The average number of defects per unit. The ratio of defects to unit is the universal measure of quality.
D: number of Defects
U: number of Units
DPU may be estimated if the Throughput Yield (also called First Pass Yield) is known:
Take this table shown below as an example.
Ten nails were produced at a manufacturing facility and each nail has five ways (opportunities) it can be defective. If any one of the five characteristics fails, then the entire nail is considered defective.
There is a possibility of 50 total defects if each nail had all five characteristics (opportunities) fail.
The total number of defects (D) is 2+1+3+2+3+4+2+2 = 19.
The number of defectives is 8.
8 out of 10 nails contained one or more defects qualifying them as defective.
From the table:
D = 19 total defects were found
U = 10 units (nails)
DPU = 1.9 defects per nail
If all these defects could come from a SINGLE process (not in reality for this case, these types of defects occur from different operations), rearranging the formula above the TPY
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