z axis isnt working

so i just built my first 3d printer( reprapguru prusa i3) however on the final set up the x and y axis can be moved maually in repetier 1.5.3 however my z axis refuses to move. i followed all the instructions on their G drive for the build and the setup. i have swapped the z stepper driver and the y stepper driver and y still worked but z still didnt move i pluged the z motor wires into the y axis connector one at a time and was able to move the z axis motors that way i tried turning up the potentiometer on the step driver and still got nothing however if i shut everything down the first time i try to home the z axis i hear a click that sounds like its coming from the motor im not really sure what else to try at this point. I have also manually ran the screws up and down for the z motors and they dont seem to be binding im pretty sure it has something to do with my setup that i installed everything i used for the board setup was pulled from [goo.gl] the only difference is that repetier forced an update to beyond what is called out in the build manual.

Bump

Is your Z endstop working correctly? Have you tested it with the M119 command?

Are your Z motors connected in parallel or in series?

Have you tried with just one single Z-motor connected to the Z-driver? Does it move? If not does it move with the cable from the X or Y motor?

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my objects

I hope you have solved this by now, but ill document my problems here so someone else can use my solutions later. I had similar problems on a prusa i3 i just built from a kit. I had a couple problems too.

1) The connectors on the motors were different than specified by the manufactures circuit diagram. I had to switch the wires so that they matched what the circuit diagram actually wanted.

2) The manufacturer's circuit diagram called for the motors in series, but everything I saw on here said do them in parallel.

3) My feed rate was by default set to 9999. This was freaking out the motors and drivers. Changing the feed rate in the firmware to a much more reasonable 3 finally fixed the problem.

Quote
AudaciousTuddle
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2) The manufacturer's circuit diagram called for the motors in series, but everything I saw on here said do them in parallel.

Except when using low current/high voltage motors, series connection works better than parallel. The reason most people use parallel is because the RAMPS board makes it easy.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Did not know you could do series. That would indeed need a higher voltage from the stepper.

Typical motors used in RepRaps are rated for between 1.3 and 1.7A at around 3V. The plug-in drivers on a RAMPS are only good for about 1A, or a little more for DRV8825-based drivers or the T3P3 Ice Blue drivers. Drivers embedded in electronics boards can generally handle somewhat more current, because they are better cooled by the PCB. These driver chips are designed to be cooled by the PCB and those stick-on heatsinks are virtually useless - perhaps worse than useless, because they may reduce airflow around the PCB.

So if you connect 2 if these typical motors in series, you can drive them at 50% to 80% of their rated current, and they will only drop between 1.5 and 3V each, or 3V to 6V in total, well below the typical 12V supply voltage. The use of 2 motors in series and the extra voltage needed will limit the maximum speed compared to a single motors, but high speed isn't usually needed on the Z axis anyway despite the gearing. OTOH if you connect 2 motors in parallel, the current will be shared between them, so you will only be running each motor at 25% to 40% of its rated current, and the torque will be correspondingly reduced.

I have heard that some 3D printer kits are supplied with 12V 0.4A motors. Such motors are a very poor match for the stepper drivers. However, if you do have a kit with those motors, then connecting them in parallel would work better than in series.

Edited 1 time(s). Last edit at 10/01/2015 01:45PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].