3D Printing Breakthrough Eliminates Defects for Reliable Metal Parts
By Carolyn Mathas
A team of engineers at the University of Wisconsin–Madison has successfully mitigated three common defects in metal parts—pores, rough surfaces, and large splatters—using a prominent additive manufacturing technique called laser powder bed fusion. They discovered the mechanisms behind these defects and identified processing conditions to reduce them, publishing their findings in the International Journal of Machine Tools and Manufacture.
Until now, research had primarily focused on reducing one type of defect at a time, with the reduction of others requiring different techniques. The UW–Madison team developed an innovative approach to address all three defects simultaneously. This approach also enabled the production of parts at a faster rate without compromising quality. Industries such as aerospace, medical, and energy are eager to use 3D printing to produce complex-shaped metal parts. However, conventional methods have struggled with defects like pores (voids), rough surfaces, and large spatters, which compromise the reliability and durability of finished parts. As a result, 3D-printed metal parts are rarely used in critical applications where failure is not an option.
Laser powder bed fusion employs a high-energy laser beam to melt and fuse thin layers of metal powder, building a part layer by layer from the bottom up. The UW–Madison team achieved their breakthrough by using a ring-shaped laser beam, provided by the laser company nLight, instead of the traditional Gaussian-shaped beam.
To observe material behavior during printing, researchers utilized the Advanced Photon Source, an ultra-bright, high-energy synchrotron X-ray user facility at Argonne National Laboratory. Using high-speed synchrotron X-ray imaging, theoretical analysis, and numerical simulation, they revealed defect mitigation mechanisms that reduce instabilities in the laser powder bed fusion process.
The team also demonstrated that the ring-shaped beam could drill deeper into the material without causing instabilities, enabling the printing of thicker layers. This advancement increases manufacturing productivity while maintaining quality.
