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Wastage

Wastage is the process of cutting away material with tools and equipment. Good design can minimise the amount of wastage produced. For electronic and mechanical systems, there are several wastage processes available.

• Laser cutter - can use computer aided design (CAD) programs to draw and then cut any shape out of wood, plastic or circuit board and can also cut out intricate shapes, such as plastic gears
• Guillotine - printed circuit boards (PCBs) should be cut into shape before any components are added, and the most accurate way to do this is with a guillotine, which uses a sharp blade to chop through the sheet
• Drilling - holes can be drilled through a PCB to provide an accurate place to add components either by hand or using a computer numerical controlled (CNC) router
• Computer numerical controlled (CNC) router - for the cutting, engraving and drilling of PCBs, the cutting blade works by spinning and moving along a pre-programmed route quickly and accurately

Addition

Addition is the process of adding on material.

• Soldering - can be done by hand or machine, where solder is heated until liquid and then added to the components and PCB where it cools and sets, allowing electricity to flow from one point to another
• Welding - by melting the work material as well as the filler or welding rod, it creates a strong bond that can join metals together in mechanical systems
  • arc welding is used for manufacturing products with mild steel, eg trailers
  • mig welding is used for light steel, eg in car bodywork
  • spot welding is used to attach panels of metal together
  • gas welding is used for joining pipes
• 3D printing - can be used to build up or cover areas that need protecting, producing very little wastage, but it is time-consuming and expensive