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A grain-arranged grinding wheel refers to a grinding wheel where the position of abrasive particles on the wheel can be customized. In this paper, the processing quality of the grain-arranged grinding wheel in different grain arrangements, including rectangle, rhomboid, and oblique rectangle arrangement, respectively, is compared with that of conventional grinding wheel in the grinding of single-crystal silicon. Comparisons have also been made between arranged wheel in oblique rectangle arrangement and conventional wheel in terms of 2D- and 3D-machined surface morphology, surface roughness, and grinding force. By considering the effects of the material removal process, abrasive grain interactions, and grain arrangement parameters, a grinding force model is built for the grain-arranged grinding wheel. Through processing experiments with different grinding wheels, it is found that the grain arrangement has a great influence on the machined surface quality. Rational and orderly grain arrangement can improve the machined surface quality and machining stability, but the machined surface quality of a grain-arranged wheel is not always better than that of a conventional wheel. Specifically, the machined surface quality of arranged wheels in rectangle arrangement is always the worst, but the difference of machined surface quality of the other three kinds of grinding wheels is not significant at low feeding velocity. With the increase of feeding velocity, the machined surface quality of arranged wheel in oblique rectangle and rhomboid grain arrangement will gradually be better than that of the conventional wheel. In respect of grinding force, it is found that arranged wheel in oblique rectangle arrangement owns a smaller average force and a more stable momentary force than that of the conventional grinding wheel. For the grinding force model built in this paper, its effectiveness and accuracy were finally verified by experiments. [ABSTRACT FROM AUTHOR]

The surface topography of laser dressed diamond wheel is different from that of conventional methods, including grain uniformity, grain protrusion height, and grain state, all of which signally affect the wheel grinding performance. This paper focused on the influence of the topography of the laser dressed resin-bond diamond wheel on grinding performance. The resin-bond diamond wheel was dressed with different laser conditions, and the wheel topographies were observed. The cemented carbide workpieces were ground by the wheel with different topographies, while the grinding force and the surface roughness were measured to evaluate the grinding performance. In the comparative experiment, the difference between laser dressing with mechanical dressing was discussed. The results showed that the average laser power had the greatest effect on wheel surface topography and thus influenced the grinding performance. The appropriate laser dressing conditions were that the average laser power was 10 W, the pulse frequency was 100 kHz, and the spot overlapping ratio was 50% in this work. The diamond wheel had better grain integrity and could accurately control the protrusion height by the laser dressing process, while with the mechanical method, there were defects such as abrasion, fracture, and falling off. The laser dressing allowed for better wheel topography and grinding performance. [ABSTRACT FROM AUTHOR]

This paper proposes a topology modification method of generating gear grinding based on multi-axis linkage parameter optimization. In order to improve the accuracy of tooth flank modification in generating gear grinding and to reduce the transmission error of modified gear pair, a multi-objective optimization genetic algorithm is adopted to adjust machine movement. Firstly, according to the position and motion relationship among diamond wheel, worm wheel, and workpiece gear, the mathematical models of worm wheel dressing and generating gear grinding are established. The linkage relationships between motion axes are redefined to achieve topology modification. The radial feed F X 1 , tangential feed F Y 1 of worm wheel, and gear rotational angle φ g are defined as the fourth-order polynomial function of axial feed F Z 1 . Secondly, the transmission error model of modified gear is developed. And the polynomial coefficients of each axis are optimized with the objective of minimizing total tooth flank deviation and transmission error. Finally, the effectiveness of this method is verified by three numerical examples with different parameter groups. In addition, the diamond wheel and worm wheel used in the study are standard profile, which saves the cost of gear machining and improves the efficiency of production cycle. The research results could provide a theoretical reference for the improvement of generating gear grinding process. [ABSTRACT FROM AUTHOR]

The growing demand for current and future projects lacks materials development and their manufacturing process, mainly when they need to be used in inert applications, where no physical or chemical reaction can interact with the elements around them. In this context, ceramic materials have stood out in applications that demand high resistance to temperature and wear, such as engine components and in situations where greater stability and chemical compatibility are required, such as prostheses and medical components. However, the manufacture of ceramic components is expensive and slow, given that the traditional manufacturing procedure for ceramic components is based on sintering. This process limits productivity and does not provide the final component with the high dimensional and shape quality required in more specific applications. However, there is still a lack of studies on the large-scale manufacturing processes of these products, mainly related to their grinding. Therefore, it is crucial to study the best ways of processing materials that will soon be essential to the mechanical, electronic, and biological industries. Furthermore, studies about advanced ceramics have become increasingly indispensable, based on factors such as high added values due to the difficulty of manufacturing combined with the high environmental impact caused by this process. However, advanced ceramics are materials with difficult to machine because of their high hardness and fragility properties, becoming required manufacturing processes more complex, such as grinding. Therefore, this paper explored several conditions applied to advanced ceramic, approaching the main variables used by worldwide industries, being: surface roughness (Ra), roundness error, diametral wheel wear, G-ratio, grinding power, and analysis costs process. The grinding process used in the research was of kind plunge combined with a diamond wheel applied to four different feed rates: 0.25, 0.50, 0.75, and 1.00 mm/min, in which two systems by application of cutting fluid in the process were also used: flood and MQL lubri-refrigeration techniques, with a flow rate of 15 l/min and 100 ml/h, respectively. The results indicated that the final conditions were affected by the increase in feed rate for both situations. Nonetheless, they were superior to those when the flood technique was used. However, the cost analysis process indicated that the drastic reduction of the amount of cutting fluid applied by the MQL provides better economic conditions when compared to the flood application technique, becoming this technique viable for industry application. [ABSTRACT FROM AUTHOR]

Laser dressing of super-hard abrasive concave surface diamond wheels is a very promising technology to overcome the shortcomings of current dressing methods. However, the technology is still at a preliminary stage of research, due to inadequate research on dressing methods and dressing principles, which makes it difficult to effectively shape. In this paper, a novel method named laser deflection tangential dressing was proposed for profiling concave complex-concave surface diamond wheels. The profile error after the tangential dressing was analyzed, and the compensation method was developed. The effects of the laser deflection angle and energy on the accuracy of dressing bevel edge profiles were investigated, and the impacts of the deflection angle and the compensation radius on dressing arc profiles were studied. The experimental results illustrated that the method of the laser deflection tangential dressing effectively solved errors in the dressing process. The PV value of the bevel edge profile dressing accuracy could reach about 8 μm at a deflection angle of 1–1.5°. With a suitable deflection angle, the radius deviation of the circular dressing profile could reach 10 μm with the compensation radius of 0.04 mm (for convex arc radius of 0.25 mm), 0.03 mm (for concave arc radius of 0.2 mm), and 0.06 mm (0.5 mm for concave arc), respectively. The overall profile error of the complex-concave surface was around 25 μm, and the surface morphology was relatively ideal. The grinding testing results of graphite and aluminum oxide workpieces were nearly the same, and the surface roughness Ra were 0.543 μm and 0.508 μm, respectively. [ABSTRACT FROM AUTHOR]

Freeform surfaces including both the aspherical and prismatic concave/convex have been widely utilized in optical, electronical, and biomedical areas. Most recently, it is reported that grinding with structured wheels provides new possibility to generate patterns on hard and brittle materials. This paper reports the latest research progress on micro-grooving glass ceramic using laser structured diamond grinding wheels. A nanosecond pulse laser is firstly integrated into an ultra-precision machine tool and used for the in-line conditioning of super abrasive grinding wheels, i.e., truing, dressing, and profiling/texturing. Meanwhile, an offset compensation method, considering the shifting depth of focus (DoF) at different laser irradiation positions, is proposed to accurately generate various profiles on the periphery of the grinding wheels. Three types of patterns (riblets, grooves, and pillars) are successfully fabricated on the ceramic substrate using the laser textured grinding wheels. The results indicate that the integrated laser system offers high flexibility and accuracy in shaping super abrasive grinding wheels, and the grinding using textured grinding wheels provides a promising solution to generate functional microstructures on hard and brittle materials. [ABSTRACT FROM AUTHOR]

Carbon/Carbon (C/C)–SiC composite materials attained much attention due to its unique properties like immense thermal conductivity, high corrosion, and abrasive resistance. Few scholars have systematically studied the grinding machinability of 3D C/C–SiC composite material. In this paper, the grinding experiment of 3D C/C–SiC composite material was carried out with a resin-bonded diamond grinding wheel. The effect of machining conditions on the grinding force, micromorphology, surface quality, and residual stress was studied, and the material removal mechanism was analyzed in-depth aimed at the three typical fiber orientations. The result shows that the surface roughness of different fiber areas follows the order: 90° fiber > 0° fiber > Normal fiber. The fiber's orientation showed a significant effect on the mechanism of material removal. The residual thermal stress of C/C–SiC composite material increases from 32.25 to 207.43 MPa during the grinding process. Polishing the ground surface not only can remove the crack layer and residual stress layer but also can introduce residual compressive stress layer, which can effectively enhance the material strength. The 3D C/C–SiC composite material removal process is distinct from the composite material 2D C/C–SiC and the traditional brittle material. The main removal of C/C–SiC composite material is recognized as brittle fracture mode. Because of the different mechanical properties of carbon fiber, SiC matrix, and the pyrocarbon interface, the damage of material during grinding is asynchronous. The present work provides a comprehensive understanding for processing 3D C/C–SiC composite material parts with high quality. [ABSTRACT FROM AUTHOR]

Diamond wire sawing has gradually applied as the dominant way of silicon sawing in the photovoltaic and semiconductor industry. In this paper, a model of stiffness of wire web was established, and the corresponding test measure, process, and evaluation standard were proposed. Lack of stiffness of wire web could easily cause wire bow and further reduce the machining accuracy during diamond wire sawing. And the machining accuracy due to wire bow was analyzed. The special significance of this study is considered the stiffness of wire web to be the key index of multi-wire sawing performance. Through this method, the wire bow and the lack of cutting accuracy can be reasonably evaluated. As a result, wire lag and wire bow due to the loss of the stiffness of wire web could be minimized, as well as its influence on machining accuracy. Static stiffness matrices of wire web were presented to analyze the influence of the feed position and the number of wires forming the wire web on the stiffness of wire web. Moreover, a FEM model was established to find the influence factors such as wheel span, wheel diamond, and preset tension on the stiffness of wire web. [ABSTRACT FROM AUTHOR]

It is easy to obtain the near-polished grinding surface using fine-size grain diamond wheel (such as #2000, grain size 6.5 μm) and a small grinding depth. However, a relatively big-size wheel (such as #600, grain size 24 μm) is difficult to accomplish the near-polished grinding. Hence, this paper proposes a novel axis-feed grinding approach with the assistant of pure CeO2 atomizing liquid to obtain the near-polished grinding roughness using a relatively big-size grain diamond wheel and a large grinding depth. Firstly, the brittle-ductile axis-feed grinding modes and the roughness prediction model are briefly introduced. Secondly, the #600 diamond wheel is employed to perform the experiments of grinding fused glass with the proposed technology. Then, the brittle-ductile axis-feed grinding modes, the softened speed and softened depth of fused glass by the effectivity of pure CeO2 atomizing liquid, and the grinding roughness obtained with different feed speeds and grinding depths are investigated. It is shown that the ultra-precision grinding of fused glass can be realized using a relatively big-size grain diamond wheel and a large grinding depth, and the resulting morphology and roughness are mainly influenced by the feed speed. There exists the combined action of softening and polishing caused by pure CeO2 atomizing liquid. The feed speed that the ductile grinding happens increases about 6.57 times due to the increase of the brittle-ductile transition depth from 21 to 138 nm caused by the softened effect. The mean grinding roughness can reach 1.05 nm at the feed speed of 1 mm/min and the grinding depth of 5–20 μm. [ABSTRACT FROM AUTHOR]

Monitoring the state of grinding wheel is helpful for quality control and efficiency improvement of large-scale optics. Various process signals are always used for the evaluation of wheel's state. Acoustic emission (AE) is the most sensitive one to the interaction of tool and material. However, AE signals are stochastic and board-band. The difficulty of feature extraction seriously impacts the performance of data-driven models applied in AE-based monitoring. In this paper, linear discriminant analysis (LDA) is employed on frequency spectra of AE signals and a LDA-based monitoring method is proposed to monitor online the deterioration of wheel's state. LDA is one of the supervised clustering methods. Samples with different labels are projected into a low-dimensional feature space for maximizing the distinction between classes. During grinding process, AE samples are acquired on some nodes with a fix interval of material removal volume. Successively executing LDA on the growing sample dataset and the change of projection pattern can give a clear representation of the transformation of wheel's state. Experimental results show that different wear stages and self-sharpening of grinding wheel can be real time recognized during grinding process. [ABSTRACT FROM AUTHOR]

Owing to its excellent physical and chemical properties, such as high temperature resistance, corrosion resistance, and low density, optical glass is widely used in high-tech fields such as aviation, aerospace, and national defense; however, the grinding force during the processing of optical glass seriously affects the surface quality. Therefore, in the present paper, a mathematical model of the grinding force of diamond wheels with the ordered arrangement of abrasive grains on optical glass materials is established. The influences of the grinding wheel landform layout parameters and processing technology on the grinding force are discussed. The results of theoretical analysis and experimental research show that the ordered arrangement of abrasive grains can effectively reduce the grinding force. The values predicted by the model are in good agreement with the experimental results, indicating that the established mathematical model can provide theoretical guidance for the optimization of parameters in the processing process. [ABSTRACT FROM AUTHOR]

It is difficult to machine with high machining efficiency and surface integrity for SiCp/Al composite, especially for those with a high volume fraction of SiC. Here, we present monolayer brazed diamond grinding wheels that contain different micro-textures ablated by pulse laser. The dry grinding characteristics of SiCp/Al composites with 70 vol.% SiC using the wheels with different micro-textures were investigated. The influence of micro-textures on the grinding force, grinding temperature, and surface integrity was examined. The results indicated that micro-textures on diamond grits can induce cleavages and form more micro-cutting edges in grinding of SiCp/Al. The wheel contains both micro-grooves and micro-hole and owns the lowest grinding force, grinding temperature, and surface integrity. The micro-textured wheel produces smaller grinding chips and less fracture, crushing, and pull-out of SiC particle on the ground surface of SiCp/Al composites than other wheels. [ABSTRACT FROM AUTHOR]

The grinding process manufactures parts with geometric and dimensional precision and surface finish. During the procedure, material removal requires high energy and generates heat in the cutting zone. The grinding of advanced ceramics, such as alumina (Al2O3, 97% purity), is even more complex and economically expensive due to its mechanical properties. Thus, cooling and lubrication techniques are needed to control temperatures. The conventional flood technique is currently the most used, but it has a high environmental impact combined with unhealthy chemical agents in the cutting fluid. As a result, cutting fluids are the inputs that pose the most significant risks and damage to the environment and human health. Applying atomized and pressurized cutting fluid directly to the cutting zone has shown manufacturing potential compared to the conventional flood technique to solve these problems. Despite this, the minimum quantity of lubricant (MQL) technique does not provide good thermal dissipation compared to traditional methods, requiring the inclusion of auxiliary systems. In addition, one of these techniques deals with adding different proportions of water to the mixture, aiming to improve the heat transfer of the process and minimize the phenomenon of clogging the surface of the grinding wheel. Thus, this study analyzed the performance of a diamond grinding wheel in the advanced process of ceramic grinding using different proportions of cutting fluid applied to the MQL system, as follows: MQL + Pure (Pure—100% cutting fluid), MQL + 50% (50% cutting fluid and 50% water), MQL + 25% (25% cutting fluid and 75% water), and MQL + 15% (15% cutting fluid and 85% water) compared to the flood technique. Thus, surface roughness, soil surface topography by confocal microscopy analysis, roundness error, diametral grinding wheel wear, G-ratio, grinding cost analyses, and CO2 pollution analyses were evaluated. In addition, MQL applications revealed fewer pollutants. Furthermore, they were more economical application conditions from the grinding cost analysis, making them a great eco-friendly alternative for use in the industrial sector. [ABSTRACT FROM AUTHOR]

In many practical situations, it is important to evaluate the relationships between the factors that compose an industrial process and their effects on one or more response variables that are of interest to an enterprise. The main contribution of this present study is to propose a new conceptual hybrid framework based on the DMAIC (Define, Measure, Analyze, Improve, and Control) methodological structure, to optimize complex experimental problems with multiple responses. This procedure combines Response Surface Methodology, with the Desirability (D), Modified Desirability (MD), Compromise Programming (CP) functions, with Generalized Reduced Gradient (GRG) and Evolutionary Algorithms (EA). We made real application to a glass lamination process case study to describe how to use the proposed framework. The procedure allowed several configurations to be tested involving the D, MD and CP functions, adopting the GRD and EV, to optimize the studied industrial process. The best configuration was defined by a practical confirmation experiment and validated by company engineers and experts. As examples of the advantages of adopting the proposed framework in the glass lamination problems, the best solutions resulted in a 49.86% increase in grinding wheel shelf life, corresponding to a 927kg reduction of steel-use per year, and a 41.7% reduction in dressing stone consumption, saving 17,200 stones per year. [ABSTRACT FROM AUTHOR]

A grinding method of fused glass is proposed through the dry chemical modification of atmospheric pressure plasma. Before grinding, the surface of fused glass is chemically modified by atmospheric pressure plasma, then the grinding experiment is carried out without any coolant. The objective is to explore the grinding characteristics of the dry chemically modified grinding by atmospheric pressure plasma. First, the experiment on the dry chemical modification of fused glass was carried out with different parameters of atmospheric pressure plasma. Secondly, a #600 diamond wheel was used to perform the grinding experiment with and without modification. Then, the element content, morphologies, and nanoindentation test of the dry chemically modified surface were investigated with reference to the parameters of atmospheric pressure plasma. Finally, the grinding roughness and morphologies were investigated with reference to the modified degree. It is shown that the modified degree of fused glass is influenced by the flow rate of CF4 and the feed speed of plasma. The mechanical property of material changes with the change of the modified degree, which plays a great influence on grinding processing. The grinding roughness can reduce by 32.7% with modification than one without modification. Moreover, the grinding roughness and morphology are related to the modified degree of fused glass. It is confirmed that the grinding processing of fused glass may be improved through the dry chemical modification of atmospheric pressure plasma. [ABSTRACT FROM AUTHOR]

In the mirror surface grinding of fine ceramics with diamond grinding wheels, the truing/dressing of wheels must be frequently performed to maintain the shape accuracy and abrasive cutting-edge sharpness of the diamond grinding wheels to ensure a high processing efficiency and precision. For this purpose, a novel method is proposed for truing/dressing diamond grinding wheels in which a cup-shaped GC (Green silicon carbide) wheel is used as the truing/dressing tool and an ultrasonic vibration is applied axially to the diamond grinding wheel during truing/dressing. A truing/dressing device was designed and fabricated, and a series of experiments were conducted to systematically investigate the truing/dressing characteristics of metal–resin-bonded diamond grinding wheels. The following conclusions have been obtained. The truing/dressing force Fx is decreased with an increase of the ultrasonic amplitude. After truing/dressing, the performance of the grinding wheel has been significantly improved, including the improvement of shape accuracy and the increase in the number of effective abrasive particles per unit area with the assistance of ultrasonic vibrations during truing/dressing. Moreover, during truing/dressing, the introduction of the ultrasonic vibration reduced the abrasive grain cutting-edge apex angle, meaning that the sharpness of the grain cutting edge was improved by the ultrasonic vibrations. The truing/dressing ratio increased with an increase in the ultrasonic amplitude, leading to an extension of the servicing life of the cup-shaped GC wheel. Finally, a comparison of the performance of the grinding wheels trued/dressed with and without ultrasonic vibrations during the grinding of zirconia ceramics revealed that the grinding wheel trued/dressed with ultrasonic vibrations yielded an enhanced machined surface quality and lower grinding forces. [ABSTRACT FROM AUTHOR]

Laser ablation is a common process for most hard materials with a variety of advantages, such as high efficiency, low vibration, and low environmental impact. As such, an increasing number of researchers take advantage of this technique in carrying out the dressing process on grinding wheels containing super-hard abrasives. However, as there is a complex interaction between the laser beam and matrix, it is hard to remove materials from the grinding wheel in a controllable way. To fill this gap, the laser ablation depth and width change with various laser powers, feed rates, and duty cycles are investigated and analyzed in this study. An analytical model regarding the laser ablation process on non-metallic, inhomogeneous materials is performed. The limitations and applicability of the model are also analyzed. Based on the evaluation results and experimental data, corresponding predictive empirical models are established and experimentally validated. This study shows that both the ablation depth and width are increased with duty cycle and laser power but decreased with increased feed rate. Interestingly, the ablation results are not largely affected by feed rate when compared to duty cycle and laser power. The ablation depth has a narrow variability under a given laser power and has a relatively wide variability for a given feed rate. The ablation depth and width are affected more by changes in the duty cycle under higher laser power. At higher laser powers, the ablation depth has a wider range of variation with the duty cycle, while the ablation width varies little. Overall, the ablation law is predicted by the empirical model, which can assist in ablation parameter selection. Finally, an experimental application is used to validate the models, and RMSE 0.2867, Bias 0.0296, and Std.Res. 0.2588 are achieved, indicating the applicability of the prediction model. The presented work is anticipated to be not only meaningful in providing the ablation law for laser parameter selection for industrial production, but also helpful in providing an academic resource for the research field of non-metallic multi-material laser ablation. [ABSTRACT FROM AUTHOR]

Taking the specific geometry and gesture of the diamond grains into consideration, a novel simulation model to predict the machined surface topography in grinding of superalloy (GH4169) is presented, where the arrangements of abrasive grains and the plowing induced pile-up ridges are also integrated. Based on the designed surface topography of the grains arrayed brazed diamond wheels, the grinding wheel was firstly reconstructed according to the following factors of the abrasive grains, including the shape, dimension, protrusion height, attitude, and position. In accordance with the kinematics of the grains, the pile-up ridges corresponding to the real-time depth of cut were then achieved, and the superposition resulting from the interference of successive abrasive particles was thoroughly discussed to simulate the final ground topography accurately. Finally, the grinding experiments at the selected parameters were undertaken to verify the proposed model, where the measured and simulated surface topography and the surface statistics (Sa, Sq) were investigated and compared. The favorable accordance between the simulated and experimental results indicated the accuracy and the practicability of the proposed model for optimizing the grain arrangement in the diamond wheel design and improving the grinding surface uniformity. [ABSTRACT FROM AUTHOR]