Build Your Own SLA/SLS

I'm using a RAMPS controller and a NEMA 17 motor.

When its connected to the z-axis spindle and I try to move it 1mm it just slips and vibrates.

Without it connected to my Z axis spindle and I hold it with my fingers and move 1mm, it turns fine both directions. If I apply a small amount of pressure with my fingers then it slips.

Any ideas why this appears to have such little power?

What are your stepper motor specs? Have you adjusted your stepper driver properly?

I'm starting to get somewhere. I adjusted the pot on the stepper driver and it increased the power. I also noticed the spindle was a little tight when the top plate was tightened and also when the linear block is screwed into the spindle. I loosened these and it worked fine. I will try to add some washers to adjust the height and the distance of the blockl and tighten to see if this allows it to move freely.

maybe the motor current of your microstepping driver is just way too low. Check with the motor data sheet and adjust accordingly.

stepper motors slipping or not moving or irratic etc , is mostly down to either trying to run the stepper at a higher speed than it's capable of
this can manifest it's self in many ways .

such as low voltage , not enough current , incorrect setup between what you have the stepper driver set for and the actual step pulses
i.e setting the software for for say 1/8 step and having the actual hardware set for 16 microsteps .

ideally for steppers you want the highest voltage for the stepper driver spec and around 3A for each stepper your using
most stepper drivers can accept upwards of 24v , and with the advent of modern stepper drivers they take care of the current rating
put very simply voltage gives you speed , amps gives you holding torque for the position .

however there is a trade off the higher the microstepping the lower the torque available ,to overcome z axis forces of gravity etc
this will show it's self as slipping downwards , especially if a fast move or high acceleration

if ever your faced with a stepper that seems to slip , modify your step rate and acceleration , by reducing by 50 % and try again
once you have it working correctly then you can bring the speed up in stages

hope this helps people understand steppers a little bit more