Flashcards
molding processs
Cards in this deck (9)
- 1injection Moulding Typical Materials Used: Acrylonitrile-Butadiene-Styrene (ABS), Nylon (PA), Polycarbonate (PC), Polypropylene (PP) and Polystyrene (GPPS) Typical Products Produced: 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 bins, Crates/Recycling boxes and Bottle Lids/closuresinjection Moulding (or Molding to use the US spelling), along with extrusion ranks as one of the prime processes for producing plastics articles. It is a fast process and is used to produce large numbers of identical items from high precision engineering components to disposable consumer goods.
- 2Rotational moulding Rotational moulding differs from other processing methods in that the heating, melting, shaping, and cooling stages all occur after the polymer is placed in the mould, therefore no external pressure is applied during forming. This provides the following advantages Economically produced large products, Minimum design constraints, Stress-free products, No polymer weld lines and Comparatively low mould costs.Rotational moulding (often referred to as Rotamoulding or Rotomoulding) is a process used for producing hollow plastic products. By using additional post-moulding operations, complex components can be produced enabling the process to compete effectively with other moulding and extrusion practices.
- 3Thermoforming is one of the oldest and most common methods of processing plastic materials. Vacuum formed products are all around us and play a major part in our daily lives.The process involves heating a plastic sheet until soft and then draping it over a mould. A vacuum is applied sucking the sheet into the mould. The sheet is then ejected from the mould. In its advanced form, the vacuum forming process utilizes sophisticated pneumatic, hydraulic and heat controls thus enabling higher production speeds and more detailed vacuum formed applications.
- 4To the right is an example of a vacuum formed toy. The simple 'lorry' mould has been placed in a vacuum former and a compressed polystyrene sheet has been placed above it. The polystyrene has been heated and then vacuum formed to the shape of the mould.Vacuum forming is a technique that is used to shape a variety of plastics. In school it is used to form/shape thin plastic, usually plastics such as; polythene and perspex. Vacuum forming is used when an unusual shape like a ‘dish’ or a box-like shape is needed. Below you can see the stages involved in vacuum forming.
- 5Typical Materials Used: Polypropylene (PP), Polyethylene (PE), Polyethylene - Terephthalate (PET) and Polyvinyl chloride (PVC) Typical Products Produced: Bottles and containers, Automotive fuel tanks, Venting ducts, Watering cans and Boat fenders etcThe blow moulding machine is based on a standard extruder barrel and screw assembly to plasticise the polymer. The molten polymer is led through a right angle and through a die to emerge as a hollow (usually circular) pipe section called a parison.
- 6Typical Materials Used: Polyethylene (Low Density) LDPE, (LLDPE), Polypropylene (PP), Polyethylene - Terephthalate (PET), Polyvinyl chloride (PVC), Polyethylene (High Density) HDPE) Typical Products Produced: Plastic BottlesInjection blow moulding is used for the Production of hollow objects in large quantities. The main applications are bottles, jars and other containers. The Injection blow moulding process produces bottles of superior visual and dimensional quality compared to extrusion blow moulding. The process is ideal for both narrow and wide-mouthed containers and produces them fully finished with no flash.
- 7Materials such as polystyrene, nylon, polypropylene and polythene can be used in a process called extrusion. These are thermoplastics - this means when they are heated and then pressured in a mould they can be formed into different shapes and sectionsA machine used to extrude materials is very similar to the injection moulding machine. A motor turns a thread which feeds granules of plastic through a heater. The granules melt into a liquid which is forced through a die, forming a long 'tube like' shape. The extrusion is then cooled and forms a solid shape. The shape of the die determines the shape of the tube.
- 81. The mould is heated. 2. A 'slug' or piece of the selected plastic is placed into the mould and warms up. 3. The hydraulic press begins to move down when the plastic has reached the correct temperature.. 4. As the upper and lower mould meet, the plastic is compressed into the shape of the mould. 5. The upper mould moves upwards and the plastic piece (in this case a tray) is removed.Moulding through the force of compression is another very common industrial process. The materials used are melamine formaldehyde, phenol and urea. These materials can be formed into different shapes through applying both heat and pressure, other plastics do no have these properties.
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- 8 kartik Flashcards on molding processs, created by Kartik Kamli on 22/11/2015.
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- Kartik Kamli
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