G38.x and acceleration (not stopping)

had to try
unfortunately looks like no way to change those values

arhi wrote: had to try
unfortunately looks like no way to change those values

You can change them, then run a program. You just can't change them while a program is running.

Try issuing the commands from MDI.

will try that ... should help with G38 thing but not with everything else I wanted to use it for

arhi wrote: will try that ... should help with G38 thing but not with everything else I wanted to use it for

I am still failing to see why, if your Z-axis can achieve a higher acceleration than you have configured, you don't simply set the Z axis to use the high acceleration all the time?

not that simple, my axis can deal with high acceleration up to a certain speed... for e.g. I can drive XY @F500 without any acceleration (my original 3d print firmware don't support acceleration at all) but over F500 it will skip steps .. I need this "jerking" moves (infinite acceleration) while 3d printing in order to "break the string of plastic" so for some moves infinite acceleration is required, for some other moves the acceleration is required as higher speeds are achieved that way .. also I want to have a slow speed move with infinite acceleration and high speed move with regular acceleration... I can have 2 heads in the same time, one depositing plastic, other one depositing silicone, while I'm depositing plastic I have a stepper driving the extruder so acceleration on all 4 axes is working ok and in sync, on the other hand for silicone I have on/off pressure valve and constant extrusion rate so can't have acceleration on the XY axes, it has to be uniform from start to stop, yes that requires slower move but it works .. now since the idea is to use both heads in the same print - first the plastic head make a scafold for few layers then silicone head fills it I need to be able to change acceleration mid print (hence those M20x codes I mention we normally use on printers) ... now for milling I doubt this is needed but I would like to move my printing to linuxcnc as well as I'm sure printing would benefit from better speeds I see linuxcnc is able to achieve (looking forward on how pats look like and adapting speed in corners etc..) + changing reconnecting motors from linuxcnc box to a reprap box is crap I already replaced 2 connectors

can drive XY @F500 without any acceleration (my original 3d print firmware don't support acceleration at all) but over F500 it will skip steps

Sounds like the best solution would be more powerful steppers / drivers to achieve the acceleration / speed you are looking for. Possible also look if you are using microstepping and go to a lower setting there.

Infinite acceleration is not really possible, always going to be limited by the machine.

Rick G