Model-based manufacturing and application of metal-bonded grinding wheels

The tool properties of grinding wheels can vary in a wide range due to the variety of processes. The properties, in turn, affect the grinding process and the grinding results. Understanding the interdependencies from the initial manufacturing to the final grinding results is the key to achieve the target-oriented generation of the grinding wheel properties for the grinding task at hand. This paper presents a novel approach to model the interdependencies between the manufacturing of bronze-bonded grinding wheels and the resulting grinding behaviour. The manufacturing steps are described with sub models in order to forecast properties and application behaviour.     

Study on the grinding of advanced ceramics with slotted diamond wheels

Slotted diamond wheel grinding is a new machining technology. In this paper, an experimental study on the cutting force and the grinding temperature for ceramic face grinding using slotted diamond wheels is presented. Moreover, the empirical relationships related with the material removal rate, the surface roughness, the depth of cut, the wheel speed and the grain size are discussed. With these relationships, a temperature field for face grinding has been built. The work contributes to the fundamental theories for optimal design of slotted diamond wheels.     

Assessment method of cutting ability of CBN grinding wheels

In the paper authors described a method of CBN grinding wheel cutting ability evaluation and research results achieved with this method during grinding process. Research results, which allowed for verification of the method (e.g. measurements of grinding force components, surface roughness and waviness parameters and stress level in surface layer) were also presented.     

The influence of grinding process on forced vibration damping in headstock of grinding wheel of cylindrical grinder

The paper describes theoretical analysis of dynamics of system: machine–tool–workpiece for cylindrical plunge grinding. The functional as well as mathematical model of grinder equipped with hydrostatic bearing of grinding wheel spindle and hydrostatic slideways has been presented in the paper. Simulations based on that model allow qualitative investigation of grinding force characteristics and its influence on forced vibrations in grinder. Results of simulation supported the thesis, that grinding force significantly influences the forced vibration damping of headstock of grinding wheel.     

Engineered wheels for grinding of optical glass

This paper focuses on the evaluation of topographical parameters characterizing the influence on the behaviour and finally the process results by applying engineered diamond wheels in machining hard and brittle materials. Here, coarse-grained, single-layered diamond grinding wheels with electroplated abrasive layers and active-brazed, defined grain pattern have been dressed by a special conditioning process and used in precision grinding experiments on optical glass. The characterization of the abrasive layer topography was done by two topographical parameters, the specific total grain plateau area A′_G,total and the average grain cutting edge width b_G,a, determined by 3D-profilometry of replicated abrasive layers after each dressing step.     

Finishing characteristics of brittle materials by ELID-lap grinding using metal-resin bonded wheels

ELID-lap grinding is a method of constant pressure grinding which utilizes an electrically conductive wheel and the electrolytic in-process dressing (ELID) method. This method has the advantage of using micro grain-wheels above #10 000 and also, through simple modification, can be used on existing lap machines. To find the characteristics of metal-resin bonded wheels developed for ELID-lap grinding, experiments on the grinding of brittle materials were performed using wheels with a variety of grain diameters. The wheels used in the experiments were #8000, #120 000 and #3 000 000 metal-resin bonded diamond wheels (#8000 MRB-D, #120 000 MRB-D and #3 000 000 MRB-D wheels). The workpieces were silicon and glass. The results of the experiments showed that stable grinding can be achieved with the #8000 to #3 000 000 MRB-D wheels. With the #3 000 000 MRB-D wheel, very smooth surface finishes were obtained for both silicon (PV 2.8 nm) and glass (PV 2.5 nm). Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) observations indicated these surfaces to be very smooth in the order of several nanometers, obtained by mechanical removal using an ultrafine wheel.     

Form crush dressing of diamond grinding wheels

Form crush dressing is a method to profile diamond grinding wheels. Especially for complex profiles with intricate details and high accuracy an improved form crush profiling system has been developed. The system consists of a hydrostatically supported form crushing disc embedded in a swiveling axis. Form disc wear, which forms a major bottleneck in reaching high accuracy, has been minimized through the development of an advanced wheel synchronization control strategy. Various vitrified grinding wheels and a crushable metal bonded wheel have been tested to show the general applicability of the method to grinding wheels with brittle bond systems.     

Laser surface preparation of vitrified grinding wheels

A new method for surface cleaning loaded grinding wheels is introduced by applying CO₂ laser irradiation onto the grinding wheel surface. It was demonstrated that effective cleaning can be achieved by selection of the laser power flux and the duration of the irradiation. Fusion and evaporation of clogged metal chips play important roles in the laser cleaning process. It is suggested that high laser power irradiance and short irradiation duration are essential for effective grinding wheel cleaning. This paper was presented at the fourth International Surface Engineering Congress and Exposition held August 1–3, 2005 in St. Paul, MN.     

电镀cBN砂轮高速磨削高温合金的砂轮磨损研究

针对高速磨削的特点,采用电镀cBN砂轮进行了120 m/s高速条件下磨削镍基高温合金GH4169时的砂轮磨损试验研究.随着工件材料去除体积的增加,采用复型技术跟踪了砂轮工作表面在不同磨损时期的形貌变化,并对磨削力的变化进行了分析.研究发现,随着工件材料去除体积的增加,磨削力呈现初期快速增加、随后平稳增加的变化趋势,并且...     

Assessment of vitrified CBN wheels for precision grinding

Methods of measuring topographical features of grinding wheels are reviewed. Each technique has advantages and limitations for resolution, measuring depth, ease of application, data analysis and interpretation. Results obtained vary according to the method and instrument employed. Advantages and difficulties experienced with different techniques are discussed. Different replication techniques and materials are compared and suggestions made. A set of parameters that describe the wheel and grain characteristics is defined. Experimental studies with grinding wheels having different structures are carried out in terms of observations and measurements of changes in wheel topography. Experimental results are analysed and discussed in relation to theoretical understanding of abrasive wear and loading.     

Study on the grinding of P/M high speed steel ASP60

Several studies involved in grinding the P/M high speed steel ASP60 were carried out. The influence of the grinding mode under different grinding conditions was investigated. The grinding process was described and identified by using grinding parameters such as dimensionless maximum grain depth of cut h_g, arc of contact l_c, equivalent chip thickness h_eq. The optimum grinding parameters for ASP60 are suggested.     

Fine grinding of silicon wafers

Silicon wafers are used for the production of most microchips. Various processes are needed to transfer a silicon crystal ingot into wafers. As one of such processes, surface grinding of silicon wafers has attracted attention among various investigators and a limited number of articles can be found in the literature. However, no published articles are available regarding fine grinding of silicon wafers. In this paper, the uniqueness and the special requirements of the silicon wafer fine grinding process are introduced first. Then some experimental results on the fine grinding of silicon wafers are presented and discussed. Tests on different grinding wheels demonstrate the importance of choosing the correct wheel and an illustration of the proper selection of process parameters is included. Also discussed are the effects of the nozzle position and the flow rate of the grinding coolant.     

Strategies for production of parts textured by grinding using patterned wheels

The functionalization of surfaces by introducing pre-engineered textures is a new requirement from industry. Surfaces more prone to promote micro-lubrication are being designed by engineers and incorporated into the components specification. The major challenge is to develop manufacturing methods able to produce these textures in a repeatable and economically viable way. The aim of this research work is to develop grinding strategies based on the method proposed in [1] for producing textured surfaces by grinding. The characteristics of the produced textures are measured and evaluated using new proposed parameters. The obtained results show the potential of this process solution for the production of micro pockets for hydrodynamic bearings application.     

微晶刚玉砂轮磨削钛合金TC17试验研究

使用大气孔与普通气孔两种微晶刚玉砂轮开展钛合金磨削试验,研究磨削参数与气孔尺寸对磨削工件表面完整性的影响。试验结果表明:砂轮转速27m/s,磨削深度10μm时,可获得较好的表面质量;同普通砂轮相比,大气孔微晶刚玉砂轮磨削钛合金工件的表面质量更好、微观组织变化和表面残余应力更小。大气孔砂轮具有较好的容屑、排屑、冷却能力,使磨削温度降低、磨削力减小,是获得较好表面完整性的主要原因。     

Micro grinding tool for manufacture of complex structures in brittle materials

This paper presents a novel micro shaft grinding tool with cylindrical tool tip diameter between 13 μm and 100 μm. The manufacturing of the tool itself is carried out on a prototype desktop machine. The shaping of the tool is accomplished by grinding the tool tip directly onto the cylindrical carbide tool shank. During tool grinding, the tool shank rotates in a micro spindle with air-lubricated bearings, leading to high concentricity and low run-out. The tool tip is electrically nickel plated with diamond grains. During first experimental tests of the tool, very low surface roughness values and sharp edges without burrs were achieved.     

Special wire guide for on-machine wire electrical discharge dressing of metal bonded grinding wheels

To improve accuracy in wire electrical discharge dressing (WEDD), special attention should be given to wire vibration. In this work, the use of a specially designed wire guide is proposed, which is responsible for both ensuring the stability of the wire and improving the efficiency of dielectric delivery to the dressing zone. For carrying out experiments with metal bonded diamond grinding wheels, a WEDD-device was designed, manufactured and integrated into a grinding machine. High erosion material removal rates and dressing accuracy were achieved, thus demonstrating the feasibility and efficient performance of this in situ dressing process.     

Simulation of plunge centerless grinding processes

Workpiece out-of-roundness is one of the most important problems in centerless grinding. Besides geometrical and kinematical effects, the dynamical behavior of the machine structure, the grinding and regulating wheel together with the support blade fundamentally influence the process stability and the workpiece accuracy. The paper presents a method for a numerical simulation of plunge centerless grinding processes in time domain. Under consideration of the geometrical conditions of the grinding gap and the dynamical compliance behavior of the grinding system the developed algorithm enables a quantitative determination of the workpiece out-of-roundness, the progression of grinding and reaction forces as well as the calculation of dynamical displacements.     

Automatic search for wheel position in flute grinding of cutting tools

The profile of helical flutes has a great influence on properties of cutting tools. This paper presents an automatic method of searching for a wheel position in flute grinding for a given shape of the helical flute and grinding wheel profile. The algorithm is based on the main loop and two subroutines. The first algorithm is dedicated to the simulation of the flute profile by splitting the grinding wheel into many thin disks. The second algorithm represents the numerical evaluation of the reached profile that results from previous grinding simulation. Finally, the experimental evaluation using particle swarm optimization is presented and obtained results discussed.     

高速试验列车车轮的工业试制

介绍了为生产270km／h运营速度的高速车轮，马钢进行的工业试验概况，试制中采用的压轧、热处理、机加工工艺要点，以及试制车轮的性能检测结果，结果显示，试制车轮基本满足技术条件要求。同时对进一步提高车轮质量提出了建议。