Metal CNC Milling⏵
Expedited Injection Molding ⏵

Silicone Rubber Molding

Advantages & Benefits of Using Silicone Rubber Molding

Getting to market faster; quicker, better iterations and significantly lower project development costs are benefits that every RevPart customer enjoys. Our custom silicone molding prototyping services gives you the ability to receive quotes fast and rapidly make silicone parts and silicone prototypes.

In addition to the many benefits of using RevPart over other silicone prototype manufacturers, there are several key advantages to using a silicone injection molding process, including:


Flexible and Resilient

No taste or smell

Great durability


Efficient silicone molding process

Where do you find silicone parts?

Due to silicone’s unique set of properties it has become one of the most popular elastic materials and you can find examples of custom silicone molding across many industries. Here are some industries where silicone rubber injection molding is used:


Automotive Industry

Types of Silicone Rubber Molding

We offer two different types of custom silicone molding: LIM (Liquid Silicone Injection Molding) and compression molding. What makes these two types different is the technology, process and machine that is used to mold the parts. While both processes are great options your part geometry and complexity will likely determine which process to use. Here is some more information on each process:


LIM Silicone molding:

Also known as LSR silicone molding (Liquid Silicone Rubber), this is a liquid injection molding process, where a high-viscosity liquid comes in two parts, Part A and Part B is loaded into the molding machine. The machine mixes the two parts just before it is injected into the mold cavity, where a chemical reaction causes it to cure very quickly. After the part is cured the part is either ejected or manually pulled from the mold. Liquid Rubber Molding has some distinct benefits:


Compression molding:

The process involves placing a silicone rubber sheet onto a heated mold cavity. The rubber sheet is compressed between the two mold halves and fills to the mold cavity due to heat and pressure. The part is allowed to cool and is removed from the mold. Compression molding has some distinct benefits including lower molding and manufacturing costs. This makes compression molding the ideal choice for parts with low to medium complexity such as o-rings and sealing gaskets.


Differences Between LIM and Compression Molding

The big difference between the two is cost and shape complexity. The LIM process requires a silicone rubber mold that can withstand high pressures while a compression silicone mold has low pressures. This leads to higher costs for LIM silicone molds compared to an equivalent compression silicone mold. In addition to higher mold cost, LIM silicone typically has a higher processing cost than compression molding.

The major advantage to LIM silicone molding is that it can produce more complex shapes — and at tighter tolerances — than compression molding. What’s more, LIM is a closed process, so there’s less risk of end part contamination, which makes this process ideal for creating parts for the medical appliance and food industries.

Unsure of whether LIM or compression molding is the better fit for your application? Contact RevPart today and let our experts help you select the right molding method for you.


The Silicone Molding Process

Whether you’re using LIM silicone or compression silicone, both have a similar process. They both require building a mold, and both processes require running silicone material though the mold. As an experienced silicone prototype manufacturer, RevPart has in-depth knowledge of both processes. A good part starts with a good design and we can help you with that, including silicone rapid prototyping to test designs quickly and efficiently. Prototype silicone parts are a key component of our design and production services, and we combine these with our years of industry knowledge to ensure your production part comes out right the first time.


Building the liquid silicone rubber molding

Before making your silicone parts we first have to make the mold. Once you place your order our mold engineer begins designing the ideal mold for your part. Once the design is complete it moves into our mold building department. All RevPart silicone molds are built from high grade steel materials using CNC and EDM machines to create the mold cavities. Once the mold is complete we begin testing the mold and measuring all the dimensions to ensure it meets your specifications.


Making silicone parts

Your silicone rubber mold is moved into the production department and prepped for molding. The mold is placed into position on the molding machine and goes through an initial setup. Once setup is complete we are all ready to run parts. When dealing with a new mold we will go through FAI (First Article Inspection) process to ensure the parts are meeting your dimensional tolerances. Once the parts are approved we are all set to begin producing parts.

While we already mentioned that pigment can be added to the material to color it, there are several other value-added services as options. Contact RevPart to learn more about these value-added service options.


Silicone Molding FAQs

Find the answers to common liquid silicone rubber injection molding questions here.


Silicone molds are able to strongly resist and inhibit bacterial growth on the surface of the mold. Because of their material properties, silicone molds can also be easily and effectively cleaned and disinfected, quickly eliminating any dirt and microbes that may be present. Moreover, silicone molds are nonreactive with nearly all types of cleaning materials.

Silicone molding typically occurs through one of two types of methods: LIM silicone molding or compression molding. Both types offer relatively easy manufacturing, with a standard process of material injection into the mold cavity, a fill and hold period and a cooling period. LIM molding involves mixing a curing agent into the liquid base, allowing for faster hardening of the material. In both cases, silicone molding offers excellent throughput and efficiency for durable manufacturing with a broad range of complexity.

Silicone parts can offer a usable lifespan of up to 20 years under the right conditions. Fortunately, silicone is extremely forgiving, suitable for temperatures from -80 F to +450 F, with good resistance to damage or deformation from water, sunlight, ozone, acid and oxidation.

Silicone is a superior choice to plastic on several levels, including environmental reasons and human health considerations. Silicone is longer lasting than plastic and is intended for repeated, ongoing use, reducing the need for additional production and transportation resources. In addition, plastic is petroleum-based whereas silicone is not, reducing reliance on fossil fuels.