Moulding and joining

• Moulding


  The process of shaping materials, especially plastics and metals
• Joining


  The process of connecting materials, especially plastics and metals
• Vacuum Forming


  1. A mould is put onto the vacuum bed

  2. Thermoforming plastic sheets or films (e.g. polypropylene or HIPS) are clamped above the vacuum bed and heated until they go soft

  3. The vacuum bed is lifted close to the heated plastic

  4. The air is sucked out from under the plastic, creating a vacuum. The air pressure from outside the mould then forces the plastic onto the mould

  5. The moulded plastic is cooled and the vacuum bed lowered
• Soldering


  A relatively low temperature process that involves melting solder (made from tin and other metals) onto the components to be joined - this sticks them together when it cools and solidifies
• Soldering


  • Uses a soldering iron or blow torch
• Welding


  The strongest method of joining metal, using a very high temperature from a gas (oxyacetylene) torch, or an electric-arc welder to melt the edges of the joint so that they flow together
• Welding


  1. Welding uses a welding rod that is melted at the same time to fill the joint

  2. Metal sheets can be spot welded - this is where the metal sheets are melted and joined at a number of separate spots along their edge

  3. Welding can be used to fill in thinned metal or small gaps
• Brazing


  A higher temperature process that often uses brass spelter as the joining material, much stronger than soldering
• Brazing


  • Uses a gas brazing torch, a blow torch, or a brazing attachment for an electric-arc welder to heat the joint
• Welding masks are worn to protect your eyes from the bright light and UV radiation from the welding arc, and to protect your face from heat and sparks
• Polymers can be welded too