Re: Feed and Speed calculator, what the HECK?

Hi Joe,

for a starting point, considder feeding the bit at 0.001" per
revolution.

your 7,000 RPM would advance 7 inches per minute.

there are a lot of factors to considder when cutting. strength of
tool bit is one, strength of part is another.

Since I hae been home machining and not using big lathes and
Bridgeports, the depth of cut is way down.

Again for starters, don't try to cut the full radius of your end mill
in a slot. if you need to get that first slot cut, cut the depth of
cut at less than 1/4 of the cutter diameter.

so, your 3/16 (0.1875") dia end mill would feed at 7 inches per
minute, and around 0.04" deep.

for a trial, feed at that depth and do a 1 inch pass at like, 1 IMP
for 1 inch then speed up to 2 ipm and so on. you should hear the
motor start loading. if you are watching amps on your cutter you
should also see them increase.


Just a starting point. you will find what is best for your machine.

Dave

--- In CAD_CAM_EDM_DRO@y..., "onecooltoolfool" <joevicar3@i...> wrote:
> I need a good way to calculate feeds and speeds for CNC milling.
> The chip load per tooth method in the machinery's handbook is total
> crap. Granted I haven't looked in the lastest edition, (24th ed.)
but
> by their calculations I would be putting a 3/16" endmill through
440
> stainless at 7000 rpm and 80 ipm. Right. It lasted about 2 seconds.
> Back to guessing.
> Where does the depth of cut come in?
> Coolant, no coolant?
> Lenth of the tool?
> There has to be a good FREE, tool out there to do this. Where?
> Joe V.