Greetings everybody; This code, using g33 to cut a mildly tapered thread, I noted that my x axis increment, and my Z axis increment, were describing an approximately 45 degree path where the tool turns the corner. But it ran, and made a tapered nut I needed on TLM.
I had increased the per-pass DOC from .055mm's to .070mm's and thought I waste a nut to see how it looks. At about the time it was cutting a full depth thread, it broke the chip. Looking at the backplot pattern it occurred to me that my math foo was being funkity again. It made common sense that if the included angle of the thread was 60 degrees, Or a thread width of 0.866 of the tpi. But tats both sides of the cut, where I wanted the usual 29.5 degree, in this case applied so that the right, front side of the tooth is being shaved. Then I got the idea that the tool image would be a good comparison, the left side of the tool taking only a very thin shaving, essentially the same setting that pitch offset per pass as used in a G76 when its told to advance at 29.5 degrees. The resultant backplot, when comparing that turn the corner point with the side of the default tool when that image is moved to coincide results in a several degree missmatch, leaving a gap at the non-cutting side of the tool that gradually gets wider. This says my Z advancement per pass is too much. And the lack of braceing of the non-cutting side of the tool is generating a low frequency buzz to the cut, possibly indicating I do not yet have the spindle bearings snugged up to zero clearance, a buzz that might go away if I can get the advancement per pass at 29.5 degrees So, is that default tool image, un-rotated, supposed to be a 60 degree included angle at its top tip, image? Or is it worthless for use as an on-screen gage pattern? Thanks. 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> ------------------------------------------------------------------------------ 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
