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"Plating Shop Restructuring"
August 2, 2017
Q. I work in a plating shop that has been around for nearly 30 years. The owners of the company are trying to bring the company to a new location in order to keep quality better controlled. That being said, the current process of plating is not yielding quality in a productive or efficient manner. Lots of rework is being required into the process. A remedy being used to achieve "conformity" on bright tin plating is to scotch brite the surface after plate to make them more cosmetically appealing.
I have been assigned a somewhat daunting task. I am being asked to design a new system from the ground up. I want to have better controls of chemical adds and a more systematic way for for maintaining consistency about plating the work.
A supplier for rectifiers asked me what voltage requirements I need in order to get the most economical unit for my use. A struggle I'm experiencing is knowing what that is? I understand the amount of anodes in my plating tank is going to have a maximum rate of deposition per current applied to work. However, there are also resistances that will affect plating efficiency (chemical conductivity, cable from power source to bath).
I'm struggling with wrapping my head around the task and needing a good place to start in order to get this project underway. Any help would be appreciated.
Buyer - Fort Smith, Arkansas
A. Hi Aaron. The reason this industry has consultants is precisely because such tasks are daunting the first dozen times you do them, and it's best to have someone guide you and help you avoid mistakes :-)
Although plating is ruled by science, many of your questions (like the required voltage and amperage of the rectifiers) will be determined empirically from prior experience rather than from first principles. Yes, the plating solution does have resistance and you could theoretically determine the required voltage with electrochemical modeling software, but it's generally just not practical to start that way. And the required/allowed amperage is determined the same way, i.e., not from diffusion equations but from the knowledge that, for example, you'll be doing your nickel plating at about 40 ASF.
Please see our on-line library article "Plating Shops for the New Millenium" as a general start on not making some of the mistakes again that may have hampered you for 30 years. Best of luck.
Ted Mooney, P.E. RET
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finishing.com - Pine Beach, New Jersey