Hi all, I sure could please use some advice on how to perform variable sampling for design verification of a product. Too be honest, I'm not even sure how you'd do it, because you need to calculate your Ppk but design verification should occur BEFORE you start ramping up significant numbers of product to use for test samples.
If I manufactured a batch of 20 products and I had performed a 100% measurement/verification check (of continuous/variable data) so that I don't need to validate the manufacturing process, but I have to put all 20 products through a shipping test and confirm they still work with a variable sampling plan (for design verification), then can I calculate my Product Performance Index (Ppk) using data from the earlier 100% check from my manufacturing process?
To give some more details (if you're interested in my tale)...
My product is a medical device, but this question should still apply to non-medical device products. Basically, my product is super expensive and my company will only be making 20 of them to start with. We're doing a 100% verification check after assembly, so thus the manufacturing process will not be validated. However, one of our product requirements is that the finished product must survive shipping in our package and remain functional. Our product uses a gyroscope sensor to detect angles. So our functional test (after shipping) is to confirm that the product can detect angles within acceptable parameters of accuracy.
The only hang-up is that because this design verification activity is a true "test", not just a simple inspection/demonstration/analysis. Thus, the both the US FDA and European Union will expect us to have a statistical approach for this test (per the standard ISO 13485 - basically required by EU and FDA is currently transitioning to use the standard as well).
Sounds great, right? My test is measuring the angles that my product measures, which is continuous (variable) data. So I'd use a variable sampling plan, which allows for lower sample size, and I already know my specification limit. But I can't calculate a Product Performance Index (Ppk) without previous measurements! I have no historical data from similar products and a small population because the cost is so high. Can I just take the data from my earlier 100% check of the manufacturing process, and use that to calculate the Ppk in this new shipping test?
If I manufactured a batch of 20 products and I had performed a 100% measurement/verification check (of continuous/variable data) so that I don't need to validate the manufacturing process, but I have to put all 20 products through a shipping test and confirm they still work with a variable sampling plan (for design verification), then can I calculate my Product Performance Index (Ppk) using data from the earlier 100% check from my manufacturing process?
To give some more details (if you're interested in my tale)...
My product is a medical device, but this question should still apply to non-medical device products. Basically, my product is super expensive and my company will only be making 20 of them to start with. We're doing a 100% verification check after assembly, so thus the manufacturing process will not be validated. However, one of our product requirements is that the finished product must survive shipping in our package and remain functional. Our product uses a gyroscope sensor to detect angles. So our functional test (after shipping) is to confirm that the product can detect angles within acceptable parameters of accuracy.
The only hang-up is that because this design verification activity is a true "test", not just a simple inspection/demonstration/analysis. Thus, the both the US FDA and European Union will expect us to have a statistical approach for this test (per the standard ISO 13485 - basically required by EU and FDA is currently transitioning to use the standard as well).
Sounds great, right? My test is measuring the angles that my product measures, which is continuous (variable) data. So I'd use a variable sampling plan, which allows for lower sample size, and I already know my specification limit. But I can't calculate a Product Performance Index (Ppk) without previous measurements! I have no historical data from similar products and a small population because the cost is so high. Can I just take the data from my earlier 100% check of the manufacturing process, and use that to calculate the Ppk in this new shipping test?