Quick ? about .090 acrylic

[dubliner]

I have to cut .090, it came with paper on two sides. I'm thinking leave one layer on for vac hold down, but should I remove the top layer facing the spindle? Any bit, speed & feed advice welcome too - TIA Dubliner

[ken_rychlik]

Neville, I am running some .125 acry today. I am on the last sheet.

leave the paper on both sides.

Use bits made for acry. It's a major difference.

When you run to fast of move speed it leaves a rough edge.
When you run to slow it melts back together.

Start with about 2 ips and around 18k on your rpm.

When you run to slow on the rpm you can hear the material chatter. Chatter means a rough cut.

I sent you my phone number yesterday if you want to call.

Kenneth

[gabepari]

With a proper "O" flute with 2 cutting edges I start at 15k rpm and 4ips.

For anything less than 3/16" I use straight flutes, 1/4" and up I use up spirals.

Gabe

[toych]

I'm using Onsrud O flutes, 1/8 and 3/16 straight fluted bits. The speeds vary slightly but are roughly 18k on the spindle and 1.5-2 ips feed. This is on extruded. For a slightly smoother finish if needed I will run a roughing pass with a .015" offset then a finishing pass with the same spindle speed.

This works for me and the material I am cutting, each brand cuts a little differently and may need some tweaking on speeds and feeds.

Gabe, do you get a better finish with the spiral bits? I have a couple of Belin and Onsrud up spirals but need to increase my vacuum hold down before I can trust using them.

[robredick]

Hey there my funny talking friend. Is that job for SMSC? Next time you need to cut acrylic, you can come up and cut it on the Epilog. Light bulbs are fun.

[woodworx]

I use this method.


Surface the table
Use 1/8" onsrud super o up sprial
Cut to the depth of .085, in 1 pass or 2. leaving the paper on the bottom side
If done in 2 passes. Use an offset allowance of -.01 on your final pass to cut all the way through.

If you have a lot of cutouts, not cutting through the bottom paper will ensure your vac will not loose suction. On your final pass when you cut through, there will be almost 0 torque on your final piece, and deflection will be at a minimum. Hope this helps you. Good luck.