HOME E SERVICES TECHNICAL ASSISTANCE PRODUCTS TECHNOLOGIES AUTOMATION ABOUT NEGRI BOSSI NEWS & EVENTS CAREERS CONTACT US Home > TECHNOLOGIES > Liquid Silicone Rubber (LSR) Liquid Silicone Rubber (LSR) LIQUID SILICONE RUBBER INJECTION MOULDING TECHNOLOGY For many years, Negri Bossi has maintained a strong involvement with the Liquid Silicone Rubber (LSR) injection moulding sector. In collaboration with the leading suppliers of material delivery systems and specialist mould makers, Negri Bossi has delivered turnkey systems for all types of LSR applications to many parts of the world. Some examples of LSR applications include: MEDICAL Teats for baby feeding bottles Orthopaedic insoles Cardiac valve membranes Medical probes Medical tube fittings AUTOMOTIVE Spark plug covers Braking system seals Cylinder head seals ELECTRICAL & APPLIANCE Clothes iron boiler seals Waterproof socket and plug covers Electrical insulating covers Grommets SPORTS Swimming masks Swimming goggles and lenses Snorkelling and diving mouthpieces Depth gauge covers GENERAL APPLICATIONS Gas masks Heat resistant mats Shower mats Ice makers Cake containers MULTI-MATERIAL / MULTI-COMPONENT Showerheads Rain sensors Swimming masks SEND ME INFORMATION LSR Machine LIQUID SILICONE RUBBER MOULDING MACHINE The Negri Bossi LSR solution features a standard injection moulding machine that is fitted with special LSR injection unit, LSR equipment options and LSR software. 1. The two component materials required for the LSR process are metered to the injection unit by a special delivery system. 2. The materials pass through a static mixing device… 3. … and into the machine barrel. 4. To prevent premature curing of the combined LSR materials, the barrel is fitted water jackets that allow closed loop thermal regulation. 5. The material is metered through an LSR tip assembly using a zero compression short L/D LSR screw, then during injection, through a pneumatically or hydraulically actuated, liquid-cooled, pin-type shut-off nozzle, and finally through a special LSR nozzle tip and into the mould. The machine is also equipped with a range of features that are required for the LSR process and can also be fitted with several optional devices that may be useful to the process in specific circumstances. Typical Features and Options: LSR Injection Unit (Special barrel and LSR screw with static seal) losed loop liquid barrel cooling Pin-type shut-off nozzle (Pneumatic or hydraulic actuation) LSR nozzle tip with static seal LSR tip assembly and non-return valve (Optional spring-lock positive shut-off design) Carriage decompression control Integral mold temperature control system Insulated platens LSR closed loop process software package for precise volumetric control Mould vacuum system (Vacuum pump, vacuum switch, interface, control software) Mould sweep software and sweep device interface Mould cold deck valve gate control system Air blow with pressure regulation Pre-dosing assembly with two component temperature controlled static mixer and purge valve LSR material delivery system LSR Injection Unit LIQUID SILICONE RUBBER INJECTION UNIT The LSR process requires an injection unit designed specifically for the material and process. This unit should be appropriately sized for the application. Typically, this means that the component shot weight should be within 1 to 5 screw diameter stroke range. The main features are: LSR nozzle tip with static seal Pin-type, liquid cooled, shut-off nozzle (Pneumatic or hydraulically actuated) Closed loop liquid temperature control LSR zero compression 15:1 L/D screw with shank seal LSR non-return valve (Available with spring-lock positive shut-off) LSR dosing adapter Seal LSR Dosing Unit LIQUID SILICONE RUBBER DOSING UNIT The Negri Bossi LSR solution features a standard injection moulding machine that is fitted with special LSR injection unit, LSR equipment options and LSR software. The two components, once mixed in the desired ratios, are metered to the injection unit by a special delivery system. Negri Bossi partners with several suppliers of this specialist equipment to provide a turn-key LSR solution. Or, if the customer already has existing LSR delivery equipment, this can be easily interfaced to work with a suitably-equipped Negri Bossi LSR machine. LSR Multi-Material Process LIQUID SILICONE RUBBER MULTI-MATERIAL PROCESS With a specially configured Negri Bossi MultiMat® LSR machine, and a specially-designed mould, it is possible to produce multi-material components that feature LSR as one of the elements. The LSR injection unit is usually on the main axis of the machine, but can also be arranged in a lateral or vertical position. The table below shows the compatibility of LSR with a range of thermoplastic materials when used in combination, in a multi-material application. Applicable Models APPLICABLE MODELS NOVA eT Markets Served Medical Caps & Closures Packaging Optical Moulding NOVA sT Markets Served General Small & Medium Size Parts Automotive Construction Industrial Appliance Household Aerospace Electronic & Telecomm Technical Moulding Packaging Food & Beverage Containers Closures PRODUCTS NOVA eT (50-450 tonnes) NOVA sT (180-500 tonnes) NOVA iT (550 – 1150 tonnes) NOVA sT (600 – 1300 tonnes) VECTOR (650 – 1300 tonnes) BIPOWER (1300-7000 tonnes) NEGRI BOSSI TECHNOLOGIES AUTOMATION ABOUT NEGRI BOSSI NEWS & EVENTS DOWNLOAD AREA E-SERVICES CONTACT & DISCLAIMERS CONTACT US TECHNICAL ASSISTANCE SITEMAP LEGAL CAREERS SUBSCRIBE TO OUR NEWSLETTER SYTRAMA Click here to learn more about Sytrama part removal robots. Copyright Negri Bossi S.P.A.