An Introduction To Injection Molding Tooling
Injection molding tooling is designed by mold makers and is used to create a wide range of products that we as consumers often take for granted. The way that the process works is somewhat technical, but is not really all that complicated. It begins with material, typically plastic granules, being fed into a barrel which has been heated, and then mixing them. Afterwards, the materials will be fed into a mold where it will harden to match the exact shape of the mold cavity. But how are these tools created in the first place? Typically engineers or industrial designers will design a product and then the mold maker will be called in to build the molds, usually made from aluminum or other metal.
Injection molding tooling was first invented in the second half of the 19th century, for the most part by John Wesley Hyatt, an American inventor. He and his brother patented the first machine for the purpose of injecting molded plastics in 1872. It was a simple machine that used a large hypodermic needle like object to inject the plastic through a cylinder that was heated, and then into the mold. The industry didn’t really take off until World War II when the demand for inexpensive and easily mass produced products skyrocketed. New technological breakthroughs were also made during this time which also helped the industry to take off.
So, what modern applications exist for injection molding tooling? Actually, it can be used for a wide variety of reasons, such as to create custom products like milk cartons, bottle caps, packaging, dashboards, combs, and pretty much any other type of product that is created with plastics. This process is so widely used largely because it is a production method that allows for creating very large quantities of the same object. Other advantages to choosing this type of process include: repeatable high tolerances, several different types of materials at your disposal, low costs of labor involved, and parts rarely must be finished once molding process has been completed.
If you are going to be using injection molding tooling, it is important that you pay special attention to how the products will be formed in the machine, how they will be removed, and what the shape of the product will be when it is finished. In order to do so effectively, simply keep the following guidelines in mind. First, choose the same wall of thickness in all your designs. They should usually be quite thin, like between 1/32“ and 1/10”. It is sometimes tempting to use thicker walls in order to provide support, in which case you may want to try use additional structures like ribs instead. Finally, add a taper to the sides in order to make removal of the finished product easy.
