I have been printing very square cases for a wr703n project, and they have been leaning toward the front of the printer. I have had binding issues before and usually you hear the stepper missing the turn. But not so in this case.
During my hunt for the problem, I’ve grease all the bearings, realigned the front and rear Y idlers, broken both rear bar clamps, and ran off about 6 test prints; All with 1.5mm width walls. Only during the last print did I notice that both of my Z axis smooth rods where angled forward about the same angle as the prints… I have put a few kilos of bot PLA and ABS through it and not once did a pickup on it. I’m guessing I just skipped the step during the build where you align them with a weighted string.
Anyway, here’s a before and after comparison: Green is before, red is after.
When printing the ‘after’ object, I did notice that the first layer (PLA) was cleaner and more even.