Resin-bonded Diamond Wheel Research Articles

Novel surface characteristics observed during grinding of polycrystalline diamond

The use of diamond is ubiquitous in many engineering applications, yet its processing by conventional machining methods continues to pose challenges owing to its extreme hardness and chemical inertness. Grinding polycrystalline diamond workpieces is a viable commercial method used to obtain nanometric smooth and damage-free surfaces. In light of the novel experimentation work, this study shed light on the fundamental material challenges encountered during the nanoscale grinding of polycrystalline diamonds with resin-bonded diamond wheels. The experimental results revealed a strong influence of the grain orientation in affecting the paradigm of the material removal such that a particular orientation of diamond showed some “ripple” like surface structures that could not be smoothed even using the post-grinding plasma operation. The in-situ experimental analysis as well as the complementary molecular dynamics simulations involving the use of a long-range Screening bond order potential function offered new insights into the mechanism of “ripple formation” and CC bonds observed on the (110) oriented diamond surface. Furthermore, in-situ observation experiments revealed that the ripple-like structure followed periodic recurrence, suggesting that the material removal rate during the process of grinding is influenced periodically in a recurring manner.

Experimental research on wear mechanism of diamond wheels for grinding Cf/SiC composites grooves

Aiming at the problems of low processing efficiency, low groove shape accuracy and poor surface quality caused by grinding wheel wear in the grinding process of Cf/SiC composite grooves. In this paper, based on the motion mode of grinding wheel grinding, the wear volume formula of grinding wheels was analyzed, and the grinding wheel wear comparison experiment of different bond diamond grinding wheels grinding Cf/SiC composite grooves was carried out, and the more suitable kind of diamond grinding wheel for grinding Cf/SiC composite grooves was selected. From the experimental results, compared with the ceramic-bonded diamond wheel and resin-bonded diamond wheel, the grinding times of electroplated diamond wheel grinding Cf/SiC composites were increased by 20 and 104, respectively, and the surface roughness of the groove was most stable and the processing damage was smallest. Therefore, the best quality of grinding Cf/SiC composites groove was obtained by the electroplated diamond grinding wheel, and its life in grinding Cf/SiC composites was the longest. At the same time, the wear mechanism of the electroplated grinding wheel was explored, the wear on the bottom surface of the electroplated grinding wheel was more serious than that on the circumferential surface. The wear on the bottom surface was mainly wear and tear, and it gradually diffused along the inner diameter of the grinding wheel with the increasing grinding times.

Wear-induced variation of surface roughness in grinding 2.5D Cf/SiC composites

As the ideal high-temperature component materials, Cf/SiC composites require high grinding surface quality for their final preparation. It is a challenging issue to achieve the desired surface quality of such hard brittle material with serious rapid tool wear. A surface roughness predictive model involving the grinding wheel cumulative wear was developed for grinding process of 2.5D needled Cf/SiC composites. Compared with the experimental data, the predicted ground surface roughness errors of 2.5D needled Cf/SiC composites are less than 12 %. It is found that due to the grinding wheel cumulative wear effects, the resin-bonded diamond wheel presented self-sharpening phenomenon as increasing specific material removal volume (SMRV). The grinding wheel cumulative wear effects are conducive to Cf/SiC ground surface improvement. When the SMRV reached 720 mm3/mm, the surface roughness decreased by 21.2 % with a 180# grinding wheel, and 8.6 % with a 280# grinding wheel. This work provides some insights for preparing the tool condition during grinding 2.5D needled Cf/SiC composites.

Effect of surface topography of fiber laser dressed resin-bond diamond wheel on its grinding performance

Effect of surface topography of fiber laser dressed resin-bond diamond wheel on its grinding performance

Wafer-Scale Polishing of Polycrystalline MPACVD-Diamond

Diamond offers great potential for use as a thermal spreader in various applications, including power electronics and radio-frequency (RF) applications. However, to be used as an efficient thermal spreader, the atomically smooth surface of the diamond is critical to be bonded with chips. Herein, a polishing technique for a 2-inch diameter wafer-scale bulk polycrystalline diamond substrate is proposed. In this work, 350 μm thick polycrystalline diamond is grown by the microwave plasma-assisted chemical vapor deposition (MPACVD) technique on a Si substrate at a growth rate of 8 µm/h. Thereafter, a three-step polishing process was applied to achieve an atomically smooth surface, consisting of grinding using a diamond slurry with an iron plate, ICP etching using the SF6 gas, and final mechanical polishing using a resin-bonded diamond wheel. Surface roughness of diamond characterized by atomic force microscopy showed the significantly reduced from 900 nm to 0.3 nm. Hence, this study provide the practical methods for obtaining atomically smooth diamond films suitable for thermal management in various areas including power electronics and RF devices.

Ultra-precision raster grinding of monocrystalline silicon biconical free-form optics using arc-shaped diamond grinding wheels

Free-form optics are becoming increasingly indispensible in a series of industries, such as aviation, aerospace, medical, digital video and audio optoelectronics, owing to its enhanced optical performance, fewer surfaces, lower mass, lower cost, smaller package-size and reduced stray-light, etc. However, the ultra-precision machining of free-form surface optics, especially the non-rotational asymmetric free-form optics is still faces a great challenge. In this study, ultra-precision grinding of the non-rotational asymmetric biconical free-form optics with raster grinding path was studied. Firstly, a novel feeding compensation truing strategy for truing the arc-shape grinding wheels with high-precision was proposed. A D46 μm metal-bonded grinding wheel and a D7μm resin-bonded diamond wheel, were successfully trued with high profile accuracy and desired surface topography. Subsequently, the influence of the significant grinding factors like grinding path, scallop height, contact arc length and the grinding wheel wear on the ground profile accuracy and surface quality of the biconical free-form optics was theoretically and and experimentally analyzed. Eventually, a larger size monocrystalline silicon biconical free-form optics with profile accuracy 6.0 μm and nanometer surface roughness was successfully manufactured by raster grinding combined the technology introduced in this paper.

Electrochemical cleaning grinding (ECCG) of aluminum alloy 6061 with electroconductive resin-bonded diamond wheels

A new manufacturing process named Electrochemical Cleaning Grinding (ECCG) is introduced to help reduce wheel loading in grinding of the highly ductile metals which exhibit high adhesion tendency. The key component of the ECCG system is an electroconductive resin-bonded diamond wheel, and its abrasive layer is made of phenolic resin bond and core-shell structured Ni-P alloy coated diamond abrasives. The alloy coating over diamond grains not only helps to increase the bond strength between the resin and the abrasives but improve the electrical conductivity properties of the grinding wheel. During the ECCG process, the abrasives on the wheel surface simultaneously act as micro cutting edges as well as microelectrodes where the anodic dissolution of the adherent metal materials takes place. This dissolution process is defined as “cleaning”. When the rate of accretion of adherent material is balanced by its electrochemical dissolution rate, the sharp abrasives are exposed to carry out efficient grinding, so that better grinding performance can be achieved. The grinding experiments of aluminum alloy 6061 (AA6061) were conducted to verify the effectiveness of the ECCG process. Compared with conventional grinding experiments, the most important changes brought in by the ECCG are the decrease in wheel loading degree and the improvement in machined surface quality. Additionally the electric energy consumption of the cleaning process is relative low and equal from 1.88 × 10−3 J/mm3 to 9.34 × 10-3 J/mm3.

Arc Envelope Grinding of Sapphire Steep Aspheric Surface with SiC-Reinforced Resin-Bonded Diamond Wheel

In order to improve the grinding wheel wear during the sapphire steep aspheric surface grinding process, a SiC-reinforced resin-bonded hemispherical diamond wheel was used and the arc envelope grinding performance was investigated. Firstly, the mapping relationship between the contours of the grinding wheel and the aspheric surface was established based on the grinding conditions. The wear of the hemispherical diamond wheel was modelled, and the result indicates that the maximum wear occurred at the edge of the hemisphere, decreases along the generatrix and increases near the center. Then, the form-trued diamond wheel was used for grinding the sapphire steep aspheric surface. The concave and convex surface form error obtained at the central part of Φ 50 mm are 2.5 μm and 1.3 μm, respectively. The surface roughness Ra is 230–450 nm, which is affected by the material removal rate and the sapphire crystal anisotropy. The SiC-reinforced resin-bonded diamond wheel possesses favorable self-sharpening ability and sufficient diamond grain retention capacity for sapphire grinding. The wear distribution shows that the most severe wear parts of the grinding wheel are at the edge and the center of the grinding zone, which is consistent with the model-predicted results.

Thermal damage control for dry grinding of MgO/CeO2 glass ceramic

MgO/CeO2 glass ceramic is a key solid catalyst and accelerant produced by raw mixing, prilling and pressure sintering. Grinding, as a high-efficiency machining method was used to obtain MgO/CeO2 glass ceramic components with accurate size to meet the size requirements of design. However, thermal damage occurring on the ground surface may change the properties of the components and affect their performance in subsequent applications. In this work, a grinding thermal model was established and validated by experiments. On the basis of this thermal model, the grinding temperature can be controlled to < 100 °C by selecting optimal grinding parameters and thus prevent grinding burn. The mechanism of potential chemical reactions on the grinding surface was further studied by analysing the transient temperature jump at a grain wear flat area and comparing the change in element mass fraction before and after grinding. The performance of a normal resin bond diamond wheel and a resin bond wheel with Ni–P alloy coating on the diamond grains was compared. Results showed that the latter intensified the redox reaction because of the catalytic actions of Ni and P, and the mass fraction of each elements on the workpiece surface shows obvious uneven distribution due to the surface spalling of Ni–P alloy. All these results indicated that key issues are the optimal setup of process parameters to control the grinding zone temperature and the selection of a proper grinding wheel to avoid catalytic elements such as Ni and P.

Preparation and performance of resin-bonded grinding wheel with braze-coated diamond grits

The use of braze coating is proposed to obtain a layer of filler alloy on different types of diamond grits for improving diamond grit retention in resin-bonded diamond wheels. The effects of brazing on surface morphology and mechanical properties of diamond grits were evaluated. Resin-bonded diamond wheels with braze-coated diamond grits were prepared, and the grinding performances of cemented carbide wheels with different diamond grits were tested. Brazing could successfully cover most of the diamond grits with a layer of filler alloy. Pores and bumps of several microns in size were observed as well as the formation of titanium carbide (TiC) between the coating and diamond grit. Toughness indexes (TIs) of coated single-crystal diamond grits (RVD) decreased only slightly, but significantly increased for coated polycrystal diamond grits (PDGF1). The wheel containing coated PDGF1 diamond grits exhibited the lowest grinding forces and highest grinding ratio among the four wheels evaluated, whereas the wheel with coated RVD diamond grits produced the highest grinding force and a relatively low grinding ratio.

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.

Research on arc-shaped wheel wear and error compensation in arc envelope grinding

Arc envelope grinding method (AEGM) is commonly used for grinding large-aperture mirrors and greatly increases the wheel life and the machining accuracy. As the grinding point shifts on the arc-shaped wheel, a three-axis machine tool is qualified to manufacture aspherical or off-axis surfaces. However, compared with traditional aspherical grinding with a rotary table, grinding process on T3-configuration machine tools is more complicated. The grinding point varies in both latitude and longitude directions on the wheel. In this paper, a new algorithm for wear simulation based on 3D wheel-workpiece contact area is proposed to better understand the wear process in grinding aspherical surface. The resin-bonded diamond wheel was trued by GC (green silicon carbon) wheel. In order to get the grinding ratio, the wear of the wheel profile was measured after grinding a flat SiC-ceramic surface several times. Then, the wheel profile error was compensated first by analyzing the wheel-workpiece contact status. Gaussian process (GP) regression method was used to fit the form error and eliminate both noise and high-frequency waves in the measured data. The residual error was further compensated, and the compensation value was calculated by GP model. The proposed error compensation methods were verified on a three-axis grinder, and RMS value was successfully reduced by 37%.

Investigation of diamond wheel topography in Elliptical Ultrasonic Assisted Grinding (EUAG) of monocrystal sapphire using fractal analysis method

The wear behaviors of grinding wheel have significant influence on the work-surface topography. However, a comprehensive and quantitative method is lacking for evaluating the wear conditions of grinding wheel. In this paper, a fractal analysis method is used to investigate the wear behavior of resin-bonded diamond wheel in Elliptical Ultrasonic Assisted Grinding (EUAG) of monocrystal sapphire, and a series of experiments on EUAG and conventional grinding (CG) are performed. The results show that the fractal dimension of grinding wheel topography is highly correlated to the wear behavior, i.e., grain fracture, grain pullout, and wheel loading. An increase in cutting edge density on the wheel surface results in an increase of the fractal dimension, but an increase in the grain pullout and wheel loading results in a decrease in the fractal dimension. The wheel topography in EUAG has a higher fractal dimension than that in CG before 60 passes due to better self-sharpening behavior, and then has a smaller fractal dimension because of more serious wheel loadings after 60 passes. By angle-dependent distribution analysis of profile fractal dimensions, the wheel surface topography is transformed from isotropic to anisotropic. These indicated that the fractal analysis method could be further used in monitoring of a grinding wheel performance in EUAG.

Grinding performance improvement of silicon nitride ceramics by utilizing nanofluids

Abstract Silicon nitride ceramics are widely used as advanced structural components because of their excellent thermal and mechanical properties at ambient and elevated temperatures. In manufacturing industries, grinding is an efficient and productive technique for finishing ceramic workpieces. However, high wheel-workpiece friction and the extreme hardness associated with silicon nitride cause large heat generation during grinding. The heat produced during grinding impairs the workpiece quality by inducing surface and sub-surface damages, tensile residual stresses etc. The damages can critically limit the applications of ground ceramic components. Extensive experimental studies have been carried out to find the effect of dry and nano MQL (Graphite, WS 2 and MoS 2 ) grinding conditions on silicon nitride using resin bonded diamond wheel at different parametric (wheel speed, depth of cut and table speed) combinations. Results indicate that the use of nanofluids considerably improve the process performance in terms of grinding forces, surface finish and sub-surface damage. The ground surface is characterized by optical microscopy, SEM/EDX and XRD.

A novel approach of high-performance grinding using developed diamond wheels

A novel approach of high-performance grinding is proposed using developed diamond wheels, to obtain minimally damaged surface layer in silicon wafers. For this reason, resin bond diamond wheels are specifically developed with lanthanum oxide (La2O3), magnesium oxide (MgO), and ceria (CeO2) as additives, respectively. The wheels contain grains with a mesh number of 20,000 and a volume fraction of diamond grains of 37.5%. The diamond wheel with ceria additives demonstrates the best grinding performance in terms of surface integrity and roughness. It allows to generate an amorphous surface layer of 43 nm in thickness, without grinding damage beneath in a silicon wafer. This is different from previous reports, in which an amorphous layer is at the top, followed by a damaged crystalline layer underneath induced by a diamond wheel. Below the amorphous layer is the pristine crystalline lattice, which is confirmed using the high-resolution transmission electron microscopy (HRTEM). The ceria wheel results in a surface roughness R a of 0.88 nm and a peak-to-valley (PV) value of 8.3 nm over an area of 70 × 50 μm2 on a Si wafer at a feed rate of 15 μm/min.

Research on Grinding Force of Zirconia Internal Grinding with Resin Bond Diamond Wheel

The zirconia parts are limited by machined surface quality. The grinding force is one of the most important parameters of grinding and has effects on surface quality. The MK2710 grinder and resin bond diamond wheels were used in zirconia grinding. The grinding force was obtained by Kistler dynamometer. The paper focused on wheel speed and grain size on grinding force, and examined the surface by SEM. The research results indicated that decreasing the grain size, the grinding force increased and the surface quality improved, and increasing wheel speed could decrease grinding force to improve grinding surface quality. The results can improve zirconia ceramic parts surface quality and promote application.

Characteristics in Grinding of YVO&lt;sub&gt;4&lt;/sub&gt; with a Resin Bond Diamond Wheel

An investigation was undertaken to explore the grinding characteristics in grinding of yttrium vanadata (YVO4) crystal by using a resin diamond wheel. The grinding forces and surface roughness were measured and the morphological features of ground workpiece surfaces were examined. The results indicate that the depth of cut is the leading factor in affecting grinding forces whereas the surface roughness is mainly governed by the grinding speed. The material removal mechanism was found to be dominated by brittle fracture mode at conventional grinding speeds, and gradually transfer to ductile flow mode under higher grinding speeds, which is greatly related to the maximum undeformed chip thickness.

Study on the abrasion mechanism of ultraviolet cured resin bond diamond wheel

Based on an extensive review of traditional machining technologies, a novel method to manufacture abrasive tools using ultraviolet (UV) light curing technique was proposed to achieve the economy and accuracy for machining ceramic materials. The UV cured resin bond tools have been proven to have substantial advantages in machining performance. However, there has been limited research on the abrasion mechanism of such tools. In this paper, the mechanism of such resin bond tools is proposed as a hybrid of conventional grinding and lapping, and called as a grinding/lapping (G/L) process. In order to verify the proposed mechanism, three resin bond diamond wheels cured by UV light were used to conduct lapping, grinding, and G/L process, respectively, under the same experimental set-up. The experimental results like surface roughness (RA) and surface profiles of the workpieces undertaking the three operations were compared and showed good agreement with the proposed mechanism.

Study on the abrasion mechanism of ultraviolet cured resin bond diamond wheel

Based on an extensive review of traditional machining technologies, a novel method to manufacture abrasive tools using ultraviolet (UV) light curing technique was proposed to achieve the economy and accuracy for machining ceramic materials. The UV cured resin bond tools have been proven to have substantial advantages in machining performance. However, there has been limited research on the abrasion mechanism of such tools. In this paper, the mechanism of such resin bond tools is proposed as a hybrid of conventional grinding and lapping, and called as a grinding/lapping (G/L) process. In order to verify the proposed mechanism, three resin bond diamond wheels cured by UV light were used to conduct lapping, grinding, and G/L process, respectively, under the same experimental set-up. The experimental results like surface roughness (RA) and surface profiles of the workpieces undertaking the three operations were compared and showed good agreement with the proposed mechanism.

Characteristics in Grinding of YVO&lt;sub&gt;4&lt;/sub&gt; with a Resin Bond Diamond Wheel

Characteristics in Grinding of YVO&lt;sub&gt;4&lt;/sub&gt; with a Resin Bond Diamond Wheel