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Draft angle design is an important factor when designing plastic parts. Because of shrinkage of plastic material, injection molded parts have a tendency to shrink onto a core. This creates higher contact pressure on the core surface and increases friction between the core and the part, thus making ejection of the part from the mold difficult.
A film blowing machine involves one process used to make plastic film. Extruded tubular processing is most often used with polyethylene films but can be used with other polymers. [1] The film may be laminating film, shrink film, agricultural covering film, bags or film for textiles and clothing, and other packaging materials.
Parkesine, the first member of the Celluloid class of compounds and considered the first man-made plastic, is patented by Alexander Parkes. [4] 1869: John Wesley Hyatt discovers a method to simplify the production of celluloid, making industrial production possible. 1872: PVC is accidentally synthesized in 1872 by German chemist Eugen Baumann ...
Butch, femme, drag, camp, zhuzh and more are now in common parlance, thanks to Polari, as well as some quite spicy terms, like cherry, dish and more (but more on that later).
The petrochemical industry has been trying to save itself by attempting to rapidly expand demand for plastic products worldwide (i.e. through pushbacks on plastic bans and by increasing the number of products wrapped in plastic in countries where plastic use is not already as widespread (i.e. developing nations)). [5]
Plastic extruders are also extensively used to reprocess recycled plastic waste or other raw materials after cleaning, sorting and/or blending. This material is commonly extruded into filaments suitable for chopping into the bead or pellet stock to use as a precursor for further processing.
By contrast, a cold runner is simply a channel formed between the two halves of the mold, for the purpose of carrying plastic from the injection molding machine nozzle to the cavities. Each time the mold opens to eject the newly formed plastic parts, the material in the runner is ejected as well, resulting in waste.
Polymer engineering is generally an engineering field that designs, analyses, and modifies polymer materials. Polymer engineering covers aspects of the petrochemical industry, polymerization, structure and characterization of polymers, properties of polymers, compounding and processing of polymers and description of major polymers, structure property relations and applications.