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. > > > ----- Original Message ----- > From: "sam sokolik" <[email protected]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Sent: Thursday, February 16, 2017 3:20:02 PM > Subject: Re: [Emc-users] G41-42 and G64 Bug? > > On this post - I showed what happens to a shape as you increase Q > > http://www.cnczone.com/forums/linuxcnc-formerly-emc2-/206712-software.html#post1453562 > > sam > > On 2/16/2017 2:11 PM, Kurt Jacobson wrote: >> OK, I see that you mean now. As they say, a picture is worth a thousand >> words. (Though that does not seem to hold true when writing an essay for >> English class!?) >> >> I still think naive cam detector is doing exactly what it is suposed to. If >> the maximum deviation of an arc from a strait line is within Q they are >> collapsed into a single linear move, which is exactly what I see in your >> screen dump. >> >> Kurt >> >> On Thu, Feb 16, 2017 at 2:53 PM, Todd Zuercher <[email protected]> >> wrote: >> >>> I didn't expect the Naive cam detection to do this. >>> https://s2.postimg.org/ezy3wjfjt/bug.png >>> Maybe I am reading the docs wrong. >>> >>> ----- Original Message ----- >>> From: "Kurt Jacobson" <[email protected]> >>> To: "Enhanced Machine Controller (EMC)" <[email protected]> >>> Sent: Thursday, February 16, 2017 2:10:26 PM >>> Subject: Re: [Emc-users] G41-42 and G64 Bug? >>> >>> I don't really know any thing about this, but I'd say that is the expected >>> behavior based on the description of G64 Path Blending: >>> >>> "On G2/G3 moves in the G17 (XY) plane when the maximum deviation of an arc >>> from a straight line is less than the G64 P- tolerance the arc is broken >>> into two lines (from start of arc to midpoint, and from midpoint to end). >>> those lines are then subject to the naive cam algorithm for lines.[1]" >>> >>> It sounds like your Q value is larger than the radius of your compensation >>> lead out, so the arc is broken up into two line segments. Since these line >>> segments are within Q of a linear move they are collapsed into one linear >>> move, and since this linear move is within Q of the original linear move >>> the whole path is collapsed in to a single linear move which is treated >>> essentially becomes a long compensation lead out move. >>> >>> Just thinking out loud here, again, I am a complete noob so take this with >>> half a grain of salt. >>> >>> [1] http://linuxcnc.org/docs/html/gcode/g-code.html#gcode:g61-g61.1 >>> >>> Kurt >>> >>> On Thu, Feb 16, 2017 at 1:32 PM, Todd Zuercher <[email protected]> >>> wrote: >>> >>>> I was playing arround with G41 and G42 in a simulation and I think I >>> might >>>> have found a bug with the Naive CAM Detection. >>>> The shape I was simulating was a semi circle with the start/end point on >>>> the flat side and a single G2 arc move connecting the end points. >>>> The simulation behaves strangely. With a tool radius of .125" and .25" >>> and >>>> staight G64 the tool path precisely followed the path (white and red >>> lines >>>> over lapped). With G64P0.001, the same. The expected behavior is cutting >>> a >>>> straight line parallel to the programed line offset the tool radius, cut >>> an >>>> arc around that end point to connect to the offset path of the commanded >>>> arc cut. all good right. >>>> With G64P0.001Q0.2 there is odd behavior. It moves in a straight line >>> from >>>> the beginning of the compensated straight line cut to the begining of the >>>> compensated arc cut completely ignoring the compensated end point of the >>>> straight cut. I know having such a large Q setting is a little odd. I >>> also >>>> see simular behavior with G64P0.2 (no Q specified, same as Q0.2) only >>> with >>>> more rounded corners. >>>> I seem to see the odd behavior when ever Q is about 2/3 or more than the >>>> tool diameter. >>>> >>>> -- >>>> >>>> ======================================== >>>> >>>> Todd Zuercher >>>> mailto:[email protected] >>>> >>>> ======================================== >>>> ------------------------------------------------------------ >>>> ------------------ >>>> 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 >> >> > > ------------------------------------------------------------------------------ > 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
