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I have been searching around the internet for the last 3 days trying to figure this out. My Z axis motors for a pursa-i3 3d printer are not working correctly. I have marlin firmware and using repetier host. I send a command to move the z axis and I get it to move, however I if I send the same command again the motors will sometimes spin the other way. feel like They almost randomly choose which direction they turn.

As I said I have been trouble shooting this for a while now. What I am suspecting is the firmware feedrates and acceleration or some setting is not correct.

Here is my code:

//// MOVEMENT SETTINGS #define NUM_AXIS 4 // The axis order in all axis related arrays is X, Y, Z, E #define HOMING_FEEDRATE {50*60, 50*60, 2*60, 0} // set the homing speeds (mm/min) #define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,4000,590} #define DEFAULT_MAX_FEEDRATE {300, 300, 3, 45} // (mm/sec) #define DEFAULT_MAX_ACCELERATION {1000,1000,50,500} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for Skeinforge 40+, for older versions raise them a lot. #define DEFAULT_ACCELERATION 1000 // X, Y, Z and E max acceleration in mm/s^2 for printing moves #define DEFAULT_RETRACT_ACCELERATION 1000 // X, Y, Z and E max acceleration in mm/s^2 for retracts #define DEFAULT_XYJERK 10 // (mm/sec) #define DEFAULT_ZJERK 0.3 // (mm/sec) #define DEFAULT_EJERK 5.0 // (mm/sec) 

I tried swapping the drivers around and the motors will work perfectly on another axis so I don't suspect it to be a driver issue. I have been turning the pots ontop of the drivers to make them work but can't make them to go the same direction i want them to.

I've checked the wires and I almost sure they are wired up correctly. (could be wrong but have checked it over with a multimeter.)

I am new to this and it's my first time building one of these would appreciate any help I can get and and maybe I have over looked something I have tested. Just really want the axis to move in the direction That I say it to move in.

More details about my setup is: A Robocraze 3D Printer Controller Board RAMPS 1.4 using A4988 stepper motors drivers and my motors are the nema 17 stepper motors. I currently have the two z axis motors wired in parallel but have tried before using series, however the problem of being unable to control the direction of the Z motors still arises (can easily switch back to series).

currently trying with no load just to get the motors turn in the correct direction when I send a G-code command. I am using Repetier host on ubuntu 14.04.5.

I have also check the endstops and they are working perfectly, so they ain't a problem (I don't think :p)

Thank you, Bobby

1 Answer 1

So after 5 days of trouble shooting, Bob-the-Kuhn over on the marlin github forum solved it for, anyone else who faces the same issue can head over to github for my solutions.


Conversation from link:

Bob-the-Kun: Problem does not follow the driver. Problem does not follow the steppers.

I'm thinking that the Z socket has a problem. Sounds like an open/poor contact.

Try bending the DIRECTION lead on the Z driver a little and see if the problem disappears. It's one of the corner pins. Sometimes it's called DIR. If your driver's pins aren't labeled then bend all four corner pins a little.

Another option is to move the Z function to the E1 socket. Replace your pins_RAMPS.h file with this one. pins_RAMPS.zip

FYI - if this really is a hardware problem then it's the second RAMPS hardware problem within a week. Most unusual.

Post reply:

Yes the socket I am now assuming is just broken (not sure what exactly but possibly one of the connections), After using for pins_RAMPS file and changed the motors back to series and connected to the E1 slot I successful got the printer to work!!! Thank you very much Z axis is working as I would expect! I am now calibrating the printer as it definitely needs it.