Park, home, and Y axis skip problems after E3D install (Page 3 of 5)

I hada similar problem a while back. I ended up changing the Y stepper to a more uprated version, zero problems since. They are pretty cheap, maybe that's the go?

Just for completeness, I'm recording my observations here.  I did a very slow, patient, careful bed leveling, not allowing myself any shortcuts from having done this so many times.  It seems that my print bed is now slightly off flat; the center is a tiny bit lower than the edges.  I imagine if I put some water on it and waited long enough it would pool in the center.

This was brought up before, I asked about it, and got no directions for how to do this.  I've Googled for it and can't figure out what procedure is being referred to.  Is this as simple as taking the connections from X and Y at the circuit board and swapping them, then printing?  (Which would, if I am following this correctly, make my print end up coming out rotated 90 degrees?)  Or do I have to redo the potentiometer adjustments to reverse the X and Y voltages (since their ideal values aren't the same)?

Right, that's what I was afraid of.  These are the chips that are soldered down onto a circuit board, just near the potentiometers, as shown in the pictures here?

Not that. You don't have to unsolder anything. He is talking about the entire piece like I showed above. The circuit board and all is the stepper motor driver assembly. That was Hazer just misspeaking. I am positive he didn't mean the chip itself.

Fair enough, and I wouldn't even call that a misspeak; when adding memory to a computer, people always say "chip" when they mean the whole board the chips are on, so it's just an ambiguous common terminology.  I didn't even realize those were on four separate daughterboards, honestly.  (I've had fans covering the board since only a few weeks in from when I was able to print, so I don't stare at it much.)  This is something I could do, though the thought of burning a couple of hours doing those pot adjustments is not one I relish, and that it's just a coincidence it went from always to never while I was doing the E3D install and didn't even touch it is highly discouraging.

To do it by sound, you set the motors to move really slowly when doing manual moves by changing the Travel Feed Rate in Printer Settings.    Then when you move the axis you can hear the motor pulsing.  At slow speeds the steps are taken slowly enough that you can hear the rhythm.  2n2r5 is talking about adjusting the Vref until you hear the pattern smooth out.  The motor can't provide as much torque on microsteps as it does on full steps.  Sometimes microsteps get skipped until it gets to the next full step, and having the current too high or low gets things out of sync a little, and microsteps get skipped.   This will cause more of a pulsing, clicking sound rather than a smooth tone.  This blog post has a video example of a motor running with skipped microsteps - http://hydraraptor.blogspot.com/2012/04/stepstuck.html.

For X and Y, I would stick to the multimeter reading, though I don't know that it is vital to get it right to 3 decimal places.   The sound method is more for tuning the extruder motor to eliminate moire.  In that case you want it as correct as possible, and the right Vref for smooth extrusion might not be exactly the voltage specified.

So for Y skip, the problem might be:

the axis is too hard to move
     misalignment, or too much belt tension
     nozzle snagging on plastic sticking up from over extrusion, overhanging perimeters curling up, stray threads from failed bridging.
the motor doesn't have enough torque -
     a problem with the stepper driver (swap drivers and see if the problem moves to the other axis)
     a problem with the motor
the stepper is experiencing thermal shutdown from overheating- unlikely since you have a fan

As for something about the E3D causing the problem, the only reasons I can think of is over extrusion from the new hot end not being calibrated, or bridges.  I'm finding that my E3D is really bad at bridging, but that might be because I'm printing hotter.  The settings that worked on the J-Head don't work for the E3D, so if I have a bridged area I am more likely to get loose threads and blobs sticking up because the ends didn't get stuck down at the other side of the bridge. 

I don't know that the different requirements of the E3D heater would affect the stepper drivers, but if it did, switching them between X and Y would point to that problem.

Second successful print, again something small enough to stay in the center of the print bed and not get near where it bows upwards.  Now trying a third.

(The bow upwards is very slight -- maybe a half-millimeter at most -- but it's enough to make z-axis calibrations so if they work at the center, the head bumps at the front and back, and if it's calibrated at front and back, nothing sticks at center.)

The things I just printed are the two-color slides that slide into the previously printed frame.

In fact, the frame is what I've been failing to print all this time since before the E3D.

Maybe two corners lets the glass wobble a bit.  Try 3, but not 4.

After four successful smaller-part prints, I'm going to start stretching.  I'm going to print one of the frames like above, but I'm rotating it to print with its longer axis running left-right (X) instead of front-back (Y) in the printer, since the "bowing" is more to the back and front than side to side.  If that works, I'll try it running front-back (the default).  That way I can see if the grease made more of a difference, or the bowing.  For the duration of this testing, I'll leave it to two clips as usual -- just to not change too many things at once, so I can identify which ones are making the difference.  I'll try the more-clips approach after those tests.

This is exciting, having some things print successfully for the first time in so long.

It certainly felt smooth and easy to me, but if my printer's always had a little trouble there, I might not know just how easy it is supposed to be.  I know someone who had this problem with a doctor; the doctor asked if he had frequent heartburn and he said no, when he had it several times a week, because that seemed normal to him, he'd always had that, and others in his family had had it worse, but to the doctor that was definitely 'frequent'.

Says either the bed or the rails are bowed. My money's on the latter.

Turns out that skip might be a false alarm.  I generally watch my prints like a hawk, but coincidentally during that one I had to step away for a bit due to a dog-related emergency, and while that's usually fine, it seems that the filament on the spool tangled somewhat.  I didn't discover this until I was setting it back up for another try.

Doing the same print from the same slice, only with three clips instead of two on the glass bed.  It's on layer 9 and no skipping.  So it's possible that that previous one would have worked if it had gotten my usual level of attention, or it's possible that the extra clip helps.

I don't know if I'd be able to tell if there was a skip if it weren't extruding, unless I happened to be looking right at the print head the instant it skipped and maybe not even then, if it were a small enough skip.