Need some help - how can I etch with a high level of clarity?

[Nick Koprivica]

Hi everyone. I was approached by a potential customer who has a unique application. He wants to etch designs onto small circular pieces of a material and then shine a light source through them to project the image.

It's similar to one of these laser pointer sets where each attachment projects a different image:


The only thing is that the projected image is magnified a lot so the edges need to be crystal clear. I tried etching on glass and acrylic but the edges are too grainy.

Does anyone know of a material I can etch an image onto and have all the clarity and detail there when it's magnified? The pictures are 3/8" diameter.

I was thinking of using Thermark LMC12 marking solution on thin sheets of polycarbonate plastic.

Can anyone help me out?

Thanks,
Nick

[Dan Hintz]

You need a substrate that will not be easily marked with the laser, covered with a material easily removed by the laser. I might try a thin sheet of plastic, like a drafter's vellum, painted black... etch away what you don't want. I'd also consider a few light light light coats of black on glass, hit with several light light light passes of the laser... maybe even a vector pass around a raster work to make sure the edge is nice and crisp.

[Tom Bull]

You need to consider what the temperature range will be. Somewhere in the ancient past here on smc there is a thread on doing this for theater lighting.

[AL Ursich]

I don't believe a laser pointer will generate much heat if I am right...

Sounds like a job for acrylic sublimation on clear.....

Or Water Slide decal....

AL

[Viktor Voroncov]

If possible use 1" lens.

[Jim Coffee]

I've never done what I am going to suggest.
Perhaps the laser is not the machine with which the design should be created. Consider instead having the design(s) photo printed onto a transparency type of material. An 8 X 10 transparency could hold hundreds. Then use the laser to cut the designs into the proper shape for insertion into the laser pen.

So the workflow would be:
1) Art program to create the artwork from which the transparency would be made.
2) Create transparency (photo lab).
3) Establish proper registration in the laser and cut out.

[Martin Boekers]

First, how is the resolution of your images?

You can check by maginfying it. It you see rough edges you will have rough edges.

If that is the case you need to convert it to vector.

What resolution are you lasering at? I would test at the highest setting with just enough power and speed to remove the coating.

On acrylic, are you painting it black first to withhold the light?
if so, you might have to try other paints so the edges melt more uniform.

Also, you may check with a local theatrical company to see what they use in low heat situations.

One more thing would be to print on a velum material, check with screen printing supply houses. There is a velum specially designed for this process. Then after you print to it there is a spray that darkens the black areas. This is used by many shops to make printouts that are used to make their screens.

As with anything printed, be sure to ask about durabilty and life of the product.

Marty

[Rodne Gold]

You will never get great edges on a big magnification if you raster engrave , it works with "dots" - where you might get better results is to raster engrave and then use a vector to outline the etched areas and use low power to vector engrave these. This will clean up edges.
If your machine has a tuning or a way of aligning the matching of the left and right firing of the laser as the head makes passes , then use that as well.
Using a very high DPI when raster engraving will also tend to smooth out outlines.

[Nick Koprivica]

Thanks for the tips everyone.

I'm having some success with sheets of transparency film spray painted black, but I'm still not getting the clarity I'd like. I think it has to do with how small the artwork is. I'm raster engraving everything at 1000 dpi.

Rodney, I like your idea with using vector mode to clean up the edges. Do you, or anyone else, know how to convert an image into a vector outline in Illustrator?

[Dan Hintz]

Nick,

I suggested vectoring first

Assuming the image is B&W, Illustrator CS2 and up has a feature called Live Trace that should be easy peasy to use.

[Mike Null]

I would think the photo-resist process such as is used for sandcarving would be sharper,speedier and less expensive.