Resin-bonded Diamond Grinding Wheel Research Articles

Effect of the grinding process on the surface quality of ultrafine cemented carbide with different Co content

By using a resin bonded diamond grinding wheel, the influence of grinding conditions on processing quality of the ultrafine cemented carbides with different Co content were investigated. Through grinding experiments, the effects of grinding wheel linear speed, feed speed and grinding depth on the surface morphology, roughness, and residual stress of cemented carbides were studied, and the relationship between grinding conditions and machining quality was established. Then, the evaluation and prediction of surface quality according to the grinding parameters can be realized by using ternary regression analysis. Finally, gray relational analysis was applied to optimize the multi-objective concerning surface quality to find the optimal grinding process parameters. The grinding test results show that with the increase of grinding linear speed as well as the decrease of feed speed and grinding depth, the maximum undeformed abrasive particle thickness decreases, which improves the surface plastic removal ratio and reduces the surface roughness. The multi-objective optimization of the grinding process can be achieved by using gray relational analysis, the resulting optimal process parameters achieve the lowest residual stress and surface roughness, which provides a theoretical basis for the prediction and control of the surface quality of cemented carbide in the grinding process.

Analysis of large edge breakage of WC-Co cemented carbide tool blades emerging in precision grinding process

This paper analyzes the edge damage characteristics of the cutting blade made of WC-Co cemented carbide material after precision grinding. The edge damage characteristics present tiny cracks and serrated continuous edge breakage. The main causes of the edge damage were explored regarding the edge residual stress, microstructure, and the change of element content. The results show that the value of the average residual compressive stress on the rear surface of the caving edge is −1745.7 MPa, which is much larger than that recorded before grinding (−578.6 MPa). The content of element C and element W on the surface increased obviously (from 28.35% to 34.29% and 54.51%–61.06% respectively). The increase of WC grains and the decrease of Co content will lead to the decrease of the bonding strength of the corresponding material, which will easily lead to the crack at the edge and cave. The grinding experiment of WC-Co cemented carbide was carried out with a bowl shape resin-bonded diamond grinding wheel and was optimized with the orthogonal experimental method. The optimized results show that the single grinding amount was the biggest factor affecting the processing time. The angular speed of rotation and the single grinding amount was listed as the factors that had the greatest influence on the blade rejection rate. Considering the processing efficiency and quality comprehensively, adopting the improved combination during the grinding process, the experimental results were as follows the blade rejection rate is 10%, and the processing time of a single blade is 205 s.

Effect of Graphene Nanoplatelets Reinforcement on Grindability of Zirconium Diboride Ceramics

Abstract The effect of graphene nanoplatelets (GNPS) on the grindability of GNP reinforced ZrB2 was studied using a resin bonded diamond grinding wheel under dry and wet conditions. A comparative study of grinding forces was performed at selected wheel surface speeds and depths of cut for surface grinding. ZrB2-GNP showed lower normal grinding forces due to the improved fracture toughness and reduced hardness. The presence of GNP reinforcement in ZrB2 resulted in lower tangential forces and reduced specific grinding energy due to the role of GNP as a solid lubricant. The measured forces showed a good correlation with the micro cutting model for ZrB2 and ZrB2-GNP under dry conditions. The tangential forces showed the same trend as normal forces at different depths of cut and wheel surface speeds for ZrB2 and ZrB2-GNP with average force ratios of 0.3 and 0.35, respectively. The presence of porosity in ZrB2 increased the normal grinding forces during wet grinding. Scanning electron microscope (SEM) images of the grinding chips indicated a mixture of both the ductile mode and the brittle mode of material removal with predominantly brittle fractured chips. Energy-dispersive spectroscopy (EDS) confirmed the presence of GNPs in ZrB2-GNP grinding chips. The topography of the grinding wheel showed higher wheel loading after the dry grinding than that of wet grinding. The wet grinding resulted in relatively lower surface roughness (Ra values) than dry grinding.

Grinding efficiency and profile accuracy of diamond grinding wheels dressed with wire electrical discharge conditioning (WEDC)

Super abrasive diamond grinding wheels are the most promising tools for the precision machining of advanced ceramics and carbide materials. However, the efficiency of conventional conditioning of these tools is limited owing to high dressing tool wear, long process time, low form flexibility, and induced damage to the abrasive grains. Wire electrical discharge machining (WEDM) is an alternative method for conditioning of superabrasive grinding wheels with electrically conductive bonding materials. In this study, cylindrical plunge grinding of an alumina ceramic with a resin-bonded diamond grinding wheel is investigated. The assigned type of resin bond contains copper particles and is accordingly electrically conductive for wire electrical discharge conditioning (WEDC). Conventional (mechanical) and WEDC methods are used for generating the same profile on two similar diamond grinding wheels. As a result, the specific grinding energy was reduced up to 26% and 29% during rough and finish plunge grinding, respectively. Reduced specific grinding energy and forces, along with more effective grain protrusion and sharpness by using WEDC for profiling of grinding wheels, have contributed positively to the ground surface conditions despite the relatively rougher wheel surface topography in comparison to the conventional profiling. The more considerable reduction in the mean roughness depth (Rz) than in the arithmetical mean roughness value (Ra) (11% smaller Rz values in WEDC versus mechanical conditioning) verifies that the workpiece surface underwent less surface degradation in case of WEDC because of smaller grinding forces. Furthermore, the profile wear behavior of the workpiece ground with the WED conditioned grinding wheel was superior to the conventionally conditioned one.

Laser dressing of arc-shaped resin-bonded diamond grinding wheels

Laser dressing technology is expected to solve the dressing problem of superabrasive forming grinding wheels. However, this technology is still in the initial stage of research, and is facing bottlenecks such as poor profiling accuracy due to the difficulty of tool setting of laser beam, uncontrolled sharpening topography due to laser focus characteristics, and reduced grain performance due to ablation thermal damage. In this paper, the research on laser dressing of arc-shaped resin-bonded diamond grinding wheel with a grain size of about 180 μm was systematically carried out. Acoustic emission monitoring technology was first introduced into laser dressing, which solved the problem of low accuracy of tool setting of laser beam. The laser tangential profiling method based on deep cutting and intermittent feeding was improved to achieve efficient and precise profiling of arc-shaped grinding wheels. It took about 4.5 h to profile a parallel grinding wheel into an arc-shaped grinding wheel. Limited by the accuracy of the experimental device, the surface contour accuracy of the arc-shaped grinding wheel after profiling was currently only about 20 μm. It was found that the grains in the middle area of the surface of the grinding wheel were only slightly graphitized, and the damage degree of the grains in the edge area was more serious. A new method of laser sharpening based on layered scanning was proposed, which effectively reduced the difficulty of controlling the laser scanning trajectory, and achieved the uniform removal of the bond and the precise control of the grain protrusion height everywhere on the surface of the grinding wheel. It was found that the laser beam did not damage the diamond grains during the sharpening process. Compared with that before sharpening, the proportion of C and O elements in the resin bond after sharpening increased by about 5.7 % and decreased by about 5.0 %, respectively.

Analysis of the Grinding Characteristics of β-Ga2O3 Crystal on Different Planes

The (010) and (100) planes of a [Formula: see text]-Ga2O3 crystal were subjected to precision grinding tests with a resin bond diamond grinding wheel on a precision surface grinding machine. The grinding characteristics and surface grinding quality of the planes of the [Formula: see text]-Ga2O3 crystal were analyzed on the basis of grinding force, grinding force ratio, specific energy, and surface morphology. The (010) plane shows a larger grinding force and specific energy but a smaller grinding force ratio compared with the (100) plane. Under experimental conditions, the normal and tangential grinding forces of the (010) plane are 1.4–2.2 and 2.6–7.8 times that of the (100) plane, respectively. The specific energy of the (010) plane is 2.8–6.1 times that of the (100) plane, and the grinding force ratio of the (100) plane is 1.4–3.7 times that of the (010) plane. Under the same grinding conditions, the material removal methods for the two planes are evidently different. The (010) plane is mainly removed by brittle fracture and accompanied by a minimal broken area, whereas the (100) plane is mainly removed by cleavage layering and exhibits numerous block cleavage. The (100) plane is the strong cleavage surface, and the (100) plane demonstrates a higher surface roughness than the (010) plane under the same grinding conditions.

Developing a novel binderless diamond grinding wheel with femtosecond laser ablation and evaluating its performance in grinding soft and brittle materials

In this study, a binderless diamond grinding wheel (BDGW) is fabricated to prevent impurities embedding during the machining of soft and brittle materials by conventional grinding wheels. The ‘binder’ features, as well as the ‘grains’, are produced on a single piece of chemical vapor deposition diamond, whilst the ‘grains’ are ablated with a femtosecond laser. The performance of the novel grinding tool in terms of grinding radio, wear types, grinding forces and specific grinding energy, ground surface roughness, surface morphology, and subsurface damage is evaluated by comparing it with a resin-bonded diamond grinding wheel (RDGW). Experimental results show that the BDGW has excellent redress life with simple form of wear-abrasion wear on the top of the cutting edges and extremely high grinding radio of 103, which is nearly eight times of that of the RDGW. The benefit of the simple form of BDGW wear is that no embedded bond debris and fall-off grains appear. These conditions are essential to ensuring high ground surface quality for grinding soft and brittle materials.

Selective laser sintering and grinding performance of resin bond diamond grinding wheels with arrayed internal cooling holes

In this study, selective laser sintering was used to 3D print resin bond diamond grinding wheels with internal cooling holes. The mechanical properties and microstructures of the resin bond diamond grinding wheel were investigated. The grinding performance of 3D printed resin bond diamond grinding wheels with different internal cooling holes on the glass and cemented tungsten carbide was examined. The results show that 3D printed resin bond diamond wheels can be used to grind the glass and cemented tungsten carbide. Wheels containing internal cooling holes have lower grinding force. With increasing number and diameter of internal cooling holes, grinding forces on the glass decreased. Surface roughness up to 2–4 μm on the glass and cemented carbide was obtained by present 3D printed resin bond diamond wheel.

Realization of high efficiency and low damage machining of anisotropic KDP crystal by grinding

Potassium dihydrogen phosphate (KDP) is a non-linear material used in various opto-electronic applications including Q-switches, high-speed photography shutters, frequency harmonic generation lens and Pockels cells in the Inertial Confinement Fusion (ICF) devices. KDP belongs to the most difficult-to-cut material, due to its delicate and unique characteristics including the combination of softness with brittleness, anisotropic performances, tendency for deliquescence and sensitivity to temperature change. Single point diamond turning (SPDT) is considered to be the ideal method for machining KDP components. However, the process efficiency is rather low and often accompanied with severe tool wear issues. This paper studies the feasibility using grinding method to remove the surface material of KDP components with high process efficiency and low damage, fulfilling the task of re-aligning the surface orientation to the crystalline axis. The grinding tests were carried out on a common CNC grinder, using resin bonded diamond grinding wheel, whilst the diamond abrasives are coated with Ni-P alloy. The direction of precision grinding was determined by studying the anisotropy of KDP, including its elastic modulus E, Vickers hardness HV and fracture toughness KIC, to reduce the influence of material anisotropy on machining quality. The grinding process parameters were preliminarily determined based on the experimental results investigating the effects of peripheral speed of the grinding wheel, worktable feed rate and grinding depth on the ground surface roughness. The surface defects, surface morphology and sub-surface damage under different process parameters were investigated. Surface roughness Ra ≤ 0.3 μm and sub-surface damage depth SSD ≤ 6 μm were obtained. The machining efficiency can be improved by nearly ten times using the proposed precision grinding method, producing nearly the same surface quality (Ra ≤ 0.2 μm, SSD ≤ 6 μm) as that in the axis fixing phase in SPDT.

Grinding of WC-Co cermets using hexagonal boron nitride nano-aerosol

WC-Co cermets (ceramic-metal composites) were ground by a resin bonded diamond grinding wheel using hexagonal boron nitride (hBN) nano-aerosol to improve the grindability. This is a new generation grinding fluid and was produced by dispersing nano-sized hBN platelets in deionized water. Small quantity cooling-lubrication (SQCL) technology was employed to deliver hBN nanofluid in the form of nano-aerosol so that volumetric consumption rate could be kept at a very low value of 200 ml/h. The nanofluid, when separately characterized, demonstrated good lubrication and heat dissipation capability in reference with soluble oil, which is a commonly used cutting fluid for grinding. The superior tribological characteristics of hBN nanofluid were more pronounced at a high sliding speed of 1 m/s, as observed during a ball-on-disc test. However, the beneficial effect of using hBN nanofluid could be extracted more efficiently only in aggressive grinding condition. A clear drop in specific energy, favourable values of residual stress indicate the same. Prevalence of low grinding zone temperature was reflected through low specific energy values and finer but complex chip micromorphology. Overall the aqueous hBN nanofluid was proven to be a high performing grinding fluid suitable for SQCL application and WC-Co cermet grinding.

Research on GC Cup Truing Technology of Super-Hard Grinding Wheel

In this paper, the GC cup truing technology on resin bond diamond grinding wheel is studied, and the parameters of truing the diamond grinding wheel process are optimized. Also the contour accuracy and microscopic topography of the diamond grinding wheel are analyzed quantitatively. Besides, the method of evaluating the dressing effect of diamond grinding with the roughness of grinding wheel is proposed.

Correlation between surface roughness and AE signals in ceramic grinding based on spectral analysis

The study and monitoring of the workpiece surface roughness is one of the most important parameters of the grinding process. This paper proposes a method for analysing the surface condition of ground ceramic components by means of the acoustic emission (AE) signal analysis along with frequency domain techniques. Tests were performed using a surface-grinding machine equipped with a resin-bond diamond grinding wheel, where signals were collected at 2 MHz. Alumina workpieces were machined under six different depth of cut values, covering slight, medium and severe grinding conditions. Frequency content was studied in order to select bands closely related to the process conditions. An analysis of the root mean square values (RMS) of the signals was performed, seeking for a correlation with the surface roughness. Digital filters were applied to the raw signals. The RMS values filtered for two frequency bands presented a better fitting to the linear regression, which is highly desirable for setting a threshold to detect the workpiece surface conditions and implementing into a monitoring system. Results showed that the amplitude of the signals presented different characteristics in the frequency domain according to the workpiece surface condition. It was also observed a higher spectral activity in the severe grinding conditions.

Grinding characteristics of cBN-WC-10Co composites

In order to explore the grinding characteristics of cBN-WC-10Co composites, the grinding experiment with a resin bond diamond grinding wheel was carried out. The grinding forces, surface roughness, surface morphology and residual stress were investigated. It was found that the material removal mechanism of cBN-WC-10Co was the combination of the brittle fracture of cBN particles, ductile removal of Co phase, plastic deformation, grain dislodgement and grain crush of WC grains. The brittle removal model resulted in a lower specific grinding energy. The main contributor to the surface roughness was cBN particles. Some cBN particles over the surface of cBN-WC-10Co composites were fractured or pulled out and then formed cavities with different depths, this led to a rougher surface. The surface roughness was increased but the specific grinding energy decreased with an increase of the maximum undeformed chip thickness. A high-level residual compressive stress was induced at WC phase and it was increased with an increase of the depth of cut. The depth of cut has more significant influence on the grinding forces than the table speed or the wheel speed.

Study on grinding of pre-sintered zirconia using diamond wheel

ABSTRACTZirconia-based ceramics are the most preferred materials used in implants due to their excellent mechanical properties compared with other alternatives. These materials available in the pre-sintered form are appropriate to grind due to their soft nature. However, it is challenging to achieve a required surface finish in grinding these ceramic materials owing to chipping, which limits its usage in industries. In this work, the pre-sintered yttria stabilized tetragonal zirconia (Y-TZP) component was ground using a resin-bonded diamond-grinding wheel under different cooling environments. The components ground under the minimum quantity lubrication conditions exhibited a reduced grinding force with better surface finish compared to wet (flood coolant) and dry conditions. The resultant specific energy was reduced with the increase in maximum chip thickness for different cooling conditions. The critical depth of cut estimated from the pre-sintered zirconia was witnessed to be higher, which indicated that the initiation of ductile to brittle transition occurred at a deeper depth of cut. The material removal mechanism observed in the pre-sintered zirconia was dominated by brittle fracture. This was evident from the obtained chips and ground surface morphology.

A study on the surface grinding of 2D C/SiC composites

This paper aims at studying the machinability of 2D C/SiC composite with 0°/90° woven carbon fibers using a resin bond diamond grinding wheel. The effects of grinding parameters on the grinding force, force ratio, specific grinding energy, surface topography, surface roughness, and grinding chips were investigated. And the grinding mechanism of the 2D C/SiC composite was discussed by analyzing the chip components and material removal characteristics. The results indicate that the grinding force and surface roughness increase with the increase of feeding speed and depth of cut, while decrease with the increase of wheel speed. The force ratio F n /F t and the specific grinding energy of 2D C/SiC composite were lower than those of conventional ceramics under the defined experimental conditions. Additionally, the grinding chips were composed of carbon powder, carbon fiber fragments, and SiC matrix debris. It can be deduced that the dominant removal mechanism of the 2D C/SiC composite was brittle fracture mode during grinding process.

Investigation of Grinding Characteristics of Cemented Carbides YL10.2 and YF06

YL10.2 and YF06 are ultrafine-grained cemented carbides, and grinding experiments were carried out with resin-bonded diamond grinding wheel. Based on measured grinding force, surface roughness and SEM topography, experimental results were analyzed; grinding forces and depth of grinding approach linear correlation; and the grinding force of YF06 is greater than that of YL10.2 in rough grinding, but the grinding force increases significantly if depth of cut is greater than a certain value in finish grinding. The trend of machined surface roughness looks like “V” type with the increasing of depth of cut; the material removal behavior of ultrafine-grained cemented carbides in grinding was observed; the ploughing and fragmentation exist simultaneously on the ground surface, and the dominated material removal behavior depends on the grinding parameters or chemical composition of workpiece.

Research on Grinding Temperature of a New Diamond Grinding Wheel

It is aimed at developing a new diamond wheel in order to overcome the shortages of traditional grinding wheel, such as the abrasive easily fall off the grinding wheel prematurely, high grinding temperature, random grits distribution and the loading problems become more severe in grinding process. And further study on the grinding temperature of the new diamond wheel prepared in comparison with traditional resin-bonded diamond grinding wheel in machining Al2O3 ceramic. The prepared new diamond wheel has many diamond fibers involved in grinding process which are artificially ordered, diamond grits are not easily fall off, and it has big chip-pocket space and heat dissipating capability. The experimental results indicated that the grinding temperature of the new diamond wheel in comparison with the conventional diamond wheel under the same conditions was decreased by 80°C-120°C.

Precision Grinding Characteristics and Process Optimization on YG3 Cemented Carbide

Precision grinding experiment and process optimization of YG3 cemented carbide materials was conducted with various grinding parameters using resin-bonded diamond grinding wheel. Different rotation speed of workpiece, feed rate and grinding depth were chozen in precision cross grinding. Surface roughness was measured for studying the removal mode and grinding charateristics. A set of ideal grinding parameters of YG3 cemented carbide were obtained by changing the process parameters. The research result has guiding significance for reducing the wheel wear and processing costs, improving grinding quality and efficiency while precision grinding hard and brittle materials.

Influence of Pore-Forming Agent on the Performance of Resin Bond Diamond Grinding Wheel in Back-Grinding Silicon Wafers

Back grinding is the key working procedure in the silicon wafer manufacturing process. Ground silicon wafers ought to have low subsurface damage layer thickness (SSD ) and surface roughness value. It requires that the wheel should have high self-sharpening ability and consistent performance. In this paper, the research on pore-forming agent in order to improve the wheel’s self-sharpening ability of the resin-bond diamond grinding was conducted. The research includes the pore-forming mechanism of various pore-forming agent, the influence of pore-forming agent’s type and the effect on the bond’s strength, the influence of pore-forming agent on the grinding performance of the wheel. Moreover, it examines the improved grinding wheel’s grinding effect by grinding tests.

A new two-dimensional ultrasonic assisted grinding (2D-UAG) method and its fundamental performance in monocrystal silicon machining

A new two-dimensional (i.e., elliptical) ultrasonic assisted grinding (UAG) technique is proposed to achieve high material removal rate and high surface quality in the machining of hard and brittle materials such as monocrystal silicon. In this method, the workpiece attached on an elliptical ultrasonic vibrator is ground with a resin bond diamond grinding wheel under the presence of elliptical ultrasonic vibration. The elliptical ultrasonic vibrator is produced by bonding a piezoelectric ceramic device (PZT) on a metal elastic body (stainless steel, SUS304) and its detailed structure/dimensions are determined by FEM (finite element method) analysis. When two alternating current voltages with a phase difference are applied to the PZT at the same frequency that is close to the resonant frequency of the longitudinal mode and bending mode of vibrator, two ultrasonic vibrations are generated simultaneously, and the synthesis of the vibrations results in an elliptical motion on the end face of the vibrator. If the phase difference is set at 0° or 180°, two kinds of one-dimensional ultrasonic vibrations, i.e., axial or vertical vibrations, can be obtained. Grinding experiments are carried out involving monocrystal silicon to confirm the performance of the proposed elliptical UAG. In addition, grinding experiments under the presence of the axial and vertical ultrasonic vibrations and the absence of ultrasonic vibrations, i.e., conventional grinding, are also carried out for comparison. The obtained results show that: (1) compared with conventional grinding, the axial ultrasonic vibration results in greatest improvement in the work surface quality and a slight reduction in the grinding forces; (2) under the vertical ultrasonic vibration, the grinding forces are decreased significantly but the surface roughness is increased slightly; (3) elliptical ultrasonic vibration leads to the significant reduction of both the surface roughness and grinding forces. These indicate that the high efficiency and high-quality grinding of monocrystal silicon can be performed with the proposed two-dimensional ultrasonic assisted grinding technique.