Metal and plastic processes + plastic properties

Metal and plastic processes + plastic properties

1. Processes

   • Metal
     • Sand Casting
     • Forging
     • Welding
       • Spot welding
       • MIG (metal inert gas)
         • Similar to arc welding but has a inert gas used to provide a protective cloud around the joint
       • TIG (tungsten inert gas)
         • Form of arc welding using tungsten electrode ans has a inert gas like MIG
       • Arc
         • Generated sufficient heat to melt the joint edge by creating a electric current through a gap between the materials being joined and the filler rod (electrode). The electrode is coated in a flux which when melted prevents the joint area becoming oxidised.
     • Soldering
     • Riveting
       • Pop rivet- with a rivet gun
       • Solid rivet
     • Brazing
       • Materials are cleaned, parts are clamped together. When the brazing spelter melts it fills the joint between the metals through capillary action.
     • Crimping
       • Joining two thin sheets of metal together, e.g. drinks can
     • Press froming
     • Sintering
       • Powder compacted into die by punch and then heated to promote bonding of material
     • Investment casting
   • Plastics
     • Injection Moulding
     • Vacuum forming
     • Injection Blow Moulding
     • Rotational Moulding
     • Adhesives
       • PVA
       • Tensol
       • Epoxy resin
     • Ultrasonic welding
     • Plastic welding
     • Compression moulding
     • Line bending
     • Calendering rubber
   • Temporary joining methods
     • Nuts and bolts
     • Self tapping screws
     • Knock-down fittings p100
       • Cam fittings
       • Captive nuts
       • Corner blocks

2. Plastics

   • Thermoplastics
     • LDPE
       • Ligtweight, good chemical resistance
       • Detergent bottles, toys and carrier bags
     • HDPE
       • Creates, bottles, buckets and bowls
       • High density, good stiffness, good chemical resistance
     • Polypropylene
       • Lightweight, food safe, good impact resistance
       • Kitchen products, medical equipment
     • HIP's
       • Good impact resistance, good strength, lightweight
       • Toys and refrigerator linning
     • Acrylic (PMMA)
       • Food safe, tough, hard, durable, easily machined
       • Light units, illuminating signs
     • Polysterene
       • Lightweight, rigid, low impact strength
       • Packaging, disposable cups/plates and containers
     • ABS
       • High impact strength, good scratch resistance
       • Kitchen products, safety helmets, toys
   • Thermoseting
     • Epoxy resins (araldite)
       • High strength when reinforced with fibres (GRP), good chemical and wear resistance
       • Surface coatings, encapsulation on electronic components, adhesives
     • Urea formaldhyde
       • Rigid, hard, good strength, brittle, good eletrical insulator.
       • Electrical fittings, adhesives
     • Melamine formaldhyde
       • Rigid, good strength and hardness, scratch resistance
       • Tableware, decorative laminates fro work surfaces
     • Polyester resin
       • Rigid, brittle, good heat and chemical resistance
       • Casting, used in reinforced plastics