Electroplating issue

[D.T.]

I am having a hard time figuring out why our titainium heaters in our electroplating tanks are plating up. It's a copper plating line that uses 500 amp, 4 VDC power supplies to each plating tank.

We tried grounding the heater grounds to the rectifier cabinet, but they are still plating up with copper. We are going to try a 4' ground rod this week. Heaters and rectifiers are fed with 480V 3 phase AC current. Conduit on the rectifiers is EMT, using the conduit as ground and the heaters use NM conduit with a ground wire.

 

[mdshunk]

Bath heaters plating up is almost always due to leaky heater coating. These are teflon coated heaters, aren't they? We never had much luck with bath heaters that weren't coated. The teflon coated heaters are the solution to heaters plating up.

By the way, what's your fault current measure at the moment?

 

[D.T.]

My boss is not going to go for buying new heaters. I suggested this also, but they are NOT teflon coated, just titainium. We never really problem with this before. I don't know what changed. I was thinking a rectifier was grounded somehow and letting cathode current flow through the heater sheathing.

I had about 2 amps DC through the ground wire to each heater.

Thanks for a reply,
Dave

 

[mdshunk]

Well, the heaters have a limited life, so maybe he can get coated one's next go round. I have found the most economical teflon coated bath heaters from Process Technology, and their turnaround on custom dimensions is super-quick.

http://www.process-technology.com/processtechnol/fluorohtr.htm

 

[D.T.]

Process Technology is the place that we get all of our heaters. This is where we called and looked for troubleshooting info. I'll let my boss know, but it goes in one ear and out the other. Maybe I should use a hammer instead. My boss is the type that "lives off the land" and doesn't spend money unless absolutely necessary.


This is what we are currently using in Titanium (getting plated up):
http://www.process-technology.com/processtechnol/mots.htm

I think we should use this type of heater. We do in other tanks around the plant.
http://www.process-technology.com/processtechnol/HX.htm

This might work, but it gets close to the anode baskets. Shouldn't matter though, it's coated.
http://www.process-technology.com/processtechnol/HXF.htm

This is what I tried first, what they said in the troubleshooting manual:

Usually caused by either a difference in potential between the heater ground connection and that of a DC power supply (rectifier) or contact with charged components within the tank.

Inspect for contact between the heater sheath and plating tank cathode, work or parts accumulation on tank bottom contacting the heater sheath. Isolate components as required. If caused by a difference in potential between the heater ground and the rectifier ground, connect the heater ground wire and rectifier ground wire to the same verified ground source.

Thanks,
Dave