RPM Industries LLC
rubber compression molding

Pros and Cons of Rubber Compression Molding

For the manufacturing of a simple rubber part or component, rubber compression molding is a proven method that people depend on. With this type of molding, a predetermined amount of rubber material is placed into a mold cavity, similar to how waffle mix is placed inside of a waffle maker. Once the cavity is closed, the rubber is heated and the material pressed into the desired rubber mold design based on the customer’s specifications.

Although this tried-and-true manufacturing method for rubber products offers numerous benefits, there are a few drawbacks that you should be aware of as well.


  • Inexpensive Tooling – The low cost of tooling is one of the advantages of compressed molding that everyone appreciates. Without a transfer cycle or injection process, there is not much infrastructure involved. Therefore, tooling costs are significantly less compared to other rubber manufacturing methods.
  • Ideal for Small Runs – Another benefit is that this method is ideal for small production runs. A lower capital cost for manufacturing a mold tool is the reason behind this.
  • Perfect for Larger Parts – Compression molding of rubber is also great for manufacturing larger parts and components. Due to the fact that the material loads directly into the mold cavity, there are no restrictions as to the weight of the finished product. The difference between compression molding vs injection molding is that with the latter, the barrel can only be filled to a certain volume, which limits the weight of the part of component manufactured.
  • No Runners, Gates, or Sprues – Another advantage of compressed molding is that no tooling features are required through which the material has to pass, including runners, gates, or sprues. As a result, less material is wasted, there are fewer cosmetic distractions, and the cost is reduced.


  • More Waste – Excess waste is probably the biggest issue with molding rubber using the compressed method. With this method, the mold cavity can be overfilled, which is sometimes necessary to achieve the correct pressure for curving a part or component.
  • Increased Labor Cost – The cost of labor is another consideration when it comes to compression molding vs injection molding. While the compression method is relatively simple, it is not a semi-automatic process as seen with injection molding. Therefore, more manpower is required, which pushes up labor cost.

At RPM Industries, Inc. we offer the experience and expertise to achieve the perfect rubber mold design based on your requirements. Call us today to speak with a team expert. We would love to have you as a valued customer.