controlling depth of engraving

[Matthew Sullivan]

Hello all,

A customer I have is interested in creating his own board game. It's like a hybrid of scrabble and monopoly, sorta neat. However, this is my problem. I would like to engrave approx 3/64" - 1/16" down into 1/4" acrylic for the pieces to fit into so they don't shake loose like on a regular scrabble board. The pieces are about 3/4" square. So here is the issue, I can engrave down that distance, but it leaves LOTS of lines back and forth from the laser. I've tried engraving at 1000 dpi 1000 ppi, 500 dpi 500 ppi, 333 dpi 333 ppi and 166 dpi 166 ppi. Not sure if this is how it was supposed to be done. It only really achieves the depth at 1000 dpi and 100p ppi 100 sp 100 power but the problem is these lines in the engraving. Is there any way or settings that you know of to more or less "engrave out" an area of acrylic so the engraved out part remains clear and not so frosted and perhaps even without lines?

Thanks a lot in advance

Matthew Sullivan

[Bill Cunningham]

My experiance is you 'won't' get rid of the lines, even if you do the area a second time pulling it way out of focus to smooth out the cuts.. If it has to be clear at the bottom, I would just cut right through the 1/4", and use the same artwork to cut 3/16 squares, then glue them into the other holes with the bottoms aligned.. You now have 1/6" drop..

[Rodne Gold]

Anither method is just cut the squares out of 1/16th pex , cut a border round it all and glue the lattice left onto the base. Clean , quick and neat.

[Matthew Sullivan]

what kind of glue or adhesive would you use for something like this, that will hold steady and not look bad or leave residue.

[Michael Kowalczyk]

Mathew,
How long does it take to laser that with :( results?
It may be a project for a CNC if the inside corners can be radiused. it would be much faster and definitely have a smooth bottom.
just a thought,

[Richard Rumancik]

Matthew
To glue acrylic without anything showing over a large area would be challenging. Perhaps you could apply find a UV activated adhesive. Maybe apply some spots of adhesive and hide these under some graphics.

But maybe you should back up a bit. Why does the customer want a clear gameboard? Are there no graphics on the board? If the customer is just doing a one-off for personal use then anything is fine and my comment is irrelevant. However, if this is intended to be a new product then maybe he/she should sit down and determine what is actually needed, how it would be made in production, etc. keeping in mind that the "standard" material for gameboards is cardboard. Which is very inexpensive to fabricate, bond, print, diecut, fold, etc. You could laser cut two layers of cardstock very easily and bond them.

On the other hand, maybe there is a good reason for clear acrylic . . . if it is really needed, then they would need an expensive injection molding tool for production.

[Mike Null]

Have you considered using post script fills which you can set as you like. You will have a pattern of your choice but still get the depth.

You'll find them on the fill tool flyout.

[Rodne Gold]

Any capiliary action glue will work real well for this application and wont leave marks , tensol 12 I think is what we use. DO not use Chloroform etc , use a proper acrylic glue. The fact that the surfaces are smooth makes life easier , the reason you see glue marks when joining pex is cos of the roughness of the cut/processed surfaces.
The only thing you would have to be careful of is trapped air bubbles , and thats not an issue with a lattice work and the other issue , also not that pertinent with a lattice is the fact that pex is incredibly static prone and you would have issues bonding one large surface to another cos of attracted dust etc on the surfaces that would mess with the bond and its optical properties.

[John Hardage]

You could always get 1/16 acrylic, cut all the way through, then put a 1/8 or 3/16 backup sheet if you have to meet 1/4" with acrylic adhesive. Nice, lasered holes, clear all the way through. Mind you, I haven't tried this, I'd imagine you would have to be careful with the adhesive to press tightly to avoid any bubbles. I was looking for a 1/16 source for myself, decided to look in earnest when I read your post:) www.delviesplastics.com/acrylic%20sheet.htm

[Matthew Sullivan]

Hello, I tried the engraving to the depth with a pattern and it turned out amazing :D. Worked really well, I also used the glue you said Rodne and glued the lattice work ontop and that turned out really well too :D So I'm going to give him a choice and pricing for each. I really appreicate the help people, nothing but help.

Thanks again

Matthew Sullivan

[Jim A. Walters]

When we first got our laser (prior to discovering SMC) I was trying to make a rack to do multiple dogtags on. I bought some 1/32" ADA from Johnson Plastics that had adhesive on the back. I cut 99 blanks from a 12x24 sheet, and tried to squarely stick it to a 3/16" piece of acrylic. It was a disaster. Once all the blanks were cut out, it was so flimsy, it was like trying to lie a hankee down straight and square on the first try.

I ended up rastering the blanks from a 1/4" sheet of acrylic. It warped like crazy. I drilled and tapped another 1/4" sheet and bolted the warped sheet to the new sheet to hold it flat. If I had to do it again, it would be completely different using a mix of all the great knowledge gained from this board!