Diamond Grits Research Articles

Machining Performance for Ultrasonic-Assisted Magnetic Abrasive Finishing of a Titanium Alloy: A Comparison with Magnetic Abrasive Finishing

Titanium alloys are widely used in aerospace, the military industry, electronics, automotive fields, etc., due to their excellent properties such as low density, high strength, high-temperature resistance, and corrosion resistance. Many components need to be finished precisely after being cut in these applications. In order to achieve high-quality and high-efficiency finishing of titanium alloys, ultrasonic-assisted magnetic abrasive finishing (UAMAF) was introduced in this research. The machining performance for UAMAF of a titanium alloy was studied by experimentally comparing UAMAF and magnetic abrasive finishing (MAF). The results show that the cutting force of UAMAF can reach 2 to 4 times that of MAF, and it decreases rapidly with the increase in the machining gap due to the energy loss of ultrasonic impact in the transmission between magnetic abrasives. The surface roughness of UAMAF can reach about Ra 0.075 μm, which is reduced by about 59% compared with MAF. The main wear type of the magnetic abrasive is that the diamond grits fell off the magnetic abrasive in both UAMAF and MAF. The uniform wear of the magnetic abrasive is realized, and the utilization ratio of the magnetic abrasive is obviously improved in UAMAF.

Study on surface integrity and ductile cutting of PV polycrystalline silicon and wear mechanisms of electroplated diamond wire

This study aimed to evaluate and better understand the mechanical and crystalline responses of polycrystalline silicon sawn by diamond wire sawing. To simplify the multi-wire sawing kinematic, an endless wire saw with a single looped diamond wire welded was used. The wire cutting speed and feed rate were varied in order to evaluate the characteristics of surface morphology, surface roughness, and subsurface damage. The analysis of brittle-ductile transition and residual stress of the sawn surface and silicon chips were performed with Raman spectroscopy. The wear and failure mechanism of the diamond wire were analyzed. The results showed that sawn surface is composed of brittle and ductile regions and the predominance of one of these directly affected the surface roughness Ra. The ductile cutting mode induced the predominance of microgrooves and ploughing over the sawn surface and led to formation of an amorphous layer with residual compressive stress around of − 192.3 MPa. Micro-cracks in subsurface were identified and it reached a minimum depth of 7.2 ± 1.6 µm. Chip fragments and elongated chips were observed and latter is practically amorphous. The wire wear analysis indicated that during the cutting there is deformation of the Ni-layer, exposed grits, and grit pullout. The main wear mechanisms are Ni-matrix removal and abrasive wear of the diamond grit. A better surface quality of polycrystalline silicon was obtained on increasing wire cutting speed and decreasing feed rate. Thus, the looped diamond wire sawing allows to reach a high surface quality of the silicon wafer, since the material removal occurs more in ductile cutting mode, generating a smooth surface with shallow subsurface damage.Graphical abstract

Influence of CrB2 additive on the morphology, structure, microhardness and fracture resistance of diamond composites based on WC‒Co matrix

In the paper, structure and properties of novel diamond composite with enhanced properties were presented and discussed. The samples were prepared using the method of cold pressing followed by the originally developed two-stage vacuum hot pressing under electric current activation. It was demonstrated that addition of different amounts of chromium diboride to the WC–6 wt.%Co composite had significant effect on its microstructure, phase composition and, hence, mechanical characteristics. It was found that percentage 4 wt.% of CrB2 provided the most advantageous characteristics. In the second stage of researches, this composition was used as a matrix for the diamond reinforcement. The obtained results of analysis suggested that enhancement of the composite could be attributed to the dispersed strengthening mechanism and structure modification. In particular, important role played reduction of the average grain size of the carbide phase from 5.6 to 3.4 μm, disappearance of pores at the Co binding phase, formation of inhibitor phase clusters at the interphase boundaries, and the specific pattern of phases present in the composite. Chromium diboride contributed also to the formation of dense and strong interface between diamond grits and refractory matrix. Advantageous distribution of residual stresses around the diamond grits appeared in the sintered samples with CrB2, providing additional fixation of the diamond reinforcement in the matrix. It was also demonstrated that further increase of CrB2 content above 4 wt.% in the WC–6 wt.%Co composite material lead to a deterioration in its mechanical properties, which could be attributed to further, disadvantageous changes in the structure, especially in grain size and phase composition.

Ductile-brittle transition mechanisms in micro-grinding of silicon nitride

Ductile grinding of brittle materials is essential for high precision applications and to maintain the strength and lifetime of the parts. The critical chip thickness of a brittle material defines a threshold for the lateral cracks' initiation in the workpiece due to the grains’ penetration. For ductile grinding, keeping the uncut chip thickness below the critical chip thickness of the brittle material is necessary. This study focuses on the ductile micro-grinding of Si3N4 as an advanced ceramic and brittle material. The critical chip thickness and the maximum uncut chip thickness were first calculated based on the material properties, the grinding parameters and the microtopography of the utilized grinding pin and then validated by both diamond grit scratches and micro-grinding experiments. Micro-grinding experiments on an inclined workpiece were conducted to investigate the material removal regimes of Si3N4. Grinding forces and surface integrity (surface roughness, surface topography and subsurface damages) induced by different micro grinding parameters and micro-grinding of an inclined workpiece are analyzed in detail. The estimated critical chip thickness and measured maximum uncut chip thickness could be used as an exact guide for achieving the ductile micro-grinding mode. The experiments revealed that the material removal mechanism mainly affects the micro-ground surface integrity. The ductile material removal mode induced no detectable subsurface damage and the surface quality deteriorated by the brittle removal mode.

Microstructure, mechanical properties and reciprocating wear properties of diamond grits-reinforced NiCrBSi composite coatings on 42CrMo

In this study, diamond grits-reinforced wear-resistant NiCrBSi composite coatings with diamond exposed to the air (Sample I) and embedded in the coating (Sample II) were prepared on 42CrMo steel by vacuum cladding technique. Moreover, a post-heat treatment was performed to restore the weakened substrate. The surface morphology, interfacial microstructure, mechanical properties and reciprocating wear properties of the coated samples, as well as the post-heat-treated samples, were investigated. Besides, the wear mechanism was discussed. On both the coatings, flaky and prismatic structure and rectangular precipitates around diamond grits were chromium carbides. The cross-sectional morphology and EDS results showed that a metallurgical bonding interface was developed by the apparent element diffusion between the cladding layers and the 42CrMo steel substrates, which was beneficial for ensuring their bonding strength. Both the NiCrBSi/diamond composite coatings could significantly improve the wear resistance of 42CrMo steels. The wear resistance of Sample I and Sample II were 7.7 times and 5.3 times heavier than that of the original substrate, respectively. The abrasive, adhesive, and oxidative wear occurred during the friction-wear tests, in which the abrasive wear was dominant. In addition, the dominant wear mechanism of 42CrMo steel was adhesive wear. After the post-heat treatment, the weakened properties of 42CrMo steel were restored due to the phase transformation from lath martensite and ferrite to lamellar pearlite and ferrite. Further, the treated 42CrMo steel achieved higher properties than the original substrate and retained the excellent wear properties of the surface composite coating.

Microstructure and performance of glass fiber metal composite-bonded diamond segment with Cu-Sn-Ti alloy

To develop metal-bonded diamond tools without dressing during machining, a novel glass fiber metal composite bonding agent with Cu–Sn–Ti alloy was proposed. The three-point bending strength of the diamond segments and the Vickers microhardness of the solidified composite bonding agents were tested. The microstructures of the diamond segments were investigated and the wear tests were performed for each group of diamond segments. The results showed that diamond segments with glass fiber content of 1.55 wt % - 6.89 wt % exhibited lower bending strength (declined by 36.4%–80.4%) and smaller microhardness (reduced by 16.0%–87.9%), compared to those of the diamond segment with no glass fiber addition. Good bonds were formed among the Cu–Sn–Ti alloy, glass fibers, and diamond grits. Chemical reactions occurred between the Cu–Sn–Ti alloy and glass fibers during high-temperature brazing, forming new intermetallic compounds such as Ti5Si3, Ti2O3, and Ti(Cu, Al)2, which improved the bonding strength. With an increase in the glass fiber content, fractures were more likely to occur in the glass fibers than in the diamonds, resulting in the bending strength decreasing more and more slowly. The wear resistance of the diamond segments decreased gradually with increasing glass fibers weight content. The diamond segment with 4.98 wt % glass fibers exhibited the best and most stable wear performance.

Comparison of loupes versus microscope-enhanced CAD-CAM crown preparations: A microcomputed tomography analysis of marginal gaps

Statement of problemLong-term restoration success depends on a precision marginal fit to prevent marginal leakage and caries. The successful fit of a computer-aided design and computer-aided manufactured (CAD-CAM) crown may be affected by different workflow variables, including preparation, scanning, crown design, milling, sintering, and cementation. Discrepancies in any of these steps may result in poor marginal and internal fit. Evidence suggests that tooth preparation may be the most important step in the workflow for a successful outcome. Compared with the traditional means of crown preparation using the naked eye or loupes, the dental operating microscope provides higher magnification and more direct illumination. However, the impact of high magnification during preparation on the marginal quality of CAD-CAM crowns is unclear. PurposeThe purpose of this in vitro study was to compare marginal fits of CAD-CAM crowns fabricated after initial preparation with loupes and subsequent preparation refinement with either loupes or a microscope. The null hypothesis was that no significant difference would be found in the marginal gap between the preparations with loupes and those with a microscope. Material and methodsMounted extracted molars (N=18) received initial crown preparations with a coarse grit, rounded shoulder, diamond rotary instrument with loupes of ×3.0 magnification. The teeth were then randomly divided into 2 groups and refined for an additional 2 minutes with fine grit, rounded shoulder, diamond rotary instruments with either loupes (LOUP) or a microscope up to ×10.0 magnification (DOM). The prepared teeth were scanned with an intraoral scanner to fabricate zirconia-reinforced lithium silicate crowns manufactured with a 4-axis milling machine, sintered in a dental furnace in accordance with the manufacturer’s instructions, and cemented with self-adhesive resin cement. All teeth with crowns were mounted and scanned with a microcomputed tomography (μCT) system at 21-μm nominal voxel size. The resulting Digital Imaging and Communications in Medicine (DICOM) images were imported into a semiautomatic segmentation software program. Marginal and absolute gaps were measured at 24 consistent circumferential points per specimen. Absolute gaps were labeled, and the total volume was calculated. Paired and unpaired t tests were used for statistical analysis (α=.05). ResultsThe mean marginal gap was 145.0 ±259.6 μm for LOUP and 35.6 ±110.6 μm for DOM, with a statistically significant difference (P<.001). The mean gap volume for LOUP was 0.975 ±0.811 mm3, and 0.250 ±0.477 mm3 for DOM, also statistically significantly different (P=.023). A significant difference was found between the absolute and marginal gaps for LOUP (P=.007), but for DOM, the difference was not significant (P=.063). ConclusionsThis study demonstrated that the higher magnification used during tooth preparation played a significant role in the size of marginal gaps present around CAD-CAM crowns. Crown preparations finished by using fine grit diamond rotary instruments with a microscope at higher magnification than loupes resulted in a more precise marginal fit with smaller gaps.

Towards tailorable interface microstructure through Solid-state interface reaction between synthetic diamond grits and sputtered Ni-Cr binary alloy

In this work, the solid-state (S/S) interface reaction between single-crystal synthetic diamond grits and binary Ni-Cr alloys has been comprehensively studied on (100) and (111) crystal planes using Raman spectroscopy, SEM, TEM, and XPS techniques, in combination with first-principles calculation. The early-stage interfacial chromium carbides formation was found to be dependent on crystal orientation of synthetic diamond, which can be explained by geometric optimization that explores the underlying catalytic mechanisms of Ni-Cr alloys on the relaxation and bonds construction of C atoms on (100) and (111) crystal planes of diamond. More importantly, a unique interfacial microstructure, namely a Ni-rich layer instead of interfacial carbides was formed directly on diamond surface of S/S reaction samples at 700 and 900 °C. In addition, the phase transformation between Ni-rich phase and chromium carbides formed in the S/S interface reaction between Ni-Cr alloy and synthetic diamond were comparatively examined at 700 and 900 °C and investigated through a careful TEM lattice mismatches analysis. Ultimately, a mechanism to tailor the S/S interface microstructure by simply designing alloy compositions and reaction temperatures was proposed with experimental validation.

Cu-induced enhancement of interfacial bonding for brazed diamond grits with Ni[sbnd]Cr filler alloys

Restraining diamond graphitization is still the potential problem for brazed diamond tools with NiCr filler alloys. Herein, we systematically investigate the interfacial bonding and mechanical performance of brazed diamond tools with Cu-doping NiCr filler alloys through multi-scale atomistic simulations and experiments. First-principles calculations show that the Cu-doping not only inhibits the structural damage of diamond, but also enhances the metallurgical bonding between diamond and filler alloys. The tensile simulations of Ni-Cr-Cu/diamond interface further verify the strengthening effects of Cu-doping since these bonds of CC within diamond and Ni-Cr-C at interface can withstand greater tensile strains. Combined with molecular dynamics simulations, Cu-doping effectively weaken the graphitization of diamond, which is confirmed through experimental Raman spectroscopy detection. More importantly, the brazed diamond tools by NiCr filler doped with 40 wt% Cu alloy exhibit excellent mechanical grinding performance. These results shed a new light on improving the mechanical properties of brazed diamond tools.

Interfacial microstructures and Grinding performance of Synthetic Diamond Grits brazed by Cu-22Sn-3Cr Alloy

To ensure the reliable bonding and low thermal damage of brazed diamond grits, a Ni-free Cu-Sn-Cr filler alloy was developed based on our previous study. Interfacial microstructure of diamond grits brazing used by Cu-22Sn-3Cr (in wt. %) filler alloy at 950 °C for 5, 10, 20, and 40 min were systematically investigated. Only Cr7C3 was generated at the interface between diamond and Cu-22Sn-3Cr alloy, and the thickness of Cr7C3 was increased after extended brazing time. The grinding performance of diamond tools brazed using Cu-22Sn-3Cr alloy has fewer ratios of diamond grits with breakage and fall-off failures and thus was found to be superior to that brazed by Ni-14Cr-10P filler alloy. In addition, alloy composition has a more significant influence than brazing time on the interfacial microstructure and mechanical behavior of brazed diamond grits; and the higher mechanical behavior of diamond grits brazed using Cu-Sn-Cr filler alloy is proved to be closely related to the low solubility of C in Cu-Sn-based alloy. Results obtained in this work are also crucial for developing a diamond brazing technique to fabricate diamond-related materials and devices.

Fractal and multifractal analysis on fused silica glass formed by bound abrasive grain mediated grinding using diamond grits

Optical component fabrication involves highly controlled polishing and lapping methods. The method used for polishing and lapping depends upon the application and the properties required. The main properties of materials for the optical purpose are roughness (Ra) and Subsurface damage (SSD). The control of these parameters has to be done right from the early stages of lapping. This work is based on the fractal and multifractal based study on the surface roughness of fused silica glass samples lapped with a deterministic grinding method using abrasives, diamond particles embedded in different matrixes such as metal bound and resin-bound of different grit sizes. White light interferometry is carried out to study the average roughness of the samples. A field emission scanning electron microscope (FESEM) was used to take the images of the samples. Fractal and multifractal analyses are done to find the relation between the fractal parameters and the average roughness of the sample formed for different grit sizes of the matrix as well as different abrasives used.

Evaluation of the Efficacy of Two Fibre-Reinforced Post Removal Techniques.

The aim of this in-vitro study was to compare the amount of material (post and luting agent) and root dentine removed using two methods for removal of endodontic posts. Human premolar teeth (n=20) were sectioned at the CEJ and fibre reinforced posts were cemented at a length of 10mm following root canal therapy. Teeth were randomly assigned to two study groups. The methods of removal compared were: the use of RTD re-access kit (Composipost, RTD, France, St Egreve) in a conventional hand-piece driven by an electric motor (Group A); or a long tapered diamond bur (FG Diamond grit bur, Dentsply Ltd, UK) in an air-driven high speed turbine (Group B). Using micro- CT the volume of material and root dentine removed for each sample was calculated. Both the volume of material removed and the volume of root dentine removed were significantly greater when using diamond burs. (p⟨0.001). The volume of dentine removed using the diamond bur method (mean 22.64mm³) was greater than the volume removed using the reaccess kit (mean 11.71mm³). Use of a diamond bur to remove fibre reinforced endodontic post removal poses higher risk for root perforation compared to the reaccess kit.

Wear behavior and morphologic characterization of diamond segments induced by crystal plane characteristics of diamond grits in sawing hard materials

The wear of diamond grains (DGs) is a classic problem, affects the final cost, in sawing hard materials (granitic rocks) for slabs. However, the previous research rarely pays attention to study the wear of DGs considering the crystal plane characteristics. Hence, in this study, the aim is to explain the fracture morphology of DGs in sawing granitic rocks taking into account the crystal plane characteristics. The wear experiment was carried out with a frame saw. Then the surface morphology of DGs was characterized by scanning electron microscope (SEM). According to wear characteristics of DGs, the wear of DGs was divided into seven different types, including fresh, whole, micro fractured, pulled-out, flush with matrix, macro fractured and blunt. Interestingly, the bottom surface of the pulled-out DGs in contact with the matrix was mostly {100} crystal planes that account for approximately 80%. In addition, flush with matrix mostly occurred on the {111} crystal planes (account for 90%), and mostly at both ends of the diamond segments (DSs). Then, this phenomenon is explained by the interplanar spacing of DGs. Moreover, wear behavior and morphologic characterization of DGs were discussed considering the factors of stone sawing (e.g., detritus) and the characteristics of DGs (e.g., dislocation). Finally, wear evolution mechanism of DSs topography were proposed. This research enhances to deeply understand the wear of DGs in granite processing and provides guidance for the design of DSs.

A novel drill bit design for reducing bone-chip morphology in orthopaedic bone drilling

Bone drilling is necessary during orthopaedic surgery for internal fixation. The drilling through the bones is the same as the mechanical drilling that uses a surgical twisted drill bit. The design and geometry of drill-bit play a paramount role in producing bone debris of various shapes and sizes. These different bone chips are responsible for chip clogging and chip accumulation at drill sites, leading to a higher temperature, torque, and thrust force. This study compared three hollow drill bits with different diamond grit sizes with a conventional surgical twisted drill bit to observe the chip morphology. It was witnessed that the influence of diamond grit size plays a significant role in producing bone debris. Different sizes of bone chips were stimulated with various drill bits. Similar chip characteristics were observed in all types of bone debris with varying drill bits. The twisted drill bit produces thick spiral-shaped bone debris compared to the hollow drill bit. The fine diamond grits in the drill bit reduce the chip morphology of bone debris during bone drilling. Thus, the diamond-impregnated surgical tool is preferable to drilling burr than a surgical twisted drill bit for surgeons during orthopaedic surgery.

Microstructures and Mechanical Properties of Brazed Diamond Grits with Cesi2-Doped Ni-Cr Filler Alloy

Microstructures and Mechanical Properties of Brazed Diamond Grits with Cesi2-Doped Ni-Cr Filler Alloy

Optimization of the continuity of the aspherical production processes in asphericon s.r.o based on subsurface damage and microroughness analysis

In the paper is presented an analysis and optimization of the standardized sub-apertural grinding process used in the serial production in asphericon s.r.o. The monitored parameter was the depth of subsurface damage and surface microroughness. Tested were five grinding processes, which were automatically generated by the internal system, for five different diamond grit sizes (D151, D91, D64, D30, and D15). For evaluation of the depth of the defected layer was used modified wedge polishing method which is suitable for analysis of the rotationally symmetrical sub-apertural grinding processes [1]. For identifying the presence of the subsurface damage two methods were used. Defect detection using an optical microscope, as the broadly used and reliable method, and detection by standard ISO control to get the comparison with the method used in common serial production. The microroughness was measured using a white-light microscope concerning the used grinding tool and the amount of removed material. Within the experiment was found as the most effective two-step process uses D91 for rough grinding and D30 for fine grinding. D91 provides a very good removal characteristic with final subsurface damage of 44 µm which is possible to grind out using the D30 tool in two steps with final subsurface damage 22 µm in a total processing time of 137 minutes. This grinding process is timewise in best balance with 80 minutes long polishing process and therefore minimize the production cost. Result microroughness around 2 nm Sq in the fully polished zone is already limited by the polishing process. Using a finer grinding tool is not bringing improvement in the surface microroughness just shortening polishing time due to lower subsurface damage.

Experimental investigation of rotary ultrasonic face milling on red granite: A comparison with conventional grinding

Long-term sustainability with cost-effective machining and materials are used in many companies these days. Also, precise machining on brittle and hard materials is becoming a challenge for production engineering. Rotary ultrasonic face milling (RUFM) is an unconventional milling process that is preferred to perform precise surface machining on such materials. The research work aims to analyse the enhancement in conventional diamond grinding (CG) due to the addition of ultrasonic vibration and compare both processes (RUFM and CG). Analysis of variance (ANOVA) technology was applied for the analysis. The scanning electron microscopy (SEM) technique was used to analyse the tool wear after milling operation. The controlling factors used for the study were feed rate, depth of cut, and ultrasonic power. The outcomes of the study showed an increment in material removal rate during RUFM compared to CG. Material removal rate (MRR) also increases with increment in each level of controlling factors. Surface roughness (SR) increases with the addition of ultrasonic vibration during RUFM. Also, SEM technology shows the complete removal of diamond grits at the bottom surface of the tool. The research concluded that tool life and material removal rate get improved but the reduction in surface finish during RUFM while comparing to CG.

Microgrinding of lithium metasilicate/disilicate glass-ceramics

Lithium metasilicate and disilicate glass-ceramics (LMGC and LDGC) are attractive dental materials but poor surface quality produced in current milling/grinding is a technical bottleneck. This paper reports on the microgrinding characteristics and mechanisms of LMGC and LDGC using micro-pencil diamond tools at different conditions. Surface quality was assessed using 3D laser confocal microscopy in terms of comprehensive roughness parameters. A combination of brittle and localized ductile removal mixture and brittle fracture was featured on the microground LMCG and LDGC surfaces identified through microscopic examination. The generation of brittle and localized ductile areas significantly depended on the diamond grit size and the depth of cut, resulting in different surface asperities. Better surface quality was achieved with reduced diamond grit size and depth of cut. The nanoscale maximum grit cutting depth in microginding achieved the best average and maximum roughness values of 0.241 ± 0.009 μm and 4.380 ± 0.861 μm for LMGC with approximately 80% and 60% reductions in comparison with dental CAD/CAM milling, respectively. Microgrinding of LDGC also achieved the best average and maximum roughness values of 0.168 ± 0.013 μm and 3.693 ± 0.467 μm with more than 90% improvement compared with simulated conventional grinding, simplifying the manufacturing procedure for LDGC restorations. Microgrinding also produced the kurtosis and skewness for both materials comparable to human teeth. More diamond tool wear occurred in microgrinding of high-strength LDGC than low-strength LMGC. Although microgrinding of multiphase LMCG and LDGC in ductile regime can be challenging due to microstructural diversity, the technique can advance current CAD/CAM milling/grinding for high-quality shaping of high-strength ceramic restorations.

The making and performance of patterned-monolayer brazed diamond wheel produced with Ag-based novel active filler

Present paper delineates a novel route adopted for successfully manufacturing single layer brazed patterned diamond wheels with enhanced attributes. A pneumatic pick-drop methodology is used for placing the grits in a uniform and patterned manner. Instead of commonly used Ni-Cr alloys, a novel formulation of μ-TiC inoculated composite Ag-Cu-Ti filler has been preferred, which helped in arresting crack formation at the root of grit brazement and simultaneously ensured high bond wear characteristics. Addition of μ-TiC particles substantially improved wear characteristics of basic Ag-Cu-Ti alloy but tend to impair its wetting ability on diamond surface with increase in its wt% in the composition. Therefore, its presence in the filler was restricted to only 2 wt% to keep such compromise within acceptable level. Wheels developed using active Ag-Cu fillers were further subjected to performance evaluation by grinding of WC-Co cermets. The operating parameters were changed in such a way that wheels experienced increasing order of grinding-aggressiveness. The degree of aggressiveness in the grit-work interaction has been defined by a unifying scalar quantity, termed as “aggressiveness number”. No trace of wheel loading was observed even in the most aggressive condition due to uniformly spaced grits. The failure counts of diamond grits are also related to this scalar. A detailed analysis is presented to address the suitability of μ-TiC reinforcement in the formulation of active Ag-Cu filler in the light of the grinding force and grit retention ability of the wheels.

Investigation on diamond damaged process during a single-scratch of single crystal silicon carbide

Through a series of single-scratch experiments, the damaged process of diamond grit and the material removal mechanism of single crystal silicon carbide (SiC) were investigated. The <111> and <110> planes of single diamond grits were used to scratch the carbon (C) face and silicon (Si) face of single crystal SiC, respectively. The damaged process and corresponding typical damaged morphology of diamond grits on different planes were analyzed. The material removal mechanism of single crystal SiC (C face and Si face) is analyzed. The results show that the contact width and the breaking angle were determined as the key damaged parameters of diamond grit by the analysis of the damaged process. However, the key factor to reduce surface damage is the state of the micro-edges that appear on the crystal plane of the diamond grit in contact with the workpiece during the scratching process.