Metal Bonded Diamond Grinding Wheels Research Articles

Laser dressing of fine-grained metal-bonded diamond grinding wheels with concave surface

Electrical Discharge Dressing (EDD) of fine-grained metal-bonded diamond grinding wheel is the most recognized processing method in the industry at present. In this paper, the processing method of nanosecond pulse laser dressing of fine-grained metal-bonded diamond wheel with concave surface was proposed. The main components of the heat affected zone on the sub-surface of the wheel after laser dressing were proposed. The influence of the laser circumferential overlap ratio (OC) on the size of the heat affected zone of the metal-bonded material was systematically studied, and the formation mechanism of the angle error of the wheel with different influence degree of two kinds of effects was explained as the result of the change of laser energy density. The results demonstrated that with the increase of OC, the burn degree and sub-surface quality of the wheel surface became worse. The optimal laser circumferential overlap ratio OC was 30 %. It was found that the laser energy was continuously lost with the decrease of the angle, and better dressing effect could be obtained by deflecting the laser. The fine-grained metal diamond wheel with concave surface dressed by the deflection nanosecond pulse laser had better surface quality and profile accuracy, but there were certain metamorphic layers. Compared with the static single-section image detection (SSID), the grinding graphite plate detection (GGPD) more reflected the actual situation, and the maximum angle, arc radius and height deviation values of the 600# concave trapezoidal contour were 0.281°, 0.0049 mm, 0.0299 mm, respectively; The maximum angle, arc radius and height deviation values of the 1000# concave V-shaped contour were 0.293°, 0.0029 mm and 0.0255 mm, respectively.

Laser-assisted surface grinding of innovative superhard SiC-bonded diamond (DSiC) materials

Silicon carbide (SiC)-bonded diamond materials, comprising approximately 50% diamond by volume, represent innovative composites with exceptional mechanical and thermal properties, including high hardness, wear and corrosion resistance, and elevated thermal conductivity. Despite these advantageous properties, the machining of these composites presents formidable challenges due to their extremely high hardness. Grinding with diamond tools is commonly employed among the limited viable machining methods. However, the efficiency of this process is hindered by high grinding forces, elevated temperatures, and significantly high tool wear. Additionally, the surface integrity, form, and dimensional accuracy of the workpiece are compromised by the effects of tool wear and high cutting forces. To address these technological constraints in the grinding of SiC-bonded diamond materials, a laser-assisted grinding process has been developed. Ultra-short pulsed laser radiations were effectively utilized to induce material ablation with controlled structural damages, enhancing the productivity and efficiency of the grinding process through reduced grinding forces, temperatures, and tool wear. Furthermore, this study investigated the influence of grinding tools' specifications, design variations, and parameters on key aspects such as grinding forces, surface quality, and tool wear. Substantial reductions of up to 70% in tangential grinding forces, 83% in normal grinding forces, and a modest improvement in surface roughness achieved. The surface integrity analysis revealed a damage-free ground surface when utilizing laser assistance. Furthermore, there was a substantial enhancement in the grinding ratio (G-ratio), achieving an increase of up to 247%, concurrently with a noteworthy improvement in the actual removal depth, reaching up to 99%, when compared to conventional grinding processes. Compared to the utilized segmented metal bonded diamond grinding wheel, the vitrified bonded diamond grinding wheel induced lower grinding forces and higher actual removal rates.

Precision grinding of ceramics and ceramic-matrix composites surfaces with controllable microarray structures

The precision micro-tip truing and micro-grinding technology is proposed to process controllable microarray structures on the surfaces of ceramics and ceramic-matrix composites in this paper. It involves the mechanical truing of a metal-bonded diamond grinding wheel along V-shaped cross interpolation trajectories for creating sharp cutting edges. The trued V-tip grinding wheel was utilized to machine regular microarray structures on the surfaces of single crystal silicon carbide (SiC), silicon carbide reinforced aluminum (Al/SiCp), reaction-bonded silicon carbide (RB-SiC) and glass ceramic. The morphology of the trued grinding wheel, as well as the V-tip profile, arc radius, tip angle, form accuracy, and morphology of the ground microarray structures were analyzed. The results indicate that ground RB-SiC surface exhibits the highest processing quality, while glass ceramic has the lowest. Additionally, the errors of the bottom angle of V-grooves on all four ceramic materials are less than 1°, and form accuracy PV value is controlled within 18 µm. Overall, it is a highly efficient and accurate method for processing microarray structures on ceramics and ceramic-matrix composites.

Permeability design and assessment of the additively manufactured metal-bonded diamond grinding wheel based on TPMS structures

The development of porous metal-bonded diamond grinding wheel with excellent permeability and satisfying mechanical properties is a huge challenge for traditional manufacturing process. In this paper, a novel design and fabrication method of metal-bonded diamond grinding wheel with human-designed open porous structure is proposed based on triply periodic minimal surfaces (TPMS) and additive manufacturing (AM) process. Darcy’ law and Kozeny-Carman equation are used to calculate the permeability coefficient for the porous grinding wheel. The optimal design method of grinding wheel porous structure is proposed comprehensively considering the geometric characteristic, permeability and mechanical properties. The grinding performance of AM porous grinding wheel is evaluated by BK7 glass grinding experiment. The permeability test result proves the effectiveness of permeability design method for the novel diamond grinding wheel. The grinding test result proves the advantages of the novel diamond grinding wheel.

Microscale viscous sintering model application to the preparation of metal bonded diamond grinding wheels

During sintering, with the interfacial free energy decreasing, particles bond to each other and the dense density increases, which are familiar phenomena in the preparation of metal bond diamond wheels and affect the mechanical properties of the grinding wheel. Herein, a sintering model of metal bond diamond wheels at a microscopic scale was constructed based on the computational fluid dynamics (CFD) and discrete element method (DEM), which was carried out to reveal the flow field, pressure field, and kinetic properties of the metal material in the heating process. Meanwhile, the finite element method (FEM) was used to analyze the thermal stress of diamond particles. The results show that with the increase in temperature, the viscous flow of particles intensifies. In the middle and late stages of sintering, the porosity of the particles changes significantly, and the densification rate is accelerated. Under the same temperature conditions, compared with the dodecahedral diamond, the octahedron produces less thermal stress and has better mechanical properties.

The Fabrication of Porous Metal-Bonded Diamond Coatings Based on Low-Pressure Cold Spraying and Ni-Al Diffusion-Reaction.

A porous metal-bonded diamond grinding wheel has an excellent performance in precision grinding. In this research, a novel manufacturing process of porous metal-bonded diamond coating was presented. Firstly, the diamond/Ni/Al coatings (400–600 μm) were fabricated via low-pressure cold spraying and their microstructures were studied. The diamond particles in the feedstock had a core–shell structure. Secondly, the post-spray heat-treatments were set at 400 °C and 500 °C to produce pores in the cold-sprayed coatings via Ni-Al diffusion. The porosities of 400 °C and 500 °C heated coating were 8.8 ± 0.8% and 16.1 ± 0.7%, respectively. Finally, the wear behavior of porous heated coating was tested in contrast with cold-sprayed coating under the same condition via a ball-on-disc tribometer. The wear mechanism was revealed. The porous heated coating had better wear performance including chip space and slight clogging. The surface roughness of wear counterpart ground by the porous heated coating was smaller (Sa: 0.30 ± 0.07 μm) than that ground by cold-sprayed coating (Sa: 0.37 ± 0.09 μm). After ultrasonic clean, the average exposure height of diamond particles in the wear track of porous heated coating was 44.5% higher than that of cold-sprayed coating. The presented manufacturing process can contribute to fabricate high performance grinding wheels via cold spraying and porous structure controlling through Ni-Al diffusion–reaction.

Cavitation Effect in Ultrasonic-Assisted Electrolytic In-Process Dressing Grinding of Nanocomposite Ceramics.

Ultrasonic-assisted electrolytic in-process dressing (UA-ELID) grinding is a promising technology that uses a metal-bonded diamond grinding wheel to achieve a mirror surface finish on hard and brittle materials. In this paper, the UA-ELID grinding was applied to nanocomposite ceramic for investigating the cavitation effect on the processing performance. Firstly, the ultrasonic cavitation theory was utilized to define the cavitation threshold, collapse of cavitation bubbles, and variation of their radii. Next, the online monitoring system was designed to observe the ultrasonic cavitation under different ultrasonic amplitude for the actual UA-ELID grinding test. A strong effect of ultrasonic cavitation on the grinding wheel surface and the formed oxide film was experimentally proved. Besides, under the action of ultrasonic vibration, the dressing effect of the grinding wheel was improved, and the sharpness of grain increased by 43.2%, and the grain distribution was dramatically changed with the increase of ultrasonic amplitude. Compared with the conventional ELID (C-ELID) grinding, the average protrusion height increased by 14.2%, while the average grain spacing dropped by 21.2%. The UA-ELID grinding reduced the workpiece surface roughness Rz and Ra by 54.2% and 46.5%, respectively, and increased the surface residual compressive stress by 44.5%. The surface morphology observation revealed a change in the material removal mechanism and improvement of the surface quality by ultrasonic cavitation effect. These findings are considered instrumental in theoretical and experimental substantiation of the optimal UA-ELID grinding parameters for the processing of nanocomposite ceramics.

Influences of processing parameters on metal-bonded diamond wheel wear when grinding a sapphire wafer

Wear processes on a metal-bonded diamond grinding wheel during surface grinding of monocrystal sapphire were investigated. Through a single-factor grinding experiment, the grinding depth of the workpiece, wear from the grinding wheel, and surface roughness of the workpiece were measured and surface morphologies of the processed surface, the grinding wheel, and diamond abrasives were observed. Moreover, the mechanism of action for influences of wear of the grinding wheel on surface quality of workpiece was investigated based on a complex model of roughness when grinding in plastic and brittle modes. The results indicate that: (1) The wear process of the grinding wheel consists of four stages, i.e. slow-speed wear, high-speed wear, slow-speed wear, and stable wear; (2) With the increase of the grinding depth, the probability of plastic material removal increases by using abrasives, while workpiece surface roughness first decreases then increases; (3) Wear forms of diamond abrasives mainly include wear land at the tip and crushing of abrasives. During the grinding of sapphire wafers using a metal-bonded diamond grinding wheel, wear from the grinding wheel rises with the increase of the grinding depth. When the grinding depth is 240 μm, the surface quality of the workpiece deteriorates, so the grinding wheel needs to be dressed to restore its grinding capacity and precision.

Finite element simulation of sintering of metal-bonded grinding wheels

The grinding wheel properties porosity, particle distribution and the grain holding force influence the surface roughness of the machined workpiece and the performance of the grinding process. These properties of a grinding wheel are in turn defined during tool production. However, the adaptation of the properties of a grinding wheel to the specific grinding task is currently based on empirical knowledge and experience. Understanding the interdependencies from the initial manufacturing to the final grinding results is the key to achieve the target-oriented generation of the grinding wheel properties for the grinding task at hand. With regard to the large number of powder particles for the manufacturing of metal-bonded grinding wheels, an analytical investigation of the powder metallurgical processes is not suitable. Numerical simulations offer a cost and time saving alternative to provide information on the sintering behavior and gain knowledge on the acting mechanism. In this article the sintering of a metal-bonded diamond grinding wheel is modelled and the obtained results are connected to material properties of the resulting grinding layer.

Grinding characteristics during ultrasonic vibration assisted grinding of alumina ceramic in selected dry and MQL conditions

Ultrasonic vibration assisted grinding (UAG) has proven to lower the forces and improve the ground surface quality while shaping difficult to grind materials such as ceramics. A systematic study of UAG of alumina ceramic using a metal bonded diamond grinding wheel has been performed here. Taguchi’s L18 array based experimentation has been performed to study the effect of UAG parameters. During UAG, the vibration amplitudes of 6 and 12 microns have been used and the frequency has been kept at 20 kHz. From these experiments, optimum parameters for UAG have been identified using Grey relational analysis. Mathematical models generated using regression analysis have been found to correlate the experimental data with good accuracy. A comparison of the grinding forces and roughness of the surfaces generated in dry and minimum quantity lubrication (MQL) conditions in both conventional grinding and optimal condition in UAG has been performed to identify the beneficial effects of providing vibration to the workpiece. The surface quality has been evaluated using 3D roughness data, 3D plots and SEM images of the ground surface. By examining nature of the ground surface and kurtosis (Sku) values of the surface profile, it has been concluded that UAG reduces brittle fracture and facilitates material removal by ductile mode for alumina. The desired condition of least machining forces and highest surface quality has been achieved during the combination of UAG and MQL.

Study on formability, mechanical property and finite element modeling of 3D-printed composite for metal-bonded diamond grinding wheel application

Increasing porosity and generating expected internal structure for metal-bonded grinding wheel are the critical enabling technologies for high performance grinding wheel fabrication. Conventional hot pressing sintering (HPS) fabrication process has little capability in active formation of pore structure. In this paper, metal 3D printing technology is applied to fabricate the composite used for metal-bonded diamond grinding wheel. Through the measurement of morphological properties, mechanical properties and forming limits, the formability and performance of 3D-printed composite are evaluated. To predict the mechanical performance and understand the failure behavior, the representative volume element (RVE) model is developed for the 3D-printed metal matrix composite. And final grinding experiment indicates that 1) The 3D printing technology for composite and complicated internal structure exhibits promising potential for high performance grinding wheel fabrication with inter-connected lubrication channel and sufficient mechanical strength; 2) The 3D-printed porous wheel demonstrates sufficient durability in grinding process and superior performance in grinding capability.

Diamond abrasive based cutting tool for processing of advanced engineering materials: a review

Abstract The use of abrasives for grinding was first noticed in ancient Egypt in 2000BC. Quartz was the only abrasive known at that time. Further, emery, garnet and diamond were used as the other abrasive materials for grinding as per the need of various manufacturing processes. Diamond has been recognized as an alternate to various other available abrasive materials for grinding and finishing processes in last two decades. The machining of advanced materials such as titanium alloys, nickel alloys, heat treated steel, high strength temperature resistant alloys etc, resulted in the development of new machining processes, known as hybrid machining processes. These processes involve various new tools such as metal bonded diamond grinding wheel, diamond drill bits etc. and these are most widely accepted nowadays by the researchers in micro-machining field. In present paper, attempts have been made to do an exhaustive review of various advancements in the machining technology using the diamond abrasive based tools. Diamond abrasive tools are widely being used by various researchers in hybrid machining processes such as EDDCG, EDDFG, EDDSG, ECDG, ECDD etc. This paper illustrates the history of diamond abrasives and its use in recent advancements in the manufacturing technology till now with an overview of various manufacturing methods of the diamond abrasive based tools

Study on process and manufacturability of metal-bonded diamond grinding wheel fabricated by selective laser melting (SLM)

Selective laser melting (SLM) technology is used to fabricate metal-bonded grinding wheel based on mixed powders consisted of metal powders and diamond abrasives. Taguchi method is adopted to obtain the optimal SLM process parameters for grinding wheel considering laser power, scanning speed and layer thickness. Specimens are fabricated with different SLM process parameters for compression and three-point bending tests. Materials characterization and manufacturing limit test are performed on the specimens fabricated by the optimal SLM process. Results indicate that laser power of 250W, scanning speed of 2.5m/s and layer thickness of 20μm are determined as the optimal SLM process in terms of comprehensive mechanical property and formed surface quality. Moreover, diamond abrasives are firmly embedded into aluminium binder with good bonding condition for SLM-fabricated composite. Furthermore, manufacturability of SLM-fabricated composite is evaluated by manufacturing limits of several common structures. In summary, work in this study fully proves the feasibility of SLM-fabricated metal-bonded grinding wheel and provides a solid basis for the further investigation on the novel grinding wheel with customized porous structures.

The effect of porosity on the mechanical property of metal-bonded diamond grinding wheel fabricated by selective laser melting (SLM)

Selective laser melting (SLM) technology is applied to fabricate grinding wheel with high porosity and controllable porous structure. Octahedron cellular structures with porosities ranging from 0.3 to 0.7 and AlSi10Mg/diamond composite are fabricated and investigated in terms of morphological properties and mechanical properties. Characterizations of cellular structure, grain-bond interface and practical porosity are performed. Compression test and three-point bending test are carried out to study the effect of porosity on mechanical property of grinding wheel. The results show that metallurgical bonding forms at the grain-bond interface for the SLM-fabricated composite. The compressive characteristics conform to the classic Gibson-Ashby model for stretch-dominated cellular structure and have positive correlation and linear relationship with relative density. Flexural strength is linear with relative density while flexural modulus is non-linear with relative density. The specimen shape changes from cube to prism, barrel or cuboid during compression test corresponding to three different failure modes. The initial crack always generates in the middle region of specimen and propagates from bottom to top till absolute fracture during three-point bending test. The deformation behavior of SLM-fabricated porous composite resembles to brittle material.

Porous structure design and fabrication of metal-bonded diamond grinding wheel based on selective laser melting (SLM)

High porosity will bring about a great deal of contributions for metal-bonded grinding wheels. In this research, cellular structures, including octahedron, truncated octahedron, and stellated octahedron, are chosen as porous structures for a grinding wheel and fabricated using selective laser melting (SLM) with diamond/AlSi10Mg mixed powders. Moreover, the microstructure and bonding condition of SLM-fabricated composite are investigated. Additionally, morphological properties, mechanical properties, and permeability of three different porous structures are studied and compared with each other based on experiment and simulation. It is revealed that the microstructure of SLM-fabricated composite exhibits anisotropic due to the layered manufacturing essence. Furthermore, the cladding state of diamond grits is good and strong interface forms between diamond and AlSi10Mg. Besides, both mechanical performance and permeability of octahedron structure are the best, making it a potential structure for a high-performance porous grinding wheel.

Study on design and performance of metal-bonded diamond grinding wheels fabricated by selective laser melting (SLM)

Porous metal-bonded grinding wheels with high porosity and controllable pore shape, size, quantity and distribution are in great demand but hard to realize for traditional process. In this study, the novel method is proposed to fabricate porous metal-bonded grinding wheels based on selective laser melting technology. Three kinds of grinding wheels, including octahedron structure wheel, honeycomb structure wheel and solid structure wheel, are designed and fabricated using this novel method. Additionally, morphological characterization is conducted in terms of porous structure, microstructure and bonding condition. Furthermore, grinding performance is evaluated in terms of grinding force, material removal rate, ground surface roughness and hardness. Experimental results indicate that the SLM-fabricated grinding wheels possess the excellent dressing and self-sharpening ability, good bonding strength, controllable pore structure, high porosity and good comprehensive grinding performance. Compared with electroplated wheel, better machined surface roughness and slighter work hardening can be achieved by the SLM-fabricated wheels based on the similar material removal capacity. Among the SLM-fabricated wheels, octahedron structure wheel possesses the smallest extrusion and friction force, the highest instantaneous cutting force and the slightest work hardening, and solid structure wheel possesses the largest material removal rate.

A novel technique for dressing metal-bonded diamond grinding wheel with abrasive waterjet and touch truing

The dressing of metal-bonded diamond grinding wheels is difficult despite their availabilities on hard and brittle materials. In this paper, a novel compound technology that combines abrasive waterjet (AWJ) and touch truing is proposed for dressing metal-bonded diamond grinding wheel precisely and efficiently. The dressing experiments of a coarse-grained and a fine-grained bronze-bonded diamond grinding wheel were carried out on a surface grinder with a developed AWJ system. The feasibility of this method was verified by analyzing the wheel runout, the truing forces, and the wheel surface topography. The variations of 3D surface roughness of wheel surface topography during the compound dressing process were quantitatively analyzed. The mechanism of AWJ and touch compound dressing is also discussed. Further, a reaction-bonded silicon carbide block was ground to validate the dressing quality. The experiment results indicate that the grinding wheels that were well dressed by the proposed technique leads to a smaller grinding force and a smaller surface roughness than that of undressed wheels.

Defects in diamonds as the basic adhesion grinding

Defects arising in diamond crystals during their synthesis, give rise to the formation of more complex defects that arise in the operational process of diamonds themselves. In case of external action these defects have immediate strong effect on operating characteristics of devices, products or tools containing diamonds. When external action these defects and have immediate strong effect on production characteristics of devices, products or instruments containing diamonds. This is particularly manifested in the grinding of tough, ductile materials based on aluminum, magnesium or titanium. Developed on the basis of modern digital technology and molecular dynamics visualization method allows to show it at the atomic level. The problems of practical application of the combined electric diamond grinding are examined. Experiments were conducted on the grinding tool materials with metal-bonded diamond grinding wheels.

Laser-Profiling of Metal-Bonded Diamond Grinding Wheels

Conditioning challenges of superabrasive grinding wheels cause a barrier to the extensive applications of these tools. These concerns are more pronounced in the case of conditioning of metal-bonded superabrasive grinding wheels owing to their high bond hardness. Laser ablation has been used as a promising method for conditioning of such tools. In this research an ultrashort pulsed laser was used for efficient profiling of metal-bonded diamond grinding wheels. In order to assess the laser-profiling technique, the experiments were aimed to generate precise profiles which are rather too difficult or impossible to generate with conventional methods. Convex and concave profiles with minimum radius of about 20 μm and 40 μm, respectively are produced successfully via laser conditioning.

Electrical Discharge Dressing (EDD) of Metal Bonded Diamond Arc Grinding Wheels

Metal bonded diamond grinding wheels are very important for precision grinding operations of hard and brittle materials especially like ceramics or cemented carbides. But the trueing and dressing problem has affected its wide use. In this paper, a new EDD (Electrical discharge dressing) device was developed for the dressing of metal bonded diamond arc grinding wheels. The EDD experiments were carried out with the new dressing device. The influence of dressing parameters on the dressing efficiency and precision was studied. Experimental results shown that the increase of pulse period and duty period helped improve the dressing efficiency in a certain range. The higher electrical parameters could get better dressing efficiency. The detection results revealed that the error of the arc profile after EDD could reach to around 3μm. mazhaokai2014