Name: Liquid Silicone Rubber (LSR) Overmolding
Brand: PANDA
SKU: liquid-silicone-rubber-overmolding
Availability: InStock

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Liquid Silicone Rubber (LSR) Overmolding from Panda Molding eliminates flash, adhesion failures, and cycle‑time overruns that plague medical device production. Our ISO9001‑certified process combines cold‑runner injection, inline AOI inspection, and biocompatible material traceability to deliver precision components—from respiratory masks to surgical tools—with reliable high‑volume output and zero recall risk.

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Liquid Silicone Rubber (LSR) Overmolding — Custom Injection Molding by Panda Molding

Liquid Silicone Rubber (LSR) Overmolding is a high‑precision injection molding service that bonds medical‑grade silicone directly onto thermoplastics, metals, or other substrates in a single automated cycle. It is the go‑to solution for engineers who need hermetic seals, soft‑touch grips, or flexible diaphragms on rigid components—without adhesives or secondary assembly. Panda Molding’s approach integrates self‑adhesive LSR grades, cold‑runner tooling, and inline quality gates to eliminate the flash, delamination, and batch‑rejection risks that still plague conventional overmolding. With mold tolerances down to ±0.025 mm/mm and ISO 8 cleanroom production, we deliver parts that meet USP Class VI, ISO 10993, and FDA requirements for life‑science applications. (Packson Mold precision data)

Service Capabilities

Precision Tolerances: Achieve ±0.025 mm/mm dimensional accuracy using hardened steel LSR molds with cold‑runner systems that minimize gate vestige and flash. (Packson Mold)
Self‑Adhesive LSR Grades: Eliminate primers and plasma treatment for many plastic‑silicone bonds. Our material library includes grades that chemically bond to PC, PBT, PA, and stainless steel during cure, reducing cycle time and failure points. (Cirtec Medical adhesion challenges)
ISO 8 Cleanroom Molding: All medical LSR overmolding runs are performed in an ISO 8 cleanroom with HEPA filtration, positive pressure, and full gowning protocols to prevent particulate contamination. (ProSilicones64 cleanroom standards)
Inline Automated Inspection: AOI cameras check part geometry and surface finish, while checkweighers verify shot weight on every cycle. Out‑of‑spec parts are automatically rejected, and real‑time SPC data prevents drift. (TedeSolutions hygienic production)
Multi‑Cavity High‑Volume Production: Cold‑runner blocks with up to 64 cavities deliver consistent shot‑to‑shot uniformity, reducing per‑part cost and enabling annual volumes in the millions. Injection pressures are optimized between 250 and 10,000 psi to balance fill speed and flash control. (Cirtec process overview)

Industries & Applications

Medical & Surgical Devices: LSR overmolding creates soft, biocompatible grips on laparoscopic handles, sealing gaskets on insulin pumps, and vibration‑damping overmolds on wearable monitors. The process is validated to ISO 10993‑5, ‑10, and USP Class VI, ensuring no cytotoxicity or irritation—critical for skin‑contact and implantable components. (Simtec medical LSR properties)

Baby Care & Consumer Goods: Pacifiers, bottle nipples, and teething rings demand flawless surface finish and zero contamination. Our inline AOI and checkweighing systems, as highlighted by industry reports, catch shape deviations and weight shifts before they leave the cleanroom, eliminating the recall risk that can devastate a brand. (TedeSolutions recall risk analysis)

Respiratory & Drug Delivery: Overmolded silicone valves and seals in inhalers and nebulizers must maintain elasticity after millions of cycles. LSR’s compression set resistance and precise gate placement ensure consistent airflow and dose accuracy. Our cold‑runner system prevents premature curing in the runner, reducing material waste by up to 40%.

Diagnostic & Labware: Microfluidic chips and reagent reservoirs benefit from LSR’s optical clarity and low leachables. Overmolding directly onto cyclic olefin copolymer (COC) or glass creates leak‑free interfaces without adhesives that could interfere with assays.

Our Injection Molding Process

Material Metering & Mixing: Two‑part LSR is pumped from sealed drums through a static mixer at a precisely controlled 1:1 ratio. The blend enters a cooled barrel to prevent scorching, then is injected into a cold‑runner mold maintained at 20–30°C. (Cirtec process)
Cold‑Runner Injection & Cavity Fill: The cold runner keeps the LSR liquid until it reaches the gate, where the mold temperature (160–220°C) triggers rapid cure. Injection speed and pressure profiles are tuned per cavity geometry to avoid jetting, air traps, and knit lines. (Fictiv LSR molding complexity)
Overmolding & Cure: The substrate (plastic or metal insert) is robotically placed or molded in‑situ. Self‑adhesive LSR chemically bonds during the 30–90 second cure cycle; for non‑compatible substrates, inline plasma treatment activates the surface seconds before injection. (Adhesion solutions)
Demolding & Post‑Cure: Parts are ejected with minimal flash thanks to optimized parting lines and vacuum‑assisted venting. A secondary post‑cure oven (200°C for 2–4 hours) removes volatile siloxanes and stabilizes physical properties for medical use. (ProSilicones64 validation protocols)

Quality Assurance

Panda Molding’s ISO9001‑certified quality system governs every batch. First‑article inspection reports (FAIR) include CMM dimensional data, optical comparator profiles, and surface roughness (Ra) measurements per ISO 4287. In‑process, AOI cameras and checkweighers perform 100% inspection on critical features; any deviation beyond ±0.5% of target weight or ±0.05 mm on a seal lip automatically triggers a reject and root‑cause alert. (Inline inspection data) Material traceability is maintained from silicone lot number to finished part, and every shipment includes a Certificate of Conformance and, when required, biocompatibility test reports to ISO 10993. Our molds are validated with IQ/OQ/PQ protocols, and process capability studies (Cpk ≥ 1.33) are standard for medical programs. (Validation protocols)

Frequently Asked Questions

Q: What materials are compatible with Liquid Silicone Rubber (LSR) Overmolding?: A: Self‑adhesive LSR grades bond directly to many thermoplastics (PC, PBT, PA, PEI) and metals (stainless steel, titanium) without primers. For challenging substrates like PEEK or PP, inline plasma or corona treatment ensures a robust bond. We always conduct a material compatibility study and lap‑shear testing before production. (Cirtec adhesion data)
Q: What is the typical lead time?: A: Prototype single‑cavity molds can be delivered in 2–4 weeks, with first‑article samples shipped within 5–7 business days after mold qualification. Production multi‑cavity tools typically require 4–6 weeks, and bridge tooling options are available to accelerate pilot runs. (ProMed’s rapid transition approach)
Q: What are the MOQ requirements?: A: For prototyping and clinical builds, we accept orders as low as 100 parts using soft or prototype tooling. High‑volume production molds are optimized for runs of 50,000 to millions of parts annually, with per‑part cost decreasing significantly above 100,000 pieces. We help customers navigate the tooling investment so that even small initial quantities remain financially practical. (Seaway Plastics on volume challenges)

References & Further Reading

Request a Free Quote

Ready to eliminate overmolding failures and scale your medical device? Upload your CAD files or 2D drawings for a free, confidential DFM review. Our engineers will assess part geometry, material pairings, and tooling strategy, then return a detailed quote with lead‑time and cost‑down options within 48 hours. Competitive pricing, no‑obligation consultation—start your Liquid Silicone Rubber (LSR) Overmolding project today.

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Liquid Silicone Rubber (LSR) Overmolding

Overview