settings for brass?

[aquanub]

hey all!

I know everyone hates these threads asking for speeds and feeds, but after using the calculator and more than halfing what it recommended I still destroyed 3 new 2F 1/16" endmills doing a contour cut on 1mm thick brass.

The calculator recommended around a DOC of .012 at a feedrate of ~20ipm. I had to dial it down to 0.006 and a feed of around ~7ipm.

What gives? I had an air blast and was using a vaccuum to ensure there was no chip welding. I felt 0.006 DOC should have been a walk in the park for PR... am I mistaken?

Would love some expert input!

Thanks (:

[peterd]

I destroyed a bunch of bits trying to engrave navy brass. Would like to know settings if you figured this out.

Best,

Peter

[Jerry]

Brass is hard metal. The machine ridgidity might be the issue here. There are ways to make the machine more ridgid.
The settings might not be the problem. A very large course mill with big flutes can grab the material. Big loud low freq. vibrations. An end mill with tiny flutes will erode away and not be as grabby.
But if the spindle is jumping around sideways, and you have a tiny end mill, it can snap the end mill.

I have made my carve king more ridgid by adding braces.

shallow depth cuts are probably best.

If you hold the motor and try to flex it, you can tell where it flexes. Dont cut your finger on an endmill doing this. Mine pulled in the y axis the most.

A ridgid machine can cut a lot of real hard material and fast. A flexy machine gets there with light cuts which takes much longer.





I show some mods here :  millrightcnc.proboards.com/thread/825/carve-king-mod?page=1&scrollTo=7434

double click pictures to resize them.

Hope it helps 

[Jerry]

2nd hand cabnets for Carve King


millrightcnc.proboards.com/attachment/download/1644



anyway check if your v wheels are too loose, stiffen the machine if you want, smaller flutes but not too small on the end mill diameter, make shallower cuts.

Single flute end mills work really well on these high rpm routers.

The Carve King is a great value as delivered or with mods. I have made cool parts and molds.


Hope it helps someone...

[Jerry]

Also the machine should be stiffer working near a corner and not in the center of the work area. 

[Jerry]

Try a larger diameter end mill, single flute, very shallow depth cuts.

if you dont want to stiffen the milling machine.

The end mill should not break off this way.