The most exciting and nerve wracking thing a product design team ever does is test their final product. It is nerve wracking because there is always the chance that it might fail. You wake up in the night worried that you didn't work out the x factor and the joints will fail. You stay up late at night calculating the forces that the testing it going to exert and trying to convince yourself that you took all of them into account, front loading, side loading and all. You think about the people running the test, since you cannot be there or you may influence it, and what they might do wrong.
Then the test begins. No use worrying about it any more. There is nothing you can do. But Wait.
Finally, after the first day of testing and 40 phone calls to the test director, he calls you back. "Yep, 1000 cycles. No problem. We'll start her back up tomorrow."
You breath a sigh of relief and you start planning the next test. After life cycle tests are complete, then the parts go into fire testing. The unit will not survive. You start feeling sorry for the little bugger as if it has feelings. How do you decide which unit you send to its death? They do, actually, all look alike. So, reach in the box and grab one.
Then you check your e-mails and someone has asked you about a factor on the current test. "Are you checking temperature? It was never designed for frequent, continuous cycles. The temperature could rise and alter the results."
Ahhrrrggg! You knew you forgot something. You drop an e-mail to the test director at 10:30 at night. Within seconds, you have a response, "We'll get a thermo couple on it first thing in the morning."
Now you wonder if there could have been a temperature rise that could have done damage with all those repeated cycles. Is the test valid? Is it going to fail because you didn't think of the temperature because you were only concerned about getting the test complete as soon as the part operation will allow?
Morning comes without a word from the testing team. Noon comes and goes. You want to call but you don't want to be a pest. Finally, it's afternoon and you decide you will give it an hour. You get a phone call from the fire testing group. You talk about the tiny details that are required to make sure that there are no unknown hazards that will pop up in the test like toxic vapours or sudden explosions. Then you realize it is too late to bother the other test team.
You wait. You get busy. You assume that no news is good news. You don't call on day three of testing.
Then, you are at your customer's doing a trial fitting and your phone rings. It's the test director. "We have finished all 5000 cycles with no sign of wear. The temperature never rose more than 5 degrees above ambient. Everything is great." At least that is what you think he said as your phone cuts in and out and the sound of the drill in the back ground is drowning out the parts that the phone is allowing through.
Two days later the test results arrive. Yes! That is exactly what he said. No issues what so ever. No leaks. No temperature rise. No loss of function. No time delays. Everything is exactly as it was designed to be.
Suddenly the answer comes to you. Send that tough little bugger up to the fire test. He can handle it!