TPU/TPE Calibration Test Print Collection for Ender / CR-10 Bowden Machines

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INTRO / BACKGROUND: This is a small collection of tests I designed to dial in, and calibrate my ender 3 style printer for flexible material, although in the harder end of the sprectrum (about 95A - 98A). I made these because I did not find any suitable TPU calibration prints, or tests designed to explore the abilities of TPU materials, and so I share these here for others to find, use, and modify. Note that these tests were made for a 0.4mm nozzle, and on an Ender 3 style machine eith a bowden setup, for a relatively hard material, and not some of the softest filaments out there. These tests are small, quick, and designed to quickly give the user essential info about their material behaviour. In-depth tests are encouraged at later states, and I'd love to see some of them shared around here! PART DESCRIPTIONS: flow test: a simple cube with a wall thickness of 0.4mm, a good startup. meaasure the wall thickness to get a sense of under/over extrusion, check the quality of the thin-walled layers (proper bonding, buckling etc.), and see the stretchability of the material by squishing it to your heart's content. Also note the top layer quality, and whether or not you need a brim to hold your prints in place. Now, you should do a stringing tower test, or a temperature tower test (OR BOTH!). You can use the classic ones, which is why I don't have any here. RETRACTION SHOULD NOT BE TURNED OFF! Stretch test: next logical step is a test to check for dimensional accuracy of solid parts, as well as get a sense of how much elasticity you actually get in the parts - provided they're thin enough. The wall test gave a sense of deformability, but not stretching like this. The band is very thin, about 3 layers thick at it's thinnest, then double that, to give a sense of how thickness impacts the stretching. finaly, there are 2 knobs on the other side of the band. The knob closest to the holes has the same dimensions as the hole, and can be used to judge accuracy - if the knob passes through the holes without friction, that'll tell you something about the clearances you get. The knob at the end is 1mm smaller in both length and width, and usefull if you want something to compare to. TPU support test: most sources agree that 40-50 degrees are about the biggest overhang you'll get away with before needing support. This little test explores a few things; 1) does the filament risk warping? There is a thin section here to test it. 2) can it handle overhangs of 45 degrees and how does it compare to 50 degrees? the slopes are marked; the first 2 are 45, the last 2 are 50. In the slicer, make sure it will not generate support for overhangs of 50 degrees or below. The test is supposed to try building those angles without help. 3) there are 4 platforms under which you need support. Take this oppertunity to try a few different support patterns, densities, etc. and you can compare the results on the same print or multiple copies. Check for how easi it is to remove both from the underside of the print, as well as from the bed. The long thin strip is also attached to the support to see how well support sticks when it grows from the part, as well as how well support from bed and parts integrate as you go higher up the layers. You may also check for buckling strength of the support towers. 4) lastly, check surface qualities - did the text print well? What about the underside of the 50 degree angles? Texture test: this is test designed for the Cura slicer, as the STL file itself does NOT have a texture. Under experimental settings there is the ability to create a textured outer / inner surface, by intentionally jostling the nozzle. i made this organic handle shape to test a few things; 1) how well does the material work as a texture? 2) you can vary the texture settings as you go up the handle, to compare a few. 3) how well does the material support the bottom of the handle? There is a curved section that requires support. 4) again with the squish test, this time a lot thicker. TPU torture test: this last one is optional, and you're not necessarily aiming for a perfect print. this tests a lot of stuff; inner and outer diameters, tall thin towers, stringing, bridging vs. no bridging, surface finish, how well does an infill pattern support top layers, warping, wall thickness, and a more detailed overhang test. Make of this test what you will. J3_ out.