By Gary Wagner, General Manager, Ophir (U.S.)
To print a metal part, metal powder is drawn on the build area to an exacting thickness while a focused laser beam heats the metal powder to the correct temperature; this fuses the powder.
If the laser power is too low or not applied long enough, the grains of powder do not melt properly; the metal becomes porous and, therefore, weaker. If too much laser power is used or the laser is applied longer than necessary, the laser will drill into the fused powder, reducing the density of the structure. If the focused spot location is before or behind the build plane, or the distribution of the laser power is not optimized, inadequate melting of the metal powder will result. All of these conditions leave you with a part that is not metallurgically correct.
Quality 3D laser printed processes require a laser delivering the correct amount of power, distributed correctly and focused at the correct location. To ensure consistent and structurally sound parts, these parameters should be directly measured before and after any critical part is made.