Delta Printer Motor Setup

Hi!

I have built a Delta Printer, but am now trying to get it working... I have downloaded the Marlin firmware RichCattell, which is setup for the Delta Printer. However, now I have to calibrate, or at least get the motors working.

I try using G28, which should home the axes. Indeed, all axes move up to the end stops. However, clicking in the Repertier Host the X+1, Y+1 or Z+1 all moves the extruder to the same direction (up). Clicking X-1, Y-1 also moves up, while Z-1 does nothing.

I have looked in the configuration, but did not find any real settings that would explain such behaviour. These are the settings for the motors:

#define DEFAULT_AXIS_STEPS_PER_UNIT   {160, 160, 160, 439.5}
#define DEFAULT_MAX_FEEDRATE          {50, 50, 50, 50}    // (mm/sec)
#define DEFAULT_MAX_ACCELERATION      {200,200,200,200}    // 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          200    // X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION  200   // X, Y, Z and E max acceleration in mm/s^2 for retracts

// Offset of the extruders (uncomment if using more than one and relying on firmware to position when changing).
// The offset has to be X=0, Y=0 for the extruder 0 hotend (default extruder).
// For the other hotends it is their distance from the extruder 0 hotend.
// #define EXTRUDER_OFFSET_X {0.0, 20.00} // (in mm) for each extruder, offset of the hotend on the X axis
// #define EXTRUDER_OFFSET_Y {0.0, 5.00}  // (in mm) for each extruder, offset of the hotend on the Y axis

// The speed change that does not require acceleration (i.e. the software might assume it can be done instantaneously)
#define DEFAULT_XYJERK                5.0    // (mm/sec)
#define DEFAULT_ZJERK                 5.0    // (mm/sec)
#define DEFAULT_EJERK                 5.0    // (mm/sec)

Anybody an idea what might cause this?

Thanks!
Steph

I think that my problem has to do that I did not do a homing yet.

Now I am trying to get that sorted out... When I do a homing (G28), all my axes move up. However, when I click my End Stops (to simulate a homing hit), nothing happens except for one of my end stops. For that end stop, the movement of all axes stops. Once I click again, the movement starts again going up.

This seems to me not the correct homing sequence. I would expect the homing to go up until it hits the end stop and then go back down a bit to go up very slowly until it hits the end stop again.

Is there any setting that might mess up with the homing sequence?

Thanks!

Hey!

I found what was going wrong!

It appeared that I had not one but two faulty Stepper Motor Drivers. After swapping them, all worked fine and I could start with the calibration after proper homing!

Next time, I'll be sure to test these drivers first :-)

How did you determine the drivers were bad? Is it possible they were not passing enough current because the pot was set to low?

Thanks.

Hey Kurzaa

I forgot to update this post to the latest situation. In the end, I went down the wrong path... The drivers most likely are not faulty, as they now function quite well, even if I swap them again. The thing that most likely resulted in the odd behavior, is that the end stops were connected to the wrong pins. I connected the MIN instead of the MAX. That sure didn't help :-)

Now things are moving as expected.

As for the drive pots, I manually set these and did not have much trouble finding a good spot. The delta printer has quite light carriages, which might explain why the drivers do not have to pass much current to accommodate their motors.

Thanks for the question!