Impact of Pulsed Laser Parameters and Scanning Pattern on the Properties of Thin-Walled Parts Manufactured Using Laser Metal Deposition

The quality of parts manufactured using laser metal deposition (LMD), similar to other additive manufacturing methods, is influenced by processing parameters. Such parameters determine geometric stability, favorable microstructures, and good mechanical properties. This study aimed to investigate the effects of pulsed laser parameters (duty cycle and pulse frequency) and scanning patterns (unidirectional and bidirectional patterns) on the properties of parts fabricated using LMD. Results show that the properties of the LMD-fabricated parts are obviously influenced by pulsed laser parameters and scanning patterns. Using the unidirectional scanning pattern in both pulsed laser parameters enhances the properties of the thin-walled parts prepared using LMD. An increase in duty cycle can improve geometric stability, increase grain size, and reduce microhardness. Furthermore, the geometric stability does not vary considerably with the use of different frequencies, but the microstructure of fabricated parts shows various grain sizes with different pulse frequencies. In addition, the microhardness increases as the frequency increases from 13.33 to 50 Hz. In general, the influence of the duty cycle on geometric properties is greater than that of frequency. Meanwhile, the impact of frequency on microhardness is greater than that of the duty cycle.