The Additive Method computes the DPM for each operation and then sums these values to determine the DPM for all operations. This method is best in stable situations where the same number of processes is always used in calculations.
Additive Method: ( DPM = DPM(process A) + DPM(process B)... DPM (process n))
|
|
Defects |
Sample Size |
DPM |
|
Process A |
7 |
50 |
140,000 |
|
Process B |
5 |
50 |
100,000 |
|
Process C |
3 |
50 |
60,000 |
|
Total DPM for All Operations (Additive Method): |
15 |
150 |
300,000 |
The Additive Method is more sensitive to process changes and is preferred by Motorola. This method should be used if you want to track the number of units running through the process.