{"id":2340,"date":"2026-07-04T17:16:50","date_gmt":"2026-07-04T17:16:50","guid":{"rendered":"https:\/\/www.fhysilicone.com\/?p=2340"},"modified":"2026-07-04T17:16:54","modified_gmt":"2026-07-04T17:16:54","slug":"lsr-overmolding-in-medical-devices","status":"publish","type":"post","link":"https:\/\/www.fhysilicone.com\/fi\/lsr-overmolding-in-medical-devices\/","title":{"rendered":"LSR-p\u00e4\u00e4llystys l\u00e4\u00e4kinn\u00e4llisiss\u00e4 laitteissa: mit\u00e4 insin\u00f6\u00f6rien on syyt\u00e4 tiet\u00e4\u00e4"},"content":{"rendered":"<h2 class=\"wp-block-heading\">1. Johdanto<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Liquid Silicone Rubber (LSR) overmolding has become one of the most important manufacturing technologies in modern medical device engineering. It enables the combination of <strong>rigid substrates (plastic or metal)<\/strong> with <strong>soft silicone sealing or functional layers<\/strong>, creating components that meet strict requirements for biocompatibility, sealing performance, and long-term durability.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">K\u00e4ytt\u00f6kohteita ovat muun muassa:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Catheter connectors<\/li>\n\n\n\n<li>Sealing diaphragms<\/li>\n\n\n\n<li>Respiratory device interfaces<\/li>\n\n\n\n<li>Drug delivery systems<\/li>\n\n\n\n<li>Surgical instrument components<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">For engineers, understanding LSR overmolding is essential for designing reliable, scalable medical devices.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img fetchpriority=\"high\" decoding=\"async\" width=\"1024\" height=\"819\" src=\"https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/LSR-Overmolding-in-Medical-Devices-What-Engineers-Need-to-Know-1024x819.png\" alt=\"\" class=\"wp-image-2341\" srcset=\"https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/LSR-Overmolding-in-Medical-Devices-What-Engineers-Need-to-Know-1024x819.png 1024w, https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/LSR-Overmolding-in-Medical-Devices-What-Engineers-Need-to-Know-300x240.png 300w, https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/LSR-Overmolding-in-Medical-Devices-What-Engineers-Need-to-Know-768x615.png 768w, https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/LSR-Overmolding-in-Medical-Devices-What-Engineers-Need-to-Know-15x12.png 15w, https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/LSR-Overmolding-in-Medical-Devices-What-Engineers-Need-to-Know-600x480.png 600w, https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/LSR-Overmolding-in-Medical-Devices-What-Engineers-Need-to-Know.png 1402w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">2. What Is LSR Overmolding?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">LSR overmolding is a manufacturing process where <strong>liquid silicone rubber is injected onto a pre-formed substrate<\/strong> such as:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Polycarbonate (PC)<\/li>\n\n\n\n<li>Polyamide (PA)<\/li>\n\n\n\n<li>PEEK<\/li>\n\n\n\n<li>Ruostumaton ter\u00e4s<\/li>\n\n\n\n<li>Aluminum alloys<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">After curing, the silicone becomes permanently bonded to the substrate, forming a <strong>single integrated functional component<\/strong>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">3. Why LSR Is Ideal for Medical Devices<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">LSR offers unique advantages compared to traditional elastomers:<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3.1 High Biocompatibility<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Suitable for skin contact and internal medical use<\/li>\n\n\n\n<li>Complies with ISO 10993 and USP Class VI<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">3.2 Excellent Thermal Stability<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Resistant from -50\u00b0C to 200\u00b0C<\/li>\n\n\n\n<li>Compatible with autoclave sterilization<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">3.3 Chemical Resistance<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Stable against disinfectants and bodily fluids<\/li>\n\n\n\n<li>Low extractables and leachables<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">3.4 Precision Molding Capability<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Suitable for micro-scale medical components<\/li>\n\n\n\n<li>High repeatability in mass production<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">4. Key Engineering Design Considerations<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">4.1 Material Compatibility<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Not all plastics bond well with LSR. Engineers must consider:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Surface energy of substrate<\/li>\n\n\n\n<li>Use of primers or plasma treatment<\/li>\n\n\n\n<li>Thermal expansion mismatch<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">4.2 Bonding Mechanism<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">LSR bonding occurs via:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Chemical bonding (preferred)<\/li>\n\n\n\n<li>Mechanical interlocking (secondary structure)<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Strong bonding is critical for preventing delamination in medical environments.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4.3 Wall Thickness Control<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Uniform silicone thickness ensures:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Stable curing behavior<\/li>\n\n\n\n<li>Reduced shrinkage variation<\/li>\n\n\n\n<li>Consistent sealing performance<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Typical medical LSR wall thickness: <strong>0.3 mm \u2013 3.0 mm<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4.4 Mold Design Complexity<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">LSR overmolding molds require:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Precision alignment systems<\/li>\n\n\n\n<li>Venting for air evacuation<\/li>\n\n\n\n<li>Temperature-controlled cavities<\/li>\n\n\n\n<li>Multi-shot injection capability<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">5. Valmistusprosessin yleiskatsaus<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Step 1: Substrate Preparation<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Injection molded plastic or machined metal part<\/li>\n\n\n\n<li>Cleaning and surface treatment<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Step 2: LSR Injection<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Liquid silicone injected into mold cavity<\/li>\n\n\n\n<li>Controlled temperature and pressure<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Step 3: Curing Process<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Heat-activated crosslinking<\/li>\n\n\n\n<li>Rapid cycle time (typically 30\u201390 seconds)<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Step 4: Post-Curing (if required)<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Poistaa haihtuvia yhdisteit\u00e4<\/li>\n\n\n\n<li>Improves medical compliance<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Step 5: Inspection &amp; Testing<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Mitatarkkuus<\/li>\n\n\n\n<li>Bond strength testing<\/li>\n\n\n\n<li>Leak and pressure tests<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">6. Common Challenges in Medical LSR Overmolding<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">6.1 Delamination Issues<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Caused by:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Poor surface treatment<\/li>\n\n\n\n<li>Incompatible substrate materials<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">6.2 Flashing Defects<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Poor mold sealing<\/li>\n\n\n\n<li>Excess injection pressure<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">6.3 Inconsistent Bond Strength<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Variations in surface chemistry<\/li>\n\n\n\n<li>Contamination during molding<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">7. Applications in Medical Devices<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">LSR overmolding is widely used in:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Drug delivery systems<\/li>\n\n\n\n<li>Infusion pumps<\/li>\n\n\n\n<li>Respiratory masks and connectors<\/li>\n\n\n\n<li>Surgical instrument grips<\/li>\n\n\n\n<li>Catheter sealing systems<\/li>\n\n\n\n<li>Diagnostic device interfaces<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">8. Future Trends<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The medical LSR industry is evolving toward:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Micro-precision overmolding (&lt;100 \u03bcm structures)<\/li>\n\n\n\n<li>Multi-material integration (silicone + electronics)<\/li>\n\n\n\n<li>Smart medical device interfaces<\/li>\n\n\n\n<li>Fully automated cleanroom production lines<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">9. Johtop\u00e4\u00e4t\u00f6s<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">LSR overmolding is a critical enabling technology in modern medical device manufacturing. Engineers must carefully consider <strong>material compatibility, mold design, bonding mechanisms, and regulatory compliance<\/strong> to ensure high-performance and safe medical components.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">With increasing demand for minimally invasive and high-reliability devices, LSR overmolding will continue to play a central role in the future of healthcare engineering.<\/p>","protected":false},"excerpt":{"rendered":"<p>1. Introduction Liquid Silicone Rubber (LSR) overmolding has become one of the most important manufacturing technologies in modern medical device engineering. It enables the combination of rigid substrates (plastic or metal) with soft silicone sealing or functional layers, creating components that meet strict requirements for biocompatibility, sealing performance, and long-term durability. Applications include: For engineers, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":2341,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center 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