Brazed Diamond Grinding Wheel Research Articles

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.

Modeling and simulation of the distribution of undeformed chip thicknesses in surface grinding

Abstract The distribution of undeformed chip thicknesses is the kinematic “copy” of grain space distribution on a workpiece and has an important influence on the grinding results. In this study, a wheel topography model is developed that can be integrated with a workpiece model, a kinematic model and a calculation model of undeformed chip thickness of a single grain to obtain the distribution of undeformed chip thicknesses. In order to verify the integrated model, a single-layer brazed diamond grinding wheel is fabricated, and the topography measurements of the grinding wheel are conducted. The measured data are used in the integrated model to perform a simulation; the simulation results are consistent with the test results. At the same time, the model is verified with grains that are uniformly distributed. Then, simulations utilizing the integrated model are used to thoroughly study the grinding process. The distribution of grain protrusion height can be controlled by radial numerical dressings on the grinding wheel. Thus, the role of the distribution of grain protrusion height on the undeformed chip thickness distribution can be quantified by using radial numerical dressings on the grinding wheel. Additionally, the relationship between the average value of the distribution of undeformed chip thicknesses, hmean, and the surface roughness can be determined by simulation. It is shown that the surface roughness can be controlled quantitatively by radial numerical dressings on the wheel.

Study on the grain damage characteristics of brazed diamond grinding wheel using a laser in face grinding

This paper describes the grain damage characteristics of a grinding wheel with laser-brazing and discusses its relationship to the normal grinding force during the face grinding of granite. The results of our experiment show that the primary wears patterns of the brazed diamond grinding wheel in the whole grinding process are whole, wear-away, micro-fractured, and macro-fractured. There is no type of falling-off for the diamond grinding wheel, so the result indicates that it is possible to braze the diamond grits through appropriately manipulating the parameters of the laser. During the grinding process, the diamond shapes cause grinding forces to vary, and these variations actuate the transformation of the diamond shapes. The results obtained in this paper provide a reference for researching the wear mechanism of diamond grains, for optimizing grinding parameters, and for consummating the manufacture of laser brazed diamond tools.

Study on the Dullness of Monolayer Brazed Diamond Grinding Wheel through Plate Wheel Dressing

A monolayer brazed diamond grinding wheel was dressed 23 times with a plate wheel. The grinding forces were measured during the grinding experiments which carried out on SiC ceramics after each dressing interval. The surface roughness of SiC ceramics was also measured. In this study, the dullness of the grinding wheel during the dressing procedure is mainly discussed. The results showed that the surface roughness of SiC ceramics reduced a lot after dressing which means the dressed grinding wheel can meet the requirements of precision machining. On the premise of this, there was no obvious dullness occurred on the grits of the grinding wheel during dressing because new cutting edges had emerged.

Grinding of brittle materials with brazed diamond grinding wheel

Brazed diamond grinding tool is the most promising tool, which is fitter for powerful and high-efficiency grinding and may be the substitute of plated one in the future. But the research of the tool on brittle material grinding is still few. In the paper, it has been proved that the tool can achieve much better surface quality than any other tools, though large grit size is used in the tool fabrication. Analysis shows that most brittle material surface quality can be improved with the decrease of depth of cut of single grit, but they cannot be improved further because of some unavoidable surface defects.

Experimental Study on Performance of Monolayer Brazed Diamond Wheel through Chemical-Mechanical Dressing

The dressing methods of monolayer diamond tool have recently been developed increasingly because a substantial improvement of the ground surface roughness could be achieved with the dressed monolayer diamond tools. In this paper, a new dressing method was proposed, namely chemical-mechanical dressing of the diamond grits. Dressing experiments were carried out on the monolayer brazed diamond grinding wheel. The grit-tip distances from the base of wheel substrate were measured before and after dressing. Grinding experiments were conducted on K9 optical glass after each dressing interval. The roughness parameters of the ground surfaces were measured. The outcome of this attempt appeared highly encouraging, and the dressing of monolayer brazed diamond grinding wheel is effective with the chemical-mechanical dressing.

Performance of Laser Brazing Diamond Grinding Wheel in Face Grinding

A new technology kind of brazed monolayer cup diamond grinding wheel was developed via laser in an argon atmosphere. Grinding performances of this kind of brazed wheel in the surface grinding of the granites were studied. The experiment results show that the normal grinding forces and wear of diamond grits become higher with the increasing of the accumulated removal volume during grinding granites process. When continuous dry grinding was employed, the grits of the brazed diamond grinding wheel fail mainly in attired wear mode other than pull-out ones in conventional electroplated and sintered diamond tools, which indicates that the strong retention of brazing alloy to the diamond grits and longer service life of this kind of wheel.

Experiment Research on Grinding of Optical Glass with Indigenously Developed Monolayer Brazed Diamond Grinding Wheel

Conventional grinding of optical glass will normally result in not only much lower material removal rate but also short service life of grinding tools, which causes the high fabrication cost of optical glass. This paper focuses on the precision grinding of optical glass with the indigenously developed monolayer brazed diamond grinding wheel. Before grinding process a precision dressing is conduct. The dressed grinding wheel topography is observed. Through precision dressing the grinding process achieves moderate surface finish as well as ensures certain grinding efficiency. The ground surface of the optical glass workpiece is made up of micro-pits and glazing zones and the obtained surface roughness variation with the process parameters is analyzed. The experiment shows that the developed diamond grinding wheel is suitable to the application of optical glass machining.

Surface/Subsurface Damage of Yttria Partially Stabilized Zirconia in Grinding Using Monolayer Brazed Diamond Wheel

A new brazed monolayer diamond grinding wheel is developed with the same continuous cutting edge distance on the wheel surface. Surface/subsurface damage of yttria partially stabilized zirconia (Y-PSZ) in grinding using monolayer brazed diamond wheel is analyzed. In this investigation, the influence of the maximum undeformed chip thickness (hm) on material removal mechanism is analyzed. The experiment results show that the ground surface is almost in ductile material removal mode when hm is below the critical value for Y-PSZ, otherwise it will be the combined removal modes of brittle and ductile when hm is above the critical value.

Wear of a brazed diamond grinding wheel with diamonds precovered by brazing alloy

The wear of a brazed diamond wheel with diamond grits precovered by brazing alloy was investigated in comparison with a traditional brazed wheel whose grits were without coverings. The two wheels were brazed in vacuum. The wear of the two wheels was tested through grinding of granite, during which grinding forces were measured and the wear states of diamond grits were observed. It is shown that the brazed diamonds precovered with brazing alloy exhibited stronger self-sharpening ability and rupture resistance. Subsequently, the wheel with precovered diamonds performed lower grinding force and better wear performance.

The Effect of a Rotating Heat Pipe in a Brazed Diamond Grinding Wheel on Grinding Temperature

A new type of brazed diamond grinding wheel with a rotating heat pipe is developed to effectively remove the heat generated in the grinding zone meanwhile minimize the pollution and contamination of the environment. A grinding temperature-measurement experiment of titanium alloy was conducted to evaluate enhanced heat transfer effect of the rotating heat pipe on the grinding zone. The experiment results show that, when grinding using the wheel with heat pipe the grinding temperature decreases 30% than that using the wheel without heat pipe.

Wear of a Brazed Diamond Grinding Wheel with Diamond Grits Covered with Brazing Alloy

The wear of a brazed diamond wheel with diamond grits covered with brazing alloy was investigated in comparison with a traditional brazed wheel whose grits were without covering. The two wheels were brazed in vacuum furnace and grits on one of them were overlaid with a thin layer of brazing alloy. The wear of the two wheels was tested through grinding of granite, during which grinding forces were measured and the wear states of diamond grits were observed. It is shown that grits covered with brazing alloy exhibited stronger self-sharpening ability and fracture resistance. Therefore, the wheel with covered diamonds performed lower grinding force and better wear performance.

Performance of Brazed Diamond Wheel in Grinding Cemented Carbide

A kind of brazed monolayer diamond grinding wheel was developed with a relatively regular distribution of grains on the wheel surface. Grinding performances of this kind of brazed wheel in the surface grinding of cemented carbide were studied. The experiment results show that the grinding forces ratio becomes higher with the increasing of the maximum undeformed chip thickness and the specific energy falls with the material removal rate during grinding cemented carbide process. Under certain grinding conditions, the material was removed almost through plastic deformation and good surface quality is gained. Furthermore, the grits of the brazed diamond grinding wheel fail mainly in attritious wear modes other than pull-out ones in conventional electroplated and sintered diamond tools, which indicates that the strong retention of brazing alloy to the diamond grits and longer service life of this kind of wheel.