wasting metals

wasting is the removal of material; by cutting, the waste can often be recycled, the curled waste from turning is known as swarf

METHODS

milling - uses a high speed steel or carbide head. they can cut complex 3D forms on multiple axes, there are many different heads that have different roles, such as drills for holes, slitting saws for slots, dovetails, corners, balls, fly cutters for planes and reamers to enlarge holes to an exact size. complex milling Is used to make accurate machine parts, CNC controls and multi-tooled cutter are quicker and more precise. some mills make chamfers which break corners at 45° to make a safe edge, slots make accurate profiles and milling is suitable for small and large scale production

turning - a lathe is used to turn metal, a chuck can be used with a tail stock for longer pieces’ stability. a billet is fed and the cutting tools (made from high-speed steel and silicon carbide) shape and waste the metal, CNC is used for batch and production lines, whereas hand turning is often used for one-off production. CNC turning can utilise multi-head tools that change automatically increasing efficiency. also CAD means repeatability is high and pieces can be made quickly. some turning tools are facers for a flat edge, tapers, drilling, parallel turning for insets, parting for separating a finished piece and knurling for an easy to grip texture

flame cutting - flame cutting uses oxyacetylene gas to create a 3500°C flame, the oxygen makes the flame stronger and doesn’t require electricity, this is used for low carbon steel but is quite inaccurate

plasma cutting - plasma cutting uses a charged/ionised gases that conduct electricity at high temperatures, the temperatures can reach 28,000°C and it used to cut steel accurately. shield gas is used to avoid oxidation and can cut up to 15cm thick metal

laser cutting - this uses a high powered laser on a bed, the focus, speed and power can be changed to cut most metals, the laser beam is very accurate creating a fine finish, metal laser cutters also use CAD. laser cutting is used on sheets and can’t cut very thick metal. laser cutting can use a lot of energy and is used for big batch runs

punching and stamping - stamping is used on metal sheets to create slots, blanking creates cut out parts for processing using force, this can be controlled using CNC machines for sheets up to 6mm, the punch is on top and the die below, the slug is the pieces that are removed and this is often used for dishwashers and washing machines