Aaron, Marius L. is right about current LinuxCNC behaviour, but I would not say so about "any CNC machine" when you can let some amount of error in your toolpath, what G64P..Q.. (BTW, I suggest using Q parameter too) should do, but it does not do much in LinuxCNC and your case actually yet. This is because it is limited to 2 moves of look-ahead only and keeps velocity low to be able to fully stop the machine at your set max accel values after those two lines of G code. This is like driving a car in a dense fog. The car could go much faster, but you can't because you don't see further safe distance you want to be able to stop. (Just a thought: how you could drive it if you would know by 100% there is nothing on your road?..)
To be straight, when I started using LinuxCNC (came from industrial machines, then Mach3 world which has big look-ahead capabilities) and I understood LinuxCNC look-ahead limitations, I was really upset. Maybe this is because I deal with 3D free-shape milling tasks mostly, which do have a lot of tiny segments, which make the toolpath and people who run those machines do count time as money.. But LinuxCNC people are trying to solve this problem and there are beta solutions in testing now. Look at thread "Tech demo of circular arc blending" on devel group. They got impressive results. And I can say this is the thing I am hoping and waiting from LinuxCNC most. And I hope it will not be limited to two or three axes / joints.. Another thing to try is NURBS G command. Marius Alksnys "aaron moore" <aaronmo...@linuxmail.org> wrote in message news:20131109131423.172...@gmx.com... > Marius > Thanks for your reply....makes sense. Does G64 p# work on rotary > files/systems? It didn't seem to when I ran it. > Do you have any tips for reducing the numer of moves in a job? > Sorry. I forgot to put a subject up top, > Aaron > ----- Original Message ----- > From: Marius Liebenberg > Sent: 11/09/13 11:17 AM > To: emc-users@lists.sourceforge.net > Subject: Re: [Emc-users] (no subject) > > Aaron When you cut stuff with a lot of little cuts, especially curved > cuts, the speed will always be slow. If you look at the constant velocity > parameters of any CNC machine you will find that the machine has to > accelerate and then decelerate again at the beginning and end of every cut > or move. Unless you have a very light gantry with a huge acceleration, you > will have a slow response. When the cuts are very short the machine does > not have enough time to get to the requested feed rate before it has to > slow down again. It is one of the pains of cutting 3D stuff. On 2013/11/09 > 12:58 PM, aaron moore wrote: > Hi > I am trying to get my head around > running a rotary axis on top of a 3 axis router, but I am having problems; > > > The main one is low feed speed. I have tried editing the code and inc > reasing feed and acceleration in the ini file to increase the speed, but > in makes no difference. I am trying to cut a helical final cut, which > seems to have lots of tiny moves, but other files I have tried are almost > as slow. Can any one offer some advice? The computer I run Lcnc on is very > old an slow, does that have any bearing? > Thanx in advance > Aaron ------------------------------------------------------------------------------ November Webinars for C, C++, Fortran Developers Accelerate application performance with scalable programming models. Explore techniques for threading, error checking, porting, and tuning. Get the most from the latest Intel processors and coprocessors. See abstracts and register http://pubads.g.doubleclick.net/gampad/clk?id=60136231&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
