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The promising routes of metallic additive manufacturing favor the fabrication of refined functional components. Nonetheless, dealing with the Laser Powder Bed Fusion (L-PBF) parameters and costs for making the most of this technology is still an issue. The challenge gets bigger when considering less explored parameters, such as the process atmosphere and build location. So, this study aimed to address the main differences in microstructure, crystallography, mechanical properties, and surface finishing of maraging steel components manufactured under two different atmospheres (N2 and a mixture of 75%Ar-25%He atmospheres) and three build locations arranged along the gas flow direction. Based on experimental characterizations, the porosity fraction, microstructural constituents and metallurgical flaws, phase composition and martensite matrix crystallographic parameters, macrotexture, mechanical properties, roughness, and surface residual stress were investigated and compared for the different manufacturing conditions. The porosity fraction had the most expressive changes with the gas type and the build location, reaching a 53% overall reduction under N2 and a 112 to 302% rise for the front located sample compared to the others. The underlying mechanisms involved in the observed results, mainly related to process by-products behavior, were discussed. Broadly, the N2 atmosphere stands out over the analyzed properties. These findings underscore the role of atmospheric selection in the LPBF process, considering the overall quality and performance of the fabricated material and the possibility of cost reduction. [ABSTRACT FROM AUTHOR]

Injection moulding has been a pivotal technology in the mass production of polymer optics for many years. The surface quality of the moulding inserts exerts a significant influence on the quality of the optics produced. In the production of micro-structured polymer optics, such as Fresnel lenses, conventional isothermal injection moulding is unable to achieve the requisite surface accuracy. Variothermal injection moulding allows for improved surface accuracy and reduced residual stresses, but increases technical effort and cycle times. To reduce the cycle time and residual stresses of variothermal injection moulding, the potential of additive manufacturing of Al-40Si for the fabrication of moulding inserts is investigated. In order to achieve these objectives, the offered design freedom of additive manufacturing is investigated with a view to developing optimised conformal cooling channels. Numerical methods will be used for thermal and structural analyses. The performance of the newly developed moulding insert is evaluated experimentally by thermographic measurements and the measurement of stress birefringence on replicated PMMA samples. [ABSTRACT FROM AUTHOR]

Additive manufacturing technology has fostered its significant application in soft robotics fabrication due to the design freedom and ease of realizing complex geometries. The selection of an appropriate additive manufacturing process (out-of-material extrusion, vat photopolymerization, and powder bed fusion) is vital for the fabrication of soft robotics as the process greatly influences the quality of the part further affecting the functionality and service life. These pneumatically actuated robots in their service life are subjected to fatigue loading and handling of very delicate tasks; thus, the porosity (including pores characterization) and surface roughness are two critical quality parameters which should be considered while choosing the fabrication process. In this study, a three-way decision-making (a multi-criteria decision-making tool) approach is implemented for selecting an appropriate additive manufacturing process for the fabrication of high-quality parts for soft robotics applications. The results (ranking of AM processes) obtained using the proposed approach are compared with the conventional decision-making techniques, namely TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution), MOORA (Multi-Objective Optimization by Ratio Analysis), and VIKOR (VIseKriterijumska Optimizacija). The sensitivity analysis carried out in this work also suggests that three-way decision-making is as effective as other MCDM tools and the vat photopolymerization process is the most suitable out of all for fabricating TPU actuators. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) technologies have transformed manufacturing, by providing greater control over material deposition and consumption. Thanks to greater customization and their high strength-to-mass ratio, the AM of composite materials has significantly grown over the past few years. The main focus in this research area is improving printing precision and higher production rates. However, there is a lack of thorough analysis on the energy consumption of fused filament fabrication (FFF) machines for composite manufacturing, especially when associated with mechanical and economic aspects. We designed an experimental method, based on flow analysis for measuring the impact of temperature parameters on total cost, energy consumption, and tensile resistance of composite parts made by FFF. The user should be able to improve FFF efficiency regarding economic, energy, and technical aspects and obtain recommendations for setting up and using the machine. This study confirms that combining traditional economic and technical indicators (total cost and tensile resistance) with emerging energy indicators (specific energy consumption) can be successfully applied to additive manufacturing to provide an overview of printing parameters impact. Results are yielding information to support optimization investigations depending on the need and goal. For example, two tested parameter combinations that offer similar tensile properties (4% reduction in tensile resistance compared to the best combination) show a 20% difference with lower energy consumption. [ABSTRACT FROM AUTHOR]

This study aims to design a stretchable metasurface system that can adaptively change its wettability using additive manufacturing. The system consists of a stretchable specimen with micro-surface patterns and a bi-layer actuator based on compliant mechanisms. Both the specimen and actuator are manufactured using fused filament fabrication additive manufacturing methods. In the proposed system, the actuator stretches the specimen to modify the aspect ratios of the surface patterns. These changes in aspect ratios reduce the air gaps at the liquid/solid interface, which weakens the hydrophobic properties of the specimen surface. To investigate the effect of changes in pattern aspect ratios on surface wettability, experiment is conducted by dropping water droplets onto the specimen while the actuator stretches it. The contact angles of the droplets are measured to quantify the changes in wettability. Additionally, finite element simulations are performed to analyze the specimen strain distribution under various deformation conditions. This allows the evaluation of precise elongation values and prediction of surface wettability, displaying the potential for surface wettability control. These findings support the implementation of additive manufacturing to fabricate a stretchable metasurface system with adaptive wettability. [ABSTRACT FROM AUTHOR]

In this work, processes such as additive digital manufacturing (ADM) and precision casting are presented as alternative methods to manufacture aluminum foams with ordered open-pore morphology. Digital modeling of cellular structures with defined regular patterns was manufactured with ABS and wax and then melted in aluminum A356 alloy by a replication casting process. To guarantee the complete filling of the mold, a simulation by the Flow-3D program was made. This computational tool allowed to determine the temperature values of both melting and the mold temperature. The simulations revealed potential defects in the metal foams to be obtained, which were evidenced by the cast pieces processed after as a validation test. The results show that the casting process carried out supported by a computational fluid dynamics (CFD) simulation allows understanding the effects of the simulated parameter process, optimizing the parameters involved in the infiltration process, and establishing the conditions for obtaining a sound piece of open-cell aluminum foam with truncated octahedron pores shape. The established manufacturing process conditions can be used to produce lattice structures with multifunctional uses such as impact and blast-proof devices, vibration attenuators, or where enhancement of heat transfer could be needed. [ABSTRACT FROM AUTHOR]

Phononic crystal (PnCs) is one of the metamaterials focusing on the wave controls. The fabrication of this metamaterial is the key for its further industrial applications. Due to the advantage on the direct combination of computer-aided design, additive manufacturing (AM) is one of the most efficient manufacturing technologies for the fabrication of this wave controlling metamaterial. Here we reviewed the recent applications of AM on the fabrication of the wave-controlling metamaterials. The new features generated from the printing of the metallic parts like quick temperature changes in heating and cooling and re-melting and reheating were introduced. The theoretical and numerical developments on the printing of alloys were combined with the existing knowledge on metallurgy for the explanations of the changes of mechanical properties. The variations of mechanical properties, the residual distortions, and the property-oriented design of AM were introduced with the focus on the shift of band gap characteristics from the theoretical design in the wave-controlling metamaterials. The relationship between the process parameters and the structural performance of the wave-controlling metamaterials and the mechanical properties of the AM objects were mainly summarized. [ABSTRACT FROM AUTHOR]

As a promising technology capable of transforming the conventional manufacturing techniques, the use of additive manufacturing (AM) has span beyond the prototyping it was initially known for, and its use is currently revolutionising the future of the manufacturing and research world. A review of some of the advances made in the additive manufacturing of polymers and their composites is presented in this paper. Some of the advantages and disadvantages of the different AM techniques used in polymer composites (PC) fabrications are presented, and the different areas of applications of the AM fabricated PC are highlighted. Also highlighted are some of the potentials and challenges associated with the fabrication of components using 4D printing. Finally, the paper presents the prospects and the endless opportunities that abound with the AM of polymeric materials. [ABSTRACT FROM AUTHOR]

Transdermal drug delivery using hollow microneedle enables creating small, wearable and minimally invasive closed-loop system. Polymer hollow microneedles are preferable because they are cost-effective and easy to manufacture. SU-8 is chosen for creating the hollow microneedles as it is a biocompatible photopolymer with robust mechanical properties. Previously reported SU-8 microneedles either use melt casting process for coating SU-8 which is laborious or do not have monolithic structures, thereby making these mechanically weak and difficult to integrate. To the best of our knowledge, for the first time, we report the use of a single-step spin coating process to achieve the desired thickness of SU-8 while using UV lithography to create a monolithic microneedle array. Three types of microneedles were fabricated with outer dimensions varying from 90 to 180 μm, and lumen dimensions ranging from 60 to 80 μm and needle height of 600 μm. These needles are fabricated in a 10×10 array with a platform thickness of 300 μm. Geometrical, mechanical and fluid flow characterisations are carried out for the fabricated arrays. We report the use of a non-destructive evaluation method to characterise the lumen of the fabricated microneedles. The fabricated needles are robust and offer low resistance to fluid flow. The triangular needles can withstand a bending load of 0.2 N and an axial load of 0.7 N. The needles with circular lumen offer least resistance to fluid flow of 0.2 Pa-min μL−1. [ABSTRACT FROM AUTHOR]

Additive manufacturing is a promising tool that has proved its value in various applications. Among its technologies, the fused filament fabrication 3D printing technique stands out with its potential to serve a wide variety of applications, ranging from simple educational purposes to industrial and medical applications. However, as many materials and composites can be utilized for this technique, the processability of these materials can be a limiting factor for producing products with the required quality and properties. Over the past few years, many researchers have attempted to better understand the melt extrusion process during 3D printing. Moreover, other research groups have focused on optimizing the process by adjusting the process parameters. These attempts were conducted using different methods, including proposing analytical models, establishing numerical models, or experimental techniques. This review highlights the most relevant work from recent years on fused filament fabrication 3D printing and discusses the future perspectives of this 3D printing technology. [ABSTRACT FROM AUTHOR]

Additively fabricated parts can be manufactured to a near-net shape and typically only have to undergo finish operations to achieve the desired tolerances and surface finish. As heat-resistant super alloys (HRSA) are particularly difficult to machine, additive manufacturing techniques for fabrication of HRSA workpieces are of high interest. However, additively fabricated parts exhibit different properties than conventionally manufactured counterparts, including variations in machinability depending on their build direction and processing parameters. Machining force modeling for additively fabricated materials should be developed for making a correct choice of machining strategy and cutting parameters. A mechanistic model for cutting force prediction is proposed in this work. Mechanistic force modeling methodology was presented for different build orientations and discussed in detail. Validation of model output for uncut chip thickness and cross section area was performed with the use of 3D CAD uncut chip models. In-depth experimental testing was conducted to gather force data for modeling and evaluation purposes. The effects of feed rate, cutting speed, scan strategy rotation, and cutter-workpiece orientation were analyzed and discussed. Modeling results were compared with gathered experimental data, showing a good agreement of simulation and experimental results, proving the validity of proposed mechanistic force model for machining additively manufactured material. [ABSTRACT FROM AUTHOR]

This study fabricates a roughing electrode of electrical discharge machining (EDM) using a rapid prototyping (RP) system and investment casting technology, which reduces the overall time that is required for fabrication and the cost of the manufacturing process for a selected electrode. Pro/E (3D CAD) software is used to design the electrode prototype, which has a complex appearance, and to transform the CAD model into stereolithography (STL) format. An RP machine (Zcorp 402 3DP) is used to construct a gypsum-based powder model. After a sealing process using the permeation of resin, the water resistance and strength of the gypsum-based material are increased. The manufacturing process then involves creating a wax model with a gypsum electrode that is strengthened by resin permeation by casting a vulcanized silicone molding. The brass electrode is fabricated using investment casting technology. The results of an EDM test show that the brass electrodes with RP that are manufactured perform well and the total time that is required to machine the EDM electrode using RP is 15.8% less than the time that is required for a CNC machining process. [ABSTRACT FROM AUTHOR]

Material shrinkage commonly occurs in additive manufacturing and compromises the fabrication quality by causing unwanted distortions or residual stresses in fabricated parts. Even though it is known that the resulting deformations and stresses are highly dependent on the writing trajectory, no effective strategy for choosing suitable trajectories has been reported to date. Here, we present a path to achieve this goal in direct laser writing, an additive manufacturing method based on photopolymerization that commonly suffers from strong shrinkage-induced effects. First, we introduce a method for measuring the shrinkage of distinct direct laser written lines. We then introduce a semi-empirical numerical model to capture the interplay of sequentially polymerized material and the resulting macroscopic effects. Finally, we implement an artificial neural network to evaluate given laser trajectories in terms of the resulting part quality. The presented approach proves feasibility of using artificial neural networks to assess the quality of 3D printing trajectories and thereby demonstrates a potential route for reducing the impact of material shrinkage on 3D printed parts. [ABSTRACT FROM AUTHOR]

Despite significant advances and established advantages of material extrusion additive manufacturing, limitations still exist regarding ability to increase productivity and still maintain high shape fidelity and defect-free parts within the range of process parameter values that a 3D printer may support. In the present study, a predictive process-planning tool to balance productivity and quality of fabricated parts according to user's requirements is developed. Taguchi design of experiments (DoE) method is employed in order to determine the process parameters that impact shape fidelity in terms of material deposition stability that results in surfaces of acceptable flatness and defect-free parts. The development of four well-documented fabrication defects is quantified by CAD-to-part 3D comparison. Then, analysis of variance (ANOVA) was performed to reveal, characteristically, that, even though reduced speed generally results in improved shape fidelity, defects arise when small layer thickness is also set. On the other hand, increased layer thickness may be coupled with moderate material deposition speed to improve process productivity without sacrificing part shape. A highly reliable artificial neural network (ANN) is constructed in an optimum way and trained on the previous experiments with the aim to predict shape fidelity across the entire factor level range. Hence, material flow rate which is a function of investigated factors is provided with direct feedback by the ANN regarding possible defects or deteriorated part shape. The method presented lays the basis for robust process optimization on any 3D printer. [ABSTRACT FROM AUTHOR]

Conventional nasal prosthesis fabrication is highly dependent on the artistic skills of dental technologist. Present manufacturing process is laborious and time consuming. Fast prosthesis fabrication is required for patient with nasal defect to start an early rehabilitation process. This study attempted to explore the feasibility of an affordable FDM-based 3D printer for nasal prosthesis fabrication. Nose model was selected from a digital library followed by mould designing and printing prior to silicone moulding process. With an acceptable aesthetic outcomes and fast production time, the FDM-based 3D printer could be an alternative for indirect nasal prosthesis fabrication. [ABSTRACT FROM AUTHOR]

High porosity will bring about a great deal of contributions for metal-bonded grinding wheels. In this research, cellular structures, including octahedron, truncated octahedron, and stellated octahedron, are chosen as porous structures for a grinding wheel and fabricated using selective laser melting (SLM) with diamond/AlSi10Mg mixed powders. Moreover, the microstructure and bonding condition of SLM-fabricated composite are investigated. Additionally, morphological properties, mechanical properties, and permeability of three different porous structures are studied and compared with each other based on experiment and simulation. It is revealed that the microstructure of SLM-fabricated composite exhibits anisotropic due to the layered manufacturing essence. Furthermore, the cladding state of diamond grits is good and strong interface forms between diamond and AlSi10Mg. Besides, both mechanical performance and permeability of octahedron structure are the best, making it a potential structure for a high-performance porous grinding wheel. [ABSTRACT FROM AUTHOR]

Ultra-thin wafer with high quality was obtained by a new processing technique, which combined ultrasonic wet etching, temporary bonding, and chemical and mechanical polishing (CMP). In order to obtain a warp-free thin wafer, the pristine silicon wafer was subjected to initial thinning by ultrasonic wet etching. The temporary bonding was then conducted to anchor the wafer and ensure a stress-free de-bonding of the polished ultra-thin wafer from the supporting wafer. The subsequent CMP was applied to further reduce the thickness and roughness of the wafer. Measurements showed the as-fabricated ultra-thin wafer had an average thickness of 76 ± 2 μm, an average surface roughness of 0.32 nm, and a compressive stress of 101.4 MPa. The as-fabricated ultra-thin wafer showed improved overall appearance, with no obvious breakage, deformation, or damages on the surface. [ABSTRACT FROM AUTHOR]

Micro punching process is suitable for mass production of micro parts. It is a challenge to fabricate micro punching mold with complex cross-sectional shape on-machine. The micro punching system's structure design has to meet the requirement of large punching force. In this study, a micro punching system has been developed with a micro electrical discharge machining (EDM) module. A series of machining operations, from the fabrication of micro molds to punching, have been completed with no secondary clamping error. The micro die and reversed electrode are prepared using micro EDM milling. The micro punch is fabricated using reversed electrode. The punching clearance is around 11 μm. Complex shape punched holes and blanked parts have been successfully fabricated on copper, brass, 304 stainless steel, and 3J21 alloy. After punching, there was no damage on the edges of micro die and micro punch. The key dimensional error of blanked part varies by different materials, which is less than 2.5 μm. [ABSTRACT FROM AUTHOR]

Fused deposition modeling (FDM) is one of the most common additive manufacturing (AM) techniques for fabricating prototypes as well as functional parts. In this technique, several parameters may influence the part quality and consequently mechanical properties of fabricated components. In this paper, an experimental investigation on effects of fabrication temperature as one of the influential parameters on mechanical properties of manufactured parts is presented. A series of specimens fabricated at temperatures ranging from 180 to 260 ∘C were used for this investigation. X-ray computed tomography (CT) was used in order to non-destructively analyze the internal geometry of the specimens especially the bond between extruded filaments. Finally, the specimens were subjected to a uniaxial tensile load for evaluation of mechanical properties. The results showed that the specimens fabricated at lower temperatures have relatively lower tensile strength despite their considerably higher strain at break. In addition, the specimens fabricated at higher temperature range had significantly higher tensile strength because of the better bond between extruded filaments. The different mechanical responses were highly related to the internal geometry of the specimens and not necessarily the porosity. CT showed great potential as a non-destructive tool for investigation and development of FDM process. [ABSTRACT FROM AUTHOR]

Traditional punch and die stamping process are not capable of fabricating micro channels with high aspect ratio due to stress concentration and large thickness reduction. A thin sheet metal roll forming process using involute gears as rollers was proposed as a method to fabricate micro channels with high aspect ratio in this paper. Corresponding relations of gear-rollers and formed channel's geometrical morphology were firstly established as designing guidelines. Then, process characteristics, material deformation behavior, and process mechanism were studied by experiments and simulation. Micro channels with aspect ratios up to 1.0 was formed with thickness reduction lower than 18.7% using 0.1-mm SS316L metal sheets. And both experiments and simulation reveal that thickness reduction can be further lowered down by reducing friction. The forming process of a micro channel consists of two chronological states-forming stage and quitting stage which, respectively, determines the formability and dimension accuracy. Furthermore, process parameters and assembly errors were demonstrated to have great influences on the process' formability. This paper provides designing guidelines and process mechanism for thin sheet metal roll forming process as a promising method to fabricate micro channels with high aspect ratio. [ABSTRACT FROM AUTHOR]

A compact scatterometer has been build and tested at a production facility. The scatterometer is used to characterize the feature dimensions of injection molded polymer nanostructures and give on-site direct feedback to the operator on the produced quality. In this way, the injection molding process parameters are iteratively improved until accurate replication of the nanostructures has been achieved. The tests are carried out on 2-in. diameter samples with nearly 100 nanostructured areas, consisting of diffractive line gratings with different periods and orientations. It is found that different nanostructures require different process parameters to reach high replication fidelity. Scatterometry measurements are very fast, and will therefore not present a bottleneck when used for quality assurance during production. We furthermore examine the spatial variations in the replicated structures within molded polymer discs using an imaging scatterometer. We demonstrate that the imaging scatterometer is capable of characterizing the entire sample simultaneously, in contrast to the compact scatterometer which performs a local analysis based on measurements on the individual grating regions. [ABSTRACT FROM AUTHOR]

With the vast amount of capital invested in the wafer fab facility, how to effectively utilize the capacity is always a crucial challenge for semiconductor capacity planners. Currently, static capacity planning approach is widely applied to estimate the planned capacity; however, fab management believes that the ideal planned capacity is too optimistic and unachievable since many production constraints and the impact of abnormal events (e.g., machine breakdown) are not considered. Therefore, a managerial question must be solved: "What is the reasonable capacity plan?" Hence, this paper aims to develop an object-oriented capacity analysis and planning simulation (CAPS) model, which takes into account the production constraints, the operation characteristics of machine tools (e.g., multi-chamber), and the dispatching rules applied in a full-scale wafer fab. Then, capacity planners may employ CAPS model to study the impact of the available time (AT) and its fluctuation of critical machine tools to fab overall capacity and output performance (e.g., wafer out, utilization, work in process (WIP)); a reasonable planned capacity may be generated. Consequently, fab managers only need to watch attentively on the key machine tools, which will cause high impact on the throughput, and keep their promised AT level or increase AT level. [ABSTRACT FROM AUTHOR]

Slicing is the initial procedure in silicon wafer manufacturing process. The cost of slicing process is about 30% of the total cost of chip fabrication. The effective approaches to decrease slicing cost are to reduce the slicing kerf loss and to decrease the thickness and breakage ratio of sliced wafer. The resin-bonded diamond wire saw has the advantages of uniform of abrasive protrusion height and the manufacturing process less impact on the core wire strength. It is expected to achieve a narrow kerf and ultra-thin wafer slicing of silicon crystal ingot with resin-bonded diamond wire saw. The aim of this paper is to develop high-performance resin-bonded diamond wire saw. Based on the analysis of fabrication process of resin bond diamond wire saw, the device for resin-bonded diamond wire saw manufacturing is developed. The mold in the fabrication device ensures the consistency of the wire saw outer diameter and the uniform of abrasive protrusion height. A test device for constant force feed slicing is developed for the slicing performance evaluation of resin-bonded diamond wire saw. The components of the coating layer materials of resin-bonded diamond wire saw are investigated via orthogonal test. Choosing the material removal rate, wire saw wear rate, coating layer binding force, and sliced surface roughness as evaluation indexes, the performance of developed resin-bonded diamond wire saw is evaluated. The optimal component ratio of the coating layer materials of resin-bonded diamond wire saw is obtained, and the verification test of the optimal component ratio of the coating layer materials is performed. The results of this paper are useful for the development of smaller-diameter diamond wire saw and high-quality slicing of optoelectronic crystal ingot. [ABSTRACT FROM AUTHOR]

This paper reports a study on the development of bioactive glass powders for biofabrication of scaffolds by an additive manufacturing technique, three-dimensional printing (3DP). Several formulations of the glass were developed from the CaO·P2O5·TiO2 system and prepared on the basis of the results for the commercial powder characterization (average particle size, particle size distribution, microstructural and crystallographic analysis). For printing the glass models in the prototyping machine, a virtual model defined as the “standard model” was produced in commercial powder, and a systematic study of the relevant processing parameters (binder composition, formulation of powder, saturation level in the shell and core, bleed compensation, and printed layer thickness) was carried out in order to determine the most suitable conditions for the fabrication of porous structures for tissue engineering applications. The printed glass models were sintered through specific thermal programs and then characterized in terms of dimensions, structure, morphological features, and mechanical properties. Finally, the sintered models were submitted to mineralization tests in simulated physiological media. In this work, it was demonstrated that it is possible to use a printing machine to manufacture 3DP glassy porous structures with suitable features for tissue engineering applications as temporary scaffolds. The mechanical properties of the produced structures and its mineralization capability in physiological fluids suggest that they have potential to be used in bone tissue regeneration under low load-bearing situations. [ABSTRACT FROM AUTHOR]

The fabrication friction stir welded lap joints with Al 7075-T6 sheets is examined with a wide range of tool pin geometries and dimensions while comparing microstructures, bonded area geometry, hardness, and fracture load during overlap shear testing. The tool pin geometry and features significantly affected the hook geometry and thus weld strength and failure mode. A hook feature is prone to forming when a larger diameter or helical threaded tool pins are used and is shown to deteriorate overlap shear fracture load by reducing the bonded ligament in the upper sheet. This hook feature can be controlled by removing the helical threads on the tool pin and replacing these with concentric grooves. The overlap shear fracture load is controlled by a combination of the sheet thickness, the width of the bonded area, and extent of the hook feature. These factors are captured in a model which was shown to provide good predictions of the fracture load and can be used to select tool pin sizes for varying overlapping sheet thicknesses. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) is an emerging fabrication technology, which can offer a faster, versatile, flexible, easily customizable, and a cheaper production path, when compared to conventional manufacturing. There are different additive manufacturing techniques differentiated by the way of material is made available and melted in each layer. The Plasma Transferred Arc (PTA) is a promising AM technique because of its superior energy efficiency compared to laser-related processes. PTA allows to process materials both in powder and wire forms. Recent evidences suggested that the characteristics of the feedstock will impact the final microstructure and consequently the mechanical properties of the deposit. This work carried out a detailed analysis on effects of the feedstock form using PTA to build multilayers with wire and powder IN625 alloy. It considered the specific features of each feedstock for the processing and explored the relationship with the characteristics of the deposited multilayers. Powder plus arc and wire plus arc multilayers were analyzed using confocal microscopy, scanning electron microscopy, X-ray diffraction, and microhardness profile. It is shown that the microstructure and mechanical properties of a multilayer component are influenced on choice of the feedstock, mainly because of the differing parameters that will be required in their processing. [ABSTRACT FROM AUTHOR]

A method for fabricating a diamond tool with controllable edge radius was proposed. Using diamond tools with different edge radii at a low speed, nano-cutting tests were performed on single crystal silicon using a special instrument with SEM online observation. The chip morphology and deformation coefficient were analyzed to study the size effect of tool edge in the ductile-cut region. Electron back-scattered diffraction and laser micro-Raman spectroscopy were employed to detect subsurface damage in the machined silicon. The results indicated that the cutting-induced amorphous layer thickness is strongly dependent on the depth of cut and tool edge radius. In the beginning, the amorphous damage layer thickness decreases rapidly with the depth of cut, and then it increases gradually with the further increase in the depth of cut. The minimum amorphous damage can be obtained when the depth of cut is comparable to the tool edge radius. [ABSTRACT FROM AUTHOR]

Orientation determination is an essential process planning task in additive manufacturing (AM) since it directly affects the part quality, part texture, mechanical properties, build time, fabrication cost, etc. Evaluation method provides a simple and effective way to determine the optimum orientation of a part. However, the candidates are predesigned in the evaluation method, which results in limited candidate space and makes the qualities of evaluation results highly dependent on the qualities of the predesigned candidates; bad outcomes will be obtained due to the poor candidates. To this end, a feedback multi-attribute decision-making (MADM) model is proposed in this work. The feedback MADM model is an integration of two sub-models: MADM model and proportional-integral-derivative (PID) control model. MADM model aims to calculate the score of a given build orientation. Three criteria, surface roughness, support volume, and build time, are considered in this model, and the ordered weighted averaging (OWA) operator is applied for aggregation. In the PID control model, the finite candidate space is first expanded to infinity by quaternion rotation, then PID controller is applied to match the build orientation with the user’s requirements, that is, search for the part orientation whose score is consistent with the user expected score in the infinite alternative orientations. Four parts with different geometric structures are tested in the experiments, and evaluation and control features of the feedback MADM model are discussed. [ABSTRACT FROM AUTHOR]

Micro ball-end milling is an efficient and feasible method for the fabrication of microlens array molds which are widely applied in the aerospace, mechanical electronics, optics, and optoelectronics fields. The geometric structure of the micro ball-end mill plays an important role in micro dimple milling performance. The relief angle, as one of the major geometric parameters of the micro ball-end mill affects the sharpness of the cutting edge and determines friction between the tool and the workpiece. To investigate effective fabrication of a micro ball-end mill with different relief angles, this paper proposes a practical grinding method for the relief face validated by a grinding experiment, in which micro ball-end mills with relief angles of 10°, 20°, and 30° are fabricated. Furthermore, to analyze the influence of the relief angle on milling performance, micro dimple milling experiments on die steel material H13 with fabricated mills are carried out. The milling force, tool wear, and machining quality are measured and analyzed. The experimental results show that the micro ball-end mill with a 20° relief angle is more appropriate for micro dimple milling compared to the other two mills. [ABSTRACT FROM AUTHOR]

In order to realize the fabrication of micro cylindrical electrode with high rotation precision, the electrochemical etching process was studied and improved. Firstly, based on the principle of electrochemical etching, the effect of electrode rotation on the machining accuracy of cylindrical electrode was analyzed, which proved that electrode rotation can improve the rotation precision of the microelectrode. Secondly, according to the experimental induction and theoretical derivation, the function relationships among machining voltage, immersion depth, and rotation speed were established, and then the mathematical model for fabricating micro cylindrical electrode with high rotation precision was founded. Finally, the optimized combination of parameters is selected under the guidance of above model, and series of micro cylindrical electrodes with coaxial error below 1 μm are fabricated successfully, such as, the single-stepped cylindrical microelectrode with diameter of about 100 μm, aspect ratio of more than 20:1, and the multi-stepped cylindrical microelectrode with diameter below 20 μm, aspect ratio of more than 70:1. [ABSTRACT FROM AUTHOR]

This paper firstly focused on analyzing the machining accuracy of low-speed wire electrical discharge turning (LS-WEDT), and the practical machining is carried out via fabrication of micro parts. Firstly, the concept of LS-WEDT method is proposed and the rotating apparatus is designed and fabricated to make the low-speed wire electrical discharge machine realize the machining of rotary structures. Besides, the effects of machining parameter on roundness of YG8 hard alloy rotary workpiece machined by LS-WEDT are discussed. Besides, experimental results revealed that high consistent accuracy of rotary groove width can be obtained with the wire speed of 45 to 75 mm/s, feed speed of 0.8~1 mm/min, wire tension of 14~16 N, and the lower rotating speed is conductive to obtain high rotary groove accuracy. Furthermore, the intricate relationships of rotating speed, feed speed, and discharge energy for LS-WEDT process are revealed and optimum speed parameters are given for low and high discharge energy, respectively. Finally, using this new process, micro cylindrical shaft and the micro two-edged cutter are successfully fabricated. More importantly, the flexibility of LS-WEDT makes it have superiority in fabricating complicated structures not just limited to the simple rotary parts like cylinder. Consequently, experimental results indicated that spirals microelectrode with average diameter of 395.64 μm and length of 1673.64 μm and the three spirals micro-cutting tool with average diameter of 796.20 μm and length of 2011.15 μm can be firstly and successfully manufactured by LS-WEDT method. [ABSTRACT FROM AUTHOR]

The growth of additive manufacturing technology allows the fabrication of complete functional devices with complex geometries with ease and low cost. This technology allows the fabrication of pieces that could not be made in the past with traditional manufacturing techniques, in this case, bevel gears with exact spherical involute (ESI). Focusing on this issue, this paper presents a method for the geometric design and fabrication of practical industrial-like ESI bevel gears with variable surface detail. The definition of the tooth profiles on back cones is proposed introducing a projection procedure for straight and spiral toothing. An in-house-developed software package was developed to test the method, and a pair of plastic examples were fabricated on a generic 3D printer. A comparison between the fabricated pinion and its STL model was conducted for validation purposes. Mean deviations of 0.22 and 0.15mm were obtained for the whole model and for the contact surfaces comparison, respectively. Thus, the fabrication of bevel gears using AMT is achieved, and can be implemented to a specific application using a particular additive manufacturing technique. [ABSTRACT FROM AUTHOR]

Laser-accelerated metallic flyers can be used in microscale manufacturing processes by providing high-speed impact and shockwave to target materials. This study conducted microscale punching experiments using a laser-accelerated flyer for various mold sizes, workpiece thicknesses, and flyer thicknesses to investigate performance and failure characteristics of the punching process. In the case of a single flyer impact, punching was successful when the ratio of mold diameter to workpiece thickness exceeded 3. High-speed punching advantages, which improve punching quality as the shear zone increases and burrs become smaller, were validated. When flyer thickness was significantly reduced, punching performance deteriorated although higher speed could be realized, because the thinner flyer was difficult to maintain flatness during acceleration, resulting in inefficient forming pressure transfer to the workpiece. When the ratio of mold diameter to workpiece thickness was less than 3, punching was achieved through multiple flyer impacts. However, pressure transfer efficiency from the flyer to the workpiece was further reduced. Thus, punching performance could be improved by reducing the relative size of the flyer to the mold diameter. [ABSTRACT FROM AUTHOR]

Electron beam melting (EBM) is one of the growing processes of additive manufacturing technology (AMT) to fabricate 3D parts from various difficult-to-process materials such as titanium alloys. A major limitation of the EBM process is the poor surface finish of the produced parts which ultimately demands a subsequent subtractive method (secondary finishing operation) to improve the surface finish for shaping the part to be fit for-end use applications where high surface finish is commonly required. With respect to the EBM layer build direction, the fabricated part has different orientations with varying surface characteristics. Therefore, in order to perform secondary finishing operation (e.g., milling) there are different choices of EBM part orientation to select the direction of tool feed. In this research, 3D parts of titanium alloy (gamma titanium aluminide; γ-TiAl) are additively manufactured through EBM process. The effect of EBM layer/part orientation on the milling performance is further investigated in terms of surface finish improvement and edge chipping evaluation. It has been observed that the EBM layer/part orientation with respect to milling tool feed direction (TFD) plays a vital role in milling performance. Thus, a care must be taken to select the appropriate tool feed direction and layer/part orientation in order to achieve maximum surface finish with minimum edge chipping. The results revealed the vertical milling can be adopted as a secondary finishing operation to be performed on EBM produced parts of γ-TiAl and it allows to significantly improve the poor surface finish generated by EBM (Ra 31 μm). Furthermore, among the available part orientation choices, the part orientation in which the milling tool is fed across the EBM layer build direction is the best orientation resulting into high surface finish (Ra 0.12 μm) with relatively smooth edges (minimum chipping-off). [ABSTRACT FROM AUTHOR]

Robotic wire and arc additive manufacturing (WAAM) systems are required to provide predictable and efficient operations to fabricate solid metallic parts with high morphological fidelity and geometric accuracy. Since the metallic parts are fabricated based on a layer-by-layer principle, the interactions between the neighboring beads and layers strongly influence the geometric accuracy of the fabricated part. The layers-overlapping process has been studied and a traditional layers-overlapping model (T-LOM) has been published in the literature. This paper proposes a layers-overlapping strategy (LOS), based on which a revised layers-overlapping model (R-LOM) was proposed for the fabrication of multi-layer multi-bead (MLMB) components with homogeneous layers. A mathematical model for layers-overlapping is presented, which considers the material shortage areas at the edges of the layers. This is important since the material shortage areas result in a situation that the component width is smaller than the expected value. In addition, they will be accumulated when multiple layers are overlapped through normal unidirectional parallel (NUP) paths. The proposed LOS addresses two aspects: (i) the deposition amount of the first bead and the last bead in the lap layers should be increased and (ii) the deposition position of the first bead and the last bead in the lap layers should be moved towards the edges with a given offset distance. Validation experiments were designed and conducted to test the proposed concepts and models. The experimental results indicated that (i) the R-LOM enables the MLMB components to achieve the expected width and (ii) for components deposited with NUP paths, the R-LOM eliminates the effect of accumulation of material shortage areas on the first bead and increases the surface flatness. [ABSTRACT FROM AUTHOR]

Layered extrusion forming, a type of additive manufacturing technique, was applied in this study, using aqueous ceramic pastes to build near-net-shaped ceramic cores at room temperature. As an example, aqueous-based pastes of alumina using methylcellulose (MC) as binder were prepared, and layered extrusion forming method was employed to fabricate green alumina cores. Afterwards, post sintering was carried out to obtain ceramic cores with high strength. Pastes with alumina solid loading varying from 30 to 52 vol.% were dispersed by MC solutions and presented shear-thinning rheological behaviors. Solid loading had a significant effect on the processing of layered extrusion formation. Alumina pastes with 30 to 46 vol.% were not suitable for layered extrusion formation, while pastes with solid loading ranging from 48 to 52 vol.% could be applied successfully to the layered extrusion forming process. Pastes composed of 2 wt.% MC solution as binder and 50 vol.% solid loading generated specimens with best shape retention and surface consistency, and the height of each layer extruded was equally distributed. The green specimens exhibited slightly smaller dimensions than the designed ones, and sintered specimens showed linear shrinkage. Sintered specimens presented homogeneous morphology, and no gap between extruded filaments was observed. Specimens sintered at 1600 °C for 180 mins possessed best comprehensive performances and low thermal expansion, which could meet the requirements of ceramic cores in alloys casting. The systematic study of layered extrusion forming indicates that this method is a promising method to fabricate ceramic cores. [ABSTRACT FROM AUTHOR]

A novel process was used to fabricate a nanostructured polyurethane-based fabric. Batches were made by extruding the polymerised formulation while it was wound onto a mandrill to produce a spool of nanostructured 1.5-2.5-μm-diameter fibres. During this research, the ultrafine 2-μm-diameter polyurethane yarn has been nanostructured with 0.5, 0.75 and 1% (wt) graphitised multiwalled carbon nanotubes (MWCNTs). The yarn was subsequently weaved to form an electrically conductive fabric, which has ten times the electrical conductivity over its parent yarn. The process in which nanostructured fabric is manufactured is discussed together with its enhanced electrical conductivity characteristics. [ABSTRACT FROM AUTHOR]

Cylindrical plunge grinding experiments were carried out to compare the performance of non-grooved and grooved vitrified grinding wheels. The grooved wheels featured high-angle helical grooves with a 50% groove factor. Grinding forces, spindle power, workpiece roundness, and workpiece surface roughness were measured for five different infeed rates. It was observed that, for the conditions used in this research, the grooved grinding wheel reduced the resulting normal forces by 36%, tangential forces by 32%, spindle power by 29%, and specific energy by 28%, while increasing the workpiece surface roughness by 38%. The spark-in and spark-out time constants associated with the grooved grinding wheel were determined by analyzing the normal force data and found to be, on average, 21% lower than the non-grooved grinding wheel. The spark-in and spark-out time constants were also identified and used in a grinding force and infeed model to simulate the plunge grinding process. These simulations showed that, due to the combination of reduced forces and time constants when using a grooved wheel, improvements in overall plunge cycle time of up to 30% could be achievable. [ABSTRACT FROM AUTHOR]

High rotational speed friction stir welding (FSW) was successfully employed to weld 6061-T6 aluminum alloy thin plates. The effect of high rotational speed and fast transverse speed on temperature distribution, microstructure evolution, and tensile properties of friction stir welded 6061-T6 joints was investigated in detail. The high rotational speed with fast transverse speed had a significant influence on the peak temperature in the nugget zone (NZ). Increasing the rotational speed and decreasing the transverse speed could obviously improve the peak temperature in the NZ, but exhibit little effect on the heat-affected zone under high rotational speed FSW. The NZ was characterized as a significant refinement of the equiaxed grain. The number of precipitates, subgrains, and low angle grain boundaries in the NZ of high rotational speed FSW joint increased significantly due to moderate heat input and strain rate. The weld zone was seriously softened at low rotational speed, whereas it was alleviated at high rotational speed and was affected slightly by rotational speed and transverse speed. The excellent mechanical properties of the friction stir welded 6061-T6 joints were obtained at a combination of high rotational speed and fast transverse speed. The maximum tensile strength reached 301.8 MPa, 85.8% of the base material. [ABSTRACT FROM AUTHOR]

Abrasive water jet (AWJ) milling has speedily developed in popularity due to its adaptability and fast production of blind features like channels, pockets etc. But the surface property of AWJ-milled samples was found to be poor, restricting the process of being commercially used widely. In this work, a two-step methodology has been tried to modify the surface properties of Ti6Al4V substrate, which includes fast fabrication of miniaturised channel using AWJ technique followed by electrophoretic deposition (EPD) of hydroxyapatite-carbon nanotube (HAp-CNT) coating. The fretting wear test divulges the enhanced wear resistance of synergistically textured Ti6Al4V substrate with EPD HAp-CNT, due to its lower coefficient of friction (0.22 ± 0.0) and wear depth (− 18.1636 μm) when compared with that of textured Ti6Al4V (0.27 ± 0.005 and − 18.8221 μm, respectively). The coefficient of friction and wear depth were observed to be highest for bare Ti6Al4V sample (0.41 ± 0.007 and − 27.4985 μm, respectively). The observed increment in wear resistance is due to the textured channels trapping the wear debris and a decrease in the real contact area due to the coating of HAp-CNT. Thus, fabrication of micro-channels by AWJ combined with HAp-CNT coating may provide potential self-lubrication and enhance damage tolerance of Ti6Al4V alloy for biomedical and manufacturing applications. [ABSTRACT FROM AUTHOR]

This paper presents an experimental parameter optimization of electrochemical honing process (ECH) on the surface finish generation capability on cast iron of ASTM 35 with Brinell Hardness Hb 212. Taguchi orthogonal array of L9 experiment is used for optimization. Results from the main effect plot, regression analysis, correlation analysis, and interaction plots for the means indicate that best surface finish is obtained where the electric voltage is 15 V, electrolyte concentration is 20%, electrolyte pressure is 0.667 Mpa, and motor rotational speed is 60 rpm. However, significant variation is seen in the control of electric voltage as compared to the other three. Higher signal-to-noise ratio is observed on electric voltage followed by electrolyte concentration and electrolyte pressure signifying electric voltage is the determining factor. From standard deviation analysis, electrolyte pressure and electrolyte concentration are found to need close attention for better surface roughness along with electric voltage. The interaction plot for the three factors also indicates that electric voltage at highest level is more significant than the other factors. However, it is noted that the interaction of the electric voltage, electrolyte concentration, and electrolyte pressure significantly determines the effectiveness of the ECH process. Meanwhile, the level of control between electrolyte pressure and electrolyte concentration needs careful attention as the two factors work against each other. [ABSTRACT FROM AUTHOR]

Electrode wear has a major impact on the quality of the spot welding joint. It is important to evaluate the electrode tip condition based on a simple method. In this paper, the dynamic resistance is analyzed, and the relationship between the dynamic resistance and the radius of electrode tip is investigated. It is difficult to obtain the relationship between the electrode tip radius and real-time dynamic resistance. The dynamic resistance is represented by the sum of the squares of the real-time resistances in every half cycle. It is virtually impossible to research the electrode tip radius based on only one dynamic resistance of spot welding joint. The average value of dozens of dynamic resistances should be analyzed, and the means of 20 dynamic resistances are analyzed in this study. The average value of dynamic resistances from the first to seventh cycle during the nugget-growth stage has a strong corresponding relation to the electrode tip radius, which can be used to evaluate the electrode wear. [ABSTRACT FROM AUTHOR]

AA6061 aluminum alloy and AISI 316L steel were joined by friction welding with a specific steel collar fixed on aluminum side to control its expelling, flash morphology, and the formation of intermetallic compound (IMC) layer. The effects of friction time and welding groove were investigated by analyzing microstructure characteristics and mechanical properties. Eight typical zones could be found, and the existence of some certain zones depended on friction time. The thickness of IMC layers declined from 4 to 0.2 μm with friction time decreasing from 40 to 10 s, while a 15° welding groove machined on the end of steel helped realize thinning of IMC layer to a thickness of 0.3 μm. The conditions of 25-s friction time and processing of the 15° welding groove got best mechanical properties with average tensile strength of 166.32 MPa and average elongation rate of 9.47%. Tensile strength and elongation rate can improve 16.15 and 745.5%. [ABSTRACT FROM AUTHOR]

In the present study, an analytical transient cutting force model for high-speed ultrasonic vibration cutting has been developed. Micro-machining characteristics are figured out when both the tool nose round and round cutting edge are taken into consideration in the cutting mechanism. Four cutting zones (i.e., elastic recovery, plowing, shearing, and tool-chip friction) are proposed and analyzed to calculate the transient cutting force on each divided cross section in the normal direction of the cutting tool along the cutting edge. A non-free cutting coefficient is added to evaluate the influence of the tool shape on the cutting force compared to the orthogonal cutting model. Afterwards, transient cutting force and average cutting force are simultaneously measured. The results show that the shape and value of the transient cutting force correspond well with what was calculated using the proposed model, and the availability of the proposed model is verified by the cutting force shapes and values. [ABSTRACT FROM AUTHOR]

During the last decade, friction stir welding has various applications in the automotive, shipbuilding, and aerospace industry due to its versatility. More recently, there have been trials to combine FSW with ceramic nanoparticle reinforcement in order to form MMCs locally on the weld line. This combination could result to potential applications on the above industries. In the present study, optical and electron microscopy, as well as microhardness and tensile testing, were used in order to determine the effect that SiC and TiC nanopowders have on the weld nugget of AA6082-T6 butt welds. It is the first time that such a thorough study via TEM in combination with EDS was conducted for this alloy. Emphasis was given on the distribution of dislocations and on the presence of the intermetallic and reinforcing particles in the weld. It was found that the grain size of all the specimens was dramatically decreased due to the dynamic recrystallization phenomenon. This also provoked the dilution of a lot of the intermetallic particles of the base metal and the multiplication of the dislocations. Between the two reinforced specimens, the SiC presented higher elongation while the TiC presented higher microhardness. [ABSTRACT FROM AUTHOR]

The production of duplex stainless steel powders with the addition of carbides by high-energy mechanical milling is a novel method for recycling chips. With the increase in the consumption of raw material and energy and of the generation of residues, recycling is necessary due to environmental and industrial reasons. In this study, the effect of the addition of vanadium carbide on the morphology, particle size, and magnetic properties of the powders was investigated. The milling was realized using a planetary ball mill for 50 h at a milling speed of 350 rpm. The ball-to-powder weight ratio used was 20:1 and the 0, 1, and 3% wt. vanadium carbide addition. Produced duplex stainless steel powders from recycling chips were characterized by a scanning electron microscope (SEM), a laser particle size analyzer, X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and magnetic characterization. The milling process led to the formation of martensite induced by deformation phase. It was verified that the addition of 3% carbide was the most effective in reduction of the particle size when compared to milling without carbide. The particle size of fabricated powders after 50 h of milling with 3% vanadium carbide addition was about 174 times lower than that of initial chips. [ABSTRACT FROM AUTHOR]

A rapid method for fabrication of micro-channel on glass substrates is introduced and investigated in this paper. Wire-cut electro discharge machining (WEDM) and ultrasonic machining (USM) were used as manufacturing processes for machining the microtools and micro-channels, respectively. The copper micro-tool was machined using WEDM and the optimal design of the tool was achieved using Taguchi design of experiment. After overall evaluation criteria (OEC) analysis, the optimum conditions were achieved as Ton as 25 μs, Toff as 6 μs, Ip as 1 A, and Wf as 75 mm/s. Further, it was used for fabrication of micro-tools with different profiles such as square, circular, and zigzag. The fabricated micro-tools were used to machine serpentine micro-channels on glass using USM at various power ratings such as 40, 50, and 60%. After machining, net overcut of the micro-channels were found as 74.65, 75.86, and 81.75 μm for square, circular, and zigzag profiles, respectively. [ABSTRACT FROM AUTHOR]

Surface reflection existed in most optical elements that reduce the light transmission quality and bring down the optical system performance. Freeform optics is the key element in modern optics that it is strongly necessary to improve the anti-reflective performance. Therefore, the design and fabrication of anti-reflective freeform surfaces attract many researchers' attention, and this paper proposed a 3-DOF pseudo random turning method for the fabrication. The core idea is that three-processed random signal is coupled to freeform surface normal turning toolpath, and the new toolpath takes the diamond tool do micro-vibration in three directions in the turning process to break down the periodic tool mark residual structure. This method is implemented by a 3-DOF fast tool servo (FTS) system. The cutting results show that the new toolpath can disrupt the periodic turning residual structures which have the anti-reflective property, and higher hardness material is conductive to the formation of surfaces microstructure. Better anti-reflective surfaces can be obtained by optimizing tool geometric parameters and cutting parameters. [ABSTRACT FROM AUTHOR]

Fast tool servo (FTS) in ultra-precision machining (UPM) is an enabling and efficient technology for fabricating optical freeform surfaces or microstructures with submicrometric form accuracy and nanometric surface finish. There are many kinds of FTS in the different driving principle to present their various performances currently. Their kernel technologies influence the machining ability and accuracy of freeform surfaces, consequently receiving much research attention and interest. These technologies are generally summarized as the development of FTS structure, the advanced control algorithms, tool path planning, machining condition monitoring, and surface measurement and error compensation. This paper aims to survey the current state of the art in machining freeform optics by FTS. An analysis of the principle, performance, and application of FTS machining with regard to freeform optics is presented. And the key machining technologies for optical freeform surfaces by FTS are then introduced in detail. The challenges and opportunities for further studies are concluded according to the FTS machining difficult of optical freeform surfaces finally. [ABSTRACT FROM AUTHOR]

A conductive pattern is formed by a conductive material on the substrate having an electromagnetic function. Ink-jet printing using metal nanoparticles is an attractive method for the direct fabrication of a conductive pattern, with low-cost, low-waste, and simple process. The conductive pattern that is usually fabricated on complex surface substrates is widely used, but this method has several drawbacks like stacking of printing curves to the surface and complexity of the motion path; moreover, the conductive inks flow easily on the surface, resulting in low printing accuracy. In addition, each curve needs to be individually cured leading to a long interface, thus resulting into the decrease in conductivity. In this pursuit, the current work presents a reduced dimension patch printing method, which uses a series of patches to approach the surface. These patches were rotated to the horizontal plane through the five-axis motion system for printing and curing by turn, so that the surface printing gets converted to two-dimensional printing. To execute this method, we designed the print path planning algorithm as follows: initially, based on the topological relation of the triangles in the STL (stereolithography) model, the sub-region culling method was used to reduce the number of final patches and the length of the boundary, as well as to improve the conductivity. Subsequently, the patches were rotated to the horizontal plane for optimizing the print path, by turn according to the adjacent relation, thus achieving the ink-jet process in two-dimensional motion. This improved the efficiency and ensured that the conductive inks were always on the horizontal plane before curing, thus effectively avoiding its flow and improving the printing precision. Additionally, the patch was integrally cured to improve the overall connectivity. The results show that the algorithm could achieve the print path planning and significantly reduce the number of print patches and boundary length. [ABSTRACT FROM AUTHOR]