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Ultra-short Pulsed Laser Conditioning of Metallic-bonded Diamond Grinding Tools
摘要： A novel approach for machining of cylindrical ultra-hard materials with a highly defined contour is presented. Diamond grinding tools with complex geometry are manufactured with picosecond orthogonal and quasi-tangential laser ablation. Hitherto, laser manufacturing required a special axis configuration and optical beam deflection devices are utilized. Here, strategies and processes on a scanhead-free configuration using ultra-short pulsed laser are discussed enabling straight-forward implementation in industry. This rapid and flexible approach for the production of master tools for industrial grinding processes reveals benefits compared to conventional techniques. The manufacturing time is comparable to standard processes, however, increased grain protrusion is attained with the presented laser sharpening strategy. An ablation study for maximal material-removal rate reveals the impact of wavelength, strategy, and repetition rate at high average power up to 100 W. A combined laser manufacturing routine enables an ablation rate of 35 mm3 min?1 and a maximal geometric deviation of 3 μm after finishing. The final grinding tools are sharpened by a radial laser process preferentially removing the metal-based binding material. Hence, high-precision diamond grinding wheels with a mean error of smaller 1 μm over millimeter-sized contours can be manufactured. The meta-stable diamond structure persists and is assessed via Raman spectroscopy studies at laser cut grains.
关键词： Raman spectroscopy,laser manufacturing,diamond grinding tool,ultra-short pulses,precision machining,laser conditioning
更新于2025-09-19 17:13:59
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Coupled Thermal-Mechanical Analysis of CO<sub>2</sub> Laser Irradiation on Fused Silica
摘要： To grind fused silica in ductile mode, it was proposed to repair surface and subsurface micro cracks of fused silica by CO2 laser irradiation. However, excessive residual stress remains on the surface because the melt fused silica on the surface quenches in air. It causes the critical depth of cut for ductile grinding fused silica to be smaller than 0.2μm. To investigate the distribution of the residual stress and look for an optimal manner of irradiation to control residual tensile stress, a numerical model of was built for simulating the dynamic behavior of fused silica when irradiated by CO2 laser. Laser energy absorption, heat transmission, viscoelastic behavior of fused silica and thermally induced stress were considered in the numerical simulation. The results show how the residual stress is formed and distributed. We found that an appropriate control of the temperature field as a function of time and position in the laser process is the key to reduce the residual stress. Therefore, three kinds of processes were proposed to reduce residual tensile stress on the surface of fused silica introduced by laser irradiation. The residual stress distributions of these three processes were compared by numerical analysis to decide a better method of laser irradiation.
关键词： fused silica,laser irradiation,ductile grinding,viscoelastic,residual stress
更新于2025-09-16 10:30:52
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Hybrid laser assisted machining: a new manufacturing technology for ceramic components
摘要： Silicon nitride is a high-performance ceramic used for high-temperature structural applications due to its elevated strength, fracture toughness and corrosion resistance. These properties make this material extremely difficult to machine, leading to component costs that can be prohibitive in many fields where its characteristics could provide improvements in performance. In order to overcome manufacturing limitations, a new technique is proposed in this paper: a hybrid solution that combines laser and conventional cutting tools where the laser source induces controlled cracking into the surface of the material. By properly selecting the laser parameters (laser power, scanning speed, etc.), the crack depth can be smaller than the machining depth of cut. Cracking can be performed in a preceding phase so that no thermal load is induced in the inserts, while maximum cutting load is reduced, thus increasing tool life.
关键词： Silicon Nitride,laser treatment,hard ceramic components,hybrid machining,grinding
更新于2025-09-12 10:27:22
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A Model for Predicting the Geometry of Crater on Grinding Wheel Surface Ablated with a Single Pulsed Laser
摘要： In this paper, a three dimensional transient heat transfer model for predicting the 3D geometry of crater and its cross sectional profile on grinding wheel surface ablated by a single pulsed Nd: YAG laser is covered. The model considers the heterogeneity of wheel structure, the variation of energy in a pulsed laser input to the wheel, heat transfer by conduction, convection, radiation and the thermo-physical and optical properties of bond and grit while predicting the temperature distribution in the irradiated region using COMSOL Multiphysics? 5.2 package. From this temperature distribution, the shape of crater was predicted. Crater depth predicted was validated with the published results confirming the suitability of this model for predicting the shape of crater in single pulsed laser ablation of wheel surface. Post modeling analysis gives insights of the process mechanism of laser dressing and the parameters affecting the crater geometry. Future scope and implementation of this model is discussed in detail.
关键词： single-pulse laser ablation,laser dressing of grinding wheels,wheel structure model,crater geometry
更新于2025-09-12 10:27:22
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Analysis of diamond wheel wear and surface integrity in laser-assisted grinding of RB-SiC ceramics
摘要： Laser-assisted grinding provides a promising solution for achieving cost-e?cient machining of hard and brittle materials. However, the heat generated by laser may cause the wear of diamond grinding wheel, including the wear of both diamond grits and bond material. Consequently, wheel wear has a knock-on e?ect on the ground surface roughness. Moreover, the laser irritation may also induce damage in the machined surface. This paper focuses on the investigation of wear of diamond grinding wheel and surface integrity in laser-assisted grinding of RB-SiC ceramics. Di?erent temperatures were obtained by setting the laser power to explore the in?uence of heat on wheel wear and surface integrity. The wear modes and mechanism of the diamond grits and bond material were analyzed by combination of SEM detection and energy dispersion spectrum analysis. The results revealed that adhesion and pullout of diamond grits in laser-assisted grinding were the remarkable di?erence from those in conventional grinding due to the thermal softening of both RB-SiC specimen and bond material of the grinding wheel. Surface roughness was then improved owing to the increase in active grits. The Raman spectra of the machined surface also revealed di?erent stress conditions and microstructures of the Si and SiC Phase in RB-SiC ceramics. These results provided insight on quality control in laser-assisted machining of RB-SiC ceramics.
关键词： Grinding wheel wear,Surface integrity,Laser-assisted grinding,High temperatures
更新于2025-09-11 14:15:04
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Grinding performance improvement of laser micro-structured silicon nitride ceramics by laser macro-structured diamond wheels
摘要： Silicon nitride ceramics are widely used in various industrial ?elds because of their excellent characteristics: high hardness, high elastic modulus, abrasion resistance, and high heat resistance. Diamond wheel grinding is the predominant and most productive method to machine silicon nitride ceramics. However, a lot of heat is generated due to high friction between a diamond grinding wheel and extremely rigid silicon nitride during grinding. This causes surface/subsurface damage, wheel wear, etc., which impairs the surface quality of silicon nitride. This impairment can restrict the use of silicon nitride ceramic components. To improve the surface quality and service life of grinding wheels, a laser macro-micro combination structured grinding (LMMCSG) method was presented. The results indicated that the grinding force ratio and surface roughness when using LMMCSG were respectively 31% and 40% lower than the grinding force ratio and surface roughness when using conventional grinding. Moreover, the LMMCSG method e?ectively reduced the wheel wear and workpiece subsurface damage.
关键词： Macro–micro combination,Laser structured grinding,Wheel wear,Silicon nitride ceramic,Grinding force ratio,Surface roughness
更新于2025-09-11 14:15:04
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Effects of laser-assisted grinding on surface integrity of zirconia ceramic
摘要： Zirconia ceramics has an important position in the field of biomaterials because of excellent mechanical properties. Because of abrasive resistance and hardness, conventional machining of zirconia ceramic is difficult and time-consuming. A nontraditional hybrid laser-assisted grinding (LAG) system combining laser and cubic boron nitride (CBN) grinding wheel was developed for machining zirconia ceramic. This hybrid system utilizes the outstanding thermostability of zirconia ceramic: The material present on the cutting path is rapidly removed by local laser heating and grinding wheel. A combined theoretical and experimental study was performed to evaluate different modes of machining of zirconia ceramic. The machining parameters were predicted by numerical analysis. The surface quality, surface morphology, and subsurface damage of zirconia ceramic specimens were analyzed and compared. The results show that LAG can easily achieve ductile regime grinding in the same machine tool. Compared with conventional grinding, the surface integrity of zirconia ceramic was significantly improved by the LAG process. LAG could achieve ductile regime grinding with a large depth-of-cut. It changes the machinability of zirconia ceramic.
关键词： Surface quality,Surface morphology,Laser-assisted grinding,Zirconia ceramic,Subsurface damage
更新于2025-09-11 14:15:04
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Study on magnetic abrasive finishing of AlSi10Mg alloy prepared by selective laser melting
摘要： Selective laser melting (SLM) technology is playing an increasingly important role in today’s manufacturing industry. However, the surface quality of SLM samples is relatively poor and cannot be directly applied to industrial production. Therefore, this paper focuses on the post-treatment process of SLM AlSi10Mg alloy. First, the rough machining is performed by a grinding process (GP), and then, the magnetic abrasive finishing (MAF) is used for finish machining. The experiment results show that the combination of GP and MAF can effectively reduce the surface roughness and improve the surface quality of SLM AlSi10Mg alloy. The GP reduced the surface roughness to drop from 7 μm (after SLM forming) to about 0.6 μm, and the rough surface with defects such as spheroids and pits evolved into the fine surface with scratches and pores. The MAF reduced the surface roughness to a minimum of 0.155 μm, which resulted in excellent surface morphology. The surface hardness after the GP was higher, and the MAF reduced the hardness of the GP surface.
关键词： Grinding process,Hardness,AlSi10Mg alloy,Selective laser melting,Surface roughness,Magnetic abrasive finishing
更新于2025-09-11 14:15:04
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Performance evaluation and multi-response optimization of grinding-aided electrochemical discharge drilling (G-ECDD) of borosilicate glass
摘要： Machining of advanced glass ceramics is of great importance and is a challenging task for the modern industries. In this study, a new hybrid technique of grinding-aided electrochemical discharge drilling (G-ECDD) is attempted which combines the grinding action of a rotating abrasive tool and thermal melting action of electrochemical discharges to perform drilling of borosilicate glass. G-ECDD is performed using a normal electrochemical discharge machine set-up with a provision for using a rotating diamond-coated drill tool. The tool used is a hollow diamond core drill rather than the traditional solid abrasive tool. A spring-fed tool system was designed and developed to provide the tool-feed movement which will also help to maintain a balance between grinding action of diamond grits and thermal melting action of discharges. Preliminary experiments are conducted to identify the optimum spring force of the spring-fed system and tool rotational speed which can facilitate a balanced ECDM and grinding action for material removal. The effect of machining parameters like voltage, duty ratio, pulse cycle time and electrolyte concentration on material removal rate (MRR) and hole radial overcut (ROC) is investigated using response surface methodology (RSM). Duty ratio and voltage are found to be the most significant factors contributing MRR. Voltage and pulse cycle time are identified as the main factors controlling radial overcut of the drilled holes. Second-order regression models for MRR and ROC are developed using the data collected from the experiments using RSM. Grey relational analysis was used to optimize this multi-objective problem. A voltage of 90 V, duty ratio of 0.7, cycle time of 0.002 s and an electrolyte concentration of 3.5 M are found to be the best combination for optimizing the responses. Deterioration of bonding material and dislodging of diamond grits are found to be the major modes of tool wear during G-ECDD. The use of high-frequency pulsed DC increased the tool wear rate due to the less time available for heat dissipation between discharge cycles. Moreover, the wear at the end face of the tool will be accelerated due to the concentration of current density at edges during high-frequency operation. From the microscopic images of the machined surface, the material removal mechanisms involved in G-ECDD are found to be a combination of thermal melting by discharges, grinding action of diamond grits and high-temperature chemical etching effect of the electrolyte.
关键词： Electrochemical discharge machining,Response surface methodology,Tool wear,Radial overcut,Grey relational analysis,Material removal rate,Material removal mechanism,Grinding
更新于2025-09-11 14:15:04
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Dry-co-grinding of doped TiO2 with nitrogen, silicon or selenium for enhanced photocatalytic activity under UV/visible and visible light irradiation for environmental applications
摘要： TiO2 doped with nitrogen (N), silicon (Si), or selenium (Se) (N-TiO2, Si-TiO2, and Se-TiO2) were obtained by the integrated sol-gel and solvothermal method with short time of crystallization and low temperature. The UV/visible and visible light absorption and photocatalytic activity of these doped TiO2 materials were improved by a dry-co-grinding process with a short grinding time and low rotational speed (30 min at 200 rpm) to obtain N-TiO2/Si-TiO2 and N-TiO2/Se-TiO2 catalysts. The materials were characterized by XRD, Raman, BET surface area and porosity, XRF, SEM, TEM, FTIR-ATR, and UV/vis-DRS analyses. The photocatalytic activity of these materials was evaluated by the degradation of phenol under UV/visible and visible light irradiation. The integrated sol-gel and solvothermal methods with short time of crystallization (2 h) and low temperature (225 °C), and the dry-co-grinding process during 30 min at 200 rpm led to materials (N-TiO2/Si-TiO2 and N-TiO2/Se-TiO2) with higher specific surface area, a reduction in the band gap value, and an enhancement of the absorption in the visible light spectrum. Moreover, N-TiO2/Si-TiO2 and N-TiO2/Se-TiO2 exhibited higher photocatalytic activities for degradation of phenol under UV/visible and visible light irradiation than those obtained with the doped TiO2, synthesized TiO2 or TiO2 P25.
关键词： Doping TiO2,Titanium dioxide,Sol-gel,Co-grinding process,Solvothermal
更新于2025-09-10 09:29:36