Metal Finishing Masking Issues

ramiibrahim · Aug 14, 2017

Hello,

I'm new to the Forum, so sorry if this has been addressed before. We manufacture many parts that require masking during the platting process. We find that there is always an issue with the masking especially around features being left out. This causes either a lot of rework, or scrapped parts. We just scrapped 20 parts out of a lot of 200 that are $150/pc.

This seems to be a recurring theme. Does anyone else have this problem? How many parts is a reasonable scrap rate due to Masking? Has anyone overcome this issue with their platters?

Any feedback would be helpful Thank you!!

mneuro · Aug 14, 2017

Welcome to the world of sub-contractors. Plating seems to be an ongoing issue with a lot of people. The only way I have had success in fixing a problem is by going to the sub contractor while they are running our parts.

ramiibrahim · Aug 15, 2017

Hi mneuro,

Do you guys have masking issues too? Should I expect 1-2% scrap rate due to masking? Being at the sub contractor each time we want to run a lot is a non-ideal process.....

mneuro · Aug 15, 2017

Yes, we do have masking issues. It is hard to nail down a scrap rate. There will be stretches of time where there are no issues at all, and I have had lots that have a 60% scrap rate. Of course the plating company will only credit for the cost of plating so it ends up being a lot of lost time and material.

Can you do your masking in house? We do quite a bit of masking in house, and it seems to alleviate a lot of issues.

It is also a good idea to build a relationship with the plating company employees. We had one family of parts that was always run on second shift. I went to the plating company a few nights after work to see the process and meet the employees. Spent some time talking with the guys running the parts, and helping out a bit. Havent had an issue on that family of parts since.

Comatose · Aug 15, 2017

That sounds high, but it's hard to know, because we don't know if your parts are "don't plate this end of a flat plate +- an inch" or "plate in this pattern, the clearance from mask to no mask is .003" and the part is organic curves."

My experience with platers and anodizers is if you need something tightly controlled, do it in house and deliver it ready to dump in the bath. You don't want to bring plating in house (EPA mightmare, corrode your machines, fiddly etc) but masking is just straight labor at either place. The difference is you know what to look for before the parts go in the tank and the plater really doesn't.

hanermo · Aug 15, 2017

I really have no personal skill or experience..
but novel techniques might be worthwhile testing.

Could you plastidip them yourself ?
Or perhaps use powder coating ?
Or paint, using water soluble epoxies ? Common these days.

Any above for masking can come out, later, with suitable solvents.
If You prove it works, then test for non-harmful/toxic/non epa controlled stuff.

Or things like generic epoxy glues might work.
Something used to coat fuel tanks, for example.

Just pointing out that many many simple solutions might work well, depending.
If the plating is not hot, even a wax dip might work.

It might be possible, and really cheap, to laser cut plastic or thin-sheet stencils, for laying-on the goops.
Or leave the stencils in place, glued in, if the jobs repeat.

A metal laser-cut stencil might cost 3€ - 10€, vs a 50€ avg loss due to scrap.
Heck, they could even be intaglio printed.
And for 200€ or so in stuff, and 1-2 days you can make your own 20-50++ (100) ton intaglio press.

Or for 1-2k, a crap chicom laser cutter will cut your own stencils in many plastic-type-materials.
Depending on size, stuff, etc.

Certainly, if I was losing 3k$ in scrap more than once per year, I would buy a laser, after testing it with stencils cut by someone else.

Look for advice from screen printers, intaglio hobby printers, offset printers. Hobby guys are fine.
They can advise / show on solvents, cleaning, process, metal-substrates etc.
Maybe jewelry stuff.
Engravers.
Etc..

I would look for someone who knows / has done similar in one-off hobby stuff in your materials, and offer 200$ for "advice".
You would likely get a consultant for life, or duration of project.

And likely spend 90-96% less on chemicals, as the hobby guys will know that the brand name stuff "nnn" at 100$ per litre also comes from the pool store/pet store/professional cleaning store/construction wholesalers/marine industry for 10$ / gallon or 40x cheaper.

ramiibrahim · Aug 16, 2017

Thank you very much for the feedback.

hanermo said:
I really have no personal skill or experience..
but novel techniques might be worthwhile testing.

Could you plastidip them yourself ?
Or perhaps use powder coating ?
Or paint, using water soluble epoxies ? Common these days.

Any above for masking can come out, later, with suitable solvents.
If You prove it works, then test for non-harmful/toxic/non epa controlled stuff.

Or things like generic epoxy glues might work.
Something used to coat fuel tanks, for example.

Just pointing out that many many simple solutions might work well, depending.
If the plating is not hot, even a wax dip might work.

It might be possible, and really cheap, to laser cut plastic or thin-sheet stencils, for laying-on the goops.
Or leave the stencils in place, glued in, if the jobs repeat.

A metal laser-cut stencil might cost 3€ - 10€, vs a 50€ avg loss due to scrap.
Heck, they could even be intaglio printed.
And for 200€ or so in stuff, and 1-2 days you can make your own 20-50++ (100) ton intaglio press.

Or for 1-2k, a crap chicom laser cutter will cut your own stencils in many plastic-type-materials.
Depending on size, stuff, etc.

Certainly, if I was losing 3k$ in scrap more than once per year, I would buy a laser, after testing it with stencils cut by someone else.

Look for advice from screen printers, intaglio hobby printers, offset printers. Hobby guys are fine.
They can advise / show on solvents, cleaning, process, metal-substrates etc.
Maybe jewelry stuff.
Engravers.
Etc..

I would look for someone who knows / has done similar in one-off hobby stuff in your materials, and offer 200$ for "advice".
You would likely get a consultant for life, or duration of project.

And likely spend 90-96% less on chemicals, as the hobby guys will know that the brand name stuff "nnn" at 100$ per litre also comes from the pool store/pet store/professional cleaning store/construction wholesalers/marine industry for 10$ / gallon or 40x cheaper.

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