Increasing productivity for laser powder bed fusion of Ti–6Al–4V parts through increased layer thickness

Additive manufacturing (AM) has enabled the development of numerous innovative products that are now commercially available. However, its adoption for producing components traditionally manufactured using conventional methods remains limited. A significant barrier to broader industrial implementation of AM techniques, such as laser powder bed fusion (L-PBF), is their comparatively lower productivity rates, directly impacting manufacturing costs and, consequently, the adoption rate of L-PBF technology. This study examines whether modifications to L-PBF process parameters can mitigate cost-related constraints associated with production rates whilst maintaining the material properties of Ti–6Al–4V produced at standard layer thicknesses. Whilst existing research on Ti–6Al–4V processing has primarily focussed on microstructural and mechanical properties, there has been limited investigation into productivity enhancements through increased layer thicknesses beyond the conventional range of 25–60 µm. To address this gap, a series of experiments were conducted to evaluate the feasibility of increasing the layer thickness to 120 µm by modifying key process parameters, including laser power, scan speed, and hatch distance. The L-PBF parameters were varied through a response surface methodology (RSM) design of experiments (DOE) to obtain, via statistical analysis, the optimum parameters for Ti–6Al–4V at 120 μm layer thicknesses. The findings demonstrate that L-PBF systems can sustain a stable processing environment whilst operating at higher throughput levels. This was established through experimental results that show the DOE process identifying L-PBF parameters that can produce acceptable bulk density at an increased layer thickness of 120 μm. Furthermore, mechanical testing revealed that specimens printed at 120 µm exhibited comparable mechanical properties to those fabricated at the standard 60 µm thickness, achieving an average ultimate tensile strength (UTS) of 1291 MPa and 1292 MPa, and a median elongation of 9.22% and 9.74%, respectively. Post-processing techniques, including vacuum heat treatment and hot isostatic pressing (HIP), further enhanced mechanical properties, ensuring that all 120 µm specimens met or exceeded ASTM F3001-14 (Designation: F3001-14 Standard specification for additive manufacturing titanium–6 aluminum–4 vanadium ELI (extra low interstitial) with powder bed fusion. 2014. https://doi.org/10.1520/F3001-14) requirements. This study highlights the potential for increasing L-PBF productivity without compromising material performance, offering a pathway towards more cost-effective AM production for aerospace and biomedical applications.