The use of precision injection molding has become more common across all industries due largely to the availability of different material to use in the process. There is a range of different materials including thermoplastics, resins and elastomers now used to create components for electronics, medical devices and equipment, dental equipment, and in laboratory work.
There has been a very rapid evolution in injection molding into what is now termed precision injection molding in these highly specialized types of production requirements. Understanding where the process has come from in a very short period of time helps to understand while it has allowed important breakthroughs in other technologies.
The Materials
The first development of polymers was in 1847 by a Swedish chemist. This was a rudimentary condensation polymer made from combining glycerin with tartaric acid. However, the first plastic polymer was not developed until 1861 by a British inventor, and this could be melted, molded and cooled to retain the shape of the mold.
An American developed Celluloid, an enhancement of the British polymer option in 1868, and then later in 1872 also co-patented the very first injection molding system or machine. This was a very slow process using a needle and plunger type of mechanism to fill the molds.
It was World War ll that actually sparked the development of precision injection molding, although not in the small forms found today. This typically produced colored plastic items, and they used a screw type of injection system which was faster and much lower cost.
The Recent History
As the process became faster and much more efficient, it became possible to create specialized polymers as well as more and more refined equipment, processes and molds. Since 1995, the number of polymers available has increased by just over 700 possible options in resins per year, many which are combinations and blends of existing resins.
By using blends of resins and polymers more detailed, finer and more advanced precision injection molding became possible. At the same time, technology allowed the use of computerized design systems to control the inject process, allowing for incredible repeatability and specific control for tolerances.
This allowed precision injection molding to be the ideal option for mass production or small batch production of parts that are completely identical to each other. With this precision, the injection molding process truly did become precise, opening up new possibilities for creating medical devices and components for any type of application.