On Thursday 04 March 2010, Rudy du Preez wrote: >I have a general question about the throughput of EMC2 and what determines >it. I friend is using nurb modeling to describe the shapes that he has to >mill in soft material. So far he has had disappointing results using EMC2 > in that the processing of the large gcode files with many short vectors > and the resulting cutting speed is too low. For most cutting moves the > programmed speed of the axes is not reached in these applications. Jogging > speeds on the machine is fine. Where does the problem lie? > >In playing with parameters such as base_thread, we found that these have >some influence on the troughput and cutting speed. The processing power and >latency of the PC also comes into play. It seems that careful tuning and >balancing of some parameters is required. The problem is to know which ones >will improve the situation best. The steppers are currently driven via the >parallel ports. A MESA 5i20 card is planned to replace this. > >Has anybody been working on the limited throughput situation? > >Rudy > I don't know if there is a one true way to attack this. I run steppers too, and found quite some time back that if I were willing to give up on acceleration and use a gentler accel setting, the top speed achievable was considerably higher. However corner blending considerations will then slow it down because of the gentler accelerations being used. Without some very strong, low inertia servo's, my method seems to be the best for my work, where I often cut one-sie's, and may spend a day cutting air before actually making the part, but once the mill starts throwing chips, the part is generally usable.
YMMV of course. If, OTOH, your cutting speed is limited by available spindle power and rpms, as mine is, one might want to up the accel's and give away top speed. You can, for the most part, reverse a nema 23 stepper that isn't moving a 20 tpi screw at more than a couple of inches/minute very quickly, but you cannot extend that violent an accel to more than that same couple of ipm without encountering a stall. And there goes that part, its usually wrecked. I've had it dancing on the table a few times, but not now, and its much more dependable this way. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Life is fraught with opportunities to keep your mouth shut. ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
