SFM is how fast the cutter edges are moving around the axis of rotation of the cutter. The spindle of the mill is the axis of rotation of the cutting edges. You mentioned 20K rpm for a .0625 cutter. You have 327.25 SFM. The cutter moving through the material is the G93 (inverse time), G94 (FPM), G95 (IPM). I don't know how the control calculates (DPM) Degrees Per Minute or (DPR) Degrees Per Revolution. You don't want (CSS) Constant Surface Speed. You want (CFR) Constant Feed Rate to give you a (CCL) Constant Chip Load. For that you (or the control) would need to know the distance the cutter is from the axis of the rotary table. The TA (Tool Axis) statement in my CAM system allows me to tell it to calculate the feed rate at the tool tip or some distance along the tool axis if I want to have the feed rate calculated for some distance away from the tool tip. For example, if I have a 4 inch long cutter and want the feed rate calculated 2 inches (or some other value) above the tool tip. It can get complicated depending on the machine configuration.
regards Stuart On Wed, Sep 30, 2026 at 1:33 PM maurice e heskett <[email protected]> wrote: > On 9/30/26 13:42, Stuart Stevenson wrote: > > Surface Feed per Minute is only relevant on a turning process. On a > milling > > process the SFM is determined by the spindle speed. > How is this determined if B is turning 500 rpms while Y is moving 400mm > and the radii of the B is about 1"?, carving a bolt's 4x6 buttress > thread in hard maple at a 12mm pitch? One start while going down the > stick, 2nd start while coming back to the starting point? > > > > > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Addressee is the intended audience. If you are not the addressee then my consent is not given for you to read this email furthermore it is my wish you would close this without saving or reading, and cease and desist from saving or opening my private correspondence. Thank you for honoring my wish. _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
