LSR / Silicone Molding

Liquid Silicone Rubber (LSR) and solid silicone compounds require specialized machine configuration - a dedicated feeding system, precise temperature control, and appropriate barrel and screw design for processing silicone materials that cure in a heated mold.

DA Series vertical machines can be reviewed for selected silicone projects, often with slide table handling. LSR suitability depends on material grade, part design, feed system, mold structure, and machine configuration.

Application Overview

What is LSR / silicone molding and what does it require?

The process

Liquid Silicone Rubber is a two-component system - Part A and Part B are mixed and fed into a specialized barrel. The material is injected into a heated mold where it cures (crosslinks) rapidly. Unlike thermoplastics, silicone cures irreversibly - the part cannot be re-melted once formed.

LSR processing requires a dedicated pumping and mixing system, a barrel and screw designed for low-viscosity silicone, precise temperature control, and a mold designed for silicone's high thermal expansion. These are specialized requirements beyond standard thermoplastic injection molding.

Key considerations for silicone molding

Silicone molding is fundamentally different from thermoplastic processing. Before selecting a machine, these factors require evaluation:

Feed system - LSR requires a metered pumping and mixing unit, not a standard hopper
Barrel and screw - designed for low-viscosity, thermally sensitive silicone
Mold temperature control - silicone cure conditions depend on the material grade and mold design, requiring stable mold heating
Part removal - cured silicone is flexible and may require special ejection or manual handling

Common Challenges

Production challenges in silicone molding

LSR processing presents unique challenges in material handling, cure control, and part handling compared to standard thermoplastic molding.

Material mixing and feed consistency

LSR is a two-part system - improper mixing ratio causes incomplete cure or material waste. A dedicated metering and mixing system is essential. The engineering team can discuss the appropriate feed system configuration after reviewing your LSR material specifications.

Mold design for silicone processing

Silicone has high thermal expansion - mold design must account for this. Cold-runner systems, venting for air escape, and proper gate design are critical for part quality. Mold temperature must be uniform across the cavity for consistent cure.

Part handling for flexible components

Cured silicone parts are flexible and can be difficult to eject automatically. Slide tables help operators access the mold for manual part removal. The table configuration should match the part geometry and handling method.

Configuration Review

Recommended machine configuration for silicone molding

Starting points - LSR suitability requires technical review. Not all vertical machines are configured for silicone processing. Final selection depends on material grade, part design, mold structure, and production conditions.

Machine series

DA Series

Standard vertical clamping + vertical injection. Selected configurations may be suitable for LSR processing after technical review. 15T-800T.

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Table configuration

Slide table

Lower mold slides out for accessible part handling. Commonly preferred for flexible silicone parts that need careful manual removal.

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Machine size must be confirmed from project data - Review projected mold area, cavity count, silicone material behavior, feed system, and part handling method.

Materials

Silicone materials for injection molding

Silicone material selection depends on end-use requirements such as temperature resistance, flexibility, sealing behavior, purity requirements, and market compliance documentation. Each grade has specific processing parameters.

LSR (Liquid Silicone Rubber)

Two-part pumpable silicone system. Fast curing, good for automated production. Common for baby care, medical, and consumer products. Requires dedicated feeding and mixing system.

High-Consistency Rubber (HCR)

Solid silicone rubber with higher viscosity than LSR. Different feeding mechanism required. Common for industrial seals, gaskets, and high-durometer applications.

Healthcare Application Silicone

Silicone grades used for healthcare-related components may require tighter material specifications. Product suitability and regulatory documentation must be confirmed per product and market.

Kitchen and Baby Care Silicone

Silicone grades for kitchen, container, or baby feeding products require material certification for the intended market. Processing should be reviewed from the supplier material data and product requirements.

Fluorosilicone

Silicone with improved chemical and fuel resistance. Common for aerospace and automotive seals exposed to fuels and oils. Higher cost, specialized processing.

Electrically Conductive Silicone

Silicone filled with conductive particles for EMI shielding gaskets and electrical contacts. Specialized material with unique processing requirements. Requires mold material and parameter review.

Products

Typical silicone molded products

Silicone is selected when flexibility, temperature resistance, sealing behavior, or chemical stability is required beyond standard thermoplastic behavior.

Seals & gaskets

O-rings, flange gaskets, diaphragm seals - high-temperature and chemical-resistant sealing components.

Baby care products

Baby bottle nipples, pacifiers, and teething products require documented silicone grade, mold design review, and market-specific compliance confirmation.

Healthcare-related components

Catheter components, respiratory masks, and seals require project-specific review of material documentation, mold design, and production control requirements.

Flexible consumer goods

Kitchen utensils, bakeware, protective covers - heat-resistant silicone for consumer applications.

DA Series - Standard Vertical Injection Vertical clamping + vertical injection. Selected configurations may be suitable for LSR processing. Slide Table Machines Accessible part handling for flexible silicone parts. Overmolding Related process - silicone overmolding onto substrates. Medical Components Silicone is common in medical device component molding.

FAQ

LSR / Silicone molding - frequently asked questions

Can vertical machines process LSR (Liquid Silicone Rubber)?

Selected DA Series vertical machines can be configured for LSR processing. LSR requires a dedicated feeding system and specialized barrel and screw design - this is not a standard configuration for all machines. The engineering team can discuss LSR suitability after reviewing your specific material grade, part design, and production requirements.

Why use a vertical machine for silicone molding?

Vertical clamping can be advantageous for silicone parts that require insert loading or careful mold access. The vertical orientation helps with part ejection for certain geometries. However, LSR suitability depends on the specific machine configuration - not all vertical machines are set up for LSR processing.

How should machine size be reviewed for silicone molding?

Tonnage should be reviewed from the projected area, cavity count, silicone grade, mold structure, and removal method. Silicone processing also depends on the feed system and mold temperature control, so machine size should be discussed after the project data is clear.

Which table configuration is recommended?

Slide tables provide accessible part handling for silicone parts, which can be flexible and require careful removal. Fixed platen may suit simpler geometries. The choice depends on part design, ejection method, and whether inserts are used.

What silicone materials can be reviewed?

LSR (Liquid Silicone Rubber) and solid silicone compounds - depending on machine configuration, feed system, and processing parameters. Each material grade has specific curing temperature and injection requirements. The engineering team can discuss suitability after reviewing your material specifications.

What are common applications for silicone molding?

Silicone is often selected for flexibility, temperature resistance, and stable sealing behavior. Common applications include seals, gaskets, healthcare-related components, baby care products, and kitchen or container parts. The final material grade and compliance documentation must be confirmed for the target product and market.

How do I discuss machine configuration for silicone molding?

Send your product details, silicone material specifications, mold dimensions, and production volume through the contact form. An applications engineer can review the project data and discuss whether a vertical machine configuration is suitable for your silicone molding application.

Tell us about your silicone molding application

Discuss machine configuration for your silicone molding project

Send your product details, silicone material specifications, mold dimensions, and production target. The engineering team can review the project data and discuss suitable machine configurations for your silicone application.

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