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Machining of metal matrix composites (MMC) is a challenging process as they are difficult to cut and cutting tools get worn out in a short time. In this paper, the performance of two industrial carbide grades and a cubic boron nitride (CBN) tool are assessed when machining of AZ91/SiC composites. Mg-based composites with different volume fractions and particle sizes are machined at various cutting conditions to evaluate the tools wear resistance and finished surface. The surface of the worn-out tools and machined samples are analyzed by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and roughness tester. Results revealed that the tool wear increased for composites reinforced by smaller particles regardless of the tool type. Additionally, tool grade TH1000 resulted in longer tool life when machining of Mg-based composites compared to the CP500 grade so that at a cutting speed of 70 m/min and feed rate of 0.1 mm/rev, tool life improved nearly 250%. CBN tools showed the best performance when machining of Mg-based composites as tools became worn out after 255 s which is considerable compared to carbide tools. Also, the finished surface caused by cemented carbide CP500 indicated the worst quality. [ABSTRACT FROM AUTHOR]

Aiming at the distributed unrelated parallel machine scheduling problem with machining constraints, this paper proposed an extended empire competition algorithm to solve the problem, which took the total transportation cost, evaluation function for simultaneous shutdown of parallel machines among factories and equilibrium evaluation function for average switching frequency of workpiece types among factories as optimization objectives. Based on the original empire competition algorithm, this algorithm added an initial factory-workpiece sequence group suitable for factory assignment. According to the shortcoming of the traditional empire competition algorithm that it was easy to fall into the local optimum, this paper divided the inferior sequence assimilation into the external assimilation mechanism and the internal assimilation mechanism. The extended empire competition algorithm combined local and global search methods to realize the intelligent search behavior. This paper used the partial matching crossover and single point mutation to update the factory-workpiece sequence group and ensure the diversity of the factory-workpiece sequence. Finally, this paper designed three different scales of 12 examples and verified the effectiveness of the proposed algorithm through simulation experiments. At the same time, this paper verified the advantages of the proposed algorithm in solving the distributed multi-objective unrelated parallel machine scheduling problem by comparing the research results in related fields. [ABSTRACT FROM AUTHOR]

Due to their high hardness at elevated temperatures and chemical stability, alumina-based ceramic cutting tools have been successfully applied in the machining of ferrous materials, especially quenched and tempered steels. Their low fracture toughness, however, makes it difficult to finish them by grinding, as cracks and defects can occur. In addition, its application in machining processes demands appropriate edge preparation to avoid tool failure. Within this context, the paper aims to demonstrate the applicability of an experimental Al2O3 + MgO ceramic cutting insert in hard turning. For this, grinding tests were performed to determine the most appropriate conditions to improve its surface and edge quality. The effects of cutting and feed speeds, grinding wheel bonding material, and abrasive grain size were investigated. Moreover, different cutting-edge geometries were prepared in this tool material and tested in turning a hardened AISI 4140 steel (50 HRC) to determine their performance regarding tool life and workpiece roughness. The results demonstrated that a finer grinding wheel (D15) combined with high cutting (60 m/s) and feed (10 mm/min) speeds leads to the lowest surface roughness and edge chipping. In addition, both symmetric (Κ = 1) and asymmetric (Κ = 2) edge roundings led to higher tool lives in hard turning in comparison to a single chamfered tool, as they contributed to better load distribution in the cutting region. The paper provides information for the manufacture and application of alumina-based ceramic cutting inserts in the metalworking industry, as it disseminates good manufacturing practices and recommendations for appropriate cutting-edge geometry. [ABSTRACT FROM AUTHOR]

The requirement for high-speed and high-precision contouring with free-form surfaces in the CNC machining process is increasing. The contour error is an essential criterion for the quality of CNC machining. For the problem of contour error control, the present research is mainly based on position tracking, and the control method directly aiming at contour control has not been well studied. This paper proposed a new type of coordinate transformation-based direct contour control method (CT-DCC) for free-form surface machining trajectories. By real-time monitoring of the contour error and the foot point of the free-form parametric trajectory, the contouring task is decomposed into the contour error control task in the normal direction and the velocity control problem in the feed direction. Using coordinate transformation, the output commands of the two tasks are converted to the axial motion command. CT-DCC completely eliminates position tracking in the traditional control to achieve direct control of the contour error, which provides a new solution for the contour control problem of free-form surface machining. Both the axial velocity control and the axial torque control-based CT-DCC scheme were studied, and the two-axis and three-axis direct contour controllers were tested. The simulation and experiment results show the feasibility of the proposed method. [ABSTRACT FROM AUTHOR]

This paper presents an innovative and comprehensive methodology for loaded tooth contact analysis (LTCA) of spiral bevel gears, integrating ease-off surface computation with high-precision virtual generating tooth surfaces. The methodology integrates an error-sensitivity analysis model with a semi-analytical LTCA model for spiral bevel gears based on ease-off surfaces, developed using a Universal Generation Model. By leveraging sophisticated corrections in the machining process, the desired ease-off surfaces are obtained, ensuring the accuracy of the generated tooth surfaces. This simulation ensures minimal errors between theoretical and virtual generating tooth surfaces, providing a reliable basis for LTCA. The LTCA model is formulated using CNC-generated tooth surfaces, focusing on misalignments such as pinion offset, adjustment errors, and angular position errors along the pinion and gear axis. The feasibility and effectiveness of the proposed method are verified through comparisons with LTCA software analysis results, demonstrating its high accuracy in predicting the impact of misalignments on contact patterns and load distribution. This integrated approach offers significant advancements in the design and analysis of spiral bevel gears, providing a robust tool for predicting and analyzing gear performance under various misalignment conditions. The combined methodology enhances the reliability and accuracy of LTCA, ensuring optimal performance and durability of spiral bevel gears in practical applications. [ABSTRACT FROM AUTHOR]

Shape memory alloys (SMAs) are potential materials in various areas such as engineering and medicine, and their applications are being studied for practical use. SMAs show competence in their main material properties in response to their working environment or external stimuli. Machining of NiTiCu10 SMAs is difficult using traditional machining because of their wide-ranging mechanical properties like high toughness, strength, and sensitivity to phase transformation temperature. Nonconventional machining methods such as electro-discharge machining (EDM) are suitable for effective machining SMAs. The work material NiTiCu10 SMA has been used in this study, and processed using the vacuum induction melting (VIM) technique. The addition of copper leads to increase in the martensitic transformation temperatures. This paper focuses on the electro-discharge drilling (EDD) of NiTiCu10 SMA using copper tool electrode. Experimental analysis of performance criteria has been evaluated by conducting experiments following one factor at a time (OFAT) approach. Machining features such as material removal rate (MRR), tool electrode wear rate (TEWR), and surface roughness (SR) have been studied by considering pulse current ( I p ), gap voltage ( V g ), pulse on time ( T on ), pulse off time ( T off ), and rotational speed of tool electrode (N). Experimental results have shown that machining at the highest I p of 12 A yields the highest MRR with the value of 4.077 mm3/min, whereas mcahining at T on of 15 μ s yields the lowest TEWR with the value of 0.031 mm3/min. The lowest SR is 2.8 μ m achieved at the lowest T on of 15 μ s. Surface morphology is significant in quality evaluation in the manufacturing, and building industries because it directly determines the mechanical performance of parts, and the service life of products. Morphological investigation via scanning electron microscope (SEM) has confirmed the formation of craters, debris, microcracks, and resolidified layers. The benefit of this study has been that we have been able to select the range of significant control factors, and predict their levels, for decisive experimentation. [ABSTRACT FROM AUTHOR]

This paper delves into the formability of material deposited by wire arc additive manufacturing. It presents a novel dieless Nakajima testing procedure that offers a practical solution for obtaining strain loading paths up to failure directly from the deposited material without the need for extracting sheet blanks. The procedure involved machining a region of the deposited material to the desired shape and thickness and using a press to drive and control the movement of a hemispherical punch. The test was designed using finite element modeling, and its effectiveness in obtaining the required strain loading paths directly from the deposited material was verified through experimentation with digital image correlation. Importantly, this novel test eliminates the need for the special-purpose tool setup required in conventional Nakajima sheet formability tests, thereby simplifying the overall testing process. [ABSTRACT FROM AUTHOR]

Precise electrochemical machining (PECM) is being used increasingly to produce turbine blades (high-pressure compressors) from difficult-to-machine materials such as Inconel. However, the challenges associated with PECM are particularly pronounced for filigree workpieces characterized by high aspect ratios and thin-walled geometries. The need for high-pressure flushing within the working gap to renew the electrolyte poses a dilemma because it induces unwanted deflection in these thin-walled structures. This problem is intensified by the mechanical oscillation of the tool applied to promote flushing efficiency. The superposition of mechanical tool oscillation and turbulent flushing, which exacerbate fluid–structure interaction, has been identified as the essential cause of workpiece deflection. The aim of this paper is to present an experimental setup coupled with numerical methods to better investigate the phenomenon of workpiece deflection during PECM. In the first part of this work, a novel tool system for investigating the phenomenon of workpiece deflection in PECM is presented. The tool system combines typical PECM tool–workpiece arrangements for double-sided machining and a unique electrolytic mask that provides optical access to the working gap, allowing in situ measurements. After validating the tool system by experimental tests, the workpiece deflection is investigated using high-speed imaging. In a next step, analytical studies of the flushing conditions during machining operations are carried out. These investigations are followed by a structural investigation of the workpiece to improve the understanding of the deflection behavior of the workpiece. In addition, the effect on the blade tip caused by the continuously decreasing moment of inertia of the blade due to their thinning during machining is analyzed. [ABSTRACT FROM AUTHOR]

Double-sided planetary grinding (DSPG) with a fixed abrasive is widely used in sapphire substrate processing. Compared with conventional free abrasive grinding, it has the advantages of high precision, high efficiency, and environmental protection. In this study, we propose a material removal rate (MRR) model specific to the fixed-abrasive DSPG process for sapphire substrates, grounded in the trajectory length of abrasive particles. In this paper, the material removal rate model is obtained after focusing on the theoretical analysis of the effective number of abrasive grains, the indentation depth of a single abrasive grain, the length of the abrasive grain trajectory, and the groove repetition rate. To validate this model, experiments were conducted on sapphire substrates using a DSPG machine. Theoretical predictions of the material removal rate were then juxtaposed with experimental outcomes across varying grinding pressures and rotational speeds. The trends between theoretical and experimental values showed remarkable consistency, with deviations ranging between 0.2% and 39.2%, thereby substantiating the model's validity. Moreover, leveraging the insights from this model, we optimized the disparity in the material removal rate between two surfaces of the substrate, thereby enhancing the uniformity of the machining process across both surfaces. [ABSTRACT FROM AUTHOR]

Aerodynamic contour dimensional accuracy is very important for the stable and safe flight of aerospace vehicles. Nevertheless, due to the influence of various factors such as material properties, machining and manufacturing deviations, and assembly and installation deviations, key structural geometric dimensions are frequently exceeded. Therefore, this paper investigates a data-driven combined vector loop method (VLM)–Skin Model Shapes (SMS) method to realize aerospace vehicle structural geometric accuracy analysis; assembly optimization targeting contour deviation is also achieved. Tests are carried out on a typical aerospace vehicle's underconstrained structural workpieces to validate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

The desired Surface Roughness (SR) can be achieved via general machining methods by using a cutting tool to remove a material layer on the workpiece surface. Cutting Parameters (CP), cutting tool properties, and workpiece properties must be considered. The finishing machining methods that can be applied to produce the desired SR are turning, milling, grinding, boring, and polishing. The technological parameters must be tightly combined in the Machining Process (MP). The CP selection presents some issues regarding time, cost, and practical skill when considering different cutting methods, cutting tools, and workpiece materials. SR predicting methods of machined parts have the advantages of shortening the time of CP selection, reducing machining cost, and bringing the desired SR. This paper reviews the recent methods followed in predicting the SR of the MPs. The SR prediction methods will bring many benefits for MP, such as improved SR, reduced cost, improved cutting conditions, and enhanced quality. [ABSTRACT FROM AUTHOR]

To further enhance the performance of the fast tool servo (FTS) system in terms of stroke, load capacity, and application area, this paper proposes a novel fast tool servo device driven by a voice coil motor (VCM), based on a three-segment uniform corrugated flexure (CF) guiding mechanism, with a large stroke, high accuracy, and high dynamics. To describe the unified static characteristics of such device, the compliance matrix method is applied to establish its model, where the influence of CF beam structural parameters on the FTS device is investigated in detail. Furthermore, resolution and positioning accuracy tests are conducted to validate the features of the system. The testing results indicate that the maximum stroke of the FTS device is up to 3.5 mm and the positioning resolution values are 3.6 μm and 2.4 μm for positive and negative stroke, respectively, which further verifies the device's effectiveness and promising application prospect in ultra-precision microstructure machining. [ABSTRACT FROM AUTHOR]

Modern machining systems use horizontal and vertical data integration for the automatic monitoring and quality control of the machining operations. There are currently available some comprehensive papers focused on high-level system integration. Independently of that, there are also multiple publications focused on the automatic monitoring of specific machining operations. There is lack of presented connections between the high-level proposals and the operation-level methods. This paper proposes a framework for milling process monitoring that covers both mentioned levels, i.e., the system complexity as well as particular operation details. The data model consisting of five key objects (cutting tool management; machine tool; workpiece; machining operation and user) is presented within the framework. [ABSTRACT FROM AUTHOR]

Sea to space applications necessitate advanced materials to fulfill diverse requirements, including Titanium and its alloys, particularly Grade 5 (Ti-6Al-4V alloy). Exhibiting remarkable properties such as high heat resistance, low thermal conductivity, low weight ratio, and minimal corrosiveness, Titanium Grade 5 holds immense potential for applications in aerospace, biomedical, automotive, and military sectors. However, its full utilization is impeded by challenges encountered during machining. This paper provides an overview of the difficulties faced in machining Titanium Grade 5 and emphasizes the ongoing search for the optimal tool-material combination. The paper discusses the properties influencing machinability, such as thermal conductivity, chemical reactivity, elastic modulus, hardness, strength, work hardening, and the effects of temperature on Ti-6Al-4V alloy. The review emphasizes the various techniques employed to enhance machining efficiency, including dry cutting, flood cooling, minimum quantity lubrication, high-pressure coolant environment, cryogenic environment, solid lubricants, and hot machining. While the best pairing remains elusive, significant progress has been made in the machining of titanium alloys, showcasing various evolving techniques and methodologies aimed at enhancing the material's usability in diverse industrial applications. [ABSTRACT FROM AUTHOR]

This paper analyses some theoretical and philosophical concerns related to modular synthesis performance practice. Taking an interdisciplinary approach drawing upon concepts from cognitive archaeology, anthropology and the philosophy of technology, the paper seeks to frame modular synthesis practice as a dance of agencies in the context of human–machine performance. In this paper, I explore how musical ideas, technical objects and performances co-evolve as part of a set of interdependent practices. To contend with this entangled human–machine relationship, I propose a consideration of how material agency helps define the direction of these creative practices, through the process of material engagement. In doing so, we consider the unique ergodynamics of modular systems, and examine the interdependent relationship that exists between the two core sites of musical performance in this practice: that of 'patching', and of live performance. Through reflective practice and theoretical discussion, this paper analyses how an entanglement between human and material agencies challenges traditionally understood notions of musical authorship and agency. [ABSTRACT FROM AUTHOR]

This paper proposes an original method to determine the oil mist impingement over an insert based on different machining configurations (rotation velocities) and different inner canalization designs, without material removal, on milling tool. The oil mist spray is determined using different holders as an insert. Glass plate and blotting paper are used and evaluated in this work to get as much information as possible, based on micro–macro scale observations. The imprint size of the oil mist spray distribution, the particle sizes and the fluid film formation have been studied to determine the effects of the different configurations on the oil mist impingement behavior. The droplet impingements and distributions on the glass plate are analyzed under a 3-D profilometer (microscopic scale). On the blotting paper, the distributions are analyzed with pictures of the oil marks (macroscopic scale). This original method gives quite fast particle distributions that can be used in industry. The different experimental results give large information about the oil mist behavior sprayed on the glass plate. Increasing rotation velocities increases the oil mist amount in the cutting area. Increasing the canalization orientation design gives a better focused spray. The rake angle has strictly no influence on the oil mist spray distribution. But sputtering effects have been highlighted and should be avoided to keep MQL efficiency. [ABSTRACT FROM AUTHOR]

Unconventional machining methods include electrochemical micromachining (EMM). EMM is suitable for hard and difficult-to-cut materials used in the manufacture of special forms of machine parts used in aeronautics and hydro pneumatic machinery. As a result of a set of electrical, mechanical and chemical parameters, the EMM process is a very complex process. The analytical modeling of the method is therefore difficult. The artificial neural network (ANN) significantly simplifies the relationship between input and output parameters due to the large number of measurements required. With a set of data containing very different machining parameter choices, the neural network was trained. This paper presents the results obtained for predicting certain output parameters. The ANN is used in this paper to determine the model for parameter optimization. To represent the relationship between machining rate (MR), overcut (OC) and input parameters, an ANN model has been established that adapts the Levenberg-Marquardt algorithm and Bayesian regularization (LMABR). The model is shown to be efficient, and optimized machining parameter improves the MR and OC. [ABSTRACT FROM AUTHOR]

The steels from which the components of mining machinery are constructed must be based primarily on knowledge of their behaviour under environmental conditions and of the excavation technology. Secondly, the structural changes undergone by the materials due to mechanical and thermal processing and the stresses generated by the action of excavation forces that can induce internal stresses at a level that is difficult to determine must be taken into account. Determining the level of structural and mechanical degradation involves sampling the load-bearing structure elements of the excavation and storage machinery for analysis of the mechanical and chemical properties of the component materials. The paper focuses on issues related to the structural and mechanical degradation of steel as a material for parts of mining machinery. In this paper, a methodology for evaluating the degree of structural degradation of three types of bucket wheel excavators with different operating hours (ERc 1400-30/7-07 with 50,400 h, ERc 1400-30/7-08 with 69,264 h, and SRs 1300-26/3.5 with 112,000 h) is proposed. The methodology aims to provide a quantitative assessment of the structural degradation by considering the specific elastic limit of the material used in the machines and the number of hours of operation. This method uses a minimum set of destructive mechanical tests, such as tensile, resilience for three working temperatures, chemical analysis, and durometry on resistance elements taken from the machine, as well as the use of Weibull analysis. By combining this information with the number of hours of operation, a comprehensive evaluation can be made to determine the extent of degradation and potential maintenance requirements. The use of a minimum set of mechanical tests ensures an efficient and cost-effective approach to assessing the structural integrity of these machines. The metallographic analysis highlighted a predominant and defined form of grain rearrangement in the E14-07 machine after only 50,400 h. The constituents identified in the samples taken from the three machines are ferrite and pearlite. The highest hardness of the samples was recorded for the E14-08 machine, with values between 162–165 HV10. For bucket wheel excavators E14-07 and E14-08, the material structure showed elongated grains in the direction of deformation, compared to the material structure of E13-04, which has finely equiaxed grains. As a result of the research, final conclusions were formulated. [ABSTRACT FROM AUTHOR]

With the widespread application of multi-axis machining in the industrial manufacturing, aerospace, and military equipment sectors, the demand for machining ultra-precision components has been steadily increasing. Contour errors directly impact the quality of machined parts. In conventional multi-axis motion control systems based on cross-coupling, it is conventionally assumed that all individual axes are of equal significance during machine processing. However, in practical machining scenarios, diverse machining trajectories and accuracy requirements give rise to distinct control necessities for each axis. This complication leads to challenges in ensuring a consistent single-plane contour, thereby constraining the elevation of the overall contour accuracy. To address this issue, this study proposes a multi-axis contour error suppression method based on composite hierarchical control. The approach advocated in this paper initially ensures the precision of single-axis position control through the development of an advanced S-shaped function-based sliding-mode disturbance observer. Building on this foundation, the three-dimensional spatial contour is segregated into upper and lower layers. Subsequently, dedicated fuzzy PID cross-coupling controllers are devised for each layer. The experimental outcomes substantiate that in comparison to conventional cross-coupling control methods, the method introduced in this study, rooted in composite hierarchical control, not only guarantees the accuracy of single-plane contours but also further enhances the overall contour precision. [ABSTRACT FROM AUTHOR]

Coaxial monitoring of the Direct Energy Deposition (DED) machines enables a real-time material deposition study. Coaxial-images contain substantial melt-pool information and incorporate situational information including the sparks' intensity, numbers, etc. Recent studies have shown that melt-pool observations correlate directly with machine parameters and artifact properties. Therefore, the melt-pool information not only can assist in measuring the machine's working condition and determining machine operation parameters' reliability but also facilitates the deposition characteristics studies like print's regime and dimensions. This information is gathered during the fabrication and can be expanded to perform various process studies and fault registration. This paper utilizes the Optomec DED machine to fabricate single-track prints with multiple process parameters, while a coaxial camera records the deposition. Each deposited track is then cut perpendicular to the print's direction to facilitate process parameters correlation study with actual geometrical deposition measured using a microscope. The coaxial images taken during fabrication, along with their process parameters, cross-cut measurements, and a developed image-processing toolbox, are presented alongside this paper to empower future research directions. [ABSTRACT FROM AUTHOR]

The contact parameters of joint interfaces have a great influence on the dynamic performance of the machine tool, and the dynamic performance determines the machining precision of the machine tool. Therefore, it is important to accurately identify the contact parameters of joint interfaces to improve the machining precision of the machine tool. In this paper, a method of identifying the joint interface stiffness parameters based on a joint simulation in Matlab and Ansys is first proposed, and then stiffness parameters of joint interfaces between the bed and column of the precision grinding machine are identified by applying the method. Finally, the feasibility and high efficiency of the proposed method are proved by comparing the natural frequencies of the simulation and the experiment. In order to further analyze the influence of joint contact parameters on the performance of the joint interfaces, the theoretical model of the normal stiffness of the joint interfaces based on fractal geometry is amended and verified by taking into account the asperity interaction and elastic–plastic deformation. Then, the modified model is extended to a three-dimensional model, which is more in line with the actual situation. Finally, the influencing factors of the joint interface stiffness are analyzed. The conclusions of this paper are of great significance in the dynamic performance analysis and structural design of machine tools. [ABSTRACT FROM AUTHOR]

Ni-based superalloys fall under the category of difficulty in machining type material owing to their poor thermal conductivity and high strength at extreme temperatures. Machining such materials using the traditional approach is a tremendously difficult task. On the other hand, EDM, one of the most sophisticated electro-thermal manufacturing processes, is used to machine such materials. It is a well-known non-traditional machining process for generating parts that require accuracy, have complex shapes, and are small in size. However, the use of EDM in Ni-based superalloys has some disadvantages like poor surface finish and low material removal rate. So, to alleviate these disadvantages, researchers introduced powder mixed dielectric fluid in the EDM process. Further, the performance of this technique has been enhanced by studying the effect of various nano/micro-size particles and their concentrations in the dielectric medium. In this paper, the authors have reviewed the impact of non-electrical and electrical process parameters on the output responses when machining Ni-based superalloys using powder mixed EDM. The challenges faced during the conventional machining of Ni-based superalloys and the mechanism proposed for powder mixed EDM, especially under the influence of suspended powders into the dielectric medium have also been presented in this paper. Finally, future research areas of powder mixed EDM of Ni-based Superalloys, such as (i) its modelling and simulation and (ii) the effect of tool motion and powder properties on its performance, are discussed in brief. [ABSTRACT FROM AUTHOR]

This paper presents an Adaboost algorithm based cutting data analysis for chatter detection. This offline chatter analysis uses the vibration data collected by accelerometers attached to the spindle housing. A comparison of the accuracy achieved with support vector machine, Random Forest, 1D Convolutional Neural Networks and Multilayer Perceptron algorithm is also made. In this paper, the accelerometer data are transformed into bandwidth. Time-accelerometer and time-spectral bandwidth learning models are built in order to realize chatter detection and automated machine learning. A comparison of the models is made. The results of cross validation indicate that an accuracy of 98% is achieved, which is made possible by using the bandwidth signals that are transformed from accelerometer data. Experimental results show that applying the Adaboost algorithm to analyze the spectral data transformed from vibration signals and using them to detect chatters has higher reliability and accuracy compared to other algorithms and analyzing other transform signals. [ABSTRACT FROM AUTHOR]

High-speed mechanical drilling based on the micro-bit is the mainstream process technology for machining micro-holes in the printed circuit board (PCB). However, the above process to obtain PCB micro-holes is prone to defects, such as hole burrs and nail heads in the hole. In this paper, the micro electrical discharge machining (micro-EDM) was used as an auxiliary means for machining PCB micro-holes to effectively eliminate the defects such as hole burrs and nail heads. However, during the process of micro-EDM, the micro-bit will be gradually worn, thus negatively affecting the machining quality of PCB micro-holes. To solve the above problems, in this paper, the temperature field model of micro-EDM-assisted machining of PCB micro-holes was established to predict the micro-bit wear by analyzing the temperature field with COMSOL Multiphysics software. This paper made an extensive study of the influences of spindle speed, machining voltage, and pulse width on temperature field and micro-bit wear. The simulation results show that with the increase in machining voltage and pulse width, the temperature of PCB micro-hole machining increases, resulting in an increase in micro-bit wear. The spindle rotation is beneficial to the updating of the machining medium and the discharge of heat generated from EDM. Therefore, with the increase in spindle speed, the temperature of PCB micro-hole machining and the micro-bit wear is reduced. [ABSTRACT FROM AUTHOR]

The article reports on the technique that was developed to produce three-dimensional computer models of forming fabrics. The technique consists of machining cross-sections of a fabric, imaging the cross-sections, and then reconstructing the fabric structure using computer-aided design (CAD). A demonstration of the application of this technique is presented which shows the existence of critical distances between filaments. An insight into the drainage flow through a fabric, which has an effect on the microstructure of paper produced on it is provided by this imaging technique.