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Prusa connected and motors moving

Posted by owbridmark 
Prusa connected and motors moving
April 14, 2012 04:08AM
I have got my prusa connected and my motors moving after a lot of hard work and research!

Thanks to everyone wo has helped me out. The only thing that is needed to do is wire my extruder/thermistor.

My motors are also moving the opposite way to what they should be so I may have to re wire them.

Also my Z axis is jittering a bit as it moves up and down. I am not sure if it is because it is not level or what but I might have a look at it. Any advise is welcomed. Other than that my x axis moves primo and so does the y.

I am looking forward to building a shot glass (or more) to toast my printer. Might have to get a bit messy after al this hard work.
Re: Prusa connected and motors moving
April 14, 2012 05:03AM
If you motor wires have the black style connector, it can just be turn around 180 and plugged back in. (wont work with the white or red keyed connectors) NB only disconnect and reconnect motors with the power off, or you may blow a stepper driver

Or you can set the inverse flag in the firmware.

Z could be leveling, do you Z threaded rods stay straight or do they oscillate?
Or it could be power, have you tuned the variable resistor on the stepper drivers?
Re: Prusa connected and motors moving
April 14, 2012 06:02AM
Thanks for the quick reply. I have worked out how to turn my motors around just fine. I have the white molex connectors but just turned power off, pulled the crimps out and flipped them around the other way and worked fine.

My right threaded rod oscillates a bit. The z motors seem to skip sometimes though. I think they seem to be working down the bottom better but it is hard to tell.

I have not tuned the variable resistor on the stepper drivers. Is that the little screw on them? How much should I turn it if so? Also can I turn it too far or wreck anything whilst tuning it?
Re: Prusa connected and motors moving
April 14, 2012 06:37AM
yes its thats it. It controls how much power the steppers get.

Skipping is a good indication of not enough power.

The standard way it to turn it all the way down (anti clockwise) then slowly turn it up (clockwise) till the moters move (they wont at first) then give it an extra 1/8 of a turn

If its to high the stepper will get to warm, the stepper drivers could start screaming and or the steppers may make a ticking sound. For a short while this is fine, but per longed the stepper drivers will probably over heat and die.

If you find that you have to turn this up to high (over about 2/3s) then you probably have a mechanical issue to find and fix.

NB use a plastic screwdriver for this, or switch off every time you adjust it (you dont want to short anything with a metal screwdriver, that would also result in a dead stepper driver)
Re: Prusa connected and motors moving
April 14, 2012 08:16AM
Thanks champ,

I'll try fix it by checking everything is level/parallel 1st and if I can't fix it that way I will try the tuning of the variable resistor.
Re: Prusa connected and motors moving
April 14, 2012 05:07PM
I also put a bit of grease on my Z threaded rods it makes them work smoother


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Experimenting in 3D in New Zealand
Re: Prusa connected and motors moving
April 15, 2012 05:50PM
Cheers for the tip. Do you think if I removed the threaded rods and ran a die down it this might help also? Or do you not think it is worth it?
Re: Prusa connected and motors moving
April 15, 2012 09:33PM
I usually run a nut down them, but a die would work, so far I haven't found it needed it though


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Experimenting in 3D in New Zealand
Re: Prusa connected and motors moving
April 16, 2012 02:06AM
One thing I found the hard way is don't use Zink coated m8 on the Z, its to rough and produces to much friction.

Use stainless steel m8 on Z if you can.
Re: Prusa connected and motors moving
April 17, 2012 01:47AM
Thanks Dust,

I have zinc nuts so I might change them out. It's good to hear everyones opinions because sometimes issues like this can be combinations of things causing the problem.

I had it working last night for a little bit and it was going fine. Then I fiddled with something in my firmware... I think I might try re-installing it to revert back to the default settings and work my way from there again.
Re: Prusa connected and motors moving
April 17, 2012 03:29AM
I have made about a dozen Prusa now all with zinc threaded rods and they all work well with a bit of grease, or at least nobody has complained so far


__________________________________________________________________________
Experimenting in 3D in New Zealand
Re: Prusa connected and motors moving
April 11, 2013 05:48AM
I have zinc nuts so I might change them out.





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Diablo 3 Gold;Aion Kinah Kaufen;cheap runescape gold;WOW Gold
Re: Prusa connected and motors moving
April 12, 2013 12:05AM
Hi Mark,
You really should get a multimeter and set the stepper drivers to a specific current by measuring the Vref. Refer to the information on the Pololu website for how to do this.
What Steppers are you using? and How have you wired them up? Series or Parallel?

You should definitely lubricate the threaded rod with some grease.
Cheers,
Mike P


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