Problems Z AXIS, Motor a lot of noise and does not move

Hello everyone,

I have my MPCNC fully mounted, but I have a problem with the z axis.

When I move it the motor gets stuck and can’t move the axle.
My settings are as follows …
#define DEFAULT_AXIS_STEPS_PER_UNIT { 100, 100, 1600, 200 }

 * Default Max Feed Rate (mm/s)
 * Override with M203
 *                                      X, Y, Z, E0 [, E1[, E2...]]
#define DEFAULT_MAX_FEEDRATE          { 150, 150,30 , 24 }

//#define LIMITED_MAX_FR_EDITING        // Limit edit via M203 or LCD to DEFAULT_MAX_FEEDRATE * 2
  #define MAX_FEEDRATE_EDIT_VALUES    { 600, 600, 30, 50 } // ...or, set your own edit limits

 * Default Max Acceleration (change/s) change = mm/s
 * (Maximum start speed for accelerated moves)
 * Override with M201
 *                                      X, Y, Z, E0 [, E1[, E2...]]
#define DEFAULT_MAX_ACCELERATION      { 1000, 1000, 30, 3000 }

//#define LIMITED_MAX_ACCEL_EDITING     // Limit edit via M201 or LCD to DEFAULT_MAX_ACCELERATION * 2
  #define MAX_ACCEL_EDIT_VALUES       { 6000, 6000, 30, 20000 } // ...or, set your own edit limits
#define DEFAULT_ACCELERATION          1000    // X, Y, Z and E acceleration for printing moves
#define DEFAULT_RETRACT_ACCELERATION  3000    // E acceleration for retracts
#define DEFAULT_TRAVEL_ACCELERATION   1000    // X, Y, Z acceleration for travel (non printing) moves

I have noticed that if I lower the number of steps per mm to 800 the axis moves perfectly, but it would not be well configured, since it needs 1600 steps to move the axis 1mm.

I have tried to lower and raise the acceleration but it remains the same, it cannot move the axis

Can you help me with my problem?

Thank you

First, check the speed. At higher steps/mm, the less torque it has. Reduce your max Z speed to 4mm/s or less.

Second, double check the wiring.

Thank you very much for your help Jeffeb3

Correct, if I lower the number of steps/mm if it works, but then the machine does not move the axis the mm that I indicate from the screen or from the software.

Is there any other way to solve this problem ?, because really for the machine to move the axis 1mm I need the motor to take 1600 steps.

You should reduce the max feedrate, not the steps/mm.

I am assuming you have a 2 start leadscrew, instead of the normal 4. So it needs 4x the rotations to go the same height. The trouble is, that makes the stepper spin faster for the same mm/seconds… Steppers have the most torque at lower speeds, so you are losing enough torque that it is skipping steps. Slow down the speed (not the total distance) and you will get the right precision, but it will move slower.


Thanks a lot,

I have already made it work very well.

I have been downloading the freerate and it works perfectly.

Thank you very much for your help.

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