@gr5 Thanks for the reply. I dehydrated the TPE filament within a food dehydrator and made an air tight dry box to print directly out of with a bowden tube. I seem to have got the retraction setting down to 5-5.5 mm and 45 mm/s.
However, I now realized my print, (a simple tower with small 90 degree angle overhangs) is flimsy from the bottom but structured yet flexible on the upper. I have the infill density set to 20% with a grid pattern and the only layers on the bottom of the print affect are the same layer height as those with supports...
Any advice on how to fix this issue?
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gr5 2,189
TPE? TPU? I'm wondering if the filament absorbed water. When filaments absorb water, the water turns to steam as it prints and that causes steam bubbles in the filament. The filament expands more than usual. You get much more stringing and blobs and things stick together more than they should (because they expanded). Some filaments (e.g. PLA, ABS) are not really affected by humidity or only subtly affected. But many filaments (particularly PVA and Nylon) can absorb too much water in just a few hours. It's usually easy enough to dry the filaments (e.g. for Nylon 75C heated bed temp overnight with towel on top should dry out any loosened filament but 75C for PVA might soften it enough to ruin it).
If you pay attention you can see steam coming out of the nozzle as you extrude. Maybe not for the first 10 seconds as you have previously heated filament sitting in the nozzle but pretty soon after. Try the MOVE feature to extrude for a full minute and look for steam.
You can also see that the filament goes from shiny (when dry) to foamy/matte (when wet).
The key parameters are flow and your filament tension. Make sure tension is at the minimum. The higher the tension the less you are actually extruding as it squeezes to a smaller cross sectional area as it passes through the feeder. For most filaments, flow is at 100% but for flexibile filaments you often see flow values above 100% to compensate for this feeder compression. I'd check the flow in cura 4.8 that you were using and again in cura 5.0.
For retraction you want the exact amount for the filament to be resting in the bowden (no pressure). You don't want to actually pull out of the heater block. While printing you can see the filament is pushing up on the top of the bowden arc. When retracting it should just barely rest at the bottom of bowden at the top of the arc. No extra retraction or you can suck air into the nozzle which is worse than no retraction at all.
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