The authoritative public forum
  for Metal Finishing since 1989
  

  -----

What is zero chloride acid copper bath?

we are manufacturers of rotogravure cylinder.For this we are using base metal is mild steel first we were doing cyanide copper plating about 15 min then we go for the acid copper plating which contains copper sulphate ⇦ this on eBay or Amazon [affil links] 200 gms/ltr,sulfuric acid 55 gms/ltr,chlorides is zero and anodes is non phosphorous copper nuggets.In this bath we are using a additive for hardness to get 200 vickers.then we go for the electronic engraving.Now I had a problem with structure of the cylinder.If the strcture is not proper
when doing engraving it breaks.

Hari prasad Kurakula
Product designer - uppal, A.P, India
September 9, 2008

Do you mean the stylus on the engraver breaks?

Andrew Burt
gravure cylinder maker - Birmingham, UK
September 15, 2008

---

sir,
exactly sir,when we were doing the stylus was breaking.This problem happens many times and my operator said that if the structure of cylinder not proper causes the same problem.What I have to do to get good results.

Hari pradad
- Uppal, a.p, India
September 16, 2008

---

September 17, 2008

Hello,

I recommend you the following test procedure to improve you deposit a ductile copper which is important for proper engraving and increasing diamond life time.

- Make a ballard skin with a thickness of 80 - 100 microns
- Bend it in radial and axial direction (it should be bendable 2-3 times before it cracks). If the ballard skin is cracking earlier than you could have the following problems:

1.) Overconcentration of hardening additive
2.) chloride contamination
3.) Too many organic breakdowns

When did you do the last active carbon/hydrogen peroxide treatment?
How is your actual dosing?

If you detect that might your ductility of the copper deposits are fine, another reason for low diamond life time might be also an iron contamination. Which only can be removed by dilution or preparing a new bath.

Recommended concentration:

210-240g/l Copper sulphate
60 - 68g/l sulfuric acid (sulfuric acid acts like a grain refiner and should be also considered forcing these kind of problems)
Temperature: 28-max. 32°C.

Best regards,
Dominik

Dominik Michalek
- Mexico City, Mexico

Thank you sir for your valuable reply.But I hav one doubt sir how much chlorides are allowable in bath(in ppm) and how to analyse the chlrode in laboratary.I did carbon/peroxide treatment monthly one time it is enough?.How to reduce the chloride concentration in the bath presently I was doing silver carbonate treatment to reduce chlrides it is correct?.This treatment is very expensive for me,any other treatment for reduce chlorides.

Hari Prasad
- Uppal, A.P, India
September 20, 2008