Long End mills for cutting Acrylic

[crash5050]

I have a customer that wants me to cut some 3 inch thick acrylic, My bot has a 7 or 8 inch Z on it but I think I am going to need a longer end mill to go all the way through.

Is cutting acrylic any different than cutting any other substrate? I know speeds and feeds have to be right to stop the melting and so forth?? Any insight on where to get a 4 inch .25 or a .375 endmill?

David

[Brady Watson]

This is a pretty challenging job & I would go no smaller than a 1/2" shank on the cutter.

Before you commit to the job, price out 3" acrylic. After the hard swallow, decide if you really want to take the job on.

-B

[CNYDWW]

I was getting 2" optically clear cast acrylic 4x8 sheets for $2500 each. I could only imagine what 3" costs. It goes up and up the thicker you go too. 1 1/2" Thick was only $890 a sheet. Our source was Total Plastics.

Regards

[Xray]

If they are straight cuts, a table saw is the way to go - Not any blade will do, you need a triple chip design they run from $80 to $150, they cut smooth as silk.
If not straight cuts then, like advised, nothing less than .5 shank tool, this much work will dull them quick so you'll need a few, sharpness is essential. Less flutes the better, and high as feed speed low rpms as possible to reduce melting issues. A good sharp tool will not produce melting, once they start to dull it will melt in a hurry, might possibly snap first. Gets louder too, as the tool struggles to do the job, thats when you know its time to change bits and throw that one away.

[kerrazy]

There are 2 types of acrylic. Cast and extruded acrylic. This is an important piece of info needed. Cast is harder and usually crystal clear but surface is never completely flat. Ask me how I know. I v carved a large monument and after running job, looked to see some serifs got missed and some sunk real deep. Table was surfaced before job, second go round I broke job into grids and z-zeroed each grid individually.
Also Brady is bang on, if you go any smaller you will get serious deflection lines. I would cut multiple passes and then final .01 clean up pass fairly quickly while leaving just a skin of material holding it to table