Complex 3D Parts Research Articles

Generalized SmartScan: An Intelligent LPBF Scan Sequence Optimization Approach for Reduced Residual Stress and Distortion in 3D Part Geometries

Abstract Laser powder bed fusion (LPBF) is an additive manufacturing technique that is gaining popularity for producing metallic parts in various industries. However, parts produced by LPBF are prone to residual stress, deformation, cracks and other quality defects due to uneven temperature distribution during the LPBF process. To address this issue, in prior work, the authors have proposed SmartScan, a method for determining laser scan sequence in LPBF using an intelligent (i.e., model-based and optimization-driven) approach, rather than using heuristics, and applied it to simple 2D geometries. This paper presents a generalized SmartScan methodology that is applicable to arbitrary 3D geometries. This is achieved by: (1) expanding the thermal model and optimization approach used in SmartScan to multiple layers; (2) enabling SmartScan to process shapes with arbitrary contours and infill patterns within each layer; (3) providing the optimization in SmartScan with a balance of exploration and exploitation to make it less myopic; and (4) improving SmartScan’s computational efficiency via model order reduction using singular value decomposition. Sample 3D test artifacts are simulated and printed using SmartScan in comparison with common heuristic scan sequences. Reductions of up to 92% in temperature inhomogeneity, 86% in residual stress, 24% in maximum deformation and 50% in geometric inaccuracy were observed using SmartScan. An approach for using SmartScan for printing complex 3D parts in practice, by integrating it as a plug-in to a commercial slicing software, was also demonstrated experimentally, along with its benefits in significantly improving printed part quality.

Powder coarsening mechanisms of Ti-6Al-4 V with multiple build cycles in laser powder bed fusion

Laser powder bed fusion (LPBF) is an additive manufacturing process which can produce complex 3D parts from digital models. The performance of parts fabricated by LPBF is largely dependent on the characteristics of the powder feedstock, in particular, the particle size distribution. The coarsening of powder particles may limit the potential for reusing powder in further builds, as consistency in powder quality is crucial for ensuring consistent parts performance when using reused powder, especially in aerospace applications. However, there is a lack of systematic understanding regarding the causes and nature of powder coarsening in LPBF. In this work, the characteristics of powder samples from different locations in the build chamber during LPBF were studied to understand the particle size evolution and determine the origin of coarsening, which has not been previously reported. Meanwhile, powder coarsening was found to have a detrimental effect on the relative density and surface quality of as-built parts, highlighting the importance of exploring the mechanisms of powder coarsening and finding ways to control it in LPBF. The relationship between powder in key locations in the build chamber and its effect on powder coarsening has been established. Layer thickness is identified as a critical factor in causing powder coarsening due to the fine powder size characteristic in the powder bed. Spatter, in its various forms, plays a direct or indirect role in powder coarsening. Sintered powders resulting from spatter and the laser scanning borders of as-built parts were observed to contribute to the powder coarsening. Therefore, three main mechanisms (layer thickness, spatter, sintered powder) associated with the powder coarsening are therefore proposed. This work provides insight and potential solutions to control powder coarsening and maintain consistent parts performance.

Optical manipulation of ultrashort laser pulses for applications in challenging environments

Over the last few years, high throughput ultrashort-pulse laser sources have become increasingly affordable. This facilitated the emergence of many applications that require sub-micron precision material modification. Processes have been demonstrated in applications including micro-structuring semiconductor chips, manufacturing complex 3D parts or inscribing optical materials for data storage. Furthermore, recent progress in techniques for the optical manipulation of ultrashort laser pulses opened up new avenues in applications for challenging environments such as those involving high energy physics or particle beam radiotherapy. These applications require high-resolution 3D structures to be produced in radiation tolerant materials, to make particle sensors with the required sensitivity and resolution. For such processes, accurate spatial and temporal structuring and manipulating of optical parameters such as polarization, wavefront and intensity of laser beams, is essential. This paper presents recent results in advanced optical manipulation including the induction of helical or longitudinal fields at the focus. The resulting laser material coupling interactions are characterized and their suitability for making particle sensors from radiation hard materials considered.

Sustainable optimization of micro-milling machining parameters considering reliability assessment

Micro-milling is a crucial machining technology used for complex and precise 3D parts and plays a crucial role in modern manufacturing. In this work, to comprehensively evaluate the safety, economic feasibility, and environmental friendliness of the micro-milling processing process, a sustainable optimization framework including reliability assessment is designed. Firstly, modeling and experimental measurements are conducted on sustainability evaluation standards such as tool life, machining process, machining surface quality, material removal rate, machining cost, and carbon emissions. Subsequently, the influence of physical information such as observation/measurement data and processing errors is analyzed, and a Bayesian update method is proposed and integrated with neural networks to precisely inversion the probability distribution of parameters within the optimization cycle under conditions of uncertainty. Finally, combined with the overall sustainability indicators, the multi-objective optimization process is refined through penalty functions and weighting methods, aiming to achieve the best balance between processing performance and sustainability. The simulation and experimental results have verified the superiority of the developed framework, and the present method provides valuable guidance for sustainable micromanufacturing.

Fabrication, Processing, Properties, and Applications of Closed-Cell Aluminum Foams: A Review.

Closed-cell aluminum foams have many excellent properties, such as low density, high specific strength, great energy absorption, good sound absorption, electromagnetic shielding, heat and flame insulation, etc. As a new kind of material, closed-cell aluminum foams have been used in lightweight structures, traffic collision protections, sound absorption walls, building decorations, and many other places. In this paper, the recent progress of closed-cell aluminum foams, on fabrication techniques, including the melt foaming method, gas injection foaming method, and powder metallurgy foaming method, and on processing techniques, including powder metallurgy foaming process, two-step foaming process, cast foaming process, gas injection foaming process, mold pressing process, and integral foaming process, are summarized. Properties and applications of closed-cell aluminum foams are discussed based on the mechanical properties and physical properties separately. Special focuses are made on the newly developed cast-forming process for complex 3D parts and the improvement of mechanical properties by the development of small pore size foam fabrication and modification of cell wall microstructures.

Micromachining techniques for manufacturing high aspect ratio microelectrodes: A review

The advancement in micromanufacturing techniques has increased due to the demand for microtools used in biomedical engineering. The development of tailored micro-sized components has advanced significantly as manufacturing accuracy has improved. Although the machining of smaller dimensions is not new, difficulties arise when features are reduced to tens or hundreds of microns in size. Micro-machining technology is progressing towards the production of complex 3D parts. The creation of very precise equipment is essential to achieving productivity goals in terms of effectiveness, adaptability, robustness, and accuracy. Since even a minor modification can have a significant impact on machining performance, precise control over the machining variables is essential. This review paper describes the literature of subtractive micro manufacturing processes (traditional and advanced). In addition to subtractive processes, an overview of various micro machining techniques such as additive, mass containing and joining processes has been studied. In this paper, various micromachining techniques for fabricating high aspect ratio microelectrodes are studied and evaluated to find the suitable machining process to fabricate micro electrodes. The growing demand in the micro sector has attracted attention to the fabrication of high-aspect micro tools with diameters below 100 μm and high accuracy and precision.

Through the Forming Process of Femtosecond-Laser Nanotextured Sheets for Production of Complex 3D Parts

The use of ultra-short pulse lasers in the kW range, combined with an appropriate beam engineering approach, enables the achievement of high-throughput production of laser-functionalised surfaces. However, the manufacturing of complex parts still faces various challenges, such as difficulties in accessing regions with high aspect ratio shapes or intricate profiles, which often leads to the necessity of adapting the laser processing workstation to specific geometries. The forming process is a well-established technique for producing parts of any shape from metallic foils by imposing specific constraints. In this study, we aimed to assess the feasibility of producing laser-functionalised 3D complex products by the forming of laser-treated flat thin metallic sheets. Two-hundred micrometre-thick stainless-steel foils were textured with laser-induced periodic surface structures (LIPSS) through a roll-to-roll pilot line. First, we optimized the morphology of LIPSS. Subsequently, we conducted three types of mechanical tests on both laser-treated and untreated foils: standard tensile tests, fatigue tests, and cruciform specimen tests. We measured and compared parameters such as ultimate tensile strength, breaking strength, maximum elongation, and area reduction between specimens with and without LIPSS, all obtained from the same foil. Additionally, we utilized scanning electron microscopy (SEM) to compare the LIPSS morphology of laser-treated samples before and after mechanical tests.

A review of the performance of polymer parts printed on fused deposition modelling under cyclic loading

Fused deposition modelling (FDM) is one of the most promising and widely used additive manufacturing (AM) technologies. FDM is commonly used to fabricate simple to complex 3D parts from polymeric materials. Different 3D-printed polymeric components manufactured using FDM technology exhibit various mechanical and load-bearing properties. They are utilized in various industries, particularly the medical industry, for load-bearing applications in bio-implants. Therefore, it is crucial to understand the mechanical characteristics, especially the fatigue behaviour, of these 3D-printed parts under cyclic loadings. This paper focuses on the dynamic behaviour of 3D-printed polymeric parts produced through the FDM process and under different loading modes. First, the FDM mechanism, the various polymeric materials used in FDM, and the effective FDM parameters are briefly introduced. Then, the paper comprehensively covers one of the most important mechanical characteristics of 3D-printed parts for load-bearing applications: their fatigue life under different printing conditions and cyclic loadings. The most influential factors on the fatigue behaviour of polymers include the type of polymeric material, surrounding environmental conditions, cyclic loading conditions, the type of testing specimen, and the FDM printing parameters (such as raster angle, infill density, nozzle diameter, and nozzle temperature). In addition to the anisotropic behaviour reported by various studies on 3D-printed parts using FDM, it has been concluded that the layered structure (with a large number of interfaces between the raster) and the presence of microholes are two factors that weaken the fatigue strength of 3D-printed structures compared to other fabrication processes. These conditions can be exacerbated by choosing inappropriate printing parameters, and often, the failure mechanism in 3D-printed parts fabricated with FDM is delamination.

Numerical and experimental analysis of the localized electrodeposition (LED) based micro additive manufacturing process

The localized electrodeposition process (LED) is a non-thermal additive manufacturing process that uses the combination of the electrochemical deposition principle and additive manufacturing. It is capable of producing complex 3D parts directly from the CAD model. The deposition is localized by the use of a micro tool of a diameter much smaller than the substrate. This process can produce sub-micrometer features size components using materials including metal, alloys, and polymers. In this study numerical modeling was performed to study the effect of applied voltage, and interelectrode gap on the deposition rate for the nickel-based electrolyte. The microelectrochemical additive manufacturing process was analyzed through a numerical study using COMSOL® Multiphysics software. The simulation incorporated boundary conditions aligned with the process parameters for localized electrodeposition. Notably, the simulation results demonstrated strong agreement with the experimental output obtained from the developed LED setup.

Experimental investigation of nanosecond laser Machining of 3D printed carbon fiber reinforced polymer (CFRP) composite

Carbon fiber reinforced polymer (CFRP) composites are widely used in automotive and aerospace applications due to their high specific strengths, high fatigue and creep resistance, and excellent corrosion resistance. Additive manufacturing (AM) or 3D printing has opened new ways of manufacturing complex 3D parts using CFRP composites. As a result, researchers have gained interest in the machining or post-processing of 3D-printed CFRP composites. This study aims to investigate the feasibility of using a nanosecond laser for machining single craters or blind holes and slots on 3D printed CFRP samples and understand the effects of important process parameters on feature dimensions, (i.e., crater diameter, slot width, crater/hole depth, and slot depth), heat affected zone (HAZ), and surface quality of the machined features. A 1064 nm wavelength laser system with a focal length of 160 mm was used, whereas the number of pulses, laser energy level, and back-and-forth laser passes are varied. The heat-affected zone is found to be influenced by the laser energy level as compared to the number of pulses. It is found that for the same number of pulses, there is a clear sign of an increase in HAZ with the increase in laser energy level. With the increase in the number of pulses, the hole or slot edge becomes more defined and clearer, whereas the HAZ is mostly determined by the energy level. There is an accumulation of molten or removed materials at the edge of holes or slots causing jagged edges of machined features, which gradually diminishes when the edge becomes smoother for a higher number of pulses, or accumulated materials evaporate away at the higher setting of energy level. Finally, it is found that the nanosecond laser system is capable of machining quality holes and slots on the 3D-printed CFRP composite. To obtain features with well-defined profiles and minimal heat-affected zone, an understanding of the effects of laser process parameters is important.

Surface Functionalization of 4D Printed Substrates Using Polymeric and Metallic Wrinkles.

Wrinkle topographies have been studied as simple, versatile, and in some cases biomimetic surface functionalization strategies. To fabricate surface wrinkles, one material phenomenon employed is the mechanical-instability-driven wrinkling of thin films, which occurs when a deforming substrate produces sufficient compressive strain to buckle a surface thin film. Although thin-film wrinkling has been studied on shape-changing functional materials, including shape-memory polymers (SMPs), work to date has been primarily limited to simple geometries, such as flat, uniaxially-contracting substrates. Thus, there is a need for a strategy that would allow deformation of complex substrates or 3D parts to generate wrinkles on surfaces throughout that complex substrate or part. Here, 4D printing of SMPs is combined with polymeric and metallic thin films to develop and study an approach for fiber-level topographic functionalization suitable for use in printing of arbitrarily complex shape-changing substrates or parts. The effect of nozzle temperature, substrate architecture, and film thickness on wrinkles has been characterized, as well as wrinkle topography on nuclear alignment using scanning electron microscopy, atomic force microscopy, and fluorescent imaging. As nozzle temperature increased, wrinkle wavelength increased while strain trapping and nuclear alignment decreased. Moreover, with increasing film thickness, the wavelength increased as well.

Effects of powder properties on the 3D printing of BaTiO3 ceramic resins by stereolithography

Stereolithography is a layer-by-layer building fabrication technique enabling production of advanced ceramic 3D shapes that are not achievable by other methods. Critical parameters of stereolithography are associated with the preparation of a ceramic resin exhibiting suitable rheological and optical properties, as well as tunable curing property to achieve the desired level of resolution of complex 3D parts. However, tailoring the cure depth for each layer is challenging for functional ceramics due to their high refractive index giving increased light scattering. Here, the stereolithography 3D printing of BaTiO3 ceramic resins is investigated by employing a desktop 3D printer (λ = 405 nm) and a commercial base resin. The effects of two BaTiO3 powders with different size distributions (one micro-sized powder with grains in the range 1–20 µm, and one agglomerated nano-sized powder in the range 60–100 nm), on the viscosity and curing characteristics of the ceramic resins were investigated. It is shown that the nano-sized powder resulted in increased viscosity, increased scattering, and reduced cure depth compared to the micro-sized BaTiO3 ceramic resin. In general, the cure depth decreased with increasing ceramic loading. Successful prints were obtained for an overcuring of at least 40% between layers to assure good adherence between the layers. The printing properties of the ceramic resins from both powders were suitable for printing green parts with 50 µm layer thickness.

Using 3D Density-Gradient Vectors in Evolutionary Topology Optimization to Find the Build Direction for Additive Manufacturing

Given its layer-based nature, additive manufacturing is known as a family of highly capable processes for fabricating complex 3D geometries designed by means of evolutionary topology optimization. However, the required support structures for the overhanging features of these complex geometries can be concerningly wasteful. This article presents an approach for studying the manufacturability of the topology-optimized complex 3D parts required for additive manufacturing and finding the optimum corresponding build direction for the fabrication process. The developed methodology uses the density gradient of the design matrix created during the evolutionary topology optimization of the 3D domains to determine the optimal build orientation for additive manufacturing with the objective of minimizing the need for support structures. Highly satisfactory results are obtained by implementing the developed methodology in analytical and experimental studies, which demonstrate potential additive manufacturing mass savings of 170% of the structure’s weight. The developed methodology can be readily used in a variety of evolutionary topology optimization algorithms to design complex 3D geometries for additive manufacturing technologies with a minimized level of waste due to reducing the need for support structures.

Embedded 3D Printing of Thermally-Cured Thermoset Elastomers and the Interdependence of Rheology and Machine Pathing.

Thermoset elastomers are widely used high-performance materials due to their thermal stability, chemical resistance, and mechanical properties. However, established casting and molding techniques limit the overall 3D complexity of parts that can be fabricated. Advanced manufacturing methods such as 3D printing have improved design flexibility and reduced development time but have proved challenging using thermally-cured thermosets due to their viscosity, slow gelation kinetics and high surface tension. To address this, freeform reversible embedding (FRE) 3D printing extrudes thermosets such as polydimethylsiloxane (PDMS) elastomer within a carbomer support bath, but due to the liquid-like state of the prepolymer during extrusion has been limited to hollow structures. Here, we have significantly improved FRE printing through rheological modification of PDMS with a thixotropic additive (1.0-10.0 wt%) that imparts a yield stress (30-120 Pa) to help control filament morphology. Further, to minimize the interaction of the nozzle with previously printed PDMS we implemented print process controls consisting of region-specific slicing, filament retraction, and non-print travel moves outside of the print. The combined result is the FRE printing of PDMS in complex 3D parts with high fidelity, establishing a 3D printing methodology that can be used broadly with thermally-cured thermoset elastomers and related polymers.

A Convolutional Neural Network (CNN) classification to identify the presence of pores in powder bed fusion images

This study aims to detect seeded porosity during metal additive manufacturing by employing convolutional neural networks (CNN). The study demonstrates the application of machine learning (ML) in in-process monitoring. Laser powder bed fusion (LPBF) is a selective laser melting technique used to build complex 3D parts. The current monitoring system in LPBF is inadequate to produce safety-critical parts due to the lack of automated processing of collected data. To assess the efficacy of applying ML to defect detection in LPBF by in-process images, a range of synthetic defects have been designed into cylindrical artefacts to mimic porosity occurring in different locations, shapes, and sizes. Empirical analysis has revealed the importance of accurate labelling strategies required for data-driven solutions. We formulated two labelling strategies based on the computer-aided design (CAD) file and X-ray computed tomography (XCT) scan data. A novel CNN was trained from scratch and optimised by selecting the best values of an extensive range of hyper-parameters by employing a Hyperband tuner. The model’s accuracy was 90% when trained using CAD-assisted labelling and 97% when using XCT-assisted labelling. The model successfully spotted pores as small as 0.2mm. Experiments revealed that balancing the data set improved the model’s precision from 89% to 97% and recall from 85% to 97% compared to training on an imbalanced data set. We firmly believe that the proposed model would significantly reduce post-processing costs and provide a better base model network for transfer learning of future ML models aimed at LPBF micro-defects detection.

Mo-Se-N dry lubricant coatings as a universal solution for protecting surfaces of complex 3D parts

One of the most crucial issues encountered in the implementation of sputtered solid lubricant coatings at an industrial scale is the non-uniformity of properties achieved on complex 3D components. This is due to the fact that compositional variations are unavoidable on these complex parts. This limitation can only be overcome if a system is developed which can present consistent sliding properties despite of chemical composition variations. To address this crucial issue, in this work, for the first time DC sputtered Mo-Se-N coatings are explored. The coatings were deposited in a semi-industrial setup with different chemical compositions. All coatings were rather compact, X-ray amorphous and had maximum hardness of ∼5 GPa. During the tribological testing in ambient air at room temperature, all coatings displayed consistent and similar friction coefficient and specific wear rates, showing their high potential to be used for the depositions on 3D parts.

Feasibility of manufacturing of Al2O3–Mo HTCC by hybrid additive process

Additive manufacturing processes make it possible to produce increasingly complex 3D parts. In addition, these numerical processes can be usefully used to manufacture ceramic/metal parts of high dimensional resolution with thermal, electrical and electronic properties of interest for applications in the field of power electronics.In this context, a hybrid additive machine was developed to manufacture ceramic/metal parts. This machine consists in the combination of two additive manufacturing processes: stereolithography and robocasting.Using this hybrid process, the feasibility of HTCC components has been demonstrated by building dielectric alumina by stereolithography and molybdenum conductive network by robocasting. Molybdenum-based metallic formulation adapted to the process and allowing to obtain a high conductive metallic network has been developed. The co-debinding and co-sintering cycles have been optimized to minimize the content of residual carbon and to prevent the oxidation of molybdenum. The alumina/molybdenum interface has also been observed to conclude about a possible delamination between these two materials with different thermal expansion coefficients (CTE). Sintered HTCC parts have been characterized in the domain of hyperfrequency. The frequency responses deviate from the simulation due to a lack of dimensional accuracy of the metallic network.

Toxicity evaluation of particles formed during 3D-printing: Cytotoxic, genotoxic, and inflammatory response in lung and macrophage models

Additive manufacturing (AM) or “3D-printing” is a ground-breaking technology that enables the production of complex 3D parts. Its rapid growth calls for immediate toxicological investigations of possible human exposures in order to estimate occupational health risks. Several laser-based powder bed fusion AM techniques are available of which many use metal powder in the micrometer range as feedstock. Large energy input from the laser on metal powders generates several by-products, like spatter and condensate particles. Due to often altered physicochemical properties and composition, spatter and condensate particles can result in different toxicological responses compared to the original powder particles. The toxicity of such particles has, however, not yet been investigated. The aim of the present study was to investigate the toxicity of condensate/spatter particles formed and collected upon selective laser melting (SLM) printing of metal alloy powders, including a nickel-chromium-based superalloy (IN939), a nickel-based alloy (Hastelloy X, HX), a high-strength maraging steel (18Ni300), a stainless steel (316L), and a titanium alloy (Ti6Al4V). Toxicological endpoints investigated included cytotoxicity, generation of reactive oxygen species (ROS), genotoxicity (comet and micronucleus formation), and inflammatory response (cytokine/chemokine profiling) following exposure of human bronchial epithelial cells (HBEC) or monocytes/macrophages (THP-1). The results showed no or minor cytotoxicity in the doses tested (10−100 μg/mL). Furthermore, no ROS generation or formation of micronucleus was observed in the HBEC cells. However, an increase in DNA strand breaks (detected by comet assay) was noted in cells exposed to HX, IN939, and Ti6Al4V, whereas no evident release of pro-inflammatory cytokine was observed from macrophages. Particle and surface characterization showed agglomeration in solution and different surface oxide compositions compared to the nominal bulk content. The extent of released nickel was small and related to the nickel content of the surface oxides, which was largely different from the bulk content. This may explain the limited toxicity found despite the high Ni bulk content of several powders. Taken together, this study suggests relatively low acute toxicity of condensates/spatter particles formed during SLM-printing using IN939, HX, 18Ni300, 316L, and Ti6Al4V as original metal powders.

Effects of auxiliary heat on the interlayer bonds and mechanical performance of polylactide manufactured through fused deposition modeling

The inherent interfacial bonding formation of layers determines the quality of complex 3D parts fabricated using fused deposition modeling (FDM). The inferior and anisotropic mechanical properties of FDM parts prevent their industrial application. This research is aimed at enhancing the mechanical properties and reducing the mechanical anisotropy of FDM parts through an innovative auxiliary heating treatment. Polylactide (PLA), which is a distinct semicrystalline polymer commonly used in 3D printing, was selected to examine the enhancement of mechanical properties by implementing auxiliary heating treatment. When the auxiliary heating treatment is applied, the tensile strength of the FDM-printed PLA part increases from 38.4 MPa to 63.6 MPa, and the degree of mechanical anisotropy decreases from 0.51 to 0.22. The auxiliary heating treatment yields superior mechanical properties compared to those attained through post-thermal annealing. Auxiliary heating represents a kind of “in-situ” annealing strategy during FDM printing. Moreover, the auxiliary heating temperature is similar to the cold crystallization temperature (Tcc) of PLA and is the optimal processing condition to obtain superior mechanical properties. As indicated by the SEM and DSC methods, the interfacial bonding of adjacent strands and crystallinity considerably influence the mechanical properties of FDM-printed PLA parts. Therefore, the auxiliary heating approach has the potential to be applied in the fabrication of large FDM parts.

Investigations on the Effect of Layers' Thickness and Orientations in the Machining of Additively Manufactured Stainless Steel 316L.

Laser-powder bed fusion (L-PBF) process is a family of modern technologies, in which functional, complex (3D) parts are formed by selectively melting the metallic powders layer-by-layer based on fusion. The machining of L-PBF parts for improving their quality is a difficult task. This is because different component orientations (L-PBF-layer orientations) produce different quality of machined surface even though the same cutting parameters are applied. In this paper, stainless steel grade SS 316L parts from L-PBF were subjected to the finishing (milling) process to study the effect of part orientations. Furthermore, an attempt is made to suppress the part orientation effect by changing the layer thickness (LT) of the parts during the L-PBF process. L-PBF parts were fabricated with four different layer thicknesses of 30, 60, 80 and 100 μm to see the effect of the LT on the finish milling process. The results showed that the layer thickness of 60 μm has significantly suppressed the part orientation effect as compared to the other three-layer thicknesses of 30, 80 and 100 μm. The milling results showed that the three-layer thickness including 30, 80 and 100 μm presented up to a 34% difference in surface roughness among different part orientations while using the same milling parameters. In contrast, the layer thickness of 60 μm showed uniform surface roughness for the three-part orientations having a variation of 5–17%. Similarly, the three-layer thicknesses 30, 80 and 100 μm showed up to a 25%, 34% and 56% difference of axial force (Fa), feed force (Ff) and radial force (Fr), respectively. On the other hand, the part produced with layer thickness 60 μm showed up to 11%, 25% and 28% difference in cutting force components Fa, Ff and Fr, respectively. The three-layer thicknesses 30, 80 and 100 μm in micro-hardness were found to vary by up to 14.7% for the three-part orientation. Negligible micro-hardness differences of 1.7% were revealed by the parts with LT 60 μm across different part orientations as compared to 6.5–14% variations for the parts with layer thickness of 30, 80 and 100 μm. Moreover, the parts with LT 60 μm showed uniform and superior surface morphology and reduced edge chipping across all the part orientations. This study revealed that the effect of part orientation during milling becomes minimum and improved machined surface integrity is achieved if the L-PBF parts are fabricated with a layer thickness of 60 μm.