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The Compression Molding Machines and Mold Types

by Nice Rapid | Jul 01,2022 | Compression Molding

There is a rising popularity in the use of compression molding as a manufacturing technique and it is not surprising considering its benefits. However, part of its popularity is because it allows the use of advanced composites. The parts and products made from compression molding are stiffer, stronger, lighter, and more corrosion-resistant than metal parts.

Manufacturers are used to working with metals before but now they find compression molding materials easier to deal with. Most of them simply shifted from metals to compression molded parts.

Another advantage of compression molding is its ability to make highly complex parts. While it may not reach the production speed of injection molding quite yet, it offers more flexibility in creating complex geometries.

In addition, it allows longer fibers than injection molding, resulting in stiffer and stronger materials. It makes compression molding stand between injection molding and laminated compound fabrication.

With such capability of creating complex parts, it offers huge benefits to a wide variety of applications while keeping the cost and the turnaround time a priority.

At the heart of the success of compression molding are two important drivers: the compression molding machine and molds. In this article, we will get to know more about them to help you understand the process better.

compression molding products

Creating the Molds in Compression Molding

There are several mold options in compression molding and the choice will depend on the material or charge you will be using. The key to finding out the molds you need is whether they can withstand the compression molding process. If you will use heat, then you need a mold that can handle extreme temperature changes. Aside from temperature, it also has to withstand the amount of pressure during compression.

Here are the multiple ways to create molds for compression molding

Die Casting

One of the most popular manufacturing techniques in creating a mold for compression molding and other manufacturing requirements. It is the top choice because it delivers durable mold at a more affordable cost than other manufacturing methods. Die-casting often goes hand in hand with CNC machining as the dies in die casting are often made from the latter.

CNC Machining

Another option is creating the molds for compression molding is CNC machining. It is considered the optimal choice because the computerized part of the CNC machine allows engineers to control the design. However, it is an expensive means of tooling. Others go for a combination of die casting with CNC machining to create a more cost-effective mold.

3D Printing

Tooling for compression molding can also be made with 3D printing. This is ideal for smaller parts as 3D printing is the cheapest and fastest way of creating molds. You can make quick changes using the CAD software, have the design reprinted, and then tested. 3D printing usually applies to compression molds that will not be subjected to heat.

Common Types of Compression Molding Machines

Compression molding machines can vary in size from DIY creations to industrial machines. Like the parts they produce, compression molding machines are as diverse as the product designers and engineers creating them. Here are some examples.

Industrial Compression Molding Machines

Large industrial compression machines are best used in producing large commercial parts. It has a hydraulic system that makes it possible to achieve the required pressure to manufacture large and uniform parts as the worker can oversee the whole process from a separate control center.

Benchtop Presses

Smaller and mid-sized parts do not need industrial-sized compression molding machines. Instead, they need smaller benchtop compression machines. These devices take up less space than their industrial counterparts but can do large production runs as well. The multiple access points give engineers the flexibility to remove the flash and parts. Its smaller footprint can fit these machines in smaller warehouses and production facilities.

Cold or Heatless Compression Molding Machines

Compression molding can be done with or without heat. And it applies to compression molding machines of all sizes. There are even manufacturers who use cold compression molding and heat the raw materials before putting them on the mold. That means in compression molding, you can control the curing of the finished product and shorten the production cycles by introducing the heat at certain times.

Wet Compression Molding Machines

This type of compression molding machine is used when combining epoxies, resins, and other liquids with solid fabrics. This process is common for manufacturing durable car parts and components.

DIY Compression Molding Machines

Compression molding is a favorite tool by DIY’ers or at-home designers. They usually employ soft materials like urethane, and the rest can be easily molded using low pressure. You can even fabricate complex molds using CAD software and 3D printing.


Compression molding is a versatile process used by small and large manufacturing companies to create a wide variety of parts, from huge airplane parts to small nozzles. There are similar mold options available for use, but the choice always boils down to your project and the type of material you will use.

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