An important 3D printing material -- metal powder

          As the most important link of the 3D printing industry chain of metal parts, 3D printing metal powder is also the biggest value. At the 2013 world 3D printing technology industry conference, the world's leading experts in 3D printing industry have given a clear definition of 3D printing metal powder, that is, the size of less than 1mm of metal particles group. includes single metal powders, alloy powders, and some refractory compound powders with metallic properties.

          Currently, 3d-printed metal powder materials include cobalt-chromium alloy, stainless steel, industrial steel, bronze alloy, titanium alloy and nickel-aluminum alloy. However, in addition to good plasticity, 3D printed metal powder must also meet the requirements of fine particle size, narrow particle size distribution, high sphericity, good fluidity and high loose packing density.

          In order to further demonstrate the effect of 3D printed metal powders on products. the author used selective laser sintering (SLS) to print two different kinds of stainless steel powder, and found that there were significant differences in the prepared products.

          A German manufacturer of stainless steel powder printing sample surface gloss, small shrinkage, not easy to deformation, mechanical stability. and the printing sample of the stainless steel powder of some domestic manufacturer is far inferior to the former.Therefore, the microstructure of two different stainless steel powders was analyzed.

          The above is the microstructure of a stainless steel powder made in Germany. It can be seen from the figure that the powder particles have good sphericity and particle size distribution is within the range of 11.2~63.6 nm. the following figure shows the microstructure of the stainless steel powder produced by a domestic manufacturer. It can be seen that the particles are irregular and small in size.

          The above research shows that the metal powder of 3D printing consumables should meet the requirements of small particle size, narrow particle size distribution, high sphericity, good fluidity and high loose packing density. Therefore, in order to obtain 3D printed products with excellent performance, it is necessary to seek for an efficient method of metal powder preparation.