I am cutting some gears with pretty fine teeth, and would prefer them to be made of acrylic.
When I cut them I am finding significant “stick”, where the acrylic seems to melt and then fuse back with itself, making extracting the parts challenging.
When I do get the parts out there are rough edges where these adhesions happened, which is making it tough for the gears to mesh smoothly.
I’m trying a few things to get it to work, but the one idea I haven’t tried yet is doing multiple passes. Has anyone tried this? Does it make sense to do two passes (one to cut and another lower power to clean the cut and fully separate the pieces)?
As it stands now I am doing full power as quickly as I can manage, as is typically best for most materials. I wonder is this is shooting myself in the foot, but I am concerned about doing multiple passes because acrylic’s thermal expansion is pretty noticeable. I am concerned that if I do a second pass the acrylic will have shifted just enough to ruin things.
Anyway, I thought I’d ask before I go too far down that path, might save me some effort if people here know it’s a dead end.
Are you using CAST acrylic? With or without masking?
I use 145 speed with full power to cut cast acrylic with masking, and it cuts perfectly with 1 pass.
I have never used extruded acrylic, but I heard is doesn’t cut very well. The acrylic I buy comes with masking on both sides.
edit: I have only cut 1/8" acrylic, so my settings are for that.
My “chonk” acrylic setting is 150 vrooms/100 pews x2.
My 1/8" Acrylic cut | Smexy setting is 118 vrooms/75 pews. I use this for puzzle cutting acrylic, and slow down to have a better cut, so that might work a little better for your gear teeth. Obviously different machines and whatnot, your mileage may vary, etc ad nauseum
I have some pretty intricate parts out from acrylic using default settings in the past, but I am having to bump the settings up (well, slow it down) now as I approach 5 years.
This is obviously wood, I know I took a pic of the one I cut from clear acrylic a few years back, but I guess I never renamed it to file in my design folders. That one was about 3" with a loop to use as a hanger from a car window for a Hindu friend. All the parts fell out when I lifted it from the bed. I gave her this one as a decoration.
I think part of my issue is one of tolerances. I’m trying to get perfect involute gears and they’re very fussy with this one generator. I made a new version with a different gear generator and it went much better, but even that binds here and there.
I’ve since switched to smooth rollers and I think I’m good to go now.
Involute teeth are not very strong in acrylic until you get to a pretty coarse tooth. I use a round profile for any acrylic gear that has to transfer load. They are much smoother and you don’t have to be as careful with the tolerances. They also won’t break unless you are really loading them since their root is really large.
I have never tried this for my gears, but I haven’t had issue with acrylic not being strong enough yet either. (Of course I use thick acrylic for weight bearing gears)
I don’t think I have ever broken a gear except when I dropped my clock from the wall. That broke a couple of teeth off the ratchet gear for the weight. But it still works, just less teeth to grab.
I tried annealing proofgrade and it didn’t seem to make a difference. I cut thin strips and had a few each controls and pieces I annealed, and could tell no difference.
I don’t remember what project I had in mine. May have just come up here and I like testing stuff.
I have wanted to play with Delrin, but I haven’t found a trustworthy source that was priced to the point that I was comfortable playing with it. That stuff is expensive, and hard to find in the size I could use.
Has anyone heard of rubbing a thin layer of liquid dish detergent? There is an acrylic company called trotec who had a video showing it worked well because of its flame retardant properties? Considering the source, it seemed to have validity but I haven’t been able to verify. The differences that showed up were substantial when cutting. I am new cutting acrylic and not sure how to find out if this can be used in a glowforge?
