Clean Manufacturing With Liquid Silicone

Liquid silicone rubber injection molding, or LSR molding, is one of the most preferred methods for manufacturing precise and delicate components. This process is clean and highly accurate, produces high output, and offers superior strength and efficiency when integrated with the clean manufacturing technique of liquid injection molding.

This article will discuss the properties of LSR that make it suitable for liquid injection molding and the clean manufacturing process.

Characteristics of Liquid Silicone Rubber

Liquid silicone rubber is a high-purity platinum-cured silicone with physical, chemical, and thermal characteristics that make it ideal for products requiring excellent productivity, durability, and efficiency. In addition, LSR has the following properties:

Chemical Inertness

LSR’s silicone-oxygen structure has a higher bond strength than polyethylene or carbon-based materials. It is also resistant to oxidation, UV rays, water, ozone, and radiation damage. Because of its inertness, LSR is an excellent choice for food contact, medical applications, and silicone prototyping.

Hypoallergenic Property

LSR is naturally hypoallergenic and non-toxic and will not irritate or trigger allergic reactions in those with sensitive skin. Thus, it offers a safe and convenient remedy for respiratory products — such as oxygen and CPAP masks — and consumer items like earbuds, hearing aids, and portable monitoring devices worn for long periods.

Biocompatibility

The molecular structure of LSR also plays a role in its biocompatibility; it is odorless and tastes nothing. As a result, it is extensively used in baby products and other food and beverage-related goods because it adheres to the Food and Drug Administration (FDA) requirements.

Versatility

The mechanical and thermal stability characteristics of LSR are exceptional, resulting in it being preferred over other elastomeric polymers. In addition, it retains its properties at wide temperature ranges — high and low — varying from -40 ℃ to 200 ℃, depending on the grade.

Clean Manufacturing Process

The most consistent and stable materials utilized in the liquid silicone rubber injection molding process are platinum-cured polymerics. The vulcanization or curing process employs a two-part silicone compound (composed of A and B parts in different containers) attached to the pumping system and delivered to a static mixer at a predetermined ratio. Compound A is usually the base-forming material, whereas Compound B is a catalyst.

The mixture is combined with a platinum cure system before being injected into the mixing chamber. Next, it is added into the closed mold via a runner and gate system. Once cured, the components are removed from the mold cavities, and the process is repeated for the next batch.

Following that, the products may be subjected to post-molding, which includes the following processes:

• Deflashing: This method eliminates the residual rubber material used in injection molding. This is done via a centrifugal barrel finishing machine, a quick and cost-effective equipment to deflash multiple components.
• Post curing: This process is subject to high temperatures to accelerate curing and optimize some of the material’s physical parameters. This will also speed up the cross-linking process and ensure that the polymer molecules are correctly aligned.
• Inspecting: This process generates precise and prompt dimensional data and performance test results for molded parts.
• Packaging: This is the final step in preparing the molded parts for shipping after a thorough inspection.

Only the Best and Highest-Quality Molded Parts From Jefferson Rubber Works

Jefferson Rubber Works produces high-quality molded rubber parts and provides a wide range of rubber molding services, including liquid silicone injection molding, rubber-to-metal molding, compression molding, transfer molding, and more. We also offer a complete solution with part design, prototyping, production, finishing, and assembly — all with a quick turnaround and low cost!

Get in touch with us today to learn more about our capabilities or request a quote for your next project!