My personal opinion is that all G0 moves should always be exact stop positioning moves not blended moves. To treat them as anything else seems silly. If the previous behavior of Linuxcnc was to blend them, then it is just plane wrong and should be corrected. Having multiple G0 moves executed after each other is somewhat of an unusual situation to start with. And is the reason I had never noticed that G0 moves were blended in the old planner. But neither planner blends a move between a G0 and G1 move as far as I know. Because of this most people never notice. I am pretty sure G0 moves are exact stop positioning moves in all the other CNC controls I have worked with (Fanuc, and others).
----- Original Message ----- From: "sam sokolik" <[email protected]> To: "Enhanced Machine Controller (EMC)" <[email protected]> Sent: Wednesday, March 29, 2017 11:22:10 AM Subject: Re: [Emc-users] Version 2.7 positioning problem during cnc operations The cheap and dirty way would be to add add in the TRAJ sectio/n ARC_BLEND_ENABLE = 0 /This puts the trajectoy planner into pre 2.7 mode (pre circular arc blend - 1 segment look ahead) You obviously lose x segment look ahead. During testing exact stop mode happened between G0 and contouring moves - but that changed the behavior of linuxcnc so I think it was taken out. (now it blends between all segments types.) Currently the fix is adding G64Px.xxx at the beginning of all programs. sam // On 3/29/2017 9:37 AM, Stuart Stevenson wrote: > Gentlemen, > This is connected to the G64 question I asked on the developers list > yesterday. > > G64 P0 does not change the positioning problem on the machine. > > Problem description: > desired machine motion > position XY with Z above the material/work level > move Z to material/work level > face mill top of material > > encountered machine motion > position XY with Z above the material/work level > result as expected > move Z to material/work level > result not as expected - as the tool approaches the final Z > position > the tool moves an amount > toward the final XY position > and cuts into the > material/stock > face mill top of material > result as expected > > The work around has been to add an intermediate point after the z move that > will cause the rounding to fall short of the material/stock > The BIG problem is the customer has many proven/certified programs making > parts on this machine. The quality manual requires a full first article > inspection procedure to be performed on the resultant machined part after > ANY change in the process. This is not acceptable to the customer. > Customer wants the machine to just perform like it did with the previous > (old) linuxcnc version. > Customer is asking for revision to old version if fix is not able to be > accomplished rather quickly. > > thanks > Stuart > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
