Sequential Solidification of Metal Powder by a Scanning Microwave Applicator

This study examines the fundamental feasibility of sequential metal-powder solidification by localized microwave-heating (LMH) provided by a scanning, all-solid-state microwave applicator. This continuous process is considered for the additive manufacturing (AM) and 3D printing (3DP) applications of metal parts. In previous studies, we employed LMH for the incremental solidification of small batches of metal powder in a stepwise vertical manner. Here, we study a continuous lateral LMH process, layer by layer, in a fashion similar to laser scanning in powder beds, as performed in common laser-based AM systems. LMH solidification at scanning rates of similar to 1 mm(3)/s is obtained in bronze powder using similar to 0.25-kW microwave power. The effect is studied here by LMH scanning in one lateral dimension (similar to 20-mm long) in layers, each of similar to 1-4 mm thickness and similar to 2-4 mm width (mechanically confined). Imperfect solid bars of similar to 20x4x5 mm(3) are obtained with rough surfaces. Their joining in an L shape is also demonstrated. The experimental solidified products are tested, and their hardness and density properties are found to be comparable to laser-based AM products. The capabilities and limitations of the LMH scanning concept for metal-powder solidification are evaluated. The potential feasibility of a solid-state LMH-AM technology is discussed.

Automated summary

This study investigates the feasibility of using localized microwave-heating (LMH) for sequential metal-powder solidification in additive manufacturing (AM) and 3D printing applications. The study focuses on a continuous lateral LMH process, similar to laser scanning in powder beds. LMH solidification in bronze powder is achieved at a scanning rate of approximately 1 mm³/s using 0.25 kW microwave power. The study evaluates the capabilities and limitations of the LMH scanning concept for metal-powder solidification and discusses the potential feasibility of a solid-state LMH-AM technology.