Melt Pool in 3D Metal Printing

Like welding, the idea of melt pool is also used in 3D metal printing.
An area where the metal powder was melted by laser and liquidated is called melt pool. This melt pool bonds upper layer and lower layer (Fig.1)

Unstable melt pool causes welding defects. Fig2 shows cross section of melt pool, which laser scanned on the top layer in one line. We can see that there is a defect in (b).

The shapes of the melt pool changes according to parameters like laser power and scan speed.
It is important to fabricate components free from detects, and at the same time improve productivity by arranging the metal powder and adjusting parameters.