I read that the position which failed held the batteries in a "canted" position, but what was the precise reason for the test failing? Did the canted batteries fail to make contact at all? Was there poor contact resistance, or what? The observation and deduction is smart, but I feel I am left hanging.
Most any Quality Manager worth their salt will run Gage R&R (gauge repeatability and reproducibility) on their test and verification people and equipment on a regular basis. When you don't do this, you haven't a clue as to what you're producing. You need to understand or get get full control of all variables in your inspection processes.
Our people are amazed when we report the source of variables and variation in our most basic inspections (like using a mic or caliper). It's a real eye-opener for most people outside the Quality field. Managing Type I and Type II inspection errors is a fundamental problem in most every company.
The 'When you assume...' phrase is common, but useless. Everybody makes assumptions. Assuming the rejected parts are actually bad, or assuming the rejected parts are really good is a beginning of troubleshooting. The real trick is to know and realize what your assumptions are, and be prepared to revisit them when troubleshooting doesn't agree. During a light-hearted conversation I was asked of I knew what happens when you assume. I replied 'Did you assume that I was listening to you ?. Of course you can't say that to your manager.
The author did a good job isolating the problem. I think perhaps the other folks were not so experienced in troubleshooting. I'll never forget as a young tech making an assumption that wound up delaying a resolution to a problem we were having. I don't remember what the problem was but I sure remember my angry boss pulling me into his office and writing ASS U ME in large letters on his white board. He then asked me if I knew what happens when I assume - If you look closely, I am sure you can figure out the rest of the story...
That happened in 1990 but is a lesson I carry with me to this day!
That's funny tekochip - I had the opposite problem. When I was a test engineer and parts started failing, everyone always wanted to point to the test set. I always kept calibrated "golden" units around so that I could verify tester operation. I made sure my golden units included passing units at both ends and the middle of the spec as well as rejects. Most of the time that would satisfy all involved that we needed to look at the parts themselves...
That is very true. There is no way that time would have been allocated for troubleshooting during production. In fact several of the gizmos I designed for in process trouble shooting had to be carefully designed such that if production supervision called for their removal they could be removed on the fly without interruption to the line flow.
Another variable may have been your testing the rejected parts during the operators' break time. If you had instead tried to take 'production' time to do the testing you may not have been allowed the time you needed.
The rate at which the cells were produced provided very little time to troubleshoot, and policy was to make up the shortfall where suspect cells were concerned, quarantine the defects and pick up on their disposition later. For some reason management left me to my own devices and I could work at a rate that suited me instead of being under pressure.
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