Search results

This study aims to discuss the state-of-the-art digital factory (DF) development combining digital twins (DTs), sensing devices, laser additive manufacturing (LAM) and subtractive manufacturing (SM) processes. The current shortcomings and outlook of the DF also have been highlighted. A DF is a state-of-the-art manufacturing facility that uses innovative technologies, including automation, artificial intelligence (AI), the Internet of Things, additive manufacturing (AM), SM, hybrid manufacturing (HM), sensors for real-time feedback and control, and a DT, to streamline and improve manufacturing operations.

This study presents a novel perspective on DF development using laser-based AM, SM, sensors and DTs. Recent developments in laser-based AM, SM, sensors and DTs have been compiled. This study has been developed using systematic reviews and meta-analyses (PRISMA) guidelines, discussing literature on the DTs for laser-based AM, particularly laser powder bed fusion and direct energy deposition, in-situ monitoring and control equipment, SM and HM. The principal goal of this study is to highlight the aspects of DF and its development using existing techniques.

A comprehensive literature review finds a substantial lack of complete techniques that incorporate cyber-physical systems, advanced data analytics, AI, standardized interoperability, human–machine cooperation and scalable adaptability. The suggested DF effectively fills this void by integrating cyber-physical system components, including DT, AM, SM and sensors into the manufacturing process. Using sophisticated data analytics and AI algorithms, the DF facilitates real-time data analysis, predictive maintenance, quality control and optimal resource allocation. In addition, the suggested DF ensures interoperability between diverse devices and systems by emphasizing standardized communication protocols and interfaces. The modular and adaptable architecture of the DF enables scalability and adaptation, allowing for rapid reaction to market conditions.

Based on the need of DF, this review presents a comprehensive approach to DF development using DTs, sensing devices, LAM and SM processes and provides current progress in this domain.

Multi-jet deposition of the materials is a matured technology used for graphic printing and 3 D printing for a wide range of materials. The multi-jet technology is fine-tuned for liquids with a specific range of viscosity and surface tension. However, the use of multi-jet for low viscosity fluids like water is not very popular. This paper aims to demonstrate the technique, particularly for the water-ice 3 D printing. 3 D printed ice parts can be used as patterns for investment casting, templates for microfluidic channel fabrication, support material for polymer 3 D printing, etc.

Multi-jet ice 3 D printing is a novel technique for producing ice parts by selective deposition and freezing water layers. The paper confers the design, embodiment and integration of various subsystems of multi-jet ice 3 D printer. The outcomes of the machine trials are reported as case studies with elaborate details.

The prismatic geometries are realized by ice 3 D printing. The accuracy of 0.1 mm is found in the build direction. The part height tends to increase due to volumetric expansion during the phase change.

The present paper gives a novel architecture of the ice 3 D printer that produces the ice parts with good accuracy. The potential applications of the process are deliberated in this paper.

The aerospace, energy and automotive industries have seen wide use of composite materials because of their excellent mechanical properties, along with the benefit of weight reduction savings. As such, the purpose of this study is to provide an understanding of the mechanical performance of these materials under extreme operational conditions characteristic of in-service environments.

This study is novel in that it has evaluated the tensile performance and fracture response of additively manufactured continuous carbon fiber embedded in an onyx matrix (i.e. nylon with chopped carbon fiber) at cryogenic and room temperatures, for specimens manufactured with an angle between the specimen lying plane and the working build plane of 0°, 45° and 90°.

Research findings reveal enhanced tensile properties (i.e. ultimate tensile strength and modulus of elasticity) by the 0° (X) built specimens, as compared with the 45° (XZ45) and 90° (Z) built specimens at cryogenic temperature. A reduction in ductility is observed at cryogenic temperature for all build orientations. Fractographic analysis reveals the presence of fiber pullout/elongation, pores within the onyx matrix and chopped carbon fiber near fracture zone of the onyx matrix.

Research findings present tensile properties (i.e. ultimate tensile strength, modulus of elasticity and elongation%) for three-dimensional (3D)-printed onyx with and without reinforcing continuous carbon fiber composites at cryogenic and room temperatures. Reinforcement of continuous carbon fibers and reduction to cryogenic temperatures appears to result, in general, in an increase in the tensile strength and modulus of elasticity, with a reduction in elongation% as compared with the onyx matrix tensile performance reported at room temperature. Fracture analysis reveals continuous carbon fiber pull out for onyx–carbon fiber samples tested at room temperature and cryogenic temperatures, suggesting weak onyx matrix–continuous carbon fiber adhesion.

To the best of the authors’ knowledge, this study is the first study to report on the cryogenic tensile properties and fracture response exhibited by 3D-printed onyx–continuous carbon fiber composites. Evaluating the viability of common commercial 3D printing techniques in producing composite parts to withstand cryogenic temperatures is of critical import, for aerospace applications.

The purpose of this study is to highlight the direct fabrication of rapid tooling (RT) with desired mechanical, tribological and thermal properties using fused deposition modelling (FDM) process. Further, the review paper demonstrated development procedure of alternative feedstock filament of low-cost composite material for FDM to extend the range of RT applications.

The alternative materials for FDM and their processing requirements for fabrication in filament form as reported by various researchers have been summarized. The literature demonstrates the role of various post-processing techniques on surface finish of FDM prints. Further, low-cost materials for feedstock filament have been investigated experimentally to check their adaptability/suitability for commercial FDM setup. The approach was to realize the requirements of FDM (melt flow rate, flexibility, stiffness, glass transition temperature and mechanical strength), necessary for the successful run of an alternative filament. The effect of constituents (additives, plasticizers, surfactants and fillers) in polymeric matrix on mechanical, tribological and thermal properties has been investigated.

It is possible to develop composite material feedstock as filament for commercial FDM setup without changing its hardware and software. Surface finish of the parts can further be improved by applying various post-processing techniques. Most of the composite parts have high mechanical strength, hardness, thermal stability, wear resistant and better bond formation than standard material parts.

Future research may be focused on improving the surface quality of parts fabricated with composite feedstock, solving issues related to the uniform distribution of filled materials during the fabrication of feedstock filament which in turns further increases mechanical strength, high dimensional stability of composite filament and transferring the technology from laboratory scale to various industrial applications.

Potential applications of direct fabrication with RT includes rapid manufacturing (RM) of metal-filled parts and ceramic-filled parts (which have complex shape and cannot be rapidly made by any other manufacturing techniques) in the field of biomedical and dentistry.

This new manufacturing methodology is based on the proper selection and processing of various materials and additives to form high-performance, low-cost composite material feedstock filament (which fulfil the necessary requirements of FDM process). Finally, newly developed feedstock filament material has both quantitative and qualitative advantage in RT and RM applications as compared to standard material filament.

This study aims to evaluate and assess the elastoplastic properties of Ti-6Al-4V alloy manufactured by Arcam Q20 Plus electron beam melting (EBM) machine by a tensile test campaign and micro computerized tomography (microCT) imaging.

ASTM E8 tensile test specimens are designed and manufactured by EBM at an Arcam Q20 Plus machine. Surface quality is improved by machining to discard the effect of surface roughness. After surface machining, hot isostatic pressing (HIP) post-treatment is applied to half of the specimens to remove unsolicited internal defects. ASTM E8 tensile test campaign is carried out simultaneously with digital image correlation to acquire strain data for each sample. Finally, build direction and HIP post-treatment dependencies of elastoplastic properties are analyzed by F-test and t-test statistical analyses methods.

Modulus of elasticity presents isotropic behavior for each build direction according to F-test and t-test analysis. Yield and ultimate strengths vary according to build direction and post-treatment. Stiffness and strength properties are superior to conventional Ti-6Al-4V material; however, ductility turns out to be poor for aerospace structures compared to conventional Ti-6Al-4V alloy. In addition, micro CT images show that support structure leads to dense internal defects and pores at applied surfaces. However, HIP post-treatment diminishes those internal defects and pores thoroughly.

As a novel scientific contribution, this study investigates the effects of three orthogonal build directions on elastoplastic properties, while many studies focus on only two-build directions. Evaluation of Poisson’s ratio is the other originality of this study. Furthermore, another finding through micro CT imaging is that temporary support structures result in intense defects closer to applied surfaces; hence high-stress regions of structures should be avoided to use support structures.

The purpose of this paper is to fabricate Nylon6-Al-Al2O₃-based alternative fused deposition modeling process (FDM) feedstock filament in place of commercial acrylonitrile butadiene styrene (ABS) filament (having required rheological and mechanical properties) for rapid manufacturing (RM) and rapid tooling (RT) applications. The detailed steps for fabrication of alternative FDM feedstock filament (as per field application) with relatively low manufacturing cost and tailor-made properties have been highlighted.

The rheological and mechanical suitability of nylon6-Al-Al2O₃ feedstock filament has been investigated experimentally. The approach is to predict and incorporate essential properties such as flow rate, flexibility, stiffness and mechanical strength at processing conditions and compared with commercial ABS material. The proportions of various constituents have been varied to modify and improve rheological behavior and mechanical properties of alternative FDM feedstock filament.

The alternative material of feed stock filament was successfully developed and loaded in commercial FDM setup without changing any hardware and software. The result of study suggests that the newly developed composite material filament has relatively poor mechanical properties but have highly thermal stability and wear resistant as compared to ABS filament and hence can be used for tailor-made applications.

In this work, no additive was added for improving the bond formation of metal and polymeric materials. The newly developed filament was prepared on single screw extruder. For more uniform mixing of metal and polymeric materials, further studies may be conducted on twin screw extruder. Also, for the present research work, the testing of newly developed filament has been limited up to mechanical testing, which may be extended to chemical and thermal analysis to understand thermal stability and degradation mechanism of newly developed composite material.

The proportion of filler material (Al-Al2O3) in Nylon6 matrix was set as a constraint, which was adjusted based upon melt flow index of original equipment manufacturer developed material (ABS), and temperature conditions were available at FDM nozzle (so that hardware and software system of commercial FDM setup need not to be altered).

The present approach outlined selection, processing, fabrication and testing procedure for alternate feedstock filament, which fulfills the necessary requirements of FDM process and has been customized for RT and RM applications. This work highlights mechanical strength evaluation of feedstock filament (which is necessary before the loading of material in FDM system). The potential applications of this investigation include RM of functional parts, tailor-made grinding tools for dentists and RT of metal matrix composite having complex geometry.

This study aims to understand the current production scenario emphasizing the significance of green manufacturing in achieving economic and environmental sustainability goals to fulfil future needs; to determine the viability of particular strategies and actions performed to increase the process efficiency of electrical discharge machining; and to uphold the values of sustainability in the nonconventional manufacturing sector and to identify future works in this regard.

A thorough analysis of numerous experimental studies and findings is conducted. This prominent nontraditional machining process’s potential machinability and sustainability challenges are discussed, along with the current research to alleviate them. The focus is placed on modifications to the dielectric fluid, choosing affordable substitutes and treating consumable tool electrodes.

Trans-esterified vegetable oils, which are biodegradable and can be used as a substitute for conventional dielectric fluids, provide pollution-free machining with enhanced surface finish and material removal rates. Modifying the dielectric fluid with specific nanomaterials could increase the machining rate and demonstrate a decrease in machining flaws such as micropores, globules and microcracks. Tool electrodes subjected to cryogenic treatment have shown reduced tool metal consumption and downtime for the setup.

The findings suggested eco-friendly machining techniques and optimized control settings that reduce energy consumption, lowering operating expenses and carbon footprints. Using eco-friendly dielectrics, including vegetable oils or biodegradable dielectric fluids, might lessen the adverse effects of the electrical discharge machine operations on the environment. Adopting sustainable practices might enhance a business’s reputation with the public, shareholders and clients because sustainability is becoming increasingly significant across various industries.

A detailed general review of green nontraditional electrical discharge machining process is provided, from high-quality indexed journals. The findings and results contemplated in this review paper can lead the research community to collectively apply it in sustainable techniques to enhance machinability and reduce environmental effects.

As more stringent environmental legislation is enforced throughout Europe manufacturing businesses, employing metal cutting processes, can no longer ignore the growing importance of environmental aspects relating to cutting fluids. Businesses, through market forces, are being forced into offering a “clean solution” to the metal cutting processes which they operate. Cutting fluids despite playing an important role in metal cutting, have considerable environmental impact. There is a need therefore to understand the role of cutting fluids within the cutting process in order to evaluate possible environmentally friendly alternatives to the use of cutting fluids. In order to achieve this the operating environment in which the process is being carried out, and the consequences of removing the cutting fluid from the process altogether has to be assessed. This paper therefore, reflects on the role of cutting fluid and the implications of their use. Viable methods of reducing cutting fluid consumption are also reported, together with efficient methods of cutting fluid utilisation (e.g. minimum quantity delivery systems). Finally, the difficulties experienced in removing cutting fluids from the metal cutting process are highlighted through the consideration of dry cutting technologies.

The purpose of this paper is to propose and evaluate the selection of materials for the selective laser sintering (SLS) process, which is used for low-volume production in the engineering (e.g. light weight machines, architectural modelling, high performance application, manufacturing of fuel cell, etc.), medical and many others (e.g. art and hobbies, etc.) with a keen focus on meeting customer requirements.

The work starts with understanding the optimal process parameters, an appropriate consolidation mechanism to control microstructure, and selection of appropriate materials satisfying the property requirement for specific application area that leads to optimization of materials.

Fabricating the parts using optimal process parameters, appropriate consolidation mechanism and selecting the appropriate material considering the property requirement of applications can improve part characteristics, increase acceptability, sustainability, life cycle and reliability of the SLS-fabricated parts.

The newly proposed material selection system based on properties requirement of applications has been proven, especially in cases where non-experts or student need to select SLS process materials according to the property requirement of applications. The selection of materials based on property requirement of application may be used by practitioners from not only the engineering field, medical field and many others like art and hobbies but also academics who wish to select materials of SLS process for different applications.

Electron beam-based additive manufacturing (EBAM) is an emerging technology to produce metal parts layer-by-layer. The purpose of this paper is to systematically address the research and development carried out for this technology, up till now.

This paper identifies several aspects of research and development in EBAM.

Electron beam has several unique advantages such as high scanning speed, energy efficiency, versatility for several materials and better part integrity because of a vacuum working environment.

This paper provides information on different aspects of EBAM with the current status and future scope.