acrylic speeds at 30000rpm

[atrueresistance]

I was wondering what speeds I should be running. The wiki states

Code: Select all

Bit: double flute 1/8" end mill
Feed: 400mm/min
Speed:20,000 RPM
Cut Depth: 0.08"
Stepover: n/a (through cut)
Plunge Rate: 75mm/min.

So translated that would be.

Code: Select all

Bit: double flute 1/8" end mill
Feed: 15 in /min
Speed:20,000 RPM
Cut Depth: 0.08"
Stepover: n/a (through cut)
Plunge Rate: 2.95 in/min.

I don't have a way to limit my dw660 speed, so this needs to be recalculated for 30,000 RPM. I looked for an online calculator, http://zero-divide.net/index.php?page=fswizard, but this states I should run 12,718 RPM. . . Has anyone had luck at 30,000 rpm?

So far I've tried the translated speeds, but with a depth increment of 0.015". The result was melted plastic stuck to the bit, to the point where I'll have to melt the plastic to remove it.

I also tried a cut feedrate of 60 in/min with depth increment of 0.015" which resulted with less buildup. The only buildup was stuck to the plastic and not the bit, but not a clean cut. This was cut short when path varied from previous path cuts causing the machine unneeded stress.

[PsyKo]

If you can't reduce the RPM, try lower flute end mill. Single flute will already reduce the heat caused by the high RPM.
A single flute at 30k RPM is equivalent to a double flute at 15k RPM...

[Estlcam]

Hi,

if you have no way to reduce rpm or increase feed as required try cutting with lots of water and a little dish soap to keep the router bit cool.

Christian

[atrueresistance]

I was spraying wd-40 when using the faster run. I ordered a MLCS 9400 speed controller that was discussed in an earlier forum thread, and can provide feedback once it arrives.

If you can't reduce the RPM, try lower flute end mill. Single flute will already reduce the heat caused by the high RPM.
A single flute at 30k RPM is equivalent to a double flute at 15k RPM...

I'm not aware of any single flute end mills. The wiki does not have any information on a single flute. http://www.shapeoko.com/wiki/index.php/End_mills

I've only found from my research online these types:

• 2-Flute - Allows maximum space for chip ejection. Used for general milling operations.

• 3-Flute - Excellent for slotting. Used for general milling operations.

• 4, 5, 6, and 8 Flute - A greater number of flutes reduces chip load and can improve surface finish, if feed rate remains the same.

• Quoted from http://www.endmill.com/pages/training/types.html

[Gadgetman!]

Well, there's a 5pack...

http://www.ebay.com/itm/5pcs-3-175mm-1- ... 564a04cd05

And these, from the sme seller is a bit more expensive, but mentions Acrylic in the title:
http://www.ebay.com/itm/5pcs-3-175mm-1- ... 564bc118ed

And...

There was my order off...

Yeah, I know it's Chinese manufacture, but at that price I'm willing to take a risk.

EDIT:
And our favorite eBayer, Drillman1, also has some neat stuf:
http://www.ebay.com/itm/5-1-00mm-0394-s ... 232d29d9d7
That's 1mm diameter, so you can make pretty narrow cuts.
Limited quantity, so...

[Improbable Construct]

I cut acrylic at 30000 rpm all the time.
On my machine (which is not at all stock or even close to it anymore),
I can cut through 3/8 acrylic single pass with a 2 flute end mill at 800 mm/min and have nice clean edges.
Your results may vary. The best thing is to get a piece of scrap and try it out.

[calica]

What diameter endmill?

[Improbable Construct]

What diameter endmill?

If you were asking me, I mostly use 1/8" endmills, unless I am cutting a large pocket.