“When making parts for aeronautics, medical devices and other complex applications, quality is fundamental…any gains in output that compromise the safety or utility of the part aren’t gains at all,” explains Dr. Zach Murphree, Velo3D vice president, in a blog that discusses the technical hurdles in jumping from one to two lasers in a metal-AM build. In building a single large aerospace part, for example, scan-field alignment presents a particular concern in a multiple-laser setup, whereas for small medical parts, the lasers can be tasked with each building separate parts.

“With larger parts that take up most of the build plate, the lasers must work in concert, and, like circus performers catching each other in mid-air, a slight misalignment can have big consequences,” he offers in the blog. “In engineering terms, this means that each scanning system has to be aligned to the other with less than 50-micron (1/20th of a millimeter,―thinner than a human hair) difference everywhere on the build plate.

“The thermal state of the system also becomes an important variable,” he adds, introducing another complication. 

Even a 15 C change in the chamber temperature can change the distance between the scan head and build plane by more than 100 microns.

“Depending on the angle of incidence in the overlap region,” Murphree writes, “this temperature change, by itself, can invalidate the calibration.” 

Murphree sees laser scheduling and pathing as solutions here, and also as critical to realizing the benefits of multi-laser systems. ”But,” he cautions, “engineers also must examine how the laser soot effects the scheduling and how well the lasers coordinate their efforts on contour and core for larger parts.”

And the complexities grow from here. So much to think about…but it seems that the newest technology is putting such thinking into action.

See also: SLM Solutions NA, Inc.

Technologies:

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