Process Injection moulding
For parts of all sizes which require accurate and complex geometry.
Granular plastic or pellets are melted by friction with a rotating screw and actual heating, and then injected into the mould.

Normally, the process is reserved to thermoplastics, but it can be used for shaping fibre reinforced thermoplastics or thermosettings.

When shaping composites, parts with good mechanical properties cannot be produced as the content of fibres must be limited.
Production volumes are medium to large, and the cycle time per part is very short.
Danish Name Sprøjtestøbning
Category Mass conserving processes, Shaping plastics
Materials Plastics
Composites
Typical products Disposable drinking glass
Hedge cutter
Milestone
Razor, biodegradable
Razor, ordinary
Shaver, rechargeable
Spoon, clasp type
Satellite box
Washing machine drum
Gear
Hinge for gramophone lid
Video front-panel
Competing processes Extrusion
Gas assisted injection moulding
References A. Johnsen Industri A/S
Helarco
Jotun Danmark A/S
Molytex A/S
Price notes The mould is normally very expensive since it is often made from hardened steel in order to withstand high pressures. The mould cavities are often made with Electric Discharce Machining (EDM).
Additional info Possible to achieve good dimensional accuracy and surface finish.
Photo Thomas Nissen (Computer graphics)
Copyright © 1996-2004 Torben Lenau
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