I’m so close to finishing up my first two chairs, and for the life of me, I can’t get a finished strap or handle. These are the last parts to complete.
For the handle, I cannot get past the initial overhang. I know this has been discussed in multiple other threads, and I’ve tried many of the suggestions: retraction and no retraction, painted, auto tree, and normal supports, adjusting Z gap, etc. I cannot get a clean print on the overhang. It always turns into the TPU curling upward in some spots and drooping in others when not supported, or it’s a mass of TPU supports that refuse to detach without tearing everything it touches.
I have a different issue on the straps. I get a good print on the majority of the part, but the small tower of TPU at the loop moves while printing and creates a significant weak spot.
I need some advice.
Have you printed a calibration cube?
Try this model - https://makerworld.com/en/models/1045337-the-perfect-tpu-profile#profileId-1031040
I started with his profile then modified it a bit.
Is your TPU dry? I’m not sure why the bumps on the handle.
I’ve had some major challenges with TPU, stick with it
I’d also check this out, my thread - Help with TPU Straps
What profile did you choose when printing for the TPU? And drying, bumps/warts usually occur from lack of that.
I’d recommend trying the generic TPU profile if you haven’t already. It’s slow, but yields good results, and then you can tinker with settings at another point.
I have also followed all the recommendations and do run into trouble with the stop ends like you on occasion. I don’t really understand it because some turn out perfect then others not even usable on the same setup. Some of them I have noticed look weird but they are still fairly strong so I still use them on the feet straps and the stronger ones up top.
The best luck I have with the straps is when I print them by object on the plate. I think the less movement helps keep the end lined up. I know some have mentioned painted supports for that part as well, but I haven’t had to print any new straps yet to try that.
That TPU is wet. Dry it and then print directly from a dryer or a box with desiccant in it. You’ll see a huge improvement.
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What Gramps Said…
This has been the final thing that has fixed my TPU challenges…
I printed the base from Makerworld
https://makerworld.com/en/models/215704-dry-box-cereal-box-spool-hygrometer#profileId-234889
Well I just happened to have a bunch of 608 RS bearings lol, and a few cereal boxes so I figured for a 5 hour print, I’d give it a try. Using the empty spool on the Aux spool holder to direct the TPU works great. I’ve been pulling from a full spool and it has been spinning fine, no under extruded issues at all. First layers have been great. I did save the Amazon box just in case…lol
I started with Generic TPU, the changed the profile to match values on manufacture TDS or https://3dfilamentprofiles.com. Then I run some test object to dial it in from there.
The burps are not from moisture. It’s too much pressure after playing around with flow ratio and max volumetric speed. It was too high on that test and caused blobs. Each on align with all the seams in the slicer
I feed the TPU directly to the print head from the dryer. On that print it had been in the dryer at for a week.
I wish it was that simple of a fix but the TPU lives in a dryer with desiccant.
I think the next step is the test cube @Little_Charlie suggested and printing by object on the straps to minimize movement like @thumbsup said.
Everything else in TPU printed perfect except, if it was a moisture issue, it should have shown up on the tires, harness and other straps.
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