Need help sourcing translucent plastics.

So I’m in charge of producing two prototypes, that call for a translucent piece of plastic that will be milled and polished out. Thing is, I don’t want just a generic smoke or tint, I want something REALLY dark, as it will be milled to about 1mm thick in front of an OLED screen. I’d like either jet black, or really dark blue. I’m having a lot of trouble finding anywhere I can purchase plastic like this, it seems like most plastic suppliers just have the generic “smoked” or “tinted” acrylic sheets, that’s it.

Anybody have any ideas?

transluscent … as in, semi-opaque?

or

transparent … as in able to read text/video through?

Ref.:
http://www.plexiglas.de/product/plexiglas/en/products/solid-sheets/aircraft-materials/pages/tints.aspx

Might give these folks a call and see what they can do; they offer color match capability.

Sorry, yes, transparent, though I think when it’s machined to 1 mil even translucent would work.

regardless of how dark it is, it will be brighter in a thinner section … you might consider applying a “tint” mask over the thinner [1mm] section if it’s too bright.

Like “tail light” paint: VHT Nite-Shades™-- Specialty Products

Stumbled across this method of polishing transparent machined PC recently that is both cool and terrifying. Flash point of boiled solvent anyone?

… and one guy standing outside in case of any accidents…

Way cool! But I wonder why it take two guys to do this? The guy holding the hose could be replaced by a fixture.

OSHA obviously isn’t a concern wherever this is…

That’s really hot. I would think it would be far safer if the hose was being clamped to something too. Maybe there is something before or after that he needs to do?

I second Lew’s suggestion: tint your plastic afterwards.

There’s a lot of wrong going on in this thread.

Vapour polishing or honing, same as flame honing, is really attractive but should never be done as it depolymerizes the surface area creating a scab-like effect that induces tremendous stress in a small area. Vapour / flame polishing produces a beautiful optical surface but over time the part will develop internal cracks. The time though is unpredictable, weeks to many months. Therefore, vapour / flame polishing is acceptable for short life purposes, i.e. a prototype, photography.

You cannot mill a clear polymer down to 1mm thickness, temperature and or cutting forces will distort the material. Probably someone has tried, maybe even achieved success, but on a production basis the part scrap rate will be too high. I would assume commercial machine shops would reject this job.

Optical display lenses like you describe can be done by any quality label, membrane switch and display manufacturer. It’s what they do daily, they have numerous thin optical plastics in a rainbow of colors, tints and finishes, and typically laminate numerous layers to build up required thicknesses including multiple stepped thicknesses over display lenses. On many mobile phones the fascia is made this way then insert molded to add further details and surface shape.

There’s an amazing transparent color chip set by Pantone… I’ve only seen it in one studio but it was amazing. Each chip is in a pantone color, or grayscale, with varying thicknesses, so you can see how it reacts with more of it for light to go through. I think there was varying percentage opacities too…

Packaging designers might have it, especially if they do structural drink containers… or maybe a local university or modelshop and you could take a look. A modelshop might have their own transparent color chips for specifying too

With something like that, you could specify exactly what tint at what thickness you want. Would be a good start if you were ordering plastic sight unseen… if you could find a source like that.

Another option is to make a urethane mold of your target part, which would spits out about 20-50 molded parts, and try different opacities to test the it out

For translucent plastic (acrylic) you might try Inventables.com. Large range of colors in small sheets that ship from stock. They have dark colors to pink bubble gum to radiant.

See: World's Easiest CNC System for Machining | Inventables

Hope this helps

We used to vapor polish parts at a company I used to work for. We just used a tea kettle on a hot pot inside the paint booth. It only takes one person to do the polishing. The kettle was kept hidden for the times when the OSHA inspector stopped by. :open_mouth:

Wow sonicboom68, great link, thanks!