I hope someone has some ideas or solid info that can help me out.

3D Printing
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I hope someone has some ideas or solid info that can help me out. I’m having a very consistent X/Y drift issue that I do not believe is due to mechanical factors or thermal shutdown.

I’ve built a fairly large machine inspired by the Ultimaker/Herculien. Because of its size and the speeds I desire, I am using Nema 23 motors for the X and Y. Those motors are driven by two stand alone Gecko 213V drives (prior to those I was using the Sain Smart TB6600 based drives). I’m piggy backing the x/y signals from the Azteeg X3 Pro to them with some jumpers.

When I first built the machine I had a problem with every layer shifting by a consistent amount in the SW direction of the build plate. However the shifting problem disappeared and I unfortunately never figured out exactly what caused it. As I continued tuning the machine the problem appeared again. I just switched over to the Gecko drives today and they unfortunately did not resolve the problem. After a horrible run this morning, that was shifting somewhat randomly, the direction has now changed to the NE of the build plate.

I have tried Repetier 0.92 and newest Marlin. I’m currently running Marlin now. I have tried stepper delays and Toshiba Stepper configuration, different accelerations/jerk settings and I cannot figure out the problem. I’ve also ruled out false end stop triggering by making sure end stops are only for homing. The problem is not dependent on a specific slicer either.

I just ran a cube with 0/90 deg infill and no perimeters. I did not let it complete but it seems to be straight. The same cube with 45 deg infill and no perimeters is shifting very badly in several directions, seemingly related to the direction in which the previous/recent layer(s) were printed.

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The step signals coming from the common 3D printer controller boards are very, very short. Each pulse is about 1.9 microseconds. Most stepper drivers require a longer signal than that, the gecko drivers want a 4 microsecond pulse minimum I think.

I’m not entirely sure how you’d go about changing that behavior, or how much work it would be, but that would probably explain a lot of the problem you’re seeing. If you need higher power capable drivers that can handle the short pulses, though, I do know massmind’s THB6064AH drivers will work with the short pulses and push up to 4A sustained. Their site looks super janky, but the product seems good, and has shown up in a number of interesting builds I’ve come across.

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@Stephen_Baird thanks for the input. I was hoping that the Toshiba configuration in Marlin or the stepper high delay in repetier would adjust that. I couldn’t find any documentation to confirm or deny that though. I’ll check out those drivers too.

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The G213V requires 1us on and 2us off. http://www.geckodrive.com/g213v.html I’m going to dig around some to see if I can add some delays to the code that generates the pulses as the Gecko drives are VERY nice and quiet.

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1us on should be within the standard pulse length for Marlin or Repetier. But could you have the step logic inverted? That will make every run of motion in a particular direction be one microstep short. Which can cause consistent drifts that depend on the geometry being printed.

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@Ryan_Carlyle it is entirely possible. I will run some tests today.