I ran lathe for 5 years in the early 80s. 5T control. I used multiple cutter offsets all the time. When you are turning precision parts the cutting forces vary enough from smaller/larger diameters it is necessary to compensate each diameter separately. Or change the program which is not convenient.
On Feb 17, 2017 10:02 PM, "Todd Zuercher" <[email protected]> wrote: > What i need to do is set up a commanded tool path equivalent to the G41 > path, and see how that behaves with G64. I am suspecting that it may > actually look the same. I suspect that for the G64 path to "touch" the > small arc created by G41 The blending ends up just following that path > precisely. > > ----- Original Message ----- > From: "Kurt Jacobson" <[email protected]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Sent: Friday, February 17, 2017 6:20:05 PM > Subject: Re: [Emc-users] G41-42 and G64 Bug?q > > Craig, > > The D word is optional with G41/G42 and is equal to the tool number for > which the path is to be compensated. If a D value is not given explicitly > the value for the currently loaded tool it used. I can't think if an > instance when you would want to compensate for a tool that was not in the > spindle, and it seems like specifying the wrong D would be an easy way to > trash a part! My guess would be that the D word is rarely used with > G41/G42. > > You might be thinking of G41.1/G42. for which a D value is required, though > in this case the D value is the actual cutter diameter instead the tool > number. I believe Todd is only using G41/G42, so the D value is indeed not > needed. > > In the code Todd posted the compensation lead in was greater than the > radius of the tool, so no problem there either. > > I don't think this is a bug, I think we may just not quite understand the > way cutter comp combined with an abnormally high value of Q behaves. > > I am still mystified as to why blending seems to be disabled with G41/G42 > though. I need to so some more experimenting but I took the mill apart > again, so that will have to wait! > > Thanks, > Kurt > > *Kurt Jacobson, CMfgT* > Mechanical / Manufacturing Engineer > Center for Nuclear Studies | Southern Polytechnic College of Engineering > Kennesaw State University | Marietta Campus > E-mail: [email protected] > > > On Fri, Feb 17, 2017 at 5:42 PM, Craig Hodne <[email protected]> wrote: > > > The G41 and G42 require the use of the D-word. The D word refers to the > > line in the tool table where the diameter of the tool is to be read. It > > is often the same line as the tool number, but it doesn't have to be. > > The second qualifier is the travel of the tool from invoking the G41 or > > G42 must be greater than the radius of the tool. > > > > Craig > > > > > > On 02/17/2017 12:44 PM, [email protected] wrote: > > > Subject: > > > Re: [Emc-users] G41-42 and G64 Bug?q > > > From: > > > "Todd Zuercher" <[email protected]> > > > Date: > > > 02/17/2017 10:38 AM > > > > > > To: > > > "Enhanced Machine Controller (EMC)" <[email protected]> > > > > > > > > > Another odd bug like behavior I am seeing. > > > Set up a tool in the tool table with an extremely small diameter, load > > that tool, and run the g-code below with the optional block skip on and > > then again with it off. > > > > > > G64 > > > G43 > > > G0 X1.5 Y.375 Z1 > > > /G41 > > > G1X1Y.5Z.5 > > > G1X0.5 > > > G2 X4.5 I2 J0 > > > G1 X0.75 > > > G0Z1 > > > G40 > > > > > > Notice how having G41 turned on seems to shut off blending. Why is > that? > > > > > > ----- Original Message ----- > > > From: "Todd Zuercher"<[email protected]> > > > To: "Enhanced Machine Controller (EMC)"<emc-users@lists. > sourceforge.net> > > > Sent: Friday, February 17, 2017 11:25:06 AM > > > Subject: Re: [Emc-users] G41-42 and G64 Bug?q > > > > > > The small radius "is" the tool radius, and it was created by Linuxcnc > > when it created the G41 tool offset. > > > > > > ----- Original Message ----- > > > From: "Jim Craig"<[email protected]> > > > To:[email protected] > > > Sent: Friday, February 17, 2017 9:27:23 AM > > > Subject: Re: [Emc-users] G41-42 and G64 Bug?q > > > > > > Todd, > > > > > > Is the cutter radius larger than the small radius transitioning from > > > the straight line to the semicircle. would this cause the issue? > > > Grasping at straws here as I don't use G41/G42. > > > > > > I guess I don't understand why the small arc radius is being shown at > > > all in white if the below code is the programmed path. > > > > > > Jim > > > > > > On 2/16/2017 3:04 PM, Todd Zuercher wrote: > > >> Maybe, it is or isn't a problem. > > >> The g-code is only: > > >> > > >> G43 > > >> G0 X1.5 Y.375 Z1 > > >> G41 > > >> G1X1Y.5Z.5 > > >> G1X0.5 > > >> G2 X4.5 I2 J0 > > >> G1 X0.75 > > >> G0Z1 > > >> G40 > > >> > > >> It runs perfectly fine without the G41 reguardless of the G64 setting. > > I guess the planner must see that arc in the transition from one line to > > the next in G41 and the Q is acting it, even though it isn't actually > > written in the g-code. > > >> Something else to remember when using tool comp. > > > > ------------------------------------------------------------ > > ------------------ > > 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 > > ------------------------------------------------------------ > ------------------ > 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
