Rough Grinding Research Articles

Effect of Lubricated Liquid Carbon Dioxide (LCO2 + MQL) on Grinding of AISI 4140 Steel

This paper investigates the potential of utilizing lubricated liquid carbon dioxide (LCO2 + MQL) as an alternative to conventional flood cooling in grinding operations. This approach could facilitate a transition towards fossil-free production, which is a significant challenge in industry. The alternative cooling–lubrication method relies on pre-mixed LCO2 and oil and a single-channel minimum quantity lubrication (MQL) delivery method, which has already demonstrated potential in machining with geometrically defined cutting edges. However, this method has been less explored in grinding. This study primarily evaluates the grindability of AISI 4140 steel, examining surface roughness, residual stresses, microhardness, grinding forces, and specific energy for different cooling–lubrication methods. The results indicate that LCO2 + MQL is capable of attaining surface roughness and microhardness that is comparable to that of conventional flood cooling, especially in the case of less aggressive, finish grinding. Nevertheless, the presence of higher tensile residual stresses in rough grinding suggests that the cooling capability may be insufficient. While the primary objective was to evaluate the technological viability of LCO2 + MQL in terms of grindability, a supplementary cost-effectiveness analysis (CEA) was also conducted to assess the economic feasibility of LCO2 + MQL in comparison to conventional flood cooling. The CEA showed that the costs of both the cooling–lubrication methods are very similar. In conclusion, this study offers insights into the technological and economic viability of LCO2 + MQL as a sustainable cooling–lubrication method for industrial grinding processes.

Application of thin slice technology of loose cuttings sample in early stage of experimental geology

Abstract Thin section of rock is a highly technical work in the laboratory, and its application in logging site and rock identification is helpful to solve geological problems quickly in the process of exploration drilling. The cuttings samples cover a variety of lithologies, including sandstone and volcanic rocks with significant diagenetic differences. Due to the special properties of the cuttings, such as loose, fear of water, moisture absorption, brittleness, large hardness differences, inconsistent particle size, and not easy to penetrate glue, the production process has been challenged. In the temperature and humid environment, the cuttings are very susceptible to delixing, especially in the cuttings with cleavage development, more cracks and poor diagenesis. After the sticking sheet is affected by vibration during rough grinding, it is easy to produce warping edge and warping Angle, which leads to the destruction of the original structure of the mineral. The previous production process cycle is long, the operation is relatively not convenient, especially in the grinding into the international standard 0.03mm thick pieces there are certain difficulties. Therefore, it is very important to improve and optimize the rock wafer technology. This will help improve the efficiency of the production of cuttings and reduce the likelihood of damage to mineral structures, which in turn can be used more effectively in exploration drilling sites and rock identification, providing faster and more accurate support for solving geological problems. The results of this study have important significance for improving the efficiency and convenience of the production process and improving the application prospect of the rock sheet technology.

ПРИМЕНЕНИЕ КОМПЛЕКСНОГО ИМПРЕГНИРОВАНИЯ АБРАЗИВНОГО ИНСТРУМЕНТА ДЛЯ ПОВЫШЕНИЯ ЕГО ЭФФЕКТИВНОСТИ

The article discusses studies of the properties of impregnated grinding wheels. Based on the experiments carried out, a complex impregnator was obtained that combines initial and lubricating properties. The article discusses studies of the performance properties of impregnated grinding wheels. Based on the experiments carried out, a complex impregnator was obtained, which combines high reactivity and lubricity. The concentration of the components molybdenum disulfide, paraffin, hexachloroparaxylene and toluene was selected. The results of surface roughness grinding show a significant decrease in the Ra parameter and an increase in the grinding coefficient when using a complex impregnator.

Prediction model of grinding roughness for worm with complicated space tooth surface

Optimum grinding parameters are crucial for achieving high-quality grinding of helical tooth surfaces for worm drives. The complex coupling motion relationship and formation mechanism between the worm blank and the grinding head make it difficult to predict the effect of grinding parameters on tooth surface roughness. Therefore, we developed a prediction model for the worm tooth surface roughness under conjugate grinding and applied it to the Roller Enveloping Worm Reducer (REWR). The forming process of the theoretical worm tooth surface during the grinding process was modeled by using the conjugate meshing principle. Considering the plowing and cutting effects of grinding particles on the tooth surface at different design parameters, feed speeds, and rotational speeds of the grinding head, the roughness prediction equation was established based on the theory of the maximum depth of valley bottom. Through the coupling analysis of the theoretical tooth surface model and the roughness prediction model, the prediction of the worm tooth surface roughness is realized. Based on the validated model, the influences of grinding parameters on the worm tooth surface roughness of REWR were quantitatively discussed. This study is of great significance for optimizing process parameters in the grinding of complex spatial surface transmissions.

Multi-Step Two-Dimensional Ultrasonic-Assisted Grinding of Silicon Carbide: An Experimental Study on Surface Topography and Roughness.

Two-dimensional ultrasonic-assisted grinding (2D-UAG) has exhibited advantages in improving the machining quality of hard and brittle materials. However, the grinding mechanism in this process has not been thoroughly revealed due to the complicated material removal behaviors. In this study, multi-step 2D-UAG experiments of silicon carbide are conducted to investigate the effects of machining parameters on surface quality. The experimental results demonstrate that the tool amplitude and the workpiece amplitude have similar effects on surface roughness. In the rough grinding stage, the surface roughness decreases continuously with increasing ultrasonic amplitudes and the material is mainly removed by brittle fracture with different surface defects. Under semi-finishing and finishing grinding steps, the surface roughness first declines and then increases as the tool amplitude or workpiece amplitude grows from 0 μm to 8 μm and the inflection point appears around 4 μm. The surface damage contains small-sized pits with band-like distribution and localized grooves. Furthermore, the influences of cutting parameters on surface quality are similar to those in conventional grinding. Discussions of the underlying mechanisms for the experimental phenomena are also provided based on kinematic analysis. The conclusions gained in this study can provide references for the optimization of machining parameters in 2D-UAG of hard and brittle materials.

Effect of the Axial Profile of a Ceramic Grinding Wheel on Selected Roughness Parameters of Shaped Surfaces Obtained in the Grinding Process with a Dual-Tool Grinding Head.

The use of CNC equipment that integrates several machining operations eliminates downtime due to changes in setup and clamping of workpieces in more than one machining device. A review of CNC equipment and tools known from the literature and from manufacturers' offerings indicates that new technical solutions are being developed to integrate two or more technological operations. However, these examples have numerous limitations and are mostly not suitable for machining surfaces with complex shapes. An example of such solutions is the use of a dual-tool grinding head, which integrates the process of rough grinding with a ceramic grinding wheel and finish grinding with a flexible grinding wheel. Unfortunately, it has the disadvantage of being limited by the angular shape of the ceramic grinding wheel, making it unable to adapt to the complex geometries of the shaped surfaces being ground. The need to overcome this limitation became the motivation for the research work described in this article. By means of experimental research, it was verified what effect the radial outline on the periphery of a ceramic grinding wheel realized by rough grinding would have on the surface roughness parameters obtained in the process of grinding shaped surfaces. For this purpose, grinding processes using a ceramic wheel with a conical and radial outline were compared. The result of the study was a summary of the surface roughness parameters Sa, St, Sq, Spk, Str, and Sds obtained after two-stage machining (rough and finish grinding). The obtained analysis results showed that changing the axial outline of the ceramic grinding wheel makes it possible to significantly expand the range of applications of the dual-tool head without negatively affecting the quality of the machined surface. Thus, such an improvement will make it possible to increase the applicability of the head by grinding shaped surfaces with a radial profile of curvature.

Investigation on the Deformation and Surface Quality of a Bearing Outer Ring during Grinding Processing.

Thin-walled bearings are widely used owing to the advantages of their light structure, high hardness, and strong load-carrying capacity. However, thin-walled bearings are often prone to deformation during the machining process, which can seriously affect the performance of the bearings. In addition, the machining deformation and quality of bearings are difficult to balance. To address the above issues, this paper investigates the effects of the machining parameters on the machining deformation, surface quality, and machining efficiency of a thin-walled bearing during the roughing stage. The dynamic balance between deformation inhibition and high quality in rough grinding was studied, and the optimal parameters for thin-walled bearing outer ring grinding were obtained. The deformation mechanism of thin-walled bearings caused by grinding was revealed through simulation and experimental analysis. The results show that the machining deformation and quality reach a balance when the workpiece speed is 55 r/min, the grinding wheel rotational speed is 2000 r/min, and the feed rate is 0.1 mm/min. Deformation increases with the increase in workpiece speed and grinding wheel speed. At the same time, the surface roughness increases with the increase in the workpiece speed, but the increase in the wheel speed will improve the surface roughness. As the workpiece speed increases, the surface topography shows a more pronounced stockpile of material, which is ameliorated by an increase in grinding wheel speed. As the rotational speed of the workpiece increases, the number of abrasive grains involved in the process per unit of time decreases, and the surface removal of the workpiece is less effective, while the increase in the rotational speed of the grinding wheel has the opposite effect. The grinding deformation of thin-walled bearings is mainly induced by machining heat and stress. As the rotational speed increases, the heat flux in the grinding zone increases. More heat flux flows into the surface of the workpiece, causing an increase in thermal stresses on the inner surface of the bearing collar, leading to greater deformation. The temperature in the grinding area can be reduced during machining, realizing a reduction in deformation. The research content contributes to the balance between high quality and low distortion in machining processes.

Full-field measurement of residual stress in single-crystal diamond substrates based on Mueller matrix microscopy

In this work, a method has been proposed for fast-measuring full-field residual stress of diamond substrates based on Mueller Matrix (MM) microscopy. The measurement system features a polarization camera and a fixed compensator at 45° orientation, and real-time birefringence imaging can be performed. The magnitude and orientation of residual stress have been characterized by the stress-optical law. Optical-grade synthetic diamond substrates after laser-cutting and grinding have been measured. After laser-cutting samples exhibit a central region where stress orientation is shifted by −90° from the x-axis. After double-sided fine grinding, the average stress value is relatively low at 0.094 GPa, while single-sided fine grinding yields average stress of 0.142 Gpa, whereas double-sided rough grinding leads to 0.157 Gpa. Full-field stress distributions obtained from Raman images show consistent patterns. The research indicates that the MM-based method is a promising technique for detecting diamond substrate birefringence and characterizing its stress variation during fabrication.

Residual stress and subsurface damage in sapphire ultra-precision grinding

This study conducted experiments on ultra-precision grinding of sapphire using various strategies. It evaluated surface and subsurface characteristics across multiple dimensions, including morphology, scale, mechanical properties, residual stresses, lattice distortions, in-service properties, and chemical components. The research aimed to explore the intrinsic relationship between these behaviours. The findings revealed that both semi-finish grinding and ultra-precision grinding achieved ductile and low-roughness surfaces, with surface hardness enhancement near the grinding surface. Additionally, Raman spectra wave shifts were able to distinguish residual stresses at different grinding strategies, with larger stresses observed in ultra-precision grinding compared to semi-finish grinding and rough grinding. Furthermore, dense etching dislocation pits were observed on the ultra-precision grinding surface, responding to the scale of residual stress. The presence of larger subsurface cracks in semi-finish grinding and rough grinding was found to contribute to the release of residual stress. Moreover, ultra-precision grinding significantly reduced subsurface damage compared to rough grinding, with a reduction from 23.8 μm to 4.3 μm. Photothermal absorption during rough grinding was noted to be over 10 times higher than in ultra-precision grinding. Transmission electron microscopy (TEM) analysis revealed that subsurface damage included microcrack-induced line defects and uniform plastic deformation areas. This damage involved lattice aberrations, dislocations, stacking faults, and thin amorphous layers. The hardness and modulus of the subsurface damage layer were observed to decrease. Additionally, Raman spectra wave shifts were able to distinguish the subsurface damage layer in ultra-precision grinding. Energy-dispersive X-ray spectroscopy (EDS) analysis showed no change in the chemical components of the subsurface damage layer. Furthermore, a model was proposed to evaluate subsurface damage based on residual stress, and the mechanism of residual stress inducing damage in ultra-precision grinding was further analysed.

Study on Plastic Deformation Removal Mechanism and Dislocation Change in Nanogrinding of Single Crystal Silicon Carbide with Random Rough Surface

This investigation centers on exploring the plastic deformation removal mechanism and dislocation dynamics in the nanogrinding of single‐crystal silicon carbide featuring a randomly rough surface. To simulate this, an approach combining the Weierstrass–Mandelbrot fractal surface function with molecular dynamics is employed. Randomly rough surface contours are generated using the Weierstrass–Mandelbrot fractal surface function. By adjusting the fractal dimension, an ideal representation of single‐crystal silicon carbide with randomly rough surfaces is obtained. By combining plastic deformation detection methods, the process of workpiece sliding, plowing, and chip removal is studied, and the plastic deformation removal mechanism of random rough surface grinding is explored. Combining postprocessing methods such as sheer strain and dislocation trajectory, the morphological changes and transformation mechanisms of dislocations are analyzed. Notably, at grinding depth of 33.18 nm, the activation of slip systems induces dislocation formation, enabling plastic deformation. Furthermore, at depths exceeding 144.00‐nm, the emergence of stacking faults on the random rough surface is observed. Throughout the grinding procedure, plastic deformation of debris occurs, leading to the formation of plastic bulges on both sides of the tool, and the debris generated during processing does not impact the defects encountered during secondary grinding of the rough surface.

Влияние микрогеометрических параметров сферической поверхности ролика на звуковое давление и вибрацию подшипника

In a production environment of JSC UPC Volzhsky it is shown how to increase the vibration discharge of bearings with conical rollers due to the use of rollers with the specified microgeometric parameters of the spherical surface made in the general production flow. The sphere is formed under the combination of rough grinding, finish grinding and final grinding using an assembled abrasive tool consisting of three rolls of various characteristics. It was found that in a bearing, with sequential replacement of rollers, where sphere roughness varies in the range of 0.10 Ra ≤ 0,.20 microns for rollers with roughness Ra ≤ 0,10 microns, the average value of the microgeometric parameters of the roller sphere in bearings (Ra, undulation W, deviation of circularity Δ) decreases by 2,4 – 4,3 times. The impact assessment of bearing rollers set having different parameters of the microgeometry of the spherical roller end on the sound pressure and vibration of the bearing was carried out. It was found that with an increase in the number of rollers with microgeometric parameters of the sphere closer to the lower edge of the tolerance field, the values of the overall vibration level, the vibration level in the third frequency band and the sound pressure level of the bearing improved. A statistical analysis of these parameters was carried out. The significance of the analyzed factors and conditions for increasing the vibration discharge of the bearing while ensuring processing modes within the framework of the current technological process are determined. Correlation and functional relationships between the average values of the microgeometric parameters of rollers spheres in bearings and the parameters of sound pressure and vibration were found.

The Grinding and Polishing Technology for Various Materials

We (Okamoto Machine Tool Works, Ltd.) present our grinding and polishing technology for various materials such as resin, Cu, BG tape, SiC, GaN. Our technology is able to grind and polish various types of materials from soft materials to hard materials. We have been developing a special grinding technology for soft materials. The technology is called HPD and enables to grind the soft materials which were not able to be ground with a standard grinding process or needed to be ground by rough grid size grinding wheels. You also had to make the grinding wheel wears a lot even the rough grid size grinding wheels are used in order to grind those soft materials due to the clogging. The HPD technology prevents this issue. Moreover, thanks to this technology, you can use high mesh wheels such as #4000 - #30,000. We believe that the HPD technology can be an effective technology for FOWLP, PLP, TSV grinding and BG tape grinding of flip-chip/high bumped wafers for flatness improvement. Our technology is not only for soft materials but also for difficult cut materials such as SiC and GaN. We developed high power and high-rigidity grinder for these materials. We are going to look through the SiC grinding result with our technology. Moreover, we have developed polishing technology for various types of materials including Si, SiC, GaN, InP, GaAs, and more. Our grinding and polishing technology can cover various types of materials. It is hoped that our technology helps your current process issues.

Experimental Study on ELID Grinding of Silicon Nitride Ceramics for G5 Class Bearing Balls

This study has focused on analyzing the impact of material characteristics and grinding conditions on the surface roughness in ELID grinding of ceramic materials intended for bearing balls. The main research objective was to examine the feasibility of achieving the required surface roughness for G5 class bearing balls through a high-efficiency and high-precision ELID grinding process. Three types of silicon nitride specimens and two types of grinding wheels with cBN and diamond abrasives were prepared for the experiments. An HP (high-pressure) specimen was fabricated through high-temperature and high-pressure sintering at 1700 °C for 2 h, containing a composition of Y2O3 and MgO in Si3N4, while GPS 1hr and GPS 6hr specimens were prepared using gas-pressure sintering for 1 h and 6 h, respectively. From the experimental results, it has been confirmed through surface morphology and surface roughness analysis that material characteristics and grinding parameters affect the surface roughness of silicon nitride ceramics during the grinding process. The surface ground with a #2000 diamond wheel is at a level that can satisfy the required surface roughness, 0.014 um or less in G5 class bearing balls. Based on the analysis of surface morphology and roughness in grinding processes, the #325 cBN wheel exhibited excellent performance in rough grinding, while the #2000 diamond wheel demonstrated highly effective surface finishing performance, indicating that the combination of these two abrasives can be effectively utilized for high-efficiency and high-precision nanosurface machining of silicon nitride ceramics.

Experimental Investigation on Microstructure Alteration and Surface Morphology While Grinding 20Cr2Ni4A Gears with Different Grinding Allowance Allocation.

Transmission gear is a key component of vehicles and its surface integrity affects the safety of the transmission system as well as the entire mechanical system. The design and optimization of allowances in form grinding are important for improving dimensional accuracy and machining efficiency during the manufacturing of heavy-duty gears. This work aims to investigate the effects of grinding allowance allocation on surface morphology, grinding temperature, microstructure, surface roughness, and microhardness fluctuation during the form grinding of 20Cr2Ni4A gears. Results indicated that grinding temperature was primarily influenced by rough grinding involving significant grinding depths exceeding 0.02 mm. The ground surface exhibited slight work hardening, while thermal softening led to a reduction in microhardness of around 40 HV. Ground surface roughness Ra varied from 0.930 μm to 1.636 μm, with an allowance allocation of the last two passes exerting the most significant influence. Analysis of surface and subsurface microstructures indicated that a removal thickness of 0.02 mm during fine grinding was insufficient to eliminate the roughness obtained from rough grinding. Evident ridges, gullies, and surface defects such as material extraction, adhesion, and plastic deformation were also observed. The proposed grinding strategy was validated in practical manufacturing with good surface quality and geometrical accuracy.

ВЛИЯНИЕ СТРУКТУРЫ И ТВЕРДОСТИ АБРАЗИВНОГО ИНСТРУМЕНТА НА ПОКАЗАТЕЛИ ШЛИФОВАНИЯ БЫСТРОРЕЖУЩЕЙ СТАЛИ

The operation of flat mortise grinding of high-speed steel blanks are presented. The regularities of changes in the components of the cutting force, the grinding coefficient and the arithmetic mean deviation of the profile of the treated surface during grinding with circles of different hardness and structure are determined. Recommendations on the choice of characteristics of the abrasive tool, modes of finishing and rough grinding of high-speed steel are given.

Feasibility Study of Integrated Precision Abrasive Machining of Shaped Surfaces

The use of CNC equipment that integrates several machining operations allows the elimination of downtime resulting from setup changeovers and the clamping of workpieces in several different machine tools. More and more CNC machines and tools that allow the integration of several machining operations are appearing on the market, but there are only a few examples of these and many solutions that allow such integration for more complex operations are still missing. The aforementioned factors motivated the research work described in this paper. The purpose of the present study was to develop an innovative grinding head with different functional features for use in the process of shaped surfaces face grinding, the use of which will enable complete abrasive machining in a single mounting. The conducted tests of the grinding process showed a reduction in the values of the roughness parameters Sa (5.30, 1.12, 0.63 μm), St (31.8, 14.4, 6.72 μm), Sq (6.39, 1.46, 0.81 μm) and Spk (6.16, 0.77, 0.33 μm) and an increase in the value of the parameter Sds (393, 563, 1203 pks/mm2) on the surface after machining in two stages, first for rough grinding and then for finishing relative to the surface after the shaped milling process.

Review on Research and Development of Abrasive Scratching of Hard Brittle Materials and Its Underlying Mechanisms

Hard brittle materials such as ceramics and crystals are commonly utilized in various industries, including information technology, mechanical engineering, and semiconductors. These materials, known for their high brittleness and hardness but low fracture toughness, pose challenges in efficient and high-quality machining. Current abrasive machining techniques involve rough grinding, fine grinding, and polishing processes, with the latter being the most time-consuming and accounting for over half of the total machining time. Improving processing parameters in rough and fine grinding can increase machining efficiency, reduce surface and subsurface damage, and improve workpiece quality, ultimately reducing the polishing time. This paper explores the abrasive scratching of hard brittle materials, examining the nucleation and propagation of cracks causing surface and subsurface damage, and the underlying mechanisms. The research provides suggestions for enhancing abrasive machining efficiency and ensuring the surface quality of hard brittle materials.

Surface Quality Evolution Model and Consistency Control Method of Large Shaft Multi-Pass Grinding

Large shaft usually achieves high surface quality through multi-pass grinding in practice. Common surface quality indexes include surface roughness and glossiness, which are not only required numerically, but also require high consistency of distribution along the whole shaft. In multi-pass grinding, these two indexes are affected by the process parameters and the surface quality of the previous grinding pass, which leads to the difficulty of modeling. In addition, due to the uneven distribution of actual grinding depth, the surface quality along the whole shaft is usually inconsistent, resulting in the need for multiple spark-out grinding passes to ensure consistency. In this study, the surface quality evolution models for surface roughness and glossiness based on Elman neural network are developed, which build regressions between process parameters, surface quality indexes of the previous grinding pass, and surface quality indexes of the current grinding pass. Moreover, a consistency control method of surface quality is proposed by adjusting the actual grinding depth within the dimensional accuracy tolerance range at the rough grinding stage. Experimental results show that the surface roughness and glossiness prediction errors of the surface quality evolution models are only 5.5% and 5.1%. The consistency control method guarantees the consistency of surface quality, reduces the grinding passes, and increases the grinding efficiency.

Optimization of Grinding Parameters of Tool Steel by the Soft Computing Technique.

Grinding is one of the most complex and accurate machining processes, and the efficiency of the grinding wheel depends significantly on its surface properties. This work aims to propose an algorithmic manner that reduces the cost and time to conduct grinding of an optimized DIN 1.2080 tool steel (SPK) using a soft computing technique to obtain the best combination of input parameters including depth of cut (20, 40, 60 μm), wheel speed (15, 20, 25 m/s), feed rate (100, 300, 500 mm/s), and incidence angle (0, 30, 45 de grees) with respect to output parameters consisting of average surface roughness and specific grinding energy. According to the input parameters and their levels, an experiment using fractional factorial design of experiment (RFDOE) was designed. Later on, two parallel feed-forward backpropagation (FFBPNN) networks with similar topology made up of 4, 11, and 1 units in their input, hidden, and output layers are trained, respectively. After sensitivity analyses of networks for determination of the relative importance of input variables, a genetic algorithm (GA) adopting linear programming (LP) based on Euclidean distance is coupled to networks to seek out the best combinations of input parameters that result in minimum average surface roughness and minimum specific grinding energy. The findings revealed that RFDOE provides valid data for training FFBP networks with a total goodness value of more than 1.99 in both cases. The sensitivity analyses showed that feed rate (38.97%) and incidence angle (33.94%) contribute the most in the case of average surface roughness and specific grinding energy networks, respectively. Despite the similar surface quality based on scanning electron microscopy (SEM), the optimization resulted in an optimized condition of the depth of cut of 25.23 μm, wheel speed of 15.02 mm/s, feed rate of 369.45 mm/s, and incidence angle of 44.98 de grees, which had a lower cost value (0.0146) than the optimum one (0.0953). Thus, this study highlights that RFDOE with a hybrid optimization using FFBP networks-GA/LP can effectively minimize both average surface roughness and specific grinding energy of SPK.

RESEARCH OF THE DEPTH OF GRINDING

The article presents a model of a dynamic rough grinding system (DSOS) with the impact on it ofthe curvature of the rolled product and the discontinuous surface of the grinding wheel. The analysis ofthe model of a dynamic system for rough grinding is carried out by direct simulation on a computer andby means of the amplitude-frequency characteristic of the system. This analysis allows you to assignrough grinding conditions to achieve the quality requirements for rolled products after rough grinding.