Poor Surface Finish Due to Melt Zone Pressure Instability at High Speeds

When printing with highly elastic materials like Recreus TPU 70A at high speeds (100 mm/s), the system may experience melt zone pressure instability. Even with a high-flow 2.2 mm nozzle, the rapid extrusion rate can cause micro-fluctuations in the internal pressure of the melt chamber. Because TPU 70A is exceptionally soft and elastic, it fails to dampen these pressure variations, causing the material to exit the nozzle with inconsistent velocity. This manifests as surface ridges, uneven layering, and 'mushy' wall details that are not caused by mechanical friction or moisture, but by the fluid dynamics of the polymer failing to stabilize at high throughput speeds.

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