Suppose you want to use
Product
Report
to perform successive rollups in order to determine the overall performance
measures for a complex product. In this example, assume you have a product
composed of the following assemblies:

- Assembly 1 requires 2 units of subassembly 1-1 and 1 unit of subassembly 1-2.
- Assembly 2 requires 4 units of subassembly 2-1, 2 units of subassembly 2-2, and 1 unit of subassembly 2-3.
- Assembly 3 requires 1 unit of subassembly 3-1, 1 unit of subassembly 3-2, and 6 units of subassembly 3-3.

The end product requires 4 units of assembly 1, 2 units of assembly 2, and 1 unit of assembly 3.

Combine the data from subassembly 1-1 and subassembly 1-2 to make the report for assembly 1.

C1 | C2 | C3 | C4 | C5 |
---|---|---|---|---|

Sub-assembly | Defects | Units | Opps/Unit | Z.Shift |

1-1 | 61 | 140 | 26040 / 140 = 186 | 1.24 |

1-2 | 26 | 162 | 6156 / 162 = 38 | 1.23 |

In the process of making 70 units of assembly 1, there are 72 defects. Overall, assembly 1 has a Z = 4.044 and YRT = 0.3558. Thus, the probability of making one unit of assembly 1 with 0 defects is ~ 36%.

Use the following data to make the report for assembly 2.

C1 | C2 | C3 | C4 | C5 |
---|---|---|---|---|

Sub-assembly | Defects | Units | Opps/Unit | Z.Shift |

2-1 | 69 | 241 | 16147 / 241 = 67 | 1.42 |

2-2 | 30 | 307 | 7675 / 307 = 25 | 1.26 |

2-3 | 36 | 162 | 10692 / 162 = 66 | 1.36 |

In the process of making 60 units of assembly 2, there are 94 defects. Overall, assembly 2 has a Z = 4.035 and YRT = 0.2089. Thus, the probability of making one unit of assembly 2 with 0 defects is ~ 21%.

Use the following data to make the report for assembly 3.

C1 | C2 | C3 | C4 | C5 |
---|---|---|---|---|

Sub-assembly | Defects | Units | Opps/Unit | Z.Shift |

3-1 | 26 | 203 | 7308 / 203 = 36 | 1.39 |

3-2 | 47 | 210 | 13440 / 210 = 64 | 1.41 |

3-3 | 45 | 160 | 7680 / 160 = 48 | 1.42 |

In the process of making 60 units of assembly 3, there are 136 defects. Overall, assembly 3 has a Z = 3.984 and YRT = 0.1034. Thus, the probability of making one unit of assembly 3 with 0 defects is ~ 10%.

You would expect to see 162 defects in 17 products. The entire product has a Z = 4.023 and YRT = 0.000073. Thus, the probability of producing an entire product with 0 defects is essentially 0. Considering the large opportunity count (48620 total opportunities divided by 17 products is 2860 opportunities per product) and the Z of 4, this result is expected.

The three assemblies are almost identical in capability, with Z values very close to 4.