Milling steel tips

[jonathanw]

About 99% of the work I do is with aluminum, however I will be cutting a couple of parts in steel and would like to hear some tips or your general rule of thumb on DOC, IPM, and RPM for roughing / finishing. I will be cutting these parts on a CNC mill with carbide end mills.

[christinandavid]

Obviously a lot will be determined by the nature of the job and the rigidity of your machine setup, but you will probably want to halve your aly speeds and feeds and see how it goes. Milling strategy will most likely be similar if its just mild steel and you are not too fussy with your tolerances...

DP

[jonathanw]

I have been cutting a couple of parts out of A36 but the major issues I am running into is galling and breaking the endmills. So far it seems that if I take a very heavy cut with low feedrate and high spindle speed the tool will last longer. But most of the issues seem to be happening while pocketing. I have been swapping between carbide, HSS, 2, 3, and 4 flute tools and they are all galling. Best result so far has been with a 3/4 2 flute carbide cutter. Any input would be great.

[jamesu229]

3/4 four flute endmill, 1700 rpm 27 ipm no coolant. These are the parameters for most variable helix endmills. depth according to machine power.

[Farmers Machine]

A 36 is just scrap iron, and is somewhat gummy, if you have an air jet to blast the chips out of the pocket it will help. you can not recut steel chips or they will gall up on you. some time I apply a shot of cutting oil in the pocket to help keep the chips from sticking, my best results have been with Kool Tool oil. Bass tool company Houston Texas. are your carbide end mills coated? if not use about 200 sf coated with Tialn you can go about 750 sf feed about .0015 to 0.003 per tooth.
Good Luck
The Farmer