Rubber Molding vs. Rubber Extruding: What Are the Differences?

Rubber is a very versatile material. It is used to manufacture a wide range of parts and products, from seals and gaskets to tubes and hoses to bumpers and grommets. As part of this, rubber can be subjected to a variety of manufacturing processes. Each process entails different techniques to turn the raw material into the desired component. 

Below, we focus on two of the most commonly-employed rubber manufacturing processes: rubber molding and rubber extruding. We highlight each of their steps, the advantages they offer, and the typical parts and products they produce in order to help readers understand which method is best suited for their needs.

What is Rubber Molding?

The rubber molding process encompasses three key components: 

• The custom-designed mold to make the desired part or product

• The raw material which is placed or injected into the mold

• The molding machine to hold the mold and place/inject the material

Together, these three elements enable rubber molding companies to manufacture various components in different shapes and sizes. 

Steps in the Rubber Molding Process

The steps in the rubber molding process are as follows: 

1. Creating the mold for the component
2. Installing the mold within the molding machine
3. Placing or injecting the material into the mold
4. Applying heat and pressure to cure (vulcanize) the material
5. Removing the finished component from the machine

These steps may vary slightly depending on the type of rubber molding method used for the project. The three most commonly utilized are: 

• Injection molding: rubber is injected at high pressures into a closed mold and then heated

• Compression molding: rubber is placed into a mold, which is then closed and subjected to heat and pressure

• Transfer molding: pre-formed rubber is inserted into a pot, forced through a runner and gate system into molding cavity, and then cured

Advantages of Rubber Molding

There are many advantages that rubber molding can bring to a production. For example, molding rubber products is one way to produce highly detailed three-dimensional shapes. Some of the other reasons manufacturers use it include: 

• It is fast. The rubber molding process offers fast cycle times, which helps reduce overall production time for projects. 

• It is efficient. Manufacturers can utilize the same molding machine to create a variety of parts and products by simply changing out the mold. As a result, rubber molding offers high machine efficiency rates. 

• It is economical. Rubber molding can be  amenable to automation, which enables manufacturers to lower operational costs. 

• It is precise and accurate. Molded rubber components can be made to a high degree of precision and accuracy, depending on the method and material. This allows manufacturers to achieve high dimensional tolerances and good surface finishes. 

Applications of Rubber Molding

Molded rubber parts and products find application in a wide range of industries. Typical components produced include: 

• Backflow preventers
• Elastomeric check valves
• Electrical enclosures
• Seal and gaskets
• Surgical instruments and devices

What is Rubber Extruding?

Similar to the rubber molding process, the rubber extrusion process relies on three key components: 

• The custom-designed die to make the desired part or product

• The raw material which is forced through the die

• The extrusion machine to hold the die and press the material through it

Together, these three elements allow rubber extrusion companies to create a wide range of parts and products in various shapes and sizes. 

Steps in the Rubber Extrusion Process

The rubber extrusion process involves forcing soft, unvulcanized rubber through a die with an opening in the profile/shape of the desired component, curing the formed material, and then cutting it to the proper length as a post molding process. The steps in the process are as follows: 

1. Raw material is loaded into the extruder’s feed hopper
2. The extruder’s heated shearing screw pushes the material forward into the die
3. The material is pushed through the die opening at high pressures and elevated temperatures
4. The material exits the die in the shape of the die opening
5. The material is vulcanized to ensure it maintains its shape
6. The material is cut to the proper length 

Advantages of Rubber Extrusion

Some of the key advantages of the rubber extrusion process are: 

• It is efficient. Minimal material waste is produced during rubber extrusion operations. As a result, rubber extrusion offers high material efficiency rates.

• It is economical. The production costs for rubber extrusion operations are much lower than many other production methods. 

• It is versatile. The rubber extrusion process can be used to create virtually any two-dimensional shape in continuous or set lengths. Additionally, the components produced can be durable, flexible, and lightweight, depending on their design and construction material.

Applications of Rubber Extrusion

Like the rubber molding process, the rubber extrusion process is utilized to produce components for many industries and applications. Typical parts and products include: 

• Connectors
• Gaskets
• Seals
• Trim
• Tubing
• Vibration reducers

Rubber Molding at Elastomer Technologies, Inc.

Rubber molding and rubber extrusion both play a critical role in the production of many rubber parts and products. 

Whether your next project requires rubber molding or rubber extrusion, it is important to partner with an experienced and knowledgeable part fabricator, as they are better equipped to ensure the success of your project. 

Looking for a rubber molding company you can rely on? Turn to the experts at Elastomer Technologies, Inc. We are an ISO 9001:2015 certified rubber molding company, and we have specialized in the design and manufacture of rubber molded parts and products for over 30 years. This extensive experience, knowledge, and skills enable us to deliver quality molded rubber solutions for nearly any part or product needs. 

To learn more about the differences between rubber molding and rubber extrusion or our services and capabilities, contact us or request a quote today.