Metal Additive Manufacturing Laser Power Assessment

Summary

In laser powder bed fusion (LPBF) additive manufacturing the laser power levels are typically from 50 W to 1 kW. Power measurements in this range are typically straightforward, but other factors such as calibration period, laser degradation rate, environmental influences, and measurement protocols have practical effects on the accurate delivery of laser power. We are performing a “round-robin” style measurement to assess the real-world performance of laser power delivery to AM machines on shop floors, in government laboratories, and within university research facilities.

Description

A calibrated (U=1.2 %, k=2) power meter was taken to a variety of AM locations (industry, academic, government, DoD) to anonymously assess the accuracy with which these institutions know the laser power being delivered to the workpiece. At each site, the LPBF operator was asked to use the AM system to deliver approximately 5 prescribed laser powers and measure them via whatever is their customary means. Then the NIST-calibrated power meter was placed, and the operator again asked to deliver the same five powers. Anonymized results are being compiled to assess the accuracy with which such AM systems are typically able to deliver and measure laser power to the powder bed. Results are being used to recommend best practices and identify reasonable tolerances which can be expected by more demanding build designs.