Grinding Wheel Profile Research Articles

Effect of the Axial Profile of a Ceramic Grinding Wheel on Selected Roughness Parameters of Shaped Surfaces Obtained in the Grinding Process with a Dual-Tool Grinding Head.

The use of CNC equipment that integrates several machining operations eliminates downtime due to changes in setup and clamping of workpieces in more than one machining device. A review of CNC equipment and tools known from the literature and from manufacturers' offerings indicates that new technical solutions are being developed to integrate two or more technological operations. However, these examples have numerous limitations and are mostly not suitable for machining surfaces with complex shapes. An example of such solutions is the use of a dual-tool grinding head, which integrates the process of rough grinding with a ceramic grinding wheel and finish grinding with a flexible grinding wheel. Unfortunately, it has the disadvantage of being limited by the angular shape of the ceramic grinding wheel, making it unable to adapt to the complex geometries of the shaped surfaces being ground. The need to overcome this limitation became the motivation for the research work described in this article. By means of experimental research, it was verified what effect the radial outline on the periphery of a ceramic grinding wheel realized by rough grinding would have on the surface roughness parameters obtained in the process of grinding shaped surfaces. For this purpose, grinding processes using a ceramic wheel with a conical and radial outline were compared. The result of the study was a summary of the surface roughness parameters Sa, St, Sq, Spk, Str, and Sds obtained after two-stage machining (rough and finish grinding). The obtained analysis results showed that changing the axial outline of the ceramic grinding wheel makes it possible to significantly expand the range of applications of the dual-tool head without negatively affecting the quality of the machined surface. Thus, such an improvement will make it possible to increase the applicability of the head by grinding shaped surfaces with a radial profile of curvature.

Research on chip flute design of variable pitch variable helix end milling cutter based on manufacturability

In this paper, a design method of chip flute structure of variable pitch variable helix (double variable) end milling cutter based on manufacturability is presented, which aims to improve the dynamic balance and milling performance of the tool. The feasible region for grinding the chip flute of a double variable end milling cutter is obtained by solving the numerical model for the shape of the radial cross-section curve of the chip flute, along with the position and orientation of the grinding wheel. The multiple tool-walking grinding method is proposed to avoid the interference and edge cutting between the grinding wheel profile and the chip flute section, and the chip flute structure design criterion is obtained. The error between the grinding simulation results and the design target parameters is about 1 %, which verifies the effectiveness of the design criteria. With the double variable end milling cutter designed by this criterion, the milling vibration amplitude is reduced by about 21 %, and the average surface roughness of the workpiece is reduced by 9.872 μm. The chip flute structure design method proposed in this paper not only meets the manufacturing feasibility, but also effectively improves the milling performance of the tool. On the premise of considering manufacturability, the design method of chip flute as the optimization objective provides a new idea for tool structure design.

An optimized calculation method of the grinding wheel profile for the helical flute forming grinding

An optimized calculation method of the grinding wheel profile for the helical flute forming grinding

Trajectory planning of deep-cutting laser profiling of superabrasive profile grinding wheels

The low profiling efficiency is the key barrier to the industrial application of laser dressing technology for profile grinding wheels. In this paper, the trajectory planning method of deep-cutting laser profiling was proposed for the first time, the theoretical model of the energy distribution of the Gaussian laser beam on the surface of the profile grinding wheel was established, and the effect of this method on improving the profiling efficiency of superabrasive profile grinding wheel was systematically studied. Through comparative experiments, it was confirmed that the trajectory planning method could effectively improve the profiling efficiency of the V-shaped grinding wheel, and it was found that the smaller the tip angle, the greater the efficiency improvement. The change of grain size will lead to the change of grain removal method, which will affect the profiling efficiency of V-shaped grinding wheel, but it has little influence on the profiling accuracy. The V-tip arc radius of the diamond grinding wheel with a particle size of 20–180 μm after laser profiling could be controlled between 10 and 20 μm, which was difficult to achieve by mechanical or electrical dressing method. The trajectory planning method could also significantly improve the profiling efficiency of convex/concave arc-shaped grinding wheels, and the greater the arc radius or chord-to-diameter ratio of the grinding wheel, the greater the efficiency improvement. Even though convex/concave arc-shaped grinding wheels were the same size, their profiling efficiency and material removal efficiency were quite different. For grinding wheels with different arc radii or chord-to-diameter ratios, different process strategies should be selected during laser profiling to ensure a comprehensive balance between efficiency, accuracy and quality.

Grinding wheel profile design and temperature field analysis of the pinion for internal meshing gear with curve configuration

To further develop the performance testing and practical application of internal meshing gear with curve configuration, the grinding manufacturing method is proposed in this paper. Based on basic principle of internal meshing gear with curve configuration, Newton’s iterative method is used to derive the contact line condition equation during the process of form grinding. Then, the spatial coordinate transformation relationship of the pinion is established, and normal profile of the grinding wheel is derived. An improved transversal algorithm is proposed to analyze the tooth profile error after form grinding simulation, and the results verify the correctness of the designed grinding wheel. A meshing model with single tooth is established. The effects of different parameters on the grinding temperature field under dry and wet grinding conditions are simulated respectively, which will be helpful to the optimization and control of temperature in grinding process. The research results lay the essential theoretical foundation and engineering analysis for practical form grinding applications of the new internal gears. Further study on experimental analysis of grinding manufacturing process of the new tooth surfaces will be carried out.

Design for manufacturing of a spur gears profile modification based on the static transmission error for improving the dynamic behavior

This study presents a novel iterative algorithm for obtaining an improved profile modification for spur gears based on minimizing the peak-to-peak static transmission error. Two improved profile modifications, obtained with different initial constraints applied to the tooth profile, were calculated and characterized. The static behavior of the gears was analyzed using a finite element model, by which the modifications were compared considering the maximum contact pressure and peak-to-peak static transmission error. The dynamic behavior of the gears was analyzed using a lumped parameter model. The dynamic overload and the dynamic transmission error were evaluated under several working regimes. The grinding wheel profiles used to realize the proposed profile modifications and the total volume of material removed were calculated using a CAD model. The results showed that the proposed modifications lead to a significant improvement in the static and dynamic behavior of the transmission by reducing both the maximum dynamic overload and meshing noise. The profiles of the grinding wheel were found to be accurately represented by polynomial functions, thus a feasible manufacturing process can be obtained. The total volume of material removed was lower than that produced by commonly adopted profile modifications, thus reducing material waste and increasing the productivity of the manufacturing process compared to standard profile modifications.

Design and Manufacture of Power Skiving Cutter From Target Circular Spline Geometry

Abstract In this study, a novel design scheme for a power skiving cutter and its grinding wheel profile is proposed based on the geometry of a target circular spline (CS) workpiece. First, a generalized mathematical model of a target CS profile is expressed using a B-spline curve. Subsequently, the nominal cutting edge of the skiving cutter for generating an error-free CS is derived based on power skiving kinematics. In addition, the axial profile of the grinding wheel for generating the derived nominal cutting edge is resolved based on lengthwise-reciprocating grinding kinematics. The proposed design process for the skiving cutter and its grinding wheel is illustrated using numerical examples. The profile accuracy of the CS yielded by the designed nominal cutting edge is computed to validate the proposed design processes. Moreover, errors of the skived CS profile resulting from various resharpening depths by grinding back the stepped rake face of the skiving cutter are investigated. Finally, to effectively extend the tool life of the skiving cutter, a compensation rolling angle is introduced into the CS skiving process.

Technological aspects of grinding the side surfaces (relieving) of the teeth gear-cutting worm hobs

Contact line geometry at relieving of tooth flanks of gear cutting hobs and functional relations for calculation of relieving machine setting parameters for achieving the required accuracy of the tooth profile of the generating rack are determined. They include the setting angle of the grinding wheel axis and profiles of grinding wheel active surfaces for each of the tooth flanks. A method of calculating the single setting angle of the grinding wheel axis for both tooth flanks of the hob is developed.

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.

Application of Mathematical Morphology in Solving the Profile of Forming Grinding Wheel

In the development of modern tools, the flute (or profiling flute) after design optimization is often obtained by grooving with a forming grinding wheel. At present, the main method of reverse forming wheel profile is the analytical method, which needs to solve the contact line equation according to the contact conditions. It is difficult to solve the equation. The solution value is unstable, which leads to the design error of the grinding wheel profile. In order to solve this problem, this paper proposes a new algorithm, called the pixel matrix method for short. This method is based on the spiral motion envelope method and mathematical morphology. First, the cross-section of the flute is discretized into a point cloud, and then, the envelope motion is carried out in the grinding wheel coordinate system. Second, the point cloud of the grinding wheel radial section is collected and converted into a binary image of pixel points. Finally, the profile of the binary image is extracted by erosion and dilation. The optimized profile of the formed grinding wheel reaches the accuracy requirements of the design and processing in the actual machining verification. This method can accurately reverse the profile of the forming grinding wheel. The calculation process is intuitive, avoiding the solution of the contact line equation, and the solution value is stable. It provides a new way to reverse the profile of the machining tool for cylindrical spiral products.

Исследование взаимосвязи режущей способности инструмента с параметрами акустического сигнала в процессе профильного шлифования

Introduction. Modern mechanical engineering is closely connected with digital production management technologies, for which an important aspect is the collection of reliable information about the current state of the systems. Acoustic methods of current control of the tool cutting ability possess significant potential due to the possibility of continuously obtaining up-to-date data on the parameters of machining process. Profile grinding is one of the widespread methods of machining surfaces of complex configuration. The high importance of this method lies in the high degree of responsibility of shaped parts obtained with it. The wear parameter of profiled grinding wheels needs current control to the same extent as other types of cutting tools. At the same time, acoustic methods of research have not found wide application in relation to profile grinding. In view of this, the present work is aimed at studying the influence of the tool wear rate on the acoustic characteristics of grinding when using grinding wheels of different profiles. Purpose of work is to determine the acoustic parameters of profile grinding with application of planar grinding scheme as it wears out in comparison with analogical process with application of straight profile grinding wheel. As the basic methods of research an experiment is used to study the acoustic phenomena accompanying grinding with application of wheels of different profile. An analysis of the acoustic signal of grinding is carried out, as well as an analysis of the spectrum of its frequency composition. The frequencies of natural vibrations of grinding wheels of different profiles are investigated, its sound index is determined as a criterion for evaluating its characteristics. Acoustic characteristics of the grinding process with the use of grinding wheels of different profiles are compared. Regression analysis of acoustic data obtained as a result of the experiment is also used. Results and discussion. Spectrograms of frequencies of natural vibrations of the wheels under research, as well as a number of spectrograms of the acoustic signal accompanying the processing process for various technological conditions are received. As a result of comparing the obtained spectrograms, the informative frequencies of the grinding processes are determined. Mathematical models of sound level dependence on the value of periodic vertical feed St at depth t and processing time T are developed. It is established that the value of periodic vertical feed St at depth t has a greater influence on the acoustic index in comparison with the machining duration T. Practical significance and prospects of the results of the work lies in the possibility of increasing the efficiency of profile grinding processes due to the rational use of the tool availability.

Generating precise non-flat grinding wheel surfaces via CO2 laser ablation: Understanding the relationship between overlap rate and feed rate on composite materials

Non-flat structures are essential features in key mechanical functional surfaces such as aero-space engine blade tenons, screw rods and machine tool guide rails etc., which usually require profile grinding as the finishing process to meet demanding working requirements. However, the precise manufacturing of profile grinding wheels remains challenging as it is hard to remove the superhard materials within the grinding wheel in a controllable way. Dressing the target wheel by laser ablation appears promising, however, the interactions between the laser energy beam and target composite materials are quite complex, especially the combined behaviours among a serial of adjacent ablation tracks are hard to understand when concerning the ever-changing Overlap Rates (ORs) and feed rates in the ablation process. In this study, the nature of the laser beam and the characteristics of the beam energy distribution are analysed. The shapes for the laser ablation under various ORs and feed rates are theoretically analysed and experimentally validated. Based on the results, empirical prediction models regarding ablation depth, width, and topography changing with ORs and feed rates are established. Finally, the possibility of manufacturing profiled grinding wheels by controlling overlap and feed rates is studied. An attempt to generate precise non-flat structures (including stepped and curved surfaces) via ablation with a CO2 laser using the developed strategies is performed, and a smooth profile with a relative error of 2.2 % is achieved without any extra focal plane change manipulations. The work provides a novel strategy for the manufacturing of complex-profile grinding wheels.

Surface topography modeling and analysis of camshaft generated by swing grinding process

In conventional grinding (CG), camshafts with wide profiles suffer from poor quality and low efficiency because the large contact area between the grinding wheel and camshaft profile limits the diffusion of grinding temperature, leading to burning defects. Swing grinding (SG) can mitigate these problems as it involves a reciprocating motion along the axis of the grinding wheel; however, the lack of understanding of machined surface topography has restricted its application. Therefore, in this study, a surface topography prediction model was proposed that based on the distribution, shape, and trajectory of grains. The model was verified through experiments, and the mean error was 12% for Rax and 9% for Ray; the roughness along the grinding direction was Rax, and the roughness along the vertical grinding direction was Ray. Compared to CG, SG has a 3% lower Ray. The influence of the wheel speed and feed rate in SG is consistent with that in CG. Rax exhibited a periodic trend with an increase in the swing amplitude and a monotonically decreasing trend with an increase in the swing frequency. The variation trend of Ray with the swing amplitude was the same as that of Rax. Furthermore, Ray exhibited a nonlinear increasing trend with an increase in swing frequency.

Surface and subsurface microscopic characteristics in sapphire ultra-precision grinding

To investigate surface and subsurface microscopic characteristics, the ultra-precision grinding experiments of sapphire were carried out by the minimal parameter cycle method. The effects of grinding wheel grit sizes and grinding cycles number on surface and subsurface characteristics were investigated. It was confirmed that the full ductile damage-free surface with Sa10nm can be achieved, and the microscopic characteristics of rough grinding and ultra-precision grinding surfaces are different. The effect of abrasive particle size on surface roughness and grinding wheel profile wear was discussed. Moreover, the subsurface characteristics were surveyed through molten KOH corrosion, the subsurface marks and subsurface damage were observed. The subsurface damage was dominated by median cracks, it can be observed under the ductile surfaces.

Laser machining and compensation truing of small concave-arc bronze-bonded diamond grinding wheels

A laser can be effectively used as a “dressing pen” to dress super-abrasive forming grinding wheels. However, laser truing and sharpening methods are in their primary stages. Problems caused by poor dressing persist in the absence of a theoretical analysis of trimming, and there is no effective compensation algorithm to correct actual and theoretical deviations. A pulsed fibre laser was used to dress a small concave arc-profiled 230# bronze-bonded diamond grinding wheel in this study. The Canny-based sub-pixel edge detection algorithm was improved to effectively enhance the detection of circular edges. Experiments were performed on coarse laser dressing of profiling concave-arc wheels, and the regularity of the radius, angle and depth of the arc was investigated. An error analysis model for the laser profiling of small concave-arc grinding wheels was developed and used to determine the factors causing error and that the concave-arc grinding wheel produces a minimum roundness error of 34 μm under the considered experimental dressing conditions. A novel error compensation method for trimming was developed, the horizontal approximation compensation method (HACM). Compensated trimming experiments were performed with effective error compensation. The final trimming dimensional error was approximately 11.2 μm, and the roundness error was approximately 22.8 μm. The main external factors causing these errors were laser thermal effects and the burrs detected on the graphite plate.

Resin Bonded Diamond grinding wheels conditioning using SiC rotary dresser

Superabrasive grinding of advanced materials parts with complex geometry is a critical issue for aerospace or energy industry. Likewise, conditioning of superabrasive is a key process in order to obtain the most effective grinding. While from industrial point of view the conditioning parameters and dressers are designed from the experience, from scientific point of view the last works are focused on achieving guidelines for optimising conditioning process. In this sense, the present work is focussed on the conditioning process of diamond resin bonded grinding wheels. To this end, SiC rotary dressers of different hardness and applying down-cut and up-cut are tested in order to achieve the best conditions. On the one hand, the wheel surface is deeply analyse. A software is developed in order to analyse the grain pull out, the new abrasive grains and the size evolution and grain concentration during conditioning. On the other hand, the wheel geometry is also measured due to the importance of geometry loss during the conditioning process on profile grinding wheels. The results shown that down-cut conditions are more aggressive obtaining a better wheel surface recovery and the wheel geometry of the incidence edge is lost, requiring a subsequent truing process to obtain the wheel profile. Finally, it is noteworthy that the methodology developed for the analysis of the diamond resin bonded grinding wheels is suitable for all types of grinding wheels even rotary dressers.

On-machine precision truing of ultrathin arc-shaped diamond wheels for grinding aspherical microstructure arrays

Precision grinding with ultrathin arc-shaped diamond (UAD) grinding wheels provides a satisfactory solution for the fabrication of high-quality microstructures on tungsten carbide (WC) molds. However, ultrathin grinding wheels are difficult to be trued, due to the limited small grinding wheel profile. In this paper, an on-machine truing method for ultrathin arc-shaped diamond grinding wheels is proposed. First, a model of the three-axis linkage controlling truing for the diamond grinding wheel was introduced. Then, the effects of the setting and measurement errors of the grinding wheel on the profile radius were theoretically analyzed. A mathematical model of the error was developed. Furthermore, an aspherical microstructure array of tungsten carbide was ground by the trued diamond grinding wheel. The experimental results demonstrated that the expected arc radius of the grinding wheel could be achieved and the binderless tungsten carbide mold could be ground efficiently and precisely. The profile error of the grinding wheel (diameter of 23 mm, thickness of 0.38 mm) reached 8.5 μm. An aspherical microstructure array surface of tungsten carbide with a form accuracy of 15 μm was obtained by grinding with the trued diamond grinding wheel without additional compensation.

Modelling and experiment of gear hob tooth profile error for relief grinding

Gear hob is an important tool that is most used in gear processing. Hob accuracy directly exerts an overwhelming influence on the quality of the processed gear. Generally, the hob tooth profile accuracy is mainly determined by relief grinding process. Studies on tooth profile errors of gear hobs caused by severe friction and cutting with the high-speed rotation of the wheel during the form grinding machining of hobs are limited. Thus, a theoretical model of the tooth profile error prediction under different machining parameters was established based on the analysis of coupling influence of high temperature and high strain rate on gear hobs in the relief grinding process. The model was completed on the basis of the dynamic explicit integral finite element method of thermo-mechanical coupling. Through the prediction model, the influence of the grinding depth ap, feed speed Vw and grinding speed Vs on the tooth profile error can be analysed. In addition, an algorithm for accurately calculate the grinding wheel axial profile by combining instantaneous envelope theory and hob normal tooth profile was proposed. The hob relief grinding experiments were carried out using the proposed grinding wheel profile algorithm. The relative error of the prediction obtained by comparing the calculation results of the prediction model with the experimental results is within 10%. Results prove the validity of the prediction model. This finding is greatly important for optimising the accuracy of hob relief grinding.

Research on Motion Generation for Machining Involute Tooth Profile Surface Based on Analysis Method

Starting from the configuration characteristics of gear, the pose relationship between grinding wheel and involute tooth profile surface is clarified. Pose matrix of grinding wheel relative to involute tooth profile surface is established, and the necessary motion modules are obtained. A method for designing motion module combination for machining involute tooth profile surface is created, and module combinations are screened. An effective module combination and a reasonable schematic diagram of motion module combination are gived. The method adopted in this paper is beneficial to motion module design for machining involute tooth profile surface.

Investigation on cooling behavior of axially rotating heat pipe in profile grinding of turbine blade slots

During profile grinding of fir-tree blade slots, a key issue is usually the excessive heat caused by the complex contact zone. Most studies have focused on the cooling efficiency of the coolant; however only few have investigated the heat transfer potency of the grinding wheel matrix. In this study, a new cooling method that incorporates an axially rotating heat pipe (RHP) in the profile grinding wheel has been proposed. The cooling behavior of the new method was analyzed by both simulation and experimental grinding of titanium alloys. The temperature distributions along the RHP and the workpiece surface were monitored using embedded thermocouples. The effects of input heat flux, filling ratio and rotational speed on heat transfer performance were discussed. Comparative profile grinding experiments among RHP cooling, coolant cooling and no cooling demonstrated a great cooling advantage of RHP cooling with the lowest grinding temperature and better workpiece quality. Considering the research gaps of the previous studies, this work is not only deepens the understanding of the cooling behavior in the RHP during profile grinding of turbine blade slots, but also is helpful to provide guidance on the green machining of industrial products with complex profiles.