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3. JW Famcor Company makes an artificial leather-like product for the fashion accessory market. The material is made in sheets and has the appearance of a thin rug. Each sheet is 36 inches wide and 100 feet long and is wound into a roll. The quality manager has requested that 100 rolls be inspected. Twenty-seven non-conformances were found. a. Calculate the nonconformances per unit (NPU) and the throughput yield (TY). b. If the production process consists of three steps, with step 1 having a TY of 93 percent; step 2, 89 percent; and step 3, 92 percent, what is the rolled throughput yield (RTY), and the proportion nonconforming?
Expert Answer
Answer to question a :
Non-conformance per unit = Number of non-conformances found/ Number of units inspected = 27/100 = 0.27
Hence , Throughput yield = 1 – Nonconformance per unit =1 – 0.27 = 0.73
Thus, Throughput yield expressed in percentage = 0.73 x 100 = 73 %
| NON CONFORMANCE PER UNIT ( NPU) | 0.27 |
| THROUGHPUT YIELD | 73 % |
Answer to question b :
Rolled throughput yield (RTY)[1] is the probability that a process with more than one step will produce a defect free unit. It is the product of yields for each process step of the entire process.
Thus Rolled Throughput Yield ( RTY)
= Throughput yield of step 1 x Throughput yield of Step 2 x Throughput yield of Step 3
= 0.93 x 0.89 x 0.92
= 0.76148 ( or 76.15% BY ROUNDING TO 2 DECIMAL PLACES )
Therefore proportion non conforming ( expressed in % terms )
= 100 – 76.15 = 23.85%
| ROLLED THROUGHPUT YIELD | 76.15% |
| PROPORTION NON CONFORMING | 23.85% |
