液态硅胶 (LSR) 和橡胶制品

LSR and Rubber Molding Engineered for Functional Performance

Liquid silicone rubber and elastomer parts are defined by more than shape. Sealing force, flexibility, compression set, tear strength, temperature, chemical exposure, surface feel, color, bonding and regulatory requirements can all affect the material and molding process. Rilong supports LSR injection molding and silicone or rubber compression molding from part review and tooling through trials, inspection, secondary operations and delivery.

The process route is selected around the specified compound, geometry, annual volume, cosmetic standard, flash limit, validation plan and total program economics. LSR injection molding can support automated, repeatable production of intricate parts, while compression molding remains practical for many solid silicone and rubber compounds, part formats and project volumes.

Design for LSR and Rubber Molding

Elastomers stretch and deform, but that flexibility does not remove the need for disciplined DFM. The design review considers how uncured material fills the cavity, where air escapes, how the part separates from the tool, and how the molded geometry behaves after cooling and conditioning.

Choosing the Appropriate Elastomer Molding Process

Selecting Silicone, Rubber or Thermoplastic Elastomer

The material family should be selected from the actual operating environment. Hardness alone does not predict sealing, durability or processing. Temperature range, fluid exposure, weathering, compression set, tear, abrasion, rebound, electrical properties, color, odor, sterilization, bonding and applicable compliance requirements should be reviewed together.

LSR Overmolding and Insert Bonding

Bonding LSR or rubber to another material requires a compatible system, not only contact between two surfaces. The review covers substrate grade, thermal resistance, surface cleanliness, primer or adhesive, plasma or other preparation where specified, molding temperature, insert movement and the geometry available for mechanical retention.

Shutoffs around the insert must control flash without damaging the substrate. Holes, grooves, ribs and undercuts can create a mechanical lock when chemical adhesion is unavailable or needs reinforcement. Bond strength and leak performance should be validated using a test method that represents the part’s intended load.

Process Control, Post-Cure and Quality Validation

A stable elastomer process controls material identity, mix or batch condition, mold temperature, fill behavior, cure, demolding and secondary handling. Where required by the selected compound or application, post-curing can be specified to develop properties or reduce residual volatiles. Post-cure conditions must be agreed because they can also affect dimensions, color and production lead time.

• Incoming material: verify the specified compound, color, batch and required documentation.
• Tool trial: evaluate filling, venting, flash, cure, demolding, surface condition and process stability.
• Dimensional validation: measure critical characteristics after the agreed cooling, conditioning or post-cure state.
• Functional checks: define application-relevant tests such as hardness, seal, leak, compression, bond or visual acceptance where required.
• Final inspection: inspect agreed dimensions and workmanship, then package parts to prevent distortion, contamination or cosmetic damage.

What to Send for an Accurate LSR or Rubber Molding Quote

• 3D CAD model and a 2D drawing showing critical dimensions, tolerances and datums.
• Specified compound or operating requirements such as temperature, chemicals, hardness, color and compliance.
• Annual volume, order quantity, target tool life and delivery schedule.
• Flash limit, parting-line restrictions, gate restrictions, surface texture and cosmetic zones.
• Insert material and drawing, bonding requirement, pull or peel test, leak test and any surface preparation.
• Post-cure, cleanliness, inspection reports, certification, packaging and delivery requirements.

Related capabilities include mold design and tooling, overmolding and insert molding, two-shot molding, and plastic injection molding.

LSR and Rubber Molding FAQ

What is the difference between LSR injection molding and silicone compression molding?

LSR injection molding meters and mixes two liquid components and injects them into a heated mold, supporting automated production and complex repeatable parts. Compression molding places a measured charge of solid silicone or rubber into a heated cavity and can be practical for different materials, geometries, quantities and tooling strategies.

How is flash controlled on liquid silicone rubber parts?

Flash control depends on precise parting surfaces and shutoffs, adequate tool stiffness and clamping, controlled vent depth, balanced filling, material behavior and stable process pressure. Flash limits and cosmetic zones should be defined before mold design.

Which elastomer should be used for a molded rubber part?

Selection depends on temperature, chemicals, weathering, compression set, tear and abrasion, hardness, color, electrical behavior, bonding, sterilization or regulatory requirements and cost. Silicone, EPDM, NBR, CR, FKM, TPU and TPE have different performance profiles.

Can LSR or rubber be overmolded onto plastic or metal?

Yes, when the substrate, elastomer, surface preparation, insert design, mold sealing, temperature exposure and bonding method are compatible. Some combinations use chemical adhesion or primer, while others rely on mechanical retention.

What information is needed for an LSR or rubber molding quote?

Provide 3D and 2D files, material or performance requirements, hardness, color, annual and order quantities, critical dimensions, flash and cosmetic limits, post-cure or cleanliness requirements, insert details, validation documents, packaging and delivery destination.