Question

100 bottles entered a bottle-filling process that has three main stags.

The first stage produced 27 defects. The defects were found in 10 bottles.5 of them is reworked.

The second stage produced 57 defects . The defects were found in 15 bottles.10 of them is reworked.

The third stage produced 64 defects. The defects were found in 20 bottles.10 of them is reworked.

Determine and explain each of the following:

4. FTY for each of the three stages

5. FPY for each of the three stages

6. RTY using the FTY

Answer 1

4. FTY stands for first time yield. Here, the defect reworked are accounted for.

(Equation editor not working, hence typing again)

FTY1 = (100-10+5)/100 = 95/100 = 0.95
FTY2 = (95-15+10)/95 = 90/95 = 0.9474
FTY3 = (90-20+10)/90 = 80/90 = 0.8889

5. FPY stands for first pass yield. Here, the defect reworked are ignored. Also, note that the bottles without defect from the earlier stage are used as input for the next stage.

(Equation editor not working, hence typing again)

FPY1 = (100-10)/100 = 90/100 = 0.9
FPY2 = (95-15)/95 = 80/95 = 0.8421
FTY3 = (90-20)/90 = 70/90 = 0.7778

6. RTY stands for Rolled Throughput Yield. It is the probability of passing through all the steps after including the reworking. So, here, we have:

(Equation editor not working, hence typing again)

RTY = FTY1 * FTY2 * FTY3 = 0.95 * 0.9474 * 0.8889 = 0.8.