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Liquid Silicone Rubber Molding: What You need to Know

by Nice Rapid | Jun 21,2022 | Liquid Silicone Rubber Molding

One of the most popular industrial fabrications is silicone molding. The process, also known as liquid silicone rubber molding, molds a stock of material into various products and components. What makes it different from other injection molding processes is it relies on standard conventional mixing instead of pressurized mixing. It also concentrates on one material, liquid silicone rubber. This is an elastomer that is used to produce versatile items like seals, O-rings, electronic contacts, and many more.

What Makes Silicone an Ideal Material?

The most common material in liquid injection molding is acrylic and silicone rubber. For this discussion, we will concentrate more on the latter.

Compared with other thermoplastics, silicone offers great properties perfect for manufacturing parts with unique requirements. It has great stability and is resistant to extreme temperatures, hot or cold. The silicone material also exhibits tensile strength and flexibility.

It also exhibits a high degree of formability, allows coloring or transparency on the finished part, and depending on its chemical makeup, it can serve as an insulator or conductor.

The Liquid Injection Molding Process

The major area of concern in the liquid injection molding process is the mixing and dispensing of the material using a series of plungers. These plungers contain different materials, one plunger contains the base material, usually plastic that contains additives and fibers, while the other plunger has the catalyst that initiates the mixing process.

After combining these materials, they will be injected directly into the sealed mold. It will take some time to cure and after curing, it will be ejected from the silicone molding machine.

silicone utensils molds

Silicone Injection Molding in Rapid Prototyping

Silicone has a thermosetting property that needs intensive mixing. In creating products from silicone rubber, you select from either 3D printing, selective laser sintering, room temperature vulcanization (RTV), or injection molding.

The last option is highly preferred because it can use soft metal tooling to produce high-quality molder items. With this technique, producing prototypes has become faster because of rapid tooling. Silicone injection molding has many advantages including zero wastage since it is a direct injection process, zero burrs because it uses flashless technology, short cycle time, and high repeatability.

Applications of Silicone Molding Products

The material used in silicone molding belongs to the thermoset elastomer that has alternating silicon and oxygen atoms on its chemical structure. It can maintain its mechanical properties in the diverse temperature range.

Since it is extremely hydrophobic, items made from this material are great electrical insulators. You can make other items using silicone molding including seals, sealing membranes, multi-pin connectors, healthcare products, infant items, kitchenware, and many more.

Molding Considerations Worth Mentioning

When using this process, you have to take into account several considerations in its assembly and operations. You need to prevent leaks in the system as the molding compound can seep through the gaps in the machine. Seal and sealant materials are important components in the molding device. Something that you need to check all the time.

Another important step in maintaining the machine is proper maintenance and corrosion-resistant treatments. The inorganic fillers in the material compound can cause faster machine deterioration. To prevent this from happening, you need to increase maintenance work to offset the wear.

In manufacturing sensitive products like medical items through silicone molding, you can reduce the risk of contamination. You also need to pay attention to the mold flow analysis to improve efficiency and improve cooling and flow coverage.


We hope that you have learned the basics of the silicone molding process, the material, and considerations when you are using this technique. For more information, contact Nice Rapid.

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