Rods keep detaching all of a sudden

I’ve been printing for quite a while now, with 0 issues.

Suddenly, today, the rods started detaching, and i can’t for the life of me figure out why.
Yes, the balls are oiled. Yes, the rods are oiled. thing is, i can remove a rod by just very lightly tugging it - i don’t remember the magnets being this weak.

Very weird.

The only idea i’ve got for a potential cause is that i’ve been printing some harder to extrude filament lately, at lower temps - maybe the force of the coiled bowden tube keeps tugging on the head during fast retracts and reprimes because of higher than usual extrusion forces?

Edit: Forgot to add… this is happening mid-print, and i’ve got a pretty decent Z-hop enabled, so it’s not nozzle dragging or snagging on something.

Hi @orcinus,
You can try:

  1. Check the belt tension.
  2. Reduce the travel speed, because a delta does a limited number of straight movements per second, I think a fast moving could scratch on your print if z-hop isn’t high enough.
  3. Try the sleds by @Dr_Vegetable, @SusisStrolch or @Psycho
  4. Check the magnetic balls, mine got damaged surfaces after some time but I found same size ones in lokal retail store.

Thanks! Already checked 1; 2 never changed (printing same objects / files i was printing before, at the same speeds and acceleration); that leaves 4, and if everything else fails, 3.

To add insult to injury, one of the thermistor wires detached while i was cleaning the hotend from a really bad clog. I pulled it out, and it turns out the thermistor is soldered to the wires, right there, in the block. No wonder it detached, that should be crimped, or soldered outside of the block. I’ve replaced it with a bead-type epcos 10k that i’ve wrapped in tin foil and fire cemented in place, with PTFE tubes serving as the insulation for the leads.

I took everything apart while checking the belts, cups and rods, cleaned and polished everything up, and relubed with sewing machine oil… So far so god, at least i got a calibration cube out fine :slight_smile:

I’ll check the balls and print out some linear bearing sleds over the weekend.