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Liquid Silicone
An addition cured Silicone which is processed in modified plastic injection moulding presses. Liquid Silicone is similar in properties to normal Silicone but varies in its processing characteristics. It is purchased as a two part raw material with a viscosity similar to Vaseline. The two materials are pumped from a drum through a mixing head and injected into the cavities. Very low pressures are involved and very fast cures (typically 20-45 seconds).
Properties
• Similar to those of normal Silicone rubber, plus:
• full range of hardnesses can be achieved
• extremely clean process enabling colour matching
• fast cycles and low material usage offers significant
cost advantages on long runs
Limitations
• lower strength, particularly where harder grades are
used
• tooling is very expensive (up to 10x normal rubber
tool cost) due to low viscosity and the need to
remove air and prevent flash
• short runs are not viable due to the difficulties of
setting up. Liquid silicone should only be
considered for long runs, particularly where the
weight to part size ratio is low.
Typical Applications
• baby bottle teats
• thin diaphragms
• syringe plungers
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