Development Of Manufacturing Technology Research Articles

Features of Au(80)Sn(20) thin film solder manufacturing technology

This work provides the results of manufacturing technology development for Au(80)Sn(20) thin film solders produced with electron-beam evaporation coating of alternating gold and tin layers. The phase formation mechanism in the produced solders was studied to work out an evaporation procedure which enables to make a solder with the properties meeting the requirements to soldering of a laser diode onto a heatsink base surface.

A review of open source ventilators for COVID-19 and future pandemics

Coronavirus Disease 2019 (COVID-19) threatens to overwhelm our medical infrastructure at the regional level causing spikes in mortality rates because of shortages of critical equipment, like ventilators. Fortunately, with the recent development and widespread deployment of small-scale manufacturing technologies like RepRap-class 3-D printers and open source microcontrollers, mass distributed manufacturing of ventilators has the potential to overcome medical supply shortages. In this study, after providing a background on ventilators, the academic literature is reviewed to find the existing and already openly-published, vetted designs for ventilators systems. These articles are analyzed to determine if the designs are open source both in spirit (license) as well as practical details (e.g. possessing accessible design source files, bill of materials, assembly instructions, wiring diagrams, firmware and software as well as operation and calibration instructions). Next, the existing Internet and gray literature are reviewed for open source ventilator projects and designs. The results of this review found that the tested and peer-reviewed systems lacked complete documentation and the open systems that were documented were either at the very early stages of design (sometimes without even a prototype) and were essentially only basically tested (if at all). With the considerably larger motivation of an ongoing pandemic, it is assumed these projects will garner greater attention and resources to make significant progress to reach a functional and easily-replicated system. There is a large amount of future work needed to move open source ventilators up to the level considered scientific-grade equipment, and even further work needed to reach medical-grade hardware. Future work is needed to achieve the potential of this approach by developing policies, updating regulations, and securing funding mechanisms for the development and testing of open source ventilators for both the current COVID19 pandemic as well as for future pandemics and for everyday use in low-resource settings.

Fabrication and functions of graphene-molecule-graphene single-molecule junctions.

The past two decades have witnessed increasingly rapid advances in the field of single-molecule electronics, which are expected to overcome the limitation of the miniaturization of silicon-based microdevices, thus promoting the development of device manufacturing technologies and characterization means. In addition to this, they can enable us to investigate the intrinsic properties of materials at the atomic- or molecular-length scale and probe new phenomena that are inaccessible in ensemble experiments. In this perspective, we start from a brief introduction on the manufacturing method of graphene-molecule-graphene single-molecule junctions (GMG-SMJs). Then, we make a description on the remarkable functions of GMG-SMJs, especially on the investigation of single-molecule charge transport and dynamics. Finally, we conclude by discussing the main challenges and future research directions of molecular electronics.

Design and additive manufacturing of closed cells from supportless lattice structure

In nature, mesoscopic or microscopic cellular structures like trabecular bone, wood, shell, and sea urchin, can have high load-carrying capacity. These cellular structures with diverse shapes, forms and designs can be mainly classified into open and closed cell cellular structures. It is difficult to replicate these natural complex lattice structures with traditional manufacturing, but additive manufacturing (AM) technology development has allowed engineers and scientists to mimic these natural structures. Fabricating close cell lattice structures is still considered difficult due to the support structure within the lattices. This paper evaluates a novel way of fabricating a close cell lattice structure with a material extrusion process. The design eliminates the need for support structures and the subsequent post-processing required to remove them. A shell-shaped close cell lattice structure bio-mimicking a sea urchin shape was introduced for the load-bearing structure application. The mechanical properties of the proposed structure, including stiffness, deformation behavior and energy absorption, were compared with those of benchmarked honeycomb and open cell sea urchin (SU) lattice structures of the same density. SU lattice structures and honeycomb periodic lattice structures with varied sizes but the same morphology and fixed density were designed and printed in polylactic acid material (PLA). Their physical characteristics, deformation behavior, and compressive properties were investigated experimentally and via finite element analysis. The effect of the unit cell size on mechanical properties was studied and discussed, and the rankings of better performances were drawn. A possible application of the closed cell is for fabricating the load bearing structure; it can also be encapsulated within a fluid to impart strength and damping characteristics.

STRUCTURE AND TRIBOTECHNICAL PROPERTIES OF COMPOSITE ANTIFRICTION MATERIALS BASED ON R7M2F6 STEEL WASTE

Background. Development of the technological measures for creating new antifriction composite materials based on waste powders of steel P7M2F6 with solid lubricant CaF2, intended for operation at temperatures up to 600 °C, sliding speeds up to 1 m/s, loads up to 5.0 MPa in air.Objective. The purpose of the paper is to determine the features of structure formation and their influence on the properties of composite antifriction materials based on industrial grinding waste of steel P7M2F6 with solid lubricant CaF2 for operation at high temperature friction units in air.Methods. Methodology consisted of the development of the regeneration technological modes of the industrial grinding waste of steel P7M2F6, determination of technological manufacturing operations for new antifriction composites that include mixing of steel powders with solid lubricant, pressing and sintering of composites. The study of the structure formation processes and properties of materials was carried out using optical and electron microscopy methods, standard methods for determining mechanical properties and tests for friction and wear.Results. The influence of the developed manufacturing technology on the formation of the structure, physical mechanical and tribotechnical properties of materials based on steel P7M2F6 grinding waste with solid lubricant CaF2 additives was determined and grounded; resulting is the formation of complex heterogeneous antifriction material with high functional characteristics. The new material’s structure formation and its influence on the functional properties after using the developed manufacture modes was shown. Micro-X-ray spectral analysis confirmed the fact that CaF2, the contact pair’s chemical elements and oxygen form an antifriction film that provides a self-lubrication mode at the determined friction temperatures.Conclusions. The possibility of predicting the structure and functional properties of antifriction self-lubricating composite materials at high temperatures by purposeful choice of starting metal grinding wastes for certain operation conditions of contact pair was shown.

An interactive approach towards the development of an additive manufacturing technology for railcar manufacturing

An interactive approach towards product development enables the creation of products which combine optimal performance with effective users’ interaction. In this work, an additive manufacturing technology which is suitable for manufacturing internal and external accessories of a railcar was developed using an interactive approach. The mechanical design of the body kit, which consists of the frame vertex triangle, front threaded and smooth rods, NEMA 17 stepper motor, micro-switch and extruder, was done using the Autodesk Inventor® 2016 while the finite element analysis of its extruder was done using the Commercial Abaqus software 2018. Also, the electronics board which controls the 3D printing process comprises of the MELZI V2.0, a DIY shield board, USB to serial converter and Arduino micro controller. A software program using process G-code instruction in the Arduino micro controller in conjunction with MELZI board and additional circuit was employed to control the sensors used as input. During the performance evaluation, the 3D printing technology was used to produce the circular and non-circular gears. The results obtained indicate that an increase in the feed rate and nozzle diameter results in an increase in the speed of printing but with a reduction in the print quality and vice versa. Hence, the developed 3D printing technology offers the realistic possibility for easy and quick, production of products on demand, thus, enabling product development and customization which has the potential to boost innovation and foster more efficient use of resources.

Machinability of PA12 and short fibre–reinforced PA12 materials produced by fused filament fabrication

Fused filament fabrication (FFF) is an extrusion-based process that allows quick and inexpensive part production, practically without any geometric limitations, offering flexibility, promoting reduction in costs and lead-time in an industrial scenario. Being one of the most widespread additive manufacturing techniques, the process has evolved introducing new and advanced materials (e.g. high-performance polymers and composites). Despite its advantages, the process is vastly overlooked due to its high level of anisotropy, poor surface roughness and lack of geometric accuracy caused by the layer thickness. To reduce this effect, a sequence of laborious manual operations can be performed, which may result in time-consuming and inaccurate results. Therefore, efforts have been made towards the development of hybrid manufacturing technologies by combining FFF process and subtractive equipment, aiming to solve these limitations. In this work, two complementary methodologies analysing the behaviour of FFF PA12 and short fibre–reinforced PA12 printed parts when subjected to a subtractive approach are presented. The first experimental plan took into account the final surface roughness (Ra and Rz) via full factorial design of experiments (DOE) and analysis of variance (ANOVA) considering the influence of distinct printing orientations, two types of cutting tools and machining parameters such as, cutting speed, feed and cutting depth. An analysis on tool wear and SEM microscopy to the machined surface was also performed. The second approach was carried out via Taguchi and ANOVA, considering the first experimental approach results. Thus, milling parameters were the focus, evaluating the final material surface roughness, being now monitored the cutting forces and tool wear analysis in order to understand their influence on the final results. It is shown that it is possible to machine PA12-based FFF printed parts without any major problems such as layer delamination. A decrease in Ra, t of 1931% to 0.99 μ m for PA12CF and 2255% for PA12 to 0.96 μ m was achieved, proving the overall machinability of the materials. It was found that PA12 creates higher levels of cutting loads and increased tool wear, thus indicating that short fibre presence improves the material machinability, while parameters such as building orientation do not possess any influence on the final surface roughness.

Controlling the Properties of Additively Manufactured Cellular Structures Using Machine Learning Approaches

Cellular structures are lightweight‐engineered materials that have gained much attention with the development of additive manufacturing technologies. This article introduces a precise approach to predict the mechanical properties of additively manufactured lattice structures using deep‐learning approaches. Diamond‐shaped nodal lattice structures are designed by varying strut length, strut diameter, and strut orientation angle. The samples are manufactured using laser powder bed fusion (LPBF) of Ti−64 alloy and subjected to compression testing to measure the ultimate strength, elastic modulus, and specific strength. Machine learning approaches such as shallow neural network (SNN), deep neural network (DNN), and deep learning neural network (DLNN) are developed and compared to the statistical design of experiment (DoE) approach. The trained DLNN model show the highest performance when compared with DNN, DoE, and SNN with a mean percentage error of 5.26%, 14.60%, and 9.39% for the ultimate strength, elastic modulus, and specific strength, respectively. The DLNN model is used to create process maps, and is further validated. The results show that although deep learning is preferred for big data, the optimized DLNN model outperform the statistical DoE approach and can be a favorable tool for lattice structure prediction with limited data.

Геометрия неидеальных объектов в судостроении и судоремонте

The article considers the modern engineering practice of designing and manufacturing that uses various analytical and graphic forms representing geometric objects. Both of these forms are characterized by the presence of two problems in terms of production practice: 1 - tools of modern geometry cannot operate with non-ideal forms and configurations of material objects; 2 - lack of methods and tools for describing patterns of generating geometric objects, from production lines to the structure that characterizes the relative location of surfaces. The generalized provisions of the geometry of non-ideal objects theoretically justified for formal synthesis and their elements have been presented, which avoids problems of geometric configuration in the practice of designing and developing manufacturing technologies in shipbuilding and ship repair. A special toolkit based on discrete mathematics is proposed for the formal description of the geometric configuration of non-ideal objects. The principles of geometry of real objects describe the structural-parametric representation of objects in a six-dimensional space that is defined by linear and angular vectors. The concepts of linear and angular vectors are analyzed. It has been stated that the presence of an angular vector simplifies the perception and makes easier calculating the processes of geometric transformations. A geometrical object refers to a closed subspace bounded by a single surface, a set of mating or intersecting surfaces. The examples of the real plane deviations from its reference, location of the planes for creating the ideal geometric configuration, variants of real images, forming the basis for six-dimensional space, structure of geometric configurations have been illustrated. It has been found that any specific part acting as a geometric object can be represented by a set of surfaces and the structure of their relationships, which contributes to the correctness of its manufacture. The use of six-dimensional space allows to describe the spatial geometric configurations of parts of various mechanisms with mathematical accuracy.

Decomposition and Aggregation-Based Real-Time Analysis of Assembly Systems With Geometric Machines and Small Batch-Based Production Tasks

Steady-state analysis on production systems, especially serial lines with rigid production mode, have been carried out in a large amount of research literature. With the development of the advanced manufacturing technologies, as well as the national strategies, for example, Made in China 2025, real-time performance evaluation, prediction, production management, and efficient control of systems with flexible production mode are gradually becoming important issues. Under the assumption of assembly systems with small batch-based production tasks, we develop a mathematical model for the real-time performance analysis of such systems with the geometric machine reliability model, which is applicable in many manufacturing environments. The formulas for real-time performance analysis are derived first using the Markovian approach for three-machine assembly systems. Then, based on the idea of decomposition and aggregation, an algorithm with high accuracy and efficiency for system real-time performance approximation is proposed. Finally, the decomposition and aggregation-based real-time analysis approach is extended to the generalized assembly systems. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —As the concept of manufacturing intelligence being proposed and promoted, system flexibility appears frequently in production in recent years. A flexible production refers to the implementation of small batch-based production with multitype of products on the same production line, by quick setup or machine adjustments. The steady-state analysis method that is traditionally used might be not applicable in this case since most of the production process is in transient state. An approximation-based analytical method, for real-time performance evaluation of assembly systems with small batch-based production tasks and with machines having the geometric reliability model, is proposed. The algorithm developed in this article can be utilized by production managers and engineers, with which the real-time performance of the systems can be predicted with high accuracy. It can also provide assistance for decision-making on activities of production control.

Possibilities and challenges of constant shear rate test for evaluation of structural build-up rate of cementitious materials

The rapid development of additive manufacturing technologies in the construction industry has heightened interest in the accurate estimation of the structural build-up rates of cementitious materials, especially in in-situ conditions. For this purpose the constant shear rate (CSR) test performed by rotational rheometers using the single-batch approach can be applied. The paper at hand presents possibilities in improving the methodology of experiments and data analysis in the CSR test, for particular rheometers, and discusses both the features and limitations of the test. The breaking criterion is proposed for the CSR tests to prevent excessive deformation in a single sample measurement. Evaluation of the elastic properties of cementitious materials by the CSR test is assessed; two approaches for the characterisation of structural build-up rate based on proportionality limit and flow onset points are compared. The findings are illustrated for the examples of cement paste and cementitious mortars tested using two different types of rotational rheometers.

A novel design method for 3D positive and negative Poisson's ratio material based on tension-twist coupling effects

In recent years, as the development of additive manufacturing technology, 3D negative Poisson’s ratio (NPR) materials attract many researchers’ interest. In this paper, a novel 3D NPR material design method based on the tension-twist coupling effect has been proposed. A novel category of 3D NPR and positive Poisson’s ratio (PPR) materials by linking multilayer 2D NPR materials through 3D chiral chains are proposed. The sign of the Poisson’s ratio depends on the linkage pattern of the 3D chiral chain. Based on this method, 11 types of novel 3D NPR and PPR materials are presented. Experimental and numerical methods are adopted to study the mechanical properties of the proposed novel 3D NPR and PPR materials. Results show that the novel 3D materials present desirable NPR and PPR as we expected, which proved the effectiveness of the proposed design method.

Highly Conductive Graphene Electronics by Inkjet Printing

Graphene is currently emerging as an alternative to traditional conductive materials, such as copper and silver because of its excellent electrical conductivity and earth's carbon abundance. Graphene can be applied in many different electronic fields with different manufacturing methods to meet their specific requirements, which promote the development of advanced manufacturing technology in graphene electrical applications. Inkjet printing, as an environmentally friendly, low-cost and simple-to-operate advanced manufacturing method, has broad development prospects especially in the field of flexible electronics. In this review, several factors affecting the electrical conduction property of graphene applications in the inkjet-printed graphene process are listed as follows: the preparation method of ink, material and treatment of substrate, thickness of print, and annealing, especially whether a coffee ring is produced. In addition, this paper also cites some examples of inkjet-printed graphene in electrical conductivity. In order to continuously improve the procedure designs of graphene electronics fabrication, more accurate relationships between electrical conductivity of graphene and these parameters can be built. Based on the excellent prospect of inkjet printing technology in the field of conductive electronics, there will be some further research about the perfect implementation of graphene’s electrical conductivity.

ELECTRON-BEAM MELTING OF INGOTS OF TiAl SYSTEM INTERMETALLICS

Performance of scientific-technical researches at the E. O. Paton Electric Welding Institute of the NAS of Ukraine have been directed on development of technology for manufacture of titanium aluminide –based alloys using the method of electron-beam melting (EBM). The mathematical models of heat state and evaporation of alloying elements in EBM were developed. The results of calculations of heat state using the mathematical model allowed determining a dependence of depth of liquid pool on different melting rates. The mathematical models of processes of evaporation in EBM of titanium aluminide ingots were used for plotting the nomograms, which help to determine the necessary content of alloying element of the alloy in the initial charge for acquiring the necessary concentration of this element in ingot at set technological parameters of melting. In scopes of designed mathematical models there were investigated different technological modes of electron-beam melting of ingots based on titanium aluminide. The optimum EBM modes, at which a solidification front approaches to flat, were determined. At that, more uniform distribution of the additives on ingot section and volume is provided as well as level of stressed state is reduced. The works were carried out on manufacture of titanium aluminide based-ingots with addition of refractory as well as volatile alloying elements. Composition and structure of produced ingots were examined. It is shown that electron-beam melting allows getting chemically homogeneous ingots based on titanium aluminide and is a perspective method for production of such class materials.

Development of manufacturing technology and quality control methods for solid-drawn cylinders from AMg5 alloy

Development of manufacturing technology and quality control methods for solid-drawn cylinders from AMg5 alloy

Розробка технології виготовлення та впровадження нового класу інструменту з CVD-алмазу для шліфування високоточних зубчастих коліс спеціальних редукторів

Розробка технології виготовлення та впровадження нового класу інструменту з CVD-алмазу для шліфування високоточних зубчастих коліс спеціальних редукторів

Опыт разработки технологии изготовления модельной оснастки для отливок с применением СAD/CAM/CAE систем

Опыт разработки технологии изготовления модельной оснастки для отливок с применением СAD/CAM/CAE систем

Metal Powder and Wire Additive Manufacturing Technology

Additive manufacturing technology can quickly manufacture parts with dense microstructures and excellent mechanical properties, so that it shows a broad application prospect in aerospace and other fields. Additive manufacturing technology was briefly introduced in this paper. On this basis, the technology and characteristics of metal powder and wire additive manufacturing were systematically analyzed and compared, and the development of additive manufacturing technology was prospected.

Development of the titanium meshes by selective laser melting and chemical etching for using as medical implants

The development of additive manufacturing technology has allowed to begin the implementation of the concept of personalized implants in medicine. Medical implants should have not only mechanical properties close to bone tissue, but also have good biocompatibility, antibacterial and osseointegrating properties. These characteristics are determined by the relief, morphology, and composition of surface and can be modified by various methods such as etching, coating, electrochemical and chemical modification etc. In this research we produced the mesh-type implants by selective laser melting (SLM) and modified their relief and morphology of surface by chemical etching. Titanium VT1-0 powder was used as a raw material for SLM. For chemical etching we used three type of solutions: mixtures of H2SO4/HCl, H2SO4/H2O2 and NH4OH/H2O2. The surface morphology of etched implants was studied by scanning electron microscopy (SEM). Results showed that NH4OH/H2O2 solution is the most promising for formation of the surface with developed relief.

Development of Laser Additive Manufacturing Technology for Metals

Laser additive manufacturing (LAM) technology for metals is one of the key fundamental technologies for realizing intelligent manufacturing in fields such as aeronautics, astronautics, and medicine. This study summarizes the current status and trends of the LAM technology for metals in China and abroad using questionnaires, on-site surveys, and literature review. It also analyzes the gap between China’s technology development and the international advanced level and proposes a tentative strategy for the development of the LAM technology in China, hoping to provide support for the top design of national technological and industrial strategies and for the formulation of development goals for the LAM technology by 2035. Currently, the research on LAM technology focuses on active control of structure properties while comparatively ignoring control of geometric shapes in LAM. To satisfy the requirements of high-quality manufacturing, process monitoring of LAM equipment is highly valued. To improve the manufacturing capability and efficiency of high-value components, hybrid additive/subtractive manufacturing equipment has become a new research and development hotspot. The sound development of the LAM industry requires integration among the whole industrial chain including material, process, equipment, test, standards, and personnel training. China should fully explore the functions of the material genome technology for strengthening its fundamental research and improve its independent development capacity of core components and research on equipment integration. Moreover, the engineering application of the LAM technology should be conducted gradually.