delta 3d printer help

Hi
I am having some issues with my 3d printer and I cannot figure out how to fix them. It is a Reprap Rostock delta 3d printer running on a smoothieboard.
The first problem is that the calibration points do not work as they should. have the printer go to point X0 Y0 and Z0 the hotend will be a couple of millimeters of the the print bed, but when I go to print and it goes to the perfect height for the first layer, it goes to Z0.4 to print. I mainly want to fix this because I need to calibrate the corners because one is a litttle low.
The next problem I have is the print platform keeps shifting as it prints I have tried to reduce the current of the steppers and it is a 0.15amps per motor and it still skips, should I try to increase the current? I notice that the motors get hot to the touch even with the motors set to 0.15 amps.
I also notice it always shift toward the x axis motor tower. All of the axes move very easily.
Thanks for the help
Tanner

I can't advise you on how to configure a Smoothieboard. However, if your motors are running hot at only 0.15A current, then it sounds to me that you have the wrong motors. Can you provide a link to the motor specification?

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Here is a link to the motors
http://www.ebay.com/itm/NEMA17-17-Stepper-Motor-36oz-in-2600g-cm-3D-Printer-RepRap-Medel-Prusa-/331084351443
If these are not good what would be a good replacement to these motors?

Assuming the specification is correct, those motors are not very suitable because they are rated 0.4A and 12V. For all normal 3D printer electronics, you should be looking for about 1.5A and 3V. You need a lot of voltage headroom to get good movement speed.

I am surprised that the motors are getting hot at only 0.15A. They will get hot at their rated current of 0.4A, but at 0.15A they should be cool.

I don't advise you to run them at 0.4A, but at 0.3A they ought to be OK. So try increasing the current. If they get too hot to touch, turn the current down again.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I tried that setting on the printer and it still skips like it is either over or under powered, would it be that the voltage provided is not 12 volt required by the stepper motor, most motors used are 3V motors.
I have also been considering upgrading stepper motors on the printer.
Would these be good motors?
Sparkfun nema 17 stepper motor
Thanks
Tanner

Those are the motors in the Folger kits, and while mine ran a bit hot at rated settings, they should have plenty of power. Running a VRef of .3v on a Chinese Pololu holds the heat down some, but still seems to run OK. Folger suggests a VRef of .35v, which ran pretty well, but deformed my printed parts . . . I can't fathom anything but 'epic fail' at .15A, which would correspond to a VRef of .125v, if my math is correct. What specific driver VRef have you set?

- Tim