electropolish a plated plastic to improve surface finish? 1

[jrn11]

I have some plastic parts with an inadequate surface roughness. My colleague had the idea to get them plated and then electropolished, to achieve a really smooth finish. Has anyone encountered such a plating-polishing process before? I've only found info on plating or polishing separately, and not on using them consecutively.
Thanks for any help! I'm happy to clarify if something in my question doesn't make sense. I'm very new to this topic.

 

[CoryPad]

Usually plating parts makes them smoother because of the leveling action of the plating (especially copper).

 

[IRstuff]

Sounds like you should redo the parts. Plating and polishing is just not something that is warranted for presumably cheap plastic parts.

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

 

[MintJulep]

Plastic can be polished.

 

[ornerynorsk]

What is "really smooth" ??? Plating generally mimics the finish of the substrate.

Are your plastic parts molded, machined, printed, or other? Contrary to what irstuff has mentioned, many "cheap" plastic parts are not very cheap at all, and require plating as a critical function of the end use, but it sounds like you're more interested in surface finish. You've actually not given much information in your original posting to offer much in the way of helpful commenting.




It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[SnTMan]

Polishing a what?

 

[jrn11]

Thanks for the feedback. The parts are printed. I don't have a spec for the roughness yet, but we may even like to use it for molding optical components if possible. I am also just personally curious about this process (plating followed be electropolishing) even if it turns out not to make financial sense for this application. Or maybe it would never make sense for plastic parts. I'm not that familiar with plating and polishing costs.

 

[berkshire]

If you are electro polishing, you are using reverse current to remove some of the plating you already put on. Are you sure you want to do that?
B.E.

 

[HDS]

no

 

[jrn11]

I spoke to an electropolishing professional, and I got the impression that the amount of material removed would be purely a function of the thickness of the metal layer, not the height of the asperities or the thickness of the underlying plastic. Therefore, plating then polishing would exactly mimic the underlying plastic surface and would not improve the surface finish. I definitely could be misunderstanding, and I still think it would be an interesting experiment to evaluate the surface after each of these processes, but I don't have time for that right now.

 

[IRstuff]

That will depend on the size of the "bumps"; very tiny ones will get smoother, but large undulations will not be affected. Many field-dependent processes count on the increased field-density around asperities to accelerate processing in their vicinities, thereby smoothing out the effects of base layer asperities, or even asperities in the overlayer.

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

 

[MikeHalloran]

Consider vapor polishing the plastic.

For printed parts, don't expect miracles.



Mike Halloran
Pembroke Pines, FL, USA

 

[MikeHalloran]

It MAY be possible to print a blank for an optical part, then "hot coin" the optical surfaces by pressing them with a hot, polished forming tool.

I would not expect the process to be fast, and you may need a relatively insane amount of process control to get uniformity.




Mike Halloran
Pembroke Pines, FL, USA