Definition: ''Any polymer process which gives a partly or fully foamed product.” (Science dictionary)
Foam molding is a manufacturing process that creates parts of a product and artefact made out of foam. The foam molding process consist of mixing foaming agent and base resin in melted polymer, creating a mixture that will be injected into a mold, that will solidify and become a part or an object.
In 1872 the American inventors John Wesley Hyatt and his brother Isaiah Hyatt patented the very first injection molding machine. The machine was relatively simple compared to modern day technology. The way the machine worked was like a large hypodermic needle, it was used a plunger like device to inject plastic through a heated cylinder into a mould. The machine could produce everyday objects such as buttons and collar stays. The industry progressed slowly over the years and it expanded dramatically in the 1940s during the post-World War II economic expansion that created a massive demand of inexpensive mass-produced products.
Later on, the American inventor James Watson Hendry created the first screw injection machine in 1946, with the screw injection; the machine was much more precise in terms of the speed of injection and also allowed the improvement in quality of the articles produced. The advantage that this machine also had was the fact that the materials were able to be mixed before the injection which facilitated the task. Finally, in the 1970's James Watson Hendry went onto develop the first gas-assisted injection molding process(figure 1), this new invention permitted the production of more complex commodities such as hollow items that cooled quickly. This process greatly improved flexibility of the design of components as well as the strength and finishing in manufactured parts while reducing the cost, weight, time and waste accumulated during production.
The Injection Molding industry has evolved over the years from producing simple artefacts such as buttons and collar stays to producing a vast variety of heavy duty, high end products for many different industries such as automotive, toys, consumer, packaging and construction. Injection molding is the most common modern method of part manufacturing, absolutely essential to mass producing, high volumes of the same object.
On another note Foam rubber was originally made out from natural latex, rubber trees used to produce a white sap. It was used by the ancient mayans and aztecs for waterproofing purposes and it too was heated to create toys such as balls as early as 500 B.C. In the early 1900's a first patent for synthetic rubber was discovered but several decades later a process was invented for foaming latex. Another process was developed for making foam with an isocyanate based material in 1937. Since World War II natural foam has been replaced with styrene-butadiene and today the most commonly used foam product material is polyurethane. Foam...