Liquid Silicone Rubber (LSR) Parts: Injection-Molded

Liquid silicone rubber (LSR) parts are produced by injecting two-part platinum-cure silicone into a heated mold—a fully automated, flash-free process ideal for high-volume, high-purity components. At Anlintech we mold LSR gaskets, seals, diaphragms, valves, and multi-component parts with tight tolerances and consistent lot-to-lot quality. Start with our what is LSR primer and the LSR molding process guide.

Why Choose LSR

• Automated, flash-free molding – no deflashing, lower unit cost at volume.
• High purity – platinum cure, no peroxide residues; FDA & USP Class VI grades.
• Stable properties – -60°C to +230°C, excellent flexibility and dielectric strength.
• Complex, thin-wall parts – fills micro-features injection compression cannot.
• Overmolding – bonds to thermoplastics and metals in one shot.

LSR vs Other Silicone Processes

See compression vs injection molding and our broader silicone rubber parts page for process selection.

Material Grades

• General-purpose LSR – 30–70 Shore A for seals and gaskets.
• Medical / USP Class VI – per ISO 10993 / FDA for invasive and food contact.
• Self-lubricating & conductive – for valves, diaphragms, and EMI gaskets.
• Optically clear & flame-retardant – lighting and electronics.

How to Specify LSR Parts

1. Part geometry and tolerance (we hold ISO 3302-1 Class 1/2).
2. Hardness, color, and translucency.
3. Regulatory grade (FDA, USP Class VI, NSF, UL 94).
4. Overmolding substrate, if any.
5. Annual volume (drives tooling and cycle strategy).

For material property detail, see our silicone rubber complete guide and medical-grade LSR article.

Typical Applications

• Medical & pharma – valves, diaphragms, seals (see medical silicone components).
• Food & beverage – gaskets and dispensing seals (see food & beverage seals).
• Automotive – connectors, grommets, and sensors.
• Electronics – waterproof seals and keypads (see IP67/IP68 sealing).

Frequently Asked Questions

What is the difference between LSR and regular silicone?

LSR is a two-part liquid cured by platinum; it is injected automatically and is flash-free. Traditional silicone (HCR) is a milled gum cured in compression molds—better for low volumes and very large parts.

Is LSR food- and medical-safe?

Yes. Platinum-cure LSR is available in FDA, USP Class VI, and NSF grades with full traceability for food, beverage, and medical contact.

Can LSR be overmolded onto plastic?

Yes. LSR bonds to many thermoplastics (e.g., PA, PBT) and metals in a single two-shot process with proper pretreatment.

When is LSR cheaper than compression molding?

At higher annual volumes, LSR’s automation and zero-deflash outweigh its higher tooling cost; for prototypes and small runs, compression molding is usually cheaper.

Get a Quote

Send your 3D file or sample with volume and grade. Request an LSR quote → or see our FAQ. Back to custom rubber parts.