Liquid silicone injection molding
Liquid Silicone Rubber (LSR) Injection Molding
Liquid Silicone Rubber (LSR) Injection Molding is a specialized manufacturing process used to produce flexible, durable, and heat-resistant parts. Unlike traditional injection molding, which primarily uses thermoplastics, LSR injection molding is tailored for thermosetting materials like liquid silicone rubber. During molding, these materials undergo a permanent chemical cross-linking reaction, resulting in a solid, non-reversible structure.
LSR injection molding
LSR injection molding is widely applied across industries for manufacturing seals, medical devices, kitchenware, and overmolded electronics, valued for their high-temperature resistance, chemical stability, and consistent elasticity across a broad temperature range.
Why Choose ZUERST Silicone Injection Molding Services?
★ Fast Testing & Production: We offer rapid turnaround times, delivering prototypes in as little as 15 days. This speed is ideal for testing functionality and manufacturability before committing to mass production.
★ Expert Engineers:
★ State-of-the-Art Facilities: We utilize top-tier imported and domestic injection molds to deliver precise, high-quality molding efficiently, minimizing both time and costs.
★ Unlimited Capacity:
★ Cost-Effective Durability:
★ Rapid Global Delivery:
Liquid silicone injection molding offers the efficiency of traditional injection molding with the exceptional material properties of liquid silicone rubber. Here's why it's an excellent choice:
Applications of Liquid Silicone Injection Molding
Overmolding with Liquid Silicone
Overmolding is one of the most significant applications of liquid silicone injection molding, where flexible silicone is combined with rigid thermoplastic components. This process is particularly valuable for creating products that require both soft and hard materials, such as shock-absorbing skins for electronic devices, ergonomic grips for tools, and other applications where durability and comfort are essential.
The overmolding process typically involves two main techniques:
Double-Shot Molding: In this method, a thermoplastic part is first injected and cured within the mold. Afterward, liquid silicone is injected into the remaining space around the thermoplastic, where it bonds mechanically as it cures.
Insert Molding: This technique involves placing a pre-formed thermoplastic component into the mold, followed by injecting liquid silicone over it. The silicone conforms to the shape of the thermoplastic part, creating a strong mechanical bond through design features like undercuts or protrusions.
Since silicone does not chemically bond with most thermoplastics, achieving a secure connection relies on the physical interlocking of the materials. This is often accomplished by designing the substrate with features that allow the silicone to "lock" into place, ensuring the final product is both robust and durable.
Part Design Considerations for Liquid Silicone Injection Molding
When designing parts for liquid silicone injection molding, we approach it differently than we would for thermoplastics. Fortunately, silicone allows for greater flexibility in design, and we can take advantage of several unique properties.
Design Flexibility:
Ease of Removal: Because silicone is flexible, we don't have to worry as much about ejector pin placement. We can often lift the part manually from the mold, which also means we can be less strict with draft angles.
Variable Wall Thickness: Unlike thermoplastics, liquid silicone flows easily throughout the mold, even with inconsistent wall thicknesses. This allows us to design parts with thicker sections where necessary, without worrying about flow issues.
Handling Undercuts:
Protruding Sections: With silicone's soft and pliable nature, we have the opportunity to design parts with protruding undercuts. The material can be pulled out of the mold without the need for complex side actions, giving us more freedom in part geometry.
Flash Management:
Mitigating Flash: We must be mindful of silicone's tendency to cause flash due to its low viscosity. To minimize this, we focus on designing short parting lines and ensuring our tooling is tightly sealed to prevent any leakage.
Draft Angles:
Drafting Guidelines: For very shallow parts, we might not need any draft at all. However, for deeper parts, we typically apply one degree of draft per 2.5 cm to make demolding easier.
Gate Placement:
Strategic Gating: We prefer to place gates on the underside or in non-visible areas to maintain the part' s appearance and minimize any impact from flow marks.
Process-Specific Considerations:
Metering and Mixing: Since liquid silicone involves two components, with one containing a platinum catalyst, we carefully control the metering and mixing process to ensure a consistent and high-quality final product.
Temperature Control: Unlike thermoplastics, silicone starts as a liquid at room temperature and requires heat to cure. To avoid premature curing, we often use a cooled runner and sprue system, ensuring the material reaches the mold in optimal condition.
By understanding and leveraging the unique properties of liquid silicone, we can design parts that are both functional and manufacturable. This approach allows us to create high-quality, durable products that meet your specific needs, with the flexibility that silicone molding provides.