Monitoring of laser powder bed fusion

The successful applicant is expected to partake in, and follow up on two approved and funded projects on process monitoring of laser powder bed fusion:

• (1) MultiPLICITY: Off-axis camera monitoring and resulting control of laser powder bed fusion with multiple lasers. 
• (2) MuSIC: Using multiple sensing/monitoring techniques on single laser powder bed fusion, including on-axis optical methods as well as acoustic emissions, and using all the data concurrently for improved quality control. In this project, you will collaborate with (and possibly mentor) a PhD student.

Online monitoring of laser powder bed fusion (LPBF) is typically performed using coaxial (viewing along the laser trajectory) melt pool cameras, coaxial photodiodes, off-axis cameras, or some combination thereof. The monitoring information is typically processed individually, even if multiple information streams are available. Unfortunately, there is a lot of noise and uncertainty related to process monitoring of LPBF, and none of the individual monitoring techniques have proven to have a highly accurate correlation with the processing conditions. Such a high fidelity correlation is required for online process monitoring to move towards online process control, which is the ultimate goals. 

On the other hand, multi-laser systems have multiple regions of interest and another layer of complexity is added through possible laser-laser interactions. Process monitoring of such systems must overcome these challenges, but could also benefit from the presence of a second laser in process control.

These projects build on the existing expertise of the AM research group in the use of monitoring for improved insight into the process, as in the following publication:  https://www.sciencedirect.com/science/article/pii/S2214860421000889 (paper available upon request).