What is the impact of 3D printing powder on 3D printing

3D printing technology is a new type of printing technology, with the outstanding advantage of being able to directly generate parts of any shape from computer graphics data without the need for mechanical processing or any molds, greatly shortening the product development cycle, improving productivity, and reducing production costs. Today we will talk about the important material used in 3D metal printing -3D printing powder. At present, there is no doubt that 3D printing powder has potential. The types of metal powder materials used for 3D printing include stainless steel, mold steel, nickel alloy, titanium alloy, cobalt chromium alloy, aluminum alloy, and bronze alloy.
During the process of producing 3D printing powder, particles of different shapes, such as spherical, elliptical, porous sponge, tree shaped, etc., may appear due to different requirements and production methods. The fluidity and porosity of the powder will vary with the shape, and have different effects on the printing of the product. Generally, spherical or elliptical powders have good flowability, so the powder supply system of 3D printers will not block due to poor circulation during printing. And it is easy to lay flat into a thin layer. Make the 3D printed object have higher accuracy and the various parts will be more uniform. For current technology, spherical shape is undoubtedly a better choice. However, spherical powder printed products are not as good as other shaped products due to the large gap. If you want better quality, you need to make the diameter of the 3D printing powder smaller.
Usually, the diameter of 3D printing powder is made smaller, because if the diameter of the powder is smaller, sintering will be better, and the driving force of sintering will also be increased. When stacking, not only is the diameter smaller, but the gap will also be smaller, so that the quality and strength of the product can be guaranteed. However, the diameter of the powder should not be as small as possible, as if the diameter of the powder is too fine, it may cause "spheroidization" during the sintering process, resulting in uneven powder spreading and affecting printing accuracy.
In addition, the oxygen and nitrogen content of 3D printing powder also needs to be strictly controlled. At present, the powder preparation technology for metal 3D printing is mainly based on atomization method, which has a large specific surface area and is easy to oxidize. In special application fields such as aerospace, the requirements for this indicator are more stringent, such as the oxygen content of high-temperature alloy powder being 0.006% -0.018%, titanium alloy powder being 0.007% -0.013%, and stainless steel powder being 0.010% -0.025%.
The selection of powder particle size for 3D printing is mainly based on metal printers with different energy sources. Printers powered by lasers, due to their small focusing spot and easy melting of fine powder, are suitable for using 15-53m powder as consumables. The powder supply method is layer by layer powder spreading; The powder spreading printer powered by electron beam has a slightly thicker focal spot, which is more suitable for melting coarse powder, mainly suitable for using 53-105m coarse powder; For coaxial powder feeding printers, powder with a particle size of 105-150m can be used as consumables