Acrylic Milling / Routing

[tulsaturbo]

I'm tired of melting this stuff so if there are any gurus out thare that can lend a hand by answering the following question - it would be greatly appreciated!

What is the proper router speed and feed for milling / routing acrylic?

[wcarrothers1]

Faster helps. I've done >80-100ipm

Perhaps lighter cuts..

Having a VFD spindle helps in that they do not tend to "heat" the bit as regular routers shafts and bearings tend to run much hotter.

Also perhaps try single O flute bits (like onstrud's) Beckwith Decor Products might be a good place to start for that. They are where I typically buy those bits. Also been playing with some harvey tool bits which are also nice..

I really never had good luck milling acrilic untill I ditched my regular router for a VFD spindle.

b.

[ger21]

I used this bit, 10,000rpm and 80-100ipm, with no melting at all. Should be no problem cutting even faster at the same rpm.

cnctoybox

In the Super-PID thread is a case I made from solid acrylic.

[tulsaturbo]

Originally Posted by ger21 I used this bit, 10,000rpm and 80-100ipm, with no melting at all. Should be no problem cutting even faster at the same rpm. cnctoybox In the Super-PID thread is a case I made from solid acrylic.

I saw your case on that thread and it looks fantastic!

I just got my Super-PID hooked up today. I made an air deflector which also holds the PID speed sensor for the router. I can live with the cuts on the acrylic that I made today since it will not be seen once mounted in position on the router but I have to cut some more acrylic tomorrow and wasn't sure where to start as far as rpm and feedrate now that the PID is working.

Is there a formula to go by regarding depth of cut per pass according to the diameter of the bit?

[ger21]

For 1/8" and less, I'd use the same depth as the diameter. As the diameter gets bigger, the bits get stronger, and you can cut deeper. But acrylic is hard, and shallower cuts might work better. What's important is that the chips don't get packed in the cut. If they do, they'll melt. In that respect, shallower cuts can be better.

But the bit type makes the biggest difference. I've cut a lot of acrylic over the years, and never used an O flute bit before. The difference is astounding.

[tulsaturbo]

Thanks for that info! I guess I'll be ordering some new bits...

[Drools]

Have a look at the eBay store "Carbide World"
Find their router bits for Plastic, I use their 1/8 shank bits on the hard acrylic type plastic found in LCD monitors, they work great and you do not need a high speed spindle. They are similar to Unsrud O-Flute bits for 1/4 of the cost.

[RomanLini]

I prefer HSS tools for acrylic, they seem much sharper than carbide. I've got 1,2 and 4 flute tools that all work well although obviously I run the 4 flute at lower RPMs than 1 or 2 flute tools.

Most of the time I run a 3mm 4flute HSS endmill normally sold for metalwork, it gives great finish in acrylic and I can buy these tools from the local shop so they are a good replacable workhorse. But the 4 flute won't clear material as fast so it needs a slower feedrate. With 3mm tool I use about 9000 to 11000 RPM and 30 to 50 IPM, but fairly light cuts of 1.5mm or 1mm depth. Like I said it's not fast but the wall finish is close to clear.

[tulsaturbo]

Originally Posted by RomanLini I prefer HSS tools for acrylic, they seem much sharper than carbide. I've got 1,2 and 4 flute tools that all work well although obviously I run the 4 flute at lower RPMs than 1 or 2 flute tools. Most of the time I run a 3mm 4flute HSS endmill normally sold for metalwork, it gives great finish in acrylic and I can buy these tools from the local shop so they are a good replacable workhorse. But the 4 flute won't clear material as fast so it needs a slower feedrate. With 3mm tool I use about 9000 to 11000 RPM and 30 to 50 IPM, but fairly light cuts of 1.5mm or 1mm depth. Like I said it's not fast but the wall finish is close to clear.

Thanks! I'll take all the info I can get...

I finally got the S-PID enclosed today in a 6" x 8" plastic project box from Radio Shack and is now ready to be mounted on the gantry

[RomanLini]

That's a nice big window on the box, I'm sure you'll be able to see the display.

What's the yellow thing, is that a mains plug/socket?

[tulsaturbo]

Originally Posted by RomanLini That's a nice big window on the box, I'm sure you'll be able to see the display.

Oh yeah, for sure...

What's the yellow thing, is that a mains plug/socket?

Its the output mains socket. I was going to order a plugin socket for an enclosure but I didn't feel like waiting again for another part to come in the mail...
Then I ran into this yellow socket while in the hardware store and saw how easily I could modify it to work so I went with it and this is what I got.

Maybe down the road I will make a better enclosure for the S-PID but this one will get me up and running for now.
Anything that I can get done now is a (+) for me since today is my last day of vacation before heading back to the daily grind...