As I hand code and can therefore control direction the rotaries move I can cut against the play/backlash inherent in the cheap rotaries I use, often the B axis will be locked though for greater rigidity. Im mostly cutting light weight brass blanks though.
A reason I hand code is I cannot afford CAM software to do the type of work I do. here the benefits of Ocode subroutines come into their own. So for a helical Im using XZ for the cut Y to cut deeper A for the helix rotation along the blank and B to set angle to get the cutter in line with the groove. so the gcode has a number of constants to set before use eg #<teeth>=160 #<depth>=[.100] (cut depth adjust as needed) #<blank_thickness>=.25 #<helixangle>=81 then after some preamble and calculations of settings for a particular gear eg #<drop_track_center_z>=[[sin[90-#<helixangle>]]*#<blank_thickness>] then the subroutine O100 sub (subroutine to cut N teeth) #<cnt>=0 O101 while [#<cnt> lt #3] G1 f4 X0 Y#2 (move to cut start) G91 (set relative) G1 F4 x[0-#4] a[0-#5] z#6 (M30) (stop to test if tool hits rotary table) G0 y[0-#2] G1 F50 x[#4] a#5 z[0-#6] (actual cut) ( G91 )(set relative) G0 A#1 (rotate blank) G90 (set incremental) #<cnt>=[#<cnt>+1] O101 endwhile O100 endsub then the lines (B can be locked after this next line) G1 f60 b[0-#<helixangle>] (set helix 90 deg to cutter rotation) O100 call [#<angle>] [0-#<depth>] [#<teeth>] [0-#<drop_track_center_x>] [#<rotateangle>] [0-[#<drop_track_center_z>]] I leave commented lines in 1) to uncomment to stop the code at certain points while setting up and 2) to remember what I did I also use sensible names for the variables I hope. The touch off to get the cutter on the centreline in my case is a pain. Dave Caroline On Tue, May 3, 2011 at 8:29 PM, Steve <st...@tgifinc.com> wrote: > Hi Dave: > > So when are "special kinematics" needed? When are they not? Are you > rotating your gear blank about A&B to establish the desired cutting plane, > locking it in that position, and then cutting with XYZ? > > Steve Van Der Loo > > Message: 3 > Date: Tue, 3 May 2011 06:36:04 +0100 > From: Dave Caroline <dave.thearchiv...@gmail.com> > > For certain classes of work you dont need special kinematics, I have > been cutting gears for clocks > on a mill with stacked A on B, I hand craft the gcode though, as it > happens to suit the work I do. > > Dave Caroline > > > > > ------------------------------------------------------------------------------ > WhatsUp Gold - Download Free Network Management Software > The most intuitive, comprehensive, and cost-effective network > management toolset available today. Delivers lowest initial > acquisition cost and overall TCO of any competing solution. > http://p.sf.net/sfu/whatsupgold-sd > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ WhatsUp Gold - Download Free Network Management Software The most intuitive, comprehensive, and cost-effective network management toolset available today. Delivers lowest initial acquisition cost and overall TCO of any competing solution. http://p.sf.net/sfu/whatsupgold-sd _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
