Get Your Feet Wet in The World of Plastic Manufacturing: Compression Molding 101

Imagine the rain is falling in streaks. Not drops, not buckets, but a long and steady sheet of water that falls to the ground, almost instantly planting stream that spout forward into a brown muddy torrent, carrying rock, stone, and sediment wherever the deluge cares to take them. You look out the window, and the first thought you have – to go back to bed and listen to the rainfall – is the last thing you can do. Naturally, you do the only thing you can on a day like this. You step into your rain boots and you walk into the wet, wet world.

You think to yourself, “Wow, rainboots are an amazing thing!” and in that very moment, without even realizing it, you’re thankful for a little area of manufacturing we call compression molding. Compression molding is a method used to mold a preheated plastic polymer. To do so, the material is first placed in an open heated mold. This mold is then closed, pressure is applied to force the material into all the nooks and crannies in the mold, and the pressure and heat are maintained until the material being molded has completely cured hardened.

The first recorded use of the process was by Leo Baekeland in 1907 using phenol-formaldehyde resin. The equipment was primitive and it would continue to be for another 20 years when a crude compression machine was invented and the modern compression molding process was born. When this happened, the original resin used was called Bakelite, in honor of the creator of the process. In the mid 20th century, the invention of the automobile and the rise of companies like Goodrich and Goodyear tire continued to spur the rapid improvement of the technology, gradually leading to better materials, better machines, and more reliable compression molded products. Eventually this lead to compression molded products being reinforced with materials like glass fiber, paving the way towards the high-tech resins used in all sorts of materials today.

This method of manufacturing has become a wildly popular manufacturing technique because of the way it can quickly and cost efficiently mold large detailed parts without wasting material. This not only makes it ideal for businesses hoping to create a large volume of products (like rain boots) but it is also highly beneficial when a business is using expensive compounds that they can’t afford to waste. Compared to other molding techniques, compression molding is also capable of producing much larger shapes, making it a cheap and versatile technique for manufacturing many of the products we use every day, like rain boots and car parts.

From protective packaging and case inserts to protective padding and insoles for your footwear, compression molding can be found just about everywhere. So next time you pick up a plastic product you might otherwise take for granted – think about its history. How did it come to be? Was it the result of Leo Baekeland’s experiment so many years ago?

Post time: 06-02-2017