<p>I am encountering a problem with this ID3 printer using ABS -- at some point during the print the print head displaces on the y-axis by 2-3 centimeters. I cannot pinpoint how or why it is doing this. It has displaced in the positive Y direction and in the negative Y direction on separate runs of the same piece (which is just a poker chip I found on Thingiverse). </p>

<p>Is this a software issue (Simplify3D) or a hardware issue? Can anybody suggest a fix?</p>

<p>See the following photos:</p>

<p><a href="https://i.stack.imgur.com/b9Kyv.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/b9Kyv.jpg" alt="3D print exhibiting positive Y displacement mid-print"></a></p>

<p><a href="https://i.stack.imgur.com/1yH40.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1yH40.jpg" alt="Close up of 3D print exhibiting positive Y displacement mid-print"></a></p>

It seems unlikely this is a software or G-code issue, instead it appears your Y-motor is occasionally missing some steps. There are two possible causes for this:
The current limit for the stepper driver is set too low, limiting the amount of torque the motor can generate. When the printhead encounters some resistance (for instance due to running into a blob on your model) the motor skips steps, resulting in a displaced model.
The current limit for the stepper driver is set too high. The stepper driver will overheat and thermal protection will shut it down temporarily. Some steps are lost while it is shut down.
There are various ways to calculate the ideal current for a motor and set it using a multimeter, but a simpler approach is to turn it way down, and then slowly turn it up. Turn it up just beyond the point where the axis moves reliably.