I have had good luck using both the 1mm and .5mm diameter ball nose endmills from SpeTool. I am usually only engraving 50 to 100 thou. deep into 1/4” coloured acrylic. I started using the spade bit type but was breaking them almost as fast as Amazon could deliver them. I am using a 300 watt Genmitsu 3030 at 12k rpm Feed rate of 635 mm/min and doc 0.5 mm. Any melted swarf can be knocked of with a light fingers touch.
On some worry some carving I reduce feed rate to 25 in mm and a DOC of .02 in at 12k rpm.
Aluminum tags are usually done at a DOC of 0.13 mm and a feed of 1270 mm/min.
I get quite a few plates before the cutter gets dull. What do you use for settings and 1/8 or 1/4” cutters?
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Quite a few meaning hundreds not thousands
For acrylic try lowering the speed. I found a single flute or O-Flute bit and anywhere from 1000 to 8000 reduces friction which prevents melting and the single flute improves chip removal so less time for them to melt on the bit. I did a bunch of trial and error writing down my settings, run a test cut, evaluate, adjust settings and repeat until I get the quality of cut I’m looking for.
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Thank you for the response. I have not got a zero flute cutter yet but hope to soon. I am looking into making some acrylic 1/4" thick parts in the near future so I will probably be ordering a couple soon I think. 
Do you have ant comments about my first dice project build.
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Wondering why not increase spindle speed and leave the feed alone? I have a 12k 1 hp. spindle.
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I have used AI to help guide me a bit but it’s not always right so running test cuts helped me to dial in some of my settings. Recently I have come across something called chip load. Basically how well the chips can be removed and expelled. Divide the feed rate by (Spindle speed x number of flutes) for acrylic try to keep the chip load to 0.08 - 0.15. Larger bits have a larger flute and expel chips better than small detailed bit. I have bits down to 0.8mm. Best to cut large sections out with larger bits at a slightly smaller size (0.05mm per side) and finish off with smaller bits for fine details. you will also need air to blow away the chips as they produce. I ended up using a powerful hand held duster from amazon. Invest in one that comes with a spare battery that can be charging while your using the blower. I made the mistake of a unit with a single none replaceable battery and I have found myself without a blower and a cut that has not finished. If I’m just drilling a hole using a standard drill bit instead of a router bit I found slowing the spindle speed down to 300 to 400 RPM did a great job with no melting.
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Thanks for the settings. What is your spindle power?
I have just started using an old aquarium pump and the tip nozzle that came with my Genmitsu to blow the cutter swarf off of the bit. I am also using a handheld low power handheld vacuum to make for easier and quicker clean up well. Acrylic swarf seems to go every where.
After I get more time using the aquarium pump I’ll post if there are any noteworthy results.
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I’m using a Lunyee 3018 Pro Max that is rated at 500 Watts of power.
