How is rolled throughput yield calculated?
When you calculate throughput yield, you count only the units that make it through the process without rework or scrap. Using the example above, YRT = YTP at step 1 * YTP at step 2 * YTP at step 3. So the rolled throughput yield for the label process is 0.95 * 0.84 * 0.88 = 0.70.
What is the difference between first time yield and rolled throughput yield?
As we see, FTY calculates only with scrap, FPY takes rework into account, while RTY counts in all defects, giving the most strict result. Whenever it’s possible, use Rolled Throughput Yield (RTY) or at least First Pass Yield (FPY), instead of using First Time Yield (FTY).
What is equivalent throughput yield?
Throughput Yield (TPY) is the number of acceptable pieces at the end of the end of a process divided by the number of starting pieces excluding scrap and rework (meaning they are a part of the calculation).
What is the main difference between FTY and RTY?
Mathematically, RTY is the result of multiplying together the FTYs from each process step. When a process step produces defects, the yield for that step will be less than 100 percent.
Why use rolled throughput yield?
RTY allows us to expose the “hidden factory” by providing visibility into the yield of each process step. This helps us identify the poorest performing process steps and gives us clues into where to look to find the most impactful process improvement opportunities.
What is DPMO Six Sigma?
DPMO is stated in opportunities per million units for convenience: Processes that are considered highly capable (e.g., processes of Six Sigma quality) are those that experience fewer than 3.4 defects per million opportunities (or services provided).
Why is rolled throughput yield important?
What is the yield of 6 Sigma?
Sigma levels
| Sigma level | Sigma (with 1.5σ shift) | Percentage yield |
|---|---|---|
| 3 | 1.5 | 93.3% |
| 4 | 2.5 | 99.38% |
| 5 | 3.5 | 99.977% |
| 6 | 4.5 | 99.99966% |
What is DPO and DPU in quality?
Unlike DPU, which gives you a better understanding of how many units to expect to leave the process with errors, DPO gives you an understanding of the true failure chance for a defect to occur. In the example above, the DPU, or defects per unit, is 0.06, or a 6% chance of a unit having a failure.
What is the purpose of RTY?
Rolled Throughput Yield (RTY) is a process performance measure that provides insight into the cumulative effects of an entire process. RTY measures the yield for each of several process steps and provides the probability that a unit will come through that process defect free.
What is DPU and DPO?
What is the difference between PPM and DPMO?
For me, DPMO is defects per million of opportunities and PPM is defective parts per million parts. The differences are clear: A defective part can have one or more defects, and a part can have one or more opportunities.