Acrylic edge smoothness?

Hi Guys,

been testing some acrylic cut outs with the 1/8 Solid Carbide Single Flute Upcut End Mill from the kit.

the cut is very accurate however I am left with the funny fuzzy edges.

Is it worth doing a finishing pass to smooth it out? is there tricks or tips here to get a smooth as possible edge as possible.


@Zach_Kaplan any ideas with carvey on this?

best regards

Here is my procedure. There may be better ones ,but this works for me .

  1. sand edge with 320 wet sandpaper
    - I use a 1/4 porter cable slander
  2. polish edge with cloth buffing wheel attached to bench grinder. I add a bit of polishing compound to the wheel ( harbor freight item #96780) .
  3. wash off excess compound in dish soap and water.

You can go straight to step 2 if you don’t have to remove rough saw marks. I highly recommend to practice on scrap to get your technique down.

I played with the flame polish, but didn’t hve a lot of luck .I may try it again to see if I can improve the process .

Good luck!

I asked a shop that machines acrylic professionally and they said flame polishing is the best approach. You can probably do a finishing pass to get it a little better but flame polishing will give it that glassy look you are probably going for.

thanks everyone for the replies. I will give the methods suggest a go but the problem is getting the acrylic smooth in the smaller pockets.

I spray painted the panel without any sanding to demonstrate. I am trying to achieve the same finish you can see on the top on the edges without too much work.

Here’s a video of the difference flame polishing can create:

I’ll email this question to our bit manufacturer too.

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He said a 3-flute finishing tool in an upcut. It will leave the best finish.

In smaller areas, such as pockets slow the feed rate and RPM’s (but don’t dwell) to get the best finish.

thanks Zach, I will give this a try as I was hoping to cut acrylic a lot!

I will update this space when I get my new bits in and trial them

I’ve been doing my own experiments as well with acrylic. I’m finding that especially on thinner pieces (~1/8" and thinner) there can be a lot of chatter especially near the middle of the material. The reason is because the material is flexing. Last night in addition to the clamps I added double sided tape. This dramatically reduced the chatter and made the edges much smoother.

You might also run a “finishing pass”. I ran mine at .020" depth per pass for almost all of it and then did a finishing pass that took of .001 the entire length of the bit. It made it much cleaner but only after using the tape because the material wasn’t vibrating.

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Hi Zach,

I will definetley give this a retry soon on some 3mm acrylic sheets with some newly ordered bits.

How is the carvey with double sided tape.

will the tape not rip or stick to the mdf causing it to be unlevel for future cuts?

I had success with double sided tape and clamps. Also I noticed that even with the double sided tape it performs better closer to the clamps indicating there was probably still some vibration near the center of the material.

I also had more success with the 1/16" bit than the 1/8" bit. I assume that is because it is removing less material.

None of the tape got stuck to the mdf.

Hi Zach,

are you you able to upload a photo of your results?

just for comparison. My new bits arrived today as well as a .125 in aluminium sheet 12" x 8" (from inventables
) that I want to drill holes to to match the MDF so I can make it a flat surface and use for the double sided tape.

I am planning on use hex socket screws to create a smooth surface so I can put other material on top of the alu sheet.

Hi Philip

I think a better option than aluminum would be to plane a piece of ABS or HDPE and then also make the hole pattern so you could screw if down.

That will give you a better place to work from.

Also aluminum requires specific bits to carve well.

Which machine are you working on?

Carvey primarily

I did another test last night where I put double sided tape on the bottom of the entire piece of 8"x12" acrylic. It came out smoother but still had marks. I think the nature of carving with a bit you are going to have some marks. Doing a finishing bas with the 3 flute bit will help but you’re not going to get it to be clear or shiny. However this morning someone sent me this video:

Check this out

Have you or anyone at Inventables tried carving a thin Acrylic sheet on a vacuum table?

One time with a prototype setup.

Have you tried it?

Nope, but it’s on my to-do list.