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The Complete Beginner's Guide to Silicone Rubber

by Nice Rapid | Jul 26,2022 | Liquid Silicone Rubber Molding

If you are new to manufacturing and are looking for an introduction to silicone rubber liquid molds, you have come to the right place.

This blog post will provide a comprehensive guide to everything you need to know about silicone rubber liquid molds. We will discuss what they are, how to use them, and some of their benefits. So, without further ado, let's get started!

The Properties of Silicone Rubber

Silicone rubber is a tough competitor for high-performance materials that can be used to create molds. However, it offers various distinctive advantages that have elevated the material's value across numerous industries.

Liquid silicone for molds is solid and transparent and has excellent electrical insulation qualities. In addition, it offers a variety of hardness levels for our silicone rubbers, from incredibly soft to medium. Therefore, simple to use when creating molds.

The use of liquid silicone rubber is incredibly diverse. For example, enabling you to apply silicone rubber to a model by pouring, brushing, or spraying it on there, allowing you to add details that other mold rubber cannot.

Products made of silicone are durable and non-reactive, making them ideal for many creative and unique applications.

Silicone water bottle

What are Silicone Rubber Elastomers?

A rubber-like substance called an elastomer is made of silicone that has been joined to another molecule. This additional substance could be carbon, hydrogen, or oxygen. And there are a ton of options available.

There are numerous applications for silicone rubber, depending on the additional chemical. Therefore, it's crucial to understand some of its distinctive characteristics. Natural rubber lacks structural integrity when comparing natural rubber to liquid silicone for mold production:

  • More heat-resistant
  • Significantly more stable from a chemical perspective,
  • Greater electrical insulation ability
  • More abrasion-resistant
  • Appropriate for outdoor use in all climates (and is even ozone resistant)

The Advantages of Liquid Silicone Rubber Mold

1. Heightened heat stability

LSRs can handle up to 180 °C without melting or creeping. As a result, they are now a well-liked alternative to seals and gaskets in heavy-duty and automotive applications.

2. Flexibility at low temperatures

Extreme temperatures can cause thermoplastic elastomers to become rigid. They become harder and more brittle as the temperature drops, eventually breaking. LSRs, on the other hand, are still malleable at -50 °C. They are an excellent option for any product that must function in a low-temperature setting.

3. Resistance to aging

When selecting the ideal material for your injection molding process, aging resistance is crucial. LSR materials that have been cured offer excellent resistance to UV rays, aging, and weathering. They are perfect for use in situations involving prolonged exposure.

4. Chemical defense

Chemical resistance is a property of thermoplastic elastomers in a variety of applications. However, they are only chemically resistant at moderate temperatures. Even at high temperatures, LSR exhibits low water absorption and excellent resistance to common chemicals.

5. Minimal compression set

Materials with a low compression set can withstand constant strain without permanently deforming. LSRs typically have a low compression setting, between 15% and 20%. Even after being compressed for a long time and exposed to various temperatures, they can maintain their elasticity.

6. Superior shelf-life dependability

One of the main elements influencing the ease of use in a manufacturing environment is the shelf life of liquid silicone rubber. Most LSR products have a shelf life of at least a year.

7. Electrical resistance

The materials being used by electronic manufacturers must be able to withstand corona discharge. LSR provides excellent electrical stress resistance without affecting the finished product's conductivity. Due to this, these materials are frequently utilized in electrical components and high-voltage applications.

The Liquid Silicone Rubber Molding Process

The material used most frequently in the liquid injection molding (LIM) process is liquid silicone rubber (LSR). This procedure uses a spring-loaded pin nozzle to stop materials from clogging the machine hardware. This spring-loaded mechanism generates higher injection pressure to keep the channel open than the extruder barrel.

Additionally, apportioned mixing of LSR is brought together using the pump system. Base-forming silicone with strengthening fibers and additives. A different plunger is used to hold base silicone with a catalyst. Each silicone substance will be pumped into a static mixer at a 1:1 ratio before the reaction to mix them starts.

The liquid mixture will then be injected into a mold that has been sealed and heated to between 180 and 200 degrees Celsius. In the meantime, the fluid silicone material begins to cure inside the heated mold, and when it has hardened, it ejects out. In some cases, silicone structures with complex geometries are removed manually. In thermoplastic operations, plastic materials are heated in the injection barrel and cooled in the mold. This process is the opposite of those operations.

Additionally, our engineering team uses computer-aided design (CAD) tools to improve the effectiveness of LSR injection molding. It can run simulations to find the ideal processing conditions and schedule, assess the outcomes, and examine integrated parts. Thermal imaging technology can also help engineers find production flaws, mold flaws, and design irregularities.


Custom silicone injection-molded parts' outstanding resistance to extreme heat, chemicals, ozone, and UV rays, as well as their high-quality color reproduction to accommodate various project designs, make them exceptionally durable.

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