Two-Component LSR Overmolding Machine Silicone Bonding Plastic Insert Molding Equipment for Sealing Components

Two-Component LSR Overmolding Machine for Silicone Bonded Plastic and Metal Inserts

Many silicone products cannot be moulded as a single material. Grips, seals, keypads and wearable bands need a rigid plastic or metal core with a soft silicone skin bonded to it, and the bond must survive pull tests, heat ageing and repeated flexing. This two-component LSR overmolding machine is built for exactly that job: inserts are located in the mould, self-adhesive or primed LSR is injected directly onto the insert, and the part leaves the mould as one finished assembly.

We design the machine configuration together with the mould and the bonding strategy, because overmolding quality depends on the combination of insert preparation, mould temperature, injection position and cure profile rather than on the machine alone.

Technology Highlights

• Overmolding-ready clamping unit: mould platens and tie-bar spacing accept insert fixtures and slide cores, with options for two-station or shuttle operation so inserts are loaded while the other station moulds.
• Self-adhesive LSR support: the metering unit handles self-bonding silicone grades, and the machine controls mould temperature closely so adhesion develops without primer in most plastic pairings.
• Insert location and retention: vacuum cups, mechanical pins or magnetic fixtures hold inserts in position against injection pressure, preventing displacement and flash.
• Cold runner with needle valve: direct gating onto the insert reduces material waste and keeps gate marks away from visible surfaces.
• Multi-stage injection: controlled fill speed and packing pressure avoid washing the insert out of position and reduce stress at the bond interface.
• Two-component process control: separate recipes for insert type, mould and silicone grade, with parameter interlocks so a wrong combination cannot be run.
• Automation interface: signals for insert feeding, robot take-out and vision inspection allow the machine to be integrated into a semi or fully automatic cell.

Typical Applications

• Automotive: connector seals over moulded onto plastic housings, grommets, sensor boots and damping elements with metal inserts.
• Wearables and consumer electronics: watch bands and wrist straps moulded onto plastic clasps, waterproof buttons, keypads and grips.
• Kitchenware and household: pot and lid handles, utensil grips and tool handles over metal or rigid plastic cores.
• Medical devices: soft grips on rigid instrument bodies, seals on connector housings and soft-touch patient contact parts.
• Industrial hardware: sealed cable entries, gaskets on metal flanges and protective covers.

Advantages for Southeast Asian Manufacturers

• Fewer process steps: bonding replaces separate moulding plus manual assembly and adhesive work, cutting labour cost and rework.
• Consistent bond strength: controlled mould temperature and injection profile give repeatable peel and pull results, which is essential for automotive and medical customers.
• Better surface quality: cold runner gating and controlled packing reduce flow marks and flash on visible silicone surfaces.
• Designed for tropical plants: cooling and cabinet ventilation are specified for high ambient temperature and humidity across Southeast Asia.
• Local engineering support: English-speaking service engineers, remote diagnostics, spare parts from Guangdong and on-site training for operators and mould setters.

Configuration and Options

Standard scope includes the LSR injection and clamping unit, metering package, overmolding mould platen arrangement, cold runner set, water chiller, insert fixture interface, tool kit and manual. Options include shuttle or rotary table, vacuum insert holding, pigment metering, robot interface, vision inspection signal, mould temperature controllers and guarding to plant standard. Joint mould and bonding development is available.

Frequently Asked Questions

Do I need primer? It depends on the plastic and silicone grade. Self-adhesive LSR covers many engineering plastics; for difficult pairings we recommend plasma treatment or primer and will confirm during sampling.

Can you supply the mould too? Yes, mould and insert fixture development is available through our partner tool shop, or we can adapt your existing mould.

How do we validate the bond? We run sampling parts and support peel and pull testing with your quality team before shipment.

Contact Us

Send the insert drawing, plastic material and bond requirement, and our engineers will propose the overmolding configuration and sampling plan.