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Removal of Baked on Powder Coating from the bores and keyways of pulleys

2005

I work for a major manufcturer of Transport refrigeration products. The problems we often encounter affect our machined pulleys (we make several thousand per year) after they have been powder coated. The pulleys are machined and the keyways are broached at which time they are hung on pins (through the bore of the pulley),plugged with silicone plugs, and then powder coated. The problem is that we often encounter seepage into the bore and keyways of the pulleys which adversely affects the way they fit on the shafts on which they are intended to fit. We are currenty using a wire brush to clean the bores and filing excess paint from the keyways when necessary. A problem that arises as aresult of this (besides rework)which can become an ergonmic concern is the fact that sometimes if the operator of the wire brush gets to aggressive then our bore sizes can be affected. I should add that these pulleys are made out of malleable gray cast iron. My question. Is there any plug, chemical, or other method we can use which will either eliminate the seepage into the bore or ifnot at least make cleaning them out after the fact easier?

Regards,

Mark D. Marisch
Transport Refrigeration - Grand Island, NE, U.S.A.

Mark, rather than spend all the time and effort masking the pulleys so you can protect the machined areas, my suggestion would be to clean, pretreat and powder coat the parts prior to machining. After the parts are powder coated, handle them carefully and machine the bore, keyway, and set screw areas.

Roy Nuss
Trevose, Pennsylvania, USA
2005

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