I expanded my k40 to a 12x24 inch bed with a 16 inch Z axis. I’m using one of the original stepper motors from the k40 to drive the z axis. is 100 mm/s the max that the Z can go in the software? I try changing values in the smoothieware trying to change the step config and such but nothing changes. I have a 20 tooth drive to a 80 tooth driven so the bed only moves about 1 mm vertically per 100 mm movement.
I changed the z steps per mm to 2000000. It sped up some. Move speed to 1 mm/s I. The program and upped the current to 1.2. But I can’t get it to calibrate correct. It goes 40 mm for a 100mm move used the formula to correct and I’m up to 160000000 and it is the same. Is there a point we’re it doesn’t change or I go to far. I guess the correct t movement doesn’t matter for what I want just the speed but just wondering. Thank you.
On the contrary, correctly calibrating the axis is required for it to work correctly.
The motor has 200 (full) step/rev.
With a 1:4 stepdown, the motor must move 800 (full) steps to turn the leadscrew one revolution.
You already set the stepper motor driver to a specific number of microsteps per full motor step. Multiply 800 (full) step/rev by the microstep setting to get the step/rev value at the leadscrew.
You know how much the Z axis moves per leadscrew turn, which is the screw’s lead. Leadscrews typically have multiple starts, so the lead need not equal the pitch.
Divide the leadscrew’s step/turn value by its mm/turn value to get the step/mm value = how many motor steps will move the leadscrew 1 mm.
For example:
- 200 (full) step/rev motor
- 1:4 gear stepdown
- 8 microstep/full step
- 4 mm/turn lead
6400 step/turn = 200 × 4 × 8
1600 step/mm = 6400 / 4
Set the Z axis accordingly, set the maximum speed to about 400 mm/min, and see if the axis behaves correctly.
Follow @ednisley advice and if I’m not mistaken, that 160000000 takes 33bits. I believe most of these dsp are 32bit. You might have reached the limit… I have no idea, just speculation.
Can you read it back from the controller and ensure it’s actually storing that value?
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