Bronze-bonded Diamond Grinding Wheel Research Articles

Influence of grain concentrations gradients on the profiling behaviour of bronze bonded diamond grinding wheels

In this work, diamond grinding wheels are first manufactured with two different metallic bonds. These are a ductile and a brittle bronze. Two differently graded (varied grain concentration) grinding wheels and two non-graded reference grinding wheels are manufactured in each case. The mechanical properties of these are then determined. Subsequently, a method is presented that enables the profiling of graded grinding wheels. For this purpose, the grinding wheels are profiled with SiC rolls using different profiling parameters. The profile accuracy after profiling is analysed using contour profiles in polyurethane. In addition, the dressing ratio and the process duration of profiling are measured. These parameters are used to determine the economic efficiency of the profiling process. Finally, this provides a bond-dependent profiling process that can economically and reproducibly generate a target contour on a grinding tool.

Grinding performance evaluation of SiC ceramic by bird feather-like structure diamond grinding wheel

In recent years, the diamond grinding wheel has become the primary tool to process hard and brittle materials. A promising technology for enhancing grinding performance is surface-structured grinding wheels. A novel laser simulation bird feather-structured bronze bond diamond grinding wheel is suggested in this paper. It provides outstanding drag reduction and diversion effects since it is based on the structure of bird feathers. The bionic swallows' secondary feathers prototype was ablated on the bronze-bonded diamond grinding wheel by the pulse laser. The grinding processing mechanism of silicon carbide ceramics with a feather-like structured grinding wheel (FLSGW) was analyzed. The grinding performance of FLSGW, V-shaped structured grinding wheel (VSSGW), and a traditional grinding wheel (TGW) grinding silicon carbide ceramics were compared. The effect of FLSGW on the grinding force, workpiece surface quality, and wheel wear were investigated. The results show that FLSGW can reduce normal and tangential grinding forces by up to 56.3 % and 47.7 %, respectively, when compared to TGW. Furthermore, FLSGW has a higher workpiece surface quality than TGW and VSSGW. The FLSGW has significantly less abrasive wear than the of VSSGW and TGW.

Tangential dressing of diamond grinding wheel by femto-second pulsed laser with Bessel beam

Bronze bonded diamond grinding wheel is widely used in grinding hard and brittle materials. In order to improve the profile accuracy of the grinding wheel, an ultra-fast laser dressing method with Bessel beam for diamond grinding wheel is proposed in this study. The coarse grain (100 #) bronze bonded diamond grinding wheel is tangentially shaped by laser dressing. By comparing the profile and surface quality of the grinding wheel dressed with Gaussian laser beam and Bessel laser beam under different defocusing amounts, it is found that Bessel beam can dress the grinding wheel in the focal depth of 1.2 mm, which is three times of traditional Gaussian beam. The ablation thresholds of bronze binder and diamond under Bessel beam are obtained through experiments and theoretical calculations. The results show that when the laser power density is 3.75 × 105 W/cm2 – 4.75 × 105 W/cm2 and the axial scanning speed of the laser is 0.03 mm/min, the diamond grit has an enough protrusion height, and the runout of the grinding wheel is reduced to about 6 μm. When the wheel speed is too low, it will reduce the overlap rate of axial scanning trajectory and reduce the removal efficiency of material.

Research on laser preparation and grinding performance of hydrophilic structured grinding wheels

In order to solve the problems of workpiece damage and grinding wheel clogging when grinding difficult-to-cut materials such as alumina ceramics, organisms with regular hexagonal structures distributed on the body surface and with strong hydrophilicity and high anti-wear functions were used as biomimetic objects for the first time, and the preparation process optimization, structure size design and grinding performance evaluation of hydrophilic structured bronze-bonded diamond grinding wheels were explored in this paper. The influence of the preparation process parameters on the micro-topography and the dimensional accuracy of the structure on the surface of the grinding wheel was revealed, and a new laser structuring process based on the coordinated control of focus position and scanning times was proposed, which could efficiently prepare regular hexagonal structures with a small wall inclination angle and a depth of several millimeters on the surface of the grinding wheel. It was the first to clarify the influence of sub-millimeter-scale structure size on the contact angle of grinding fluid droplet on the surface of the grinding wheel and the surface hydrophilicity of the grinding wheel. Compared with that of the non-structured grinding wheel, the hydrophilicity of the structured grinding wheel was significantly improved, and its surface hydrophilicity increased with the increase of the structure spacing and depth, but had little correlation with the structure side length. The grinding performance of hydrophilic structured grinding wheels and non-structured grinding wheels was evaluated under extreme working conditions. Under the condition of grinding depth of 50 μm, 100 μm and 200 μm, compared with that of the non-structured grinding wheel, the peak grinding temperature of the structured grinding wheel was reduced by 18.0%, 30.4% and 15.2%, respectively, and the surface damage depth of the alumina ceramic after grinding by the structured grinding wheel was reduced by 53.7%, 46.8% and 24.3%, respectively. The hydrophilic structured grinding wheel can enhance the storage and transportation capacity of grinding fluid/chips, effectively relieve the clogging and dullness of the grinding wheel, and significantly reduce the high temperature and damage of grinding. In the next step, we will try to apply this type of grinding wheel to form grinding, in order to provide a reliable solution for suppressing form grinding damage of difficult-to-cut materials.

Experimental study on dressing concave trapezoidal diamond grinding wheel by electrical discharge grinding method

Electrical discharge grinding (EDG) method is proposed for dressing bronze bonded diamond grinding wheel for the first time. The advantage of this dressing method is that it can realize the discharge removal of non-conductive diamond abrasive particles and greatly improve the dressing efficiency. It is suitable for dressing coarse-grained complex forming grinding wheel. The material removal mechanism in EDG dressing is deeply analyzed, and a three-dimensional heat conduction model in the discharge process is established. The temperature field distribution in bronze and diamond under corresponding discharge parameters is obtained by numerical simulation, and the grinding depth is optimized based on the softening depth of diamond. The dressing scheme of quickly removing the rectangular block area first and then approaching layer by layer according to the design profile is formulated. The high-precision concave isosceles trapezoidal grinding wheel is dressed by using the optimized machining parameters. Finally, the dressing accuracy is evaluated by grinding the graphite plate. The detection results show that the dimensional errors of the upper and lower lines are all within 5 μm, the dimensional error of the height is 9 μm. The maximum error of the angle between the two waist is 0.33°. The minimum transition arc radius between waist and lower line is 202 μm. The straightness errors of the lower line and the two waist oblique lines are less than 7 μm. The profile error at the transition between waist and lower line is less than 62 μm.

Laser machining and compensation truing of small concave-arc bronze-bonded diamond grinding wheels

A laser can be effectively used as a “dressing pen” to dress super-abrasive forming grinding wheels. However, laser truing and sharpening methods are in their primary stages. Problems caused by poor dressing persist in the absence of a theoretical analysis of trimming, and there is no effective compensation algorithm to correct actual and theoretical deviations. A pulsed fibre laser was used to dress a small concave arc-profiled 230# bronze-bonded diamond grinding wheel in this study. The Canny-based sub-pixel edge detection algorithm was improved to effectively enhance the detection of circular edges. Experiments were performed on coarse laser dressing of profiling concave-arc wheels, and the regularity of the radius, angle and depth of the arc was investigated. An error analysis model for the laser profiling of small concave-arc grinding wheels was developed and used to determine the factors causing error and that the concave-arc grinding wheel produces a minimum roundness error of 34 μm under the considered experimental dressing conditions. A novel error compensation method for trimming was developed, the horizontal approximation compensation method (HACM). Compensated trimming experiments were performed with effective error compensation. The final trimming dimensional error was approximately 11.2 μm, and the roundness error was approximately 22.8 μm. The main external factors causing these errors were laser thermal effects and the burrs detected on the graphite plate.

Experimental study on laser dressing of bronze-bonded diamond arc grinding wheel based on self-powered sensor

Bronze bond diamond arc grinding wheel is used for ultra-precision grinding of complex surface brittle and hard materials, but its dressing and measurement are very difficult; for 230 # bronze bonded diamond grinding wheels, experimental studies on nanosecond laser truing, picosecond laser sharpening and grinding wheel surface accuracy measurement are conducted respectively. Surface topography detection, contour detection, and grinding performance experiments on the dressed grinding wheel are performed using a self-powered sensor and a super-depth of field three-dimensional microscope. The experiment results show that the average radius difference of the grinding wheel arc after fiber laser tangential truing is 4961 μm, with an error of 1.08% from the ideal radius of 5000 μm, and the deviation of the grinding wheel arc profile is 12.7 μm.After picosecond laser sharpening, the surface of the grinding wheel is obvious, the number of abrasive grains is high and dense, the diamond abrasive grains are well-preserved, 85% of the height of the abrasive grains protruding is in the qualified range, in line with the diamond arc grinding wheel sharpening requirements.The surface roughness of the machined alumina ceramic specimens could reach Ra1.28 μm at a grinding depth of 750 μm, meeting the machining requirements for semi-precision grinding of alumina ceramics.

Understanding the properties of bronze-bonded diamond grinding wheels on process behaviour

The process behaviour of bronze-bonded diamond grinding wheels depends on the selected bond composition and the sintering parameters. Understanding these dependencies is the key to a knowledge-based manufacturing process for grinding wheels. In this study, the wear behaviour of different bond compositions and sintering parameters is investigated. It could be shown that the predominant wear mechanism is mainly grain flattening and that it depends on the critical bond strength. Finally, these findings were used to analyse the workpiece quality in dependence of the variously manufactured grinding wheels. This enables a new approach for the production of load adapted grinding wheels.

Optimization of efficiency and uniformity of bond removal during laser sharpening

In order to improve the efficiency and uniformity of bond removal, a finite element model of multi-pulse laser ablation was established, and process experiments of laser ablation and sharpening were carried out in this paper. The results show that the efficiency of bond removal increased linearly with the increase of laser power density. Increasing the spot overlap ratio could improve the efficiency of bond removal, and changing the line overlap ratio had almost no effect on the efficiency of bond removal. Increasing the spot overlap ratio and the line overlap ratio was beneficial to improve the uniformity of the bond removal and ensure the uniformity of the grain protrusion height. The established finite element model could provide theoretical basis and data reference for determining the process parameter window and predicting the surface topography when performing the laser sharpening of grinding wheel (not limited to the bronze-bonded diamond grinding wheel), thereby saving cost and improving efficiency.

Theory and numerical model of the properties of plasma plume isothermal expansion during nanosecond laser ablation of a bronze-bonded diamond grinding wheel

Plasma expansion is anisotropic, which necessitates new plasma expansion kinetic models to precisely describe the evolution of the processes. The physical properties of the plasma during isothermal expansion during the nanosecond laser ablation of a bronze-bonded diamond grinding wheel were demonstrated in this work. Based on the regularities of the physical distribution, three-dimensional plasma equations were established, and the equations were applied to a numerical analysis of the ablation processes. Measurements using a grating spectrometer were carried out to detect the emission spectrum of the nanosecond laser ablation of a bronze-bonded diamond grinding wheel. The splash phenomena in the laser ablation process were observed with a high-speed camera. The expansion pressure of the plasma involved was low. According to the Boltzmann plot method and the Stark broadening method, the electron temperature was calculated to be 7206 K, and the electron density ranged from 5 × 1015 to 8 × 1015 cm−3. The experimental results and numerical simulation were consistent. The distribution of the plasma expansion processes presented in this work can contribute to the investigation of plasma characteristics in future research.

Expansion property of plasma plume for laser ablation of materials

We analysed the plasma expansion characteristics during a laser ablation process and derived dynamics equations to describe the plasma expansion. The equations include the plasma concentration spatial distribution equation, plasma expansion pressure equation and plasma dynamics equation for both the isothermal expansion stage and adiabatic expansion stage. The equations are reasonable, and the required parameters are related only to the laser parameters and materials properties, imparting the model with high versatility and practicability. The models were applied to a numerical simulation of plasma expansion characteristics in the laser ablation of a bronze-bonded diamond grinding wheel. The dimension of plasma isothermal expansion and plasma adiabatic expansion, the expansion velocity of the isothermal plasma, and the contour evolution of plasma expansion were determined. Experiments were then conducted with a high-speed camera to observe the same plasma expansion process for ablating the grinding wheel. A grating spectrometer was used to measure the emission spectrum during the laser ablation process, and the electron temperature and electron density were characterized. The results of the experiments and numerical simulation were found to be essentially consistent, verifying the accuracy and feasibility of the as-developed plasma dynamics equations, with positive implications for optimizing the laser ablation process.

A novel technique for dressing metal-bonded diamond grinding wheel with abrasive waterjet and touch truing

The dressing of metal-bonded diamond grinding wheels is difficult despite their availabilities on hard and brittle materials. In this paper, a novel compound technology that combines abrasive waterjet (AWJ) and touch truing is proposed for dressing metal-bonded diamond grinding wheel precisely and efficiently. The dressing experiments of a coarse-grained and a fine-grained bronze-bonded diamond grinding wheel were carried out on a surface grinder with a developed AWJ system. The feasibility of this method was verified by analyzing the wheel runout, the truing forces, and the wheel surface topography. The variations of 3D surface roughness of wheel surface topography during the compound dressing process were quantitatively analyzed. The mechanism of AWJ and touch compound dressing is also discussed. Further, a reaction-bonded silicon carbide block was ground to validate the dressing quality. The experiment results indicate that the grinding wheels that were well dressed by the proposed technique leads to a smaller grinding force and a smaller surface roughness than that of undressed wheels.

Research and application of plasma recoil pressure physical model for pulsed laser ablation material

In this paper, the physical properties of plasma in the isothermal expansion process when material is ablated by pulsed laser is analyzed. It is shown that the recoil pressure distribution of the plasma near the material surface indicates an exponential decrease as the distance from the material surface increases and the recoil pressure distribution exhibits the characteristics of a Poisson distribution in the X direction; the recoil pressure distribution is in accordance with Maxwell's velocity distribution law in the Y direction; the recoil pressure distribution conforms to a Gaussian distribution in the Z direction. A three-dimensional plasma recoil pressure equation and the plasma kinetic equation for laser-ablation materials are studied. These equations only require parameters to relate to plasma temperature, laser parameters and material properties, thus having a certain diversity. The equations are used for numerically analyzing the pulsed laser ablation of a bronze-bonded diamond grinding wheel. The numerical analysis shows that in the X and Y direction the plasma expansion dimension shows linear growth. After the pulse is ended, the plasma expansion dimension values reach their maxima. The plasma expansion velocity shows nonlinear growth. After the pulse is ended, the expansion velocity first increases and then decreases along the X direction and Y direction. Based on the analyses of the plasma expansion dimension and the plasma expansion velocity, the maximum plasma recoil pressure appears at a location approximately 0.05 mm away from the surface of the grinding wheel after approximately 25 ns. Through calculating the Saha equation, the degree of ionization is 0.0012 at 7506 K, and the maximum plasma recoil pressure value is approximately 870 Pa. The experiments on the pulsed laser ablation of a bronze-bonded diamond grinding wheel under the corresponding conditions are conducted. A high-speed camera is used to observe splash phenomenon in the laser ablation process. A grating spectrometer is used to measure the plasma emission spectrum. According to the Boltzmann plot method, the electron temperature value is calculated to be 7506 K; according to the Stark broadening method, the electron density values range from 7.6451015 to 1.16081016 cm-3 and the recoil pressure values from 792 to 1203 Pa. The experiments show that the recoil pressure during the pulsed laser ablation of bronze-bonded diamond grinding wheel process can be ignored, and the correctness and feasibility of the plasma recoil pressure equation are also verified, which has heuristic significance for optimizing the laser ablation process.

多脉冲激光修整青铜金刚石砂轮的表面变质层

多脉冲激光修整青铜金刚石砂轮的表面变质层

Pulsed Laser Profiling of Grinding Wheels at Normal and Quasi-Tangential Incidence

A new methodology for normal and quasi-tangential pulsed laser profiling of grinding wheels is proposed, with laser path planning calculated according to a pre-specified angle of incidence and radial laser progression or predicted single-pass incision depth. Though tangential laser profiling has previously been investigated, few works have addressed the issue of negligible laser absorption under these conditions other than to apply a focal offset that effectively reduces the angle of incidence below 90∘. In the present work, the angle of incidence is specified explicitly, with normal and quasi-tangential profiling experiments performed on rotating bronze-bonded diamond and porous aluminum oxide grinding wheels with a 1064 nm nanosecond pulsed fiber laser source with 20 W average power. Triangular incisions are cut into each sample, following which analyses are performed with an optical profiler operating in confocal mode and x-ray computed tomography to determine the material removal rate and profile accuracy under all tested conditions. The angle of laser incidence is found to be of particular relevance to profiling operations, with more than one order of magnitude difference in material removal rates observed between 70∘ and 80∘ incidence, with improved profile accuracy in the latter case. Specifically, material removal rates of 0.12−0.14 mm 3/s, 0.075−0.1 mm 3/s and 0.002 mm 3/s are achieved at normal, 70∘ and 80∘ laser incidence, respectively, for bronze-bonded diamond, and 0.1 mm 3/s is achieved at 70∘ incidence for porous aluminum oxide. For both materials, profile accuracy of 50−70 μm is achieved under optimum conditions. The presented results highlight the necessity for precise specification and control of the angle of incidence during laser profiling operations. They furthermore confirm that laser profiling of grinding wheels is a viable alternative to electrical discharge machining for bronze-bonded diamond grinding wheels and a potential complementary process to hard-on-hard abrasion for ceramics.

The grinding performance of a laser-dressed bronze-bonded diamond grinding wheel

Coarse-grained bronze-bonded diamond grinding wheels dressed using lasers and silicon carbide dressing wheels were used to grind YG8-cemented carbide workpieces. The wear patterns and grinding ratios of the laser-dressed grinding wheels were investigated after different grinding stages. After grinding, the laser-dressed grinding wheel displayed superior surface topography compared to the silicon carbide wheel, and the surface quality of the workpiece also improved. The minimum surface roughness of the workpiece was 0.425 μm. In the initial wear regime, the primary mechanisms included abrasive wear and grain removal. The grinding ratio was approximately 205.4, and the surface roughness of the workpiece after grinding was 0.314 μm. In the steady-state wear regime, abrasive wear was the primary mechanism of wearing, while minor amounts of grain removal and bond wear were observed. The grinding ratio was approximately 405.1, and the surface roughness was 0.337 μm. In the accelerated wear regime, the primary mechanisms were grain removal, abrasive wear, and bond wear. The grinding ratio was approximately 96.0, and the surface roughness was 0.454 μm.

Study on methods to optimize laser-sharpening quality, efficiency and topography

This paper aims to improve bond surface smoothness, sharpening quality and efficiency as well as control grain protrusion height. Systematic research was performed on pulsed fiber laser sharpening of a coarse-grained bronze-bonded diamond grinding wheel. The results show that bond surface smoothness is related to the laser spot overlap ratio Uc and the laser scan track overlap ratio Ul. In the range 10–70%, an increase in Uc and Ul improved the sharpened bond surface smoothness. Sharpening quality and efficiency are both related to laser power density Ip. In the range 2.115–6.344×107Wcm−2, an increase in Ip gradually improved sharpening efficiency, but the sharpening quality trend initially improved followed by a subsequent decline. The grain protrusion height is related to the laser scan cycles N. An excessively small N will result in an insufficient chip space such that the grinding wheel is likely blocked. Grains will likely fall off due to an insufficient holding force if N is excessively large. Compared with silicon carbide grinding wheel sharpening, a pulsed laser-sharpened grinding wheel exhibits less surface grain fall-off, better grain height uniformity, more chip space around the grain and superior grinding wheel surface topography.

Online, efficient and precision laser profiling of bronze-bonded diamond grinding wheels based on a single-layer deep-cutting intermittent feeding method

In this study, an online, efficient and precision laser profiling approach that is based on a single-layer deep-cutting intermittent feeding method is described. The effects of the laser cutting depth and the track-overlap ratio of the laser cutting on the efficiency, precision and quality of laser profiling were investigated. Experiments on the online profiling of bronze-bonded diamond grinding wheels were performed using a pulsed fiber laser. The results demonstrate that an increase in the laser cutting depth caused an increase in the material removal efficiency during the laser profiling process. However, the maximum laser profiling efficiency was only achieved when the laser cutting depth was equivalent to the initial surface contour error of the grinding wheel. In addition, the selection of relatively high track-overlap ratios of laser cutting for the profiling of grinding wheels was beneficial with respect to the increase in the precision of laser profiling, whereas the efficiency and quality of the laser profiling were not affected by the change in the track-overlap ratio. After optimized process parameters were employed for online laser profiling, the circular run-out error and the parallelism error of the grinding wheel surface decreased from 83.1μm and 324.6μm to 11.3μm and 3.5μm, respectively. The surface contour precision of the grinding wheel significantly improved. The highest surface contour precision for grinding wheels of the same type that can be theoretically achieved after laser profiling is completely dependent on the peak power density of the laser. The higher the laser peak power density is, the higher the surface contour precision of the grinding wheel after profiling.

Study of the grinding performance of laser-trued and dressed bronzed-bonded diamond grinding wheels

A triangulation-based closed-loop control system with high-precision couple charged device (CCD) laser displacement sensors was used to true and dress a bronze-bonded diamond grinding wheel online with an acousto-optic Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser. The microscopic surface topography of the trued and dressed grinding wheel was observed using a three-dimensional (3D) microscope with an ultra-large depth of field. The results showed that the diamond abrasives were uniformly distributed on and protruded from the surface of the bronze bond, which indicated good topography of the grinding wheel. Orthogonal grinding experiments were conducted on the laser-dressed bronze-bonded diamond wheel, and three quality evaluation indices, the grinding ratio, the grinding force ratio, and the workpiece surface roughness, were measured and calculated. The results of the grinding experiment were systematically analyzed using a gray relational analysis. Under the experimental conditions of this study, the dominant factor that affected the quality evaluation indices was the laser spot diameter, followed by the pulse duration. The laser power was a secondary factor.

On the laser-driven integrated dressing and truing of bronze-bonded grinding wheels

This paper analysed the physical process of multipulse laser ablation of a bronze–diamond grinding wheel. The analysis considered the effects of phase explosion, plasma shielding effects and energy accumulation under the pulse interval, and it includes heat transfer equations for multipulse laser ablation of the bronze-bonded diamond grinding wheel. The model was applied for numerical simulation of the heat transfer characteristics in the multipulse laser ablation of bronze and diamond. Next, experiments were conducted to analyse the topography of a bronze-bonded diamond grinding wheel after multipulse laser ablation. The theoretical analysis and experimental results showed that a multipulse laser can merge the truing and dressing on a bronze-bonded diamond grinding wheel. A comparative analysis showed that the numerical solution to the model is in good agreement with the experimental data. This study provides theoretical guidance for optimising the process parameters in the laser ablation of a bronze-bonded diamond grinding wheel.