Uniform freezing of melt in the mould dependent on

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Unformatted text preview: ances will result in moulded-in stress. This is the biggest culprit for over 50% part failure Applications of Injection moulded parts • • • • • • • • • • • • • • • Power-tool housing Telephone handsets Television Cabinets Electrical Switches DVDs Automotive bumpers Automotive dash boards Battery Casings Syringes Drug Inhalation Units Disposable razors Washing-up bowls Wheelie binsCrates/ Recycling boxes Bottle Lids/closures Types Types of Injection Moulding Multi-shot (or 2K moulding) (where different materials are injected into the same mould), Insert moulding (where metal components are incorporated). Structural foam moulding (where the material is foamed to reduce density) Gas assisted moulding (where gas is in corporated to reduce wall thickness). Insert Moulding • Insert moulding • ABS, PA, PC, GPPS,PP Structural Structural Foam Moulding Structural Foam is a term commonly used to describe thermoplastic injection moulding components made by the injection moulding process which have a cellular core. Gas Gas Assisted Moulding The main two types of Gas Assisted Moulding are Either inject the gas into the component cavity (internal gas injection), Or to use the gas on the outside surface, but still within the mould cavity, to consolidate the component (external gas injection). Internal Gas Injection - Most widely used process External Gas Injection - used for enhanced surface definition Gas Gas Assisted Moulding Automotive Bumper Dash Panel External External Gas Assisted Moulding Applications: Flat panels for office equipment. Computer enclosures. Furniture, i.e. tabletops. Automotive panels. Domestic appliances EXTRUSION EXTRUSION The extrusion process Introduction Introduction Extrusion: (Greek) push out Pump supplies a continuous stream of material to a shaping tool or to some other subsequent shaping process. Materials plastics metals (Al window frames spaghetti and other noodles toothpaste Extrusion useful for shaping parts with extruder dies Extrusion is basis for injection molding and blow molding The The extrusion process Plastic granulate is supplied via the feed hopper to the extruder Homogenous melted material from thermoplastic granulate under high pressure in an extruder (screw press) or co-extruder Shaping of the molten mass to a continuous web by means of flat sheet dies Calibration of the emerging material to the desired thickness using a 3-roller flattening calender Tension-free cooling of the web to ambient temp...
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