Abrasive Tools Research Articles

Consideration of chemically‐induced damage in a thermo‐electrically coupled system

AbstractElectro‐chemical machining (ECM) allows the removal of material based on the effect of anodic dissolution and without mechanical contact. Thus, it avoids tool abrasion as well as influencing the surface quality, for instance due to formed dislocations and/or damage. Due to that, ECM is a very attractive machining process for high strength materials such as titanium.The effect of anodic dissolution is a result of a present electric current in combination with the contact with an electrolyte. We show a material model, which enables to predict the mentioned effect by use of a chemically motivated damage of the material based on Faraday's law. After the approach's introduction, we will address its consideration within a thermo‐electrically coupled finite element method by using effective material parameters that differ between metal and electrolyte. The presentation is completed by the numerical results, which show the method's ability to simulate the ECM process.

Design of a novel fixed abrasive petal-shaped lapping tool and material removal uniformity experiments on K9 glass

A novel fixed abrasive petal-shaped lapping tool is proposed to achieve the material removal uniformity based on finite element method (FEM) and mathematical analysis. The cross-sectional profile of the petal-shaped lapping tool is revealed according to the numerical analysis based on the in-plane stress distribution of disk elastomer tools in contact with the workpiece, which is shown and analyzed for the first time. Then, the practical experiments are carried out on the K9 glass plane workpieces to study the characteristic of the surface quality evolution and the material removal uniformity. Results show that the increasing material removal amounts along the radius are all suppressed under different experimental conditions, where the coefficients of variations of the two experimental groups with the better results are as low as 0.077 and 0.085, respectively. Moreover, the surface roughness Sa and Ra along the radial direction after lapping reach as low as 142 nm and 30 nm for the optical glass, achieving a drastic improvement of 77.2 % and 88.8 %. Thus, the design strategy of lapping tool with special structure will explore a new path of fabricating more specific tools in the field of ultraprecision manufacturing.

Finishing performance of polyurethane-based flexible tools fabricated using solvent casting and particulate leaching method

Oxygen-free high thermal conductivity (OFHC) copper is a common material for mirrors in different optical applications. As it is a soft material and easy to scratch, the nanofinishing using traditional finishing processes is difficult. A flexible abrasive tool that can adapt to the shape of the component and apply uniform and gentle pressure is required to achieve a high-quality surface finish on the soft materials. Flexible abrasive tools are fabricated using the solution casting and dissolution method with open porous microstructure and uniformly dispersed silicon carbide particles in a polyurethane polymer matrix. Mechanical and finishing characteristics of the fabricated tools are obtained under dry and wet conditions. The developed tools are self-lubricating and self-replenishing, reducing tool wear and eliminating burn marks on finished surfaces. Scanning electron micrographs and energy dispersive spectroscopy are used to investigate the tool microstructure and abrasive particle distribution before and after finishing. The mechanical behaviour of tools is studied using a dynamic mechanical analyser. Porosity is measured using the interconnected void volume, and fluid absorption rate is calculated through weight measurement before and after fluid absorption. The surface finish of finished surfaces is analysed using an optical surface profilometer. Results show that the flexible abrasive tool performs the best under wet conditions. In a single pass, a wet salt-leached tool achieved a reduction of 42.2 % on a surface having a lower initial roughness, whereas a wet pure polymer tool achieved a reduction of 45.7 % on a surface having a higher initial roughness. Finally, areal surface roughness of 34 nm is achieved in 16 mins of finishing experiment using pure polymer tool followed by salt-leached tool.

Technological Aspects of Variation in Process Characteristics and Tool Condition in Grinding Process Diagnostics

The article presents the technological aspects of the diagnostics of grinding processes. The main features of the grinding process and their importance in diagnostic issues are discussed. Selected issues of research and assessment of the condition of the active surface of grinding wheels are presented. The authors pointed out that the parameters used to assess the topography of the ground surfaces do not have sufficient possibilities to differentiate the surface condition of the grinding wheels. This publication draws attention to the possibility of using new dedicated parameters to assess the properties of the grinding wheel surface. These parameters have a high ability to differentiate changes occurring as a result of the abrasion of grain vertices, their chipping or loading of the grinding wheel surface. The methodology of assessing the processes of abrasive grain wear and changes in the shape and dimensions of the grinding wheel, taking into account the probabilistic features of the grinding process, was formulated. The directions for the development of abrasive tools are presented, pointing to hybrid tools with a multi-phase structure, modified by additions of abrasive aggregates. A new research direction has also been formulated on the use of additive technology to produce specialised abrasive tools, including those with built-in process sensors.

Morphology and Physico-Mechanical Properties of Resin-bonded Palm Kernel Shell and Coconut Shell Grain-based Sandpaper Composites

Due to the challenges associated with using crude oil-derived phenolic- or thermoplastics-based materials, agro-based composites have been used as alternative abrasive grains for abrasive tool manufacturing. This paper examines the morphology and physico-mechanical properties of resin-bonded palm kernel shell (PKS) and coconut shell (CNS) grain-based sandpaper composites and their wear performance. The PKS and CNS were collected, pulverised and screened into 250 and 500 μm grainsizes and mixed at ratios of 1:1, 1:2 and 2:1, respectively. Methyl-ethyl-ketone-peroxide and cobalt naphthalene of 1.5 wt. % each were utilised as hardener and catalyst, respectively for proper bonding of the aggregates with unsaturated polyester resin of compositions 12, 15, 18, 21 and 24 wt. %, respectively. To produce the sandpaper samples, the aggregates were compacted at a pressure of 15 MPa and the samples were cured and their morphology, mechanical, and wear properties were investigated.The shatter index, hardness, and compressive strength varied from 66.36% to 95.76%, 6.52 to 11.3 HRB, and 4.41 to 7.24 MPa, respectively. The wear resistance varied from 0.94 to 1.54 mg/m at 50 oC, and 1.02 to 2.09 mg/m at 150 oC. The properties of the aggregates made from PKS and CNS were found to have much influence on the performance parameters of sandpaper composites.

Effects of Ti Containing Cu-Based Alloy on Sintering Mechanism, Element Diffusion Behavior and Physical Properties of Glass-Ceramic Bond for Cubic Boron Nitride Abrasive Tool Materials

Ti containing Cu-based (TC) alloy reinforced glass-ceramic bond was fabricated for cubic boron nitride (CBN) abrasive tool materials, and its crystal composition, phase transformation, sintering activation energy, microstructure, element diffusion mathematical model, physical properties, and the bonding mechanism between the TC alloy reinforced glass-ceramic bond and the CBN grains were systematically investigated. The results showed that the structure, composition and sintering behavior of glass-ceramic were influenced by TC alloy adding. The generated TiO2 affected obviously the precipitation of β-quartz solid solution Li2Al2Si3O10, thus improving the relative crystallinity, mechanical strength and thermal properties. By establishing the mathematical model for element diffusion, the element diffusion coefficients of Ti and Cu were 7.82 and 6.98 × 10-11 cm2/s, respectively, which indicated that Ti diffused better than Cu in glass-ceramic. Thus, Ti4+ formed a strong Ti-N chemical bond on the CBN surface, which contributed to improving the wettability and bonding strength between CBN and glass-ceramic bond. After adding TC alloy, the physical properties of the composite were optimized. The porosity, bulk density, flexural strength, Rockwell hardness, CTE, and thermal conductivity of the composites were 5.8%, 3.16 g/cm3, 175 MPa, 90.5 HRC, 3.74 × 10-6 °C-1, and 5.84 W/(m·k), respectively.

Study on wear simulation of diamond abrasive tool for rotary ultrasonic grinding

The aim of this study is to explore the wear mechanism of diamond grinding tools in rotary ultrasonic grinding process and complete the simulation study of micro wear state of diamond grinding tools in different processing stages. Primarily, the morphology of single diamond abrasive grains is analyzed and studied, and a three-dimensional irregular abrasive grain simulation is carried out according to the morphology characteristics of diamond abrasive grains. Then, the center distance and spatial distribution law between diamond grits are obtained by calculation, and the discrete three-dimensional morphology simulation of diamond abrasive end face is completed based on the virtual lattice theory. Through the rotary ultrasonic grinding experiment, the wear form of diamond grits and the mathematical model of the wear amount of diamond grits changing with the removal amount of workpiece material are determined. The wear simulation of diamond abrasive tool with different workpiece removal is completed by using the mathematical model obtained from experiments. Last section, the number of abrasive particles in the simulation model and the wear amount of the abrasive tool are compared and analyzed with the corresponding experimental results. The above research provides a new research method for exploring the wear mechanism of diamond abrasive tools.

Influence of Honing Parameters on the Quality of the Machined Parts and Innovations in Honing Processes

The article presents a literature review dealing with the effect of the honing parameters on the quality of the machined parts, as well as with the recent innovations in honing processes. First, an overview about the honing and the plateau-honing processes is presented, considering the main parameters that can be varied during machining. Then, the influence of the honing parameters on surface finish, shape deviation and material removal rate is presented. Finally, some special and innovative applications of the honing process are described. For example, honing with variable kinematics allows obtaining oil grooves that are not rectilinear but curvilinear, in order to reduce the temperature of the part during machining and thus achieving better surface finish and lower shape deviation. Automation of the honing machines is useful to improve both the production and the verification process. Another innovation consists of using 3D printed tools in honing processes, which will help to obtain abrasive tools with complex shapes, for example by means of powder bed fusion processes.

КАМЕННЫЙ ИНВЕНТАРЬ НЕОЛИТИЧЕСКОГО ПОСЕЛЕНИЯ ЧЭС-ТЫЙ-ЯГ

Ches-tyi-yag is the most important defining site of the Middle Neolithic Lower Ob region with ceramics of the Chestyag cultural type. The collection of stone inventory from five dwellings and two buildings, investigated by excavations, is distinguished by cultural homogeneity, seriality of mor¬photypes of tools and debitage. The article for the first time analyzes in detail the collection of flint inventory of the settlement (1 139 items) from the standpoint of technical, morphological and typological approaches. Grinded tools and abrasive tools are not considered. In all dwellings, the same varieties of flint were used, quartz products are rare. The industry is characterized as flaking: stadial concrete-situational direct percussion is combined with bipolar technique. A few blades are more often irregular. Among the tools, scrapers of various shapes and flakes with edge retouching predominate, designed for performing cutting, scraping, sawing functions. Small chisel-shaped tools are typical, there are perforators and carvers, and combined tools are frequent. Arrowheads on large irregular blades carry a double-sided edge retouching. The technique of incisor chipping was not used. The bipolar technique was also used to form the blades and rear parts of the tools (undercutting, thinning and reworking the implements), as well as for fragmentation and re-registration of finished tools. The flint inventory of the Ches-tyi-yag settlement according to the technique of splitting, of course, belongs to the circle of the taiga Neolithic of Western Siberia, representing the original flint flake industry with a bright typologically pronounced tool set.

Increasing of bakelite binder strength due to use of microwave energy in heat treatment of semi-finished abrasive tools

The results of a study of the influence of the type of heat treatment on the strength and structural characteristics of an abrasive tool on a bakelite bundle are presented. The prospects of using microwave energy in the production of polymer composites are noted. In particular, the use of microwave heat treatment makes it possible to reduce the duration of the technological cycle, specific energy consumption and increase the strength of the finished product.

Abrasive water jet tool passivation: from mechanism to application

The passivation process of a tool is a necessary step in the manufacturing process, which could improve tool life and machining efficiency by removing microscopic defects of in tool surface (such as burrs and micro cracks) after grinding or polishing. The abrasive water jet passivation (AWJP) is one of the most commonly used processes for carbide, ceramic and steel materials tools. Nevertheless, the complex action law from passivation to machining performance is indistinct, which makes passivation parameters rely on empirical summaries. To fill this gap, this paper concentrates on the detailed review of AWJP and comprehensive assessment between machining performance and AWJP parameters. Firstly, the mechanism of AWJP is analyzed, and the influence law of jet parameters on the tool nose radius is investigated. Secondly, the effect of tool nose radius on the force in turning and milling are summarized and analyzed. The jet pressure, abrasive concentration and jet time are positively correlated with the tool nose radius. Additionally, then the tool nose radius is positively and negatively correlated with cutting force and tool wear, respectively. Finally, future directions regarding the different parameters in AWJP and the machine tool for tool passivation are proposed: to reveal the complex nonlinear relationships between the parameters in AWJP. Develop economical, practical and efficient tool passivation machine tools to improve passivation efficiency and passivation accuracy and apply them to domestic tool passivation technology.

Grinding the side surfaces of the spiroid cylindrical gear worm turns with a tapered wheel

Information about the worms’ production technology of spiroid cylindrical gears is given. A method of the profile analytical calculation of a disk abrasive tool is proposed, providing the possibility to profile grinding wheels for various types of ruled helical surfaces: Archimedean, convolute, involute, etc. The use of the calculation methodology makes it possible to achieve high accuracy in processing the active (working) side surfaces of a hardened grinding worm; it sharply reduces the wear intensity of the spiroid wheel associated with it, the ring gear of which is made of bronze.

ЗАВИСИМОСТИ ПОКАЗАТЕЛЕЙ ШЛИФОВАНИЯ МИКРОПОРИСТЫХ ПОКРЫТИЙ ОТ ТЕХНОЛОГИЧЕСКИХ ФАКТОРОВ

Wear-resistant nickel-based thermal coatings used to restore worn parts are universally recognised. However, these coatings are among hard-to-machine materials as the abrasive machining causes some challenges. The main cause of poor machining performance of the coatings is due to their specific physical and mechanical properties that result in a rapid grinding wheel wear. The paper proposes a solution to improve the grinding process of the coatings by identifying optimal values of machining process factors. The process factors include cutting mode and wheel performance values that are crucial for high technical and economic indices. The paper discusses the obtained values of machining performance Qm and wear rate Qa of abrasive tools used for infeed cylindrical grinding of coatings. The research revealed dependence of machining perfor- mance and grinding wheel wear rate on various process factors: cutting modes such as the wheel speed, workpiece rotation speed and radial feed speed; grinding tool characteristics such as the grain size and hardness. The paper outlines the methods and results of abrasive machining of microporous coatings that was performed according to the infeed cylindrical grinding system and employed a fractional factorial experiment. Levels of process factors, the level values and the variation intervals are also presented in the paper. The main calculation formulas may be found here too. The paper highlights the conditions for conducting experiments and provides a theoretical basis for the selection of the size and characteristics of grinding wheels. Also, it describes the chemical composition of the thermal coatings and the prototypes dimensions. Results of the fractional factorial experiment were duly processed, linear mathematical models of the technological process were obtained, and their adequacy was checked. The paper analyses the derived empirical dependencies and gives scientific substantiation of the findings based on the metalcutting theory. The obtained dependencies could be used for solving the problem of optimising the cutting modes and improving the grinding wheel characteristics by minimising the process cost.

Methods and Test Benches for Cutting Tools Testing—A Review

Mechanical mining is a widely used method of separating materials from the face to obtain a useful mineral (e.g., coal, metal ores, salts, and diamonds), to make underground workings (e.g., mine galleries, tunnels, and underground garages), level roads, shape slopes, or to dig ditches. Mechanical mining is applied in the mining branch, tunnelling, road, and construction industries. Depending on the mechanical properties of the rocks, most frequently described by uniaxial compression strength, various machines and tools are used. The methods of mining high-strength abrasive rocks that have been used and developed in recent years are particularly applicable to the mining of copper, gold, tungsten, platinum ores, diamond deposits, and tunnelling. In addition to rock strength, the effectiveness of the mining process is affected by abrasiveness, which influences the rate of abrasive tool wear. Therefore, in various research and development centres, but also in production companies, tools are tested on unique stands. Tests are carried out to determine the cutting resistance and assess the wear rate. This article reviews methods and benches for testing mining tools, conical picks, and discs. Various solutions for testing single tools and cutting heads have been presented. The analysis conducted has revealed that despite the large number and great diversity of different test benches, there are no appropriate methods and stands for testing the wear rate of materials intended for mining tools.

Fabrication and Characterization of Gel-Forming Cr2O3 Abrasive Tools for Sapphire Substrate Polishing

This paper proposes a gel-formed abrasive tool to address the problem of abrasive agglomeration in a traditional hot-pressing abrasive tool. The effect of Polyimide resin content on the mechanical properties of the gel abrasive tools were tested, and a comparison of the mechanical properties of the gel abrasive tool and the hot-pressing tool was conducted. An orthogonal experiment was conducted to explore the best combination of machining parameters. A polishing experiment of sapphire was conducted to compare the processing effect of the gel abrasive tool and hot-pressing tool. The results from testing the mechanical properties showed that the tensile, flexural, and impact strength of the gel abrasive tool was better than that of the hot-pressing abrasive tool. The results of the orthogonal experiment showed that the best process parameters of the gel abrasive tool were a spindle speed of 900 rpm, a feed rate of 8 μm/min, and a grinding depth of 16 μm. The polishing experiment showed that the gel abrasive tool had a better processing effect on sapphire. The sapphire surface processed by the gel abrasive tool had no deep scratches, and an ultrasmooth surface could be obtained after chemical mechanical polishing (CMP).

Gear Wheel Finishing with Abrasive Brushing Tools to Improve the Surface Quality of Tooth Flanks for the Industrial Application

A high surface quality of tooth flanks can improve the service life and the performance of gears, as well as reduce acoustic emissions. However, high demands on the gear geometry pose a challenge for the finishing of tooth flank surfaces because the dimensional accuracy that can be achieved with modern grinding processes must not be impaired by the finishing process. A preceding study has shown fundamentally that profiled abrasive brushing tools can be used to improve the quality of individual tooth flank surfaces. Due to the integration into the grinding machine, it represents a promising alternative to common finishing applications. Before the process can be used in an industrial environment, process reliability and tool life must be examined. For this purpose, complete reference gearwheels (39 × 10) were finished with the brushing tools. It could be shown that the surface roughness can be reliably reduced by ΔRa ≈ 0.2 µm by using a single brush for an entire gearwheel without changing the gear geometry. In addition to the influence of the tool specifications on the work result, the influence of the initial roughness after grinding was considered in particular. It was found that the achievable surface roughness depends significantly on the depth of the grinding grooves, as these are retained as desired, while the roughness peaks are fully smoothed. Furthermore, a device for the machine-integrated profiling and dressing of brushing tools was successfully designed, implemented, and tested.

Geopolymer-based grinding stones utilizable in metal machining

This article presents partial results of a project focused on the Research and development of new grinding tools fixed with hybrid binder based on inorganic polymers. The clay-slag geopolymer with corundum abrasive grains was first time used to prepare novel abrasive tools for metal grinding. The effect of brown and white corundum grains of different grain sizes and content has been investigated. The experiments performed on a rusted steel tube on a lathe along with subsequent scanning electron analysis (SEM) have confirmed the grinding properties of geopolymer grinding stones. The grinding traces detected by SEM analysis correspond to the incorporated amount of the abrasive and the size of the grain used. The results have proven that, in case of metal grinding, a geopolymer matrix can substitute for ceramic binder in grinding tools. The geopolymer grinding stones are an opportunity to sustainable development of a new generation of abrasive materials which utilize waste materials, save primary raw material resources and energy consumption and has a minimum impact on the environment.

Influence of the addition of niobium oxide on the properties of fused aluminum oxide used in abrasive tools

Fused alumina is a material used in the manufacturing of abrasive tools, due to its high fusion point, great hardness, and mechanical toughness. In this context, this study addressed the influence of niobium addition on the properties of fused alumina for abrasive applications. A comparison was also made between this oxide and the brown fused alumina and the white fused alumina traditionally applied in this market, using different characterization techniques, such as particle size characterization, scanning electron microscopy, real and bulk density, chemical analysis, fracture resistance, and abrasiveness indexes. Among the main findings of this study, it was possible to observe that the addition of niobium to fused alumina significantly increased the fracture resistance and abrasiveness indexes compared to the brown and white fused alumina.

Tailoring of Dissimilar Friction Stir Lap Welding of Aluminum and Titanium

An approach was proposed to optimize dissimilar friction stir lap welding of aluminum and titanium alloys. The basic concept of the new technique included (i) the plunging of the welding tool solely into the aluminum part (i.e., no direct contact with the titanium side) and (ii) the welding at a relatively high-heat input condition. It was shown that sound welds could be readily produced using an ordinary cost-effective tool, with no tool abrasion and no dispersion of harmful titanium fragments within the aluminum side. Moreover, the intermetallic layer was found to be as narrow as ~0.1 µm, thus giving rise to excellent bond strength between aluminum and titanium. On the other hand, several important shortcomings were also revealed. First of all, the high-heat input condition provided significant microstructural changes in the aluminum part, thereby resulting in essential material softening. Furthermore, the new approach was not feasible in the case of highly alloyed aluminum alloys due to the relatively low rate of self-diffusion in these materials. An essential issue was also a comparatively narrow processing window.

Material removal and belt wear in laser assisted grinding TC17

ABSTRACT Titanium alloys have high hardness and low plasticity, there will be large cutting force and serious tool wear during machining. Laser-assisted grinding can significantly improve its machinability, but the wear mechanism of abrasive tools and its influence on material removal during machining have not been well revealed. In this paper, the variation of cutting force under different laser power, laser scanning speed and feed speed were studied. In addition, the influences of different laser powers on material removal was also investigated. At the same time, the abrasive belt wear in laser-assisted grinding and conventional grinding was compared. The results indicated that increasing the laser power can reduce the cutting force. When the laser power increased from 7.2W to 9.6W, the cutting force showed the maximum change trend, which decreased by 46%. Enhanced material removal and increased plastic flow with increasing laser power. Increasing the laser scanning speed and workpiece feeding rate will also increase the cutting force. In addition, laser-assisted grinding can reduce belt wear compared with conventional grinding under the same grinding parameters. Therefore, laser-assisted grinding has an important potential role in the field of grinding.