At Rockeypad, one of the most frequent questions we receive from both current and potential customers revolves around our ability to insert mold pre-made compression molded inserts into our custom silicone keypads and components. While it might seem like an easy solution, we strongly advise against cross-contaminating different types of silicone rubber, especially when the rubber has been compression molded. The implications of this process can lead to bonding issues, product defects, and overall product failure.
Understanding Liquid Injection Molding (LIM)
At Rockeypad, we specialize in using 100% Liquid Injection Molding (LIM) for the production of silicone rubber products. LIM, as the name suggests, uses liquid silicone rubber (LSR), which is fundamentally different from high consistency rubber or gum stock used in other molding processes like compression molding. The liquid silicone rubber is a two-component system, with Part A and Part B. The key difference lies in the addition of a catalyst, typically platinum, which is present in only one of the two parts.
The LIM process is highly controlled and utilizes a “closed-loop system,” which means that the raw silicone is sealed from the moment it enters the machine until the final product is molded. This helps to minimize any chance of contamination and reduces the need for human intervention, further limiting the risk of cross-contamination. Additionally, the closed system reduces the handling of silicone, ensuring that it remains as pure and uncontaminated as possible throughout the molding process.
The Compression Molding Process
On the other hand, compression molding is one of the more common methods of silicone rubber molding, particularly in overseas production. This method, while simpler and more labor-intensive, operates in an open-air environment. Compression molding involves the use of pre-catalyzed silicone rubber, which is mixed with additives, such as powders, to enable curing when exposed to heat. Pigments are added by mixing the silicone using a two-roll mill, which introduces the potential for contamination due to the high amount of handling involved.
Once the silicone has been mixed with the necessary pigments and additives, it is weighed, reshaped, and placed into the mold cavity. The mold then closes, and the silicone is compressed between two heated mold halves, where it melts and vulcanizes to create the final part. This process is more susceptible to contamination because of the number of manual steps involved, as well as the exposure to air and heat.
The Issue with Cross-Contamination
One of the critical reasons we advise against using compression molded inserts in conjunction with LIM silicone rubber is the lack of a true cross-link bond between the two types of silicone. The additives used in compression molding prevent the formation of a robust chemical bond between the two materials. Without this proper bond, the silicone keypad or component is more prone to failure. The product may experience issues such as tears, inserts falling out, or improper bonding, which can result in functional and aesthetic defects.
When two types of silicone are not properly bonded, it compromises the durability and integrity of the final product. This can be especially problematic in applications where precision and reliability are essential, such as in medical, automotive, or consumer electronics components.
Best Practices for Successful Molding and Bonding
To avoid these issues, we strongly recommend that both the inserts and the overmolding be made from the same type of silicone material and by the same supplier. This ensures that the materials are fully compatible and that the bonding process occurs correctly. By using the same material, you can be confident that the silicone will bond properly to itself, ensuring a strong, durable connection between the insert and the molded silicone keypad or component.
At Rockeypad, we have more than 75 combined years of experience in liquid silicone injection molding and insert molding. Our team of experts is committed to producing high-quality silicone products that meet your exact specifications. We offer a wide range of silicone molding services, including custom silicone keypads, components, and inserts, all manufactured in-house to the highest industry standards.
Why Choose Rockeypad?
As a domestic manufacturer based in Newport News, Virginia, Rockeypad is equipped with the expertise, technology, and experience to deliver superior silicone molding solutions. Our team works closely with clients to ensure that every aspect of the product design, molding, and assembly process is carried out with precision and care. Whether you’re looking for custom silicone keypads, overmolding, or insert molding, we are here to provide the best possible solution for your needs.
By choosing Rockeypad, you are selecting a partner who understands the complexities of silicone molding and who is committed to delivering high-quality, reliable products. We work with you every step of the way to ensure that your product meets the highest standards of performance, aesthetics, and functionality.
Contact Rockeypad for More Information
If you have any questions about our molding capabilities or would like to learn more about our services, please don’t hesitate to reach out to us. You can visit our website at https://www.rockeypad.com to learn more about our silicone molding solutions or to request a quote. Our team is ready to assist you and provide the expert advice you need to make informed decisions for your silicone rubber products.
In conclusion, when it comes to custom silicone molding, using the correct type of silicone and molding method is crucial to ensuring product integrity and performance. At Rockeypad, we are committed to delivering the highest quality silicone components that meet your needs while maintaining the best industry practices. We look forward to working with you and helping bring your silicone projects to life.