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The complexity of composite grinding movement, the variety of machining features and available grinding wheels, and the changing working conditions pose a challenge to the rapid programming of safe and efficient composite grinding procedure. The procedure optimisation plays an important role in solving this difficult problem. Therefore, a procedure optimisation method is proposed for composite grinding based on a Digital Twin (DT) system, which takes procedure time as optimisation objective to achieve high efficiency and ensures process rationality and safety by constructing corresponding constraint conditions. Moreover, the actual working conditions mapped into the DT system, such as workpiece parameters, machining requirements, grinding wheel parameters and status, machine tool motion position, and so on, are obtained to update the parameters involved in the optimisation model. And thus, the proposed method has the ability to timely find the optimal procedure under changing working conditions. In addition, a combination algorithm based on genetic algorithm (GA) and dynamic programming is proposed, which greatly reduces the search space of GA and realises the two-class co-optimisation of grinding wheel selection and procedure. Finally, the case study verifies the effectiveness of the proposed method to reduce procedure time and the dynamic response ability to changing working conditions. [ABSTRACT FROM AUTHOR]

After grinding, the machine tool spindle with high surface integrity has a significant impact on its subsequent service life. Therefore, it is necessary to create a reasonable process plan for the grinding process of the machine tool spindle. A hybrid method based on case-based reasoning (CBR) and process reasoning (PR) was proposed in this paper. The subjective and objective weights of feature attributes are determined in the CBR by the AHP method and the CRITIC method, respectively, and the similarities between the latest case and the retrieved case are calculated on the basis of the nearest neighbour algorithm. The most suitable process solution can be selected from the case database by means of CBR. PR is applied to solve the problem that the case cannot be retrieved through CBR or is unsatisfactory. In the case of the grinding machine spindle, the applicability of this technology was demonstrated. Consequently, the results revealed that the surface consistency of the spindle after grinding was substantially increased. A decision-making system based on the proposed approach was developed by using Qt 4.8.7 and SQLite 3. The results demonstrate the viability and efficacy of the hybrid CBR-PR method to rapidly generate process planning for specific parts. [ABSTRACT FROM AUTHOR]

The production of non-circular thin optical lenses involves initial processes such as circular cutting, grinding, lapping, and polishing. However, shaping the lenses into non-circular forms requires a final cutting process. This study focuses on addressing the distortion of BK7 thin glass parts during side grinding. Two clamping methods were examined to fix the components. The first method, commonly used in the industry, involves bonding the workpiece to a base using resin and subsequent machining, followed by separating the samples from the base by heating the resin. In contrast, this research explores an alternative approach using vacuum clamping. The components' distortion was measured using an interferometer. The results show that the vacuum clamping method produces more uniform surface parameters for the polished components compared to the typical resin bonding method. Additionally, the analysis reveals that surface parameter variations are more pronounced during square side-grinding compared to circular side-grinding. [ABSTRACT FROM AUTHOR]

This study introduces a new method for efficient and low-damage machining of Ti6Al4V: laser-assisted CBN belt grinding. The impact of laser power and grinding depth on the machining behavior of the material is investigated, the elemental distribution and chemical state of the ground surface are analyzed, and the removal mechanism of laser-assisted CBN belt grinding is described. The results show that increasing laser power will improve processing efficiency, enhance plastic material removal, and improve surface quality; the tangential grinding force is decreased by 63.5% and the normal grinding force is decreased by 72.6% at the maximum laser power; a large amount of Ti and N are present on the ground surface, and they are present in the form of TiN compounds. This study is a guide to the research on efficient and low-damage machining of hard-to-process materials like titanium alloys. [ABSTRACT FROM AUTHOR]

The ball-end milling cutter is widely used in the machining of various complex curved surfaces and grooves. In order to meet the machining requirements of SiCp/Al, the mathematical model of ball end milling cutter, grinding track of grinding wheel and parameters in the actual machining process are optimized, and the experiment of milling SiCp/Al is designed. The results show that the surface roughness processed by the grinding tool is small. In the process of milling SiCp/Al, the main wear position of ball end milling cutter is the flank. [ABSTRACT FROM AUTHOR]

This paper attempts to introduce a design architecture for the contour mill-tool grinding. Due to the unexpected three-dimensional interference known as the undercut/overcut between the grind wheel and the contour mill-tool, the corresponding design needs to go through a complicated iterative process in order to obtain the path generation parameters to compromise the flute constraints at different cross-sections. Neural networks (NNK) in recent years have proven to be of great significance in decrypting nonlinear relationships, use of which greatly reduces the computation time from hours to minutes for the tool designer. The key to success is either using a database or the NNK result to reduce the computational burden in the conventional numerical iterations. The aim of this work is to develop an automated NNK search using reinforced adaptation to learn the domain where the undercut/overcut problem is needed to be compromised. Furthermore, a new neural architecture algorithm guarantees the model convergence and result precision. The grind wheel position and orientation are then converted into NC codes for a specific five-axis grinding machine to perform either the cutting simulation or manufacturing. The experiment on machining and design comparisons to the state-of-art software have been included in this paper. [ABSTRACT FROM AUTHOR]

Gears are among the most crucial components in the transmission systems of machine tools. Gear manufacturing includes a number of processing procedures. The grinding process is an important procedure involving high precision and fairly small grinding surfaces. For this reason, this study aimed at developing a quality assessment model for the internal cylindrical grinding process of gears. The Six Sigma quality indices (SSQIs) were used to directly assess the quality of the internal cylindrical grinding process due to their ability to directly reflect quality level and process yield. Since the process may include nominal-the-best (NTB), larger-the-better (LTB) and smaller-the-better (STB) quality characteristics, so we used the variable transformation method to normalise the specifications of each quality characteristic for the convenient and effective management and analysis of process performance for multiple quality characteristics. We then constructed a multi-characteristic process quality analysis chart (MPQAC) to simultaneously assess the quality levels of various quality characteristics. Furthermore, the MPQAC can provide references for process improvement. This ensures the quality of internal cylindrical grinding and enhances the quality of gear and machine tool products. Finally, a real-world application and numerical experiments demonstrate the effectiveness and practical applicability of the proposed method. [ABSTRACT FROM AUTHOR]

National reform documents and shifts in educational standards have continued to highlight the importance of engineering and engineering practices within science literacy. High-quality engineering opportunities must be present in formal education due to their association with problem-solving and critical thinking. Given this directive to reach students, education reform must also focus on in-service and pre-service teachers who will provide these opportunities to students. One way to investigate elementary teachers' understanding of engineering is to collect conceptual diagrams. We have leveraged construct-centered design to develop and empirically ground a tool focused on engineering education: Draw-An-Engineering-Teacher-Test (DAETT). This instrument provides pre-service teachers and elementary educators the opportunity to capture pre/in-service teachers' mental images and reflect on what they believe engineering would and could look like in the classrooms. This project documents the piloting, development, and validation (K =.87; 95% CI =.742 to.989; p <.005) of the DAETT to record pre-service teachers' conceptualizations around engineering education. [ABSTRACT FROM AUTHOR]

An integrated polishing and in-situ measurement machine tool with seven-axis and five-linkage is developed for manufacturing and measuring the complex curved surface such as blisk. Firstly, this paper introduces the structure and configuration of the machine tool. Then, the kinematic analyses of the polishing side and measuring side of the machine tool are carried out respectively and the inverse kinematic solutions of them are derived. The motion of each axis can be calculated based on the tool location of the complex curved surface through the inverse kinematic solution. Aiming at the in-situ measurement of parts with complex curved surfaces, the forward kinematic solution, the processing of measured data of blade surface and the calculation algorithm of the machining allowance are developed in the paper. Finally, the above algorithms are verified by polishing the experimental stainless-steel sample. [ABSTRACT FROM AUTHOR]

It is known that there are some grinding issues for difficult-to-machine materials, such as adhesion of the grinding wheel, grinding burns, and poor surface quality. In this work, a novel abrasive tool which was based on the principle of liquid body armor was developed with flexible composite to improve the grinding performance. During grinding, particles in the abrasive tool will produce a "hydro-cluster effects" to remove the micro convex of the workpiece surface in a high-shear and low-pressure manner. Rheological measurement of prepared shear thickening fluid (STF) and shear thickening abrasive fluid (STAF) showed that the prepared STF and STAF possessed superior shear thickening properties. In addition, the grinding experiments were carried out to investigate the performance of the novel abrasive tool. Surface roughness of the Inconel718 workpiece decreased from Ra 1.55 μm to Ra 0.38 μm within 90 min. The original pretreatment marks were completely eliminated and the better surface finish was achieved. The surface quality of Inconel718 was greatly improved after grinding. Experimental results verified the effectiveness of the novel high-shear and low-pressure abrasive tool. This work is quite potential to provide an alternative new abrasive tool for the grinding of difficult-to-machine materials in manufacturing industries. [ABSTRACT FROM AUTHOR]

This paper presents an error identification method for directly related geometric errors of 4-axis forming grinding machine tool and some processing-induced errors from actual teeth profiles of a machined cycloid gear. Based on the developed 4-axis geometric error model, we build up an overall error model of cycloid gear-tooth profiles by forming grinding, which includes some directly related geometric errors of the machine tool and processing-induced errors. Error separation or identification methods are developed in correspondence with the form grinding process and are verified by some non-cutting identification or measurement techniques, including multi-lateration laser measurement technique and a laser rotary axis calibrator. The experiment results demonstrate that the separated geometric errors based on the machining test approach reach a better accuracy. In order to further improve the machining accuracy of the cycloid gear, two identified geometric errors and tooth-shaped error can be utilised for error compensation in the future. [ABSTRACT FROM AUTHOR]

The paper presents the current development of the Generalized Intelligent Grinding Advisory System (GIGAS), which provides a systematic way of modelling complex grinding processes and finding optimal process conditions while meeting the general class of process requirements. GIGAS provides a way of incorporating three different types of knowledge, including analytical models, experimental data and heuristic knowledge from experts, to describe complex grinding processes. The developed optimization algorithm can handle various optimization problems including different grinding processes and optimization objectives. Case studies are presented for surface grinding and cylindrical plunge-grinding with various optimization objectives to demonstrate its capability of performing optimization. The overall architecture and the developed software with the graphical user interface are described. [ABSTRACT FROM AUTHOR]

CNC grinding machines are widely used to obtain a good surface finish and tight tolerances. However, these machines are expensive, therefore manufacturers are considering adding a grinding spindle, interchangeable with a boring bar, to a turning lathe. To facilitate this, complex software is required because the programmer must control the whole surface of the grinding wheel not just the tool or cutter tip, as in turning or milling. This paper presents a general algorithm to simplify the grinding programme. The programmer will use this algorithm to create a subroutine suitable for the machine. The subroutine may then be used for all grinding operations. The programmer will need only to describe the contour of each workpiece, as for a CNC lathe program, in a separate small program. The algorithm has been applied to a hollow spindle lathe equipped with Sinumeric 840 C numerical control, and several gun barrels were turned and ground using the proposed approach. Satisfactory results were obtained. [ABSTRACT FROM AUTHOR]

Development in production technology has increased the need for high productive efficiency and effective utilization of machines. Tires, paper, rexin, and other rubber-based products are produced by using calendar roll machines. Web wrinkling, torn material, misaligned cutting, slitting, poor adhesion and laminate characteristics are the major errors in a calendar roll machine. The geometry, camber of rollers play a major role for most of the errors stated. This paper focuses on the experimental investigations carried out for cambering the rolls in-site (without removing), through grinding process with newly modeled equipment. The results obtained through in-site grinding are compared and discussed. It is observed that in-site grinding reduces the machine idle time by three-fourth of the normal roll grinding process and avoids the machine characteristic errors. New equipment comfortably eliminates the wrinkles and improves the quality of the rubber-coated fabric with the variation in thickness only between 1 and 2 µm. [ABSTRACT FROM AUTHOR]

The design of a grinding process is a difficult task since there are so many characteristics to consider. In this study, a generic scheme to establish the norm for automation of design by employing fuzzy logic and neural networks for a surface grinding process is proposed. Design of a grinding process is accomplished by initial determination of a set of optimal design variables in order to achieve a set of desired process variables. First, the important features of a surface grinding process are identified. Next, advisory systems for surface grinding design are reviewed. After that, a 'fuzzy grinding optimizer' (FGO) and a 'neural grinding optimizer' (NGO) are proposed. In addition, a generic scheme called 'bi-directional construction of fuzzy and neural systems' (BCFNS) is proposed for performance evaluation and comparison between fuzzy logic and neural networks. Finally, future research directions are pointed out concerning performance evaluation for various types of grinding optimizers. [ABSTRACT FROM AUTHOR]

In cylindrical plunge grinding, a series of workpieces are ground successively without intermediate dressing of the wheel. Through the grinding, the wheel characteristic is continuously changed by the wear, fracture and new exposure of abrasive grains, having a profound effect on the grains on wheel surfaces in the cylindrical grinding process are developed to make it possible to describe the time dependent results of grinding and to establish the grinding operation standards capable of estimating grinding wheel performance and selecting grinding conditions, in which many parameters in actual grinding operations are considered. This simulation system can display its results in graphical form including the time dependent results and the effects of various parameters as well as optimization capabilities. This simulation has the same effects as many grinding experiments, and capable of selecting the optimum grinding wheels and conditions. [ABSTRACT FROM AUTHOR]

Plunge grinding, like other grinding operations, is a complex process because of a large number of factors that are involved. This often makes it difficult to determine the optimal grinding parameters in pursuit of a certain product quality and cost, based upon the existing generic knowledge and experience about the process. However, the combined effect of the large number of factors and therefore, the performance characteristics of a given grinding system (including grinding wheel, component, grinding machine as well as workpiece holding system) can be learned by monitoring the grinding process. This can then help in the determination of optimal or near optimal grinding parameters. The paper describes a computerised system for the analysis of a plunge grinding operation based on the monitored power traces. This analysis yields data on important parameters such as grinding power (P), specific energy (E[sub s]), grinding force (F[sub 1]) system deflection (ΔY) and stiffness (K[sub s]). The paper also discusses the evaluation models used in the system, in particular, the model proposed for evaluation of system deflection and stiffness. The effect of the system stiffness on grinding process is analysed and a method to determine spark-out period, required to eliminate the system deflection, is proposed in the paper. [ABSTRACT FROM AUTHOR]

In this paper, the effectiveness of some approaches to on-line supervision of the grinding process is discussed. The advantages and corresponding shortcomings of some indirect methods previously recommended are compared. The authors recommend the information distance measure as a new criterion for distinguishing the different stages of the grinding process. Experiments have verified the advantages of this criterion in the terms of its efficiency, reliability, adaptability, computer storage saving and simplicity of instrumentation. [ABSTRACT FROM AUTHOR]

This article presents the procedure of optimization of the creep-feed grinding process and gives results of testing and optimizing the grinding of Nimonic 80 A material. The tests have determined the relations of grinding forces in relation to grinding conditions applicable to various methods of dressing the cutting surface of a high-porosity grinding wheel. The dressing of a grinding-wheel cutting surface has been carried out using the dressing and crushing rollers. By preliminary tests the marginal values of the equivalent grinding thickness have been established at rough grinding for the quoted methods of dressing the cutting surface of a grinding wheel. A permissible roughness of a ground surface has been taken as a limiting value for fine grinding. The function-aim of optimization has been set as the relation of the specific metal removal rate and the specific thrust grinding force tending to its maximum value. Thereby maximum feasible productivity and the most favourable conditions of the grinding forces expressed as the minimum-thrust grinding force have been taken into consideration. [ABSTRACT FROM AUTHOR]

The three grinding processes, namely, surface, internal and external are simulated using a specially designed computer program. The grinding wheel cutting profile is generated randomly using probabilistic techniques. For the three grinding process modes the conformity of the wheel work is analyzed for the same input parameters. Based on the findings, proper input parameters can be selected for achieving a given product quality. [ABSTRACT FROM AUTHOR]

This paper deals with an investigation undertaken for the purpose of determining the requirements of a measuring system capable of monitoring, on-line, the workpiece geometry on a cylindrical grinding machine. Results of a typical test are presented under the categories of three components of geometrical error, i.e. out of roundness, waviness and surface roughness. [ABSTRACT FROM AUTHOR]

Grinding aids (GAs) effectively reduce the energy requirements of the grinding process and improve grinding productivity. Two GAs (sodium silicate and triethanolamine (TEA)) were selected and their mechanisms of action were explored. The effect of the different grinding parameters on oil shale grinding efficiency was determined. The adsorption characteristics of the GAs were investigated using scanning electron microscopy (SEM), pulp viscosity, surface potential, and Fourier transform infra-red spectroscopy (FTIR). The results indicate that compared to grinding without GAs, the addition of sodium silicate and triethanolamine (TEA), increases the yield of −0.075 mm particles by −2.97% and 14.05%, respectively. The optimal grinding parameters were determined for a pulp concentration 40%, a steel ball weight ratio of Φ32 mm: Φ25 mm: Φ22 mm: Φ18 mm (50:24:17:9), and a grinding time of 20 min. The flotation test results indicate that compared to sodium silicate, TEA is the more suitable GA. The addition of sodium silicate reduced the sharp edges of the particles, increased the pulp viscosity and reduced the surface potential. It was not conducive to pulp dispersion. Conversely, TEA reduced the pulp viscosity and increased the surface potential, which enhanced the repulsive force between the particles, increasing the particle spacing, and the dispersion of the pulp. Sodium silicate and TEA both formed hydrogen bonds or chemical bonds on the surface of the mineral particles, strengthened the steric-hinderance effect, and enhanced the repulsive force between the particles. [ABSTRACT FROM AUTHOR]

In the fabrication and maintenance of hydroelectric turbines, the reconstruction by grinding of certain high-curvature surfaces such as junctions has not yet been robotized and must now be done manually. The problem is related to the very fast grinding wheel wear and the difficulty in controlling the position and orientation of the robot's grinder to adjust to changes in wheel shape. If the grinding wheel orientation is kept constant with respect to the workpiece, wheel-workpiece conformity increases, specific energy increases, the material removal rate drops and glazing of the wheel may occur. This article presents a method for controlling simultaneously the profile of both the workpiece and the grinding wheel. The orientation of the wheel is oscillated to maintain a constant wheel profile throughout its life and thus achieve better control in material removal. Research results provide the basis for robotic grinding tool profiling. [ABSTRACT FROM AUTHOR]

It is well known that fine particles have a negative influence on the energy size reduction of other materials in the grinding chamber. But a quantitative evaluation about it is relatively less. In this article, a Hardgrove mill was used to investigate the effect of fine coal on the grinding energy, specific rate of breakage of the top size, and the production of fine coal in -0.074 mm size fraction. A qualitative description of the friction coefficient between coal and grinding media demonstrates that this index drops with more fines added in the particle bed. The decreasing degree of grinding energy increases 2.5 times if added level of fine coal changes from 2.5 g to 10 g. Breakage of the top size at different added levels of fine coal still follows the first-order law. But due to the decrease of grinding energy and the cushion effect of added fine coal, the breakage rate of coarse particles decreases 2% to 25% if compared with the single breakage. Decreases of grinding energy and breakage rate finally result in a lower yield of fines (-0.074 mm). Hence, added fines decrease the grinding energy efficiency and make the breakage time consuming. [ABSTRACT FROM AUTHOR]

An empirical relationship of the Hardgrove Grindability Index (HGI) was established in terms of breakage parameters. In order to model particle-breakage behavior in a crusher, breakage parameters and HGI of material should be taken into consideration. Coal grindability has long been studied and empirical equations evaluating coal characteristics data have been proposed. Basically knowing the size distribution of the feed coal to the crusher and obtaining an experimental product size distribution after processing could help to model the operation conditions of the device. Breakage processes for coal have been modelled namely as π-breakage process, π, κ-breakage process and π, κ, ω-breakage process (π: proportion selected for breakage in an assembly, κ: number of breakage in a breakage operation ω: coefficient of size dependence). Having evaluated the breakage model for any crusher, the size distribution of crushed coal and its HGI could be related to each other. An empirical method between HGI and p proposed in this study was in good agreement with the experimental results. Experimental analysis of the crusher feed coal yielded an average HGI of 66 and the predicted HGI values were in the range of ± 10% of this average by employing the proposed method. As a second contribution of the proposed method, the stabilization of the size distribution of the crushed coal can be achieved with a decision mechanism for the plant operators about communition process. [ABSTRACT FROM AUTHOR]

With the increasing complexity of mechatronic products, traditional empirical or step-by-step design methods are facing great challenges with various factors and different stages having become inevitably coupled during the design process. Management of massive information or big data, as well as the efficient operation of information flow, is deeply involved in the process of coupled design. Designers have to address increased sophisticated situations when coupled optimisation is also engaged. Aiming at overcoming these difficulties involved in conducting the design of the spindle box system of ultra-precision optical grinding machine, this paper proposed a coupled optimisation design method based on state-space analysis, with the design knowledge represented by ontologies and their semantic networks. An electromechanical coupled model integrating mechanical structure, control system and driving system of the motor is established, mainly concerning the stiffness matrix of hydrostatic bearings, ball screw nut and rolling guide sliders. The effectiveness and precision of the method are validated by the simulation results of the natural frequency and deformation of the spindle box when applying an impact force to the grinding wheel. [ABSTRACT FROM AUTHOR]

Bone fragments are essential structures for the detection of processed animal proteins (PAPs) in feed by light microscopy for official controls according to Annex VI of European Union Regulation EC/152/2009. The preparation of samples submitted for analysis requires a grinding step to make them suitable for microscopic slide preparation and observation. However, there are no technical guidelines set down for this step despite the fact that it can lead to an increase in bone numbers due to fragmentation. This was demonstrated by an in-house study carried out by the Irish National Reference Laboratory (NRL) for animal protein detection. The present collaborative study investigated the possible effects of three different grinding conditions on the final result for a feed adulterated with 0.05 and 0.01% (w/w) of PAP. The microscopic analysis either combined or not with an Alizarin Red staining was carried out by 10 different laboratories. The results demonstrated that although a large variation in the numbers of bone fragments was noted, five of the six different grinding/staining combinations applied at two levels of PAP adulteration did not significantly (atp= 0.05) differ from one another. The only exception occurred when grinding the feed containing 0.05% of PAP with a rotor mill equipped with a 0.5-mm sieve and combined with a staining which resulted in a greater number of bone fragments by forced fragmentation. Overall, the impact of the grinding/staining combinations on the final results was shown to be negligible when considering the regulatory limit of detection (LOD) requirement for the method and the current rules of implementation of the light microscopic method. From a total of 180 analyses carried out on the feed matrix containing 0.05% of PAP no false-negative result was observed, and at a level of 0.01% PAP only 10 false-negative results occurred. [ABSTRACT FROM PUBLISHER]

Successful control of Semi-Autogenous Grinding (SAG) mill circuits has been the subject of many researches and main concern of plant operators for years. Distributed Control Systems (DCS) have had some degree of success in the mineral processing circuits, but maintaining operation of a SAG mill on the “edge” of its full capacity is not easily achievable by DCS. Advanced control systems, however, are a relatively new opportunity to successful control of mineral processing plants. This article presents the basis of a supervisory fuzzy expert controller for SAG mill circuits. Although leading companies in control and automation have their own commercial packages, this supervisory controller is coded in Matlab using Mamdani method and is able to connect to plant lower level control system. In the proposed controller, fuzzy system calculates optimum set points to the plant DCS control loops, enabling them to change the manipulating parameters to reach the new set points. This controller was installed, tested and verified in a copper grinding circuit. Results showed 1.8% increase in mill throughput, 3% decrease in power draw and more stable feeding regime at the same time. [ABSTRACT FROM PUBLISHER]

Ventilation mill for grinding coal is one of the main steam power plants in the system that makes a significant effect on the level of energy efficiency with its work. The aim of this paper is to increase the energy efficiency of thermo power plant Kostolac B by reducing the problem of wear in ventilation mill for coal grinding. The idea of this research is to investigate the optimum hardfacing technologies to increase wear resistance of impact plates in ventilation mill. Before applying hardfacing on impact plates in the exploitation conditions, it is necessary to model test hardfaced samples for determination of the optimal technology and filler material for revitalization. The relative weight loss of the impact plates after 1440 h period of exploitation in real conditions is very small, 5–8%. The application of this approach can reduce the number of possible repairs and extends the period between them, resulting in significant economic effects. Before and after revitalization of ventilation mill is conducted analyzing of failure during the working period. In this paper, we present time of repair of ventilation mills number 22, 23, 24 and 25, the number of repairs before and after revitalization and cost of repairs. [ABSTRACT FROM PUBLISHER]

Studies on the applicability of various configurations of Electrical Discharge Diamond Grinding (EDDG) are facing many challenges during the machining of advance difficult-to-machine materials. In the present paper, description of a new configuration of EDDG, called the Electrical Discharge Diamond Face Surface Grinding (EDDFSG) system, has been discussed. Experimental investigations have been made using the one parameter at a time (OPAT) approach to study the effect of gap current, on-time, off-time, abrasive grit number, RPM of wheel and table speed on the material removal rate (MRR) and surface roughness (Ra) during EDDFSG of hybrid metal matrix composite (MMC). Surface texture and recast layers of the machined surface have also been studied using Scanning Electron Microscopy (SEM). HigherMRRwith better surface finish and hardly seen recast layers on the machined surface demonstrate the potential applicability of the process for machining flat surfaces made of such challenging and complex materials. [ABSTRACT FROM AUTHOR]

Moving toward a hybrid approach, a hybrid process, electric discharge hole grinding (EDHG) was used to machine a hybrid metal matrix composite (MMC) (Al6063/SiC/Al2O3/Gr). Here, holes were drilled and ground in a single step process (EDHG) using a novel tool electrode. The experiments were designed using response surface methodology (RSM). The objective of this study was to investigate the effect of electric discharge diamond hole grinding operation on the surface roughness (SR) of the hole. The input process parameters were current, duty factor, tool speed and flushing pressure. It was found that the process is very effective in producing a finished hole. A comparison of surface roughness was made between electric discharge drilling (EDD) and electric discharge diamond hole grinding, thereby showing the effectiveness of the electric discharge diamond hole grinding process. The grinding action of the process is clearly visible in the scanning electron microscopic (SEM) image. It was observed that the craters, globules of resolidified material and micro cracks, which are normally seen on surfaces machined by electric discharge machining (EDM), are completely ground off by electric discharge diamond hole grinding. [ABSTRACT FROM AUTHOR]

Fine polyamide 66 (PA66) powder was prepared in a shear pan mill that was designed and developed in our laboratories. In contrast with discontinuous impacts in the ball mill, the size reduction operation in the pan mill is characterized by application of uninterrupted strong shear forces on particles. It has been found that as compared to the ball mill, much finer pulverization of the polymer material is achieved in the pan mill, in spite of the high strength and ductility of the polymer. Sodium sulfate ionic crystals with hard and pointed edge were co-milled with PA66 to further cut the fine polymer particles into ultrafine powder (2–5 µm). Besides acting as a grinding aid, the ionic crystals also prevented conglutination and aggregation of the polymer powder. Furthermore, PA66 powder could be conveniently separated and purified from the co-milled grinding aid-polymer mixture by simple water washing and filtration. Thus, an energy efficient and environment-friendly technology has been developed to prepare the ultrafine plastic powder at room temperature. This process holds a good promise for commercial applications. [ABSTRACT FROM AUTHOR]

Despite the rapid development of computer science and information technology, an efficient human–machine integrated enterprise information system for designing complex mechatronic products is still not fully accomplished, partly because of the inharmonious communication among collaborators. Therefore, one challenge in human–machine integration is how to establish an appropriate knowledge management (KM) model to support integration and sharing of heterogeneous product knowledge. Aiming at the diversity of design knowledge, this article proposes an ontology-based model to reach an unambiguous and normative representation of knowledge. First, an ontology-based human–machine integrated design framework is described, then corresponding ontologies and sub-ontologies are established according to different purposes and scopes. Second, a similarity calculation-based ontology integration method composed of ontology mapping and ontology merging is introduced. The ontology searching-based knowledge sharing method is then developed. Finally, a case of human–machine integrated design of a large ultra-precision grinding machine is used to demonstrate the effectiveness of the method. [ABSTRACT FROM AUTHOR]

To simulate the grinding process in an industrial vertical spindle mill, the Hardgrove mill was fitted with a power-measuring meter to investigate the breakage characterizations of different narrow size fractions of coal. Power consumption in the grinding process was precisely recorded at the sampling frequency of 1 second with the help of sampling software for power. The experimental results indicated that the energy input for grinding decreased with increases in time for each sample. Changes in the weight percentage in the top-size interval showed that the first-order law was not satisfied to describe the total grinding process. The new produced fine coal had a negative effect on the breakage behavior of coarse particles. But removal of −0.09 mm size can help to increase the energy input for grinding and the generating rate of −0.09 mm also accelerated in turn. The relationship between t10and energy input can be described by the classical breakage function. Specific energy consumed by raw coal with a small size was higher when subjected to the same value of t10, due to the relatively higher specific surface area of ground coal at the same breakage ratio of 10. [ABSTRACT FROM AUTHOR]

Silicon nitride ceramics are extremely difficult and time-consuming to machine with conventional methods, such as turning and grinding. Laser-assisted machining has been a field of extensive research during the past decade, as it is a promising solution to enhance the machinability of many difficult-to-cut materials, including silicon nitride ceramics. To enhance the processing precision of silicon nitride ceramic grinding, this paper presents an experimental investigation of a two-stage laser-induced wet grinding (LIWG) process, including laser-induced thermal cracking and wet grinding. Specifically, the differences in the grinding force, grinding force ratio and surface roughness obtained for LIWG and conventional grinding (CG) conditions are compared and discussed. The normal and tangential grinding forces for LIWG condition were lower than for the CG condition with a maximum reduction of 70.4% (83.3%) for the maximum average normal (tangential) grinding forces. The values of the force ratio for the CG condition and LIWG condition were in the range of 3.7–5.5 and 6.5–11.5. Little improvement was achieved, and the surface roughness values are considerable for both conditions. [ABSTRACT FROM AUTHOR]

Grinding characteristics of soy and red gram were compared employing single- and two-stage grinding in a mixer grinder. The initial size as well as hardness of soy (˜216 N) and red gram (˜220 N) were nearly equal. However, final particle size of red gram (61 μm) was much lower than soy (255 μm), indicating that red gram was relatively easier to grind. Analysis of microstructure indicated that typical internal structure and intercellular forces could play a significant role in determining the grinding characteristics of individual grains. With the same amount of energy input (200 kJ/kg), size reduction ratio in soy increased from 12 to 16 during two-stage grinding. Energy and particle analyses revealed that a two-stage segregated grinding is suitable for soy while a single-stage grinding is adequate for red gram. Classical dry grinding laws were applicable after initial break up suggesting their suitability for secondary grinding of soy and red gram. [ABSTRACT FROM PUBLISHER]

In this article, effects of moisture content and coal mixtures on grinding properties of the samples of two different fine coals, which were used in the Göltaş Cement Factory in Isparta (Turkey) were investigated. Grinding tests were done in a new grinder called “Mortar Grinder.” A good calibration has been established between the Mortar Grinder with the Bond and the Hardgrove grindabilities at the beginning of the tests. At the first stage, A and B type two coal samples, and in the second stage, the samples of three different mixtures (25% of A + 75% of B, 50% of A + 50% of B, and 75% of A + 25% of B) have been worked in grindability tests for different moisture contents. As a result, although the A and B coal samples were showing different grinding intervals versus moisture contents, these samples had similar grinding characteristic curves. Additionally, the high quality coals have easier grinding in respect to the low quality coals with the same moisture content. [ABSTRACT FROM PUBLISHER]

This article investigates an optimisation strategy for the design of rail-grinding profiles to be used on heavy-haul railway curves, aiming to reduce the rail side wear on curves. A design methodology of rail asymmetric-grinding profiles is put forward based on the principle of low wheel-rail dynamic interaction. The implementing procedure is illustrated in detail. As a case study, the rail asymmetric-grinding profiles were designed for a curve with 600 m radius on Chinese Shuohuang heavy-haul railway. The characteristics of wheel-rail contact geometry and wheel-rail dynamic interaction were analysed and compared between the original standard rail profiles and the designed rail-grinding profiles. The rails on a test curve were ground according to the designed profiles. Before and after rail grinding, both the wheel-rail dynamics indexes and the rail side wear were measured in the field. The theoretical and experimental results show that the wheel-rail dynamic interaction is clearly improved and the rail side wear is alleviated by 30-40% after rail grinding, which validates the effectiveness of the design methodology of rail asymmetric-grinding profiles on curves. [ABSTRACT FROM AUTHOR]

The ceramic materials are widely used in various industrial applications nowadays as they possess excellent properties like high hardness, low fractural strength, and brittleness, which makes machining very difficult and costly. Therefore, in the present work, the processes like conventional diamond grinding, electric discharge machining (EDM), and electric discharge grinding (EDG) are compared on the basis of material removal rate (MRR) and surface finish (Ra). EDG is the hybrid process of EDM and grinding and hence utilizes the benefits of both processes to give better MRR and surface finish than the parent processes. The MRR achieved in the EDG process is up to 50 times higher, and the surface roughness is at least 4 times better than the EDM process. The surface finish obtained by the EDG process is at least 4.5 times better than the conventional diamond grinding process and 3 times lower than cryogenically cooled conventional diamond grinding process. Surface and subsurface cracks, pit formation, and micropores were observed after conventional diamond grinding and EDM, but no such drawbacks were found on the selection of proper process parameters in case of the EDG process. Hence, surface finish and MRR obtained in EDG are better than EDM and the conventional diamond grinding process. [ABSTRACT FROM PUBLISHER]

A comprehensive experimental study on the cutting force differences between rotary ultrasonic machining (RUM) and conventional diamond side grinding, drilling and face grinding is conducted on K9 glass. By analyzing the experimental results and the kinematics of diamond grits, it can be seen that the reasons for the cutting force differences between with and without ultrasonic vibration are not same for the three machining processes. The cutting force difference of conventional diamond side grinding and RUM can be explained by analyzing the trajectory of diamond grits, while the cutting force difference of conventional diamond drilling and RUM is mostly dependent upon the difficulty level of removing chips. As a transitive form, the cutting force difference between conventional diamond face grinding and RUM is affected by both the diamond grits' trajectory and the difficulty level for removing chips. In addition, it is also noticed that different cutting tools have different reduction percentages of cutting forces in RUM compared with conventional diamond grinding. The findings are helpful for researchers to have a further understanding in RUM. [ABSTRACT FROM PUBLISHER]

The article looks at the potential of grinding machine guards in preventing injuries through simple impact tests with standardized projectiles. The grinding machine guards are made based on Standard No. EN 13218:2002, which determines least wall thicknesses for guards. Results suggest that steel projectiles must be utilized to assess the safety of grinding machine guards.

The knowledge base of a fuzzy logic controller (FLC) encapsulates expert knowledge and consists of database (membership functions) and rule base of the controller. Optimization of both of these knowledge base components is critical to the performance of the controller and has traditionally been achieved through a process of trial and error. Such an approach is convenient for FLCs having low numbers of input variables; however for greater numbers of inputs, more formal methods of knowledge base optimization are required. Genetic algorithms (GAs) provide such a method to optimize the FLC parameters to be globally optimum. The FLC is optimized by GA for varying nonlinearity and set point in the plant. The proposed control algorithm was studied on the cement mill simulation model and with a real cement mill model using MATLAB and Simulink environments. Parameters of the simulation model were set up based on the actual cement mill characteristics. The performance of the proposed control technique is compared with various other control techniques. The results of the control study indicate that the proposed algorithm can fully prevent the mill from plugging and can control the cement mill circuit more effectively. [ABSTRACT FROM AUTHOR]

This article is in two parts describing the analysis and simulation of the disc dressing process and its effect on grinding performance. This part is concerned with the generation of the wheel surface by a diamond disc dresser. A new stochastic model of the prediction of wheel topography by diamond disc dresser is developed. It predicts the number of active grains per unit area and average slope of grains of the alumina grinding wheel. This model is based on the fracture of grits and it considers the kinematical influences of the disc dressing process on wheel surface. It is possible to analyze the effects of changing dressing parameters on the wheel topography. The topography that is generated from this model provides a basis for further prediction of the grinding performance. [ABSTRACT FROM AUTHOR]

This article is the second of two parts which analyze and simulate the disc dressing process and its effect on grinding performance. In the first part a new stochastic model of the prediction of wheel topography by diamond disc dresser was developed. It predicted the number of active cutting points per unit area and average slope of the asperities on an alumina grinding wheel. In the second part the effects of a disc dressing parameter which affect the wheel topography, specific energy, and workpiece surface roughness are evaluated. An upper bound analysis of a pyramidal indenter which moves on the workpiece is used for evaluation of the specific energy and modification of the grain tip. Modified grain tip was then used to predict the surface roughness of the ground workpiece. Dressing conditions with various speed ratios, cross feed rates and depths of dressing were investigated. In each case, the grinding forces and the surface roughness were experimentally measured, and then the effect of changing dressing parameters on the grinding performance was analyzed. [ABSTRACT FROM AUTHOR]

The present work deals with a single layer brazed type cBN grinding wheels, which have been developed in-house. Grits were actively brazed on the working surface of the wheels in a regularly distributed pattern so that it could perform grinding without loading. In general, such a wheel produces substantially high transverse roughness. This happens because of its low active grain density. A touch-dressing technique, developed in-house, has been successfully applied on these brazed wheels so that most of the grits did participate and the average roughness could be brought down to an acceptable magnitude. This work investigated the co-relation between the grit size and cumulative depth of dressing required to achieve an acceptable magnitude of transverse roughness. It was found that the required cumulative depth of dressing was dependent on the size of cBN grits. This paper also shows the effect of gradual touch-dressing on improvement of roughness of the surface ground by such new class of recently developed wheels. Experiments were conducted with microcrystalline cBN grits of three different sizes. [ABSTRACT FROM AUTHOR]

The objective of this research is to develop a new method of grinding process that can efficiently make concave profile of the worm thread smooth. The grinding is carried out using a wheel with curvature profile in the axial plane in the form of an arc of logarithmic spiral. The proposed method will provide maximum line of contact between the tool and the worm with minimum stress concentration at any point. The generating equation of the grinding tool profile and its arrangement with respect to the worm during thread grinding were determined. [ABSTRACT FROM AUTHOR]

Hidden Markov model (HMM) is well known for sequence modeling and has been used for condition monitoring. However, HMM-based clustering methods are developed only recently. This article proposes a HMM-based clustering method for monitoring the condition of grinding wheel used in grinding operations. The proposed method first extract features from signals based on discrete wavelet decomposition using a moving window approach. It then generates a distance (dissimilarity) matrix using HMM. Based on this distance matrix several hierarchical and partitioning-based clustering algorithms are applied to obtain clustering results. The proposed methodology was tested with feature sequences extracted from acoustic emission signals. The results show that clustering accuracy is dependent upon cutting condition. Higher material removal rate seems to produce more discriminatory signals/features than lower material removal rate. The effect of window size, wavelet decomposition level, wavelet basis, clustering algorithm, and data normalization were also studied. [ABSTRACT FROM AUTHOR]

This paper describes a force model for grinding with segmental wheels. Both experimental and analytical results show that average grinding force decreases and peak force increases using segmental wheels as compared to conventional wheels. Larger spaces between segments further reduce the average force and increase the peak force. The reduction in average force is due to the size effect whereby the specific energy decreases at higher instantaneous material removal rates. An investigation of surface roughness and wheel wear reveals that modest amounts of segmentation reduce average force without increasing surface roughness or wheel wear. [ABSTRACT FROM AUTHOR]

Most integrated circuits (IC) are fabricated using silicon wafers. The continuing shrinkage of the size of IC features has imposed more and more stringent requirements on the wafer flatness. Furthermore, wafer manufacturers are under constant pressure to reduce the wafer cost. The traditional lapping-based manufacturing method is unable to satisfy the ever-increasing demand for better flatness and lower cost. Previous experimental study of a grinding-based manufacturing method has shown that excellent site flatness can be obtained on ground wafers except for a few sites at the wafer center. One cause for the poor flatness at the wafer center is the central bumps on the ground wafers. As a follow-up, this paper investigates the generation mechanisms of the central bumps on ground wafers, and provides solutions to eliminate or reduce them. The understanding and knowledge gained through this study can also be applied to the manufacturing of other semiconductor wafers (such as germanium, gallium arsenide, and silicon carbide). [ABSTRACT FROM AUTHOR]

The final phase of cement production at Inland Cement Edmonton is the grinding of an intermediary product called clinker. Operating the grinding machinery, or "finishing mills," requires a great deal of electrical power, which constitutes one of Inland's most significant expenses. This paper discusses a solution that provides Inland Edmonton with a tool to improve the cost-effectiveness of the grinding by directing the finishing mills' schedules, based on a variety of criteria and constraints. The project incorporates issues such as multiple products, varying power rates throughout each day and month, inconsistent productivity rates, inventory capacities, uncertain demand, and other considerations. [ABSTRACT FROM AUTHOR]