Enhancing Printability of Pure Copper through Tailored Scan Strategies in Blue-laser Powder Bed Fusion

Terrol Wilson, University of Nebraska-Lincoln

Document Type Thesis

Copyright 2025, Terrol Wilson. Used by permission

Abstract

Additive Manufacturing (AM) is emerging as an alternative to classical manufacturing techniques; it involves a layer wise building strategy to create 3D structures with either polymers or metals. Laser powder bed fusion (LPBF) is the leading technique used worldwide in relation to the creation of AM metal structures. Copper is commonly used across several sectors in thermal management products such as cooling systems, heat exchanges to name few, due to its thermal properties such as thermal conductivity of 401 W/m·K. Generally, LPBF is conducted with the use of a Near Infrared (NIR) Laser with wavelength range (1060 -1080) nm, however copper reflects approximately 95% of light when irradiated with NIR lasers thus leading to high porosity in printed parts. However, recent research has been focused on visible wavelength (400-700) nm lasers that can be absorbed at a higher percentage when copper is irradiated. Hence this research utilizes a blue wavelength (443 nm) laser to explore potential parameters that can be used to create copper structures with high relative density. Scan strategy describes the laser path taken during printing, in this research we implemented various forms of scan strategies including alternate layer 90^o and 67^o raster scan rotation as a method to analyze their effects on AM part quality. In addition, thermal management strategies such as beam wobbling and preheating were conducted to optimize the LPBF process. Furthermore, the findings and processing parameters explored in this research can provide insight related to processing pure copper with LPBF.

Advisor: Qilin Guo