Plastics are synthetic materials that can be deformed and mold into shape through the application of heat, though the word “plastic” can be used in other terms that are not synthetic materials to denote malleability and ability to be shaped or to show elasticity, this term is usually seen when dealing with properties of metals. However, plastic as a synthetic material refers to the material produced by the polymerization of the polymers.

Plastic by classification is so wide that it has both synthetic and semi-synthetic organic compounds, and such compounds are malleable such that they can easily be shaped with the application of heat. The processing and production of plastics can be done in different forms but the commercialization has been known to involve three methods only which are:

INJECTION MOLDING:

This process had been a method of polymer processing in the 1870s until other plastic forming machines were developed in the 1930s. The process involves injecting molten plastic materials into their various molds, it is usually applied in the production of plastics by parts, either as uniform parts or parts of variable shapes. Beside plastic production; injection method of production can be applied to other materials such as metals for the production of parts. The method has proven successful and best for the production of plastics with intricate shapes such as; chairs, tables, buckets, bowl, flasks, etc. The method can also be employed in the production of glasses, and elastomers. The plastics processed using the method are usually; Thermoplastic and thermosetting polymers.

The process involves feeding the heated and mixed polymers into a mold cavity by forcing it with the plunger into their various molds to take the configuration of the cavity.

EXTRUSION MOLDING:

This is another method of plastic production which took the industrial sector in the plastic production processes, it came within the 1930s as an improvement to the already existing method but quickly found its use to be separate from the previous method since the method introduces what can be referred to the as “continuous molding process”. It is a process used to produce objects of fixed cross-sectional profile. The production of plastic pipes, plastic bars, plastic springs, and plastic tubes, etc. has been made possible through this method.

The process involves, pushing a material through a die of the desired cross-section, such material can be the molten polymers which can be forced through a die by the application of spiral screw in the machine. Plastics made through the method usually have a good surface finish.

BLOW MOLDING:

This is the third largest and fastest growing method of plastic production, it is a manufacturing process by which hollow plastic parts are formed, it is usually employed in the making of plastic bottles, plastic water tanks, and jerry cans, etc. The method has three types which are:

Extrusion blow molding, injection blow molding, and injection stretch blow molding.

The blow molding method involves melting down the plastic and forming it into a  parison. The parison is a tube-like piece of plastic with a hole in one end through which compressed air can pass. The parison is then clamped into a mold and air is blown into it. The air pressure then pushes the plastic out to match the mold.

 

  • Yum