Home >> Patent Categories

Patents

Patent Search

United States Patent 5342125
Douris , ê et al.

Feedscrew for injection molding and extrusion

Myers August 30, 1994

Abstract

A feedscrew for an extruder or molding apparatus has an elongated body with a helical thread formed thereon defining a first channel "A ". At the start of a mixing section, a channel "B " is cut in the center of the channel "A " and both channels are of the same pitch. The channels start at the same depth, but the channel A decreases in depth to a minimum and the channel B increases in depth to a maximum. The channel B then decreases in depth to a minimum and the channel A increases in depth to a maximum where the channels are again at the same depth. This channel within a channel configuration is repeated along the mixing section. The purpose of the arrangement is to compress and decompress the material being fed through the assembly to obtain the desired mixing action for low shear homogenization of the viscous plastic polymer.