Subtractive Manufacturing Research Articles

Automated Manufacturing Toolchain using Skill-based Digital Twins

Digital twins with a skill-based description are increasingly finding their way into industrial production. Their models link properties of a product with available process capabilities that are realized by resource skills. A matchmaking derives capable resources, e.g. for modular assembly systems. For capability-based planning in manufacturing, integration with computer-aided design (CAD) and computer-aided manufacturing (CAM) programs is missing. This paper presents an automated toolchain with focus on subtractive manufacturing using skill-based digital twins. Product-Process-Resource (PPR) models are used and enriched with subtractive manufacturing information and further relations. A configurator allows the design of the individual digital product twin, which can synchronously be generated as a 3D model using a CAD service. Necessary subtractive manufacturing steps including capable resources are then determined in a planning environment and fed into the CAM system. This allows an individual generation of machining code based on PPR information, which can be validated on a simulation model. The result is an automated tool chain of different software services, which are composed by a common description of the PPR model and the software services themselves. By defined models and interfaces the toolchain is not restricted to subtractive manufacturing but enables the integration of computer-aided everything (CAx) services.

Additive manufacturing of dental ceramics in prosthodontics: The status quo and the future.

This review aims to summarize the available technologies, material categories, and prosthodontic applications of additive manufacturing (AM) dental ceramics, evaluate the achievable accuracy and mechanical properties in comparison with current mainstream computer-aided design/computer-aided manufacturing (CAD/CAM) subtractive manufacturing (SM) methods, and discuss future prospects and directions. This paper is based on the latest reviews, state-of-the-art research, and existing ISO standards on AM technologies and prosthodontic applications of dental ceramics. PubMed, Web of Science, and ScienceDirect were amongst the sources searched for narrative reviews. Relatively few AM technologies are available and their applications are limited to crowns and fixed partial dentures. Although the accuracy and strength of AM dental ceramics are comparable to those of SM, they have the limitations of relatively inferior curved surface accuracy and low strength reliability. Furthermore, functionally graded additive manufacturing (FGAM), a potential direction for AM, enables the realization of biomimetic structures, such as natural teeth; however, specific studies are currently lacking. AM dental ceramics are not sufficiently developed for large-scale clinical applications. However, with additional research, it may be possible for AM to replace SM as the mainstream manufacturing technology for ceramic restorations.

Development of an Extraction Hood for Efficient Chip Collection during the Finishing Process of FFF 3D Printed Parts

Fused Filament Fabrication (FFF) has seen a rise in popularity for industrial and research applications due to freedom of design, comparably small costs and a short manufacturing time. However, the achievable surface quality and dimensional accuracy is still limited due to a hard to control and uncertain extrusion process. Thus, hybrid manufacturing offers the potential to improve the accuracy and roughness with subtractive manufacturing. Although several researchers have focused on recycling filament of defective prints, the recycling aspect of chips resulting from hybrid manufacturing did not receive the same attention. That is why in this work an initial step is taken for enabling an additional source for filament recycling by designing a chip collector. To optimize the capability of the system a systematic simulation-based design process is carried out. Particle trajectories obtained from high-speed video recordings were evaluated by means of particle tracking velocimetry (PTV). Subsequently two design concepts of an extraction hood were developed and analyzed using computational fluid dynamics (CFD). Additionally, particle trajectories were calculated and evaluated. Based on the simulation results one flow optimized concept is chosen which offers a simulated chip extraction rate of 99.9 %.

Patterned growth of two-dimensional atomic layer semiconductors.

Transition metal dichalcogenides (TMDCs), which are representative of two-dimensional (2D) semiconductors, have attracted tremendous attention over the last two decades. TMDCs are regarded as potential candidates in modern nano- and optoelectronic applications due to their unique crystal structures and outstanding electronic and optoelectronic properties. For practical use, 2D semiconductors need to be fabricated with diverse morphologies for integration into electronic devices and to perform different functionalities. Controlled patterning synthesis with programmable geometries is therefore highly desired. We review state-of-the-art strategies for the patterned growth of atomic layer TMDCs and their heterostructures, including additive manufacturing and subtractive manufacturing for patterning single TMDC materials and the introduction of other low-dimensional nanomaterials as growth templates or hetero-atoms for element conversion in patterning TMDC heterostructures. The optoelectronic and electronic applications of the as-grown monolayer TMDC patterns are introduced. Future challenges and the prospects for the patterned growth of 2D semiconductors are discussed based on present achievements.

Evolution of surface quality in micromilling Ti-6A1-4V alloy with increasing machined length

Micromilling is a subtractive manufacturing process that presents challenges due to scale effects and rapid tool wear. To understand the evolution of surface quality when increasing the machined length during the micromilling process, this study assessed the surface roughness, topography, and defects of slots micromilled on Ti-6A1-4V. For the experiments, 1 mm diameter flat end mills were employed, and the cutting parameters were varied using a full factorial design. Subsequently, the surface texture field parameter Sa was assessed every 20 mm, up until the machining length of 260 mm. The analysed results led to the conclusion that, for the adopted set of parameters and the machining length of up to 260 mm, surface roughness was not significantly correlated to the machined length in the micromilling process of Ti-6A1-4V, as the Pearson coefficient, obtained from the correlation analysis, was -0.052. However, the surface roughness was mainly influenced by feed rate (Pearson coefficient of 0.82), with higher feed rates leading to roug surfaces (up to Sa = 0.4 µm) duhere to the tool load increase that causes wider feed marks on the surface. Regarding the feed marks, they were affected by the tool rotational frequency due to system vibration. Additionally, surface defects of adhered material, smearing, tearing and side flow were observed. For lower feeds, material adhesion was the main type of defect observed, while higher feed rates favoured the side flow phenomenon.

Effect of build orientation on the wear resistance and hardness of denture teeth fabricated using digital light processing: An in vitro study.

This in vitro study investigated the effect of build orientation on the wear resistance and hardness of denture teeth fabricated using digital light processing (DLP) compared to other denture tooth materials. Disc-shaped specimens were prepared using denture tooth monomers and DLP devices in three build orientations: 0°, 45°, and 90°. Specimens of the same shape were fabricated using denture tooth materials for subtractive manufacturing, commercially available polymethylmethacrylate (PMMA) resin, and composite resin. The wear resistance was evaluated as the wear volume loss after 50,000 wear cycles using a ball-on-disc wear device in water for two-body wear and poppy seed slurry for three-body wear. The Vickers hardness values of the materials were measured. Two-way and one-way analyses of variance were performed for wear resistance and hardness, respectively, followed by Tukey's honest significance test. The interaction between the denture tooth resins and maximum wear volume was significant (P < 0.01). The 0° build orientation exhibited the lowest wear volume in the three-body wear test and the highest hardness among the three build orientations. The 0° DLP-fabricated specimens demonstrated significantly less wear volume than that of the PMMA specimens and a wear volume comparable to that of the milled specimens. However, the 0° DLP-fabricated specimens showed significantly lower hardness than that of the milled and PMMA specimens. The composite resin specimens exhibited the highest wear resistance and hardness. A 0° build orientation is recommended for DLP-fabricated denture teeth compared to 45° and 90° orientations to achieve greater wear resistance and hardness.

A novel direct reduction and alloying process for making additive manufacturing of titanium alloys greener

Additive manufacturing (AM) is considered an energy-efficient alternative to conventional subtractive manufacturing of metals. However, the high embodied energy of the feed materials undermines the merits of energy saving in AM. Spherical Ti-6Al-4V alloy powder, widely used in AM, is commercially produced by atomizing Ti alloys made from the Kroll process. This production route incurs high energy consumption due to low yield, the energy required to melt and break the molten metal into fine particles and make the primary titanium metal. This paper presents a novel, energy-efficient pathway for directly fabricating spherical Ti-6Al-4V alloy powder from oxides. In this process, raw metal oxides are reduced to form fine Ti-6Al-4V alloy powder, which is then granulated, sintered, and deoxygenated to produce the low-oxygen spherical powder. The integrated process is called the direct reduction and alloying (DRA) process. Spherical Ti-6Al-4V alloy powders produced by this process have low interstitial impurities, controlled particle size distribution, homogeneous compositions, and excellent flowability for AM applications. Energy consumption analysis suggests that the DRA process has the potential to significantly reduce the energy consumption of producing titanium alloy feedstock, thereby improving the environmental impact of additive manufacturing.

Design and simulation of a multisensory-multi-process end-effector for application to various kinematics

In the manufacturing industry, there is a growing need for flexible and interchangeable production systems. These systems must be capable of adapting to various processes and components. One of the central challenges is the development of versatile end-effectors. This paper focuses on designing and simulating a multi-process and multi-sensorial end-effector applicable to various kinematic systems, including machine tools (MT) and industrial robots (IR). The end-effector features a changeable process module suitable for additive, subtractive, and assembly processes. Its housing is fabricated using a combination of additive and subtractive manufacturing methods and employs a variety of materials. Emphasis is placed on lightweight construction, achieved through topology-optimized structures. The design is optimized to distribute force effectively throughout the operational process. A servo motor drives the end-effector’s spindle via a toothed belt, allowing for the automated insertion of different process modules into a hollow shaft. Moreover, the paper provides an initial outlook on integrating sensor technology to monitor the end-effector’s performance. For instance, strain gauges and accelerometers are utilized for data collection. These sensors are integrated within the end-effector structure. Furthermore, the concept of HSKi is discussed, enabling energy transfer from the spindle through the tool holder to the TCP.

Environmental Assessment of Metal Chip Recycling – Quantification of Mechanical Processing's Global Warming Potential

Material recycling is an essential lever for improving the sustainability of production processes. One way of reusing metal chips that occur as waste in machining or other subtractive manufacturing processes is to mechanically pretreat and remelt them. In mechanical pretreatment, the chips are separated from the cutting fluid by a centrifuge and then briquetted directly on site. This simplifies the handling and makes the transport and subsequent remelting more efficient than in thermal processing alone. The main objective of this work is to quantitatively assess the environmental impacts of the described recycling process, focusing on the global warming potential. Furthermore, recycling by means of mechanical chip processing is compared with alternatives such as thermal drying and primary material extraction. A parametric life cycle assessment (LCA) model has been developed for this purpose. The model considers equipment, material, throughput and location variations to analyze different use cases. The results of the LCA of an exemplary use case show that environmental benefits result from a higher bulk density during transport and a lower energy input during remelting due to a lower liquid content.

Subtractive and Additive Technologies in Fixed Dental Restoration: A Systematic Review

Today, computers and digital devices are an indispensable part of our daily lives, and dentistry is no exception. Dentistry has adopted a number of digital technologies, including CAD/CAM (computer-aided design and manufacturing) systems. The goal of the current study is to evaluate the current state of knowledge on dental alloy manufacturing using subtractive and additive techniques for metal ceramic restoration. On this topic, an electronic systematic review was conducted in various databases (Science Direct, PubMed, Web of Science, and Google Scholar searches), as well as a hand search of the scientific literature. Published work was collected, analyzed, and relevant articles were chosen for inclusion in this review from 2008 to 2021. The online databases were searched for articles published that appeared between 2008 and 2021, with no time or language constraints we grouped relevant search terms together, such as "Computer-Aided Design, CAD/CAM, dentistry, dental fabrication, restoration, additive manufacturing." We recognized publications individually and systematically screened titles, summaries, and complete texts of the obtained publications. The findings indicate that current knowledge is sufficient to recommend subtractive manufacturing for crowns and fixed dental restorations for routine clinical use, with improvements in each of the current metal-ceramic veneering materials and procedures. According to the review, several digital technologies, such as systems of computer aided design and aided manufacturing were used in different dental specialties. Application of CAD/CAM technology provided numerous benefits while posing few limitations.

Electrochemical Additive Manufacturing of Binary and Ternary Alloys at the Mircon Scale by Electrohydrodynamic Redox 3D Printing

The need for miniaturisation throughout many different industries brings classical subtractive manufacturing techniques to their limits. Additive manufacturing is able to overcome these limits which has made it a topic of interest in many scientific fields. This additional geometric freedom becomes increasingly important if feature sizes on the micron- or even nano-scale are desired. Multiple different techniques to fabricate device-grade metals at such length-scales have been reported [1]. As one of these techniques, electrohydrodynamic redox printing (EHD-RP) has shown promise to be a versatile fabrication tool [2, 3, 4] depositing dense, pure metallic structures at high deposition rates.In this contribution, we present our work on additively manufactured alloys. First, we introduce a novel EHD-RP approach using aqueous metal salt electrolytes instead of sacrificial anodes as ion sources. The use of metal salts not only expands the range of manufacturable metals, but also enables the fabrication of metal alloys with precise compositional control without the need for additives or a surplus of the less noble metal. We demonstrate this control by fabricating binary and ternary Cu-Ag, Cu-Zn and Cu-Ag-Zn alloys. The composition of the fabricated alloy exactly mirrors the composition of the aqueous metal salt solutions. These systems were chosen as a representative immiscible and miscible system, in order to study different growth mechanisms. Microstructural analysis of Cu-Ag alloys reveals the formation of a metastable mixed phase. Cu-Ag alloys were successively dealloyed to produce nano-porous Ag structures. The compositional control over the Cu-Ag alloy enables precise control of porosity in the dealloyed structures. These nano-porous Ag structures have also been tested as substrates for surface enhanced Raman spectroscopy.(1) L. Hirt, A. Reiser, R. Spolenak & T. Zambelli, Adv. Mater 2017, 29, 1604211(2) A. Reiser, M. Lindén, P. Rohner, A. Marchand, H. Galinski, A. S. Sologubenko, J. M. Wheeler, R. Zenobi, D. Poulikakos & R. Spolenak, Nat. Comm. 2019, 10, 1853(3) M. Nydegger, A. Pruška, H. Galinski, R. Zenobi, A. Reiser & R. Spolenak, Nanoscale 2022, 14, 17418(4) M. Menétrey, L. Koch, A. Sologubenko, S. Gerstl, R. Spolenak & A. Reiser, Small 2022, 18, 2205302

Towards Lunar In-Situ Resource Utilization Based Subtractive Manufacturing

In recent years, space agencies, such as the National Aeronautics and Space Administration (NASA) and European Space Agency (ESA), have expanded their research activities in the field of manufacturing in space. These measures serve to reduce limitations and costs through fairing size, launch mass capabilities or logistic missions. The objective, in turn, is to develop technologies and processes that enable on-demand manufacturing for long-term space missions and on other celestial bodies. Within these research activities, in-situ resource utilization (ISRU) and recycling are major topics to exploit local resources and save transport capacity and, therefore, costs. On the other hand, it is important to carefully consider which items can be brought and which must be manufactured on the Moon. Consequently, on-demand needs in future space missions are considered regarding frequency, raw material and required manufacturing processes according to investigations by ESA and NASA. In conclusion, manufacturing in space state-of-the-art shows a strong focus on additive processes, primarily considering semicrystalline or amorphous plastics. The subtractive processing of metallic or ceramic materials, in turn, currently represents a research gap. Consequently, an approach for in-situ resource utilization-based subtractive manufacturing in space is presented to supplement the existing processes. The latter uses a high-pressure jet of water, with regolith simulate as abrasive in suspension, being directed at the workpiece, which is moved to separate metal and glass. Proof-of-concept results are presented, including suitable process windows, achieved cutting geometries, as well as the effects of parameter variations on the system technology and consumables used. The focus of the investigations supplements the general requirements for the design of machine tools for space applications with inertial process-specific boundary conditions as a step towards higher technology maturity.

Prediction of residual strain/stress validated with neutron diffraction method for wire-feed hybrid additive/subtractive manufacturing

Hybrid manufacturing integrates additive manufacturing (AM) and subtractive manufacturing in the same machine. The integration of the two processes enables the creation of complex geometry, further reduces material waste, and decreases lead time. Moreover, this in-envelop method enables an interleaved printing strategy in which the part is partially AM printed and then machined repeatedly. This method is not available in either traditional manufacturing or AM technologies. Nevertheless, measuring and controlling of distortion and residual stress are still challenging due to highly varying process conditions and limited access to the machine during hybrid additive/subtractive manufacturing processes. Moreover, the residual stress measurement is ex-situ process, so it only gives information at the final stage of stress evolution. Therefore, it’s nearly impossible to know the AM induced residual stress distribution before the machining process in hybrid additive/subtractive process. In this prospective, numerical modeling can be an effective tools to overcome those challenges. However, the modelling/simulation methods for fully-coupled additive and subtractive operation has not reported to the best of our knowledge. In this work, we developed a comprehensive simulation method using finite element method (FEM) for fully-coupled additive and subtractive manufacturing process. The results were validated with strain measurements by neutron diffraction in two different machining conditions: hot-machining and cold-machining. The validated model was used to investigate how machining affects part distortion and evolution of residual strain/stress during fabrication. Alternating tensile-compression longitudinal (ε11, x-direction) strains and stresses along the build direction showed the physical interaction of additive and subtractive steps in the interleaved strategy. The alternating pattern was found in both the model and neutron diffraction measurements. This work’s findings can be used to develop strategies to control of part distortion and residual stresses in the hybrid additive/subtractive manufacturing process.

Tribological Properties of Additively Manufactured Al-Si Alloys and Steels

Metals are prone to wear through the separation of wear debris particles as well as the plastic displacement of surface and near-surface material. Particle sizes range from millimetres to nanometres. Erosion is the gradual, layer-by-layer destruction of a metallic object's surface brought on by mechanical pressure or electrical discharges. Metals erode as a result of surface friction, wear, cavitation, and the influence of powerful gas or liquid currents on a surface. Jet engines, nuclear reactors, steam turbines, and boilers might all suffer damage from erosion. By enhancing process technology or unit design, using better materials, and applying heat treatment, it is possible to strengthen the resistance of components against erosion. AlSi10Mg is a hypoeutectic alloy that may be additively manufactured due to its limited solidification range, which reduces hot cracking susceptibility during cooling. Complex bulk and open-cell structures with outstanding strength ratio (strength-to-weight ratio) and good formability may be created using additive manufacturing of aluminium alloys, particularly AlSi10Mg. Carbon, manganese, sulphur, silicon, phosphorus, chromium, nickel, copper, and niobium are all present in the pH grade of 17-4. This combination of high strength and corrosion resistance benefits a 17-4 PH stainless steel grade. It may be utilised effectively in a variety of applications due to its high tensile strength and exceptional corrosion resistance.Powder bed fusion is one of the most mature metal additive methods, and as such, it benefits from decades of industrial expertise. PBF can satisfy demands of creating a new component and need to iterate on ideas quickly or are searching for a more efficient procedure to produce sophisticated components. Material waste is reduced because building the part layer by layer reduces the majority of the waste associated with subtractive manufacturing processes. Any surplus powder is collected and recycled when the item is finished. This review researches about the wear and erosion behaviour of Al-Si Alloy and steels printed using additive manufacturing methods. Finally, the findings of this review are summarised, and recommendations are made for future research aimed at resolving current issues and advancing technology.

VASCO: Volume and Surface Co-Decomposition for Hybrid Manufacturing

Additive and subtractive hybrid manufacturing (ASHM) involves the alternating use of additive and subtractive manufacturing techniques, which provides unique advantages for fabricating complex geometries with otherwise inaccessible surfaces. However, a significant challenge lies in ensuring tool accessibility during both fabrication procedures, as the object shape may change dramatically, and different parts of the shape are interdependent. In this study, we propose a computational framework to optimize the planning of additive and subtractive sequences while ensuring tool accessibility. Our goal is to minimize the switching between additive and subtractive processes to achieve efficient fabrication while maintaining product quality. We approach the problem by formulating it as a Volume-And-Surface-CO-decomposition (VASCO) problem. First, we slice volumes into slabs and build a dynamic-directed graph to encode manufacturing constraints, with each node representing a slab and direction reflecting operation order. We introduce a novel geometry property called hybrid-fabricability for a pair of additive and subtractive procedures. Then, we propose a beam-guided top-down block decomposition algorithm to solve the VASCO problem. We apply our solution to a 5-axis hybrid manufacturing platform and evaluate various 3D shapes. Finally, we assess the performance of our approach through both physical and simulated manufacturing evaluations.

Design and analysis of wrist hand orthosis for carpal tunnel syndrome using additive manufacturing

Among additive manufacturing (AM) techniques, fused deposition modelling (FDM) is one of the extensively used techniques which add materials layer-by-layer to make three-dimensional parts, unlike subtractive manufacturing which involves the removal of materials. It is widely used in the field of orthotics to build customized products with less material waste and time. This study focuses on a detailed investigation of the designing to manufacturing of FDM-built wrist hand orthosis using nylon material. Patients with carpal tunnel syndrome, a condition caused by compression of the median nerve in the wrist, employ these aids to alleviate their symptoms. First 3D scanning wrist and hand was performed to collect the required data. Which is then further modeled and refined in CAD software’s. Topology optimization was performed to reduce the weight of the wrist hand orthosis. Static analysis of the final design is then performed to evaluate the performance using Von Mises stress, displacement and factor of safety. The results showed that nylon is found to be suitable material for wrist hand orthosis. At 50 N forces the maximum Von Mises Stress developed are 15 MPa which is lower than its yield strength i.e. 42.22 MPa. The maximum displacement produced is also smaller i.e. 0.102 mm, while the minimum safety of factor is 2.82. A carpal tunnel syndrome patient participated in a case study using the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) questionnaire to assess satisfaction with a 3D-printed nylon wrist hand orthosis. Results showed relatively good satisfaction and highlighted the orthosis's positive impact on design, lightweight nature, and ease of use.

Status of 3D Printing Technology for Preparing Bioceramic Materials

3D printing technology has great advantages in small batch and personalized customization, so it has attracted much attention in the biomedical field. The consumables available for 3D printing include polymer, metal, ceramic and derived materials. Biomedical ceramics, with high melting point and poor toughness, are the most difficult materials to be used in 3D printing. The progress of 3D printing ceramic preparation process using ceramic powder, ceramic slurry, ceramic wire, ceramic film and other different raw materials as consumables are reviewed, and the surface roughness, size, density and other parameters of ceramics prepared by SLS, 3DP, DIW, IJP, SL, DLP, FDM, LOM and other different processes are compared. The study also summarizes the clinical application status of 3D printed bioceramics in the field of hard tissue repair such as bone tissue engineering scaffolds and dental prostheses. The SL ceramic additive manufacturing technology based on the principle of UV polymerization has better manufacturing precision, forming quality and the ability to prepare large-size parts, and can also endow bioceramics with better biological properties, mechanical properties, antibacterial, tumor treatment and other functions by doping trace nutrients and surface functional modification. Compared with the traditional subtractive manufacturing process, the bioceramics prepared by 3D printing not only have good mechanical properties, but also often have better biocompatibility and osteoconductivity.

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.

Micromechanical Models for FDM 3D-Printed Polymers: A Review.

Due to its large number of advantages compared to traditional subtractive manufacturing techniques, additive manufacturing (AM) has gained increasing attention and popularity. Among the most common AM techniques is fused filament fabrication (FFF), usually referred to by its trademarked name: fused deposition modeling (FDM). This is the most efficient technique for manufacturing physical three-dimensional thermoplastics, such that FDM machines are nowadays the most common. Regardless of the 3D-printing methodology, AM techniques involve layer-by-layer deposition. Generally, this layer-wise process introduces anisotropy into the produced parts. The manufacturing procedure creates parts possessing heterogeneities at the micro (usually up to 1 mm) and meso (mm to cm) length scales, such as voids and pores, whose size, shape, and spatial distribution are mainly influenced by the so-called printing process parameters. Therefore, it is crucial to investigate their influence on the mechanical properties of FDM 3D-printed parts. This review starts with the identification of the printing process parameters that are considered to affect the micromechanical composition of FDM 3D-printed polymers. In what follows, their (negative) influence is attributed to characteristic mechanical properties. The remainder of this work reviews the state of the art in geometrical, numerical, and experimental analyses of FDM-printed parts. Finally, conclusions are drawn for each of the aforementioned analyses in view of microstructural modeling.

Design Strategies towards the Optimization of 3D Additive Manufactured Lattice Structures

Additive manufacturing (AM) techniques are based on the process of joining materials, layer upon layer, differently from subtractive manufacturing methods. The design for AM allows for the creation of complex shapes as well as for the improvement of the performance of critical components in several fields, spanning from aerospace and automotive to biomedical applications. On the other hand, unlike man-made high load-bearing capacity devices, which are usually dense solids, nature uses mesoscopic or microscopic cellular structures as a fundamental support for the design. The increasing applications of AM in industrial production have led to product reimagination from a novel standpoint, enabling the fabrication of advanced lattice structures using polymer-based materials. Over the past few years, many efforts have been made to develop strategies for finding the design which is best suited to the requirements. In the current research, specific design scenarios were explored, the aim being to develop novel lattice structures for energy absorption, using an AM technique (i.e., fused deposition modelling) and a modified Acrylonitrile Styrene Acrylate (ASA)-based material. The fabricated structures were preliminarily analysed by means of compression tests.