3 ms·
You forgot the part where the customer have already paid for working parts.
by tokai 4y ago
You forgot the part where the customer have already paid for working parts.
- pif 4y agoOnly if he actually paid for working parts. He who buys cheap, he deserves cheap.
- AnimalMuppet 4y agoIf I buy a part, I'm paying for a working part. If I buy a million parts, I'm probably paying for an acceptable (to me) failure rate, which is probably negotiated as part of the contract. He who buys cheap, buys a higher failure rate.
- Shish2k 4y agoMost people are happy paying moderate prices for 99.9% reliability. Very few people are willing to pay extreme prices for 99.99999% reliability.
- th3typh00n 4y agoWhen the cost of the electronics is a tiny fraction of the overall product the equation is different. Automotive is a perfect example where spending extra on a few key components is a worthwhile investment if that can increase the reliability of the entire vehicle.
- kurthr 4y agoActually, 1000dppm (99.9% defective parts per million) is not acceptable except for hobbyists. Typical commercial manufacturing requires <100dpppm due to the number of components and cost of returns. This can be met quite reasonably with statistical sampling and process controls. Every single IC gets tested, it's just a question of how thoroughly and whether the control limits are set well. You need to do R&R studies, but the infrastructure/procedures are usually available to approach 6sigma (even if it's a bit hokey). Where this is going a bit nuts is that that it's hard to make 100 gold contacts last for 1000 compression cycles at 1 dppm (better than 6 sigma!). That requires a lot of excess maintenance on the test infrastructure! That will be expensive... and your assembly connectors/SMT is likely orders of magnitude higher defect rate than 10dppb so it won't improve final assembly performance. Also, I think you need another 9 on that 99.99999% to hit 10ppb and realistically 2, if you want to have an acceptable yield rate, and 3 on the test equipment since they are used 10k times every day.
- CRConrad 4y ago> > Most people are happy paying moderate prices for 99.9% reliability. Very few people are willing to pay extreme prices for 99.99999% reliability. > Actually, 1000dppm (99.9% defective parts per million) is not acceptable except for hobbyists. Exactly: There are many more hobbyists than manufacturers, so most people are content to pay lower prices for lower reliability.
- Animats 4y agoIf the unit that has to be replaced is large enough, as it is for cars, it pays to get the component reliability up. Failure of IC can mean replacement of dashboard or power train.
- deelowe 4y agoI'm confused. Is the issue that the parts are out of spec or that the auto makers want to up the spec?
- AnimalMuppet 4y agoNot-working parts are out of spec (kind of by definition).
- deelowe 4y agoNot true. Every supplier worth it's salt will provide you with quality details as part of the product spec (and cost and schedules/volume). 100% is rarely the expectation.
- metaphor 4y agoIt appears you're conflating the parametric/functional spec of a product with the statistical spec of a process in manufacturing said product at volume.