Max Velocity and acceleration

[Jamy]

How do you know what max velocity and acceleration should be set in the configuration for a stepper motor? Also is there a Drill g-code that Z down fast till a certain height then slows down through the material then fast up and so on.

[TOTALLYRC]

Originally Posted by Jamy How do you know what max velocity and acceleration should be set in the configuration for a stepper motor? Also is there a Drill g-code that Z down fast till a certain height then slows down through the material then fast up and so on.

Trial and error. starrt at 10 ipm and 8in/sec/sec and increase you speeds untill it stalsl out. Back off by 10 to 20% to give a safety margin. Depending on the motors,drivers,screws and the phase of the moon, you may be able to go 12ipm or 1200ipm. That is why it is trial and error.

If you list what you have for components, I or one of the others can give you a ballpark based on what are experiences have been.

G83 is a peck drilling cycle and should do what you want.
If using mach3, look in the gcode list and see which parameters you need.


Mike

[Ceramic Man]

I'm interested in this too. I've got AC servo drives (not DC steppers) on my machine. They are SEM-29 motors coupled to ballscrews via cog belts. My machine has an "autotune" feature which runs the axes through tests and sets all the travel limits, max speed, acceleration, etc. However, rapid moves have some major accel/decel time where feed moves at high speeds are capable of going from max speed (230ipm) to 0 just about instantly. The accel/decel time is fine on X/Y (to prevent "banging"), but its kind of annoying when doing a peck-drill cycle. The Z-axis doesn't have a lot of weight or inertia going on (its a quill axis), so why the long accel/decel times?
Settings to change this on my Centroid controller are "Delta V-max" and "Deadstart". They are set to 3ipm and 5ipm respectively. Yes, they are both inches per minute. Deadstart is the minimum feedrate to decelerate to before an axis is allowed to reverse direction, but I don't really know what Delta V-max is. If it was acceleration, it would be inches per minute per minute.

Any info about this would be appreciated.