Troubleshoot with the Z-axis motor

when i'm giving the command to Z-axis motor through pronterface it starts to vibrate and secondly when i press the Z-axis n stop button then it starts moving but only for 10mm not more then that no matter whatever is the command value for example 50 mm and it is not moving downwards and when i press z home on pronterface it only moves upward.
thanks
any reply will be highly appreciated.

the first thing to check is the stepper current without any information on what control board you are using I'll just going to guess its a RAMPS like board (most common in new builds). On the stepper driver you will see a little turn pot, turing this clockwise will increase the stepper current. You want about 80% of what the motor is rated to. Be careful when doing this as you may short the driver, I recommend doing it with the electronics off. You can check the current with an amp meter with the positive probe on the turnpot and the negative grounded. if you have NEMA 17 with 1.8 adeg you want about 0.4 to 0.6 Amp

Another thing you could try is turning the max federate down start in pronterface, halve the z mm/s and try to move the axis, if it runs smooth then you know your federate is too high, slowly increase your feedrate till it starts to stall again then drop in back down a little to determine your maximum federate, update this in your firmware. Be careful, one of the z federates is in mm/m (think its z homing).

As for the homing in the wrong direction, change the homing direction in the firmware, or just turn the motor pins 180

Edited 1 time(s). Last edit at 02/21/2017 04:39PM by scottybfg.

Arduino mega 2560 board is used in this printer and my Z-axis in not moving properly. and every time i give command of home z then it starts to vibrate and when i push the n stop button then it only moves 10 mm.

OK, by saying arduino mega 2560 im guessing you have a RAMPS shield on top.

Did you try increasing the stepper current on the Z stepper driver?

What host software are you using (the program you use to control the printer) If its pronterface you can lower the federate and see if that helps