Metal finishing Q&As since 1989

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Hard chrome plating of special purpose pistons /shafts - Startup

September 11, 2009

Hello.

I am Saumil. I am from India. We have just bought a factory to start manufacturing of C45 hard chrome plated piston rods of diameter 25mm to 150mm. The lengths of the bars will vary from 3 to 4 metres.

In the earlier plant (which was meant for big jobs), we used to hard chrome plate two piston rods at a time in a square tank of 1 metre by 1 metre using tin-lead alloy anode of diameter 300mm thereby leading to high power bills due to huge heating requirement.

Looking at our production demand, we are planning to hard chrome plate atleast 4 hard chrome plated bars at a time.

Now my questions
1) What should be the length and breath of vertical hard chrome plating tanks so as to enable production of 4 piston rods at a time? What I mean is whether a square arrangement of 2x2 is preferable or all 4 pistons in a row thereby making the tank a narrow one. In either case please mention the approximate length and breadth.

2) What should be the distance between the anodes and the job? I am asking this as I have heard from people that the bath solution changes from trivalent to hexavalent if one places the anode too close to the job.

3) Also, will I need a cooling system to maintain the temperature? I am asking this as the tanks are going to be smaller and the anode is going to be closer to the job. This need is not felt in my first plant as tanks are huge.

4) Also, should I polish or buff the piston bars post plating i.e. which process is better buffing or belt-polishing for better lustre post plating.

Thanks.

Eagerly awaiting comments.

Saumil Mehta
Start up - Mumbai, India

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September 11, 2009

What, you did not like my answer to posting 52995?
I see that you added some to it, but I will pass on answering the add ons.

James Watts
- Navarre, Florida