Background
• Coating process uses fixtures (cans) to mask
part leaving the area to be coated exposed to
the coating material.
• Coating thickness is assessed by having a
positive correlation to the weight of the part
before and after coat (weight gain).
• Along with process variation, measurement
variation, tooling variation is also a significant
variation that is considered as a source of
variation.
Background
• Process is reaching its maturity and tool
wear is affecting the quality of parts.
• Can are stripped of excess coating after
five or ten run by an acid strip process and
are blasted with grit to ensure favorable
surface finish.
Data Collection
• The following data is collected
– Can runs
– Times the cans have been stripped
– WG variation in Cans
– Coating Times per can per run
Mean WG vs CAN ID
Scatterplot of mean vs id
0.0030
0.0029
mean
0.0028
0.0027
0.0026
0.0025
0.0024
0.0023
0
10
20
30
40
50
id
60
70
80
90
Deliverables
• Identify BOB (best of the best) and WOW (worst
of the worst) cans within the subset.
• Estimate life characteristics of the failed cans
(distributions).
• Reliability, Probability to failure, Mean Life,
Failure Rate will be calculated.
• Propose a preliminary age replacement plan
with cost dollars associated with it.
– Appropriate time for repair (weld repair, replace cans
after this many uses etc)