We don’t just quote—we partner with you. Our engineering team proactively optimizes your design, eliminates hidden risks, and adds real value before production even begins.
Medical-Grade Silicone Technical Processing & Material Properties
We engineer liquid silicone rubber (LSR) components by meticulously optimizing the rheological behavior and thermal curing parameters to maximize chemical resistance and dynamic fatigue strength for demanding industrial applications. Utilizing IATF 16949-certified precision control, we execute advanced, flash-less overmolding onto custom stamped metal inserts, ensuring consistent dimensional stability and hermetic sealing across high-volume production cycles.
Cleanroom Molding: Dedicated ISO-certified sterile environments.
Micro-Tooling: Flash-less precision under 0.005mm.
Thermal Control: Closed-loop post-curing for stability.
Hybrid Integration: Seamless metal-to-LSR overmolding.
Request DFM Evaluation
Technical Handshake
Material Overview: Medical-Grade Liquid Silicone Rubber (LSR)
Medical-grade Liquid Silicone Rubber (LSR) is a highly specialized thermoset elastomer, widely recognized as a vital material in healthcare, life sciences, and advanced industrial manufacturing. By combining unparalleled biocompatibility with extreme temperature resistance and chemical inertness, the medical silicone injection molding material offers an exceptional balance of dynamic flexibility, tear strength, and absolute purity. It is particularly well-suited for high-precision, critical-use components that require strict sterilization compliance and reliable sealing performance, making it a preferred choice for complex overmolding applications and seamless integration with custom metal-stamped hardware.
Engineered Excellence
Absolute Biocompatibility
Inherently chemically inert and hypoallergenic, medical-grade silicone guarantees absolute purity. It seamlessly withstands rigorous, repeated sterilization protocols, including steam autoclaving and gamma radiation, without compromising its physical or chemical integrity.
Extreme Thermal Stability
Engineered to operate flawlessly across a drastic temperature spectrum, Liquid Silicone Rubber (LSR) maintains its critical elastomeric properties from extreme freezing environments up to high-heat applications, ensuring reliable performance in demanding healthcare settings.
Exceptional Tear Strength
The advanced cross-linked polymer matrix delivers superior elongation and dynamic fatigue resistance. This robust flexibility absorbs continuous mechanical stress, preventing tearing or structural failure in dynamic seals, valves, and wearable medical components.
Advanced Overmolding Synergy
With its exceptionally low viscosity before curing, liquid silicone effortlessly encapsulates intricate geometries. This allows for unparalleled precision in flash-less insert molding, establishing robust bonds directly onto custom metal-stamped hardware and rigid engineered plastic substrates.
Material Grade Variation
Healthcare Grade (Class VI)
Formulated for transient tissue contact and external medical devices requiring strict USP Class VI and ISO 10993 biocompatibility.Long-Term Implantable
Exceeds the highest purity and regulatory standards for permanent bodily implantation (>29 days) and critical life-sustaining applications.Self-Lubricating LSR
Incorporates specialized fluids that naturally exude to reduce surface friction, ideal for dynamic seals, O-rings, and moving mechanical assemblies.Optical Grade
Offers glass-like transparency, exceptional light transmission, and non-yellowing characteristics for surgical lighting, lenses, and medical optics.Fluorosilicone (FSR)
Engineered for highly aggressive environments, providing extreme degradation resistance to harsh chemical sterilization, solvents, and biological fluids.
Technical Specifications
Technical Data Section: Medical Silicone (LSR) Properties
To assist engineers in evaluating the baseline performance of medical-grade Liquid Silicone Rubber (LSR), the following table details core physical and mechanical metrics. These silicone injection molding properties are representative of standard platinum-cured, healthcare-grade elastomers commonly utilized in critical medical devices, fluid management systems, and biocompatible hardware integrations.
| PROPERTY | TEST METHOD (ASTM/ISO) | VALUE (METRIC) | VALUE (IMPERIAL) |
|---|---|---|---|
| Hardness (Shore A) | ASTM D2240 | 50 Shore A | 50 Shore A |
| Density / Specific Gravity | ASTM D792 | 1.12 g/cm³ | 0.040 lb/in³ |
| Tensile Strength | ASTM D412 | 9.5 MPa | 1375 psi |
| Elongation at Break | ASTM D412 | 500% | 500% |
| Tear Strength (Die B) | ASTM D624 | 40 kN/m | 228 ppi |
| Compression Set (22h @ 175°C) | ASTM D395 | < 20% | < 20% |
| Operating Temperature Range | - | -50°C to 250°C | -58°F to 482°F |
| Biocompatibility Rating | - | ISO 10993 / USP Class VI | ISO 10993 / USP Class VI |
Comparison Context: Medical LSR vs. Medical-Grade TPE
When specifying flexible elastomers for healthcare and high-precision assemblies, engineers frequently evaluate Liquid Silicone Rubber (LSR) against Thermoplastic Elastomers (TPE). While medical-grade TPE offers processing simplicity and cost-efficiency for single-use disposables, LSR delivers superior thermal stability, exceptional compression set resistance, and uncompromising biocompatibility. This makes LSR the definitive choice for critical seals, multi-use sterilizable instruments, and complex overmolded hardware components operating in extreme environments.
| PROPERTY / SPECIFICATION | MEDICAL LSR (THERMOSET) | MEDICAL TPE (THERMOPLASTIC) |
|---|---|---|
| Material Structure | Platinum-cured cross-linked polymer network | Phase-separated physical polymer blend |
| Temperature Resistance | -50°C to 250°C (Extreme stability across broad ranges) | -30°C to 120°C (Limited by thermoplastic melting point) |
| Sterilization Compatibility | Autoclave, Gamma, EtO, E-Beam (Withstands repeated cycles) | Gamma, EtO (High-heat autoclave may cause deformation) |
| Biocompatibility & Purity | Exceptional (Inherently inert, passes stringent USP Class VI) | Good (Heavily dependent on specific additives and compounding) |
| Compression Set Resistance | Excellent (Maintains structural memory and sealing integrity) | Fair to Good (Susceptible to permanent deformation under load) |
| Chemical Resistance | High resistance to harsh hospital-grade solvents and biological fluids | Moderate (Can degrade when exposed to aggressive lipid or solvent environments) |
| Processing Method | Liquid Injection Molding (Irreversible thermoset curing) | Standard Plastic Injection Molding (Melt and freeze cycle) |
| Overmolding Capabilities | Seamless flash-less bonding to precision stamped metals and high-temp plastics | Excellent mechanical and chemical bonding primarily to standard rigid plastics |
| Primary Applications | Implantables, multi-use surgical tools, O-rings, critical medical valves | Syringe plungers, soft-touch grips, wearable straps, disposable tubing |
| Cost-Efficiency | Premium (Higher raw material, tooling, and specialized processing costs) | Highly Economical (Faster cycle times, lower tooling costs, 100% recyclable) |
Technical Analysis
Advantages & Limitations: Medical Silicone Injection Molding
An objective, engineering-first analysis detailing the clinical strengths and inherent manufacturing challenges of Liquid Silicone Rubber (LSR) for high-precision healthcare components and advanced overmolding operations.
Key Advantages
Supreme Biocompatibility & Purity: Inherently hypoallergenic, chemically inert, and highly resistant to bacterial growth. Medical-grade LSR easily passes stringent ISO 10993 and USP Class VI testing, making it ideal for transient skin contact and critical implantable devices.
Exceptional Thermal Stability: LSR maintains its vital physical properties, flexibility, and structural memory across extreme temperature fluctuations (-50°C to 250°C), effortlessly outperforming traditional elastomers during repeated, high-heat sterilization cycles like steam autoclaving.
Advanced Overmolding Capabilities: The low pre-cure viscosity allows for seamless, flash-less overmolding directly onto custom precision-stamped metal inserts or rigid high-temp plastics, establishing robust, hermetically sealed bonds for complex multi-part medical assemblies.
Superior Compression Set Resistance: The platinum-cured, cross-linked thermoset structure delivers outstanding elastic memory. It strongly resists permanent deformation under continuous mechanical load, ensuring reliable, long-lasting performance for dynamic seals, O-rings, and fluid-control valves.
High Tear Strength & Flexibility: Engineered LSR formulations provide excellent elongation, tear resistance, and dynamic fatigue strength. This absorbs continuous mechanical stress, preventing structural failure in flexible surgical tools, respiratory masks, and wearable patient monitors.
Critical Limitations
Irreversible Thermoset Curing: Unlike thermoplastics, LSR undergoes a permanent chemical cross-linking process during molding. Once vulcanized, scrap runners and rejected parts cannot be melted down and reprocessed. Mitigation Tip: Implement strict flash-less tooling designs and cold-runner systems to drastically minimize material waste.
High Initial Tooling & Setup Costs: The ultra-low viscosity of liquid silicone requires exceptionally tight mold tolerances (often within 0.002mm), specialized vacuum systems, and precise multi-component pumping equipment to prevent flashing. Mitigation Tip: Leverage this tooling investment for high-volume, long-term production runs where the extended mold lifespan offsets initial capital expenditure.
Vulnerability to Cure Inhibition: Platinum-cured LSR is highly sensitive to cross-contamination. Exposure to trace amounts of amines, sulfur, or certain heavy metals found in standard plastics or rubbers will prevent the silicone from curing properly. Mitigation Tip: Mandate absolute segregation of LSR molding processes within dedicated, ISO-certified cleanroom environments.
Challenging Secondary Adhesion: Because silicone inherently resists bonding with other materials, post-mold operations like pad printing, painting, or applying standard adhesives are extremely difficult. Mitigation Tip: Integrate branding or texturing directly into the steel mold cavity, or utilize specialized plasma surface treatments if secondary adhesion is absolutely mandatory.
Cure-Time Dependency on Wall Thickness: While liquid injection molding generally features fast cycle times, the in-mold vulcanization phase increases significantly with thicker part geometries due to thermal transfer limitations. Mitigation Tip: Optimize Design for Manufacturability (DFM) by maintaining uniform, minimized wall thicknesses and utilizing strategic coring to accelerate cycle times.
Engineering Analysis: Medical Silicone Injection Molding Performance
A comprehensive breakdown of technical strengths, ideal use cases, and critical environmental constraints to guide your material selection process for precision mechanical components.
Clinical & Material Strengths
Core physical and chemical benefits that make this thermoset elastomer mandatory for strict medical manufacturing.The Sweet Spot
The specific scenarios where liquid silicone rubber significantly outperforms thermoplastic elastomers in reliability and patient safety.Manufacturing Constraints
Inherent processing characteristics that require stringent design-for-manufacturing (DFM) and strict cleanroom protocols.Avoidance Criteria
Specific operational environments or functional design requirements where standard medical silicone is likely to fail or add unnecessary cost.
Technical Process Manual
Injection Molding Processing Guide: Medical Silicone
To ensure consistent part quality, absolute biocompatibility, and repeatable tolerances across high-volume healthcare production, strictly adhere to these fundamental processing parameters for liquid thermoset elastomers.
Precision Mixing & Vacuum De-Airing
Unlike thermoplastics, medical-grade Liquid Silicone Rubber (LSR) does not require thermal drying. Instead, the two-part liquid thermoset demands absolute control during the metering phase. Achieving optimal vulcanization and eliminating microscopic voids requires an exact 1:1 static mixing ratio and stringent vacuum de-airing before the material enters the mold cavity.
Mix Ratio: Strict 1:1 (Part A to Part B)
Material Prep: Active Vacuum Degassing
Delivery System: Water-Cooled Cold Runner
Environment: Dedicated Cleanroom Processing
Engineer's Note
"Micro-bubbles trapped during the pumping phase do more than cause cosmetic defects; they create hidden structural voids that compromise the hermetic seal of critical medical devices. Furthermore, strict environmental isolation is mandatory—even trace exposure to sulfur or amines from standard plastics will instantly inhibit the platinum curing process, resulting in unvulcanized, sticky scrap."
Troubleshooting & Defect Mitigation: Medical Silicone (LSR)
Flash (Micro-Burrs)
Due to the ultra-low viscosity of liquid silicone before curing, the material can easily escape the mold cavity. To resolve this, immediately verify exact tool clamping pressure, inspect parting lines for microscopic wear, and ensure your tooling utilizes a strict flash-less design.Air Entrapment (Voids & Bubbles)
Trapped air compromises the mechanical strength and sterile integrity of critical medical devices. To mitigate this, verify the performance of your vacuum de-airing system during the pumping stage, optimize mold venting locations, and adjust injection speeds to allow uniform cavity filling.Platinum Cure Inhibition (Sticky Parts)
Exposure to trace contaminants like sulfur, latex, or amines instantly prevents the silicone from fully cross-linking, resulting in unvulcanized, sticky components. To correct this, isolate the LSR molding environment, deeply clean the mold surfaces, and enforce strict cleanroom material handling protocols.
Critical Dos & Don'ts
Engineering pro-tips and specific processing protocols to protect material performance, mold longevity and operator safety
Prevent Premature Vulcanization (Scorching): Strictly maintain chilled temperatures throughout the cold-runner delivery system. Never allow the precisely mixed, reactive liquid silicone to exceed safe temperature thresholds before entering the heated mold cavity, which causes irreversible premature curing and clogs the nozzle.
Mandate Absolute Cleanroom Isolation: Never expose the platinum-cured LSR process to standard industrial environments. Even microscopic trace amounts of sulfur, amines, or latex cross-contamination will instantly inhibit the chemical catalyst, resulting in sticky, unvulcanized, and totally compromised medical parts.
Enforce Micro-Venting & Vacuum Systems: Always utilize highly specialized vacuum-assisted micro-venting (typically under 0.005 mm). Because medical silicone features an ultra-low pre-cure viscosity, applying standard thermoplastic vent sizes will cause catastrophic flashing and ruin critical sealing surfaces.
Why Choose Us
Why Industry Leaders Choose Kravzik?
Delivering uncompromising precision, accelerated speed-to-market, and fully integrated manufacturing solutions for the most demanding technical applications.
Accelerated NPI & Rapid Turnaround
We compress your development cycles. By integrating agile manufacturing processes with advanced in-house capabilities, we deliver functional, test-ready components in days—helping you hit tight launch deadlines without sacrificing quality.
Production-Grade Precision & QA
Quality is non-negotiable for medical, aviation, and advanced robotics applications. We achieve strict dimensional tolerances backed by comprehensive in-house metrology, including CMM vision systems, complete FAI reporting, and ISO-compliant workflows.
Proactive DFM & Cost Optimization
We don’t just execute prints; we optimize them. Our engineering team provides rigorous Design for Manufacturability (DFM) reviews upfront. By identifying potential defects early, we significantly reduce tooling risks and overall unit costs.
Seamless Scalability & IP Protection
Grow your volume seamlessly without switching suppliers. We transition your projects from low-volume prototypes to high-yield mass production under one roof. All proprietary CAD designs are strictly protected under legally binding NDAs.
TECHNICAL DATA LIBRARY
Evaluate High-Performance Elastomers & Silicones Specifications
Liquid Silicone Rubber (LSR)
Precision LSR molding for medical and automotive seals. IATF 16949 certified platinum-cure processing ensures zero-defect, high-performance elastomeric parts with superior thermal stability.
TPU
Industrial-grade TPU molding specializing in high-rebound elastomers and precision overmolding. We deliver ISO-certified components with unmatched abrasion resistance and dynamic flexibility for mission-critical applications.
Request DFM EvaluationAccess Full Material Data Sheets
TECHNICAL REFERENCE
Frequently Asked Questions
Answers to common questions regarding precision, tooling, materials, and our integrated molding capabilities.
Absolutely. We strictly utilize medical-grade platinum-cured silicone elastomers that fully comply with ISO 10993 and USP Class VI biocompatibility standards. Our entire manufacturing process takes place within dedicated, ISO-certified cleanroom environments to guarantee absolute purity, making our components completely safe for transient skin contact, fluid management, and surgical applications.
Yes, this is a core Kravzik engineering advantage. Because we operate robust in-house precision metal stamping alongside our injection molding lines, we can seamlessly overmold liquid silicone directly onto custom stainless steel or brass inserts. This single-source approach creates a hermetically sealed, multi-material component while completely eliminating multi-vendor tolerance stacking and assembly risks.
Liquid silicone has an exceptionally low pre-cure viscosity, meaning standard plastic molds will leak and cause micro-burrs. We engineer highly specialized, flash-less micro-tooling with tolerances held under 0.005 mm and integrate active vacuum de-airing systems. This eliminates the need for manual secondary trimming, ensuring your critical sealing surfaces are pristine directly out of the mold.
No. Medical-grade LSR features extraordinary thermal stability, effortlessly maintaining its structural integrity, flexibility, and elastic memory across a massive temperature range from -50°C up to 250°C. Your overmolded surgical instruments and reusable medical devices will easily survive thousands of rigorous, high-heat steam autoclave and gamma radiation cycles without yellowing, cracking, or degrading.
LSR requires dedicated cold-runner delivery systems, specialized vacuum seals, and ultra-tight machining tolerances to prevent the low-viscosity liquid from flashing. While the initial capital expenditure is higher, Kravzik engineers these high-precision steel molds for extreme longevity. For high-volume medical production, this translates to faster cycle times, zero material waste from runners, and a highly competitive lower cost per unit over the product’s lifecycle.
Platinum-cured silicone is highly sensitive and will refuse to vulcanize if exposed to trace contaminants like sulfur, amines, or certain standard plastics. We mitigate this catastrophic risk by strictly isolating our liquid silicone injection machines within dedicated cleanrooms. We enforce rigid material handling protocols and deep-clean all mold surfaces to guarantee perfect cross-linking and consistent part quality.
While LSR is significantly more forgiving than rigid plastics regarding sink marks and warpage, uniform wall thickness is still highly recommended. In liquid injection molding, the vulcanization cure time is dictated by the thickest cross-section of the part. By optimizing your design for uniform thickness, we can drastically reduce in-mold curing times, accelerating your production schedule and lowering manufacturing costs.
Yes. We help you navigate the entire product lifecycle from initial design-for-manufacturing verification to full-scale commercialization. We can develop single-cavity prototype tooling to rigorously test the silicone formulation, overmolding adhesion, and clinical functionality. Once validated, Kravzik seamlessly transitions your project into high-cavitation, high-volume automated production runs without compromising precision or medical compliance.
Still have questions?
Our engineering team loves solving complex problems. Chat with us or send your drawing for a review.
Request DFM Evaluation