Hi. I have been using slicer for a while but what does acceleration control do? For me they are defaut 0.

Use your Tooltip and place cursor over field or text if not enabled.

It says high values like 9000 gives good results, but what does it really do? How does it effect on printing.

It probably does what it says: Change your acceleration settings, probably by issuing a M204 command where you have told it to do.
Why should you? I do not know.....Why not test and see for yourself, that is what experimental version is for?

Edited 1 time(s). Last edit at 12/01/2014 07:27AM by justcurious.

Like a car, the print XY position cannot move instantly from standstill to the set move speed, nor can it stop instantly. The rate of change of speed is the acceleration. If it is set too high, your stepper motors will probably start skipping steps, or belt stretch will distort the print. If set too low the print time will be a lot longer than necessary. The acceleration is set as a default value in the printer's controller to suit the printer's mechanics, and will normally never need changing. If however you have a print that is unusually tall and thin and the printer has a moving bed, you may want to decrease the acceleration to prevent the bed movement causing the top of the print to sway or even fall over (note it is acceleration rather than speed that causes such "jerking"). In some cases a lower acceleration is beneficial for bridging. It is not however a parameter you will usually have any need to change.

Dave