Design

• Plastic Processes


  Injection Moulding, Extrusion & Blow Moulding
• Injection Moulding


  1. Granules of plastic powder poured/fed into hopper

  2. Heater heats tube, screw thread turns

  3. Motor turns thread, melts granules into liquid

  4. Liquid forced into mould, cools into shape

  5. Mould opens, unit removed
• Extrusion


  Same operations as injection moulder, but plastic forced out through hole into long shape with continuous fixed cross section
• Blow Moulding


  HDPE removed from mould, excess trimmed away
• Rotational Moulding


  1. Mould filled with plastic powder

  2. Mould heated to 300°C, rotates to force powder against wall

  3. Mould cooled, allowing plastic to solidify

  4. Finished product removed
• Rotational Moulding


  Four stage process used for creation of hollow plastic projects
• Vacuum Forming


  1. Sheet of plastic heated, air below sucked away to form around mould

  2. Commonly used with thin plastics
• Compression Moulding


  Plastic simply squeezed into desired shape, commonly uses thermosetting plastics
• Metalwork Processes


  Die Casting, Cold Rolling/Extrusion & Piercing & Blanking
• Die Casting


  1. Molten metal taken from furnace, pumped into casting

  2. Allowed to cool

  3. Clamping unit lowers pressure, mould opens, unit removed
• Die Casting


  Similar to Injection Moulding, except with molten metal
• Piercing & Blanking


  Simple process cutting shapes out of sheet metal, can produce many intricate styles concisely and repeatedly
• Piercing, Blanking & Forming


  Forming process is hydraulic press, forming blank into desired shape
• Extrusion & Cold Rolling

  Metal extrusion process more or less same as plastic, but technically not correct method for making metal tubes. Cold rolling is correct method, metal rolled into tubular shape via rolling press.
• Drop Forging

  Piece of yellow hot metal placed into bottom die, rammed by top die to form into shape
• Drop Forging

  Similar process in some ways to Compression Moulding for plastics, can be done with steel, aluminium, some brasses and bronzes
• CAM - Computer Aided Manufacture

  JIT, CIM, CNC, 3D Printing & Standard Components
• Just In Time Production

  1. Companies order in things they need for a product, arriving ready for dispatch

  2. When order arrives, processed quickly, materials/components ordered from supplier, arrive within 24 hours

  3. As soon as materials/components arrive, processed on production line

  4. When batch ready, distribution to customer, often subcontracted to haulage company
• Just In Time Production

  The name given to the process of companies ordering in things they need for a product they are making and arriving ready for dispatch
• Standard Components


  Individual parts manufactured in thousands/millions to same specification, can lower cost of manufacture and offer quality assurance, delivered at point of dispatch so no need for storage/manufacture
• CNC - Computer Numerical Control Production

  Computer converts CAD design into numbers for production, examples include CNC Router, CNC Miller, CNC Lathe, 3D Printer
• CIM - Computer Integrated Manufacture

  Automation of manufacturing facility using computer aided technologies
• 3D Printing

  Production of object created in CAD software, form of rapid prototyping, can quickly produce physical model for testing
• Injection Moulding

  Generally identified by: Injection Mark/Nipple, Sprue Marks, One piece of plastic, Split lines, Flash
• Common Materials for Injection Moulding

  • Epoxy
  • Nylon
  • Polyethylene (PE)
  • Polystyrene (PS)
• Extrusion

  Generally identified by: Uniform Cross Shape, Faint line down one side
• Common Materials for Extrusion

  • Polyethylene (PE)
  • Polypropylene (PP)
  • Polyvinyl Chloride (PVC)
  • Acrylonitrile Butadiene Styrene (ABS)
• Blow Moulding


  Generally identified by: Injection Mark/Nipple, Hollow with one open end, Split lines, Flash
• Common Materials for Blow Moulding

  • Polyethylene Terephthalate (PETE)
  • Polypropylene (PP)
  • Polyvinyl Chloride (PVC)
• Rotational Moulding


  Generally identified by: Always hollow but sealed, Small vent hole, Thin outer layer
• Common Materials for Rotational Moulding

  • Polyethylene (PE)
  • Polypropylene (PP)
  • Polyvinyl Chloride (PVC)
• Vacuum Forming

  Generally identified by: Vent hole, Slightly rounded edges, Tapered edges, Thin outer layer
• Common Materials for Vacuum Forming

  • High Impact Polystyrene (HIPS)
  • High Density Polythene (HDPE)
  • Acrylonitrile Butadiene Styrene (ABS)
• Compression Moulding

  Generally identified by: Slight inconsistencies, Intricate detail, Split lines, Sprue marks
• Common Materials for Compression Moulding

  • Urea Formaldehyde (UF)
  • Polycarbonate (PC)
  • Polyvinyl Chloride (PVC)
• Die Casting


  Generally identified by: Intricate shapes, Consistent across each item
• Die Casting can be done with the majority of metals
• Piercing, Blanking & Forming


  Generally identified by: Created from one piece of sheet metal
• Piercing, Blanking & Forming can be done with the majority of metals in sheet form
• Extrusion & Cold Rolling


  Generally identified by: Uniform cross section, May have a slightly visible seam