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A cost-effective stereolithography for medium-scale components is developed to fabricate 3D components with high build speed and resolution from photo-curable resin. The developed SLA utilizes a focused light beam of wavelength range (300 nm–700 nm) coming from the DLP projector and passes through the objective lens and finally imposed on the platform containing a layer of photo-curable resin. After focusing the light beam on the liquid resin layer, the photo-polymerization reaction occurs and the liquid resin becomes solid. Thus, the 3D object is fabricated layer by layer curing of liquid resin. The photopolymer used in this experimentation is polyethylene glycol di-acrylate and Irgacure 784 as photo-initiator. The Creo 3.0 software is used for modelling of 3D objects. A special MATLAB code is developed for slicing of the 3D model and displaying the sliced image one by one through DLP projector. The Arduino microcontroller with stepper motor and ball screw is used to control the motion of Z-stage platform. The Creation workshop software is also used to control motion of the Z-stage and period to display the sliced images through DLP projector. The medium-scale 3D objects with rectangular, square, and circular cross-sections are obtained by curing the aforementioned photo-curable resin. It is observed that the 3D objects are best cured for two seconds curing time with 0.1 mm curing depth along Z-axis.

Three-dimensional (3D) printing, also known as additive manufacturing, has the advantages of low cost, easy structure operation, rapid prototyping, and easy customization. In the past few years, materials with different structures, compositions, and properties have been widely studied as prospects in the field of 3D printing. This paper reviews the synthesis methods and morphologies of one-, two- and three-dimensional micro/nano materials and their composites, as well as their applications in electrochemistry, such as supercapacitors, batteries, and electrocatalysis. The latest progress and breakthroughs in the synthesis and application of different structural materials in 3D-printing materials, as well as the challenges and prospects of electrochemical applications, are discussed.

Electron Beam Melting (EBM) is a powder-bed additive manufacturing technology enabling the production of complex metallic parts with generally good mechanical properties. However, the performance of powder-bed based additively manufactured materials is governed by multiple factors that are difficult to control. Alloys that solidify in cubic crystal structures are usually affected by strong anisotropy due to the formation of columnar grains of preferred orientation. Moreover, processing induced defects and porosity detrimentally influence static and cyclic mechanical properties. The current study presents results on processing of a metastable austenitic CrMnNi steel by EBM. Due to multiple phase transformations induced by intrinsic heat-treatment in the layer-wise EBM process the material develops a fine-grained microstructure almost without a preferred crystallographic grain orientation. The deformation-induced phase transformation yields high damage tolerance and, thus, excellent mechanical properties less sensitive to process-induced inhomogeneities. Various scan strategies were applied to evaluate the width of an appropriate process window in terms of microstructure evolution, porosity and change of chemical composition.

Additive manufacturing (AM) is an advanced manufacturing process that provides the opportunity to build geometrically complex and highly individualized lightweight structures. Despite its many advantages, additively manufactured components suffer from poor surface quality. To locally improve the surface quality and homogenize the microstructure, friction stir processing (FSP) technique was applied on Al-Si12 components produced by selective laser melting (SLM) using two different working media. The effect of FSP on the microstructural evolution, mechanical properties, and corrosion resistance of SLM samples was investigated. Microstructural investigation showed a considerable grain refinement in the friction stirred area, which is due to the severe plastic deformation and dynamic recrystallization of the material in the stir zone. Micro-hardness measurements revealed that the micro-hardness values of samples treated using FSP are much lower compared to SLM components in the as-built condition. This reduction of hardness values in samples treated with FSP can be explained by the dissolution of the very fine Si-phase network, being characteristic for SLM samples, during FSP. Surface topography also demonstrated that the FSP results in the reduction of surface roughness and increases the homogeneity of the SLM microstructure. Decreased surface roughness and grain size refinement in combination with the dissolved Si-phase network of the FSP treated material result in considerable changes in corrosion behavior. This work addresses the corrosion properties of surface treated additive manufactured Al-Si12 by establishing adequate microstructure-property relationships. The corrosion behavior of SLM-manufactured Al-Si12 alloys is shown to be improved by FSP-modification of the surfaces.

Fused deposition modeling (FDM) is a widely applied rapid prototyping technology that produces layered models from specially designed thermoplastic filaments. Thermoplastic materials can be layered using several parameters that influence the mechanical properties of the printed object. In this study, the effects of freeze–thaw cycles on the physical characteristics of FDM objects printed using the ULTEM 9085 filament is assessed. The samples used in this study were printed with an air gap of –0.025 mm and at raster angles of 0°, 45°, and 90°. The results indicate that freeze–thaw conditioning reduces the tensile properties of FDM samples. Results also can help enhance FDM material properties to withstand significant temperature changes whilst having a prolonged service life.

Flexible printed electronic technology makes it possible to fabricate low-cost digital microfluidic (DMF) chips. Inkjet printing on flexible substrates is one of the most cost-effective fabrication processes for DMF chips. Based on inkjet printing technology and simplified coating methods of dielectric and hydrophobic layers, we fabricated low-cost flexible DMF chips (FDMFCs) on PET sheet and on matte photo paper. The surface quality, conductivity and spatial output resolution of the silver lines under different number of printings, different line widths and line gaps on the two types of FDMFCs were comprehensively analyzed. The traditional square dispensing electrodes were optimized to reduce the volume error of the droplets generated during the repeated dispensing operations. Droplets can be driven to implement all the operations on various configurations of FDMFCs by electrowetting-on-dielectric, including closed configuration, open configuration, hybrid configuration composed of closed and open regions on a single chip, and open curved configuration, which are defined as full-range droplet actuation. The droplet motion between closed and open regions in two position modes of the top plate was deeply studied. Droplet operation experiments prove that the motion performance of droplets can be comparable to that of chips processed by traditional technology, and the rapid prototyping technology of the FDMFCs can make the performance of droplet operation mainly depend on the conductivity of the electrode layer and the electrode gap and greatly weaken the influence of the substrate surface quality on the FDMFCs.

Additive Manufacturing (AM) is an appropriate name to describe the technologies that erect 3D objects by enumerating layer-upon-layer of material, hence the name additive, whether the material is thermoplastic, metal, concrete, exclusive materials such as ceramics, carbon fibre or even human tissues. A 3D Slicing programme (to slice the 3D model into successive layers), machine equipment configuration, and material layering are all popular AM technologies. The Slicing programme decodes data from the CAD file, slices it into successive layers, and converts it to G-codes after it is created. When we run this G-code in the AM System, the computer builds a 3D component by layering liquid resin, powder, or solid filaments on top of each other. Rapid prototyping (RP) is one of the quickest-growing automated manufacturing innovations, with the ability to go from CAD models to finished products. Powder Bed Fusion (PBF) and Direct Energy Deposition (DED) are two kinds of metal additive manufacturing techniques. The metal additive manufacturing method can also be classified by material type, energy source, build scale, and so on. This paper discusses the relevance of metal additive manufacturing and provides detailed information on the processes of Selective Laser Melting, Selective Laser Sintering, Direct Metal Deposition, and Laser Metal Deposition.

In the Rapid Prototyping process, surface finish is very critical as it affects the part quality. As Rapid Prototyping is moving towards Rapid manufacturing there is an increasing stress on obtaining good quality parts. Surface finish of Rapid Prototyping parts is becoming more and more important with more parts being used for end purposes. Good surface finish is required for better functionality and look, but also for cost reduction in terms of reducing post-processing expenditure. A critical study and analysis of process parameters behaviour has been carried out for assessing the surface quality of parts manufactured on Selective Laser Sintering Rapid Prototyping system. The principal concern of experimental work has been investigated for achieving better surface finish by which the life of parts is governed. The primary objective of study is to analyze the optimum process parameters of Selective Laser Sintering Rapid Prototyping system. The material selected for study is “Dura Form“ and experimental work was carried out on selective laser sintering rapid prototyping machine DTM Vanguard 2500. Taguchi method is used to investigate the parameters and results are improved by using signal-to-noise methods. The major process parameters selected for study were Part Orientation, Laser Power and Scan Spacing. The study and analysis depict that Part Orientation has a major effect on the surface roughness of the part produced on Rapid Prototyping Machine. It has been observed from the study that lower value of Part Orientation level I (0 degree) gives better finish and this is because of less number of layers required for manufacturing of part. It has been observed from the study of second process parameter i.e. Laser Power that the surface finish was better at 16 W. Similarly, the surface finish obtained at lower values of Scan Spacing was for better as compared to higher values of Scan Spacing. The comparative analysis of three-process parameter indicates that the effects of variation of Part Orientation and Scan Spacing parameters are more as compare to Laser Power.

Selective laser sintering (SLS) is an additive manufacturing technology whereby parts are built through selective consolidation of a powder by a laser beam. Recently, Polypropylene (PP) has been used in the SLS because of its appropriate mechanical performance as well as low cost and density. In the SLS, laser parameters are very effective on the mechanical properties of the sintered parts. In this study, the effects of the laser parameters including power, the laser scanning speed, and the laser scanning pattern on the tensile strength of the sintered samples were experimentally investigated. The PP and PP/CNT (carbon nanotube) composites were used as raw materials and the results were compared. Taguchi method was employed as the experimental design, and optimal levels of parameters were extracted using signal-to-noise analysis. The main effects of factors and interactions were considered in this paper. The results show that the laser scanning pattern and the laser power have the most effects on the tensile strength of the produced samples. In addition, the comparison between the results of the experiments demonstrates an increase in the tensile strength, which is 15% in maximum value, by adding CNT to PP.

The application of stereolithography, gives the possibilities to manufacture components with complex shape, during one continuous process based on the prepared virtual model in CAD system. The paper presents the results of experimental tests for samples printed using Low Force Stereolithography (LFS)TM technique, using Rigid 4000 Resin, Formlabs company. The experimental studies used unconventional post-processing, which consists in extending the exposure to UV lamps, without the application of heating. In the next step, optimized post processing parameters were used to manufacture components with different types and degrees of filling - linear and hexagonal. In the experiment, the samples were testes to a tensile strength test and a three-point bending test. The goal of the experiment was to select optimal parameters for post-processing and element design to reduce the component weight.

Additive manufacturing (AM) has created a new era of digital manufacturing, where engineering practices, computer-aided design platforms, and part sourcing pipelines are dramatically changing. AM techniques are capable of producing plastic, metal, and ceramic components for both prototyping and end-use purposes. In this review, the fabrication of dense, structural advanced ceramic components using the seven families of additive manufacturing is discussed through a historical perspective. Initial studies on additive manufacturing of ceramic materials were reported just a few years after those of metal and plastic materials. However, industrial application of ceramic additive manufacturing is more than a decade behind metallic and plastic materials. Many of the challenges of ceramic AM can be traced back to the intrinsic difficulties of processing structural ceramic materials, including high processing temperatures, defect-sensitive mechanical properties, and poor machining characteristics. To mature the field of ceramic AM, future research and development should focus on expanding material selection, improving printing and post-processing control, realizing single-step processing, and unique capabilities such as multi-material and hybrid processing.

Fused filament fabrication (FFF), also known as fused deposition modeling (FDM™), is considered one of the most promising additive manufacturing (AM) methods for its versatility, reliability and affordability. First adopted by industries for professional uses such as rapid prototyping, then by the general public in recent years, FFF has gathered itself considerable attention. Nevertheless, despite key advancements in printer technologies and filament materials, the fabrication of robust, performing and functional parts for high-demanding practical applications remains a significant challenge. Due to intrinsic deficiencies, such as the presence of voids and weak layer-to-layer adhesion, FFF-printed parts are plagued by weak and anisotropic mechanical properties in contrast to their conventionally manufactured counterparts. With the increasing demand for designable porous structures in the fields of biomedicine, 4D printing and lightweight cellular composites, understanding the challenges presented by void presence has become more relevant than ever. As existing literature has reviewed the significance of interlayer bonding, this review focuses on documenting recent insights on the formation of voids by its categorization, research method and mechanism. The primary objective is to provide a comprehensive understanding of the two current primary methods of void research—quantitative analysis and imaging. Detailed discussions on the effects of feedstock and printing parameters on void formation are also presented. Lastly, this review discusses gaps in the current research and outlines unaddressed challenges regarding void formation and its relation with the mechanical performance of FFF parts.

Purpose In flexible electronics applications, organic inks are mostly used for inkjet printing. Three-dimensional (3 D) printing technology has the advantages of low cost, high speed and good precision in modern electronic printing. The purpose of this study is to solve the high cost of traditional printing and the pollution emissions of organic ink. It is necessary to develop a water-based conductive ink that is easily degradable and can be 3 D printed. A nano-silver ink printed circuit pattern with high precision, high conductivity and good mechanical properties is a promising strategy. Design/methodology/approach The researched nano-silver conductive ink is mainly composed of silver nanoparticles and resin. The effect of adding methyl cellulose on the ink was also explored. A simple 3 D circuit pattern was printed on photographic paper. The line width, line length, line thickness and conductivity of the printed circuit were tested. The influence of sintering temperature and sintering time on pattern resistivity was studied. The relationship between circuit pattern bending performance and electrical conductivity is analyzed. Findings The experimental results show that the ink has the characteristics of low silver content and good environmental protection effect. The printing feasibility of 3 D printing circuit patterns on paper substrates was confirmed. The best printing temperature is 160°C–180°C, and the best sintering time is 30 min. The circuit pattern can be folded 120°, and the cycle is folded more than 60 times. The minimum resistivity of the circuit pattern is 6.07 µΩ·cm. Methyl cellulose can control the viscosity of the ink. The mechanical properties of the pattern have been improved. The printing method of 3 D printing can significantly reduce the sintering time and temperature of the conductive ink. These findings may provide innovation for the flexible electronics industry and pave the way for alternatives to cost-effective solutions. Originality/value In this study, direct ink writing technology was used to print circuit patterns on paper substrates. This process is simple and convenient and can control the thickness of the ink layer. The ink material is nonpolluting to the environment. Nano-silver ink has suitable viscosity and pH value. It can meet the requirements of pneumatic 3 D printers. The method has the characteristics of simple process, fast forming, low cost and high environmental friendliness.

Additive manufacturing (AM) especially laser additive manufacturing (LAM), a novel manufacturing technique of layer-by-layer forming according to geometric model, provides a decent option for materials processing. It owns advantages of rapid prototyping, customization, high material utilization, and the ability to form complicated structures. This paper reviews popular LAM techniques of selective laser sintering/melting, laser metal deposition and laser direct writing. The development status of metallic materials including pure metal, steel, superalloy, titanium and aluminum alloy is presented. The challenges and application limitations of LAM are involved and the development trend in the future is forecasted. In summary, this paper gives an overview of metal LAM expecting to made helpful suggestions on future research and development.

Purpose The purpose of this paper is to establish a methodology for the design and development of patient-specific elbow implant with an elastic modulus close to that of the human bone. One of the most preferred implant material is titanium alloy which is about 8 to 9 times higher in strength than that of the human bone and is the closest than other metallic biomedical materials. Design/methodology/approach The methodology begins with the design of the implant from patient-specific computed tomography information and incorporates the manufacturing of the implant via a novel rapid prototyping assisted microwave sintering process. Findings The elastic modulus and the flexural strength of the implant were observed to be comparable to that of human elbow bones. The fatigue test depicts that the implant survives the one million cycles under physiological loading conditions. Other mechanical properties such as impact energy absorption, hardness and life cycle tests were also evaluated. The implant surface promotes human cell growth and adhesion and does not cause any adverse or undesired effects i.e. no cytotoxicity. Practical implications Stress shielding, and therefore, aseptic loosening of the implant shall be avoided. In the event of any trauma post-implantation, the implant would not hurt the patient. Originality/value The present study describes a methodology for the first time to be able to obtain the strength required for the medical implant without sacrificing the fatigue life requirement.

Purpose Rapid prototyping (RP) technology is widely used in many fields in recent years. Bone tissue engineering (TE) is an interdisciplinary field involving life sciences, engineering and materials science. Hydroxyapatite (HAp) are similar to natural bone and it has been extensively studied due to its excellent biocompatibility and osteoconductivity. This paper aims to review nanoscaled HAp-based scaffolds with high porosity fabricated by various RP methods for bone regeneration. Design/methodology/approach The review focused on the fabrication methods of HAp composite scaffolds through RP techniques. The paper summarized the evaluation of these scaffolds on the basis of their biocompatibility and biodegradability through in vitro and in vivo tests. Finally, a summary and perspectives on this active area of research are provided. Findings HAp composite scaffold fabricated by RP methods has been widely used in bone TE and it has been deeply studied by researchers during the past two decades. However, its brittleness and difficulty in processing have largely limited its wide application in TE. Therefore, the formability of HAp combined with biocompatible organic materials and fabrication techniques could be effectively enhanced, and it can be used in bone TE applications finally. Originality/value This review paper presented a comprehensive study of the various types of HAp composite scaffold fabricated by RP technologies and introduced their potential application in bone TE, as well as future roadmap and perspective.

Cold isostatic pressing, gelcasting, and protein coagulation are the main methods to produce machinable green bodies of ceramics. They generally employ multiple additives, such as binders, dispersa...

High-entropy alloys (HEA) are of high current interest due to their unique and attractive combination of structural, physical, chemical or magnetic properties. HEA comprise multiple principal elements, unlike conventional alloys. The composition space of HEA is enormous and only a minuscule fraction has been studied. Magnetic HEA are a promising alternative to conventional soft magnetic metallic materials, which typically exhibit poor mechanical properties. We review the progress in the development of magnetic HEA. The influence of alloy composition, crystal structure, phase fraction and processing parameters on the magnetic properties are discussed. Magnetic HEA processed by advanced experimental high throughput techniques such as additive manufacturing, co-sputtering, diffusion multiples, rapid prototyping, and designed via combinatorial computational techniques, such as thermodynamic and phase diagram calculations, density functional theory, machine learning etc. are reviewed. Conventional processing techniques are also discussed. Future trends in magnetic HEA are outlined.

Rapid prototyping methods for the design and fabrication of polymeric labs-on-a-chip are on the rise, as they allow high degrees of precision and flexibility. For example, a microfluidic platform may require an optimization phase in which it could be necessary to continuously modify the architecture and geometry; however, this is only possible if easy, controllable fabrication methods and low-cost materials are available. In this paper, we describe the realization process of a microfluidic tool, from the computer-aided design (CAD) to the proof-of-concept application as a capture device for circulating tumor cells (CTCs). The entire platform was realized in polymethyl methacrylate (PMMA), combining femtosecond (fs) laser and micromilling fabrication technologies. The multilayer device was assembled through a facile and low-cost solvent-assisted method. A serpentine microchannel was then directly biofunctionalized by immobilizing capture probes able to distinguish cancer from non-cancer cells without labeling. The low material costs, customizable methods, and biological application of the realized platform make it a suitable model for industrial exploitation and applications at the point of care.

In recent years, interest in microneedle devices for drug and vaccine delivery and point-of-care diagnostics has grown due to low cost, convenience and minimal invasiveness. A cluster of miniature needles on a small patch could enhance the quality of human health care, revolutionizing test and drug and vaccine delivery systems. However, current fabrication methods are not viable for cost-effective large-scale manufacture. This study reports fabrication of ultra-sharp microneedles with microfluidic channels using two-photon polymerization (2PP) which enables flexible designs with resolution down to 100 nm. The technique is ideally suited to prototyping and the fabrication of master molds from which elastomeric negative-molds have been used in a rapid micromolding technique to make batches of ultra-sharp microneedles. This micromolding process has mass manufacturing potential.

Purpose This study aims to develop and demonstrate a deposition framework for the implementation of a region-based adaptive slicing strategy for the Tungsten Inert Gas (TIG) welding-based additive manufacturing system. The present study demonstrates a deposition framework for implementing a novel region-based adaptive slicing strategy termed as Fast Interior and Accurate Exterior with Constant Layer Height (FIAECLH). Design/methodology/approach The mentioned framework has been developed by performing experiments using the design of experiments and analyzing the experimental data. Analysis results have been used to obtain the mathematical function to integrate customization in the process. The paper, in the end, demonstrates the FIAECLH framework for implementing region-based adaptive slicing strategy on the hardware level. Findings The study showcase a new way of implementing the region-based adaptive slicing strategy to arc-based metal additive manufacturing. The study articulating a new strategy for its implementation in all types of wire and arc additive manufacturing processes. Originality/value Wire-arc-based technology has the potential to deliver cost-effective solutions for metal additive manufacturing. The research on arc welding-based processes is being carried out in different dimensions. To deposit parts with complex geometry and better dimensional accuracy implementation of a novel region-based adaptive slicing strategy for the arc-based additive manufacturing process is an essential task. The successful implementation of an adaptive slicing strategy would ease the fabrication of complex geometry in less time. This paper accomplishes this need of implementing a region-based adaptive slicing strategy as no experimental investigation has been reported for the TIG-based additive manufacturing process.

A prevalent method for rapid prototyping of metallic parts is gas metal arc welding (GMAW). As the input parameters impose a highly nonlinear impact on the weld bead geometry, precise estimation of the geometry is a complex problem. Therefore, in this study, a novel combination of the most powerful machine learning algorithms is selected to overcome the complexity of the problem and also reach an acceptable degree of precision. To this end, the hybrid combination of the support vector machine (SVM) and relevance vector machine (RVM) is developed based on the random forest (RF) ensemble learning approach. The models are established based on a global database of welding geometry, and the corresponding process parameters obtained are based on a set of experiments. Performance evaluation between RVM, SVM, and the proposed model was performed based on the coefficient of determination ([Formula: see text]) and the ratio of root means square error (RMSE) to the maximum measured outputs ([Formula: see text]/[Formula: see text]). The RF-based RVM-SVM model obtained 0.9725 and 0.8850 for [Formula: see text] and 0.0257 and 0.0447 for [Formula: see text]/[Formula: see text] in predicting the height and width of the bead, respectively. The result clearly showed the effectiveness of the proposed model in predicting the GMAW trend.

Purpose Fused deposition modeling (FDM) is one of the most adopted additive manufacturing techniques to produce prototypes and/or final parts regardless of geometrical complexity restrictions. One of the most challenging aspects of this technology is the attainable roughness. The purpose of this study is to evaluate the capability of the slurry impacts to improve the surface roughness of parts fabricated using FDM. Moreover, a regression model for predicting the values of surface roughness was developed. Design/methodology/approach The developed technique imposes a silica–water mixture which softens the staircase on the surface and leaves it smoother. The process introduces three main factors: building orientation; layer thickness; and impact angle of the slurry particles. Experimentally, a test rig was used to evaluate the effect of these factors on surface roughness. Statistically, Analysis of variance (ANOVA) and regression analysis were conducted to study the contribution of the individual factors on the roughness. Findings The results reveal that the effect of slurry impacts has a good impact on surface roughness, and the three factors have significant effect on surface roughness. Originality/value This paper contributes to new knowledge by providing a new technique for enhancing the surface roughness of FDMed products. ANOVA and regression analysis is a useful tool to parametrically study the surface roughness in terms of building and testing factors.

Fused Deposition Modeling (FDM) is a rapid prototyping method, widely used in the manufacture of plastic parts with complex geometric shapes. The quality of the parts manufactured by this process depends on the plastic material used and the FDM parameters. In this context, this paper will present the results of a theoretical and experimental research on how FDM parameters influence the tensile strength and hardness of samples made of PLA (Polylactic Acid).

Graphical abstract Three-dimensional (3-D) printing, also known as additive manufacturing, refers to a method used to generate a physical object by joining materials in a layer-by-layer process from a three-dimensional virtual model. 3-D printing technology has been traditionally employed in rapid prototyping, engineering, and industrial design. More recently, new applications continue to emerge; this is because of its exceptional advantage and flexibility over the traditional manufacturing process. Unlike other conventional manufacturing methods, which are fundamentally subtractive, 3-D printing is additive and, therefore, produces less waste. This review comprehensively summarises the application of additive manufacturing technologies in chemistry, chemical synthesis, and catalysis with particular attention to the production of general laboratory hardware, analytical facilities, reaction devices, and catalytically active substances. It also focuses on new and upcoming applications such as digital chemical synthesis, automation, and robotics in a synthetic environment. While discussing the contribution of this research area in the last decade, the current, future, and economic opportunities of additive manufacturing in chemical research and material development were fully covered.

Traditional soft lithography based PDMS device fabrication requires complex procedures carried out in a clean room. Herein, we report a photolithography-free method that rapidly produces PDMS devices in 30 min. By using a laser cutter to ablate a tape, a male photoresist mold can be obtained within 5 min by a simple heating-step, which offers significant superiority over currently used photolithography-based method. Since it requires minimal energy to cut the tape, our fabrication strategy shows good resolution (∼ 100 µm) and high throughput. Furthermore, the micro-mold height can be easily controlled by changing the tape types and layers. As a proof-of-concept, we demonstrated that the fabricated PDMS devices are compatible with biochemical reactions such as quenching reaction of KI to fluorescein and cell culture/staining. Collectively, our strategy shows advantages of low input, simple operation procedure and short fabrication time, therefore we believe this photolithography-free method could serve as a promising way for rapid prototyping of PDMS devices and be widely used in general biochemical laboratories.

Biomimetic actuators with stimuli-responsiveness, adaptivity, and designability have attracted extensive attention. Recently, soft intelligent actuators based on stimuli-responsive materials have been gradually developed, but it is still challenging to achieve various shape manipulations of actuators through a simple 3D printing technology. In this paper, a 3D printing strategy based on magneto-active materials is developed to manufacture various biomimetic magnetic actuators, in which the new printable magnetic filament is composed of a thermoplastic rubber material and magnetic particles. The continuous shape transformation of magnetic actuators is further demonstrated to imitate the motion characteristic of creatures, including the predation behavior of octopus tentacles, the flying behavior of the butterfly, and the flower blooming behavior of the plant. Furthermore, the magnetic field-induced deformation of the biomimetic structure can be simulated by the finite element method, which can further guide the structural design of the actuators. This work proves that the biomimetic actuator based on soft magneto-active materials has the advantages of programmable integrated structure, rapid prototyping, remote noncontact actuation, and rapid magnetic response. As a result, this 3D printing method possesses broad application prospects in soft robotics and other fields.

Rapid prototyping is closely related to 3D printers (additive manufacturing). Rapid prototyping is a technique for making a prototype model from a CAD file which is the final result, while a 3D printer is one of the processes. The 3D printer process is by melting the filament layer by layer to form a component or product. The 3D printer melting process uses a heater on the nozzle. This study aims to analyze the effect of nozzle diameter and layer thickness on the accuracy (dimensional measurement) of 3D printer objects. To determine the precision, a test object was made based on ASTM D995-08. The variation of nozzle diameter used is 0.2 mm and 0.5 mm, while the variation in layer thickness is 0.1 mm and 0.3 mm. In this study, delta type 3D printing was used with polylactic acid (PLA) material to make test objects. Dimension measurement using ASTM D5947-06. Analysis of the measurement results used ANOVA with a 2-level factorial design type and a 2 factorial interaction (2FI) model design using Design-Expert®. software. From the actual measurement results, the most accurate (precise) results are obtained on the test object with a variation of the nozzle parameters with a diameter of 0.2 mm and a layer thickness of 0.1 mm. From the analysis of the specimen measurement data, it can be concluded that the nozzle diameter significantly affects the response of length, width and height while the thickness of the layer affects the response of the length and width of the specimen.

3D printers using fused filament fabrication (FFF) with thermoplastic filaments have been employed for rapid prototyping applications. The present research focuses on 3D-printed short carbon fiber/...

Purpose This study aims to describe the preparation of antimicrobial material usable in 3D printing of medical devices. Despite the wealth of technological progress at the time of the crisis caused by SARS-CoV-2 virus: Virus that causes current Pandemic situation (COVID-19), the global population had long been exposed beforehand to an acute absence of essential medical devices. As a response, a new type of composite materials intended for rapid prototyping, based on layered silicate saponite (Sap), antimicrobial dye phloxine B (PhB) and thermoplastics, has been recently developed. Design/methodology/approach Sap was modified with a cationic surfactant and subsequently functionalized with PhB. The hybrid material in powder form was then grounded with polyethylene terephthalate-glycol (PETG) or polylactic acid (PLA) in a precisely defined weight ratio and extruded into printing filaments. The stability and level of cytotoxicity of these materials in various physiological environments simulating the human body have been studied. The applicability of these materials in bacteria and a yeast-infected environment was evaluated. Findings Ideal content of the hybrid material, with respect to thermoplastic, was 15 weight %. Optimal printing temperature and speed, with respect to maintaining antimicrobial activity of the prepared materials, were T = 215°C at 50 mm/s for PETG/SapPhB and T = 230°C at 40 mm/s for PLA/SapPhB. 3 D-printed air filters made of these materials could keep inner air flow at 63.5% and 76.8% of the original value for the PLA/SapPhB and PETG/SapPhB, respectively, whereas the same components made without PhB had a 100% reduction of airflow. Practical implications The designed materials can be used for rapid prototyping of medical devices. Originality/value The new materials have been immediately used in the construction of an emergency lung ventilator, Q-vent, which has been used in different countries during the COVID-19 crisis.

Nowadays, rapid prototyping is an emerging trend that is followed by industries and auto sector on a large scale which produces intricate geometrical shapes for industrial applications. The wire arc additive manufacturing (WAAM) technique produces large scale industrial products which having intricate geometrical shapes, which is fabricated by layer by layer metal deposition. In this paper, the CMT technique is used to fabricate single-walled WAAM samples. CMT has a high deposition rate, lower thermal heat input and high cladding efficiency characteristics. Humping is a common defect encountered in the WAAM method which not only deteriorates the bead geometry/weld aesthetics but also limits the positional capability in the process. Humping defect also plays a vital role in the reduction of hardness and tensile strength of the fabricated WAAM sample. The humping defect can be controlled by using low heat input parameters which ultimately improves the mechanical properties of WAAM samples. Two types of path planning directions namely uni-directional and bi-directional are adopted in this paper. Results show that the optimum WAAM sample can be achieved by adopting a bi-directional strategy and operating with lower heat input process parameters. This avoids both material wastage and humping defect of the fabricated samples.

Hot Melt Extrusion (HME) is a continuous pharmaceutical manufacturing process that has been extensively investigated for solubility improvement and taste masking of active pharmaceutical ingredients. Recently, it is being explored for its application in 3D printing. 3D printing of pharmaceuticals allows flexibility of dosage form design, customization of dosage form for personalized therapy and the possibility of complex designs with the inclusion of multiple actives in a single unit dosage form. Fused Deposition Modeling (FDM) is a 3D printing technique with a variety of applications in pharmaceutical dosage form development. FDM process requires a polymer filament as the starting material that can be obtained by hot melt extrusion. Recent reports suggest enormous applications of a combination of hot melt extrusion and FDM technology in 3D printing of pharmaceuticals and need to be investigated further. This review in detail describes the HME process, along with its application in 3D printing. The review also summarizes the published reports on the application of HME coupled with 3D printing technology in drug delivery.

Interdigital electrochemical energy storage (EES) device features small size, high integration, and efficient ion transport, which is an ideal candidate for powering integrated microelectronic systems. However, traditional manufacturing techniques have limited capability in fabricating the microdevices with complex microstructure. Three-dimensional (3D) printing, as an emerging advanced manufacturing technology in rapid prototyping of 3D microstructures, can fabricate interdigital EES devices with highly controllable structure. The integration of 3D printing and interdigital devices provides great advantages in electrochemical energy storage. In this review, we discuss the common 3D printing techniques for interdigital EES devices fabrication, then the corresponding material requirements are also introduced. Recent significant research progress made in 3D-printed interdigital electrodes of batteries and supercapacitors are highlighted. Finally, to facilitate further development of 3D-printed interdigital EES devices, relevant challenges are summarized and some prospects are also proposed.

Additive manufacturing has evolved from a rapid prototyping tool to a set of manufacturing processes for functional parts. One of their most outstanding features is the ability to build complex geometry parts. However, their industrial application is limited because these parts exhibit heterogeneous and porous micro/mesostructures with anisotropic behavior. These structural characteristics, mainly porosity, are strongly related to the building parameters. In this work, a computational multiscale homogenization approach was implemented to determine the mechanical properties of unidirectional and criss-cross mesostructures generated by a material extrusion process (MEP). Representative volume elements (RVE) for simplified and real-like pore geometries were created to model the mesostructures and to perform the multiscale analysis. Stiffness tensor for each RVE was obtained and graphically represented to observe the mechanical properties as a function of the orientation. A great influence of the pore geometry on mechanical properties was observed. Finally, by comparing with experimental data, the results obtained were validated.

Polyaryletherketones (PAEK) have been hitherto the most promising high-performance semicrystalline thermoplastic polymers (HPPs) for several biomedical applications. These polymers make a competent replacement to implantable metals due to their biocompatibility, osteointegration properties, substantial bond strength, pliability, radiolucency and a comparable bone-like flexural modulus. Lately, additive manufacturing (AM) of customized 3D-printed patient-specific implants (PSI) using rapid prototyping techniques has been used for several surgical and medical implantations. Also, rapid technological progresses viz., fused deposition modelling and selective laser sintering in consort with enhanced imaging know-hows have streamlined the critical glitches of conventional HPPs processability with directing them to manufacture medically proficient 3D-PSI. Thus, PAEK and its polymers could not only be tailored into end-use implantable medical devices but also fit into newer AM technology-mediated biomedical arenas for other unexplored HPPs. This review summarizes the till date research on 3D-printed PAEK implant technology and its potential possibilities for their modernization and expansion in diverse musculoskeletal and soft tissue applications.

Aluminum alloy lattice structures featuring superior energy absorption, lightweight, and high strength-weight ratio, are achievable using Additive Manufacturing (AM) technology such as selective laser sintering. However, the size of the structure is limited, and the cost is relatively high. As a free-form rapid prototyping technology, Wire Arc Additive Manufacturing (WAAM) using electric arc as an energy source has the potential to fabricate medium to large-scale lattice structures with low cost and high process efficiency. This paper presents a strut-based process planning method for the WAAM system to fabricate large-sized lattice structures (strut-based wire structures) from the input models to the final parts. The proposed method includes the strut extraction module, strut bead modelling module, sequence initialization module, and sequence optimization module. Among these modules, bead modelling provides the essential database for process control, and an innovative sequence optimization module fulfills the automated process planning requirements without collision. A user-friendly interface has been developed for non-experts to operate the process planning. Finally, two- and three-dimensional lattice structures have been fabricated automatically using CAD models as inputs. These exercises demonstrate that the proposed strut-based process planning method contributes to producing practical lattice structures and highly automated WAAM system for industrial application.

Additive manufacturing (AM) or 3D printing is beginning to mature from a rapid prototyping to an industrial production technology. However, there are still a lot of fundamental questions that must be addressed in order to make this leap forward. There are many different AM technologies; here, we focus on laser powder bed fusion (LPBF). A key step in LPBF is the initial spreading of the powder layer before it is melted in a solid object, via interaction with a laser. Ideally the powder should be spread as a dense, uniform layer. However, developing a spreading process that can produce a consistent layer, across the wide range of powders used, is a challenge for LPBF manufactures. Therefore, we investigate the influence of materials and process parameters on layer quality. To perform this study we perform computing simulations using the discrete particle method (DPM), a.k.a. discrete element method. This allows us to define metrics to evaluate the powder layer quality, allowing direct comparisons of different tools and parameters. We emulated the effect of the complex particle shape and surface roughness via rolling resistance and interparticle sliding friction. Additionally we investigated the effect of particle cohesion and type of spreading tool. We found that all these factors have a major, albeit sometimes surprising influence on the powder layer quality. In particular, more irregular shaped particles, rougher particle surfaces and/or higher interfacial cohesion usually, but not always, lead to worse spreadability. In general, there is a trade-off between material and process parameters. For example, increasing the spreading speed decreases layer quality for non- and weakly cohesive powders, but improves it for strongly cohesive ones. On the other hand, using a counter-clockwise rotating roller as a spreading tool improves the powder layer quality compared to spreading with a blade. For both tools, a unique correlation between the quality criteria uniformity and mass fraction is reported allowing an easily measured experimental value to be related to the layer quality. Finally, we showed that size-segregation occurs during spreading and this effects is able to explain some of our results.

In this work, we printed a Nafion precursor membrane by fused deposition modeling (FDM) rapid prototyping technology and further fabricated IPMCs by electroless plating. The ion-exchange capacity of the Nafion membrane was tested, and the morphology of IPMCs was observed. The electro-mechanical properties of IPMCs under AC voltage inputs were studied, and grasping experiments were performed. The results show that the Nafion membrane after hydrolysis has a good ion-exchange ability and water-holding capacity. SEM observed that the thickness of the IPMC’s electrode layer was about 400 nm, and the platinum layer was tightly combined with the substrate membrane. When using a square wave input of 3.5 V and 0.1 Hz, the maximum current of IPMCs reached 0.30 A, and the displacement and blocking force were 7.57 mm and 10.5 mN, respectively. The new fabrication process ensures the good driving performance of the printed IPMC. And two pieces of IPMCs can capture the irregular objects successfully, indicating the feasibility of printing IPMCs by FDM technology. This paper provides a new and simple method for the fabrication of three-dimensional IPMCs, which can be further applied in flexible grippers and soft robotics.

Three-dimensional printing (3D-printing) is an asset for rapid prototyping. Therefore, this technology is applied in amateur, fundamental as well as in applied research communities. Moreover, the fused deposition modeling even allows a cheap and fast 3D-printing of functional filaments such as conductive or ferro-magnetic materials. Further applicable materials enable the production of electronic circuits, electrodes or even complete analytical sensors. Here, a 3D-printed stand-alone drift tube ion mobility spectrometer (IMS) completely manufactured in one process is presented. The ionization chamber, the Bradbury-Nielsen gate, the partly conductive drift tube, and the detector including an aperture grid and a Faraday plate were printed by dual extrusion 3D-printing. Therefore, non-conductive polylactic acid (PLA) was utilized for the housing and conductive PLA was used for the electrodes, the ion gate and the detector. Due to a magnetic quick lock system and a modular design, each part of this innovative ion mobility spectrometer can be exchanged in an instant. All parts were validated individually and as a whole by comparing them to an ion mobility spectrometer produced by computerized numerical control machining consisting of polytetrafluoroethylene (PTFE). To investigate the performance, parameters regarding the resolution, resolving power, signal-to-noise ratio, running-in period and long-term stability were used involving a set of isomeric volatile organic compounds (VOCs). Notably, every single 3D-printed component as well as the completely 3D-printed IMS could keep up with the traditionally produced ones. Furthermore, the signal intensity was comparable to the signal intensity of the PTFE-IMS in exemplary optimization steps. The resolution, resolving power and signal-to-noise ratio could be improved by the variation of the Bradbury-Nielsen gate design, thus demonstrating the potential of the 3D-printing for design optimization and rapid prototyping of analytical instrumentation.