A comprehensive investigation of abrasive barrel finishing on hardness and manufacturability of laser-based powder bed fusion hollow components

Abstract

One of the main issues of laser-based powder bed fusion (LB-PBF) parts is surface quality and dimensional deviations, which require post-processing. Conventional post-processing such as turning and milling cannot machine internal surfaces and therefore is not suitable for hollow components. In this paper, Ti–6Al–4 V components with different hollow shapes were printed by LB-PBF and post-processed by centrifugal barrel finishing (CBF). Samples were printed based on Taguchi L18 design of experiments (DoE) on the (L18: 21 × 33) matrix and polished in abrasive solution by porcelain triangular media 2 × 2 mm. The effect of process parameters including rotation direction, speed, time and volumetric percentage of abrasive on hardness and manufacturability, including surface quality, material removal rate (MRR) and dimensional deviation, are discussed. The novelty of this work is the application of this process to clean both the internal and external surfaces of LB-PBF parts, where previously it has only been investigated for external surfaces. This paper scrutinized the performance of the CBF on internal geometries, and it was shown for the size of the investigated components, the hexagonal hollow achieved the highest maximum removal rate over the square and circular hollows. In addition, the effect of CBF on plastic deformation and microstructural characterization has been investigated to find the effect of this process on work hardening. The results of this study also show that the rotational speed and the volumetric percentage of the abrasive directly drive the MRR. A higher rotational speed increases the slope of the sliding path and the sliding speed between printed parts and abrasive media, which causes higher cutting and grinding, MRR and media wear rate.

Mechanical Properties of AISI 316L Lattice Structures via Laser Powder Bed Fusion as a Function of Unit Cell Features

“…This kind of surface finish will promote early failure due to the fact of stress concentrators and crack initiators encountered on the surface. Therefore, the application of postprocessing techniques, such as machining [ 8 ], chemical polishing [ 9 ], or abrasive finishing [ 10 ], are needed to enhance the final geometry and mechanical performance of the produced parts.…”

Polishing of metal 3D printed parts with complex geometry: Visualizing the influence on geometrical features using centrifugal disk finishing

“…Prolonged contact with the abrasives in the form of a longer processing time results in the same effect [ 14 , 16 , 17 ], up to a limit [ 15 ]. Higher speeds are also associated with higher material removal rates, due to higher forces being applied to the workpieces [ 16 , 18 , 19 ]. The fill level of the container with polishing media was shown to have a negligible effect on material removal rates, higher load levels decreased the chance of contact between the abrasives and workpiece [ 14 , 18 ].…”

“…Higher speeds are also associated with higher material removal rates, due to higher forces being applied to the workpieces [ 16 , 18 , 19 ]. The fill level of the container with polishing media was shown to have a negligible effect on material removal rates, higher load levels decreased the chance of contact between the abrasives and workpiece [ 14 , 18 ]. The advantages of MF processes are that the process is hands-off, it can process multiple parts at once, and it can be customized to the type of metal and surface finish required.…”

Assessment of Machining of Hastelloy Using WEDM by a Multi-Objective Approach

“…Researchers can improve the yield of the machining process by using the Grey fuzzy method, which is very useful in developing accurate and efficient machining techniques. Optimization plays a major role in any kind of manufacturing processes, and further development of these techniques may lead to advanced manufacturing methods, such as additive manufacturing and processing techniques [22][23][24][25][26]. The Grey theory can be used to improve the performance of various decision-making tools.…”