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
Activity Immediate Predecessor(s) Normal Time (Weeks) Crash Time (Weeks) Normal Cost ($) Crash Cost ($) A 3 2 1000 1600 B 2 1 2000 2700 C 1 1 300 300 D A 7 3 1300 1600 E B 6 3 850 1000 F C 2 1 4000 5000 G D,E 4 2 1500 2000
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.| Activity | Time | Early Start (ES) | Early Finish (EF) | Late Start (LS) | Late Finish (LF) | Slack (S) |
|---|---|---|---|---|---|---|
| A | 3 | 0 | 3 | 0 | 3 | 0 |
| B | 2 | 0 | 2 | 2 | 4 | 2 |
| C | 1 | 0 | 1 | 11 | 12 | 11 |
| D | 7 | 3 | 10 | 3 | 10 | 0 |
| E | 6 | 2 | 8 | 4 | 10 | 2 |
| F | 2 | 1 | 3 | 12 | 14 | 11 |
| G | 4 | 10 | 14 | 10 | 14 | 0 |
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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