Adding an extra Y motor - need an extra stepper controller?

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lasershark1
Posts: 143
Joined: Sun Apr 22, 2012 1:52 am

Adding an extra Y motor - need an extra stepper controller?

Post by lasershark1 » Mon Apr 23, 2012 3:37 pm

I'm already planning the expansion of my Shapeoko, and I've read I'll want to add another motor to the Y axis. Will that require a 4th stepper controller, or can both Y be controlled from the same controller?

I'm asking because I'm about to buy my shield, and the grblshield only has 3 controllers... if I'll need a 4th (and I'm sure I will very soon, I've already ordered an extra stepper motor for the upcoming expansion) I'll keep looking for another option - I dont want to spend the money on a grblshield and then wind up needing a 4th controller anyway.

RedOko
Posts: 43
Joined: Mon Apr 09, 2012 5:49 pm
Location: TX

Re: Adding an extra Y motor - need an extra stepper controll

Post by RedOko » Mon Apr 23, 2012 4:38 pm

What is recommended is to actually distribute the force to both sides to prevent skewing the Y axis.

This can be done by 2 ways.

1. Adding a 2nd motor. Its recommended to have a 1 driver to 1 motor and just split the signal, but IIRC, somebody split the power coming from 1 driver to 2 motor.

2. Transmit some from the first motor to the other side by means of a shaft. This is my plan for an upgrade but I will mount the motor to the main frame to lighten up the main gantry and use a long shaft to turn 2 pulley. Sorry I have no pictures of my plan.

Luis
Luis
aka "RedOko"

levlandau2
Posts: 187
Joined: Tue Apr 17, 2012 1:52 am
Location: Minneapolis, MN, USA

Re: Adding an extra Y motor - need an extra stepper controll

Post by levlandau2 » Mon Apr 23, 2012 5:41 pm

This is a very good question, that I have not heard a satisfactory answer to.

From what I have read, it is possible to drive two stepper motors with one driver, but one has to be careful about running too much current through the driver and blowing it.

I would guess that the best option would be to buy a stepper shield which can handle 4 drivers and thus 4 motors. However grblshield only supports 2. A possible options is TinyG although it is quite pricey at $122.

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