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Everyone Should Know These Essential Facts About Liquid Silicone Rubber Molding

by Nice Rapid | Jul 28,2022 | Liquid Silicone Rubber Molding

There are many misconceptions floating around when it comes to silicone rubber. Most people believe things about liquid silicone rubber molding that aren't true. In this blog post, we'll set the record straight and give you the facts about silicone rubber molding. So, read on to learn more!

What is a Liquid Silicone Rubber?

A two-part silicone-based polymer, liquid silicone rubber (LSR), is joined by a chemical bond. It is most frequently used to produce injection molded components for goods used in sectors including consumer goods, automotives, food, appliances, and textiles.

The catalyst starts a cross-linking progression when the polymer is heated and injected. This advancement gives the substance enduring strength and shape following the curing process.

The resulting substance is robust and long-lasting, making it perfect for several products, such as:

  • Equipment hardware
  • auto components
  • interfaces in electronics
  • O-rings

LSR product

What is the Liquid Silicone Rubber (LSR) 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 creates higher injection pressure than the extruder barrel to keep the channel open.

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 the base silicone with the 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. The fluid silicone material begins to cure inside the heated mold in the meantime, it is heated in a mold, and when it has hardened, it ejects out. In some cases, silicone structures with complex geometries are removed manually. Contrary to thermoplastic operations, which involve heating plastic materials in the injection barrel and cooling them in the mold, this procedure uses the opposite of those two steps.

Additionally, the 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.

The Essential Facts About Liquid Silicone Rubber Molding

  • The LSR molding process encompasses many processes and materials, from the simple to the technically and dimensionally complex. This is due to the material's elasticity, which allows for undercuts and a variety of wall thickness combinations. The only limit that comes with liquid silicone is the designer's or engineer's imagination. As one of the most versatile materials, you can incorporate any design you want, from back-lit keys to chemical-resistant materials to custom colors.
  • Due to its quick cycle times, it is cost-effective, especially for high-volume outputs. Furthermore, no material waste or cost is associated with supporting operations like deflashing. The material is not only affordable but also helps you save money during the manufacturing process. It allows you to review the details before giving the final product your approval. Your business saves money because you can spot changes before the finished product is produced.
  • LSR molds require more time to construct, but this is due to the need for precise measurements, thousands of millimeters rather than hundreds. The process, however, is quick and stable if maintained adequately once it is up and running.
  • LSR is exceptional in maintaining its attributes up to 200°C while remaining elastic and flexible down to -50°C. In applications where insulation is necessary for user safety, such as encapsulated electronic components, cables, etc., LSR is beginning to be used more frequently. LSR also withstands chemical and ultraviolet (UV) exposure well.
  • LSR has long been used for bottles and pacifiers in the baby care industry. These days, LSR is used to create small medical devices with more elaborate designs and micro parts, surgical implants, wearables to monitor blood pressure or heart rate, and implantable devices.
  • One important quality of LSR is that it is biocompatible, resistant to bacteria, hydrophobic, odorless, and able to withstand repeated sterilization at high heat, all of which make the content suitable for use in healthcare applications.
  • For many products that need unique aesthetics, such as disposable razors or tool handles with a soft-touch grip, overmolding works incredibly well. A molder can accomplish this and cut down on the number of production steps by having the capacity to add adhesion to the material.
  • Significantly, LSR can be molded onto various materials, including metal, glass, and ceramics, which can bond. This improves manufacturing efficiency by lowering the number of individual components and reducing the assembly cost.
  • Due to its low viscosity, LSR is different from other materials because it needs to be processed with extreme precision. In terms of consistency, LSR is more like honey than polymer granules. During the molding cycle, it behaves differently from conventional polymers. The injection barrel is water-cooled to maintain LSR in its semi-liquid state before entering the mold. The substance is warmed and cured once it is inside the mold.


Nice Rapid offers a variety of liquid silicone rubber molding techniques to meet your specific requirements for your application. They are standalone products or can be over-molded to engineering plastics, metals, glass, and other materials.

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