Selective anodising 1

[var10]

Recently we have shifted from aloding our parts to anodising. This means that there might be issues with grounding the part. I heard about something called selective anodising, which is to mask or cover certain areas to prevent them from being anodised. I have contacted my supplier and they reckon the mask keeps peeling off during the electrolytic process. I wasn't able to find any information about what material should be used to mask during anodising. Not many coating specialist here know of selective anodising (probably it has less demand). What should I use to do this process?

Thanks in advance.

V.

 

[TomDOT]

What are the exact conditions the part sees during the process? Find a pressure-sensitive adhesive (tape) which can stand up to those conditions. Alternately, find something like a grease or wax which can stand up to those conditions and you can vapor degrease and/or melt off after the process.

Impractical at scale, but in college, I did selective anodizing of titanium by hooking up the electrode to a dampened paintbrush and brushing titanium in areas where I wanted the anodizing. I also adjusted color by adjusting voltage.

 

[mcgyvr]

We have used these with no problems during clear and black anodizing (vendor is using an alkaline etching process)

http://www.epsi.com/ad12-series-green-poly-discs

But you must make sure the surface is clean and then you need to really press them on and rub them into the surface to ensure good adhesion.
Our plater would actually use windex to clean the local surface then pick up and attach the masking using a exacto blade to ensure placement and then used a plastic roller or burnishing stick to press them on firmly.

An alternative is spot-facing after finishing.. (and actually turned out to be cheaper due to labor involved in applying the masking/demasking).

Its not a cheap process though.. It turned out to be around $0.50 per masking spot or $0.25 to spotface.. (volumes of 100-250 pcs per lot)

 

[berkshire]

Google "Chem etch resist", you can use this for masking off areas for selective anodizing.
B.E.

You are judged not by what you know, but by what you can do.

 

[var10]

All that I found was Linered electroplating and anodising tape. Is that what you meant?

 

[TVP]

var10,

Have you checked out this article:

http://www.pfonline.com/articles/masking-for-surface-finishing

It lists a number of different methods for selective plating/anodizing. One process with which I am familiar used a flexible, elastomer material for the mask. I am not sure if it was plastisol or something else like polyurethane.