[replicapro]

I want to cut acrylic sheet, and I was wondering if there is a special end mill for doing this so the edges of the plastic stay smooth and dont need to be polished after the cut.

[ger21]

Onsrud makes bits for plastics. http://www.onsrud.com/index.html
Vortex also has some. http://www.vortextool.com

If you want a polished edge, you'll probably have to polich it, but it is possible to get a very smooth edge. The above tooling is generally for routers, btw.

[BT1]

slot drill...

[Kmed]

WHat spindles speed / material thicknees / cutter diameter.

Machine ridgidity will have a marked effect of the surface appearance as well. You can see what you cant feel.

2 flute straight cutters 3/8 or 1/2" I have had excelent results at 15-20 k spindle speeds, air blast and 100-200 ipm feeds. So acrylics are harder or softer which will also affect the cut IE cast / extruded sheet.

To get a perfect edge a diamond cutter will works best, and a diamond edger will give you the best machined finish.

Hope that helps.

[E-Stop]

Depending on the application, I have used router bits and Dremel bits. The Dremel bits work well in a variety of materials and they are inexpensive.

[DareBee]

Most plastics manufactures recomend using router type cutters.

[gleas]

If you have the rpm's, (6000+) Onsrud up spiral router bits are very good for edge finish. Plastic generally requires much more rake on the cutter, and the router bits fill that gap.

-Greg

[neilw20]

I have found that conventional milling works better because the rubbing action burnishes the surface and helps to stop the cutter eating the chips.

Use plenty of air to keep the chips clear.

If there are many parts to do, cutter wear can become significant, so I use solid carbide.
The coated cutters will give a better finish but are much more expensive, and they appear to have a more finely ground finish.

[eaglezsoar]

Onsrud 63-515 1/8" O-flute. 13,000 RPM at 120 ipm feedrate with 0.06" depth per pass. Not inexpensive but one of the best for all plastics.

[SRT Mike]

I tried every Onsrud cutter they recommended and they worked like *crap*.

I followed their recommendations to a T, tried changing my cutting conditions and never got them to work worth a damn.

I do not cut very thin stuff, nor do I do routing (although I cut parts out of acrylic on my VMC).

In my experience, HSS seems to give a better finish than carbide. I was told HSS cutters hold a sharper edge. I have a piece of 1/2" acrylic block on my desk right now, I cut it out with a 1/2" eight flute finishing cutter (this one is carbide). The finish is not crystal clear, but it's damn close. It's a 1/2" thick block, 2" x 2" square. If I hold it up against my computer screen edge on (I cut out 4 sides), I can read text through it no problem - so it's pretty damn clear.

That was around 30ipm, full depth, 1/4" on the width, shoulder cut, 6000rpm with coolant. Coolant makes ALL the difference. I 3D profile acrylic all day long - without coolant it's hazy with coolant I get a very clear (almost crystalline) finish.

[ImanCarrot]

Acrylic? I cut lots of that with HSS two flute end mills- lets the chips get out. Air mist coolant- again to get the chips out.

One note: Cast acrylic machines much better than extruded. I won't machine anything acrylic unless it's cast.

You can smear the part with soap if you don't have air mist (thanks Geof)

Hope this helps.

[tcarita]

- wrong place -