Diamond Tool Wear Research Articles

Molecular Dynamics Simulation Study on Diamond Tool Wear in Cutting Aluminum-Based Workpieces

The problem of diamond tool wear is the bottleneck for machining large metal reflector with ultraprecision cutting method. In this paper, the author performed simulation study on diamond tool wear in machining large metal reflectors, and established a molecular dynamics simulation model for dynamic simulation of tool wear; and found that in the simulation process the change in cutting speed and cutting depth had definite effect on the tool wear, and the main factors affecting the tool wear was the cutting distance.

Research on the Wear Characteristics of PDC Diamond Cutting Tools for Natural Granite

PCD diamond cutting tools which named sintering diamond tool is the main cutting tool of the natural granite, the cutting characteristics of that have great influence on machining efficiency and machining quality. At present, most scholars are relatively mature on the research of diamond tool wear condition by the physical attributes of the PCD diamond tool and physical components of natural stone material. This paper studies the impact of cutting parameters on the tool wear, optimization of process parameters.

Influence of Tungsten-Carbide and Cobalt on Tool Wear in Cutting of Cemented Carbides with Polycrystalline Diamond Tool

The influence of the tungsten-carbide (WC) particle size and Co contents of cemented carbides on polycrystalline diamond tool wear during turning was investigated experimentally. The main results obtained were as follows. (1) Tool wear increased with increasing Co content. (2) It is important to cut off the binder between the WC particles and the Co. (3) Cemented carbides containing small WC particles are more effective than cemented carbides containing large particles.

Finite Element Analysis of Ultrasonic Vibration Assisted Turning of Ferrous Metals

Ultrasonic vibration assisted turning has significant improvements in processing of intractable materials compared to conventional turning. This paper presents a theoretical investigation of tool wear in single point diamond turning of ferrous metals based on numerical simulation. Finite element modeling and simulation of ultrasonic vibration turning process were performed, aimed at optimizing a series of technological parameters in the process of machining, reducing tool wear and improving surface quality as much as possible. The results revealed that the cutting speed and depth of cut are two crucial factors for tool wear, unlike the other parameters of vibration frequency, amplitude and flank angle. Moreover, this technological measure has observably decreased the cutting force and cutting temperature, so as to obtain superior surface finish.

Thermo-chemical wear model and worn tool shapes for single-crystal diamond tools cutting steel

An Arrhenius-type thermochemical wear model proposed by past researchers is evaluated for predicting diamond tool wear when machining low carbon steel. Tool temperature values are determined using finite element modeling. These temperatures are related to tool wear measured after diamond turning tests on a low carbon steel workpiece to determine constants in the Arrhenius-type model. Measured tool wear shows a transition in worn tool shape from low speed (1mm/s) to high speed (4m/s) machining tests. Model results show a minimum value of wear per cutting distance occurs at a cutting speed of 2.5m/s. The model also gives an activation energy between 25.0kJ/mol and 29.3kJ/mol. In addition, this model is used to explain experimental results obtained by others researching chemical wear of diamond.

Diamond tool wear during ultra-high precision machining of rapidly solidified aluminium RSA 905

Aluminium alloys such as AA 6061-T6 are used to create forming optical surfaces in mould cavities for the injection of plastic optical components. However, 6061-T6 aluminium is characterised by its coarse microstructure which results in inconsistent performance of the cutting tool in terms of tool wear. In this study, a modified grade of 6061 aluminium, called RSA 905, is diamond machined. RSA 905, which enjoys a finer microstructure achieved using a rapid solidification melting process, is diamond turned at different feed rates and a constant cutting speed and depth of cut. This paper reports on the tool wear mechanisms encountered when turning the rapidly solidified aluminium grade using mono-crystalline diamond inserts on an ultra-high precision machining centre. The cutting speed and depth of cut were set at 2000rpm and 25μm, respectively. The tool wear on the flank and crater surfaces was observed using scanning electron microscopy. In addition, acoustic signals emitted during machining were acquired to monitor the tool wear. Although the RSA 905 alloy possesses an increased ultimate strength, its diamond-machinability is found to be high and tool wear is absolutely low even after relatively high cutting distances. However, the tool wear measurement results show that the tool wear tends to be more intensive at the middle value of the feed rate.

Experimental investigation on the surface integrity in machining for Si<SUB align="right">3N<SUB align="right">4 engineering ceramics

Conventional grinding and rotary ultrasonic grinding machining (RUGM) are applied in precision machining for Si3N4 engineering ceramics mostly. The surface integrity is of great difference with different processing operation. In the paper, the differences of surface integrity by the two machining methods were investigated. The comprehensive evaluation for surface integrity parameters of surface microstructure flaws and mechanical properties was investigated. The surface roughness, surface edge-chipping and surface residual stresses were observed and detected. The experiments results were analysed and discussed based on the material removal process, the motion trail of diamond grits, cutting force and tool wear for the different machining methods. The results show that the surface roughness and the residual stress for RUGM are worse than that for conventional grinding, since the effect of indentation fracture is more notable. However, the scope of edge-chipping is smaller for RUGM than that for conventional grinding due to lower cutting force.

Effects of surface modifications on steel's machinability in single-point diamond turning

Surface modifications are employed in single-point diamond turning of steels to reduce the chemical-reactive wear of diamond tool to an acceptable degree. Different thermochemical modifications, i.e., plasma nitriding, boronising, siliconising, boronitriding and compound boronising-aluminising, are designed to bond the atoms of transition metal elements in steels with the chosen elements. The effects of various surface modifications on steels machinability are investigated mainly in terms of tool wear and workpiece surface quality. It is found that nitrogen (N) is beneficial to improve the tool life; N, silicon (Si) and aluminium (Al) may help to obtain a mirrorlike surface; B plays the negative role in steel's machinability in single-point diamond turning. Developing suitable-for-diamond-cutting materials on which nanometric surface finish can be achieved is proposed according to the role of the permeated elements.

G131011 無酸素銅精密切削におけるダイヤモンドエ具損耗特性 : 刃先先端部の窒素不純物と損耗の関係([G131]生産加工・工作機械部門,一般セッション)

G131011 無酸素銅精密切削におけるダイヤモンドエ具損耗特性 : 刃先先端部の窒素不純物と損耗の関係([G131]生産加工・工作機械部門,一般セッション)

Hybrid laser ablation-single point diamond turning machining process for CVD-silicon carbide ceramics

Silicon carbide (SiC) is an advanced engineered ceramic material appropriate for operation in extreme environments. Manufacture of components from this material is extremely challenging due to its high hardness, brittle characteristics and poor machinability. Severe fracture can result when machining SiC due to its low fracture toughness. However, prior research has shown that ductile regime machining of silicon carbide is possible. This paper reports improvement of the surface quality of a chemically vapour deposited (CVD) polycrystalline SiC (3-C) material by using a hybrid laser ablation – single point diamond turning (SPDT) machining process. This work also emphasised increasing the material removal rate (MRR) and minimising the diamond tool wear. Besides the surface finish analysis, subsurface damage analysis was also done on the laser ablated and single point diamond turned surfaces to compare the nature of these processes in terms of subsurface damage.

Tool Wear of Diamond Tools in Ultrasonic Vibration Turning Titanium Alloys

Titanium alloys, as difficult-to-cut materials, have poor machinability due to their superior mechanical properties, heat resistance and corrosion resistance. High cutting temperature and great cutting force that will greatly accelerate tool wear often occurs in titanium alloys cutting process. In this paper, an ultrasonic vibration turning method was used to lower diamond tool wear during TC4 titanium alloy turning process. Ultrasonic vibration turning tests were carried out with various cutting parameters. Experimental results indicated that there’s a significant reduction of the wear rate of diamond tools by means of ultrasonic vibration in TC4 turning process. For ultrasonic vibration turning, spindle speed, the amplitude and frequency of vibration of the tool are the greatest impact of tool wear, followed by feed rate, then the cutting depth.

Tool wear and its effect on surface roughness in diamond cutting of glass soda-lime

For the technology of diamond cutting of optical glass, the high tool wear rate is a main reason for hindering the practical application of this technology. Many researches on diamond tool wear in glass cutting rest on wear phenomenon describing simply without analyzing the genesis of wear phenomenon and interpreting the formation process of tool wear in mechanics. For in depth understanding of the tool wear and its effect on surface roughness in diamond cutting of glass, experiments of diamond turning with cutting distance increasing gradually are carried out on soda-lime glass. The wear morphology of rake face and flank face, the corresponding surface features of workpiece and the surface roughness, and the material compositions of flank wear area are detected. Experimental results indicate that the flank wear is predominant in diamond cutting glass and the flank wear land is characterized by micro-grooves, some smooth crater on the rake face is also seen. The surface roughness begins to increase rapidly, when the cutting mode changes from ductile to brittle for the aggravation of tool wear with the cutting distance over 150 m. The main mechanisms of inducing tool wear in diamond cutting of glass are diffusion, mechanical friction, thermo-chemical action and abrasive wear. The proposed research makes analysis and research from wear mechanism on the tool wear and its effect on surface roughness in diamond cutting of glass, and provides theoretical basis for minimizing the tool wear in diamond cutting brittle materials, such as optical glass.

Novel auto-regressive measurement of diamond tool wear in ultra-precision raster milling

In this paper, a new auto-regressive algorithm is proposed to reconstruct 3D topographic surface for diamond tool wear, using its in-process image. First, based on digital image processing technique, tool wear lands are separated from a tool wear image captured by a CCD camera under a 100X optical system; Second, a traverse search method of arc translation is put forward to eliminate feigned wear lands, and a least square polynomial method is adopted to fit inner- and outercontours of the wear lands, self-adaptively filtering noises and connecting the discontinuous wear lands; Finally, the autoregressive calibration method is developed to reconstruct its 3D topographic surface. The wear land is extracted selfadaptively, and the wear area, maximal wear width, average wear width and worn volume can be determined automatically by the algorithm. The reconstructed 3D topography of the tool wear land can be identified, based on the tool wear image captured by SEM. The result indicates that the method is capable of reconstructing 3D topography of the tool wear land and provides a possibility for in-process 3D-wear measurement in ultra-precision raster milling (UPRM) and the algorithm reliability is validated finally. And the influence of tool wear on surface roughness is discussed.

Adhesion of Silicon to the Tool during Diamond Cutting Silicon by Molecular Dynamics

Wear of diamond tool is also very serious, which affects the surface quality of the machined work material, even if ductile mode where an undeformed chip thickness is at a nanoscale is used. During the cutting process, the crystal structure in the cutting zone is destroyed under the high pressures applied by the diamond tool. The silicon atoms adhering to the tool surface reconstruct to be in a crystal state under the effect of adhesion and pressures.

Influence of Hydrogen, Carbon Dioxide, and Alloy Content on Pore Formation in the White Layer of Alloyed Steels

Gaseous nitriding and nitrocarburizing of steel have found new applications in the area of ultra-precision machining of steel with mono-crystalline diamond tools. Steel is normally not diamond machinable because serious chemical reactive wear of diamond tool occurs. The wear can be reduced significantly if the machining is carried out in the white layer of nitrided or nitrocarburized steel, since the chemical reactivity of the white layer is lower compared to the steel substrate. For this application a thick white layer with low porosity is desirable. To produce such white layers the nitriding and nitrocarburizing processes should be specifically adapted. In the present work the influence of hydrogen and carbon dioxide in the process atmosphere on pore formation in the white layer during nitriding and nitrocarburizing was investigated experimentally. The experiments of gaseous nitriding and nitrocarburizing were carried out with varied process atmosphere on alloy steel grades. The generated surface layers were characterized by glow discharge optical emission spectroscopy (GDOS) and by optical microscopy. The results showed that low partial pressure of hydrogen in the nitriding atmosphere and strong nitride-forming elements in the steel are positive in suppressing pore formation, while carbon dioxide promoted pore formation in nitrocarburized white layer.

Ultrasonic Assisted Diamond Turning of Hardened Steel for Mould Manufacturing

Diamond turning of steel parts is conventionally not possible due to the high tool wear. However this process would enable several different applications with high economical innovative potential. One technology that enables the direct manufacturing of steel components with monocrystalline diamond is the ultrasonic assisted diamond turning process. This technology has been investigated over the years within the Fraunhofer IPT and is now commercialized by its spin-off company son-x. Surface roughness in the range of Ra < 5 nm can be achieved and the diamond tool wear is reduced by a factor of 100 or higher. In order to prove the industrial suitability of the process, two aspherical shapes and one large spherical geometry have been manufactured. The possible form accuracies and surface roughness values will be described in this paper, as well as the tool wear. The goal was to achieve optical surface roughness and a shape accuracy below 300 nm.

Chip Formation in Ultra-Precision Machining of Nitrocarburized Steels

For the replication of optical glass or plastic components moulding inserts with surface roughness in the nanometre range and form accuracy in the micron or sub-micron range are needed. Despite these requirements the applied moulding insert material has to suit further needs like high temperature stability and resistivity against abrasive and chemical wear. To satisfy the specific requirements of replication processes steel alloys can be heat treated in a way to meet these demands. Unfortunately, these steel alloys cannot be machined with single crystal diamond tools because catastrophic diamond tool wear occurs. In recent years good progress in the field of ultra precision machining of steel has been made by nitrocarburizing the steel alloy. This leads to a sub-surface compound layer which is diamond machinable with surface roughness Sa < 10 nm and reduced diamond tool wear. But the ultra precision machining of these nitrocarburized steels introduces new challenges caused by the high hardness of the compound layer. Typical values are about 1200HV0.025. Therefore, this paper presents results from ultra precision machining processes focusing on the material behaviour during the cutting process. Influences of depth of cut and material composition on the surface generation can be found by evaluating chip formation and the resulting chips. Furthermore, the sub-surface of ultra precision machined steels is characterized by metallographic analysis to evaluate the influence of the nitrocarburizing process on ultra precision machining. In conclusion this paper presents the results for a deeper understanding of the material removal mechanisms in ultra precision machining of nitrocarburized steels.

Single Point Diamond Turning of Calcium Fluoride Optics

This paper aims to develop a cost-effective diamond turning process to obtain nanosmooth CaF2 optics. Diamond tool wear was also carried out through a number of cutting trials. Three CaF2 specimens (diameter of 50 mm and thickness of 5 mm, crystal orientation of (111)) were diamond turned on an ultra precision lathe (Moore Nanotech 350UPL) by a number of facing cuts. In the cutting trials feed rate varied from 1 μm/rev to 10 μm/rev. White spirit mist was used as the coolant. Cutting forces were measured by a dynamometer (Kistler BA9256). Surface roughness of the CaF2 optics and tool flank wear were measured by a white light interferometer (Zygo Newview 5000) and a scanning electron microscope (FEI Quanta 3D FEG), respectively. It was found that using a feed rate of 1 μm/rev surface roughness Ra of 2 nm could be obtained. When the ratio of the normal cutting force to the tangential cutting force was lower than 1 tool wear would initiate. In diamond turning of calcium fluoride abrasive wear was the main tool wear mechanism. Using white spirit mist as thecoolant could avoid generation of thermal type brittle fracture on the machined CaF2 surfaces.

Progressive Tool Wear in Diamond Cutting of Glass Soda-Lime

For the technology of diamond cutting of optical glass, the high tool wear rate is a main reason for hindering the practical application of this technology. Minimizing the tool wear is of great significance in order to achieve the satisfactory surface quality and dimensional accuracy. For in depth understanding of the tool wear mechanisms, experiments of diamond turning with cutting distance increased gradually was carried out on soda-lime glass in this work. Experimental results indicate that the flank wear was predominant in diamond cutting glass and the flank wear land was characterized by micro-grooves, some smooth crater on the rake face was also seen. The mainly mechanisms inducing tool wear in diamond cutting of glass are diffusion, mechanical friction, thermo-chemical action and abrasive wear.

Diamond tool wear properties in precision turning of oxygen-free copper disks

Diamond tool wear properties in precision turning of oxygen-free copper disks