Metal powders have been used in everything from explosives to paints. Common uses are:
- Sintered ferrous powders used for gears, rockers, and myriads of automotive engine components, and also used for door locks, knobs, brackets, etc.
- Paints of all descriptions, including copper anti-fouling paints, 'cold gal' zinc paints, aluminium style paints, etc.
- Copper and brass used in carbon brushes for electric motors, brake pads, and friction materials.
- Metal spraying, such as early oxy-acetylene powder spraying process, used to reclaim worn parts. This has been superseded by HVOF coating and plasma spraying, commonly used for hard facing and building up of worn parts.
- Additive manufacturing, such as 3D printing and cold spray technology.
- 3D printing is rapidly becoming the technology of the future. Everything from hip prosthesis to aircraft parts are being produced from titanium, resulting in parts equivalent to forgings in strength.
- With cold spray technology, it is possible to use a wide spectrum of metal powders and alloys, resulting in the reclaiming of aircraft parts, and in the direct manufacture of parts and components previously not possible, or economically viable. Other uses being developed are: the cold spraying of undersea cables to prevent destructive attack by limpets and other crustaceans; the coating of temperature probes and electrodes in the aluminium smelter industry to extend service life.
Specialized Aximill Application
Presently the variety of powdered metals is limited, but with Aximill, the range can be extended to satisfy the needs of niche customers. In the aluminium industry, for instance, there are dozens of alloys for the aircraft industry alone, yet only a few of these are available in powder form. Titanium, magnesium, copper, alloys of iron and steel, ie. Invar, are in high demand, but are difficult to source, and the development of additive manufacturing is limited by the expense of these powders.
- Small runs of these different alloys can be readily manufactured and stocked at much lower cost than by current technology.
- Only small volumes of purging gas are needed with a 250 model, and as little as one kilogram can be economically milled at a time.
- One machine may be used for a variety of metals, with minimal cleaning required. To prevent cross contamination, additional rotor housings and rotors can be assigned to specific alloys.
- Waste materials can be utilised as feed stock:
- Clean manufacturing waste ie. lathe swarf or milling chips, can be used directly as feed stock. Note, if these materials are unavailable, the feed stock has to be milled conventionally to a size that allows Aximill micronisation, ie. similar to lathe swarf or milling chips.
- Copper wire chopped to 10 mm lengths makes an ideal feed stock. In the case of insulated cable, the wire is easily separated from the casing by passing through the Aximill and an air separator. The wire is then passed through the Aximill again with shielding gas, and higher speed, to produce the metal powder.