I’ve found most of this by searching the forum, but I’m double-checking to make sure I got it all right:
I’ve got parts I need out of thin, colorless, clear acrylic. 1/16" or 1/32" would be ideal, preferably the 1/32". Do you cut 1/32" acrylic? Or should I design to 1/16"? (I’m fine going with 1/16".)
I saw somewhere else that the acrylic sheets are actually metric in size, and that a 10% variation within a given sheet is to be expected. So I guess a better question to ask than the one above is if I should design to 1.5mm and expect a +/- 0.075mm tolerance on thickness?
For thin acrylic you mentioned the laser kerf is 0.005" to 0.010". Will it tend to be on the thinner side for 1/16" or 1/32" acrylic? The tolerances on these parts aren’t insanely tight, but I’d like to tab/slot the parts if possible, so the more information the merrier. Also, I saw that the laser’s centerline falls on the lines we put in our DXF files, so the kerf is more or less evenly split on both sides of the line. Is this correct?
With kerf allowances and material thickness variations, I was planning to make my slots .066" wide for 1.5mm material. Did I do this math right?
Finally, I was planning to assemble these with cyanoacrylate. I don’t forsee a problem there, but if you have any horror stories with this thickness of material and CA glue, let me know.
Thanks a bunch!
Yes, we can cut 1/32" and 1/16" acrylic. The closest thing we stock is 1.5-mm acrylic. You can probably get 1/16" acrylic from mcmaster.com, but please discuss special-order material with someone in our laser cutting department before you order anything. I believe 1/32" acrylic is difficult to find.
Whatever thickness you select, plastic sheet thickness can vary by up to 10% of the nominal thickness, even within the same sheet. So, 1.5-mm acrylic sheets can be expected to be anywhere between 1.35 mm to 1.65 mm thick (+ or - 0.15 mm, not 0.075 mm as you said).
You are correct that the laser kerf is usually 0.005" to 0.010" for thin acrylics, but we can’t specify anything beyond that range (whether it is closer to the small side might depend on things like the lens and mirror positioning). You are correct that the kerf is more or less evenly split on both sides of the line drawn in your file. You might want to look at the illustration of kerf at https://www.pololu.com/docs/0J24/4; that page is a good one to read before you get started with designing.
Drawing your slots with a 0.066" width (or even 0.065" width) should be fine, since with the kerf the slots would end up being slightly wider and you can count on the material to be at most 1.65 mm thick (~0.065").
Whatever adhesive you end up using for assembling your acrylic parts, you should use one that is specifically made for bonding acrylic, since using the wrong adhesive can cause problems such as crazing (formation of tiny cracks in the acrylic). We have heard that Weld-On #3 and Weld-On #16 work well.
I hope that helps!
It helps a ton. Thanks!
Yeah, I wasn’t sure if that 10% was a +/- 10% or a 10% peak-to-valley. Thanks for the clarification. I don’t think I need to special order any material for this. 1.5mm should work just fine. I put together a DXF for the first round of parts and sent it in for a quote. I hope to have all the drawings put together for the other parts by the middle of next week.