Dual Z motor not running correctly

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atrueresistance
Posts: 151
Joined: Thu Feb 07, 2013 6:20 pm

Dual Z motor not running correctly

Post by atrueresistance » Sat Mar 09, 2013 8:04 pm

I have the Dual Z motor configuration from the inventables upgrade kit. The problem is running 2 motors seems to be too much for the grblShield.

I started with the trim pot set all the way down, and only when I hit all the way up, do the motors start to move, plus I don't think they should sound like that.


The power supply is putting out 24.11V.

Wiring
From shield >>Motor 1>>Motor 2
RED-----------RED----------BLUE
BLUE----------BLUE--------RED
BLACK--------BLACK------GREEN
GREEN--------GREEN------BLACK

Is anyone else having this problem?
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cvoinescu
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Re: Dual Z motor not running correctly

Post by cvoinescu » Sat Mar 09, 2013 10:55 pm

It's worth trying the series connection instead. Check out this post explaining the advantages and disadvantages, and this post that gives the wiring diagram.

Edit: note that you have your motors wired to turn in the same direction. Swap only one pair if you want them to turn in opposite directions. For example:
RED-----------RED----------BLUE
BLUE----------BLUE--------RED
BLACK--------BLACK------BLACK
GREEN--------GREEN------GREEN
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millerdlca
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Location: Edmonton, Canada

Re: Dual Z motor not running correctly

Post by millerdlca » Sat Mar 09, 2013 11:09 pm

Your wiring is wrong (also, by convention that is the Y axis, not the Z axis). You are reversing both coils, which means that the motors will be turning in the same direction and fighting one another. Just reverse one pair of wires. Like so:

From shield >>Motor 1>>Motor 2
RED-----------RED----------BLUE
BLUE----------BLUE--------RED
BLACK--------BLACK------BLACK
GREEN--------GREEN------GREEN

OR

From shield >>Motor 1>>Motor 2
RED-----------RED----------RED
BLUE----------BLUE--------BLUE
BLACK--------BLACK------GREEN
GREEN--------GREEN------BLACK

If you want to prove it to yourself, you can release one or both of the belts and you should be able to see that they are turning the wrong way.

Dennis

ejs
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Re: Dual Z motor not running correctly

Post by ejs » Sat Mar 09, 2013 11:31 pm

The previous posts are correct. But the issue with them is that you would only be having issue and terrible sounds with your motors fighting each other if you had the belts installed. Which they are not in the video. It should not sound like that--I'd double check the specs for your motors and make sure your coils are being activated in pairs as expected. Also, are the motors the same number of steps per rev? Are they matched up in terms of voltage and power? Same max torque? Rearranging motors so that those on either side are twins may be the ticket. That may mean swapping the new motor with the one currently on the Z-axis.

If taking this advice or the advice above doesn't work I would suggest the Buildlog stepper shield which drives each side of the Y-axis individually. You can use different powered motors, though they still have to have the same steps per rev for GRBL to drive them correctly.

Full disclosure, I produce and sell the Buildlog CNC Shield. Though it's worth noting that I use it with my Double Y setup and adore the power it puts out. Thanks for the post. Thinking through your issue helped me finalize one of the many design decisions for the new version of the shield ;)
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atrueresistance
Posts: 151
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Re: Dual Z motor not running correctly

Post by atrueresistance » Sun Mar 10, 2013 1:01 am

All 4 motors were from inventables. NEMA 17. I'll try wiring it different. So far I just skipped ahead and went with 1 for the "Hello World print" Took me a little bit. I learned I had a bunch of stuff out of place x,y,and z positions were not wired correctly :lol: Noob mistake.

I've noticed there is a little bit of play with the gantry. With my pen zip tied to the Correct z I can pull up and the whole x assembly will move created unwanted lines in a design. You can see every entry point in this picture.

http://imgur.com/fi0v8cf

All 4 of the bolts are tight, can I tighten them more? as this might compress the nylon spacers too much.
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atrueresistance
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Re: Dual Z motor not running correctly

Post by atrueresistance » Sun Mar 10, 2013 2:13 am

Twisting the spacer fixed the wobble
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atrueresistance
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Re: Dual Z motor not running correctly

Post by atrueresistance » Tue Mar 12, 2013 11:40 pm

millerdlca wrote:
From shield >>Motor 1>>Motor 2
RED-----------RED----------RED
BLUE----------BLUE--------BLUE
BLACK--------BLACK------GREEN
GREEN--------GREEN------BLACK
This worked like a charm. I had to up the voltage. Thanks
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