In the last post we discussed the origin of plastic
products. Now, We will move a little deep into the manufacturing
process. We came to know that for plastic production, plastic injection
moulding was used.
1847 First condensation polymer (polyster) was produced by Jons Jacob Berzelius.
1861-62 Alexander Parkes invented first
man-made commercial plastic Britain. He named it Parkesine. It was
expensive to produce, brittle and flammable, but it could be heated,
moulded and used to retain its shape once cooled.
1868-72 John Wesley Hyatt developed Celluloid,
a plastic material made from a process that combined cellulose nitrate
and camphor. It was an improved version of parkes invention. Hyatt also
patented the first injection molding machine.
1909 Leo Hendrik Baekeland discovered Bakelite.
1930-37 Vinyl thermoplastics such as polystyrene, PVC and the polyolefins were developed.
1938 Dow invented Polystyrene plastic, which is still used widely today.
1939 A massive demand for cheap, mass-produced materials was generated during Second World War.
1941 Nylon was being used as a moulding material.
1945-1955 Gradually, Polyethylene and
polystyrene started replacing are older materials such as metals, woods,
leather and glass. Also, during this time, First extrusion screw
injection machine was built by American inventor James Watson Hendry.
1955 General Electric entered the market with Polycarbonate.
1955-65 High-density polyethylenes and discovery of polypropylene were major developments of this period.
1956 Patent was issed to W. H. Willert for reciprocating screw plasticator machine.
1960s Polysulphones, the PPO-type materials, aromatic polyesters and polyamides introduced.
1970s First gas-assisted injection molding
process was developed by James Watson Hendry, which permitted the
production of complex, hollow articles that cooled quickly. This greatly
improved design flexibility as well as the strength and finish of
manufactured parts while reducing production time, cost, weight and
waste.
1972-79 Plastic production overtakes steel production.
1990 Aluminum molds first used widely in injection molding.
Latest trends in Injection Moulding:
There are a number of significant developments in
custom injection molding
technology. These developments involve CAE (Computer Aided Engineering)
including the prediction of the properties of molded parts, innovative
experiments to analyze processing, new machineries (processing) and
recycling plastics.