Diamond Dresser Research Articles

Evaluation of the grinding performance of vacuum-brazed diamond dressers in dentistry

Evaluation of the grinding performance of vacuum-brazed diamond dressers in dentistry

Shaping the Topography of the Active Surface of a Ceramic Grinding Wheel with a Stationary Multi-Point Diamond Dresser

Shaping the Topography of the Active Surface of a Ceramic Grinding Wheel with a Stationary Multi-Point Diamond Dresser

An Experimental Investigation of the Effects of Dressing and Grinding Parameters on Sustainable Grinding of Inconel 738 Used for Automated Manufacturing

The significant effect of the dressing process on the surface of the grinding wheel (GW) and the need to provide an optimal dressing condition are the requirements of reduction machining time and energy consumption in the sustainable grinding process. In this study, for the first time, the results of changes in the parameters of the dressing process and changes in the topography of the grinding surface on the surface roughness of the Inconel 738 have been presented using single-edge and four-edge diamond dressers. The use of minimum quantity lubrication (MQL) and wet condition are other variables in this study to reduce the consumption of cutting fluid and prevent its destructive effects on the environment. The results indicate that the MQL technique increases the grinding performance of Inconel 738 by reducing ground workpiece surface roughness and decreasing the coolant–lubricant consumption comparing to the conventional wet grinding process. Additionally, it has been found from the experimental results that applying a single-edge dresser generates finer topography on the grinding wheel and, consequently, has a better surface finish in the grinding process compared to the multipoint diamond dressing tool with the same dressing and grinding parameters. In other words, increasing the dressing feed rate during dressing of the grinding wheel using a multipoint dresser makes a finer wheel surface topography and as a result decreases the surface roughness of the ground workpiece compared to a single-edge dresser. With multipoint diamond tools, the grinding performance during the life of the dressing tool also tends to remain more consistent, which is a definite advantage in automated production. Therefore, application of a multipoint dresser leads to a reduction in dressing time and increased production capability.

Influence of Internal Grinding Wheel using Aluminium Oxide with Boron Nitride and its Relation to Dressing and Surface Roughness

Performance of grinding wheel depends on different factors from dressing operations to wheel topography. This will directly show effect on grinding force, surface quality and wheel durability. During grinding, an improved wheel should reduce the number of passes as well as the dressing time (wheel gets loading) to increase the production rate and minimize the total cycle time to complete the parts. This paper presents several process parameters to obtain the improved surface roughness and round tolerance such as coarse dress depth of cut 30 microns for the first pass, fine dressing depth of cut 20 microns for the second pass and a dressing speed and feed rate of 0.5m/min respectively. The experiments with the optimal dressing parameters have been considered to check the wheel durability and its performance. The parameters investigated were wheel life, surface roughness and round tolerance from the experiments with different cutting variables like depth of cut, speed, feed rate and percentage of wheel depletion. For this purpose, a single point diamond dresser with four different test samples using Aluminium Oxide (Al2O3) with Boron Nitride (BN) for internal grinding wheels were chosen for the experiment.

The mechanism investigation of ultrasonic roller dressing vitrified bonded CBN grinding wheel

To clarify the ultrasonic roller dressing mechanism of the vitrified bonded cubic boron nitride grinding wheel (V-CBN), the collision number model between the diamond dresser and CBN grits was established based on the geometric and kinematics analysis. The influence of each dressing parameter on the collision number was analyzed and discussed. The grinding experiment was performed on the bearing raceway with the dressed V-CBN grinding wheel, results obtained discovered that there was an inverse relationship between the collision number and the surface roughness and runout of the workpiece. Additionally, compared with conventional dressing, ultrasonic dressing has the advantage in improving the surface quality because it can produce more collision numbers and raise grit retention. In words, the collision number can be used to predict the dressing effect, which provides a reference for formulating an appropriate dressing process for V-CBN to improve the workpiece surface quality and production efficiency.

Improvement of Physical and Mechanical Characteristics of Synthetic Diamond Powders Synthesized from Ferroalloys for Increasing the Wear Resistance of the Diamond Dressing Tool

Improvement of Physical and Mechanical Characteristics of Synthetic Diamond Powders Synthesized from Ferroalloys for Increasing the Wear Resistance of the Diamond Dressing Tool

Effect of the dressing process on the surface roughness in cylindrical grinding of Ti6Al4V alloy using stationary diamond dressing tools

The current study investigates the influence of the dressing process of the vitrified bonded microcrystal alumina grinding wheel on the roughness of the machined surfaces in cylindrical grinding of Ti6Al4V alloy using different types of stationary diamond dressing tools. For the research, four types of dressers were selected, which differ from each other by number, size and location of diamond cutting elements. Each dresser has been tested at four different dressing feed values with the same dressing depth. Two sets of experiments were conducted to determine the tendency of grinded parts roughness parameters change depending on the dressing feed for each type of diamond dressing tool at two values of grinding feed. A comparative analysis was carried out to show the dressing feed influence and the effect of the diamond dresser type select on the roughness parameters of the grinded surfaces.

Experimental investigation of the effects of dressing and coolant-lubricant conditions on grinding of Nickel-based superalloy-Inconel 738

In grinding operation, wheel topography influences the workpiece surface quality, grinding forces, abrasive grain wear and wheel loading. The difficulties associated with grinding nickel-base superalloys are mainly attributed to the high strength and low thermal diffusivity of these materials. Their high strength leads to high removal energy. The application of green machining techniques for sustainable manufacturing becomes more and more attractive nowadays to reduce the consumption of energy and cutting tools and cut fluids and consequently decrease the production costs and environmental effects. In this study, the effect of dressing parameters and wheel topography on Minimum Quantity Lubrication-MQL grinding performance of Nickel-base superalloy-Inconel 738 is investigated. In other words, to generate different grinding wheel topographies, depth of dressing and dressing speed has been changed during dressing and conditioning of vitrified Al2O3 wheels using a single point diamond dresser. After dressing grinding wheels, machining tests have been conducted to study the influence of the wheel topography and coolant-lubricant types on the performance of grinding operation (workpiece surface quality and wheel loading). The tests have been performed in the presence of fluid as well as MQL with compressed air. The results show that applying MQL technique with the optimized dressing conditions improves the grinding performance of Inconel 738. Minimum quantity lubrication implemented in the grinding process is one of the realistic alternatives that can rise the abrasive processes on a sustainable level.

Micro-analysis of the contact zone between vitrified bonded CBN segment and diamond grit during the dressing process

This study investigates the contact zone between vitrified bonded cubic boron nitride abrasive (V-CBN) wheel and diamond dresser during dressing process. For that, the grinding experiment of single-grit diamond dresser has been conducted on V-CBN segment to approach the actual dressing process. The segments are ground under different undeformed chip thickness. Acoustic emission (AE) signal was used to evaluate the grinding wheel wear progression. Results obtained indicate that the diamond dresser wore severely. Meanwhile, the chemical reaction and physical adhesion took place during the grinding process. With the increasing of wear ratio, the AE rms values also showed an increasing trend.

Mathematical modeling of the surface roughness of the grinding wheel during straightening

Purpose. Research on the mechanism of influence of the straightening conditions of the grinding wheel, including the relative oscillations of the wheel and a multipoint diamond dresser, on the roughness of the ground surface and other machining results. Methodology. Straightening a grinding wheel with a multipoint diamond dresser is a process of high-speed destruction of a hard, abrasive material and its bond under the instantaneous forces, abrasive grains with a hard surface of a diamond crystal. During the grinding wheel straightening, the total component of normal forces causes correspondingly less elastic deformations in the wheel straightening tool system, which increases the accuracy of the geometric shape of the grinding wheel working surface. Findings. The research results make it possible to determine the parameters of the surface roughness of a workpiece and to find ways to control it to increase the efficiency of the grinding process. Originality. The regularities of the influence of the grinding wheel straightening conditions on the state of its working surface have been established. The paper shows that the initial arrangement of grains along the normal to the surface of the wheel is determined by its characteristics. When the abrasive grains hit the surface of the straightening tool, some of the vertices are chipped off, as a result of which the density of the grain vertices on the outer surface of the wheel increases. The straightening process was further developed in the direction of the non-uniform character of the location of the vertices of abrasive grains. The distribution of the grain position at the wheel bond depends on the straightening conditions. Since the removal of the allowance in the process of grinding is carried out by the most protruding grain vertices, then, consequently, the result of grinding will depend on their location and the conditions for the wheel straightening. Practical value. Application of the research results obtained in the work, namely, mathematical modeling of the surface roughness of the grinding wheel during straightening, makes it possible to calculate the roughness parameter of the ground surface. The work also shows that the level of chipping of the grain vertices depends on the grinding wheel straightening conditions, in particular, on the value of the axial feed of the straightening tool. In this case, lower stresses arise in the grains and the bond, and the tool works as a harder one. Straightening conditions affect the stability of the grinding wheel and its self-sharpening process in the machining zone. This determines the significant role of straightening in the results of the grinding process.

Experimental Analysis of a Grinding Wheel by Increasing Multiple Passes in Dressing

When sharpness of grinding wheel becomes dull, a dressing is an operation performed because of glazing and loading, dulled grains and chips are removed (crushed or fallen) with a proper dressing tool to make sharp cutting edges and simultaneously, make recesses for chips by properly extruding to grain cutting edges. The basic dressing operation consists of removal of grains and swarfloaded, generation and exposure of the new cutting edges on the cutting surface of the grinding wheel. The former is obtained by digging out the swarf and the latter is achieved by fracturing the existing abrasive grains and allowing desired protrusion of abrasive particles on the cutting surface. Both of the above operations are carried out using a diamond dresser (3 carat). A part of this work focuses on finding the optimum dressing parameters (depth of cut of the dresser and the number of passes) which gives optimum cutting condition for grinding using conventional method of grinding using diamond dresser, Water Jet Machine and Abrasive Water Jet Machine. The trial run on the conventional machine with different parameters was performed. The results obtained prove the possibility of using directly in the industrial practices.

The use of high-resolution methods of research in the design of the diamond-matrix interface to increase the durability of the diamond tool

The results of studying fundamental and applied problems regarding the formation of boundary layers between diamond and carbide matrix are presented with the goal to develop a highly resistant diamond tool. The new approaches to the synthesis of diamond-carbide materials combining diamond metallization and sintering in a single-stage technology are presented. The developed technology eliminates the re-heating of a metallized coatings which results in their destruction and enhanced graphitization of diamond (these phenomena restrict using metallization procedure to improve diamond retention and synthesis of high-functional composites for diamond tools). The goal of the study is analysis the structural and phase state of the «diamond – carbide matrix» interface in a diamond tool obtained by the new technology and the main factors determining the level of diamond retention in the presence of a metallized coating. Unique opportunities provided by modern high-resolution methods of research were used in the study. The elemental composition and morphological features of the diamond-matrix interface were studied using the methods of scanning electron microscopy, atomic force microscopy, X-ray microanalysis and Raman spectroscopy. Identification of the reaction products, including non-diamond carbon was performed. It is shown that the introduction of the powder-metallizer significantly modified the contact boundaries and provide conditions for improving the chemical and mechanical adhesion of the diamond-matrix system. The formation of the well-developed nano- and sub-microscale roughness of the diamond surface and dense filling of the existing voids with nanoscale layers of metal-infiltrate was revealed. The multilevel organization of highly structured elements of the transition zone with the minimal graphitization ensured the monolithic character and strength of the diamond-matrix bond. Comparative service tests of preproduction and control samples of diamond dressers proved the efficiency of developed hybrid technology (the specific performance of diamond tools increased by 39 – 45%). New fundamental and applied results have been obtained in the field of studying interface zones in crystalline multiphase systems that can be used to regulate adhesion phenomena at the interphase boundaries and develop highly efficient composite materials.

Technology of Production of Diamond-Abrasive Composites with Metal Matrix

The prospects of using the method of explosive pressing for solving urgent problems of creating high-performance diamond composites for instrumental purposes on binders of powders of fairly cheap materials are substantiated. Purpose of this work is to develop the technology of diamond-abrasive composites synthesis from powders mixtures of natural diamond and widespread low-cost iron-carbon alloys which combines explosive pressing and subsequent short-term high-temperature heating. The processes of varying the compositions of diamond-metal powder mixtures, the parameters of their explosive pressing and the modes of subsequent heat treatment of the resulting compacts are studied. It is shown that the use of explosion energy at the stage of powder briquetting opens up new opportunities for the production of high-performance diamond-containing materials with a matrix of iron-carbon alloy powders. This is due to the specifics of the explosive action which results in the activation of the bonding material which becomes obvious with further high-temperature heating in its intensive hardening and acceleration of diffusion processes. It is revealed that the shock waves create thermobaric conditions that allow for better preservation of the diamond component than with traditional methods of sintering. Samples of abrasive diamond composites with wear resistance corresponding to the level of wear resistance of industrial diamond dressers but with half the consumption of diamond raw materials were obtained.

Material removal efficiency improvement by orientation control of CMP pad surface asperities

This paper presents a novel method of improving material removal efficiency in the chemical mechanical polishing (CMP) process by optimizing the surface asperity orientation with respect to polishing motion. Feret's diameter plays a key role in increasing the number of working abrasives. Based on Feret's diameter model, an optimization method is proposed for the conditioning motion of a diamond dresser against a CMP pad. The radial velocity component of the dresser on the CMP pad is maximized by considering its direction of motion based on kinematic motion simulation. In addition, the pad cut rate profile is optimized to be uniform. Analytical and experimental investigations show that the ratio of radial and tangential velocity components is improved, yielding a larger Feret's diameter and 15% increase in the material removal rate.

Some Experimental Aspects of Grinding Soft Steel Under Different Machining Conditions

In this study, the effects of dressing parameters, wheel topography and machining environment on grinding performance of soft steel are investigated. To generate different grinding wheel topographies, dressing speed and depth have been changed during dressing of vitrified Al2O3 wheels using single point diamond dresser. After dressing of grinding wheels, machining tests have been conducted to study the influence of the wheel topography and coolant-lubricant types on the performance of grinding operation. The results suggest that MQL is more suited to grinding of soft material in the finishing step (shallow cut) with the finest dressing than wet and dry grinding.

Structure of a Diamond–Matrix Interface and Durability of a Diamond Tool Fabricated by the Metallization of Diamond with Chromium during Sintering of the WC–Co Briquette with Copper Impregnation

The structure, as well as the elemental and phase compositions of the diamond–matrix interface of a diamond tool for abrasive wheel dressing, manufactured using a new hybrid technology, are studied. This technology combines the thermodiffusion metallization of diamond with chromium and sintering of a matrix based on a WC–6%Co carbide powder mixture with copper impregnation in a single cycle of the vacuum furnace operation. During matrix sintering, the compact arrangement of chromium powder particles around the diamond grains and the screening effect of the copper foil form favorable conditions that ensure the thermodiffusion metallization of diamond. Scanning electron microscopy, electron probe microanalysis, X-ray phase analysis, and Raman spectroscopy show that a metallized coating chemically bound with diamond is formed on the diamond surface in temperature-temporal modes and sintering conditions. The coating consists of chromium carbide and a solid solution of cobalt in chromium, which provides durable diamond retention in the copper-impregnated carbide matrix. Herewith, the matrix structure and microhardness, excluding the regions adjoining the diamond–matrix interface, remain the same as a matrix of a carbide powder mixture sintered in the absence of chromium. Comparative tests of similar diamond dressers show the high efficiency of the hybrid technology of formation of diamond-containing composites for tool application. It is shown that the specific productivity of a dresser prototype fabricated using the hybrid technology was 51.50 cm3/mg when dressing a grinding wheel made of green silicon carbide, which is 44.66% larger than a similar indicator of the same type of check dresser formed using the traditional method.

Specifying the Process Parameters for Diamond Dressing of Grinding Wheels

Theoretical and experimental investigations have provided a deep insight into the process of diamond dressing of vitrified grinding wheels under the mechanisms of micro- or macrofracture of abrasive grits. This permits determining the process parameters dressing in coarse and finish grinding operations. The authors propose equations for finding the depth of dressing for various types of have been proposed for different wheel working layer states.

Morphological evolution and grinding performance of vitrified bonded microcrystal alumina abrasive wheel dressed with a single-grit diamond

Abstract Dressing experiments under different conditions were carried out on a vitrified bonded microcrystal alumina abrasive wheel with a single-grit diamond dresser. The grinding performance of the as-dressed abrasive wheels was investigated. The dressing force, grinding force and the surface morphology of abrasive wheel and machined workpiece were studied to shed light on the relationship among the dressing processing vectors, morphology of abrasive wheel and the grinding performance. The results obtained show that the dressing forces increase with the increasing volume of the abrasive wheel material removed per unit time. The sensitive analysis reveals that the dressing feed speed take a greater effect than the single dressing depth on the dressing force. The self-sharpness of vitrified bonded microcrystal alumina abrasive wheel brings into some functions under certain dressing conditions, but a deep dressing depth would lead to an excessive abrasive self-sharpness, i.e. abrasive grits fall off and embed into the workpiece surface.

Optimization of the parameters for the rotary diamond dressing of grinding wheels

ABSTRACTThe object of this study was the optimization of dressing parameters used with rotary diamond dressers. A grinding wheel was dressed using different dressing factors and levels and the results were evaluated by the examination of test pieces ground using the dressed wheel. The surface roughness value of the test pieces was measured to determine the optimal dressing parameters. The effect of five dressing factors on surface roughness and work efficiency was investigated – dressing speed ratio, cross feed rate, dressing depth, dressing count, and smoothing count. The ranking of the dressing tests was determined using an Taguchi orthogonal array to evaluate the ground surface of the test pieces. The experimental data was analyzed and the signal/noise ratio was calculated. The quality characteristics were used to determine the optimal dressing parameters using principal component and Grey relational analyses. This approach allowed the optimal combination of factors and levels that would achieve a targeted grinding quality with favorable processing efficiency to be found.

Efficiency of Hybrid Sintering Technology for Cemented Carbide Diamond-Containing Composites with Impregnation, Including Thermal Diffusion Metallization of Diamonds

For the enhancement of chemical and mechanical adhesion of natural diamond particles with a hard-alloy matrix during the synthesis of diamond-abrasive composites the hybrid technology which combined in one technological process the thermal diffusion metallization of diamond particles and sintering by the developed scheme of the self-dosed impregnation is proposed. This technology does not include a reheating of the metallized coating that causes its destruction and enhances graphitization of diamond thus limiting the application of metallization method for improvement of diamond retention and creation of high-functional composites for diamond tools. Formation and preservation of adhesion-durable metallized coating is confirmed by experiments simulating the conditions of high temperature interaction of diamond with a carbide-forming metal and a hard-alloy matrix during the sintering of special samples using the regimes of developed technological process. The structural and phase state of the transition zone is studied by scanning electron microscopy, X-ray structure analysis and X-ray phase analysis of the partition surfaces of the contact zone between the diamond and the matrix obtained by tensile testing of special samples. Comparative service properties tests of prototype and control samples of diamond dressers confirmed efficiency of the developed hybrid technology for the creation of diamond tools.