The circumferential screw speed from one machine does not directly relate to that of another machine, but it is a good starting point. This is because the material melt, shear, and flow characteristics within the screw channels will be different for each screw, so it is a machine-dependent parameter.

Question: Is circumferential screw speed a machine-independent parameter?

My Response: Circumferential screw speed is a neat parameter option for many molding machines as it measures the rotational speed of the outside of the screw. In theory, I like this parameter better than RPM when comparing different diameter screws, but it is not a fully-transferable machine parameter due to the differences from one screw to another when the diameter of the screw changes. Essentially, this data is a helpful reference when establishing the initial process. It is much more important to match the back pressure and recovery time as these are fully-transferable machine-independent parameters.

-Andy