extruder stepper making awful noises

Check out this video I recorded of my problem: http://www.youtube.com/watch?v=TIqCIosUD_M

Basically my extruder stepper turns for a few seconds when I click the extrude button, however it makes awful buzzing, clicking and whining noises. I'm using a MakerBot extruder board (with the reprap modifications) running the FiveD firmware and the RepRap host software to test it. I tried adjusting the pot and it doesn't make any difference with the awful noises, but if I set it too low it stops turning. The motor I'm using is a Lin Engineering 24M014 it's rated 2A and 1.2ohm. Here's the specs: http://www.alltronics.com/mas_assets/acrobat/24M014.pdf

I had asked on irc and the consensus was that I should try a different firmware or use a separate stepper board, but I don't understand why my setup isn't working. I'm using the same motor for the other axis controlled by MakerBot stepper boards and they work fine. It's just the extruder board controlled motor that isn't happy. One person on irc said it sounds like the extruder board isn't capable of giving it enough power, but I didn't see anything in the wiki anywhere saying you need a lower powered stepper for the extruder? Is the extruder board really incapable of giving enough power or could it be that I'm not giving the entire system enough power? I am using a 12V 5A power supply, and not an ATX power supply.

I was looking through the extruder firmware code and saw a comment about how it's dividing the pot value by 4 which "is about right for a 1A 3-ohm/coil stepper". Could that be the problem?

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Tony Buser http://tonybuser.com * http://reprap.org/wiki/User:Tbuser#Projects

I've gotten the "horrible buzzing" when the values in my machines.xml file were way off. Using 5/16" Stainless all thread Z axis lead screws on my Mendel and hacking my own machines.xml values caused the problem. Resetting the steps value to lower values fixed it for me. Could this help?

The extruder stepper will make a high pitch whine because the PWM frequency is in the audio range. I asked Adrian about this this recently and this was his reply:

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Yes - about 8 KHz from memory; making it ultrasonic would mess up lots of Arduino timings :-(

Because of the gearing the stepper doesn't need a lot of current, so it shouldn't be loud.

Not sure about the not needing lots of current. I need to put 1.5A through my extruder steppers but as usual the laws of physics seem more favourable in Bath. Fortunately I don't use these electronics so my steppers don't whine.

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[www.hydraraptor.blogspot.com]

Hm, ok so I might have to live with the whine, but what about the clicking? Is it normal for it to make that loud clicking sound while it is turning and extruding? The sound coming from the motor sounds like a card stuck in the spokes of a bicycle.

I ordered a Pololu A4983 Stepper Motor Driver from MakerGear to try, but I'd really like to figure this out and try to get it working right with the extruder controller.

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Tony Buser http://tonybuser.com * http://reprap.org/wiki/User:Tbuser#Projects

Yes I think the clicking sound is simply the motor stepping. Possibly you have a bit of backlash in the gears allowing them to rattle against each other. Try sliding the motor closer and see it it gets quieter. Also it is good idea to put lithium grease on the gears to reduce the wear.

I use micro stepping which is much smoother and makes a humming should rather than clicking unless it is going very slowly. The steps are 8 or 16 times smaller so much quieter. The A4983 should solve your noise problems and also make better prints.

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[www.hydraraptor.blogspot.com]

Just so I understand - it's clicking so strangely because the extruder controller isn't a real stepper driver?

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Tony Buser http://tonybuser.com * http://reprap.org/wiki/User:Tbuser#Projects

No it whistles because it isn't a stepper driver. It clicks because that is what steppers do unless you micro step them. The RepRap stepper drivers don't do micro stepping so I would expect the same clicking or a rasping buzzing sound if going faster.

If you listen to this video you can hear Mendel makes a god awful noise when driven with the RepRap electronics. [www.youtube.com]. I think it's a bit exaggerated by the placing of the microphone.

Now compare that to the sound of my Mendel which uses micro stepping drivers. [www.youtube.com]. The axis drivers are actually RepRap V3 stepper drivers that Zach designed but hasn't put into production for some reason. The extruder controller is my own design with x8 micro stepping. Basically the sounds are 8 times higher in frequency but also 8 times lower in amplitude, so a lot less harsh and in fact quite musical.

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[www.hydraraptor.blogspot.com]

I see. Thanks for explaining the difference. Last night I decided to try some different firmware (mainly because the FiveD was having a hard time maintaining a steady temperature). So I ended up loading the MakerBot firmware (not sure what the proper name is - MakerBot? Sanguino? Gen3? v2?) from [github.com] after I realized the version in the RepRap svn is really old compared to this. Using the ArduinoSlaveExtruder firmware (the v2 branch doesn't support stepper motors yet, but the v2 motherboard firmware does work with the 1.8 ArduinoSlaveExtruder firmware) - the extruder stepper is a LOT quieter, particularly when stopped. It still clicks when turning, but now I know that's to be expected. Here's what it sounds like: [www.youtube.com]

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Tony Buser http://tonybuser.com * http://reprap.org/wiki/User:Tbuser#Projects

So anyway, I went back to the RepRap firmware and figured out how to interface a pololu with the reprap motherboard and firmware to just control the extruder motor. It's a pretty huge improvement! Almost totally silent and runs a lot cooler. I blogged about what I did here: [tonybuser.com]

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Tony Buser http://tonybuser.com * http://reprap.org/wiki/User:Tbuser#Projects