Electroplated Grinding Wheel Research Articles

Development of a novel bulk metallic glass bonded single-layer diamond wheel

A novel manufacturing process was employed to develop a single-layer diamond wheel using bulk metallic glass (BMG) as the matrix and diamond particles as abrasives. BMG effectively prevented graphitisation and damage to the diamond abrasives because of its lower manufacturing temperature and avoidance of brazing flux. The Titanium (Ti) coating on the surface of diamond abrasives facilitated the formation of an interleaved dissolution-diffusion interface between the two constituents, creating mechanical occlusion at the BMG-diamond interface. The strong and tight bonding interface afforded a diamond abrasive joint strength of up to 112.59 N, with the main shear failure mode being transgranular fracture instead of pull-off failure. Furthermore, the manufactured BMG-bonded single-layer diamond wheel predominantly exhibited attritious wear instead of the exfoliation of abrasives when grinding Al2O3 ceramics. Compared with contemporary electroplated grinding wheels, the developed diamond wheel demonstrated a reduction in the normal and tangential grinding forces of 32.64% and 35.86%, respectively, and a 28.22% increase in the grinding ratio, making it an excellent candidate for grinding hard and brittle materials.

Experimental study on grinding 2.5D C/SiC composites by electroplated grinding wheel with ordered abrasive clusters

To alleviate the problems of poor machining quality, short tool life, and low machining efficiency in the machining of 2.5D needled C/SiC composites, the bionic idea was adopted in this research, the heat dissipation performance of the windmill and the hydrophobic heat dissipation performance of the sunflower seeds were used to design two types of abrasive clusters ordered grinding wheels. The motion trajectory equation of single abrasive in the abrasive cluster of the grinding wheel end face was established, and the superposition motion trajectory of numerous abrasives in the abrasive clusters ordered grinding wheel was simulated. Through the grinding experiment of 2.5D needled C/SiC composites, the effects of ordered grinding wheels on surface roughness, microstructure, grinding force, grinding temperature and wear condition were investigated. The results demonstrated that the simulation results are compatible with the grinding marks left by the two types of ordered grinding wheels. Surface roughness, grinding force, and temperature all were improved to a considerable extent with both types of ordered grinding wheels. Compared to the disordered grinding wheel, type A and type B ordered grinding wheels can decrease the surface roughness of the C/SiC composite groove's bottom surface by 40.7 % and 35.8 % respectively. Additionally, they can reduce the grinding force Fy by up to 68.3 % and 53.2 % respectively, and the grinding force Fz by up to 70.4 % and 46.9 % respectively.

Prediction of Grinding Force by an Electroplated Grinding Wheel with Orderly-Micro-Grooves

The ability to predict a grinding force is important to control, monitor, and optimize the grinding process. Few theoretical models were developed to predict grinding forces when a structured wheel was used in a grinding process. This paper aimed to establish a single-grit cutting force model to predict the ploughing, friction and cutting forces in a grinding process. It took into the consideration of actual topography of the grinding wheel, and a theoretical grinding force model for grinding hardened AISI 52100 by the wheel with orderly-micro-grooves was proposed. The model was innovative in the sense that it represented the random thickness of undeformed chips by a probabilistic expression, and it reflected the microstructure characteristics of the structured wheel explicitly. Note that the microstructure depended on the randomness of the protruding heights and distribution density of the grits over the wheel. The proposed force prediction model was validated by surface grinding experiments, and the results showed (1) a good agreement of the predicted and measured forces and (2) a good agreement of the changes of the grinding forces along with the changes of grinding parameters in the prediction model and experiments. This research proposed a theoretical grinding force model of an electroplated grinding wheel with orderly-micro-grooves which is accurate, reliable and effective in predicting grinding forces.

Experimental research on wear mechanism of diamond wheels for grinding Cf/SiC composites grooves

Aiming at the problems of low processing efficiency, low groove shape accuracy and poor surface quality caused by grinding wheel wear in the grinding process of Cf/SiC composite grooves. In this paper, based on the motion mode of grinding wheel grinding, the wear volume formula of grinding wheels was analyzed, and the grinding wheel wear comparison experiment of different bond diamond grinding wheels grinding Cf/SiC composite grooves was carried out, and the more suitable kind of diamond grinding wheel for grinding Cf/SiC composite grooves was selected. From the experimental results, compared with the ceramic-bonded diamond wheel and resin-bonded diamond wheel, the grinding times of electroplated diamond wheel grinding Cf/SiC composites were increased by 20 and 104, respectively, and the surface roughness of the groove was most stable and the processing damage was smallest. Therefore, the best quality of grinding Cf/SiC composites groove was obtained by the electroplated diamond grinding wheel, and its life in grinding Cf/SiC composites was the longest. At the same time, the wear mechanism of the electroplated grinding wheel was explored, the wear on the bottom surface of the electroplated grinding wheel was more serious than that on the circumferential surface. The wear on the bottom surface was mainly wear and tear, and it gradually diffused along the inner diameter of the grinding wheel with the increasing grinding times.

Simulation and experiment of electroplated grinding wheel with orderly-micro-grooves

The coolant is difficult to enter the grinding zone for effective lubrication by using traditional grinding wheel. Therefore, how to improve the performance of grinding wheel by changing the structure of working face is always a concern. In order to facilitate lubrication and improve cooling performance during grinding, an electroplated grinding wheel is prepared to has a set of orderly-micro-grooves with 0.1 mm in width, 1.5 mm in depth and 0.98 mm in interval on its peripheral surface. The simulation model of the proposed grinding wheel is developed to analyze the flow field of coolant. It is found that (1) the micro-grooves on wheel provide new channels for more coolant to flow into the grinding zone, (2) the volume of useful coolant is increased with a decrease of the width of micro-grooves, and (3) micro-grooves provide additional space to store and transport chips produced in the grinding zone, which alleviates the clogging of the grinding wheel. In order to investigate the impact of micro-grooves on the grinding forces, the grains are modelled as being randomly distributed and oriented on the grinding wheel, and the grinding processes are simulated for both of micro-grooved and un-grooved wheels. The comparative simulation shows that the orderly-micro-grooves reduce both of the normal and tangential grinding forces. Moreover, the fluctuating amplitude of the grinding force is decreased with a decrease of the width of micro-grooves. The simulation results are validated by the grinding experiment on silica glass, and the experiments also show that the orderly-micro-grooves reduce the grinding temperature.

Process limits in high-performance peel grinding of hardened steel components with coarse CBN grinding wheels

Recent developments in the production processes for cubic boron nitride (CBN) abrasive grains have led to commercially available grain sizes larger than lg > 300 µm. These superabrasive grains allow higher material removal rates during grinding of hardened steel components. Currently, these components are pre-machined by turning processes before being hardened and eventually finished by grinding. However, the turning process can be substituted by grinding with coarse CBN-grains since higher depths of cut are achievable when machining hardened components. This paper investigates the process behaviour of vitrified and electroplated grinding wheels with large grain sizes during the machining of hardened steel components. Process forces, wear behaviour and workpiece surface roughness are investigated for three different grain sizes, and the process limits of both bond types are examined. The investigations show that vitrified tools do not fully suit the demands for peel grinding process with high material removal rates since wear by bond breakage occurs. The electroplated tools on the other hand are capable of very high material removal rates. Their wear behaviour is characterized by clogging of the chip space if the process limit is reached. Even so, both tools outperform a standard hard-turning process in terms of process time by 74% and 94% respectively. This process time reduction in combination with the possibility to use the same (machine) tool to machine both soft and hard sections of a workpiece adds flexibility to current process chains.

Design of a defined grain distribution brazed diamond grinding wheel for ultrasonic assisted grinding and experimental verification

Ultrasonic assisted grinding (UAG) is a promising manufacturing technology in processing hard and brittle materials, mostly due to its excellent machining performance. In UAG, improvements in grain trajectory interactions and overlapping stemming from kinematic characteristics were identified as the main reasons for reduced grinding forces and improved processing quality. However, in existing studies, the grinding wheels with disordered abrasive grain distributions and irregular grain protrusion heights were generally used. Consequently, it is difficult to control both the interactions between grain trajectories and overlapping. Aiming to solve this problem, a brazed diamond grinding wheel with defined grain distribution was proposed in this study. The grinding wheel matrix was designed using finite element analysis, while abrasive grain distribution was obtained by kinematic analysis of UAG. Finally, the grinding wheel was prepared using brazing technology and to verify its grinding performance, an electroplated grinding wheel with the identic matrix and abrasive grain size was prepared. Morphology analysis of both grinding wheels has shown that compared to the electroplated grinding wheel, the brazed one has both higher and more uniform grain protrusion height. In the next step, UAG and CG experiments were carried out using the brazed and electroplated grinding wheel. The effects of grain distribution and grinding parameters on the grinding force, force ratio, surface profile wave, and surface roughness were studied. The results have shown that in similar operating conditions the brazed grinding wheel produced smaller grinding force, force ratio, smoother ground surface, and lower surface roughness compared to the electroplated grinding wheel. Additionally, for both grinding wheels, the UAG reduced grinding force, force ratio, surface roughness, and profile wave height. However, it also caused a more extensive ultrasonic vibration effect on grinding compared to the electroplated grinding wheel; its reduction percentage in grinding force was larger, while surface roughness and average height difference for UAG were higher compared to CG.

Creep-Feed Grinding Wheel Development for Safely Grinding Aerospace Alloys

Creep-feed grinding wheels have been associated with advances in processing difficult-to-cut materials used in the aerospace industry for many years. Since the late 1960s, the development of grinding wheels used for creep-feed grinding (CFG) operations and high-efficiency deep grinding (HEDG) operations has placed great responsibility on grinding wheel manufacturers to produce bonding systems of high strength and bonding bridges with smaller cross-sectional area. The safety of grinding wheels has become very important in recent years due to the increases in porosity (~ 50% vol.) and reductions in bond content (~ 5% vol.). This has necessitated the development of very strong bonding systems that can withstand high rotational, thermal, clamping and contact stresses. The paper not only provides a review of work performed on conventional grinding wheels, but also explains how the use of computational modeling techniques are used to simulate the stresses experienced by superabrasive wheels that are used at high-speeds in creep-feed grinding (CFG), high-efficiency deep grinding (HEDG) and peel grinding (PG) processes. Superabrasive materials of choice for use on difficult-to-machine alloys are typically cubic boron nitride (cBN) and diamond bonded with a vitrified glass-ceramic bonding system. The current work also explains how Weibull statistics are used to characterize the strength of the abrasive-porosity-bond composite structure and how the computational and Weibull statistical analyses are unified through the use of a simple measure of operational integrity known as the safety factor. The paper concludes by showing the reader how computational techniques can be used to design CFG wheels by optimizing abrasive segments bonded to a reinforcing material of high strength operating at a specific peripheral speed. It should be noted that this study is applicable to multi-layered CFG wheels and not to single-layer electroplated grinding wheels that are also used in CFG operations.

Effect of laser-discrete-quenching on bonding properties of electroplated grinding wheel with AISI 1045 steel substrate and nickel bond

To improve the bonding strength between the nickel bond and the hub of the electroplated diamond grinding wheel, a hybrid technique was proposed to combine laser pre-quenching steel substrate and post-electroplating nickel. To validate the effectiveness of the proposed technique, AISI 1045 substrate was nickel-coated. The bonding properties between the electroplated nickel coating and substrate with or without laser-discrete-quenching were discussed comparatively by scratch, indentation, and thermal shock tests. The results show that the pre-quenching treatment leads to phase transformation of AISI 1045 microstructure from the mixed pearlite and ferrite phases into the martensitic phase. Since the martensitic phase is characterized as a high corrosion resistance, the interface of substrate/coating is smooth and flat in the pre-quenched zone, and the coating is bonded well with the steel substrate. In contrast to the steel substrate without pre-quenching treatment, the proposed technique significantly enhanced the bonding strengths of the electroplated nickel-coating. On one hand, the average hardness of electroplated nickel-coating on the laser pre-quenched zone is increased by 18.7%, and the scratch depth with the same load become narrower and shallower. On the other hand, the coefficient of friction (CoF) and the vibration amplitude are reduced, and the coating is bonded effectively with the substrate to inhibit the crack initialization at the interface. This prevents effectively the coating from peeling off and improves significantly the thermal shock resistance property.

Study on textured CBN grinding wheel by laser cladding

In this investigation, in order to improve bonding strength between superabrasive/metal matrix/grinding substrate, life span of grinding wheel, and grinding using small grits in continuous grinding simultaneously to fit for high speed and high precision machining in industry, coaxial powder feeding laser cladding method with CAD/CAM technology is introduced to manufacture textured CBN/CuSnTi–grinding wheels. The morphology of CBN grit on laser-cladding layer under optimized laser-cladding parameters and a pit created by fallen-off CBN on laser-cladding layer with lower laser–cladding energy density are observed by scanning electron microscope (SEM). The element distributions of interfaces of CBN/CuSnTi/AISI 1045 are analyzed by SEM and energy disperse spectroscope (EDS). The morphology and elements distribution of residual resultants on the surface of CBN grits etched by nitric acid are analyzed by SEM and EDS. Comparative-grinding process between laser cladding–grinding wheel (LCGW) and customized electroplated grinding wheel (EGW) is analyzed with grinding forces and temperature aspects respectively. The wear morphology of CBN grits on LCGW after grinding is observed by SEM. The results show that CBN grit with integrate cutting edges can protrude 50% height of its diameter on laser-cladding layer under optimized laser–cladding parameters. Fe, N, Ti, and B segregates attached to the interfaces of CBN/CuSnTi/AISI 1045 with Cu and Sn distributed uniformly in the laser-cladding layer. Residual resultants on CBN can be divided into two parts based on the distances from the surface of CBN grits. The grinding forces (Fz and Fy) and grinding temperature from LCGW are lower than those from EGW. The wear conditions of CBN on laser cladding are three parts: microfracture, cleavage plane, and wear-out.

A Calculation Method for Dressing Amount of Monolayer Electroplated Grinding Wheel Based on Zernike Moment

Aiming at the difficulties in accurate prediction of the dressing amount of monolayer electroplated grinding wheel, a new calculation method based on image processing was proposed. For the purpose of increasing the measurement precision, all images were captured by CCD camera and a sub-pixel level accuracy edge detection approach based on Zernike moment was used. Two dressing amount of electroplated grinding wheel were calculated by protrusion height and run-out respectively, and the larger number of them was chosen as the optimal dressing amount. Finally, this method is applied to calculate the optimal dressing amount of 30 gothic-arc profile electroplated grinding wheels, and they were dressed by optical contour grinder. The results showed that, form precision of grinding wheels and roughness of workpiece were fine.

Three-dimensional characterization and modeling of diamond electroplated grinding wheels

This paper presents a study on the three-dimensional characterization and modeling of morphology of diamond abrasive grains and electroplated diamond grinding wheels. A diamond abrasive grain was modeled by a cubo-octahedron that was determined by the intersection between an octahedron and a cube. The study revealed that the side length of octahedron and its side-length ratio followed a normal distribution and a generalized extreme value distribution, respectively. High-precision characterizations of grain density and protrusion height were realized by measuring wheel replicas with laser scanning confocal microscopy (LSCM). It was found that the grain protrusion height followed a normal distribution with an average of ∼40% of the grain size. Considering the randomly-distributed shape, size, position and protrusion height of abrasive grains, a geometric model of electroplated diamond wheels was established. The results show that the predicted morphology of grinding wheels agreed well with the experimentally measured. The model enables an accurate kinematic simulation for designing precision grinding processes.

Improved performance of electroplated grinding wheels using a new method of controlled grain size sorting

The protrusion heights of grains on electroplated grinding wheel are uneven. This phenomenon has a negative influence on the grinding performance of electroplated grinding wheel. In this paper, CBN and diamond grains were sorted by hydraulic power method. Four kinds of electroplated grinding wheels were fabricated with selected and unselected CBN diamond grains. Then, the surface roughness of workpieces ground by the four kinds of grinding wheels were investigated and analyzed in contrast experiments. The experimental results show that the grains sorting method using hydraulic power can homogenize the size of grains; and lower ground surface roughness has been obtained by the electroplated grinding wheels with the help of the new method of controlled grain size sorting.

Detailed Analysis and Description of Grinding Wheel Topographies

In this paper, an innovative approach for the description of the functional properties of a grinding wheel surface is discussed. First, the state of the art in the description of grinding wheel topographies is summarized. Furthermore, the fundamentals for a new approach for the quantitative description of grinding wheel topographies are provided. In order to analyze the functional properties of a grinding wheel's topography depending on its specification, grinding experiments were carried out. For the experimental investigations vitrified, synthetic resin bonded and electroplated grinding wheels with varied compositions were analyzed. During the experiments, the topographies of the investigated grinding wheels have been analyzed by means of the topotool in detail. The developed software tool allows a detailed description of the kinematic cutting edges depending on the grinding process parameters and the grinding wheel specification. In addition to the calculation of the number of kinematic cutting edges and the area per cutting edge, a differentiation of the cutting edge areas in normal and tangential areas of the grinding wheel's circumferential direction is implemented. Furthermore, the topotool enables to analyze the kinematic cutting edges shape by calculating the angles of the grain in different directions. This enables a detailed analysis and a quantitative comparison of grinding wheel topographies related to different grinding wheel specifications. In addition, the influence of the dressing process and wear conditions to the grinding wheel topography can be evaluated. The new approach allows a better characterization of the contact conditions between grinding wheel and workpiece. Hence, the impact of a specific topography on the grinding process behavior, the generated grinding energy distribution, and the grinding result can be revealed.

A novel ultrasonic-assisted dressing method of electroplated grinding wheels via stationary diamond dresser

To achieve fine surface roughness, tungsten carbides are mostly ground with resin or vitrified bonded diamond wheels. The use of cost-effective electroplated diamond tools (single layer) is, despite some specific improvements, such as geometrical flexibility, excellent profile holding, large chip spaces and good cooling characteristics, which allows even dry grinding processes, unusual when fine surface roughness is desired. It is generally due to the high grain protrusion (approx. 40 % compared to approx. 15 % with resin bonded or vitrified diamond wheels) which leads to the induced grooves on the ground surface combined with high surface roughness. Another disadvantage of single-layer bonded grinding wheels is their low range of dress ability. This article describes a possibility to overcome the drawbacks of the electroplated diamond wheels by ultrasonic-assisted fracturing of the diamond grains. For this purpose, an ultrasonic-assisted stationary dresser is used. The ultrasonic unit generates hits on the diamond grains. The grinding wheel rotates with a very slow circumferential speed, which is uncommon in conventional dressing methods, so that the grains are fractured by the oscillating movement of the dresser. However, numerous sharp cutting edges are generated due to the generated hits. This method allows the generation of cutting edges on relatively course grain sizes (in this case, D251) that have the properties of smaller grain sizes, and therefore, surfaces with lower roughness values are produced while the advantages of the electroplated grinding wheels, such as good profile keeping and good cooling characteristic, are maintained. Additionally, the service life of the electroplated wheel can be increased and the grinding parameters can be kept nearly constant. Experimental analyses have shown that the grinding of tungsten carbide with fractured electroplated D251 diamonds enables fine surface roughness from Ra < 0.1 μm and Rz < 0.8 μm.

Odwzorowanie zmian uproszczonego modelu geometrycznego CPS ściernicy z CBN w kontekście wybranych parametrów jej topografii

Odwzorowanie zmian uproszczonego modelu geometrycznego CPS ściernicy z CBN w kontekście wybranych parametrów jej topografii

The measurement and analysis of micro bonding force for electroplated CBN grinding wheels based on response surface methodology

The superabrasive (e.g. CBN or diamond) grain dislodgement occurrence on the wheel surface due to insufficient bonding force is the major failure phenomena in the grinding process with electroplated grinding tools. This failure leads to the abrupt increase of load on the immediate grains, accelerating more grain dislodgement on wheel surface. Ultimately, the aggregated grain dislodgement causes the workpiece profile accuracy degradation and catastrophic wheel sharpness loss. Therefore, the provision of sufficient and uniform micro bonding force all through the wheel surface is the critical task in electroplated superabrasive grinding wheel design. Considering the complexity in the micro bonding force enabling factors, e.g. the grain shape, dimensional size, spatial orientation, and bond layer thickness, it is vital to establish the quantitative and comprehensive relationship between these factors with the micro bonding force for optimal electroplated grinding wheel design. In this paper, an inclined micro-thread turning test is developed to measure the single grain micro bonding force. In addition, the finite element model of single CBN grain bonding force is established and validated to simulate the grain dislodgement. Finally, the response surface methodology (RSM) is applied to build the comprehensive correlation of the bonding force with its dimensional size, spatial orientation, and bond layer thickness. Therefore, the optimal bonding condition through regressed prediction model is identified to provide the quantitative basis for the electroplated CBN grinding wheels design, which indicates that the bonding force can be predicted for specific wheel manufacturing parameters and improved by related variable adjustment.

Ultrasonic Vibration Effect in Grinding of Ceramic (Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;)

In this work, machining test was carried out in various machining conditions using ultrasonical vibration capable CNC machine. For work material, alumina ceramic (Al2O3) was used while for tool material diamond electroplated grinding wheel was used. To evaluate ultrasonical vibration effect, grinding test was performed with and without ultrasonic vibration in same machining condition. In ultrasonic mode, ultrasonic vibration of 20kHz was generated by HSK 63 ultrasonic actuator. On the other hand, grinding forces were measured by KISTLER dynamometer. And an optimal sampling rate for grinding force measurement was obtained by a signal processing and frequency analysis. The surface roughness of the ceramic was also measured using stylus type surface roughness instrument and atomic force microscope (AFM). Besides, the scanning electron microscope (SEM) was used for observation of surface integrarity.

Understanding of Ultrasonic Assisted Machining with Diamond Grinding Tool

In this work, machining test was carried out in various machining conditions using ultrasonic vibration capable CNC machine. For work material, alumina ceramic (Al2O3) was used while for tool material diamond electroplated grinding wheel was used. To evaluate ultrasonic vibration effect, grinding test was performed with and without ultrasonic vibration in same machining condition. In ultrasonic mode, ultrasonic vibration of 20 kHz was generated by HSK 63 ultrasonic actuator. On the other hand, grinding forces were measured by KISTLER dynamometer. And an optimal sampling rate for grinding force measurement was obtained by a signal processing and frequency analysis. The surface roughness of the ceramic was also measured by using stylus type surface roughness instrument and atomic force microscope (AFM). Besides, the scanning electron microscope (SEM) was used for observation of surface integrality.

High Efficient Precision Conditioning of the Electroplated Diamond Wheel and Grinding of Fused Silica Glasses

Generally, the fine abrasive diamond wheel is used to the precision/ ultra-precision grinding of large-size optical glasses, but there're some disadvantages, such as the frequent wheel conditioning, uncontrollable surface accuracy, and low processing efficiency. Coarse abrasive diamond wheel can implement a higher surface accuracy machining with large grinding ratio. However, to achieve precision grinding, efficient precision conditioning is very critical. The electroplated diamond grinding wheel(grit-size 151 μm) is rough trued using the Cr12 steel. The gathering heat speeds up the diamond wear, so the run-out error of grinding wheel is quickly down to below 10 μm. Combined with electrolytic in-process dressing technique(ELID), cup-shaped diamond roller is applied to precision condition the electroplated grinding wheel. The wheel's run-out error drops to within 6 μm, and the axial gradient error is reduced from 6 μm to 2.5 μm. By the wheel wear morphology and the Raman spectral curve, the conditioning mechanism is analyzed. In different wheel truing stage, the fused silica is surface ground respectively. Using the high run-out error grinding wheel, the optical glass is mainly removed in the form of brittle fracture. When the run-out error and axial gradient error reduce, the fused silica glass is ground mainly as plastic removal, with the surface roughness Ra 19.6 nm and subsurface crack depth 2 μm. Thus, the well trued coarse abrasive grinding wheel can be considered for precision machining optical elements.