Patent ID: 6227692
Filing Date: 2001-05-08
Classification: B29C

Abstract:
A screw apparatus for supplying plasticated plastic material to an injection molding machine comprising:a screw housed within a barrel;said screw including a feed section for receiving plastic material in solid form;said screw further including a compression zone for receiving said plastic material in solid form from said feed section and for initiating melting of said plastic material;said screw further including a first melting zone positioned adjacent said compression zone for receiving partially melted plastic material from said compression zone, said first melting zone having two side-by-side channels, each said channel having a first portion with a first depth and a second portion with a second depth and the first portions in a first one of said channels being offset with respect to the first portions in a second one of said channels;said screw further including a mixing zone adjacent said first melting zone for receiving melted plastic material from said first melting zone, said mixing zone being formed by more than two channels of substantially uniform width;each channel in said mixing zone having a depth which gradually decreases from an inlet of the mixing zone to an outlet of the mixing zone;said screw further including a second melting zone positioned adjacent an outlet of said mixing zone, said second melting zone having two side-by-side channels, each said channel of the second melting zone having a first portion with a first depth and a second portion with a second depth and the first portions in a first one of said channels of the second melting zone being offset with respect to the first portions in a second one of said channels of the second melting zone;said barrel including an inlet adjacent said feed section of said screw, an outlet adjacent said second melting zone for discharging plasticated plastic material, and a solid wall structure completely surrounding said screw and extending from said inlet of said barrel to said outlet of said barrel; andsaid channels in said mixing zone being spaced from said solid wall structure surrounding said screw by a distance which allows solid particles of a particular size to pass through to said second melting zone and so as to trap solid particles of a size greater than said particular size.