I was doing a modest house fix-it project and making slow progress, largely due to my time- and material-wasting errors in cutting and trimming. So I followed the principle that when things aren't going well, the best thing to do is stop and think.
I realized that the problem was simple: I hadn't taken the time, early on, to build a proper cutting fixture for the special angles and lengths I needed.
I should have known better. All my engineering experience, and exposure to many other design, development, and manufacturing engineers, has demonstrated that good fixtures and jigs are key to consistent, reliable, and efficient results. Sure, it's impressive to lash something together quickly to verify an idea or concept, but it takes a proper setup to know for sure, and to carry through to efficient production. If you can't reproduce the setup and results on another circuit board or system, then maybe what you think you have is not what you do have.
These fixtures can be electrical and mechanical. They hold boards in an established position with respect to off-board signal I/O and test instrumentation. They ensure mechanical alignment and placement doesn't skew results. They reduce set-up time when you have to build and verify additional prototypes. They are essential to final assembly and test speed and accuracy. A properly planned and built fixture is a solid sign of conscientious and thorough engineering craftsmanship.
Unfortunately, given the time pressures that engineers face, it's too easy to skip these steps and rig up something that works, at least once. And it's also unfortunate that the important role of the manufacturing engineer in developing assembly and test fixtures is often overlooked or minimized.
Do yourself a favor: if you have any doubts or need to be reminded, watch the series “How It's Made” on the Discovery Channel or segments of Mr. Roger's Neighborhood on PBS. Whether they are showing a high-volume toothbrush production line, or a huge earth-mover assembly area, you'll see how fixtures are as much a part of engineering craftsmanship as the design itself.