Page 226 - Lean six sigma demystified

204 Lean Six Sigma DemystifieD

n = 101 Total assembly errors by type
101 100%
92 95% 98%
88.375 91% 90%
80%
75.75 70%
Number of errors 37.875 60%
63.125
50.5
50%
40%

25.25 30%
20%
12.625
4 3 2 10%
0 0%
Undersize Missing Off-Location Cold weld
Type
FIGURE 5-39 • Total assembly errors by type.

As you can see, undersize contributes most of the problem. This is clearly a
Pareto pattern: One defect accounts for 91% of the defects. Because the part is
undersized, it probably isn’t possible to rework the part, so it may have to be
scrapped.
If we had more detailed data about the undersize error, we might be able to
draw another more detailed Pareto chart of the data inside this one bar, but we
don’t. So we continue by creating an Ishikawa or fishbone diagram.

Ishikawa Fishbone Cause-and-Effect Diagram

Just click on the QI Macros and choose Fill in the Blank templates. Select
Ishikawa diagram (Fig. 5-40) and then change the problem statement to match

the Pareto pattern.
Your improvement story is now ready for root cause analysis. Knowing that
the problem is undersized, you can more easily choose the right team members
to help analyze the problem.

Move the Fishbone

If you want, you can move the Ishikawa template into the data workbook to
continue developing your improvement story in one Excel Workbook.
Just click on Edit–Move or Copy sheet to get this dialog box (Fig. 5-41).
Then change the “To Book” to the main data workbook (in this case AIAG SPC.xls)
and click OK.