My comments are interspersed in the body. On Thu, Apr 15, 2021 at 6:03 AM andy pugh <bodge...@gmail.com> wrote:
> On Thu, 15 Apr 2021 at 05:49, Stuart Stevenson <stus...@gmail.com> wrote: > > > My current attention to the project is driven by my desire to have 5 > axis > > cutter diameter compensation in LinuxCNC. > > I think that there is an argument that this is better done in the CAM > as it has a much better idea where the material is, and can handle > non-cylindrical cutters. > Not that I am against the idea of it being doable in the controller, I > just think that it won't see much use. > Use a barrel cutter as an example. If you resharpen a barrel cutter and take .02 off the diameter you have now created a completely different cutter than what was used in the CAM system to generate the program. That would necessitate generating a new program if you wanted to create a correct part. I tend to agree with your use comment. This capability may not generate a lot of use but the 5 axis world has grown a LOT in the last 10 years. If you want a place at the 5 axis table you need 5 axis capability. Prospective users still question whether LinuxCNC has 2D CDC. :) Recently, I was talking to a shop owner about LinuxCNC. He only wanted to talk about Tool Point Control. When I told him LinuxCNC could to that was when he allowed me to show him the LinuxCNC website. He would not have considered LinuxCNC before as it is JUST a 2D bit player. He had researched almost all other controls but had not looked at LinuxCNC. He now wants LinuxCNC on his 5 axis machines. The (Covid) slowdown has put his desire on hold. I would like to have 5 axis CDC implemented before he wants the retrofit done. The shop owner's hesitancy was caused by the name LinuxCNC. The use of the term Linux gave him the idea of a less than capable control. > > Circular interpolation is also an area to be simplified. G17, G18 and > G19 > > can be eliminated. They would have to stay so legacy programs would still > > function. I would implement G02/G03 as follows: > > G02/G03 X Y Z I J K F would circle the tool around a vector perpendicular > > to a plane described by the IJ values combined with the XY start point > > It might be simpler to just define the centre point with IJK and > eliminate the explicit plane entirely. I think that start, centre and > end defines a circular arc in 3D space completely?) > Start, Center and End points do describe the circular arc unless you are talking about a full circle or half circle. Using the third value of I J K allows you to use a full circle or half circle or even an arbitrary plane to describe the circle. The arbitrary circle would not necessarily be perpendicular to the tool axis. > The interpreter could learn to use the new-style arc whenever it sees > all three of IJK. Or, alternatively, we could use the currently unused > G16 code to mean "arbitrary planes" > (G16 means "Polar coordinates" in Fanuc, but LinuxCNC uses @ and ^ for > that. If clashing with Fanuc is a problem then G19.9 could be used.) > I think that I prefer an INI entry in [TRAJ] that turns accepting all > of IJK in an M2 / M3 on and off. > > I don't think clashing with Fanuc is a problem at all. > Note that there is already an old branch that attempted arbittrary arcs > https://github.com/LinuxCNC/linuxcnc/tree/arbitrary-arc > You can see the chages here: > > https://github.com/LinuxCNC/linuxcnc/commit/0fc41d50c1bce2bdecc8a90e6e5057af5153d66f > This used a "magic comment" to define the curve, but it can be seen > that it is pretty much the same input data as suggested above. > > I like to have a magic button on the bottom of my keyboard. The button is called the IFM button. It's F'n Magic. :) It has the same function as the Staple's red 'EASY' button. thanks Stuart > -- > atp > "A motorcycle is a bicycle with a pandemonium attachment and is > designed for the especial use of mechanical geniuses, daredevils and > lunatics." > — George Fitch, Atlanta Constitution Newspaper, 1912 > > > _______________________________________________ > Emc-developers mailing list > Emc-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-developers > -- Addressee is the intended audience. If you are not the addressee then my consent is not given for you to read this email furthermore it is my wish you would close this without saving or reading, and cease and desist from saving or opening my private correspondence. Thank you for honoring my wish. _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
