Help needed! Problems with repetier setup

Hi Guys,

Just trying to configure my diy tech shop printer kit and am having a few issues and would love some help!

All three endstops are functioning and the X and Y axis home well, however the Z axis doesn't home. It moves up and down happily in manual mode, however when I try to home it the motors vibrate. With a little from me, they move downwards and stop when they hit the Z endstop, but won’t do it themselves. Would anyone know why the axis moves down fine, but only gives me this problem when I try to home?

Also, despite putting 300mm for the X and Y axis in the printer configuration settings, I can only get 250mm before the X and Y aren't allowed to go any further. Any feedback would be much appreciated.

Thanks in advance,

Jeremy.

I am a newb, but the first thing I would check is running an M119 (?) command which should give you the current state of your end-stops. It is possible that the Z end-stop is configured incorrectly.

When I had similar issues with the motors getting power but not moving, I believe it was a wiring issue. My end-connections on the terminals sucked. Bought a crimper, re-did them all, and everything worked fine.

However it might also be a voltage issue on your stepper drivers. Unplug the power, next your motors, and then plug your Z-motor into the drivers for you X or Y motor. Use the manual control to see if the motor is working correctly. If so, try plugging another motor (after disconnecting power) into the Z-stepper drivers and ensure that they can correctly move your motor. If not, you probably need to increase the voltage of your Z-driver.

As for the bed size, I believe Repeiter only uses the bed size for visualizing prints and ensuring that the files will fit on the bed. The actual dimensions of your printer are set in the firmware. So you will need to edit and recompile the firmware (I think).

Hi Kurzaa,

Thanks for the hints! Will try them out tomorrow and report back.

First off, bed size problem solved, Thanks for the tips!

I have tried resoldering the wires without much success. I have also tried playing with everything endstop related in the configuration file. I'm in the process of trying out the next set of fixes and have a couple of questions...

The machine has 2 z motors and 1 motor for every other axis. Would I need to change the config to divert current from 2 other axis into this one?

What is the best way to run an M119 command for z in repetier?

How can I change the voltage going to the drivers?

A ton of Thanks in advance!

I had a similar problem. It sounds like Repetier is trying to drive the Z axis too fast for your steppers when homing, but not when doing manual moves.

Here are 3 things to check:

1. Repetier's Printer Settings:
Z-Axis Feed Rate (mm/min)

2. In your firmware's (e.g. Marlin) Configuration.h file:
#define HOMING_FEEDRATE {50*60, 50*60, 5*60, 0} // set the homing speeds (mm/min)

3. In your firmware's (e.g. Marlin) Configuration.h file:
#define DEFAULT_MAX_FEEDRATE {3000, 3000, 300, 20} // (mm/sec)

I am guessing that the Z-Axis Feed Rate in Repetier and/or the DEFAULT_MAX_FEEDRATE in your firmware is lower than the Homing_Feedrate. So on manual moves the Z-axis is fine, but when homing it tries to move too fast, overdriving your Z stepper motors. Lower the Z-axis Homing_Feedrate (the 3rd number, 5*60 in the example above) to match (or be lower if you need more precision when homing) the DEFAULT_MAX_FEEDRATE values (careful, these are in mm/sec) or Repetier's Z-Axis Feed Rate.

Hi Robert,

Thanks for the reply and Sorry about the delayed response. I will try these out and get back to the forum with my results.

All the best,
Jeremy.

Solved!

This one did indeed relate to a problem with the homing feedrate. When it is turned waaaay down it works.

Thanks so much!!

Jeremy.