2012/4/19 Stephen Dubovsky <smdubov...@gmail.com>: > > Around tight curves, that requires lots of short sections w/ > high changes in velocity. But you have to go slow within the limits of the > machine around those anyway.
Just like Andy said - if there is curve in the part, then that is why there are G2 and G3 commands in g-code. Period. Doing arcs with linear moves is _wrong_ approach by definition. Put G2/G3 commands in all arcs and let LinuxCNC do its job - slow down the machine, if necessary, so that it can take given acceleration limits and execute the path with max available velocity. > Like I asked: How big of a problem is this really? I guess that this is not the answer to Your question, but still... The task for CNC controller is to control the machine and move it so that it produces the part _exactly_ as described in the code operator feeds in it. The code has to be as simple and unambiguous as possible. If G1 is issued, then it is straight line. If the arc is needed, then use command for arcs instead of using one command in extremely inefficient way to describe another command. Task of CAM application is to produce that code. It should not reinvent the wheel, but use the standard commands from particular language. In case of g-code, G2 and G3 commands belong to the very very basics of this language. IMHO any CAM application, that does not use full potential of G2/G3 moves, is a crap, regardless of other features in it, because: 1) the code consist of such a small moves, that operator cannot understand it and cannot adjust it by hand, if needed; 2) the code is so long that moving around the file is just a disaster; 3) files for complex parts can exceed tenths of thousands of lines, which makes up the file size and also creates unnecessary load for the CNC controller, especially when it is loaded; 4) if such a basic commands have not been implemented, I think that there is serious reason to doubt the overall implementation of any other features, besides G1 moves... I think that in the end it is all about efficiency - smaller g-code file is easier for operator to overlook, easier for CNC controller to handle and efficient g-code leads to efficient work, as the job gets done faster. It seems like CAM authors are living on different planet, if they think that CNC controller should be equally efficient also with poor code. I think that this the same principle as give me Porsche 911 and ask to do a lap time as fast as Michael Schumacher. And then ask me, why was I so much slower, if I had the same car and in the same race track? Viesturs ------------------------------------------------------------------------------ For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
