1 Topic by karltinsly

  • karltinsly
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Topic: X axis zero point changing

I have a DaVinci 1.0 flashed with Repetier and updated with an E3D hot end and borosilicate glass, among other things. It has been printing very well for months - in fact, I recently finished printing all the parts for my mostly printed CNC with no problems at all. Today I kicked off a print, and had to kill it or short while later, because it was missing steps on the x axis - layers were printing offset from each other from right to left. I tried printing several different parts, even slowed the multiplier down to 90, but still it would start dropping steps within the first couple of layers.

So this evening I was just keying in some gcode commands, looking for anything that could be causing the problem, and I observed this behavior for each of the following commands:

G1 X150 Y150 - head moves to forward left corner
G1 Y20 - head moves straight back to rear left corner
G1 X0 Y150 - head starts to move to forward right corner, but ends up forward center

From this point on, until the x axis is parked again, the machine thinks that x0 is in the center.

If I park the x axis, and issue G1 commands to move the head back and forth on the x axis, it is fine, and returns to the correct x0. But if I send it to x150 y20 or thereabouts, and then try x0 y150, the x0 gets stuck in the middle again.

There are no unusual noises or anything when this happens. Any idea why this is happening?

2 Reply by carl_m1968

  • carl_m1968
  • carl_m1968
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  • From: Far North almost not Dallas
  • Registered: 2014-10-17
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Re: X axis zero point changing

karltinsly wrote:

I have a DaVinci 1.0 flashed with Repetier and updated with an E3D hot end and borosilicate glass, among other things. It has been printing very well for months - in fact, I recently finished printing all the parts for my mostly printed CNC with no problems at all. Today I kicked off a print, and had to kill it or short while later, because it was missing steps on the x axis - layers were printing offset from each other from right to left. I tried printing several different parts, even slowed the multiplier down to 90, but still it would start dropping steps within the first couple of layers.

So this evening I was just keying in some gcode commands, looking for anything that could be causing the problem, and I observed this behavior for each of the following commands:

G1 X150 Y150 - head moves to forward left corner
G1 Y20 - head moves straight back to rear left corner
G1 X0 Y150 - head starts to move to forward right corner, but ends up forward center

From this point on, until the x axis is parked again, the machine thinks that x0 is in the center.

If I park the x axis, and issue G1 commands to move the head back and forth on the x axis, it is fine, and returns to the correct x0. But if I send it to x150 y20 or thereabouts, and then try x0 y150, the x0 gets stuck in the middle again.

There are no unusual noises or anything when this happens. Any idea why this is happening?

You most likely have a loose or damaged harness on the X endstop. The logic looks for a low on the endstop to tell it when the axis is home. If at any time there is a break in the connection while moving it will see that as a low and mark that point as the new home position.

Printing since 2009 and still love it!
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3 Reply by karltinsly

  • karltinsly
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Re: X axis zero point changing

That makes sense. I'll take a closer look at the harness and endstop. Thanks!

4 Reply by karltinsly

  • karltinsly
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Re: X axis zero point changing

I spent hours opening up the wiring harness and inspecting various wires. I could definitely cause the problem by moving and wiggling the wires, but could never isolate a single wire as the problem, much less find a suspect spot on any of them. Eventually I swapped the x axis endstop with the cover sensor (which I disabled long ago), and the problem has gone away. I put everything back together, and it's been printing happily for the last 6 hours, so it looks like the problem was the endstop itself.

Thanks again for the help!