Traditional Grinding Research Articles

Review of advanced sensor system applications in grinding operations.

Today, in a wide variety of industries, grinding operations are an extremely important finishing process for obtaining precise dimensions and meeting strict requirements for roughness and shape accuracy. However, the constant wear of abrasive tools during grinding negatively affects the dimensional and surface conditions of the workpiece. Therefore, effective monitoring of the wear process during grinding operations helps to predict tool life, plan maintenance and ensure consistent product quality. The objective of this review is to examine current tool condition monitoring techniques, both direct and indirect, in various sensor systems and their application in both traditional and AI-driven grinding processes. By examining these techniques, the review provides insight into how different monitoring techniques can improve process efficiency, reduce downtime, and improve finished product quality, as well as the application of intelligent and adaptive processes to traditional grinding operations. Key Scientific Concepts of Review: The review discusses the critical role of sensor systems in monitoring tool condition, including technologies such as imaging, vibration analysis, acoustic emission, and force measurement. These systems are vital for detecting wear and predicting failures, allowing for timely interventions and preventing unplanned downtimes. The integration of artificial intelligence into these monitoring systems greatly enhances their capabilities, as they enable more proactive strategies and adapt to changing conditions during the grinding process.

Design and Preparation of a Self-Inhaling Internal Cooling Grinding Wheel with a Leaf Order Arrangement Structure

Grinding wheels are important tools for precision machining. Traditional grinding wheels have issues such as high grinding forces and temperatures on the machined surface, and excessive use of grinding fluids often leads to significant waste. To solve such problems, this paper proposes a self-inhaling internal cooling structured grinding wheel with a leaf order arrangement based on laser cladding technology, by which the “air barrier effect” in grinding is avoided. In this study, the structure of the grinding wheel substrate, as well as the arrangement of abrasive grain clusters, were optimized. The internal flow field and grinding zone flow field of the grinding wheel were simulated using the computational fluid dynamics method. To ensure stable grinding performance, the effects of different cooling hole positions and sizes on fluid motion were revealed, and the influence of grinding wheel rotational speed and coolant pressure on outlet velocity were analyzed. The results show that uniform coolant outlet velocity distribution can be achieved via matching the grinding wheel’s rotational speed with the initial pressure of the cooling fluid inside the grinding wheel. This study further explored the fluid motion patterns in the grinding zone for four differently structured surfaces. The advantages of using leaf order theory to arrange abrasive clusters were verified. Additionally, orthogonal experiments and range analysis were conducted to study the laser cladding preparation process of grinding wheels. With the optimal process parameters, a self-inhaling internal cooling grinding wheel with a leaf order arrangement structure was fabricated.

FEATURES OF THE DESIGN OF VERTICAL ROLL MILLS FOR EFFICIENT GRINDING OF CEMENT AND GRANULAR SLAG

The article discusses the design features of vertical roller mills used for grinding cement and granular slag. An analysis of the main design elements, such as rolls, grinding tables and drive systems, is made, with an emphasis on their influence on productivity and grinding quality. Both the history of changes in the designs of roll mills and the introduction of the latest engineering solutions aimed at increasing the efficiency of the grinding process, reducing energy consumption and improving the operational characteristics of the equipment were studied. The advantages of using vertical roller mills in comparison with traditional grinding technologies in the production of cement and slag-alkaline materials have been determined.

A Review of Insights and Research Progress on Hard Turning

Of late, due to the launch of improved machine tool designs and extremely hard cutting tools, “Hard Turning” (HT) or “Hard Finish Turning” (HFT) has turned out to be an innovative, cost-effective, and smart alternative to the traditional grinding and subsequent superfinishing processes. As a result, HT clenches the potential to produce excellent part quality in very little time along with negligible additional costs, which is considered to be a boon for the manufacturing industries. Hence, an attempt was made to review the development, key insights, and research progress in the HT process. So, a huge pool of HT studies has been reviewed to achieve a better understanding of the evolution and key insights namely process, workpiece materials, cutting inserts, machine tools, and machining parameters. Additionally, the effectiveness of HT using CBN (Cubic Boron Nitride) insert under different machining conditions is briefed. The review highlights the growing potential of HT in modern manufacturing and outlines the challenges and future research direction.

The Effect of Ultrasonic Vibration on the 3D Printing Fabrication and Grinding Performance of Structured CBN Grinding Wheel.

The abrasives of traditional grinding wheels are usually randomly arranged on the substrate, reducing the number of effective abrasive grains involved in the machining during the grinding process. However, there are some problems such as uneven distribution of chip storage space, high grinding temperature, and easy surface burn. In trying to address this issue, an ultrasonic vibration 3D printing method is introduced to fabricate the structured CBN (Cubic Boron Nitride) grinding wheel. The effects of the fabricated process parameters, overlap rate, scanning path, and ultrasonic amplitude were analyzed. The effects of laser power, scanning speed, and powder disk rotation speed on the topography of the printing layer were analyzed by orthogonal tests. The obtained data were input into the GA-BP (Genetic Algorithm-Back Propagation) neural network for training, and the trained model was utilized to derive the optimal process parameters. Then, the experiments were carried out to optimize the overlap rate and the scanning path. The effect of ultrasonic vibration amplitude on the surface topography and the microhardness of the printing layer was observed and investigated. The structured CBN grinding wheels were fabricated using the optimal parameters, and the performance of the grinding wheels was evaluated. The workpiece surface roughness ground by the grinding wheel fabricated with ultrasonic vibration was smaller than that without ultrasonic vibration, and a better workpiece surface quality was obtained.

Research on the material removal mechanism of vibration-assisted nano-scratch on single-crystal GaN by molecular dynamics.

Single-crystal gallium nitride (GaN) is a semiconductor material known for its hardness and brittleness. This research aims to reveal the differences in the micro-mechanisms of material removal during traditional grinding and ultrasonic vibration-assisted grinding and to provide guidance for the high-efficiency, high-quality planarization processing of single-crystal GaN. To achieve this purpose, molecular dynamics (MD) simulation methods were used to establish a model (30nm × 40nm × 15nm) of single-crystal GaN being scratched by a single abrasive grain with and without ultrasonic vibration assistance. The differences in the surface morphology and subsurface damage formation mechanisms of single-crystal GaN under conditions with and without ultrasonic assistance were compared. The results indicate that, compared to traditional grinding, the periodic ultrasonic vibrations reduce the normal force and result in a more uniform distribution of stress and temperature, thereby mitigating local stress concentration and thermal accumulation effects. Ultrasonic vibration alters the motion of the abrasive grain, expanding the material removal range from 7.384 to 10.315nm, decreasing the number of residual atoms in the machining area, and lowering the chip pileup height at the leading edge of the abrasive grain from 2.063 to 1.528nm. Additionally, the micro-shear deformation induced by ultrasonic vibrations helps to suppress brittle fracturing caused by excessive local stress, thus reducing the thickness of the damaged subsurface. At a scratch depth of 2nm, the total length of dislocation lines in the ultrasonic-assisted scratch is reduced from 185.256 to 33.315 nm compared to traditional scratching. These findings offer new insights into the microscopic mechanisms of material removal in high-efficiency, high-quality grinding processes of single-crystal GaN. This study adopts LAMMPS software for MD simulations to investigate the physical behavior of GaN during the grinding process. The simulation results are then visualized and analyzed using OVITO software to elucidate microstructural changes in the material. During the simulation, the temperature of the Newtonian layer is calculated based on the statistical analysis of atomic velocities under the NVE ensemble. The grinding force applied to the GaN workpiece is determined by differentiating the atomic potential energy. Von Mises stress analysis is adopted to ascertain the stress distribution during the scratching process. Finally, the changes in the crystal structure during scratching are identified and classified using analysis of identified defect structures.

No-impact trajectory design and fabrication of surface structured CBN grinding wheel by laser cladding remelting method

The structured grinding wheels have a specially designed macro or microstructure on the surface, with a relatively low average grinding force and temperature in the cutting zone and more space for chips and coolant. Most traditional grinding wheel fabrication methods, such as electroplating, sintering, and brazing, have the problems of poor abrasive grain holding strength, random abrasive distribution, or thermal deformation of the substrate. To address this, laser cladding remelting technology is introduced to fabricate the structured CBN grinding wheel. A no-impact trajectory was designed on the substrate of the grinding wheel, which can reduce the fluid friction in the channel and increase the fluid pressure at the outlet. The temperature and velocity fields of the grinding process were simulated to verify the feasibility of the designed structure theoretically. The optimal process parameters for the bonding among the metal bond, the abrasive grains, and the substrate were determined by orthogonal and full-scale factorial experiments. The chemical metallurgical reactions between CBN grain and metal bond, as well as between the metal bond and substrate, were formed, increasing the holding force of CBN grains. The method can realize the fabrication of high-strength and long-life structured grinding wheels with an orderly arrangement of abrasive grains. The micro-mechanism of fabrication was analyzed using element distribution measurement and XRD analysis.

Effects of ultrafine grinding on nutritional, physicochemical and protein composition of Acheta domesticus powder

Acheta domesticus is a new source of high-quality protein, but the accessibility and acceptability of protein is notably limited by the particle size of the house cricket powder, and little information about the effect of particle size on the house cricket powder had been reported. In this study, four kinds of ultrafine cricket powder were obtained by two industrial methods, and compared with the traditional grinding powder. The results illustrated that ultrafine grinding technology could increase the powder properties, such as the thermal stability, crystallinity, color brightness, protein extraction rate and amino acid content, especially the essential amino acid (EAA) content were significantly improved. And the properties and nutrient release of the powder are mainly related to the particle size rather than the method. The results have a certain guiding effect on the development and application of ultrafine house cricket powder as a multifunctional nutrient.

The Process Optimization Analysis of CBN Abrasive Cu-Sn-Ti Coating Fabrication via the Ultrasonic-Vibration-Assisted Laser Cladding Method

Ultra-precision machining has higher requirements for the performance of abrasive tools, but the traditional grinding wheel has some problems such as irregular grain arrangement, limited chip space, and high grinding temperature. Therefore, a structured grinding wheel suitable for ultra-precision machining is proposed. In this study, the laser cladding method and ultrasonic vibration technology were combined to study the preparation process of a structured grinding wheel. Firstly, the quality evaluation system of the printing layer was established, and the shape coefficient and dilution rate were used to evaluate the laser cladding quality. The effects of laser power, sweep speed, powder feeding speed, and ultrasonic power on the shape coefficient and dilution rate of the printing layer were analyzed by single-factor experiments. The level range of each factor in the orthogonal experiment was established to optimize the process parameters. The surface morphology was observed, and the influence of ultrasonic vibration on the morphology was analyzed. The structured grinding wheel was prepared according to the optimized parameters.

A Review of High-Speed Turning of AISI 4340 Steel with Minimum Quantity Lubrication (MQL)

AISI 4340 is a medium-carbon low-alloy steel that has gained distinctive attention due to its advanced properties including high strength, high toughness, and heat resistance. This has led to its commercial usage in a wide variety of industries such as construction, automotive, and aerospace. AISI 4340 is usually machined in a hardened state through a hard-turning process, which results in high heat generation, accelerated tool wear, low productivity, and poor surface quality. The application of high-speed machining helps improve the material removal rate and surface finish quality, yet the elevated temperature at the cutting zone still poses problems to the tool’s lifespan. Apart from using advanced cutting tool materials, which is costly, researchers have also explored various cooling methods to tackle the heat problem. This paper presents a review of a sustainable cooling method known as minimum quantity lubrication (MQL) for its application in the high-speed turning of AISI 4340 steel. This study is centered on high-speed turning and the application of MQL systems in machining AISI 4340 steel. It has been observed that the hard part turning of materials with a hardness exceeding 45 HRC offers advantages such as improved accuracy and tighter tolerances compared to traditional grinding methods. However, this process leads to increased temperatures, and MQL proves to be a viable alternative to dry conditions. Challenges in optimizing MQL performance include fluid penetration and lubrication effectiveness.

Modeling and simulation of temperature field in high-shear and low-pressure grinding with liquid-body-armor-like grinding wheel

High-shear and low-pressure grinding using liquid-body-armor-like grinding wheel is a new grinding process. It has a great potential in the field of precision and ultra-precision machining. To clarify the unclear grinding heat characteristics, heat generation mechanism, and heat source distribution of the liquid-body-armor-like grinding wheel, a temperature field model was developed for high-shear and low-pressure grinding with ABAQUS. The thermal characteristics of the new grinding wheel were investigated by studying the heat flux and convective loads under different grinding parameters. The effectiveness of the heat model was validated through high-shear and low-pressure grinding experiments. The simulation results closely matched with the experimental results, with an average error of 5.84 % and a minimum error of 0.94 %. The grinding temperature decreased gradually from the centre of the heat source towards the edge of the workpiece in both horizontal and vertical directions. The temperature raised with the increase of the grinding velocity, ranging from 39.66 °C at 4 m/s to 77.82 °C at 14 m/s. It decreased with the workpiece feed rate, dropping from 39.66 °C at 500 mm/min to 32.00 °C at 3000 mm/min. As the normal grinding force increased, it gradually increases from 30.80 °C to 39.66 °C. The grinding temperature of the liquid-body-armor-like grinding wheel was lower than that of the traditional grinding wheel.

Investigation of Single Grain Grinding of Titanium Alloy Using Diamond Abrasive Grain with Positive Rake Angle

Traditional grinding, which is predominantly performed with a negative rake angle (NRA), can be transformed into grinding with a positive rake angle (PRA) by employing femtosecond pulsed laser technology to modify the apex angle of the grains to be less than 90°. This innovative approach aims to reduce grinding forces and grinding temperatures while improving the surface quality of typical hard-to-machine materials. To assess the performance of PRA single grain grinding and to investigate the underlying mechanisms, the finite element simulation software ABAQUS 6.14 was employed to model the grinding of Ti6Al4V titanium alloy with a single diamond abrasive grain. The dependence of grinding force and temperature in single grain grinding with a PRA or an NRA under different grinding parameters was studied and compared. PRA and NRA single diamond grain grinding experiments on Ti6Al4V alloy were carried out, with grinding forces measured using a dynamometer and compared with the simulation results. The grinding surface morphology and surface roughness were observed and measured, and a comparison was made between PRA and NRA grinding. The results indicated that in single diamond grain grinding, transforming to a PRA significantly enhances grinding performance, as evidenced by reduced grinding forces, lower temperatures, improved surface morphology, and decreased surface roughness. These findings suggest that PRA single diamond grain grinding offers substantial benefits for the precision machining of hard-to-machine materials, marking a step forward in optimizing surface finishes.

Grinding performance of MgF2 ceramics using biomimetic shark fin grinding wheels with different structure parameters

In the field of precision machining, with the popularity of brittle and hard materials such as infrared windows, it has become difficult for conventional diamond grinding wheels to effectively perform high-quality machining. The structuring of traditional diamond grinding wheels using a pulsed laser is a key technology to effectively improve the grinding quality of grinding wheels. In this paper, three new shark fin diamond grinding wheels (SFSGW) with different slot widths are designed based on the excellent drag-reducing and channelizing properties of shark dorsal fins. The grinding performance of traditional grinding wheels (USGW) and SFSGW on magnesium fluoride ceramics was compared. The effects of SFSGW on the surface quality, surface roughness and wheel damage of the workpiece were investigated. The results showed that the surface roughness of ceramics after grinding by SFSGW was reduced by 22.15 % compared with USGW, and the surface quality was better. Proper construction increases the material removal rate of the wheel and improves the wear resistance and service life of the wheel.

Surface Quality of High-Concentration SiC/Al Grinding with Electroassisted Biolubricant MQL

SiC/Al composites are widely used in aerospace and other fields due to their excellent mechanical properties. For large-concentration composites, due to the extremely high proportion of SiC and the unstable interface between the two phases, the SiC particles are broken and detached during the processing, which makes the surface quality of the workpiece insufficient to meet the service requirements. Electrically assisted cutting technology is expected to break through this technical bottleneck. This paper investigates the surface quality of high-concentration SiC/Al grinding with electroassisted biolubricant MQL. The surface morphology after processing is observed. Firstly, by comparing the traditional grinding and electrically assisted grinding conditions, it is found that the fundamental reason for the improvement in the grinding surface quality using a pulse current is the improvement in the Al plasticity. Secondly, based on the thermal effect and non-thermal effect of the pulse current, the influence of the electrical parameters (current, duty cycle and frequency) on the machining indication quality is discussed. It is found that when the current and duty cycle increase, the machining surface quality will also increase, while the frequency change has little effect on the surface quality. Finally, friction and wear experiments are carried out on the grinding surface under different working conditions to explore the friction and wear characteristics of the surface of the workpiece. The results show that the pulse current can significantly improve the wear resistance of the grinding surface.

Research on Ultrasonic Vibration Assisted Grinding Technology of Quartz Fiber Reinforced Ceramic Matrix Composites

Ceramic matrix composites have good mechanical properties and high temperature resistance, but it is difficult to process. In order to solve the problems of fast tool wear and low machining efficiency in the dry grinding process, ultrasonic vibration assisted grinding technology of quartz fiber reinforced ceramic matrix composites is adopted in this paper. Grinding force, machining efficiency, tool wear and surface roughness are analyzed through the comparison experiment between the conventional grinding and the ultrasonic vibration assisted grinding. The influence of the ultrasonic vibration assistance and process parameters on machining quality and tool life is further obtained. According to the findings, when compared to traditional grinding, ultrasonic vibration grinding can lower the grinding force by 25% to 58% and the surface roughness by up to 16%. The tool life and machining efficiency can be significantly increased with the help of ultrasonic vibration.

Fabrication of polycrystalline diamond micro-milling cutter with different grain sizes by picosecond laser

Polycrystalline diamond (PCD) is an excellent material for machining micro-tools due to its high hardness and wear resistance. However, the diameter of micro-milling tools is generally required to be less than 500 μm. When preparing micro-milling tools with a large aspect ratio, the processing load introduced by traditional grinding methods is easy to cause tool fracture. Therefore, a composite structure of carbide tool holder and diamond tool head is proposed in this paper. A technique of picosecond laser machining PCD micro-milling tool was studied, and the overall manufacturing process of tool blank preparation, nanosecond laser roughing and picosecond laser finishing was formed. A two-dimensional ablation mathematical model for tangential machining of PCD with a multi-pulse picosecond laser was established, and experiments verified the reliability of the mathematical model. In addition, the effects of picosecond laser pulse pitch, pulse energy, and track spacing on the surface quality of PCD materials with different particle sizes and cutting edge radius were studied by orthogonal experiments. The results showed that after picosecond laser processing, the surface roughness (Sa) of PCD with a particle size of 2 μm was the best, which can reach 0.33 μm, and the cutting edge radius of PCD micro-milling tool with a particle size of 25 μm was the smallest, which can get 1.67 μm. Using the optimized picosecond laser parameters, the high-sharpness single-edge micro-milling cutters with different particle sizes PCD with a diameter of 100 μm, aspect ratio greater than 3, and a cutting edge radius less than 3 μm were successfully fabricated.

Freeform surfaces manufacturing of optical glass by ultrasonic vibration-assisted slow tool servo turning

The optical glass is a typical difficult-to-cut material for single-point diamond turning because of its high hardness and low fracture toughness. The application of high-frequency vibration-assisted technology can make it a machining method for processing optical glass materials. However, due to the lack of understanding of intermittent cutting characteristics, it is still a challenge to achieve a high-precision and crack-free freeform surface on hard-brittle glasses. Therefore, the freeform surfaces of optical glasses are processed by ultrasonic vibration-assisted slow tool servo turning (UVSTS). The crack evaluating model of UVSTS turning is established based on the theory of specific cutting energy to predict fracture formation at all cutting position points of the freeform surface. Furthermore, the mechanisms of fracture initiation are analyzed and discussed deeply according to different factors. Finally, the bidirectional sinusoidal surface as a representative freeform surface is successfully fabricated on N-BK7 glass materials. The surface roughness can reach 1 nm Sa only by UVSTS turning without requiring any subsequent processing (including grinding or polishing). The research findings show the UVSTS turning technology can be used as a new machining method with high precision and high efficiency to replace traditional grinding and polishing technology for processing the optical elements of the freeform surface of glass materials.

Surface crack analysis of 8Cr4Mo4V steel based on Crystal/Phase microstructure model by grinding

Metal polycrystalline materials tend to be homogeneous and isotropic at the macroscopic level, which leads it difficult to visually characterize the sprouting and expansion of cracks by traditional grinding simulation. In this study, the Johnson–Cook constitutive model was used for the finite element method (FEM) based on grinding characteristics with a high strain rate and large plastic deformation. The models are focused on the actual microstructure distribution, one of them contains grains and grain boundaries, and another contains phase organization (martensite and acicular martensite) and carbides. The study pinpoints the changes in microstructure under different grinding parameters during the grinding process and the influences on the formation of microscopic cracks. Ultimately, it was found that the shedding of large primary carbide is a critical factor for inducing surface cracks. The uncoordinated deformation between brittle carbides with the other phases is the main cause of carbide shedding. Therefore, this article visualized shows the influence of grinding parameters on surface cracks from the perspective of microstructure modeling, which is of great significance in guiding practical processing.

Effect on Fine Particles Output Characteristics of Ceramic Ball Grinding

Steel balls as traditional grinding media are prone to excessive fines generation and high energy consumption. Therefore, in light of this problem, the authors investigated another media—ceramic balls based on the output characteristics of fine particles. This study discusses the effect of ceramic balls on the change of the particle size distribution, zero-order output characteristics, micro-strain, and collision energy in ground products. The results showed that for −10 μm particle size, ceramic balls have a smaller production rate than steel balls. In addition, when the filling rate of ceramic balls is 40%, the yield of −10 μm is reduced compared to steel balls. Therefore, ceramic balls greatly reduced the overgeneration of fines. Additionally, the micro-strain rate of ceramic ball grinding with time is 67% lower than that of steel ball grinding. Furthermore, ceramic balls cannot only mitigate excessive fines generation but also effectively reduce energy consumption.

New insights into the off-flavor improvement of soymilk by three grinding processing: Dry-blanching grinding, wet-blanching grinding, and wet-anaerobic grinding

Advances in grinding strategies have been beneficial to eliminating the off-flavor of soymilk and improving the quality soy products. Herein, four grinding processing, dry-blanching grinding (D-BG), wet-blanching grinding (W-BG), wet-anaerobic grinding (W-AG) and traditional grinding (TG) were employed and found to impose a significant impact on off-flavor components, accompanied by changes of hydroperoxides and free radicals. The results showed that all three methods could significantly hinder the formation of C6 aldehydes. C8 Alcohols and (E)-2-heptenal could be removed by D-BG, but lipids in dehulled soybean were prefer to be oxidized during storage, resulting in the accumulation of hydroperoxides and radicals. W-BG and W-AG have higher levels of 1-octen-3-ol, and soaking at an alkaline pH and increasing the number of rinses is beneficial for its removal. Gas chromatography-olfaction-mass spectrometry (GC-O-MS) combined with sensory evaluation showed that off-flavor profile of d-BGS, W-BGS and W-AGS was different. D-BG and W-AG possessed better flavor quality.