What kind of metal powder is suitable for 3D printing? How to prepare such metal powder
The widely used printing consumables for 3D printing mainly include four types in the form: liquid photosensitive resin material, thin material, low melting point wire material, and powder material; in terms of composition, it covers almost all kinds of materials in current production and life, including plastics, resin, wax, and other polymer materials, metal and alloy materials, ceramic materials, etc. Among them, metal powder 3D printing is undoubtedly at the forefront and has development potential.
Currently, the 3D printing metal powder materials include stainless steel, die steel, nickel alloy, titanium alloy, cobalt-chromium alloy, aluminum alloy, and bronze alloy.
So, how do you prepare metal powder suitable for 3D printing?
1. Argon atomization method
The argon atomization method is a pulverizing method that uses a fast-flowing argon gas flow to influence the metal liquid, crushing it into fine particles and then condensing it into a solid powder.
2. Plasma atomization
The pulverizing process of the plasma atomization method can be described as the solid raw materials, such as rods and wires, being directly sent to the high-temperature zone of the plasma focus through a particular feeding device. The raw materials are rapidly melted or vaporized, or decomposed by the thermal reaction to synthesize, atomize Metal, or ceramic powder materials of various materials of ultra-fine/nano level are prepared. Then the droplets are rapidly cooled and solidified into spherical powder under the action of surface tension. The prepared powder materials are cooled, deposited in the atomization tower system, and collected centrally. The atomized exhaust gas is filtered and purified, and then discharged.
3. Radiofrequency plasma spheroidization
The irregularly shaped raw material powder is sprayed into the plasma torch through the powder feeder with the carrier gas (argon). The powder particles absorb a lot of heat in the high-temperature plasma, and the surface melts rapidly, entering the reactor at a very high speed. Rapid cooling in an inert atmosphere, under the action of surface tension, cooling and solidification into spherical powder, and then entering the receiving chamber for collection.
The metal powder produced in this way has the following advantages:
High sphericity, smooth surface, good fluidity, and high bulk density, so the powder spreading uniformity is good, and the printed product has high density;
Small powder particle size, narrow particle size distribution, low oxygen content, little/no spheroidization and agglomeration during printing, good melting effect, high product surface finish, and the consistency and uniformity of printing can be fully guaranteed;
There are no hollow powders and satellite powders, and there will be no defects such as air gaps, entrapment and precipitation pores, and cracks caused by hollow spheres during the printing process.
