On Tuesday 06 September 2016 12:06:37 Kirk Wallace wrote: > On 09/06/2016 07:24 AM, Gene Heskett wrote: > ... snip > > > Thats no doubt true, but I've just found that the tapered thread I > > need CAN be done with the G76 we have. Its not even an error if E > > is as long as the drive line - tp_mm. If that value is exceeded, > > that should be an error but in 100% of the cases where the drive > > line starts off the end of the workpiece, it is of zero consequence > > because what it does is move to the I position, and next extends the > > overshoot distance to the right, cutting air, then it runs a taper > > the full length of the thread, air included. > > I checked the source for 2.7 and sure enough E is only checked for > being > > negative: > > double taper_dist = block->e_flag? block->e_number: 0.0; > > if(taper_dist < 0.0) taper_dist = 0.0; > > so any E equal to 0 or greater is okidoki. > > > Angle of the taper is UNK, but for my purposes, may even be slightly > > more than what I was playing with before. > > Try to make E equal to the length of the Z move. > That makes it back up z by 1 p after arriving at cutting depth.
So one must, to get the snapshots I just posted, use an e=thread-length - p. So I would assume that E is what you would use below? > rise / Run = tan(theta) so theta = arctan(rise / Run) > > rise = K, Run = E so theta = arctan(K/E) > > (BTW, NPT pipe threads are specified as a slope which is 3/4" diameter > in 1 foot length, or 1:16, so making E 16 times greater than K should > work for NPT.) > I've read that several times, but did not have it committed to wet ram. Thank you for the reminder. > The end taper path is designed to leave the thread at the end of the > taper, so figure out where your final threading pass should be. This > pass should be K deep into the material, but since this will have the > pass leave the material and the end of the pass, add a K's worth to I > to drive it deeper, then add your tool clearance to I. Sounds workable. Thats what 'wrappers' are for, right? > The Z length > only needs to be as long as the thread and enough lead-in to stabilize > the synchronized motion before you start cutting chips. Then lastly, > set your start position by calculating back from the final pass > numbers. > > > So please do not take away the E of G76. > > > > Any chance you could put a - sign in front of an S number to select > > the spindle, so -s6 s1000 m3 would spin spindle 6 at 1000 revs? > > E is needed for end tapers. Andy and I are arm wrestling over D which > is the only letter left for adding features to G76. > > I think there are also dot forms of G76, such as G76.1 available for > other features. G76.1 is an unknown G-Code according to the latest 2.7.x sim. So it is not available to be. And I just tested the 2.8-pre but I can't, no way to home it when the driver box is powered down. So until I can do it from its console, the is it in 2.8.pre remains undetermined. Thank you, Kirk Wallace. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
