Bright Dipping Process of Lead Free Brass Balls Gr200.

[tekno9000]

We bright dip lead free brass balls (Gr200) as one of our process. The process is:

1. Degrease in soap solution with ultrasound.
1.1 Rinse in water.
1.2 Dry in centrifugal dryer.
2. Dip in 900 ml Sulphuric acid + 450 ml Nitric acid + 650 ml water and 2 grams of NaCl (salt).
3. Rinse in Deionized water.
4. Rinse in alcohol.
5. Blow dry.

The problems we are facing are that we observe white spots (salt?) on the balls which create quality issues down the line for our products. The balls also look rough (pitting on the surface).

Plating and allied processes have not been our strong points, nor do we have expertise on the subject in house. Now we have resort to 100% inspection of the final product and this is killing our productivity. This is going on since one month and we were able to finally pin it down to this bright dip process.

I will highly appreciate if any one experienced in this field can help to determine if the process and the concentrations are right.

Please feel free to ask me as many questions as you like so that I can look in my process which I might have missed during my process observations.

Thanks.

 

[silentrunning]

Did you omit a rinse operation between #1 and #2?

 

[tekno9000]

Oh, I missed the rinse and drying operation between 1 & 2. Thanks for bringing it to my notice.

 

[silentrunning]

There are several makers of bright dip products listed on the net. I would look to one of them for advice - unless you are process bound by your customer. They may have a safer, more effective method for you to use.