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Silicone Rubber Moulding

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Advanced Silicone Rubber Moulding Solutions: Precision, Durability, and Versatility in Modern Manufacturing

Silicone moulding is a versatile and essential process in modern manufacturing, offering a range of benefits for various applications. At Keaflex, we specialize in both Silicone Rubber (VMQ) and Liquid Silicone Rubber (LSR) moulding, providing solutions that meet diverse industrial needs. Our expertise extends to creating high-precision, durable moulds suited for everything from intricate component designs to large-scale production. This page offers an in-depth look at silicone moulding rubber, the applications it offers, a comparison between VMQ and LSR and our custom moulding capabilities.

Why Choose Silicone Over Other Rubber Moulding Materials?

Silicone rubber is particularly notable for its low viscosity, which makes it easy to work with in the moulding process, allowing for the creation of intricate shapes and fine details. This property, combined with its excellent tear strength and heat resistance, ensures that silicone moulded products are not only precise but also durable, capable of withstanding stretching, twisting, and high temperatures without damage.

In addition, silicone rubber’s biocompatibility makes it hypoallergenic and suitable for product with contact to human skin. Its resistance to bacterial growth and its non-staining, non-corroding nature make it ideal for various medical and consumer applications. Being tasteless and odourless, silicone can comply with FDA standards, making it perfect for food, beverage, and baby products like baby bottles and soothers.

In the diverse world of rubber moulding, silicone stands out due to its unique properties, but it’s important to consider how it compares to other rubber moulding materials. Materials like natural rubber, neoprene, nitrile, and EPDM each have their distinct advantages and specializations, making the choice of material crucial depending on the application’s specific requirements.

Comparing Silicone with Other Rubbers

Silicone rubber is known for its excellent temperature stability, chemical resistance, and electrical insulating properties, making it ideal for high-performance applications in harsh environments. Its heat resistant nature allows it to maintain stability and resist degradation under high temperatures, distinguishing it from many other rubbers. In contrast, materials like natural rubber offer superior abrasion resistance and tensile strength, suited for items like conveyor belts and shock absorbers. Neoprene stands out for its weathering and ozone resistance, commonly used in outdoor and automotive applications. Nitrile rubber, known for its resistance to oils and fuels, is often preferred for automotive gaskets and hoses. Lastly, EPDM excels in outdoor applications due to its resistance to weathering, ozone, and UV rays.

Understanding these differences is key to selecting the right material for your rubber moulding needs. Silicone might be the perfect choice for high-temperature applications or those requiring excellent flexibility and longevity, whereas other materials might be better suited for applications requiring higher physical strength or specific resistance properties.

Comparing Silicone Rubber (VMQ) and Liquid Silicone Rubber (LSR)

In the world of silicone moulding, understanding the distinct characteristics of Silicone Rubber (VMQ) and Liquid Silicone Rubber (LSR) is crucial for making informed decisions. These two materials, while similar in some aspects, have unique properties that make them suitable for different types of projects.

Characteristics of Silicone Rubber (VMQ)

Silicone Rubber, or VMQ, is renowned for its excellent temperature resistance, flexibility, and durability. It maintains its properties across a wide temperature range, making it ideal for applications subjected to extreme conditions. Silicone rubber is also appreciated for its flexibility, allowing it to be used in products that require a high degree of bendability and elasticity. Its durability ensures a long life for products even in demanding environments. Commonly, silicone rubber is chosen for outdoor applications, automotive parts, and kitchenware, where these characteristics are particularly beneficial.

Characteristics of Liquid Silicone Rubber (LSR)

Liquid Silicone Rubber, on the other hand, is distinguished by its exceptional fluidity and fast cure times, making it perfect for intricate and detailed casting moulds. LSR’s ability to fill complex and fine moulds quickly and efficiently is a key factor in its use for medical devices, infant care products, and precise electronic components. The material’s fast cure characteristic accelerates production cycles, thereby enhancing efficiency in manufacturing processes. Its biocompatibility and serializability make it a preferred choice in the healthcare and food industries.

When comparing VMQ and LSR, the decision often comes down to the specific requirements of the project, including casting requirements and the desired cure time. VMQ’s robustness and flexibility make it suitable for products that will be exposed to harsh conditions, while LSR’s precision and quick cure properties lend themselves to applications requiring intricate details and rapid production. Understanding the nuances between these two materials is key to selecting the right one for your moulding needs. Keaflex’s expertise lies in helping clients navigate these choices, ensuring the best material is selected for the performance, application, and specific requirements of each project.

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What Rubber Moulding Method is Used to Mould Silicone?

The rubber moulding method typically used for moulding silicone is called “Liquid Injection Moulding” (LIM). This process is specifically designed to handle liquid silicone rubber (LSR), which is a high-purity, platinum-cured version of silicone.

In some instances, particularly when striving for the highest quality in silicone parts, a vacuum chamber is employed during the material preparation phase. The use of a vacuum chamber helps to remove any air entrapped in the mixed silicone material, ensuring a more consistent and defect-free final product. This step is especially critical for applications demanding the highest levels of precision and quality in silicone rubber moulding.

Here’s an overview of the Liquid Injection Moulding process:

1. Material Preparation

Two-Part System: Liquid silicone rubber (LSR) is a two-component system, typically consisting of Part A and Part B. Each part usually contains a different catalyst.

Mixing: Before injection, these two parts are precisely mixed in a 1:1 ratio. The mixing must be thorough to ensure consistent curing and properties throughout the moulded part.

– Vacuum Chamber Degassing: After mixing, the silicone material may be placed in a vacuum chamber to remove any air bubbles, enhancing the quality of the final moulded part.

2. Injection

Moulding Machine: The LIM process uses a specialized injection moulding machine, often equipped with a dynamic mixing unit.

High-Pressure Injection: The mixed LSR is injected into a pre-heated mould at high pressure. This pressure ensures that the silicone fills the entire mould cavity and reaches all intricate areas.

3. Curing

Rapid Curing: Silicone rubber cures rapidly under heat. The high temperature in the mould accelerates the cross-linking of the silicone, transforming it from a liquid to a solid state.

Curing Time: The curing time for LSR is significantly shorter than that of traditional high-consistency rubber (HCR), which contributes to the efficiency of the process.

4. Ejection

Automated Ejection: After the silicone has cured, the mould opens, and the part is automatically ejected. Most LIM systems are designed for quick ejection and immediate continuation with the next cycle.

Minimal Post-Processing: Parts produced through LIM typically require little to no post-processing, such as trimming, as the process allows for precision and clean edges.

5. Cleaning and Preparation for the Next Cycle

Mould Maintenance: The mould is cleaned and inspected for any residues or defects to ensure the quality of subsequent parts.

Rapid Cycling: The LIM process is designed for rapid cycling, allowing for high-volume production runs with consistent quality.

For more information on silicone moulding and the services we provide, contact Keaflex today at 01420 473 645

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