Help with Feed and Speed

[sa6200]

Hello gangs,
Whenever I needed help or needing advises, you all have always been there for me. For that, I really appreciated. Now with that sucking-up out of the way, I need some help with my engravings.

I have been milling for years and haven’t had any problems to speak of except for the recent engravings. Enclosed please find my pics of my recent engravings. I just can’t duplicate the same type of clean-cut engravings as the sample pics.

Here are my parameters if this would be any help: I am using Tormach PCNC machine, so the maximum speed is 4500 rpm.

Engraving cutter: Mostly using 1/8” conical or I do have a 3/16” spring-load 60 degree conical

I have tried both higher speed of 4500 and as low as 450rpm and getting the same results.

No coolant. Dry mill

Letter sizes: less than 1/8”

Please note the materials in the example pics are stainless steel.

Any suggestion on a proper feed and speed for brass and silver? or proper method that I should be doing.

Advice will be greatly appreciated.

[jalessi]

Dry with such a small cutter and at low r.p.m?

I would be using a two flute and flood coolant unless you can run a very high speed "40,000 - 60,000 rpm" and then the D.O.C. would still be less than .003 max per pass.

Jeff...