G
gtg168w
I am tasked to put a new inspection method in place at a plastic injection molder who currently relies heavily on 100% inspection. We are ISO9001, and have automotive (TS16949) and aerospace (AS9001) customers.
1 - If Can I use a c=0 acceptance sampling plan, lets say c=0 and AQL=0.065%? I know AQL=0.065% requires larger sampling sizes per lot, but it is a lot smaller than the current 100% sample size.
1a - Can a c=0 AQL=0.065% sampling plan be used without a CPK calculated for that process? I plan on using attribute charts (p-chart) for each process no matter what just because of their ease of use on the shop floor.
2 - CPK - For multicavity tools and for AIAG PPAP compliance, what's the best way to subgroup my sample pieces? I believe the PPAP manual says 100 samples in subgroup sizes of 4 or 5 samples? I am assuming it is best to group by cavity, this way the within-subgroup variation is smaller, resulting in better cpk indices?
2a - Do capable processes via CPK require ongoing monitoring? If so, I believe attribute charts would no suffice for this. Can attribute charts be used to monitor process control, but not used to revalidate the cpk? I know some companies are starting to require CPK validation yearly or every 2 years. Does this require on going SPC data every run? Or can I just make a "maintenance" schedule for my processes and know that by next month I need to repeat a capability study for this part/tool to meet the customers validation reqs?
3 - Do I have to ask the customer if they approve of my newly implemented inspection plan? I don't want to raise any unnecessary red flags. Of course, our goal of zero defects and 100% customer satisfaction is still the same.
4 - If a process is not capable after a capability study, say cpk is 1.0-1.3 or is below 1, can c=0 AQL=0.065% still be used? Or should I revert to 100% inspection?
1 - If Can I use a c=0 acceptance sampling plan, lets say c=0 and AQL=0.065%? I know AQL=0.065% requires larger sampling sizes per lot, but it is a lot smaller than the current 100% sample size.
1a - Can a c=0 AQL=0.065% sampling plan be used without a CPK calculated for that process? I plan on using attribute charts (p-chart) for each process no matter what just because of their ease of use on the shop floor.
2 - CPK - For multicavity tools and for AIAG PPAP compliance, what's the best way to subgroup my sample pieces? I believe the PPAP manual says 100 samples in subgroup sizes of 4 or 5 samples? I am assuming it is best to group by cavity, this way the within-subgroup variation is smaller, resulting in better cpk indices?
2a - Do capable processes via CPK require ongoing monitoring? If so, I believe attribute charts would no suffice for this. Can attribute charts be used to monitor process control, but not used to revalidate the cpk? I know some companies are starting to require CPK validation yearly or every 2 years. Does this require on going SPC data every run? Or can I just make a "maintenance" schedule for my processes and know that by next month I need to repeat a capability study for this part/tool to meet the customers validation reqs?
3 - Do I have to ask the customer if they approve of my newly implemented inspection plan? I don't want to raise any unnecessary red flags. Of course, our goal of zero defects and 100% customer satisfaction is still the same.
4 - If a process is not capable after a capability study, say cpk is 1.0-1.3 or is below 1, can c=0 AQL=0.065% still be used? Or should I revert to 100% inspection?