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Feasability of using e coating to provide corrosion resistance on mating parts that slide on one another

2007

We are a manufacturer of block and pin style universal joints. This type of joint does not employ roller bearings. The bearing pins are solid and come in direct contact with the mating parts of the universal joint, therefore there is considerable sliding friction generated due to the transmission of torque through the joint when the joint is operating at large angles. We have a customer that is presently purchasing stainless steel universal joints from us for an outdoor application. They basically are using the joint as a clevis, it sees limited use but needs to be capable of standing up to the elements. In an attempt to reduce cost they are now asking if we can provide them with a product made from 10/35 or 10/45 steel with e coating applied to it? The finished dimension tolerances specified are quite tight so the thickness of the coating needs to be uniform to enable us to make changes to the machining dimensions to accommodate the coating, as the finished dimensions are to apply after coating. My questions are as follows; If we were to have the universal joints e coated after being assembled would the coating penetrate in between the mating surfaces? Can the thickness of the e coating be controlled and if so to what extent, tenths or thousands of an inch? Typically how thick do you apply e coating? When e coating the assembles joints will the coating bridge between the mating parts causing the joint to bind up? As you can see I am trying to determine if this is a feasable option for this application.

Thank for the help,

Bill McCombe

Bill McCombe
Product designer - Springfield, Massachusetts

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Coating an assembly with moving mating surfaces is ruled out. They will jam.

To the rest of your question, there is a simple answer - The taste of the pudding lies in its eating. Since you are only changing the MOC and not the manufacturing process, make a trial lot and get it E-coated. You will in any case do that too. Better sooner than later.

But to put your mind at ease, you can control E-coat to ± 2 to 3 microns. Typical coating thickness is 20 microns.

Gurvin Singh
Mohali, Punjab, India
2007