What is Molded Rubber?

When it comes to rubber manufacturing, molding is one of the most common methods. But what exactly is molded rubber, and why is it so widely used?

Molded rubber is rubber that has been shaped into a specific form using a molding process. This method is ideal for producing custom parts with precise dimensions and intricate shapes, often used in industries like automotive, medical, and aerospace.

Let’s explore some of the key questions about molded rubber, including its moldability and how it compares to silicone molding.

Is Silicone Rubber Moldable?

Silicone rubber¹ is known for its flexibility and heat resistance, but is it moldable? Let’s take a closer look at how silicone rubber can be molded.

Yes, silicone rubber is highly moldable. It’s often used in molding processes due to its excellent properties, such as high temperature resistance, flexibility, and durability, making it ideal for various applications.

Silicone rubber is one of the most moldable types of rubber, thanks to its low viscosity and ability to retain its shape once cured. It is especially useful for creating precise, intricate parts, which is why it’s favored in medical devices, cooking tools, and other high-precision products.

Benefits of Molding Silicone Rubber

• Temperature Resistance: Silicone rubber can withstand extreme temperatures, making it ideal for automotive and aerospace applications.
• Flexibility: Silicone’s flexibility allows it to be molded into complex shapes with intricate details.

What Silicones Can Be Molded?

Silicone rubber is versatile, but not all types of silicone are the same. What makes certain silicones better for molding than others?

Several types of silicone can be molded, with Liquid Silicone Rubber (LSR) and High Consistency Rubber (HCR) being the most popular. These types offer unique properties suited to different molding applications.

Different formulations of silicone rubber can be molded depending on the application, each offering specific benefits. Let’s look into these types in more detail:

Liquid Silicone Rubber (LSR)

LSR is known for its ability to be injected into molds with high precision. This type of silicone rubber is often used for creating medical devices, baby products, and parts requiring intricate detail. It also offers excellent chemical stability and flexibility.

High Consistency Rubber (HCR)

HCR is used for more robust applications, where strength and durability are required. It is often used in automotive parts and industrial applications. HCR can be molded through compression molding, and it retains its shape even under pressure and extreme temperatures.

Other Types of Silicone Rubber

There are also specialty silicones designed for specific applications, such as food-grade silicones, which are safe for use in kitchen products, or flame-retardant silicones, which are used in electrical components.

Is Rubber Mould Better Than Silicone Mould?

Both rubber and silicone have their benefits when it comes to molding. But which one is better for your application? Let's compare the two.

Whether rubber or silicone molding is better depends on the specific requirements of the application. Silicone molding is more heat-resistant and flexible, while rubber molding offers more durability and cost-effectiveness in certain cases.

Choosing between rubber and silicone molds depends on factors like temperature resistance, flexibility, cost, and application. Here’s a breakdown:

Silicone Molding Advantages

• High Temperature Resistance: Silicone can withstand extreme temperatures, making it ideal for automotive and medical applications.
• Flexibility and Precision: Silicone molds are perfect for intricate designs and parts that require flexibility, such as seals and gaskets.
• Biocompatibility: Silicone is non-reactive and is often used in medical and food-grade applications.

Rubber Molding Advantages

• Durability: Rubber is tougher and more resistant to wear, making it ideal for parts exposed to constant friction.
• Cost-Effective: Rubber molding tends to be more cost-effective, especially for large-volume production runs.
• Elasticity: Rubber offers excellent elasticity, making it ideal for seals and vibration-damping parts.

How Do You Make Moulded Rubber?

Molded rubber² is a versatile product that requires specific processes to ensure quality and precision. So, how exactly is molded rubber made?

Molded rubber is typically created through processes like compression molding, injection molding, or transfer molding, depending on the desired shape and material properties.

The process of making molded rubber involves several key steps, each of which ensures the final product is accurate, durable, and meets performance specifications.

Compression Molding¹

In compression molding, rubber is placed into a heated mold, and pressure is applied to shape it. This is one of the most common methods for producing rubber gaskets, seals, and other simple parts. The mold is then opened, and the part is removed.

Injection Molding²

Injection molding involves injecting rubber into a mold cavity under pressure. This process is used for more complex parts with fine details. It’s ideal for high-volume production and ensures precision in the final product.

Transfer Molding³

Transfer molding is a hybrid between compression molding and injection molding. It involves transferring rubber from a heated chamber into a mold cavity under pressure. This process is suitable for parts requiring high precision and intricate shapes.

Molded Rubber Tolerance Table

Conclusion

Molded rubber is essential in many industries, from automotive to medical. Whether using rubber or silicone, understanding the molding processes and the materials involved is key to ensuring the right fit for your application.