Total Productive Maintenance

277TPM Case Study: Sticky Foil

process as provided at between 8 and 24 hours, the majority of the soak times

for the returned products were within process specications. However, the

C

p

is 0.94 and the C

pk

is 0.76. This signies the process is not capable. The aver-

age soak time is 17.56 hours. The standard deviation is 4.964. The sigma level

is 2.28. The C

p

and C

pk

values are not equal, and this signies the process is

not centered. There is not sufcient evidence to show that the variability in

the soak time is a root cause of the sticky foil defects.

Figure15.9 shows the temperature at the cycle end; based on the normal

process, the tempera ...