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5/10/2016 through 5/7/2016

* Note:  This collection is not complete.  Items may be missing and whole weeks may not be covered.  "Perfection is not of this world!"  Please send Maro missing patent numbers  for inclusion.  Experts are invited to send important, basic patents  or patents on new Topics. (RDC 4/29/2016)
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1 Topics

Processing (B)(1 Topic)(3 Subtopics)(2 Notes)(7 Patent Titles)(0 Patent Abstracts)(5/7/2016)  

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2 Subtopics

Extruders (D)(1 Topics)(0 Subtopics)(1 Notes)(37 Patent Titles)(1 Patent Abstracts)(5/10/2016)

Extrusion Applications (D)(1 Topics)(0 Subtopics)(1 Notes )(67 Patent Titles)(0 Patent Abstracts)(5/10/2016)

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1 Notes

1. Extrusion

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1. Extrusion  

“Plastics extrusion is a high volume manufacturing process in which raw plastic material is melted and formed into a continuous profile. Extrusion produces items such as pipe/tubing, weather stripping, fence, deck railing, window frames, plastic films, themoplastic coatings, and wire insulation.

In the extrusion of plastics, raw thermoplastic material in the form of small beads (often called resin in the industry) is gravity fed from a top mounted hopper into the barrel of the extruder. Additives such as colorants and UV inhibitors (in either liquid or pellet form) are often used and can be mixed into the resin prior to arriving at the hopper.

The material enters through the feed throat (an opening near the rear of the barrel) and comes into contact with the screw. The rotating screw (normally turning at up to 120 rpm) forces the plastic beads forward into the barrel which is heated to the desired melt temperature of the molten plastic (which can range from 200 °C (392 °F) to 275 °C (527 °F) depending on the polymer). In most processes, a heating profile is set for the barrel in which three or more independent PID controlled heater zones gradually increase the temperature of the barrel from the rear (where the plastic enters) to the front. This allows the plastic beads to melt gradually as they are pushed through the barrel and lowers the risk of overheating which may cause degradation in the polymer.

Extra heat is contributed by the intense pressure and friction taking place inside the barrel. In fact, if an extrusion line is running a certain material fast enough, the heaters can be shut off and the melt temperature maintained by pressure and friction alone inside the barrel. In most extruders, cooling fans are present to keep the temperature below a set value if too much heat is generated. If forced air cooling proves insufficient then cast-in heater jackets are employed, and they generally use a closed loop of distilled water in heat exchange with tower or city water."

Wikipedia, Extrusion, 6/4/2012

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Copyright 2016 by Roger D. Corneliussen.
No part of this transmission is to be duplicated in any manner or forwarded by electronic mail without the express written permission of Roger D. Corneliussen

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Roger D. Corneliussen, Editor
Professor Emeritus
Materials Engineering
Drexel University, Philadelphia, PA
Editor
Maro Publications
Telephone: 610 363 1533
Email:
cornelrd@bee.net
Website: 
http://maropolymeronline.com/