There are limits in trajectory planner adjustable in .ini file DEFAULT_ACCELERATION= and MAX_ACCELERATION= you tried them?
> Hi again, > Indeed it is pretty hard to use spindle load if is doesn't change thru > the corner. I suspect it does on smaller machines but that is not a > generalized solution. > Just for experimental purposes it might be interesting to decrease the > velocity thru a corner see if it helps. Lacking the adding another row > to the matrix should control jerk but the may not be the whole solution > when dealing with a change in direction. So much to learn so little time > (and energy). > I suspect the 'big boys' do some pretty fancy adaptation to get good > smoothing thru the corners. Of course it is all propitiatory and those > patents take a long time to run out. Silvia McFarland (sp?) in her > masters thesis (Uni BC) used sin accel rather than trapezoidal. Might > help. I think traj control get much more critical as velocities get > really radical. Some of the new Brothers with 30 tapers absolutely > scream. When the machinist describes stepping back from the machine when > the tool moves toward him then is must be really impressive. > > Dave > > On 9/21/20 4:55 PM, andrew beck wrote: > > hey dave > > > > I hear you. I might get good at coding myself soon.. but would love to > > solve the problem. > > > > I don't think the spindle load could really help much though. > > > > I am machining plastic and aluminium and the spindle load doesn't > > noticeably change in corners. I more need a limit on the initial > > acceleration for a split second I suppose > > > > or go the full way and have something that analyzes the G code path and > > calculates the best speed and path for the machine > > > > regards > > > > Andrew > > > > regards > > > > > > > > On Tue, Sep 22, 2020 at 11:35 AM dave engvall <[email protected]> wrote: > > > >> HI Andrew, > >> Just because I have ideas does not imply I can implement them. ;-) > >> However, I believe there is a velocity pin that might be used to slow > >> down in corners. Since the spindle loads up going thru corners it may be > >> possible to monitor spindle load and back off velocity thru the corner > >> which should make milling a bit smoother. Adding jerk control involves , > >> as you know, adding another order to motion. (see first sentence). ;-) > >> A lot of bright people are involved in linuxcnc but they all have their > >> own pet projects. Just the way it goes. > >> Hang in there, your heart is in the right place. > >> > >> Dave > >> > >> On 9/20/20 8:19 PM, andrew beck wrote: > >>> Hey guys > >>> > >>> just a few thoughts here. > >>> > >>> I have a high speed cnc machining center (cnc mill) > >>> > >>> it has 16mm pitch ballscrews and weighs 6ton > >>> > >>> linuxcnc is awesome and does a great job controlling it. I make plastic > >>> injection molds and lots of 3d machining all the time. plus all the > >> little > >>> jobs that a cnc is great for. > >>> > >>> I think the only thing lacking from linuxcnc for my use is some sort of > >>> jerk control for corners. there may already be something around that > >>> solves the issue though without jerk control. so what happens is when > >> the > >>> machine changes direction the whole machine vibrates and jumps around. > >> its > >>> quite bad. enough that I may rubber mount the electrical box lol. > >>> > >>> I have accelerations of 750 (i think it is mm/sec2) > >>> > >>> and max rapids of 8m/min > >>> > >>> I would love to turn those up to like 25m/min rapid and 2000mm/sec2 > >>> accelerations > >>> > >>> has any one tried any form of jerk control yet on linuxcnc? or wants to > >>> have a play and code it. I have 3 6 ton cnc machines that will all use > >>> linuxcnc so very keen to solve this jerk control issue. > >>> > >>> regards > >>> > >>> Andrew _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
