• Scam Alert. Members are reminded to NOT send money to buy anything. Don't buy things remote and have it shipped - go get it yourself, pay in person, and take your equipment with you. Scammers have burned people on this forum. Urgency, secrecy, excuses, selling for friend, newish members, FUD, are RED FLAGS. A video conference call is not adequate assurance. Face to face interactions are required. Please report suspicions to the forum admins. Stay Safe - anyone can get scammed.

3D Printing - machines owned by members


Premium Member
Post pictures of the problem.ie the poor prints and such?
Attached is a picture. The ring on the top right is the external support structure that handled the steeper part of the curve. Just below that on the cup the PETG did not adhere to itself very well and removing the raft and support cracked the base along the print lines. (1mm wall thickness).

The bottom ring with the rats nest is part of the inner support structure for the gear teeth. Once again it looks like the PETG didn't stick to itself and so as the extruder moved in a circle the filament pulled off and went straight. Once that starts of course there's usually nothing for the next layer to stick to. So you can see where it had stuck it continued to properly create support.

The solution has been to saturate both top and bottom with epoxy. In this case the steel re-enforced stuff which I think will end up being too stiff. The last one I did used W.E.S.T. epoxy (very old) and some strands of carbon fibre across the radial filament layers. Where it finally snapped was just under the gear teeth transition from teeth to 1mm wall.

As in the commercial (and very expensive) harmonic drives, the secret to these things is the cup gear.


  • BadPetG.jpg
    429.1 KB · Views: 7


Premium Member
I think the extrusion temp is too low - or the filament is cooling off too fast. Is there a fan running? turn it off? and try to bump up the temp 5C 10C. bed temp is too low? the filament guide says 90C for PETG. That's hotter than I usually run it. Turn it up?


Premium Member
Thought I'd finish my comments about my machine here. My extruder has a PTFE sleeve. I've had success of course with PLA and ABS. And I did a bit of printing with the PETG but as I reported it's never really gone well.

I hadn't realized that I was slowly destroying the extruder tube inside. Seems when printing PETG at 240C with a Teflon liner which has a melting point starting around 240C that I might have problems.

Didn't really until the small fan that cools the extruder failed. This fan is not easily visible where the printer is currently sitting. I hadn't realized it was defective until I couldn't swap PLA out. The PLA was stuck solid.

I've replaced the defective parts; fan, tube with new PETG. Working fine again. FailedFan-3 and FailedFan-4 is the replacement with the PTFE tube sitting correctly in a a new 26mm long threaded hot end holder.

On ordering replacement 3mmOD x 2mmID PTFE tube I discovered that 240C temperature rating. A bit more research and I found this article.

Key statement at the front of this article: " Not many 3D printers had all-metal hotends that could support it,"

Luckily I have some all metal hot end tubes but clearly the next time I want to print PETG I have to swap the feed tube with the PTFE insert with the one that is solid.

Oh and the reason I have all these spare parts? Because I also have what I call my POS Delta 3D Printer. (POS stands for Piece of S...). But that's another story...

Anyway, I have a couple of all metal hot ends (Bottom RH corner of ExtruderParts.jpg) so if I do some more PETG I'll use the proper hot end.


  • FailedFan-1.jpg
    192.3 KB · Views: 5
  • FailedFan-2.jpg
    167.4 KB · Views: 5
  • FailedFan-3.jpg
    142 KB · Views: 5
  • FailedFan-4.jpg
    145.6 KB · Views: 5
  • ExtruderParts.jpg
    316.6 KB · Views: 5
  • Delta-3D-Geeetech.jpg
    510.3 KB · Views: 5