What is Plastic Injection Moulding?

The first plastic injection moulding company was formed in 1851. The inventor of the machine, Alexander Parkes, believed that it would lead to a revolution in manufacturing. But that revolution was only made possible once a new plastic material called celluloid was introduced in 1868.

How does it work? The process is quite simple. Plastics are heated, deposited and injected into a mould and left to cool. The machine was patented in 1872, but surprisingly, it did not become popular until the outbreak of World War II. The incredible demand for simple plastic products like buttons, combs and pushpins made the machine an instant success, albeit one that took just over 70 years.

Let us take a moment to review the importance of design guidelines in the injection moulding process. Sure, there aren't many real design issues when it comes to making buttons or pocket combs. But in recent years, injection moulding has been used to create increasingly intricate pieces, parts and accessories. These often include computer and car parts.

As you might expect, these plastic pieces must be well-designed in order to work. What do we know? For starters, the thickness of the part should be fairly uniform. When there are inconsistencies in thickness, warping and sinking can and often does occur.

A simple rule of thumb for designers is that the corners should be at least one material thickness. This will ensure rapid cooling and better overall quality. Ignoring these simple steps will almost certainly result in an increase in customer complaints.