Printing TPU Problems

Artisan (3-in-1)
1

Using TPU (black) with the .4mm nozzle consistently jams between the drive gears and the top of the hot end. Also, the extrusion is too narrow.

I believe the nozzle size is too small for the flow rate so the filament backs up between the drive gears and hot end. I have tried adjusting the flow rate, but that has not helped. I really want a wider extrusion, not a smaller one.

So would a larger nozzle help with both problems?

2

According to official Snapmaker pages TPU needs to be shore hardness 90 or above. Is your TPU in that regime?

3

The item I’m printing needs to be softer than Shore90, I’m using Shore 65A.

4

I printed with Filaflex Shore 82A without problems using slow speeds, a 0.6mm nozzle and a 3d printed connector, which closes the gap between hotend and exturder. The connector has to be placed on the hot end filament intake before the hot swap nozzle is inserted into the dual extruder.
https://www.printables.com/de/model/993227-snapmaker-dual-exturder-tube-connector-for-flexibl

5

Great, thanks for sharing, good idea!

6

I had the same problem as you where the TPU material would get jammed in the gears. Happened several times. I slowed the speed down to around 25 to 30. I also turned retraction off. I think this was the fix. I’m also using a 4mm nozzle.

Stay persistent!
Mike

7

@Lew @MikeH
Yes, you can find the full specifications for all machines here: https://support.snapmaker.com/hc/en-us/articles/7319352864407-Comparison-Among-Snapmaker-2-0-Artisan-J1s-and-Ray

The Snapmaker Artisan and J1/J1s support printing TPU with a hardness of 90 or above.

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8

I’m using OVERTURE TPU Filament 1.75mm Flexible Roll, 95A Soft 3D Printer Filament, 1kg Spool (2.2 lbs), Fit Most FDM Printer (TPU Black), and the filament is STILL getting tangled up in the extruder gears.

9

I’ve been fighting repeated Polymaker TPU 95a jams on my Artisan for weeks. The symptom was very consistent, described as above and below:

  • First 30–60 minutes: prints fine, no obvious issues.

  • After about an hour: filament starts getting snagged just before the hot end, then bunches up in the extruder head between the gears and hot end, bypassing the nozzle entirely.

I tried all the usual suspects:

  • Reduced retraction from 2.5 mm down to 1.5 mm, then 0.5 mm, then fully disabled it in Orca Slicer.

  • Slowed print speeds to 10 mm/s (1.5mm3/s).

  • Checked and cleaned the drive gears,filament tension (unspooled a ton of filament to make sure tension was as low as possible).

  • Verified smooth manual extrusion and swapped hot ends.

Nothing reliably fixed it on long prints. Short tests would succeed, but anything over ~45–60 minutes would eventually jam in the same way.

->What finally worked<-

The breakthrough came when I focused on the timing of the issue instead of a retraction or tension problem… you know what changes after 30mins of printing - the TEMPERATURE OF THE CHAMBER!:

  • I left the enclosure door wide open during the print, presumably keeping the filament cooler, and firmer, as it enters the drive gears and hot-end.

Result: a 10 hour TPU print completed without any jamming.

10

Thank you for sharing your positive experience and letting us know what works