Z-homing causes filament to unspool and jam

Hey :slight_smile:

After 2 weeks of using my new A1 Mini, I’m very happy.

The only problem I have so far is this :

  • At print start, it runs a calibration and homing, which moves the print head all the way to the top.
  • This causes the head to unspool about half a turn of filament from the spool.
  • Then the head moves back down, but the spool doesn’t rewind itself, so a loose filament loop remains.
  • Eventually this free loop tilts on the side, and then this happens at print time :

As you can see, while the extruders grabs some filament during print, since the free loop is not on the spool anymore, it will just create this filament jam, until the printer stops in error mode saying filament is blocked.


The only solution so far is to make sure to REWIND myself the spool after homing, but it means I can no longer launch a print without being just next to the printer :frowning:

Anyone with the same issue ?

I don’t have a mini, but with my a1, I’ve had to mount the spool to the wall and reroute the tube to feed a little better. I had trouble with full spools unwinding like that but it was the fault of the spool (IMO) in my case, as they were those 1.1kg overstuffed ones. The slightest amount of rewind on those turns it into a wild spaghetti tangle. Your spool doesn’t look so full, but that feed angle does look troublesome if it doesn’t rewind. (The ams rewinds for you)

I think you need like 5-10cm more noodle length between the inlet and the spool to take some slack.

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At the end, after several prints, the spool has lost some weight, and now the sides of the spool are high enough to avoid this problem. But indeed, it’s persisent with new spool, unless like you say I avoid using the official spool holder which is too close to the tube