Friday, 25 December 2015

Maybe I should give this up and become a sailor

Digging into the X-axis thing some more. Possible explanation include:

  • Need oiling - just reoiled now with sewing machine oil
  • Rough rods - were initially smoothened with iron sponge, but it may not have been enough.
  • Bumping the previous layer - ought to be the same slip for a given part, which is not the case.
  • Motor overheating - they're cool on the outside, so probably not that.
  • Loose bed - that would show up in the Y direction.
  • Loose belt - they strum somewhat, as can be heard in the video below, but I don't know what they should sound like.
  • Slipping belt?
  • Back-pull from the print?
  • Gremlins?
Tried increasing layer height to .5/.72 mm. Clearly can't be more than that, since that's my nozzle diameter. Doing the wire holder again, this is clearly not a good idea, it looks like cable loosely tossed together. Reducing to .35/.6mm.

When trying this print, it did the corner print again. When trying to center after homing, the X-axis didn't move at all. So I did some tests noting where the extrude rhead was and then running 10cm back and forth repeatedly. In the beginning, there was some difference at the end, but after a few more runs, it wasn't noticably skewed.

I strummed the belt, and didn't quite like the sound of the X:

So I tightened it about one full turn of the screw. Then I noticed the belt was rather disaligned with the pulley and re-aligned that:

Once printing, it comes back out somewhat almost immediately, though. After increasing tension, it comes out even more, almost coming off.

After leaving the machine standing for a while, it seems to lose contact with the thermistors, and the readings just stay there. Disconnecting and re-connecting fixes it, but it's a bit annoying.

After tightening the X belt, I got a much better print. No skew in X and at most a little bit in Y. It still looks very sloppy, though. I've tried to look at whether the nozzle is too high, so the thread can fall to the side, but it's difficult to tell.

Here are the last two prints, both after tightening. You can clearly see the coiled-rope look of it, and on the last (on the right) there's notable X-axis skew again. Sigh.

1 comment:

  1. Given the tension causing it to ride off the drive pulley more quickly, have you checked that your motor shaft is perpendicular to the X smooth rods? I wonder if they're a little loose in the holes.

    Also, does it require a change in Z before it has problems? If you print a big single layer square, does it have an X offset at some point?