Faygo Plast

Another object is to provide a self-starving screw member for use in a plastics twin screw extruder which substantially reduces torque and mechanical power requirements, improves volatiles venting and provides a high degree of uniformity of mass flow and pressure at the die.
Other objects of this invention will in part be obvious and will in part appear from the following description and claims.
These and other objects are accomplished in plastic extrusion line apparatus which includes a hollow cylinder having an inlet for containing a bed of solid plastic, a rotatable screw within the cylinder defining with the cylinder a helical channel for the plastic comprising in series, a feed zone beneath the inlet and a melting zone, by providing the improvement which comprises a solids decompression zone between the feed zone and the melting zone having increased free volume relative to the feed zone whereby before significant melting occurs the bed of solid plastic is decompressed to the extent that the channel in the solids decompression zone is partially filled. Once the plastic has entered into metering section of the barrel, it is ready to be extruded into a die sigle screw extruder. The die is attached to the barrel and it represents the final shape or profile that the plastic is intended to take. The plastic is forced into the die. As the plastic moves forward into the die, it will be separated by a mandrel, which is centered in the extrusion channel.