Tips for TPU printing?

[JOEPRO]

Again im new to 3zd printing so talk to me like I have absolutely no clue

Hence I ordered a roll of TPU to try in my enclosed Flashforge Adventurer 5M



This is in relation to a cup holder im going to try and design for Mercedes w124 cars like this link

Mercedes W124 C124 A124 S124 Custom Cup Holder Insert Cupholder for Center Console Storage Box

Mercedes W124 C124 A124 S124 Custom Cup Holder Insert Cupholder for Center Console Storage Box Our cup holder is available for all 124 models that were

octoclassic.com

I have read that TPU needs to be dried quite a bit. Prone to damp.

Any other tips from members who have experience with TPU?

 

[ajlelectronics]

Feed it from above via the shortest direct route into the extruder, avoiding tubing and sensors. I made a gantry to carry the filament roll directly over the top of the extruder. Your printer needs a direct drive extruder, not an external filament feeder like the Ender 3s.

Print it SLOW. 25mm/s is plenty. Bed should remain unheated.

 

[JOEPRO]

Feed it from above via the shortest direct route into the extruder, avoiding tubing and sensors. I made a gantry to carry the filament roll directly over the top of the extruder. Your printer needs a direct drive extruder, not an external filament feeder like the Ender 3s.

Print it SLOW. 25mm/s is plenty. Bed should remain unheated.

Thank you I will look into that when I get to it. I read this that my particular printer works well with a 0.6mm nozzle on TPU. It came with a 0.4mm nozzle only. So I have ordered a genuine 0.6mm nozzle £19 shipped from Aliexpress £20 cheaper than amazon so im willing to wait a week or two

 

[hotponyshoes]

I've had rolls of tpu open for a couple of weeks or more and not had any problems with damp.
I have printed it when it's been damp (you can hear it popping) but that doesn't seem to cause any real issues as long as the other settings are ok.

Main tip would be to get the bed levelling sorted perfectly and get your first layer height/offset bang on. After that it prints like anything else.

Supports are very hard to remove and its not great for overhangs so I'm not sure it's actually the best thing to print that cup holder with but you could scale the model down to 25% and print a test run to save time and filament.

 

[ajlelectronics]

I read this that my particular printer works well with a 0.6mm nozzle on TPU

It way well do, but the standard 0.4 will be fine.

 

[hotponyshoes]

Thank you I will look into that when I get to it. I read this that my particular printer works well with a 0.6mm nozzle on TPU. It came with a 0.4mm nozzle only. So I have ordered a genuine 0.6mm nozzle £19 shipped from Aliexpress £20 cheaper than amazon so im willing to wait a week or two

View attachment 503105

I mostly use a .6 nozzle but didn't really get any extra problems with a .4
I actually had more problems with a .6 but I think that's because I was trying multiple things at once to speed up the print times.

That link you posted mentions self-extrusion at higher temps. I expect that is because the tpu compresses in the feeder and acts like a spring. I find that higher temps result in fewer jams and better print bonding.
It does leak on heating but I deal with that by printing a 200mm line before the print.

 

[Prajna]

I'm printing tpu just now. I found my tpu prints nicely with the bed at 30 deg, nozzle at 240 deg, 5mm brim and speed seems to be around 40mm/s It's a bit stringy and I understand drying helps with that but it's no problem for me.

 

[daedalusminos]

A lot is going to depend on the shore hardness of your TPU, I regularly print with Ninjaflex which is shore 85A - pretty soft.

TPU generally gives good adhesion on an unheated textured PEI bed with excellent layer adhesion but you'll need to print slower than the rigid filaments - these are the precautions I take on my Prusa Mk3s:

Slack off the extruder tension - the Prusa extruder is not a totally straight path for the filament run and 'biting' on the filament too much can cause a kink and then a jam....so I use a low tension so it's more like a clutch. In view of this you need the spool to rotate freely, I have mine mounted on bearings.
Retraction: turn off retraction since pulling the filament in and out of the hot end is likely to case a jam. The result of this is that the nozzle will tend to ooze resulting in stringing. You can minimise the effect this has on your part by setting the slicer to 'not cross perimeters'. Also printing multiple models on a bed is best done sequentially.
Hot end temperature: Fine tune the temperature to within a few degrees. Too hot and the layers will melt together and you'll lose dimensional accuracy, too cold and and you'll lose layer adhesion - it's pretty obvious when this happens though. The slow printing speed means that heat is likely to build up in the part with small extrusions areas and therefore the part cooling fan may be required.
Infill: Never set to 100%, if you want a solid part set to 95% (or similar) - this will prevent over extruding from causing a jam.
Speed: Ultimately you're limited by how fast you can push the filament into the hot end without a jam so I use the flow rate to limit the print speed.
Layer height: Since you can only push so much filament into and out of the extruder you may as well print thinner layers faster - I always print 0.2mm layer height on a 0.4mm nozzle .

 

[hotponyshoes]

Infill: Never set to 100%, if you want a solid part set to 95% (or similar) - this will prevent over extruding from causing a jam.

Interesting that you found this to be the case.
I'm only printing solid parts and I found they were starting to fall apart after heavy use when set to 100% infill.

I have kept the infill at 100% and increased the flow to 105% which seems to have solved the problem.
Although I'm using a bowden tube rather than a direct drive so I may well be suffering from under-extrusion to start with..

The only jams I suffer are on the first layer (excessive back pressure)
That's usually cured by adjusting first layer height, offset and bed levelling.
Might be an issue on subsequent layers if you had model geometry that created similar conditions?

 

[daedalusminos]

Again im new to 3zd printing so talk to me like I have absolutely no clue

Hence I ordered a roll of TPU to try in my enclosed Flashforge Adventurer 5M

View attachment 503104

This is in relation to a cup holder im going to try and design for Mercedes w124 cars like this link

Mercedes W124 C124 A124 S124 Custom Cup Holder Insert Cupholder for Center Console Storage Box

Mercedes W124 C124 A124 S124 Custom Cup Holder Insert Cupholder for Center Console Storage Box Our cup holder is available for all 124 models that were

octoclassic.com

I have read that TPU needs to be dried quite a bit. Prone to damp.

Any other tips from members who have experience with TPU?

Obviously only a need to print the 'fingers' in flexible TPU - I think I'd be a bit concerned how well they'd hold up in a hot vehicle interior. You might find if a cup is left in situ on a hot day the fingers 'creep' and lose their spring