Some of the key factors impacting the process pressure of TPU extrusion are:

Material Properties: The viscosity of the TPU material affects the extrusion pressure. Higher viscosity materials require higher pressure to extrude effectively. Factors like TPU grade, molecular weight, and additives can affect the material's melt viscosity and flow characteristics, thus influencing the extrusion pressure.

Melt&Extrusion Temperature and Residence Time: The melt & Extrusion temperature and residence time in the extruder can influence the TPU's properties and its flow behavior, thus impacting the required extrusion pressure. Higher temperatures can reduce the viscosity, resulting in lower extrusion pressure requirements

Extruder Design: The design of the extruder, including the screw geometry and the barrel configuration, can impact the required pressure for TPU extrusion. An efficient extruder design can help in achieving optimal pressure and melt flow.

Screw Speed: The rotational speed of the extrusion screw affects the pressure required for TPU extrusion. Higher screw speeds generally result in higher pressure.

Die Design: The design of the die or the extrusion nozzle also plays a role in determining the required pressure. Factors such as the die diameter, land length, and taper angle can influence the pressure needed for extrusion.

It's important to note that the specific influence of these factors on TPU extrusion pressure may vary based on the extrusion equipment, process parameters, and TPU formulation used. Optimal adjustments of these factors should be determined through experimentation and process optimization.