Types of Molds Used to Produce Silicone Rubber Parts

Silicone rubber parts

Types of Molds Used to Produce Silicone Rubber Parts

Silicone rubber is known for its high resistance to extreme temperatures and outdoor exposure. It is used in many applications from automotive components and electrical parts to medical devices including ear plugs and respirators.

These products require processing that can produce accurate molded parts. WayKen utilizes modern rapid prototyping technologies to create accurate master patterns and silicone rubber moulds.

Liquid Silicone Rubber (LSR)

Liquid Silicone Rubber (LSR) is a thermoset material that offers superior strength, long life and resistance to extreme temperature and chemical exposure. It is a very versatile material that can enhance the Silicone rubber parts design options of small features, thin components and high-precision items. LSR is also an ideal choice for molding medical components and seals due to its biocompatible and hypoallergenic characteristics.

LSR is a two-component system that consists of component A and component B, which are mixed in a one-to-one ratio through a metering unit before being injected into the mold cavity to be cured. This process is faster than traditional injection molding methods, with cycle times averaging 30 seconds. This means that a finished silicone part can be produced more quickly than an organic or peroxide-cured silicone product.

After injection, the molded piece is clamped together and any remaining liquid is removed. The product is then trimmed, washed and inspected to ensure the quality of the finished part. Once complete, the product can be shipped to its final destination.

Stockwell maintains a large inventory of LSR in different grades and durometers to meet the needs of a variety of industries. Contact us for more information about how we can help with your project. We offer low-cost AL molds and can produce prototypes or end-use production parts in 15 days or less.

Compression Molding

Compression molding is a production method for thermosetting polymers, elastomers and composites. It can also be used for a limited range of thermoplastics. The process uses both pressure and temperature to achieve the desired result. The mold, or metal tool, is heated and fitted to the desired shape of the final product. The fiber reinforced resin material, known as the charge, is then inserted into the mold and compressed. The time it takes for the compression to take place can vary and will depend on factors like the thickness of the polymer and the amount of heat applied.

Once the part has been molded, the pressure is released and any excess resin is removed from around the edges of the finished product. The mold is then cleaned and the product is ready for shipping or assembly. Compression molding can be used to produce complex shapes, as well as ribs and inserts. This reduces or eliminates the need for secondary processes, saving both cost and lead times.

For example, a rubber compression mold could be used to make a seal that is required to maintain its physical properties over a wide temperature range. Silicone rubber is a good choice for this application because it has high temperature resistance and can be molded into intricate patterns. In addition, it is easy to sand and polish the surface of a compression molded part, which improves its aesthetics and functionality.

Transfer Molding

Transfer molding is an alternative to injection molding that is often used for smaller, less complex silicone rubber products. Similar to compression molding, a pre-measured amount of unvulcanized rubber is loaded into a pot (or “well”) that is then closed and pressed down by a piston that forces the material into the mold’s shape via a small sprue hole. Once the mold is closed and cured, any excess material in the pot or sprue well is trimmed off before the product is shipped.

Another variation on the standard resin transfer process is vacuum-assisted resin transfer molding (VARTM). This involves adding reinforcing fibers such as glass, carbon, or Kevlar into the mold before injecting the liquid polymer, which then saturates the material for a strong and durable final product.

In both cases, the end result is a high-quality, molded silicone rubber part that can withstand many years of wear and tear in any application. If you are considering using this type of custom molding service to create a new product, the team at The Rubber Group can recommend the best production method for your needs. The right choice will depend on the complexity of your design, desired production volume, and cost considerations. Contact us to learn more about all three types of rubber molding processes and how they can benefit your unique project.

Injection Molding

Injection molding is a fast and cost-effective way to produce high volumes of plastic parts. It is most commonly used for automotive and electronics components. It works by injecting melted plastic into a mold using a long, cylindrical heated barrel. A large injection screw sits in the middle of this Silicone Rubber Parts – Supplier barrel, and a choice of mold tool is attached to the end of it.

This process produces accurate parts that do not require much finishing. Most molded parts have a smooth surface but can also be textured or engraved. Injection molded parts often contain bosses, or cylindrical projections that are designed for assembly and attachment (in conjunction with self-tapping screws or threaded inserts).

The injection molding process uses thermoset plastics. There are more than 85,000 commercial plastic material options and 45 polymer families that can be used for injection molding. The most common types of resins used for injection molding are polyethylene and ABS plastic.

An experienced custom injection molding partner offers manufacturers a decided advantage in terms of efficiency. They have decades of experience that they can draw on, and they use advanced injection molding machine technology to streamline production processes and ensure accuracy and quality. Their focus on design for manufacturability eliminates problems and costly redos, and incorporating value-added services minimizes production delays. They can also help you select the best resin for your project and create a realistic timeline based on their experience.

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