I agree, Rob. You have to give credit to Glenn, especially considering that he said: "the chips were slightly skewed, but within specifications." In other words, he chased down the solution to a misplacement of 1/250th of an inch, even though it was already in spec.
The best example I've heard of this, Island-Al is from a process plant. Apparently they laid off so many workers that there was nobody left who knew how to turn off the plant. That may be an urban myth, but even so it makes a point.
Good observation, Chuck. That shows just how precise it needs to be in order for it to be "right." So you have to hand it to this Sherlock Ohms to correct a situation that was so very close and "within spec."
The loss of experienced engineers is most tragic indeed. My boss says (thinks) we can get replacements easily. I have seen examples of these replacements firsthand and have yet to be impressed. One can hire poor engineers and technicians for ten cents a pound, and they are overpriced. Great ones are cheap at one hundred dollars an ounce, but are difficult to find.
In my experience engineers and techies are one of two flavors. The first are hourly employees who think only of the paycheck and watch the clock. Most belong to a union but I have no problem with that. The second are the guys who think only of the problem(s) at hand and are somewhat mystified that somebody keeps putting money in their checking account. In the late 60's accountants in the company I worked for kept calling me because I seldom cashed my paychecks. Direct deposit later fixed this problem. Last Sunday I received a PDF manual on some equipment we were having problems with. This vendor went into work to find, and send me, the documentation. He is one of the second flavors.
Parado was exactly correct with the 20-80 rule where 20 percent of the people perform 80 percent of the work. In the long run the 20 percent earn much more money but usually find little time to spend it. Of that original 20 percent, twenty percent of them are the true Golden Child ones.
That was a while ago, but I think the brake pad was a rubber piece on a pivoting arm. The brake does not hold the rotational orientation of the nozzle - inherent friction in the assembly does that. The brake holds the nozzle still from spinning until the theta 1 meshes. There is very little friction wear in the braking action. The theta engagement is a steel V-block that nests into a matching V-slot in the steel nozzle. The wear that does happen is the V-shape of the block, from the vertical engagement about 10 times per second.
Talk about getting things just right: It's instructive to note that placement of the surface mount chips was within 0.1 mm across one inch. Since a millimeter is 1/25th of an inch, it means that these chips were being placed with 1/250th of an inch...and this was unsatisfactory.
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