Computer Numerical Control Milling Research Articles

Precision-milled simulated curved root canals in bovine dentine for the assessment of chemo-mechanical root canal preparation.

The aim was to develop a standardized curved root canal model in bovine dentine and to assess whether that natural substrate would behave differently from the resin in standard plastic training blocks when prepared chemo-mechanically. The impact of substrate microhardness on simulated canal transportation was considered. High-precision computer numerical control (CNC) milling was used to recreate a simulated root canal from a resin training block (Endo Training Bloc J-Shape, size 15) in longitudinally sectioned, dis- and re-assembled bovine incisor roots. Optical overlays obtained from 10 resin blocks were used to identify an average canal and program the CNC milling apparatus accordingly. Resin and dentine microhardness were measured. Simulated root canals in resin training blocks and their bovine counterparts were then instrumented at 37°C using Reciproc R25 instruments (VDW) with water or 17% EDTA (n = 10). Open-access image processing software was used to superimpose and analyse pre- and postoperative images obtained with a digital microscope. Centering ratios were averaged to indicate canal transportation. The effects of substrate and irrigant on canal transportation were assessed by two-way anova. Superimposed images showed that resin blocks under investigation varied considerably in terms of simulated canal length and curvature, whilst the milled canals were highly similar. The microhardness of dentine was more than three times higher than that of the resin. Conversely, canal transportation was considerably greater in dentine compared to resin, and in dentine had a tendency to be increased by EDTA. There was a strong effect of substrate on canal transportation (p < .001), no overall effect of irrigant, and a marginally significant interaction between irrigant and substrate (p = .077). CNC milling allows to create standardized simulated curved root canals in bovine dentine. These models may be useful to test and compare materials and concepts of chemo-mechanical root canal instrumentation. Microhardness is a bulk feature that does not predict the response to chemo-mechanical instrumentation of a composite material such as dentine.

An ensemble neural network for optimising a CNC milling process

Computer numerical control (CNC) milling is a common method for the efficient mass production of products. Process efficiency and product quality have a strong dependency on the cutting process conditions. Furthermore, optimising a process for material removal rate (MRR) and surface roughness (SR), which are measures of process efficiency and product quality, respectively, is a complex optimisation task due to their contrasting relationships with process parameters. In this work, CNC end milling is performed on aluminium 6061 to investigate the influence of key process input variables (feed per tooth, cutting speed, and depth of cut) on the machined part’s SR. Firstly, a full factorial parametric study is conducted and analysed using Analysis of Variance (ANOVA) before an Ensemble Neural Network (ENN) is trained on the experimental data. To capture the complex nonlinear relationships accurately, each base model of the ENN is a combined genetic algorithm-artificial neural network, whose hyperparameters are optimised using a Bayesian optimisation framework. Once trained, the ENN predictive model is exploited to identify optimal input parameter permutations to achieve a predefined SR value while maximising MRR. Analysing the experimental data demonstrates that the SR performance envelope is nonlinear with respect to the input variables. Furthermore, the ANOVA results indicate that feed per tooth is the dominant input parameter with a contribution of 40.2% and that there are strong interactions between the input parameters investigated. The ENN performance was subsequently validated through a further set of experiments producing a mean absolute percentage error in predicted SR of just 2.56%.

Exergy Loss Assessment Method for CNC Milling System Considering the Energy Consumption of the Operator

Modeling and assessing the sustainability of machining systems has been considered to be a crucial approach to improving the environmental performance of machining processes. As the most common machining system, the computer numerical control (CNC) milling system is a typical man–machine cooperative system where the activities of the machine tool and operator generate material and energy consumption. However, the energy consumption of the operator in the CNC milling system has often been ignored in most existing research. Therefore, existing methods fail to provide a comprehensive understanding of the sustainability of the CNC milling system. To fill this gap, an exergy loss assessment method is proposed to investigate the sustainability of the CNC milling system, where the energy consumption of the operator, the energy consumption of the machine tool, and material consumption are taken into consideration. The key performance indexes of the energy consumption of the operator, the energy consumption of the machine tool, the exergy loss, and the specific exergy loss (SEL) are analyzed and modeled. To demonstrate the feasibility of the proposed method, a case study was carried out on a three-axis machining center (XH714D), in which the energy consumption of the operator, the energy consumption of the machine tool, the exergy loss of energy consumption, the exergy loss of chips, the exergy loss of compressed air, the exergy loss of cutting tool wear, the exergy loss of cooling liquid dissipation, and the SEL were found to be 169,750 J, 758,211 J, 603,131 J, 2,031,404 J, 22,023 J, 301,868 J, 2673 J, and 88.04 J/mm3, respectively. The proposed method is effective to assess the sustainability of the CNC milling system, and the established exergy loss models build a good basis for exergy efficiency optimization.

An efficient analytical model for the swept volume generation of a flat-end mill in 5-axis CNC milling

5-axis CNC (Computer Numerical Control) milling is widely used to create complex part geometries in the industrial area. The cutting tool creates the swept volume as it moves along the defined path. The swept volume is subtracted from the initial stock for the machining simulation. Although a swept volume consists of three parts such as ingress, egress, and swept envelope, the number of faces of the swept volume is higher than three. In this work, parametric equations of the faces of the swept volume were obtained for a flat-end mill in four steps. The model is based on the decomposition of the tool into circles along the tool orientation vector since a flat-end mill can be modeled as a cylinder. The fundamental principle is that each circle is tangent to the swept envelope of the cylinder. Locations of the grazing points with respect to a local coordinate system were determined by applying the Envelope Theory to the parameterized circle of the cylinder. Then, each face of the swept volume was represented based on the equation of the parameterized circle. The model was verified by using an alternative analytical model. As a result, boundaries of the swept volume were represented fully analytically for a flat-end mill in 5-axis CNC milling in an efficient way.

Evaluation of surface roughness of differently manufactured denture base materials

The popularity of computer-aided design and computer-aided manufacturing (CAD-CAM) dentures has led to the introduction of new denture materials and resins. However, studies on the surface characteristics of these materials and how they compare to dentures fabricated by more traditional methods are lacking. The purpose of this cross-sectional study was to determine whether the surface roughness (Ra) of denture base materials differed based on manufacturing technique. Disks of Ø10×2-mm (n=10) were fabricated using 6 different manufacturing techniques, including compression molding (Lucitone 199), injection molding (Ivocap High Impact), Computer Numerical Control (CNC) milling (Ivotion Base), and additive manufacturing on the Carbon M2 (Lucitone Digital Print), the SprintRay Pro55 S (Dentca Denture Base II), and the Envision One (Flexcera Base) systems. An automatic, noncontact laser confocal microscope (VK-X1000 Series; KEYENCE) was used to analyze the Ra surface roughness of each specimen at ×5 magnification. The images were imported into a multifile analyzer, horizontal and vertical roughness profiles were inserted into each scan, and Ra values were calculated and averaged by following the International Organization for Standardization (ISO) 4287 standard. A 1-way analysis of variance (ANOVA) was performed to compare the effect of manufacturing technique on surface roughness, followed by the Tukey multiple comparisons test (α=.05). The additively manufactured Dentca Denture Base II (AM-DB) exhibited a statistically significantly higher Ra when compared with the other test groups (P<.001). The additively manufactured Flexcera Base (AM-FB) showed a higher Ra mean value when compared with injection molding (IM) (P=.036). No statistically significant difference in surface roughness was found among the other tested materials representing the different processing methods (P>.05). The manufacturing method influences the Ra of denture base materials with varying results. The injection molding method resulted in the smoothest surface compared with additively manufactured and CNC-milled denture base materials.

Compact Wideband Groove Gap Waveguide Bandpass Filters Manufactured with 3D Printing and CNC Milling Techniques.

This paper presents for the first time a compact wideband bandpass filter in groove gap waveguide (GGW) technology. The structure is obtained by including metallic pins along the central part of the GGW bottom plate according to an n-order Chebyshev stepped impedance synthesis method. The bandpass response is achieved by combining the high-pass characteristic of the GGW and the low-pass behavior of the metallic pins, which act as impedance inverters. This simple structure together with the rigorous design technique allows for a reduction in the manufacturing complexity for the realization of high-performance filters. These capabilities are verified by designing a fifth-order GGW Chebyshev bandpass filter with a bandwidth BW = 3.7 GHz and return loss RL = 20 dB in the frequency range of the WR-75 standard, and by implementing it using computer numerical control (CNC) machining and three-dimensional (3D) printing techniques. Three prototypes have been manufactured: one using a computer numerical control (CNC) milling machine and two others by means of a stereolithography-based 3D printer and a photopolymer resin. One of the two resin-based prototypes has been metallized from a silver vacuum thermal evaporation deposition technique, while for the other a spray coating system has been used. The three prototypes have shown a good agreement between the measured and simulated S-parameters, with insertion losses better than IL = 1.2 dB. Reduced size and high-performance frequency responses with respect to other GGW bandpass filters were obtained. These wideband GGW filter prototypes could have a great potential for future emerging satellite communications systems.

Deep representation learning and reinforcement learning for workpiece setup optimization in CNC milling

Computer Numerical Control (CNC) milling is a commonly used manufacturing process with a high level of automation. Nevertheless, setting up a new CNC milling process involves multiple development steps relying heavily on human expertise. In this work, we focus on positioning and orientation of the workpiece (WP) in the working space of a CNC milling machine and propose a deep learning approach to speed up this process significantly. The selection of the WP’s setup depends on the chosen milling technological process, the geometry of the WP, and the capabilities of the considered CNC machining. It directly impacts the milling quality, machine wear, and overall energy consumption. Our approach relies on representation learning of the milling technological process with the subsequent use of reinforcement learning (RL) for the WP positioning and orientation. Solutions proposed by the RL agent are used as a warm start for simple hill-climbing heuristics, which boosts overall performance while keeping the overall number of search iterations low. The novelty of the developed approach is the ability to conduct the WP setup optimization covering both WP positioning and orientation while ensuring the axis collision avoidance, minimization of the axis traveled distances and improving the dynamic characteristics of the milling process with no input from human experts. Experiments show the potential of the proposed learning-based approach to generate almost comparably good WP setups order of magnitude faster than common metaheuristics, such as genetic algorithms (GA) and Particle Swarm Optimisation (PSA).

Monitoring and classification of polymeric surface features for enabling the adoption of polypropylene powder bed fusion as a standard tool for bioprocessing equipment production

Polypropylene (PP) powder bed fusion (PBF) with subsequent mechanical postprocessing can enable the development of more efficient and effective surfaces for bioprocessing equipment. However, there is still a lack of knowledge regarding the most relevant surface differences when compared to standardized surfaces. Herein, we present a new systematic methodology, including the evaluation of relevant roughness parameters and surface wettability, which has been implemented to assess the potential of AM to produce biopharmaceutical components. Surfaces of PP components produced by PBF and mechanically postprocessed by tumble surface finishing at 5, 10 and 15 h were compared to reference surfaces produced by computer numerical control (CNC) milling manufacturing. Thirteen roughness parameters were found to be relevant, of which the arithmetic mean peak curvature (Spc) and the density of peaks (Spd) were the most significant. The results demonstrate that the reference surfaces had Spc and Spd values of 1029 ± 36 mm−1 and 67739 ± 5440 mm−2, respectively, and moderate wettability with advancing (ACA) and receding (RCA) contact angles of 89 ± 3° and 68 ± 2°, respectively. The as-printed PBF surfaces were hydrophobic, with ACA of 119 ± 2° and RCA of 107 ± 4°, and with Spc and Spd values of 1089 ± 110 mm−1 and 30078 ± 4325 mm−2, respectively. PBF surfaces switched to a hydrophilic surface of 67 ± 3° and 44 ± 4° when the tumble surface finishing time was increased to 15 h. By taking advantage of this knowledge, we could produce surfaces using PBF and 5 h of mechanical postprocessing, which mimicked surface wetting and had Spc of 1100 ± 68 mm−1 and Spd of 55702 ± 9477 mm−2, similar to that of the CNC milling manufacturing. The developed comparative method and the results are important to better understand AM surfaces and can be used to transfer manufacturing from subtractive to additive technologies.

Roughness Test of Aluminum A5052 before and after Forming by SPIF Process

Single point incremental forming process, which is also known as SPIF, that forms from one direction. SPIF process was used for milling an aluminum metallic sheet. In this paper, an aluminum (A5052) sheet was formed in a conical shape by the SPIF process. The A5052 sheet was deformed by the computer numerical control (CNC) technology in the T60 series milling machine. The conical shape was deformed by the spiral toolpath in the T60 series milling machine. At the surface of the A5052, lubricant grease was continuously applied manually for reducing the friction generated due to milling. Also, for decreasing the tool rotational force friction on the A5052 sheet there was the use of lubricant. Moreover, 0.1mm step-down is used for the tool path because it takes more time for forming a metallic sheet, however, it deformed the sheet smoothly. The 0.5mm step-down g-code was extracted from fusion 360. Then the metallic sheet A5052 surface was compared before and after deformation. For testing a metallic sheet A5052 the formability parameter was analyzed in the experiment part. The experiment was performed to find the optimal smooth surface from the CNC milling machine. The initial roughness value and the microscopic image were presented in the investigational part. Likewise, the comparison of points for the highest and lowest rough point was further discussed and compared throughout the experiment.

Increasing the Performance of Computer Numerical Control Machine via the Dhouib-Matrix-4 Metaheuristic

The Computer Numerical Control (CNC) machine represents a turning point in today's production which has high requirements for product accuracy. The CNC machine enables a high flexibility in work and time saving and also reduces the time required for product accuracy control. Moreover, the CNC machine are used for several activities, most often for turning, drilling and milling operations. Usually, the productivity of any CNC machine can be increased thanks to the minimization of the non-productive of tool movement. In this paper, the results of a new metaheuristic named Dhouib-Matrix-4 (DM4) with an application on the NP-hard problem based on the Travelling Salesman Problem are presented. DM4 is used for increasing the performance of the CNC Machine by optimizing a tool path length in the drilling process performed on the CNC milling machine. The proposed algorithm (DM4) achieves a solution closed to the optimum, compared with the results obtained with the Ant Colony Optimization algorithm and the results found with the manual programming in G code by using a control unit for the selected CNC milling machine.

170–260-GHz Ultrawideband and High Isolation Orthomode Transducer Based on Symmetric Reverse Coupling Structure

In this article, we propose a novel ultrawideband orthomode transducer (OMT) with high isolation. This novel OMT is designed based on a symmetric reverse coupling structure, which employs two forms of double ridges to replace the pillars or septums that are difficult to process. In this way, the OMT achieves simpler double symmetry structure with higher tolerance capability and lower processing difficulty. In addition, the impedance-matching characteristics within the waveguide are optimized by the symmetrical double-ridged structure, allowing wider bandwidth and higher isolation to be obtained than in conventional structures. To confirm the theoretical results, a WR-4.3 full-band OMT was processed by computer numerical control (CNC) milling technology with 10- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $</tex-math> </inline-formula> m precision. Measurement results show that in the 170–260 GHz range, the average return loss (RL) is 24 dB, the average insertion loss (IL) is 0.6 dB, and the average isolation is 54 dB. The measured results are strongly in agreement with the simulation results.

Fused Filament Fabrication and Computer Numerical Control Milling in Cultural Heritage Conservation.

This paper reports a comparison between the advantages and disadvantages of fused filament fabrication (FFF) and computer numerical control (CNC) milling, when applied to a specific case of conservation of cultural heritage: the reproduction of four missing columns of a 17th-century tabernacle. To make the replica prototypes, European pine wood (the original material) was used for CNC milling, while polyethylene terephthalate glycol (PETG) was used for FFF printing. Neat materials were chemically and structurally characterized (FTIR, XRD, DSC, contact angle measurement, colorimetry, and bending tests) before and after artificial aging, in order to study their durability. The comparison showed that although both materials are subject to a decrease in crystallinity (an increase in amorphous bands in XRD diffractograms) and mechanical performance with aging, these characteristics are less evident in PETG (E = 1.13 ± 0.01 GPa and σ = 60.20 ± 2.11 MPa after aging), which retains water repellent (ca = 95.96 ± 5.56°) and colorimetric (∆E = 2.6) properties. Furthermore, the increase in flexural strain (%) in pine wood, from 3.71 ± 0.03% to 4.11 ± 0.02%, makes it not suitable for purpose. Both techniques were then used to produce the same column, showing that for this specific application CNC milling is quicker than FFF, but, at the same time, it is also much more expensive and produces a huge amount of waste material compared to FFF printing. Based on these results, it was assessed that FFF is more suitable for the replication of the specific column. For this reason, only the 3D-printed PETG column was used for the subsequent conservative restoration.

Manufacturing Guidelines for W-Band Full-Metal Waveguide Devices: Selecting the most appropriate technology

This article analyzes some of the key aspects of manufacturing techniques for passive components and antennas in the millimeter band, with emphasis on the W band. Even experienced microwave designers might face great technological challenges when upscaling their designs to higher-frequency bands. Thus, several manufacturing technologies are widely analyzed in this work by designing, manufacturing, and measuring different components in the W band. Subtractive manufacturing techniques, such as computer numerical control (CNC) milling and electrical discharge machining (EDM), as well as additive manufacturing techniques, including stereolithography (SLA), direct metal laser sintering (DMLS), and diffusion bonding (DB) are explored. The advantages and disadvantages of these technologies are evaluated using features such as manufacturing tolerances, accuracy, surface roughness, and cost. The purpose is to offer some guidelines for the selection of the most appropriate manufacturing technology in the W band, bearing in mind both the performance of the different manufacturing methods and the particular circuital topologies of the component under development.

Design, construction, and performance of a próton exchange membrane water electrolyzer (PEM-WE)

This work presents the design and construction of a proton exchange membrane water electrolyzer (PEM-WE) for H2 production. The evaluation of the flow regimen in the flow channels was performed by computational fluid dynamic anlysis (CFD). The cell components were machined by computer numerical control (CNC) milling. The electrode membrane assembly (MEA) manufacturing consisted of a Nafion® 117 membrane and electrodes with an active area of 100 cm2. Electrocatalysts were deposited using the electrospray technique with a metal loading of 1 mg of Pt cm−2 in the cathode zone and 2 mg IrO∙cm−2 in the anode region. The different components were assembled to the six cell stack PEM-WE, which was held with a bolt torque of 1.7 N∙m. The PEM-WE stack was characterized in a potential range from to 11.8–15 V at a temperature interval ranging from 30 °C to 70 °C. Deionized water was supplied at 300 mL∙min−1. The best performance was registered when operating at 15 V and 70 °C, for an efficiency of 59.65%. The hydrogen production amount was 42 NL∙ h−1, and theamount of power consumed was 132 W∙h.

Life cycle assessment of metal products: A comparison between wire arc additive manufacturing and CNC milling

The industrial progress made throughout these years has led to great results in terms of producing fast and with good quality. However, the impacts related to that production, whether these are environmental, economic, or social have been, at times, neglected. The manufacturing sector, as one of the most polluting sector, felt the urge to adapt to this industrial progress and find ways to produce with improved sustainability goals without compromising the quality of the final product and the production time. Industry easily understood the benefits of this greener approach, and, with this, new sustainable technologies started to emerge. Additive Manufacturing (AM) is one of those technologies that provide alternative sustainable paths to traditional manufacturing. In order to generalize the benefits of AM production in terms of sustainability, when compared to traditional processes, further investigations must be conducted. In this sense, the proposed work has the intention of finding the environmental impacts associated with a particular AM technique for the fabrication of metal parts, Wire Arc Additive Manufacturing (WAAM). A practical work based on the production of three different complexity metal parts considering an additive (WAAM) and a subtractive (Computer Numerical Control (CNC) Milling) manufacturing process is developed. To quantify the environmental impacts of both processes, the author resorts to the Life Cycle Assessment (LCA) methodology. The assessment is conducted in the SimaPro 9.2 software, accordingly to ISO 14044:2006 standard. The results allow a comparison between both types of manufacturing and enable the suggestion of measures to decrease the environmental footprint of WAAM. It was found that WAAM approach leads to a material saving ranging between 40% and 70% and an environmental impact reduction in the range of 12%–47%, compared to the subtractive approach for fabricating the 3 geometries considered in this study. The conclusions obtained are specific to this particular application and, once more, it is acknowledged that in order to reach a global understanding relative to this technology's environmental implications, extra research still needs to be made.

Geodesic Half-Maxwell Fish-Eye-Lens Antenna

We propose and implement a geodesic half-Maxwell fish-eye (MFE)-lens antenna. The lens was optimized using an in-house physical optics (PO) code adapted for generalized geodesic lenses. The final antenna design was validated with commercial electromagnetic simulation software. The antenna combines a modulated geodesic half-MFE lens and a transition to a linear flare, which is needed to preserve the linear polarization in the aperture. The antenna prototype, designed to operate in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{K}_{\mathrm {a}}$ </tex-math></inline-formula> -band, was manufactured with computer numerical control (CNC) milling and measured in an anechoic chamber. The design provides continuous beam scanning because of a mechanically actuated feed. Promising beam scanning properties are demonstrated in an angular range of ±45° with a scan loss below 3 dB, as well as good frequency stability from 26 to 32 GHz. Since the antenna is fully metallic, its radiation efficiency is high (approximately 90%).

High-Q 100 GHz Photonic Crystal Resonator Fabricated From a Cyclic Olefin Copolymer

This letter describes the design, fabrication, and characterization of an air-mode 1-D photonic crystal resonator (PCR) operating at 100 GHz. The PCR was fabricated from an inexpensive cyclic olefin copolymer (COC) using computer numerical control (CNC) milling. It is demonstrated that despite the lack of complete electromagnetic bandgap arising due to the low permittivity of the COC, it remains possible to realize a resonator with a high quality factor ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> -factor) of 2800 through shaping of the resonant field to minimize radiative loss.

Terahertz waveguide multiplexers: A review

AbstractTerahertz (THz) band, which owns abundant and underexplored frequency spectrum, has provided rich scientific and technological opportunities in numerous research fields, such as radio astronomy, atmospheric science and high‐speed communication. As one of the key components in THz systems, the multiplexer cannot only separate/combine different bands, but can also promote the development of THz instruments toward wider band and more multibands. Thanks to the high‐precision computer numerical control milling and micromachining technologies, a lot of THz waveguide multiplexers have been reported in recent years. According to the classification of design configurations, this article offers a brief overview on the developed THz multiplexers. In addition, the performance and system applications of different waveguide‐typed multiplexers are discussed. Therefore, this review will provide a valuable reference for the further development of THz waveguide multiplexers with high performance.

Comparative Study about Dimensional Accuracy and Surface Finish of Constant-Breadth Cams Manufactured by FFF and CNC Milling

In this work, the design, manufacture and measurement process of constant-breadth cams is presented. The motion law of the cam was designed by means of Bézier curves and the corresponding design desmodromic constraints. The cams were manufactured in two different materials employing two different processes: PLA cams with fused filament fabrication (FFF) and aluminium cams with computer numerical control (CNC) milling. The main aim of this work is to compare both types of cams regarding dimensional accuracy and surface finish, in order to evaluate if it would be possible to temporally replace a metallic cam with a plastic one during the repair of the first one. Dimensions were measured with micrometres and surface roughness with a contact roughness meter. The results show that, in diametral dimensions, similar dimensional error values were obtained for both the 3D-printed and the machined cams. However, in longitudinal dimensions, whose direction is perpendicular to the 3D-printed layers, the 3D-printed cams showed higher dimensional error than the machined ones. The average roughness Ra in the 3D-printed cams was 20 times higher than in the milled cams. According to the results, it would be recommended to temporally replace metallic cams with plastic ones in applications of low-power transmission. Given that in the literature little information is available about the measurement of 3D-printed desmodromic cams, this work will contribute to the study and analysis of this kind of 3D printed mechanism.

Life Cycle Assessment of Wire Arc Additive Manufacturing Products

The industrial progress over these years has led to fast, goodquality production. Despite this progress, the impacts related to such type of production, whether these are social, economic, or environmental, have not been, at times, studied extensively. The industry realized the importance of a greener approach and as a result, new sustainable technologies, such as additive manufacturing (AM), have emerged. To generalize the environmental benefits of AM over traditional manufacturing, methodologies like Life Cycle Assessment (LCA) are used. The proposed work has the intent of understanding and quantifying the environmental impacts associated with a particular AM technique for the fabrication of metal parts, Wire Arc Additive Manufacturing (WAAM). An LCA is conducted and, considering the same circumstances, the environmental impacts related to the production of 3 different metal parts are analysed. In order to understand the results obtained, Computer Numerical Control (CNC) milling, which is also used for the fabrication of metal parts, is equally considered. In this particular application, when compared to CNC Milling, WAAM proves to have a 12%-47% in the environmental impact, depending upon the geometry considered. The environmental hotspot identified for both processes is the production of the raw material.