Printing TPU - Speeds question

Hey everyone. Hope you’re all safe and healthy.

I’m printing a couple Scout 32s for my kids to play remote hide and seek with and am staring at a spool of TPU. I tried printing it yesterday with no real success but had other tune ups to address on the printer. Those are all fixed up now.

I’ve been told and have been reading “go slow” and “keep it constant”. I’m still using the default recommended start settings from V1 so already printing quite slow (30mm/s). Should I slow it more? And how/where/how slow?

I’m using Slicr so not a bazillion setting availablenlike you’d find in Cura.

Might give some pointers.

Yes, got a few pointers from there. I’m headed out (scary! ; ) to grab some wide painters tape right now. The glue stick worked OK yesterday but what a PITA to clean off. I missed the bit about extrusion multiplier adjustments. I’ll look more closely at that as well.

Any speed pointers?

Nope! My tpu is still sealed in its original bag.

What TPU are u using?
Yes printing slow is how it works.

I have been printing with flexible filaments for a while.

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I have 210°C and 20mm/s
This works for the CR10 Mini I am working with.

I’ll try that as a start. Thanks! I’ll let you know how it goes Barry. Maybe you’ll crack your bag open :wink:

In Slicr are there any settings I should paynparticular attention to? I don’t think it has settings for things like accelerations, retraction etc, does it?

This is one of the keys to having no stringing.
In slicer I have mine set to:
Retract length = 4mm
Retract speed = 70mm/s
Minimum travel after retraction = 1mm

I’m running ninjaflex, by the way.

I got this stuff (next day with Prime) from the Amazon. It’s called Priline and it supposedly has a shore value of 98a so not as flesh as Ninjaflex.

Haven’t tried yet by the way. I have a few more 2 hour prints to do before I pull the PLA. I’ve got the gcode file ready though.

It’s going well on the taped bed at 20mm/s. I turned the retraction right off which is causing some stringing between the flaps of the tracks but it’s forming a perfect triangle so I don’t know if it’ll hinder performance or not. I’m going to print two this way and then try the above retraction setup and see what difference I get.

The amount and speed of the retraction might need to be played around with.

So there was some badness in the main band and I think it had to do with the infill setting I used (90%). Don’t ask me why I didn’t use 100 - I don’t know. I’m reprinting with the retraction now and 100% infill and it looks ok so far. It’ll finish in about 20 minutes. I can DEFINITLEY see the retraction happening and the print to this point has been completely clean. If nothing else I’ve learned a thing or two about retraction and stringing so thank you for that.

Well, the print was good looking but had the same flaws as the last print in terms of integrity. Any thoughts as to why this is happening? Suggestions on what I might try to adjust?

I haven’t tried printing with any flexible filament, but I’ve read about it. 8^) Like @barry99705 I have a spool still in the wrapper, so take this with a grain of salt.

The surface finish on that print looks like it has absorbed too much humidity. I have printed a bit of nylon, and that is what it looks like when it’s been left out too long and absorbed moisture too. You might try cooking the spool at maybe 150*f.

With regard to the part falling apart, I think I’d try printing a little hotter. Maybe 5*C? I’m sure I read somewhere that tpu pulling apart was an indication of low print temp, but I don’t remember where.


This has been the most frustrating 24 hours OF MY LIFE!!!

Ugh this stuff is a bugger. So I got three belts to print yesterday without real issue other than a crappy finished product that fell apart. I redid the model and it printed in a whole different way than the gcode I made from the Thing files did. His file made gcode that printed a bunch of little elements and then bound them together. My file printed the inside perimeter, then the outside and then the infill. WAY WAY WAY stronger finished piece.

However I can’t seem to get more than 1.6mm off the buildplate before I start air printing. WTH? And no clicking to speak of. Well, it was clicking this morning but I caught it every time. Since then though - no extruder clicks. When I pull the filament there is a single curl in it like it corkscrewed in the throat. Not a clog at the nozzle. It seems to jam at this bit in the throat.

As I said, this stuff ran fine yesterday all the way to 13.5mm off the build plate. Why on earth won’t it get through a print today? I even put a fresh nozzle on.

I’ve tried speeds as low as 10mm/s, retract, no retract, cooling, no cooling, hot nozzle, not as hot nozzle…I’m at a loss here. Especially because it sailed through the prints of the bad model yesterday.

The PTFE tube needs to be as close to the drive wheel as possible.
By the way are you using a Bowden or direct drive?

I’m using my MP3DP - direct drive. I have a Bowden machine but didn’t even wanna try it after reading about the added complications that can cause. My throat is crazy close to the gear. I don’t think that’s the issue. I wonder if the new fan is actually not keeping the heat creep down from the hot end?

The new fan is a three wire fan and I only hooked up the pos/neg, not the third wire. Should I maybe look into that? The fan is dead silent (but I was told this brand is dead silent). Still doesn’t explain why I got this three prints on Monday though. Maybe I should try a 30mm/s print? Might be fast enough to prevent the heat from making the filament coil in the throat? I’ve had enough blown prints it can’t hurt to try I guess.

I have seen temp swings that are just far enough out of the processing temp of the filament but not enough to trip an error for the hot end.
I found my printing temp and layer adhesion by printing 2 8mm posts soild at .3 ,layer height about 20mm apart.
Start off at 30mm/s and start hot. Every few layers (5mmish) adjust the heat down 2*C.
Printing hot will cause bubbles in the print. Adjust until they go away, you found your TEMP to print (make a note of it).
Then move to speed, do the same thing.
But I would say 30 is usually the sweet spot.