical efficiency of performing the operation. Divide S by E.
2. Let R = historical reliability of the equipment. Multiple H by R.
Final formula: Discussion: What if the operation requires a setup time before production can begin? STUDENT. What if the setup time is on a per machine basis? STUDENT. Reject allowance example
Example (2.2 from textbook)
First, determine cost and revenue. The profit as a function of Q and x is: The expected profit from producing Q units is: See supplement Excel sheet for actual calculation ...
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 Spring '12
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