Inventables Community Forum

Cutting Letters

Hello all
I’m new to the CNC machine and I’m really ready to throw this machine out the window lol. I’ve been working with this machine for almost 3 weeks now and I feel like I’m not closer to achieving what I set out to do, then I was 3 weeks ago. Can someone (anyone) help me with cutting out letters. I have Genmitsu Pro 3018 with a 24v motor. I’ve tried “cutting on” “cutting outside” “cutting inside” and i’ve broken 4 of my CNC Router Bits, with no success!!! I’m cutting on a 2mm acrylic cast sheet, with 1.6, 1.8, 2.0, 2.2 and I’ve managed to break all of them. I’m so confused about setting the correct settings from “Depth Size” “Feed Speed” PLEASE HELP ME!!! I’ll take and appreciate any assistance from anyone…Thank you in advance!

I can only guess that your depth of cut is too deep and your Z feed rate is too fast for the material. Acrylic is pretty hard stuff. Try slowing the feed rate down and don’t go as deep. Perhaps try a larger diameter bit too. Putting a lower number in both Feed Rate and Plunge rate and Depth per pass would do that in Easel.
Change the numbers in cut settings.

@AzaliaLatimer I understand your frustration. I was there once. You might want to take a step and take a look at my videos. It is designed mainly for newbies. Https://youtube.com/c/pawpawsworkshop

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What are your feedrates, spindle speeds and depths of cut?
I’ve no idea what one of those little machines can handle, but you want to move faster and shallower if you’re having trouble. Acrylic is generally pretty easy to cut, but you need to feed fast.

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Do you use these bits? If so these are “burr bits” and totally unsuitable for plastics.

Acrylic will melt if the RPM is too high, feed rate too low or bit is not able carve “chips” - it will begin to melt and all bets are off. I think this is what you experience.

Yes that’s the exact set of bits that I have. So are saying that these bits are no good for cutting letters in acrylic?

Thank you and I have actually reviewed some of your videos. Do you have a specific one that would help me?

No good at all. Burr bits dont make chips so the acrylic heat, then melts and create havoc for the bit. Burr bits are for materials like FR4 glassfiber boards like PCB´s.

You need a single flute upcut bit.

Amana makes bits specifically for cutting plastics. I have had great success with them.

I’m new to CNC as well, Amazon has flat and ball tip single flute bits. Is one better than the other? All I have is the ones that came with my machine (3018 Pro) and the burr bit set like the OP.