TPU hollow ball pit balls, no supports, no deformation, no warping, low Z-seam, perfect printing at 0-10°C room temperature

After more than 20 printing tests, various issues with printing hollow TPU balls in winter have been resolved, and the printed result has the texture of a ball pit ball

Summary of problems encountered when printing TPU in winter and their solutions (personal summary log):

1. First layer appears uneven with bumps, which can later cause TPU to jam with layer lines, or even lead to PETG or PLA jamming and spaghetti: Low ambient temperature causes uneven extrusion, so the printing temperature should be increased by 20-40 to ensure consistent temperature of the freshly extruded filament

2. Printing extra-large TPU models causes wobbling at height: Change tree supports to normal supports; add painted supports to prevent the model from leaning or having overhangs; arrange supports vertically as much as possible to reduce wobbling of the Y-axis build plate; reduce acceleration to below 500, ideally below 100

3. When printing a hollow TPU ball halfway, one side warps upwards: This is caused by the fan cooling and shrinking the expanded area, so just set the fan to 0 or 10

4. When printing the ball halfway, there's yellowing or blackening, accompanied by slight layer breaks: This means either the fan speed exceeded 10, or the printing temperature needs to be increased by 10

5. When printing the top of the ball, layers don't adhere: Bridging sag causes each layer to sink, so you must set the top shell layers to 5 or 6, and ensure strong cooling for bridging

6. Z-seam is too prominent, even thin enough to be translucent: Restore all adjusted Filament Pull Back and seams to default, then lower the printing temperature as much as possible