Numerical investigation of laser powder bed fusion of glass

Abstract

Additive manufacturing of glass using laser powder bed fusion has been recently developed, demonstrating its potential to be applied in small scale applications such as flow reactors for the chemical engineering and pharmaceutical manufacturing industries. While previous research demonstrated that complex 3-dimensional shapes can be manufactured, built parts are often brittle, exhibit high porosity and lack transparency. This study employs a transient, heat transfer finite element analysis to shed light on the thermal response of laser—glass powder bed interaction and the impact of processing parameters. Through this understanding, the research seeks to identify practical strategies that can be employed to improve the quality and properties of the built parts. Bulk solid and powder soda lime silica glass properties are used as input in the model, while the laser heat flux and scan strategy, conversion of powder feedstock to bulk solid glass and heat losses from convection and radiation effects are introduced in the model through Fortran coding. The study showed that effective powder consolidation, resulting in well-defined geometrical features, is achieved for temperatures near the glass melting point. Additionally, uniform consolidation depths and widths can be achieved by increasing laser power, elevating substrate temperature and reducing scan speed within certain limits, whilst ensuring hatch spacing is below the corresponding single scan track width for unidirectional adjacent laser trajectories.