Lets talk feed rates (milling)

[MBG]

Okay. I am trying to program haas mill. I am used to lathe feed rates of .015" inches per revolution.


How do the mills work?

[-Chris-]

Actually Surface feet per minute (SFM) mostly recommended by manuf. of cutter but you can get close with that little program on main page Downloads called SPEEDZ at least it will give you a look see at the process it goes through. It gives a range for SFM for matl type and you fill in cutter info and you fill in chip load and it gives you RPM and Feed in inchs per minute
Chris

[MBG]

Originally Posted by -Chris- Actually Surface feet per minute (SFM) mostly recommended by manuf. of cutter but you can get close with that little program on main page Downloads called SPEEDZ at least it will give you a look see at the process it goes through. It gives a range for SFM for matl type and you fill in cutter info and you fill in chip load and it gives you RPM and Feed in inchs per minute Chris

Oh yea that is right. SFM. I rember now.

Where is that program? Do you have a link?

[-Chris-]

Go to top of this page top left click home page, @ home page look at downloads at right hand side you should see Speedz there.

[crabbass]

you can program your mill anyway you prefer.
If you think in RPM simply convert by ((RPM * DIA) / 3.82= SFPM)
feed per minute is G98 to calculate use (RPM * ipr= ipm)
feed per revolution is G99 (setting 56) to calculate use ( ipm / RPM= ipr)
I'm not sure what the max feed/rev is on your mill.Be careful!!!! if you leave it in IPR (G99) and have even a small feed command from when you were using IPM (G98) feeds, it might get ugly.
Feed in IPR is actually pretty handy if you want to always maintain a constant chip load (even when you overide the spindle speed )

AC

[MBG]

I notice a lot of programmers choose to use IPM

Is this correct?

[MikeOD]

IPM and IPR are both "correct"...most people use IPM because it's traditional, and it's default.

IPR is nice though if say you've got a cut where the surface finish is very critical and exacting (maybe on a bore or something), and you know the chipload that will get you that Ra...you probably still have a range to work in for surface speed, so using IPR will allow you to play with the spindle speed override to get the cutter running the best.

[big_mak]

On my mill I always program tapping in IPR. It's safer if someone changes the RPM. You don't have to remember to change the feed.