Defects per million opportunities

FIGURE 2 Graphical illustration of the correspondence between the defects per million opportunity (DPMO) process capability (Cpk) and process sigma (assuming normally distributed quality variation). 

FIGURE 53.2 Printed circuit board yield decreases dramatically with increases in the number of solder joints per assembly if the defect rate per solder joint remains constant. For instance, at a 40 defects per million opportunities (DPMO) defect rate, the yield drops from 96 percent at 1,000 joints per assembly to 45 percent at 20,000 joints. 

What metrics will be used to monitor the performance of specific large projects Examples are DPMO (Defects Per Million Opportunities) and RTY (Rolled Throughput Yield). 

Six Sigma It is a quahty system which in effect aims for zero defects. Six Sigma in statistical terms means six deviations from the arithmetic mean. This equates to 99.99966 per cent of the total population, or 3.4 defects per million opportunities. 

Defect levels are most often measured as defects per million opportunities (DPMO), also called parts per million (PPM). A solder joint is one defect opportunity for defects such as opens, solder bridges, insufficient solder, etc. A component and its placement is also a defect opportunity for defects such as defective, wrong-value, and misaligned components. With a production run of... 

The DPMO (defects per million opportunities) metric is a standard (IPC-7912 DPMO for Printed Circuit Board Assemblies) way of reporting product quality. DPMO is the proportion defective with a scaling factor of one million. It is the defects per unit (x) divided by the defect opportunities (n) times one million, or dpmo = (x/n) 10. ... 

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