Relationship between Throughput and WIP for Best Case
Relationship between Flow Time and WIP for Best Case
Best Case Performance
The best case performance for this line occurs when the congestion in the line is minimal. This occurs when jobs are processed and moved one at a time and there is absolutely no variability in the system.
We illustrate the best case behavior with a 4 station line with the following parameters.
Bottleneck rate rb = 0.5 parts/hour
Raw processing time T0 = 8 hours
Critical WIP W0 = 0.5 * 8 = 4 parts
Co-efficient of Variation a
= 0 (No variability, for best case).
In the following figures, we examine the throughput (TH) and flow time (FT) for various WIP levels.
Performance Summary for the Best Case
|
WIP |
TH |
FT |
TH x FT |
|
1 |
1/8 |
8 |
1 |
|
2 |
2/8 |
8 |
2 |
|
3 |
3/8 |
8 |
3 |
|
4 |
4/8 |
8 |
4 |
|
5 |
4/8 |
8 |
5 |
|
6 |
4/8 |
8 |
6 |
Performance for the Best Case
Based on above the following diagrams show the relationship between cycle time and throughput as it varies with
WIP for the best case.
|
Relationship between Throughput and WIP for Best Case |
|
|
|
Relationship between Flow Time and WIP for Best Case |
Performance Equations for Best Case, General Relationships
For a general infinite buffer closed line we can deduce the following relationship between cycle time and throughput
with WIP for the best case performance.
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and the maximum throughput (THbest) for a given WIP level, w is
given by,
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