Taz 5 Stringy Print

On the Taz 5 I’m printing on, the most recent print came out very stringy with the layers not adhering well to each other. See the attached image.
20181101_090322[1].jpg

What type of filament?

Try a lower extrusion temp and cooling if its not ABS. You can also try increasing the retraction distance (increments of .1) and making sure its retracting across open spaces.

I’m working on the same printer.

The filament is PETG, at 240 extruder and 50 bed. I’ve attached how a print looks with PLA at default PLA settings. My first thought was flow (it looks like it’s putting out too much material, squeezing it out the sides), but at least with PETG decreasing that doesn’t help any.

From the extreme “wobble” in the z-axis, my first thought would be to check the printer for loose mounting brackets – start with checking the nozzle/hot-end is secure in the plastic to which it is bolted, then check the print-head itself and make sure it can’t wobble from side to side (in any direction). Check the x-axis rods as well, make sure they aren’t loose in their mountings on either side. It’s worth wiggling the z-axis lead screws and rods as well, make sure they’re tight. Finally, check the bed – see if it wobbles from side to side (in any direction).

I’d like to be more specific on which might be loose, but the prints look so bad the problem could be anywhere. But I doubt it’s just an extrusion issue with such extremely poor z-axis surfaces.

Definitely a lot more going on there than just stringiness…

A mwester said, it looks like something is loose. It looks pretty extreme for z-wobble, but not ruling out.

Check:

  • Toolhead secured to x-carriage
  • Grub screws tight on the lead screw couplers
  • GT belts on X and Y
  • TIghten x-carriage guides and check GT-belt
  • Y-axis GT belt assembly under the aluminum bed
  • Overall tightness of frame

Things come loose over time… I’m guessing that’s whats going on here.

I’ve tightened every bolt I can get to on the printer, just a few were loose, and turned the speed to 15mm/s for everything just for kicks, but I’m still getting the same result.

Well, it doesn’t have to be a bolt. I had trouble on my original mini with print quality one day – turns out that the printed bracket holding the left-side of the x-axis rods had cracked at some point (layer separation). All the screws were tight, but the entire head assembly wobbled back and forth badly every time the head was at the left-hand side of the print…

The key is to wiggle the bed (it moves) and the head (it moves), and look to see if whatever is moving seems loose or sloppy. I wish I could give you some specs (e.g. the head should not move more than millimeters in the horizontal plane when a force of is applied… etc etc), but AFAIK there are no specs of that nature available. So, just move it around – it’ll have some jiggle (small), and flex a bit beyond that. The jiggle should be minuscule, the flex depends on how much pressure you apply, but if a light pressure moves the head or bed around, then look to see why – perhaps a bushing is worn, or you have a cracked bearing, etc.