Bolling Electronics manufactures DVD players for commercial use - Project CrashingProject Crash Example

Problem Data

It is required to calculate the crash schedule of the activities in order to reduce the time of the project, according to the following data:

Number of Activities
7
Target Time
7
Time Unit
Weeks
Description
Bolling Electronics manufactures DVD players for commercial use - Project CrashingBolling Electronics manufactures DVD players for commercial use. W.Blaker Bolling, president of Bolling Electronics, is contemplating producting DVD players for home use. The activities necessary to build an experimental model and related data are listed in the table. (a) What is the project completion time? (b) Accelerate the project up to 7 weeks (the maximum that can be accelerated) at the lowest cost.
Table of Activities
ActivityImmediate Predecessor(s)Normal Time (Weeks)Crash Time (Weeks)Normal Cost (\$)Crash Cost (\$)
A3210001600
B2120002700
C11300300
DA7313001600
EB638501000
FC2140005000
GD,E4215002000

Solution

The following are the calculations and detailed graphs to obtain the critical path according to the data provided:

Step 1: Proyecto con tiempos normales

Network Diagram

The following chart shows the project activities, calculated with normal times:

The activities in red represent the critical path.

Normal Project Time Table

The following table presents the times for each activity. The critical path activities are highlighted in green.
ActivityTimeEarly Start (ES)Early Finish (EF)Late Start (LS)Late Finish (LF)Slack (S)
A303030
B202242
C101111211
D73103100
E6284102
F213121411
G4101410140

The critical path of the project is: A → D → G

The total time of the project (with normal times) is 14 Weeks

Since the project is required to be completed within 7 Weeks, some activities must be crashed to meet the goal. The procedure will be detailed in the next step.

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