100-Metodos-de-Qualidade-Total

56 100 METHODS FOR TOTAL QUALITY MANAGEMENT
Method 20
Pareto analysis
Purpose
To separate the most important causes of a problem from the many trivial.
Also, to identify the most important problems for a team to work on.
Pareto analysis was first used by Wilfredo Pareto, an Italian economist.
When to use
When a team is analysing data relating to a problem to decide which are
the most important factors to be tackled first to have the most impact on
the problem.
Table 1 Pareto analysis
Error description Error code Count % of total Cumul. %
Wrong component 33 3,138 22.95 22.95
Missing component 51 2,541 18.59 41 .54
Not soldered 71 1,382 10.11 51.65
Other solderfPB problems 92 1,307 9.56 61 .21
Wrongly inserted 54 1,142 8.35 69.56
Shorts-solder side 77 83 1 6.08 75 .64
Electrical defect 12 722 5.28 80.92
Wrong placement
687 5.03 85.95
Shorts caused by components 56 649 4.75 90.70
Test equipment . . . 94 523 3.83 94.52
Not correctly inserted 61 237 1.73 96.25
PB faults 91 178 1.30 97.56
Electrical out of tolerance 15 83 0.61 98.16
Mechanical defect 11 78 0.57 98.73
SMD alignment 58
0.43 99.17
Shorts-component side 78 51 0.37 99.54
Protrusion length 46 23 0.17 99.71
Documents progr. faults 93 19 0.14 99.85
Additional component 52 8 0.06 99.90
SMD tombstone-effect 59 6 0.04 99.95
Missing label 95 3 0.02 99.97
Dirt 22 I 0.01 99.98
Broken solder joint 76 1 0.01 99.99
Ball-shaped solder joint 82 0 0.00 99.99
Component damaged 41
0.01 100.00
Total 13 671 100.00
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