Sourcing high-quality silicone parts for high-volume production runs is a common challenge for many medical device manufacturers. The initial cost of production-quality molds often makes smaller quantities financially impractical.
Seaway Plastics provides Liquid Silicone Rubber (LSR) Injection Molding solutions for medical devices and other components. We offer in-house tooling and engineering support to facilitate the manufacturing process. This approach enables us to produce precise and reliable silicone rubber parts in high volumes for demanding applications.
Read on to learn more about the specifics of LSR molding and its applications for medical parts.
What Is Silicone LSR Injection Molding?
LSR molding is a process for creating durable, flexible parts. It involves injecting liquid silicone rubber into a mold, which is then heated to cure and solidify the material into the desired shape. This method is highly automated and suitable for producing complex components with precision, especially in high-volume quantities where turnaround time is at a premium.
The molding process of liquid silicone rubber involves several steps:
- Material Preparation: Two liquid silicone components, a base and a catalyst, are pumped from separate containers and precisely mixed.
- Mold Injection: The blended LSR material is injected into a heated mold cavity until it is filled.
- Part Curing: Heat from the mold initiates a chemical reaction that solidifies, or cures, the liquid material into a stable rubber part.
- Part Ejection: Once the curing cycle is complete, the mold opens, and the finished silicone component is removed.
- Post-Processing: The part may undergo secondary operations such as trimming excess material, inspection, and packaging.
Medical Silicone Molding Applications and Requirements
Liquid Silicone Rubber (LSR) is widely used in medical molding because of its biocompatibility and flexibility. It can be molded into parts that are soft, durable, and resistant to heat or chemicals. These qualities make it suitable for items that need to meet strict medical standards.
It’s often chosen for components such as seals, valves, tubing, and wearable devices. Its ability to hold tight tolerances helps in producing consistent parts, even in small sizes. Medical applications also value LSR for its stability and for the way it can be sterilized without losing performance.
Why Choose LSR for Your High-Volume Production Needs?
Liquid silicone rubber (LSR) molding is an excellent choice for high-volume production because it combines efficiency, precision, and cost-effectiveness. The automated nature of the LSR injection molding process is ideal for manufacturing large quantities of parts with consistent quality and tight tolerances. The material’s ability to flow easily into complex molds ensures that even intricate designs can be reproduced accurately across large production runs.
High-volume production with LSR is highly efficient due to fast cycle times and minimal material waste, which helps to lower the overall cost per unit. The process is highly repeatable, ensuring that every part meets the same exacting standards. This makes LSR a practical and reliable option for mass production, allowing companies to bring thoroughly tested and finalized products to market at scale while maintaining high quality.
Comparing Resins for Medical Parts & Applications
Medical parts can be made with different processes, and each method offers unique strengths. The best option depends on the material, volume, and type of component you need:
| Method | Common Medical Materials | Sterilization Compatibility | Key Medical Applications | Ideal Volume Range |
| LSR Injection Molding | Medical-grade silicone (USP Class VI, ISO 10993) | Excellent (Autoclave, EtO, Gamma, Steam) | Seals, gaskets, catheters, patient contact devices, overmolded grips, surgical tubing | Low to High (100–100,000+) |
| Plastic Injection Molding | PEEK, Ultem, Polycarbonate, PSU, Medical PC | Good to Excellent (varies by material) | Housings, surgical instruments, connectors, high-strength components, and device cases | Medium to High (1,000–1M+) |
| CNC Machining | Titanium, Stainless Steel, PEEK, Delrin, Medical Aluminum | Excellent (most metals/ceramics) | Custom implants, surgical tools, high-precision prototypes, fixtures, one-offs | Very Low to Low (1–1,000) |
| Medical 3D Printing | Select biocompatible resins, Medical Nylon PA-12 | Limited (few FDA-cleared materials) | Surgical guides, anatomical models, custom jigs, and rapid prototypes | Very Low (1–100) |
ISO-13485 Certified Liquid Silicone Rubber (LSR) Injection Molding Company
At Seaway Plastics, we guide customers through the injection molding process. Our expertise is built on decades of successful work with more than 700 types of resins, including Liquid Silicone Rubber. Our engineers help pick the right machines and molding methods, and provide expert guidance on design for manufacturability concerns.
Injection molding with Seaway is a reliable and cost-effective method for producing parts. It allows complex shapes to be produced at high quality while keeping costs low. The process also works with many designs, finishes, and materials, making it one of the most flexible options for custom parts and assemblies.
Picking the right resin can be difficult because each material has different strengths and weaknesses. Seaway’s experience helps customers make the best choice for their project.
Here are some of the thermoplastics we work with:
- Nylon
- Acrylic
- Polyester
- Acetyl
- Polyurethane
- Polycarbonate
- Polyethylene
- Liquid crystal polymers
- And many others
Seaway offers many types of injection molding, including but not limited to:
- Low-Volume Injection Molding = 100 – 10,000 parts
- Mid-Volume Injection Molding = 10,000 – 500,000 parts
- High-Volume Injection Molding = ≥1,000,000 parts
- Two-shot molding
- Overmolding
- Silicone injection molding (LSR)
- Single-cavity, multi-cavity, and family molds
What Are the Alternatives to Two-Shot Molding?
Two-shot (non-LSR) molding is a popular choice, but it is not the only option. Other processes can be used when different designs, budgets, or production needs are required. Each method brings its own set of advantages depending on the project.
Overmolding is one alternative that combines silicone with another material in separate molding steps. This approach allows for strong bonds between components without needing a two-shot tool. It is often chosen when design flexibility is more important than cycle speed.
Insert molding is another option where silicone is molded around a pre-placed component. This method is commonly used when integrating metal or plastic inserts directly into the final part. It helps reduce assembly steps while keeping parts strong and functional.
Bonding methods can also be used when molding is not the best fit. For example, silicone parts can be joined to other materials using adhesives, mechanical fasteners, or thermal bonding. This provides flexibility for projects with lower volumes or unique design needs.
Partner With Seaway for Expert LSR Molding Solutions
Liquid Silicone Rubber (LSR) molding offers many benefits for medical and technical components. While two-shot molding is powerful, there are multiple paths to reach high-quality results.
At Seaway Plastics, we work closely with customers to understand their goals and help match them with the right molding solution. Our goal is to make the process simple, efficient, and aligned with your production needs.
Click below to learn more about how we can support your next injection molding project from concept to completion.