Applications For Injection Molding Technologies

By Henry A. Parker

Think about injection molding and your mind immediately goes to plastic army men and other tiny toys and accessories that toddlers love to cram in their ears, nose, throat, etc. The process, injecting fluid material into a mold, applies to all sorts of other materials, too. Metals, glass, confections, polymers and elastomers can all be molded and then custom machined to produce everything from a jelly snakes to car doors.

Mobile phone covers, toy bricks, plastic forks, styrofoam cups, metal scissors and the fans that go inside computers to keep them from overheating while you are playing Candy Crusher, all of these items are fashioned using IM technology. The process, which was first used in the mid-19th century, is amazingly versatile and yields gizmos and widgets for everything from kitchen gadgets to the International Space Station.


One use for the IM process to which we can all relate is in the production of toy soldiers and collectible military miniatures. There are miniature troops to match practically every war in history. The price of the piece often corresponds to the seniority of the figure. The Duke of Wellington, for example, will cost more than his minions, although Richard Sharp would probably fetch a pretty penny.

Electric train collectors are also avid users of IM technology. As with miniature soldiers, the pieces here are made of molded metal and painted. The authenticity and level of detail of the train driver, the little mailmen, babies in buggies, etc., is a wonder to behold.

The starting material, whether polymer, metal or thermoplastic, is pulverized into a fine dust and, in the case of metal, mixed with what is called a binder to produce what is called feedstock. The feedstock is fed through a hopper and passed through a heater while being fed through a tube by a linear actuator. The material is melted into a liquid and then fed into a mold and then cooled.

The range of objects that can be manufactured using this technology is amazing. There are a lot of parts that one would not intuitively think were made this way. Even the parts for the machines that do the injecting and molding have injected and molded parts inside them.

Many different industries feed into the IM process. Computer software, polymers, binders and machinery are all necessary to fuel the process. It will, however, be fun to see how IM technology evolves in response to the up and coming 3D printing process.

About the Author:

Henry A. Parker has taught plastics molding techniques for over 15 years. He specializes in injection molding and thermoforming. If you are interested in learning more about injection molding services then he recommends you visit his friends at PTM: Plastic Injection Molding Services.