Auditing New Coating and Plating Solutions

By Ian MacMoy

There are constantly new plating, new coatings and surface solutions coming to the market. It seems like every three years there is a contender. The question is are they any good? More times than not, the coating is hype rather than substance and the testing supporting it is not always ISO. Another issue is that the solution was manufactured in a lab, rather than in a production level facility. The problem with that, is Anything can be done in a lab, where you have time, and tools to get that one sample right every time. In a production setting, is where the variables come out, or the half attempts and inconsistencies show up. 

Why Change

We change formulas for many reasons, nothing is constant. Cadmium was doing great, until it was classified as a ROHS, same goes for Hexavalent chrome. We see other variables heading our way as well, Hydrogen Stress Cracking, Rare earth element shortages, cost of stainless, application thicknesses in dimension of threads, inconsistencies in Coefficiency of friction. These are just a few of the issues that have caused us to take a second and third look at our current solutions.

Testing New Solutions

Testing solutions should be something we leave open. So that anyone with a new solution can follow a know coating specification test in order to compare their new solution with all previous solutions, an apple to apple comparison. It is obstinate to think that the solution we have today will be the solution of six years from now. We should think like mechanical and material engineers and constantly look at new and better materials. Usually there is a number of tests we have to cross examine and compare with and even then we find out that the process needs to change, or that it cost too much in comparison. There are many different things that could change the outcome. About twenty years ago, we had the stainless steel test. We compared everything to trying to reach the corrosion leave of stainless steel.

Salt Spray Test

ASTM B117, is not the only test! Just because your product does well in a lab test , it does not mean that everyone should rush out and buy it tomorrow. There are many questions to ask, such as what is the process? Does that process include acids, extreme thermal heat, long durations of bake out, is it costly, where is it done at, can I get it in red, will it rub off in a cardboard box, does it incorporate hydrogen stress cracking? There are so many more questions than salt spray hours, or what color does it come in. The best thing about ASTM B117, is that it is a highly comparable test, due to its use.

Lab results

A product that is made in a lab, rather than in production, are two very different things. One of them is studied and built in a lab, where failure is not recorded, only the final outcome of the product is. 

In production, we take into account all of the internal non-conformance which slow down and add cost to the product. We measure the rate of correction and how it effects the bottomline, along with time frame and deliveries. We work with other substrate materials, lubricants, variations to our own specifications, real life.

Being able to create a 25 year life cycle solution in the lab, is (easy)! I have done it myself and I have seen it done about five different ways, BUT(!) being able to take that creation from the lab to production , is a totally different thing. 

Controlling the Variable

The variables tend to mount up when you are doing multiple parts at once. Dimension, thickness, material, chemical strength, or electrical strength, line of sight applications, thermal indifferences of thermal applications and cure rates. No matter what the application is, there will be variables associated with the process. The best thing to do, is have a technical authority, who knows the variables associated with the large scale production of that process and can account for it. Such as what do you do if you do not get the correct thickness inside the threads? A NCR action plan, should already have been written for any application.With some applications the variables are too great, and too meticulous to be seen in large quantity. This is the usual issue we see with superstar coatings. The inventor takes the time to do everything right and the process gets dumb down every time it is handed off. Millions of dollars, ok probably hundreds of millions of dollars have been spent on coating and plating application facilities, only to have them fail, why?

“The product was wanted and needed more than it was tested."

Production of the coating and/or plating should be completely witnessed and judged, by first article being picked from a production run. Not something that is dolled up and handed to you for testing. Anything else is a lab sample and has been hand picked, by the lab scientists who created it.

First Article

This is very important, the process should be something that you see the entire way through, not something that you see at the end and you do not know how many times they had to recreate that sample to get it just right. Not only new solutions, but anytime you are auditing a facility, you should ask them to produce a sample set of that process and witness its full production. Remember, there is no such thing as perfect/ 100% in coating and plating, there are always some errors that have to be adjusted for in production. 

Testing

There is a wonderful company that I have had a lot of luck with in the past and they have no idea who I am. They are an ISO approved lab where I send all of my friction testing, wear testing, fracture testing and hydrogen embrittlement testing. Miami Valley Materials Testing Center, www.mvmtc.com A list of testing should be agreed upon at the very beginning, or an apples to apples comparison test agreed upon. I have been through many first article tests, where the testing changed to suit the favored result. Naming testing up front allows other to provide a comparison test and it controls the premise and the narrative of the testing.

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