Metal finishing Q&As since 1989

-----

Use of pulse rectifiers for acid cu and nickel plastic plating

2007

Hi,
We have been into electroplating plastics(Cu, Ni, Cr) since the past 35 yrs. We are currently setting up a new unit for the same. My query is would it help in using the pulse rectifiers in place of the regular big bodied rectifiers.
My thinking is that it would help me achieve better grain structure, energy saving and space saving.Of course there is a difference in price, but is it worth it? What are the drawbacks of using pulse or other electronic rectifiers.

Rahul Kakkar
- New Delhi, India

---

I think there is a little bit of confusion in your posting Rahul. The smaller rectifiers you refer to are called "Switchmode" rectifiers. Basically what happens is by converting the input frequency from 50 or 60 hertz to almost a thousand times that much, the transformers become miniscule compared to old style rectifiers, so the whole rectifier is tiny. Ripple is also greatly reduced; they probably are right for you.

"Pulse plating" rectifiers can be switchmode, but are more frequently linear technology rectifiers. The "pulse" refers to the output, which deliberately pulses instead of being a steady DC. There are plating advantages such as denser, more level plating, but they represent a whole new variable to tame so they are usually applicable only in high technology applications and are usually energy inefficient. And to my knowledge they are not used on chrome. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

What are the processes to electroplate chrome on polyamide (PA) and polypropylene (PP)?

Ricardo Kanitz Damasceno
- Farroupilha, RS - Brazil
2007