In the world of parts manufacturing, there are many methods used to mass produce parts for items that people use every day. Some of those processes include structural foam molding, reaction injection molding and polyurethane injection molding or plastic injection molding.

Let’s take a more in-depth look at a few of those processes:


Structural foam molding works by adding inert gas to a melted polymer. That polymer is injected into an injection molding tool through sprue bushings and nozzles. A skin forms against the mold as the tool cools and the action produced through foaming creates a honeycomb structure that reduces shrinkage once molding is finished.


With structural foam molding, parts produced are significantly lighter and there are many other advantages. It cuts down on stress and warpage of parts, it give parts a good strength-to-weight ratio, it can be used as a suitable replacement for many types of traditional building materials and is very impact resistant.


Another way of manufacturing parts is done through plastic injection molding. This works with the injection of molten materials into a mold through sprue bushings and nozzles and can be done with many different kinds of materials. Take die-casting for example, which is done by using molten metal in this process. Materials are later put into a heated barrel and then forced into a mold cavity, which hardens as it cools.

When it comes to plastic injection molding, there are a lot of parts such as sprue bushings, machine nozzles, dual stage filters and valve gate systems. What’s also important is the right kind of machine. Nearly a million Americans work in plastics manufacturing and having the right molding machine makes their jobs a lot easier along with all the right parts, whether it’s nozzles, valves or sprue bushings.

When it comes to picking the right molding machine, you want to make sure to choose the right series for starters. Different molders have been created for different industries and you want to make sure the one you’re working with is best for your specific processes.

You also want to make sure the machine allows products to be taken out. Machining can be a lot of hard work and you want to make sure the finished products can be easily ejected.

The right machine also allows for full injection of all the materials needed for molding and also allows for fast injection. Materials need to be injected at the right speed to get the quality finish that’s needed.


Reaction injection molding (RIM) involves plastics as well, but this process sees the mixing of two liquids which are then injected into a mold where they can chemically react. RIM allows for manufactures to shape details into their parts and mold plastic into the intricate shapes that are needed. This works because molds are subjected to high pressure and the plastic inside the mold being pressed harder into it.

RIM also allows for great strength of parts by adding fillers into the injection molds. This increases the density of the plastic being used and makes parts stronger and longer-lasting. RIM also allows different plastics to be used simultaneously, so companies can manufacture parts without having to stick to just one kind of plastic. Another advantage of RIM is that it also companies to work more efficiently since the molding process is quick and allows many parts to be created from just a single mold. This saves companies a lot of time and money.


Each time of molding has its advantages and knowing the differences and benefits of each of them along with having the right tools will help your company save time and money while increasing efficiency and producing high-quality parts.