The Shop > CNC

The Basics: Stepper Motors

<< < (3/3)

Will_D:
Yet again PK many thanks for theses "nuggets of wisdom" that is what this thread is all about!

Joules:
There you go Will, I'm just too tight to buy these quality high voltage drivers and power supplies.  :D

Will_D:
And yet another question:

Leaving my controller (DDCSV1.1) on for a few hours I note that the motors are warm (say 40C) but not Hot!

Is this beacause they are in hold mode by default?

Note I have set hold current to 1/2 setting

John Stevenson:
Correct and this is fine.

PK:

Here is my ritual for tuning stepper motors. Be aware that reading this begins your initiation into my secret sect.
So, if your not too keen on initiation ceremonies then look away now.


* Pick a motor current.
* Set a low acceleration.
* Set a low velocity.('low ' here depends on your ballscrew pitch, for a 5mm pitch screw 500mm/min and 500mm/s/s would be low on most setups)

* Get the steps per <insert unit here> right. You should be able to calculate this, if your calculations don't match what you measure, then find the problem before proceeding.
* Write some G code that sends the Axis out and back. Put a dial gauge set to zero at one end.
* Crank up the velocity until the axis doesn't come back to the same spot.
* Set the velocity to 75% of that number.
* Crank up the acceleration until the axis doesn't come back to that spot.
* Set the acceleration to that number.(nb, if your machine will be used for full 3D work, do acceleration first).

* Next, and this is the bit that's relevant to this post, run the axis back and forth for at least 15 minutes for a NEMA23 (or just use it for a big job). If you can hold your hand on the motor then increase the current.
* When you are happy that all the motors max out at about 60degC. Re tune acceleration..

Navigation

[0] Message Index

[*] Previous page