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Blow extrusion of plastic film. The manufacture of plastic film for products such as food packages, shopping bags, and continuous sheeting is achieved using a blown film line. [5] This process is the same as a regular extrusion process up until the die. There are three main types of dies used in this process: annular (or crosshead), spider, and ...
Die swell is an expansion of the melt as the pressure is released, and is dependent on polymer chemistry and die design. After curing, the solid, continuous part is drawn onto a take-up roller or cut into transportable lengths, depending on the type of part. This process may vary significantly depending on the type of die and extrusion process. [1]
This is an accepted version of this page This is the latest accepted revision, reviewed on 28 January 2025. Manufacturing processes This section does not cite any sources.
The polymer solution casting process utilizes a mandrel, or inner diameter mold, that is immersed in a tank of polymer solution or liquid plastic that has been specifically engineered for the process. Due to a combination of thermal and frictional properties, the polymer solution then forms a thin film around the mold. [1]
In 1964, M.C. Flemmings used unbonded sand for the process. The first North American foundry to use evaporative-pattern casting was the Robinson Foundry at Alexander City , Alabama . General Motors ' first product using these processes was the 4.3 L, V-6 diesel cylinder head , which were made in 1981 at Massena , New York .
In both types of extrusion the raw material must be plasticized to allow and induce the flow of the material in the process. Complex technical ceramic parts are commonly formed using either the injection moulding process or "hot wax moulding." Both rely on heat sensitive plasticizers to allow material flow into a die.
Extrusion coating is the coating of a molten web of synthetic resin onto a substrate material. It is a versatile coating technique used for the economic application of various plastics , notably polyethylene , onto paperboard , corrugated fiberboard , paper , aluminium foils , cellulose , non-wovens , or plastic films .
Plastic films are usually thermoplastics and are formed by melting for forming the film. [2] Cast – Plastics extrusion can cast film which is cooled or quenched then wound up on a roll. Extruded film can be stretched, thinned, or oriented in one or two directions. Blown or tubular process forces air into an extruded ring to expand the film ...