Q. I am struggling to get my first-pass yield up and my rejects down. We seem to have the ability to get out good parts, but we are not as consistent as we need to be. I think our problem may be related to our racking. Some of our racks have a lot of buildup on the contact area, and rack maintenance is generally not perfect. We have some bent racks and we use some hooks that do not hold as many parts as we could fit on the line with better racking. Is there any way to qualify the impact of racking on the powder coating process? D.J.
A. Yes. The costs can be evaluated to determine the difference between an optimum racking scheme and a questionable racking scheme. You need to evaluate what your throughput could be if you had proper racks and compare it to how you run it now. You can build samples to test theories and compare the defect rates to any other rack method. If you can quantify the current rack capacity and quality, you can compare them to any other rack option. It is simple math to evaluate the number of parts per foot, and the number of good parts versus bad.
Many companies waste a lot of dollars by using sub-optimum racks because they do not want to invest in tooling, they do not want too many different rack designs around, or they just do not even evaluate it at all. Evaluate the options and there is a good chance you can improve the throughput and reduce costs by using the right racking scheme.
Infrared cure is gaining increased attention from coaters as a result of shorter cure cycles and the possibility of smaller floor space requirements when compared to convection oven curing.
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