On Thursday 18 January 2018 10:41:50 Kirk Wallace wrote: > On 01/17/2018 11:45 AM, [email protected] wrote: > >> On Jan 17, 2018, at 10:43 AM, Kirk Wallace > >> <[email protected]> wrote: > >> > >> I did a rewrite a while back: > >>> http://wallacecompany.com/tmp/G76/G76-7b.cc > >>> <http://wallacecompany.com/tmp/G76/G76-7b.cc> Interesting Kirk.
However it generates a couple of questions, first of which is that this looks as if it could be duplicated in a gcode file with the use of named subroutines. Given the speed of available machinery, would it make any diff in execution time? Second, this seems workable only for std 60 degree sidewall threads, so it would have to grow a knowledge of acme threads in order to solve Tom E's problem. Tom, can you give the math that describes your single point tools geometry? I think the side angles,(s/b 15 degrees for /most/ acme's) the width of the point those angles pivot on (here I'd assume the previously quoted .125") which implies the actual width of your tool, at the 50% of cut depth point is then .0630", the extra half a thou being just enough backlash to allow a .0625" width tooth to turn easy if well lubed. So the angles could pivot at that width point, then what is the actual depth, from which the width of the tools flat tip could be determined? I'd assume (that word is scary, actual practice has made a fool of me before) that the tools tooth is actually a few thou longer so that the tool's shank would clear the top of the already cut tooth as its making the final and spring passes. Thoughts everybody? > >>> http://wallacecompany.com/tmp/G76/Screenshot-g76_kw-1a.png > >>> <http://wallacecompany.com/tmp/G76/Screenshot-g76_kw-1a.png> > >> > >> This might not be fully debugged. > >> > >> This still has a retract hazard with some end taper settings: > >>> http://wallacecompany.com/t_tmp/G76_doc/g76_tool_clear.png > >>> <http://wallacecompany.com/t_tmp/G76_doc/g76_tool_clear.png> > >> > >> The original drive line shifts with each pass. The direction of I > >> doesn't match the documentation. This should affect diam/radius > >> rather than behave like mill space. > > > > This is interesting. In your re-write, is the drive line set by the > > X position before the first move, or is it related to the I > > parameter (and how)? I would like to test this, what is the best > > way to install it? -Tom > > Both the original and my version uses the current entry position as > the base position. This saves having to have the entry position as > part of the command. The original has a fixed pattern that shifts with > each pass. Mine has a fixed drive line and alters the rest of the > pattern. 'I' sets two features, the tool clearance from the stock, and > the type of thread -- external or internal. 'I' is applied to the base > position and tends to be the last parameter to be calculated after the > rest of the requirements are met. 'I' works for front tool post lathes > but these days tool posts can commonly be on both sides. A problem > with my version is that it breaks old g-code, so this would need to be > addressed. The original G76 was/is a great addition to LinuxCNC but I > believe it needs refinement. Cheers, Gene Heskett The above content, added by Maurice E. Heskett, is Copyright 2018 by Maurice E. 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> ------------------------------------------------------------------------------ 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
