Silicone Rubber Molding
We are pleased to work with medical device OEM engineers, as well as creative product developers who require the unique physical properties of silicone rubber.
Casco Bay Molding offers the advantage of highly experienced team of Plastic and Silicone engineers with years of tooling, part design and production know-how. Below please find several approaches that we pursue based on customer needs:
High Volume: Cold Runner Molds: Casco Bay Molding offers cold runner silicone injection molding solutions to our Class VI, healthcare grade Liquid Silicone Rubber part customers. This approach is generally used for our higher volume customer applications where the silicone rubber cost is a large part of the overall production cost. We employ removal robots and special mold designs to fully automate machine run-time for silicone parts.
Low Volume: Short Run Silicone Molding and Part Production requires a tool steel core and cavity designed to fit into a Casco Bay Molding mold base. Liquid Silicone Rubber core and cavity sets are fabricated under our direction. CBM is able to make silicone part and mold design changes with an efficient turnaround time, shortening our customer’s product development cycle. Generally these parts are manually extracted so that unit part volume increases enough to justify a higher volume approach.
Prototype Silicone Molding: Our prototype liquid silicone rubber parts are also produced on steel core and cavity (C&C) sets. Yes, Aluminum C&C sets can save a couple hundred dollars, but our experience shows that this cost is negligible compared to the cost of re-cutting a C&C set once the aluminum becomes warped after repeated thermal cycling. We aim to turn simple core & cavity sets around in 3 to 8 weeks depending on our production schedule. Occasionally, our prototype steel core and cavity sets can be hand injected but are generally fit into one of our standard tool steel LSR mold bases. Frequently, we quote tooling fees and mold test fees for small volume jobs requiring LSR parts.
Chinese Liquid Silicone Rubber Molds: We do not find Chinese/Asian molds a viable option for LSR molds or core and cavity sets. The tighter LSR tooling tolerances and ability to adjust the LSR tool’s vents, gates and/or part geometry negate the cost advantage. In our opinion, Plastic molds can offer some pricing advantages as long as a US tool-making partner stands behind the mold.
Liquid Silicone Rubber 2-Component Parts or Over-molded Parts: As described, we have experience with 2-component parts or over-molding silicone onto various plastic or metal parts. Per standard LSR parts, we start with a core & cavity set and evolve the project into a full blown silicone injection mold as the project dictates.
Note: It is important we understand how a part will be used and it’s critical dimensions. Locating gates and vents in non-critical part regions facilitates good mold cavity filling while allowing for proper shrinkage in areas of critical dimensions.
Casco Bay Molding has an excellent working history with our outside mold fabricators, who are frequently involved in a final part review before production. Our ISO Certified team / customer approach to product development is based on understanding the important aspects of the silicone component’s function within the final application. We would be pleased to have a part and mold design review meeting prior to beginning a project.
