Diamond Tool Wear Research Articles

Surface finishing and tool wear in single point diamond turning of chemical vapour deposited tungsten carbide hard coatings

Precision-engineered components which operate in demanding conditions often require the application of hard coatings such as tungsten carbide (WC) to improve their functional properties. Following the coating deposition process, a surface finishing or machining operation is often required to correct the sizing or achieve adherence to geometrical tolerancing and surface finish requirements. Single point diamond turning (SPDT) is a widely used ultraprecision machining technique for the fabrication of high-end engineering components made up of ductile materials, making it a desirable technique as a post-coating machining or finishing process. In this study the machinability of hard CVD W/WC coatings with a hardness of 1120 ± 15 HV and a thickness of 100 μm using SPDT was investigated. Here we report the results of axial and transverse turning using a cutting speed of 600 rpm and feed rates of 1 and 5 μm respectively. Experimental results show that an Ra of 0.2 μm is achieved with a diamond tool having a 0.5 mm nose radius. Significant tool wear was observed at the rake/flank edge of the diamond tool due to the coating's hardness. Surface and cross-sectional analysis of the samples' machined areas revealed presence of adhesive and abrasive wear. The occurrence of material pile-up due to tool loading on the surface of the coating was investigated through the indentation technique which demonstrated the occurrence of material deformation contributing to the overall surface roughness.

Wear of micro diamond tool in ultra-precision turning under dry and minimum quantity lubrication conditions

Minimum quantity lubrication (MQL) is an effective way to reduce the cutting temperature and tool wear. To reveal the effect of MQL on the wear of micro diamond tool, a calculation model for the cutting temperature of micro diamond tool under dry friction condition is established firstly by using the Fourier’s law of heat conduction. Regarding the boundary film as a layer of heat-conduction medium, a revised calculation model for the temperature distribution on tool rake face under MQL condition with different cutting fluids is further established. The predicted results indicate that low viscosity is beneficial to the wetting of cutting fluid on tool-chip contact interface, which can relieve the friction. The reduction of friction finally decreases the cutting temperature. Secondly, the cutting temperature–dependent wear volume of micro diamond tool is predicted by using the Usui wear rate model in response to different cutting fluids and different cutting distances. In dry cutting, the graphite wear of micro diamond tool prevails. However, the application of MQL can slow down the graphitization of diamond, so the wear of micro diamond tool visibly decreases. Finally, cutting experiments with different cutting fluids are performed to verify the established models. The experimental observations agree well with the theoretical prediction results. Such satisfactory consistency confirms that the cutting fluid with low viscosity can reduce the cutting temperature and inhibit tool wear effectively.

Insight into the graphitization mechanism of the interface between iron and diamond: A DFT study

It is an important topic in the manufacturing research field to understand the mechanisms for the wear of diamond surfaces. The density functional theory (DFT) methods have served as useful tools for studying chemical reaction mechanisms in processing. In this work, we studied the changes in the diamond structure during the interface contact between the iron and diamond. The iron-diamond contact area is simplified to different coverage rates of Fe atom, corresponding to different numbers of adatom. With the different numbers of the Fe adatoms, the interlayer CC bonds have different changes. Below the Fe adatom region, the interlayer CC bonds are strengthened, inhibiting the graphitization. It is noteworthy that the CC bonds became significantly weakened or even broken at the boundary of the interface contact. Moreover, the interface sliding simulation verifies that the graphitization preferentially occurs at the edge of the interface between iron and diamond. The actual cause of graphitization is the synergistic effect of the charge transfer of the FeC bonds and the asymmetric contraction and stretching on the diamond surface. Our work provides a theoretical basis for suppressing excessive diamond tool wear and polishing the diamond surfaces.

Crystal orientation and material type related suppression to the graphitization wear of micro diamond tool

According to the Hencky stress theorem and J-C constitutive equation, a cutting force model is established for the diamond turning process when using micro diamond tool, through which the stress distributions on tool rake face and flank face are calculated. A stress model is further developed to calculate the stress distribution on the cutting edge region by using the stress intensity factor theory of fracture mechanics, into which the influences of crystal orientation of rake and flank faces are integrated. With consideration of elastic modulus and defect density of diamond crystal, the critical stress for graphitization of diamond tool is also deduced in response to different crystal orientations and types of diamond material. Finally, cutting experiments are performed to validate the theoretical predictions. Results show that the experimental observations agree well with the theoretical predictions. Such satisfactory consistency confirms that the natural cape Ia diamond as tool material and the (100) crystal plane as tool faces can effectively inhibit the graphitization wear of micro diamond tool.

Ultraviolet-ozone assisted ultrasonic vibration cutting for extending diamond tool life

Ultrasonic vibration cutting (UVC) has proven its effectiveness in suppressing the severe chemical wear of diamond tools in machining of metals with strong chemical affinity to carbon, and the formation of inert oxide film on the freshly cut metal surface is expected to further extend the tool life due to the oxide’s passivation effect. Based on the existing tool wear suppression mechanism to slow the diamond graphitization, this paper proposed ultraviolet-ozone assisted UVC to further enhance the oxide formation and improve the diamond tool life. A numerical model for calculating the oxide formation rate is developed to study the influence of supplying gases with different oxidizing capabilities. Meanwhile, an in-situ ultraviolet-ozone assisted UVC system is in-house built, and the diamond tool wear for cutting of stainless steel and tungsten are studied. Experimental results show that, compared to air, oxygen and ozone, ultraviolet-ozone assisted UVC demonstrates the highest oxide growth rate and the longest tool life accordingly, which further verifies the theory that metal oxidation performs an important role in suppressing the chemical wear of diamond tools.

Analysis of diamond tool wear mechanism in terms of stress for KDP Fly cutting

Although KDP (Potassium dihydrogen phosphate) crystal is very soft and brittle compared with diamond, the wear of diamond tool still exists in flying cutting, though the wear is much slower than that of diamond cutting copper and aluminum. The high technical requirements of KDP flying cutting has a small tolerance to tool wear. And the tool wear causes the quality of KDP processing uncontrollable, which results in low efficiency of processing and even workpiece scrap. In this paper, through the stress analysis of KDP lattice damage based on the first principle theory and the mechanical analysis of the cutting edge of diamond tool, it is proposed that the stress induces the wear of diamond tool in KDP flying cutting. The understanding of the wear mechanism of diamond tools lays a foundation for further research on the wear law of tools and for exploring the methods of prolonging the service life of tools.

Suppression of diamond tool wear with sub-millisecond oxidation in ultrasonic vibration cutting of steel

• Compressed air suppresses diamond wear in ultra-sonic cutting of stainless steel. • Thicker Fe oxide layer on steel surface helps further suppression of tool wear. • High air pressure increases O 2 partial pressure at interface and oxide thickness. • Sufficient oxide layer on fresh-cut steel forms within ultra-sonic cutting interval. • Proposed hypothesis of oxidation replenishes the existing wear suppression theories. Ultrasonic vibration has been applied to suppress the chemical tool wear in ultra-precision diamond cutting of steel and other alloys. The tool wear is found significantly reduced with enriched ambient oxygen concentration. In this study, instead of supplying costly and potentially hazardous high concentration oxygen to the machining zone, a greener alternative, high-pressure air coolant has been applied to enhance the oxygen content at the cutting area. The effect of air-blowing pressure on ultrasonic vibration cutting of stainless steel was investigated, using both polycrystalline and single-crystal diamond tools. It has been found that an increased air blowing pressure and a more closely positioned nozzle not only improve the cutting performance but also reduce tool wear, reflecting consequences from both chemical and fluidic dynamics aspects. A higher air blowing pressure will increase the instantaneous air pressure as well as the density of oxygen molecules around the cutting zone. This increases the passivation speed for the freshly cut steel surface caused by the formation of thin oxide layers. Experimental results have formalized the findings that sub-millisecond oxide formation is the key factor to suppress diamond tool wear.

Theoretical Insight Into Diamond Doping and Its Possible Effect on Diamond Tool Wear During Cutting of Steel

Natural diamond tools experience wear during cutting of steel. As reported in our previous work, Ga doping of diamond has an effect on suppressing graphitization of diamond which is a major route of wear. We investigate interstitial and substitutional dopants of different valence and different ionic radii (Ga, B, and He) to achieve a deeper understanding of inhibiting graphitization. In this study, ab initio calculations are used to explore the effects of three dopants that might affect the diamond wear. We consider mechanical effects via possible solution strengthening and electronic effects via dopant-induced modifications of the electronic structure. We find that the bulk modulus difference between pristine and doped diamond is clearly related to strain energies. Furthermore, boron doping makes the resulting graphite with stable sp2 hybridization more perfect than diamond, but Ga-doped diamond needs 2.49 eV to form the two graphene-like layers than only one layer, which would result in the suppressed graphitization and reduced chemical wear of the diamond tool.

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.

Diamond tool wear monitoring by sensory analysis in milling of absolute black granite

Diamond tools suitable for machining operations of natural stones can be divided into two groups: cutting tools, including blades, the circular blades and the wires, and the surface machining ones, involving mills and grinders, that can be of different shapes. For the stone sawing process, the most adopted tool type is the diamond mill, whose duration and performance are influenced by various elements such as: the mineralogical characteristics of the material to be machined; the working conditions such as the depth of cut, the feed rate and the spindle speed; the production process of the diamond segment and the characteristics of both the matrix and the diamond, such as the size, the type and the concentration of the diamonds and the metal bond formulation hardness. This work allows to indirectly assess the wear of sintered diamond tools by signal analysis (in time and frequency domain) of the cutting force components acquired in the process. The results obtained represent a fundamental step for the development of a sensory supervision system capable of assessing the tool wear and hence to modify the process parameters in process, in order to optimize cutting performance and tool life.

Experimental Analysis of Abrasive Diamond Tool Wear and their Cutting Force in Stone Machining Process

Stone machining with a diamond tool is a common procedure for producing both standard items and design shapes, such as tiles, slabs and so on. During the entire deep sawing process of a granite work piece with finite length cutting procedure in stone processing, force components acted on the saw-blade. The work is split into two parts: theoretical and practical. The theoretical section discusses the features of diamond blades, cutting process methodology, and stone mining and processing methods. The practical portion of the project focuses on the wear of diamond blades when cutting stone, notably granite. The overall weight of the cutting blade and the loss of tooth height as a function of time are used to determine blade wear for two cutting blades from different manufacturers. There is a linear relationship between the two measured values. The findings serve as the foundation for a cost-benefit analysis of both diamond wheels.

A review of tool wear mechanism and suppression method in diamond turning of ferrous materials

In ultra-precision machining of ferrous materials, diamond tools are easy to graphitize due to chemical reactions with ferrous materials, which can cause severe tool wear. The sharpness of the original cutting edge therefore cannot be maintained to machine mirror-level surface roughness. It cannot through a high-efficiency and low-cost way to obtain the workpiece surface integrity with high quality. Studying the wear mechanism of diamond tools and wear suppression methods is very important to improve the cutting efficiency of ultra-precision machining. In the present research, wear mechanisms and suppression schemes in diamond tools turning ferrous materials are reviewed and focusing on three major wear mechanisms and four effective suppression methods. In the end, this paper discusses the magnetism property of diamond-turnable materials, and introduces the feasibility of the magnetic field-assisted scheme to suppress diamond tool wear (DTW).

Investigation on controlling diamond tool edge and wear by ultrasonic vibration

Ultra-precision diamond cutting finds wide applications in various areas such as freeform optics, micro-structure arrays and high precision molds. Except for process parameters, machined surface quality is also directly influenced by the state of cutting tool edge. In this paper, a novel method for controlling the tool edge by multi-axis ultrasonic vibration is investigated. Kinematic analysis shows that the effective edge radius can be reduced and varied periodically, which indicates a sharpening effect of the tool. At the first step, numerical simulations including geometrical modelling and molecular dynamics are conducted to lay the theoretical foundation and study the effects of both the process parameters and the material response compared with the traditional ultrasonic vibration assisted cutting. Then, diamond turning, as an experimental approach, is performed to make the final validation of the proposed method based on the analysis of surface roughness, chip formation and tool wear.

Surface formation under the conditions of electroerosion grinding with variable polarity of electrodes

The contact zone is the area of mutual penetration of the cutting edges into the processedmaterial and the protrusions of the materials in the gaps between the grains. The parameters of thestate of the zone include its size and shape, the ratio of cut and uncut parts of metal in each area ofthe zone, the physical processes of formation, including: chipping, heat generation, plasticdeformation of the material, tool material wear and damage, physical and chemical effects oncooling lubricants.The formation of the processed surface in the conditions of electroerosive diamond grindingwith variable polarity of electrodes in the cutting zone is investigated in the article. A physicalmodel of diamond tool wear has been developed considering the erosion processes affecting thewheel connection. The construction takes into account dimensional wear, processes of chipping andpulling out single abrasive grains from the bond, under the action of the components of cuttingforces, considering the probability of grain contact with metal, the size of wear sites and the actualdepth of microcutting.The obtained ratios allow us to directly determine the probability of contact of the cut chipsfrom the body, formed by the cutting edge of the grain, with the bond surface of the grinding wheel.When solving the problem of the probability of contacting the set of chips formed by the set ofedges of the grains lying in the working layer of the tool, it is also necessary to use the probabilityof the density distribution along the depth.The type of the obtained ratios directly shows that a significant part of the chips formed bythe cutting edges in contact with the rough surface of the workpiece are short and do not come intocontact with the ligament until separation from the body of the workpiece, even without shrinkage.The obtained relations can be used in solving the corresponding problems of grinding theperiphery of the circle, for example, round external grinding. With a clearer description of theprocess, it is necessary to directly apply the nonstationary representation, taking into accountadditional nonstationary ones, introduced by the trajectories of the cutting edges as a function of theangle of rotation of the circle and the part in the process of their interaction.

Machinability of Zirconia Toughened Mica Glass Ceramics for Dental Restorations

Objective: For a dental material to be machinable for CAD/CAM technology, it must offer convenient machining, under a given set of cutting conditions. Quantitative evaluation of machinability has been assessed in literature through various parameters such as tool wear, penetration rates, surface roughness, cutting force and power. A machinable ceramic will typically demonstrate a higher tool penetration rate with signs of reduced diamond tool wear and edge chipping. The purpose of this in vitro study was to evaluate the feasibility of machining an experimental ceramic, 20 wt.% zirconia reinforced mica glass ceramics (G20Z) for indirect dental restorations and compare the tool penetration rates of G20Z to commercially available dental ceramics, Presintered Zirconia (PSZ) and IPS emax CAD. Material and Methods: Precursors of base glass (SiO2 -Al2O3 -K2O -MgO-B2O3 -F) were melted at 15000C for 2 h in a platinum crucible and quenched in deionised water. The glass frit was ball milled with 20 wt. % YSZ (G20Z) and subject to two stage heat treatment in a muffle furnace. Specimens of G20Z (12 X 2 mm) were evaluated for their feasibility of machining under varying spindle speed, depth of cut, and feed rates. Influence of depth of cut, spindle speed and feed rate (vc=8000-16000 rpm, d=0.4-0.8 mm, f=0.1- 0.3 mm/tooth) on cutting forces, material response, surface roughness and tool wear were investigated. Tool penetration rates, tool wear and margin chipping were also evaluated and compared with Pre-sintered Zirconia (PSZ) and e.max CAD in a custom dental milling surveyor at 30,000 rpm with a load of 0.98 N under water lubrication for 6 min. Tool penetration rates were calculated as the ratio of length of cut and milling time with a measuring microscope and scanning electron microscope was used for tool wear and edge chipping. ANOVA and Tukey Kramer tests were used for statistically comparing the means of each group. Results: Spindle speed and feed rate play a significant role in influencing surface roughness, thrust force, cutting forces and tool wear. Penetration rates of G20Z (0.32 ±0.12 mm/min) was significantly greater than PSZ (0.26 ±0.06 mm/min) and IPS e.max CAD (0.21 ±0.05 mm/min). SEM observations reveal tool abrasion and edge chipping regardless of the ceramic type. Conclusion: High spindle speeds delivers low cutting forces with an average surface roughness of 1.61 µm, with abrasive wear of the tool insert and brittle fracture of zirconia mica glass ceramic composites. G20Z with its machinable nature demonstrates greater tool penetration rates than PSZ and IPS e.max CAD. Tool wear and edge chipping is seen in all the investigated ceramics. Keywords Machinability, Dental Ceramics, Mica Glass-Ceramics, Dental Zirconia, Tool penetration rates.

Tribological performance and wear mechanism of smooth ultrananocrystalline diamond films

• HFCVD is used to synthesize UD-MCD, UD-UNCD, UD-MCD/UD-UNCD, BD-MCD, BD-UNCD, BD-MCD/BD-UNCD films on WC-Co substrates. • Growth mechanism of UNCD with high carbon concentration and low gas pressure in hydrogen-rich chemistry are illustrated. • Undoped and boron doped UNCD coatings are firstly applied on WC-Co micro drills to improve the surface smoothness. • Both boron doping and middle layer MCD contribute to the strong adhesive level of UD-MCD/UD-UNCD and BD-MCD/BD-UNCD. • The UD-MCD/UD-UNCD, BD-UNCD and BD-MCD/BD-UNCD coated PCB micro drills show superior cutting performances. 5G printed circuit boards (PCBs), composed of glass fiber, epoxy resin and ceramic, are a kind of difficult-to-machine material. The manufacture of massive high-quality micro holes on 5G PCBs raise high requirements on the tool life and machining precision of PCB micro drills. Chemical vapor deposition (CVD) diamond coatings can be used as effective protective films on PCB micro drills. The surface smoothness and coating-substrate adhesion of diamond coated micro drills are two important factors affecting the drilling performances. Different from previously reported microcrystalline diamond (MCD) or nanocrystalline diamond (NCD) coating types on cutting tools, undoped (UD-) and boron doped (BD-) ultrananocrystalline diamond (UNCD) coatings with higher surface smoothness are firstly applied on PCB micro drills to reduce the friction and cutting resistance and improve the cutting performances while machining PCBs. Moreover, different from the usual argon-rich gas atmosphere for UNCD synthesis, the synthesis mechanisms of UD-UNCD and BD-UNCD with hydrogen-rich atmosphere adopting HFCVD method are clarified. Sufficiently high renucleation rate of diamond crystallites, long mean free path of reactive precursor species and high removal rate of non-diamond carbon phases lead to the successful synthesis of UNCD films. UDMCD, UD-UNCD, UD-MCD/UD-UNCD, BD-MCD, BD-UNCD, and BD-MCD/BD-UNCD, were synthesized on PCB micro drills using HFCVD. The tribological performances and wear mechanisms of these different diamond coatings were studied systematically. The dominant wear mechanism causing tool wear and fracture of diamond coated micro drills in high-speed machining PCBs is abrasive wear. The degree of abrasive wear while machining PCBs are mainly determined by the surface smoothness, surface roughness and coefficient of friction of diamond coatings. The top layer UNCD with tiny grain size leads to the improvement of surface smoothness and tribological properties, which enhance the chip evacuation capacity and reduce the tool wear. Besides, both boron doping and middle layer MCD can contribute to the strong coating-substrate adhesion. Therefore, BD-MCD/BD-UNCD coated micro drill exhibits the best cutting performances while machining PCBs.

Suppression of Polycrystalline Diamond Tool Wear with Mechanochemical Effects in Micromachining of Ferrous Metal

A mechanochemical effect is investigated to reduce diamond tool wear by means of applying a surfactant to low-carbon magnetic iron during diamond turning. Orthogonal microcutting demonstrates the manifestation of the mechanochemical effect through the reduction of cutting forces by 30%, which supports the notion of lower cutting temperatures for reduced tribo-chemical wear. This is affirmed by the reduction in tool flank wear by up to 56% with the mechanochemical effect during diamond turning. While wear suppression increases by 9.4–16.15% with feeds from 5–20 μm/rev, it is not proportional to the reduction in cutting forces (31–39.8%), which suggests that the reduction in cutting energy does not directly correspond with the reduction in heat energy to sustain tribo-chemical tool wear. The strain localization during chip formation is proposed to serve as a heat source that hinders the wear mitigation efficiency. Finite element simulations demonstrate the heat generation during strain localization under the mechanochemical effect, which counteracts the reduced heat conversion from the plastic deformation and the transfer from tool–chip contact. Hence, this paper demonstrates the effectiveness of the mechanochemical method and its ability to reduce tool wear, but also establishes its limitations due to its inherent nature for heat generation.

Вплив режимних параметрів дискової машини на зношення алмазного інструменту

Each technology of extraction of block natural stone has its advantages and disadvantages. Promising areas for improvement of block stone extraction technology are the improvement of non-explosive technologies that do not affect the development of man-made cracks. The publication considers a new technology of block stone extraction, which is based on the use of disk machines in combination with a diamond-rope machine. One of the technologies is the extraction of natural stone using disk machines. Due to a number of advantages, this technology has the prospect of widespread use. This technology is used in China in the conditions of upland deposits. In Ukraine, this technology is beginning to be tested, due to which a significant number of aspects remain unexplored. So, for example, it is necessary to select mode parameters of cutting for each deposit of block natural stone individually. The paper conducted a study of the wear of diamond tools on disk machines when changing the mode parameters of cutting. The experiments were performed on a disk machine with a saw diameter of 2,5 m. The diamonds were 40/50 mesh with a concentration of 50 % (the concentration is 4,4 carats of diamonds per cm3 of soldering volume), these solders are recommended for sawing solid materials. Water consumption was 120 l / min Cutting experiments were performed both in the mode of cutting «on the feed» and «against the feed». Cutting was performed five times in both directions. The obtained data were averaged. The working feed rate varied in the range of 0,3–0,6 m / min and the cutting depth was 3–8 cm. The dependences described by second-order polynomials were obtained.

Suppression of tool damage in ultraprecision diamond machining of stainless steel by applying electron-beam-excited plasma nitriding

Mirror surface machining of stainless steel with single-crystalline diamond tools is proposed in this study by applying a new nitriding method, called electron-beam-excited-plasma (EBEP) nitriding, to workpiece surfaces as pretreatment. It is well known that mirror surface finish of steel workpieces by conventional diamond cutting is unachievable owing to rapid tool wear. Nitriding of steel workpieces has been one of the several attempts to prevent the rapid tool wear of diamond tools. It has been reported that the rapid tool wear is caused by thermochemical interaction between diamond and steel, and that the wear can be greatly reduced by nitriding of steel. However, hard compounds formed on the outmost surfaces of workpieces by the conventional nitriding methods can cause micro-chippings of cutting tools. The authors has recently developed a new nitriding method called EBEP nitriding, in which a high dissociation rate for nitrogen molecules is achieved using the electron-beam-excited-plasma, and iron-compounds-free nitriding has been realized. Therefore, the EBEP nitriding is applied to a typical mold material, modified AISI 420 stainless steel, aiming at suppressing the micro-chippings as well as the thermochemical tool wear during diamond cutting of the stainless steel. The conventional ion nitriding and the gas nitrocarburizing are also applied to the same stainless steel in comparison. Chemical components of the nitrided workpiece surfaces are analyzed by an electron prove micro-analyzer (EPMA) and an X-ray diffraction (XRD) in advance, and turning experiments are conducted with single-crystalline diamond tools. Subsequently, changes in cutting forces and roughness of finished surfaces and tool damages after the turning experiments are evaluated. Finally, mirror surface machining by using the EBEP nitriding is demonstrated, and its advantages and disadvantages in the diamond cutting of stainless steel are summarized in comparison with the conventional nitriding methods.

Influence of Cerchar hardness index of hard rock granite on wear of diamond tools

Wear is an important technical and economic parameter in the assessment of cutting performance of diamond tools. It is influenced by many parameters and, the material hardness of the cut surface is one needs to be examined. The current work presents a study of correlation between the Cerchar hardness index (CHI) of hard granite rocks and wear of diamond wiresaw beads. Further the correlation between CHI and wear of large diameter circular disc cutter segments is investigated. Moreover, the linear least regression models for the dataset is developed to grasp the statistical relationship between rock hardness and diamond tool wear. This work may provide significantly valuable insights to the stone and diamond tool manufacturing industry.