Topic: Redundant Testing Requirements

Interesting Conversation that happened recently though PF's Electrocoat Clinic. Any thoughts to add?

During our last E-coat Clinic we had a question titled “Why Those Redundant Testing Requirements?” The core of the question dealt with the requirement to run every new part through a series of tests even if other similar parts had already been tested and, in some cases, had been in production for some time using the same substrates and being made by the same equipment and processes. I asked for comments from our readers. Here are three of the responses we received.

“We need some standard guidelines!”
I would like to have common testing and eliminate some of the redundancy. We are a Tier 1, 2, 3… automotive stamper so we’re told different things by different customers. However, we usually hear that each part must stand on its own and pass validation testing. They argue that just because a panel passes that is no indication of how the part itself will perform due to a slightly different substrate, different oils, and more complex configuration.

Being a stamper, we are always caught in the middle of this argument between our coater and the customer. So what we would really like to see is some standard guidelines or criteria accepted by all parties so that we can put this argument to rest. M.L.

“It is a waste of time and money!”
Today, as we all know, the economy is in poor shape and we are all trying to survive in our industry. We implement lean manufacturing and many other things to reduce costs, and then someone wants to test a process that is and has been in control.

E-coaters are usually at the bottom of the chain in automotive as far as company size and recourses and are required to do these tests over and over again with the same result. We think testing to the ASTM periodically at our cost should be recognized by the end users as being compliant with all the individual specifications. Will the automotive companies at least get together and try to eliminate this waste of time and money in our industry? D.C.

“The OEMs feel they need to make sure all bases are covered!”
The standards are promulgated to control all situations under all circumstances to assure the the end customer receives acceptable parts.

There are so many different variables that affect the cleaning, pretreatment and coating process that it is almost impossible to assure the process is capable without performance testing to approve the overall process. The process involved includes the raw material processing and preservation at the steel mill, the processing, lubrication and packaging at the stamper and the cleaning, pretreatment and coating process at the coater.

The overall process is validated by the performance testing. If the steel supplier changes or the preservation being applied changes, it could have a negative effect on the coating process. Many times, the coater is a Tier 3 or 4 supplier, and although it appears that the processes for different parts from the same customer are identical, upstream differences could cause problems and hence what appears to be redundant testing could actually prevent the production of defective product and associated failure costs that far exceed the cost of the performance testing.

I would agree that, with identical raw materials and processes leading to the coater, performance testing is redundant. However, if the investigation is deep enough, the occurrence of actually identical raw materials and processes is probably rarer than it seems.

Using the automotive industry as an example, the cost of product recall makes the risk of not testing parts that appear to be identical (but which the large supply chain makes that almost impossible to verify) too high to consider in most instances. For this reason, the OEM requires that each different part be validated. The OEM can’t control the lower tiers of the supply chain well enough to be comfortable that there are no differences that would affect paint from one project to another. So the OEMs have to require the performance testing as evidence that the process chosen is capable of producing acceptable parts. Then it falls on the supply chain to control the processes to receive consistent results. R.P.

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