Blistering Problem on Zinc Die Casting

A. Yes, it is all of those things and more. You will need some help on the ground. I would start with adding proprietary vendors of plating chemicals, and then get technical help from the people who sell you chemicals.

A. Dear Mr Deville Yiu, Your question reminds me of the story of a visitor to the Boeing factory who asked a simple question 'How do you make airplanes?' Whilst Mr. Pullizzi has rightly pointed you in the direction of the Chemical Vendor, I would also advise you to get hold of a person with considerable hands on experience in plating Zinc diecastings to establish your line. I don't think that Zinc plating would help much.

A. Hi Archana. I assume the caps are diecast zinc? What you are plating them with, and where on the caps doesthe blistering occur? Blistering occurs when there is no adhesion or poor adhesion, and there should be excellent adhesion. Rack marks are part of the plating process; it sounds like you should be using plating racks rather than individually jigging the caps with wire. Good luck.

A. Hello dear Devill yiu and archana

plating on zinc base die casting is not easy compared to other metals, and main two reasons of blistering on zinc base die cast components:
1- process blister :-this type blister is created during die casting process
2-service blister :- this type blister is created during plating service (delay blister :-after plating 1 day, 2 day or same day but it is service blister.

secondly electroplating process is not cheap. it is electrochemistry but now without blistering plating on zinc base die casting is possible but need some care like
1- proper zinc alloy composition
2- proper die casting process (melting temp./pressure /cooling time /releasing agent spray /etc.
3- suitable buffing polishing compound
4- buffing wheel and system and pressure during buffing work
5- suitable buffing compound remover
6- location of storage after buffing
7- do not touch open hands after buffing (need hand gloves)
8- after buffing the product is not stored a long time, maximum 24 hours. If possible do plating before 24 hours
9- proper metal cleaner
10- soak time and temp very important
11- ultrasonic cleaning
12- electrocleaning cathodic proper cd
13- activate suitable fluoride base
14- high speed cyanide base cu (important bath condition /temp./cd and choose right anode OFHC cu (oxygen free high conductivity)
15- acid cu plating (important bath condition and temp. chilling need,
16- nickel plating (important bath condition and operating
17- all rinsing steps are very important and carefully need.zinc is very sensitive metal and rinsing /cleaning steps/water break test is very important in plating process
18- if possible please use all steps use dm water
19- if possible all plating tank use with filter
20- use good company rectifier (minimum repels )
21- use hot air blower after plating
22- any problem after plating do you investigation need
check step by step first to last plating where problem and what problem (blister / peeling /pitting / etc.

A. Hi Deepak. In my experience they can't. Sorry, but very high quality castings -- free of porosity and coldshuts -- are essential for successful plating. There is no way around it.

Regards,

A. Hi Vinayak. It is quite difficult to reliably plate zinc diecastings as you will read on this page. If your only problem is that they are not shiny, count yourself skillful and/or lucky :-)

I was not even aware that diecastings could be successfully plated with acid zinc.

Regards,

A. Hi Yunus. Kanjibhai has given us 22 possible reasons for blistering of die castings. But if the blister problem occurs before plating, it sounds like a diecasting problem which he covered in his first few entries. Are you doing the diecasting in-house or buying the castings? Tell us about your QC inspection please.

Regards,

Hi again. Any reader is welcome to try to help you, but I don't know much about diecasting. This site focuses on the finishing processes rather than diecasting; so, sorry, I'm not sure if we will attract the readers who can best help.

Regards,