Re: [Machinekit] Motion stuttering in in the beginning of a large NGC file.

[schoone...@btinternet.com]

On 20/07/17 18:28, Seth Pierson wrote: I am seeing stuttering in the motion of my machine during the beginning of a run of a large(ish) ngc file. Here is a video showing the stuttering (starts at 10 seconds in): https://youtu.be/5vVM991b85s I have attached a file that shows the behavior. The stuttering happens on line 15 (G0 Z0.2) only. Once it gets past that move it is smooth sailing for the rest of the file (possibly because whatever causes the symptoms has finished by then). I also noted that if I let the machine run at 100% of its configured speed during that move, I sometimes get a following error. For now I have been setting the machine motion to ~10% for that one move then turning it all the way back up after. I think you have answered your own question, you are probably running with too high velocity and / or acceleration The Z axis is the heaviest in terms of load on the motors and forces acting upon it, on a mill.  Usually it is set 25% to 50% slower than X and Y. What often happens is that acceleration and velocity is set far too high, but because all the moves made are small, the speed never gets to a stage where it becomes a problem. Then a big retraction move, plunge or whatever and bang, the axis is moving for long enough to build to unsustainable rates and you get stuttering through missed steps, following errors and ruined work pieces. To test and also discount the outside possibility of mechanical binding on that axis, reduce all your velocity and acceleration figures by 50% at least and repeat. My SWAG is it will run perfectly, then you need to tune for the real world rather than theoretical maximums. I have a small mill of approximately the same dimensions as what I can see in the video, running with hardware step generation from a DE0-NANO My X and Y axis are MAX_VELOCITY =  25 , MAX_ACCELERATION = 100 and Z axis MAX_VELOCITY = 15 with same acceleration It will run smoothly all day unattended and never misses a beat. Are you expecting your mill to be need to exceed 1.5 metres per minute? If I truncate off of the rest of the file (except the ending stanzas) there is no stuttering in the motion. I have many large files that also have this same behavior. I suspect this to be related to the motion queue and/or the interpreter... Don't see how. Does anybody have advice on either how to mitigate this problem or where to dig to help solve it? -Seth -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to machinekit+unsubscr...@googlegroups.com. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout. -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to machinekit+unsubscr...@googlegroups.com. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout.