Dear Sir,
1.First you should study & analyse field failures.The phenomenon, which you have mentioned, is very common, when you test as per standards such as JIS or DIN.In spite of no failures in Lab. testing,there are failures in the field.The main reason is that the field stresses are different than the Designed stresses such as Vibrations, Thermal, Humidity,use & missuse by the customers. Good organisations treat use & missuse by customers as a noise factor during design stage.
2.You should study the stresses operating on your product in the field & plan a Multi Environmental Overstress Testing.A good MEOST produces failure mostly within 32 hours.The failure may not be identical as in field, but if failure from MEOST is similar to the one in field, you may treat testing as successful.By this you can improve the product & subject the improvement to MEOST for another 32 hours, may be 40 hours due to improvement. The purpose testing is to improve Reliability & Durability.
3.You can get practicle knowledge on MEOST in the book ‘The World Class Reliability’ by Mr. Keki R. Bhote [ Publishers-American Management Association ].
4.The methodology I have suggested will not only save your enormous testing time, sometimes 50:1,also improve reliabilty.You have to invest in new chambers.
5. Since you will be giving a huge saving to the company,expect a big PROMOTION.Pl. don’t forget me for a treat.
6.Pl feel free to ask any queries.
With warm regards,
R.M.Parkhi
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