Using Product Report for Successive Rollups
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Suppose you wish to use the 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 3 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.

The product reports show:

Assembly 1 - Subassembly 1-1

Assembly 1 - Subassembly 1-2

Combine the Product Report data from subassembly 1-1 and subassembly 1-2 to make the report for assembly 1:

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

Entire Assembly 1

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. In other words, the probability of making one unit of assembly 1 with 0 defects is ~ 36%.

 

Assembly 2 - Subassembly 2-1

Assembly 2 - Subassembly 2-2

Assembly 2 - Subassembly 2-3

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

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

Entire Assembly 2

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. In other words, the probability of making one unit of assembly 2 with 0 defects is ~ 21%.

 

Assembly 3 - Subassembly 3-1

Assembly 3 - Subassembly 3-2

Assembly 3 - Subassembly 3-3

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

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

Entire Assembly 3

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. In other words, the probability of making one unit of assembly 3 with 0 defects is ~ 10%.

 

Entire Product

You would expect to see 162 defects in 17 products. The entire product has a Z = 4.023 and YRT = 0.000073. This means that 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 is to be expected.

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