The Operations Manager of a Body and Paint Shop Has

question 21

Essay

The operations manager of a body and paint shop has five cars to schedule for repair. He would like to minimize the throughput time (makespan) to complete all work on these cars. Each car requires body work prior to painting. The estimates of the times required to do the body and paint work on each are as follows:
$$\begin{array} { | c | c | c | } \hline \text { Car } & \begin{array} { c } \text { Body Work } \\\text { (Hours) }\end{array} & \text { Paint (Hours) } \\\hline \text { A } & 8 & 7 \\\hline \text { B } & 9 & 4 \\\hline \text { C } & 7 & 9 \\\hline \text { D } & 3 & 4 \\\hline \text { E } & 12 & 5 \\\hline\end{array}$$ a. Chart the progress of these five jobs through the two centres on the basis of the arbitrary order
A→B→C→D→E.
b. After how many hours will all jobs be completed?
$$\begin{array} { | l | l | l | l | l | l | l | l | l | l | l | } \hline \text { Body Work } & & & & & & & & & & \\\hline \text { Paint } & & & & & & & & & & \\\hline & 5 & 10 & 15 & 20 & 25 & 30 & 35 & 40 & 45 & 50 \\\hline\end{array}$$ c. Use Johnson's rule to sequence these five jobs for minimum total duration. Show your work in
determining the job sequence.
d. The optimal sequence is ________.
e. Chart the progress of the five jobs in this optimal sequence.
f. After how many hours will all jobs be completed?

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Definitions:

Crash Duration

The shortest possible time for which an activity or project phase can be scheduled after allocating the maximum amount of resources.

Total Cost

The complete cost of producing or acquiring goods or services, including variable costs, fixed costs, and any other relevant expenses.

Network Diagram

A visual representation of a project's activities and their interdependencies, often used to plan and monitor project timelines.

Expected Duration

The anticipated amount of time which will elapse before a particular project or activity is completed.