This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: P LASTIC LASTIC E E XTRUSION XTRUSION Introduction Extrusion is the process of converting a raw material, usually in the form of a powder or pellet, into a finished product by forcing it through a die. In the case of plastics, that material must first be heated to a near liquid state, then it is forced through a two dimensional die to form a continuous desired shape. For continuous extrusion, the pumping action is typically performed by a screw inside a barrel or a combination of screws. The polymers used are typically thermoplastics and are melted by heating the barrel. The opening in the die is the guide after which the extrudate takes its final form. Once exiting the die, it is cooled, either by ambient air or external means, and cut into desired lengths. There are three stages to this process, feeding the extruder, transition, and metering. The Single Screw Extruder There are many different types of extruders, but they fall into three basic categories; single screw, multiple screw, and ram. The most common, the single screw extruder, is what we will be concentrating on here. concentrating on here....
View Full Document
This note was uploaded on 03/18/2012 for the course ITEC 3290 taught by Professor Dunn during the Spring '12 term at East Carolina University .
- Spring '12