Cylindrical Grinding Machine Research Articles

Optimal design approach for eco-efficient machine tool bed

An optimal design approach of machine tool bed with the aim of obtaining an eco-efficient machine structure is studied. The suggested method includes three phases. The first is the layout design optimization of stiffener plates inside bed. In order to improve the design efficiency, a simplified design model called fiber model is suggested, and the layout of the stiffener plates inside bed is optimized by changing a 3-dimensional topology design optimization problem to a 2-dimensional problem. The second is the detailed sizing optimization of stiffener plates and supporting blocks under the structure based on the initial optimal model resulted from phase one. Finally, a topology design optimization process is implemented to obtain a reasonable distribution of manufacturing holes in bed structure. By considering the manufacturing requirement, an optimal bed structure is obtained. The validity of the suggested method is confirmed by a typical cylindrical grinding machine tool bed, and the result shows that the suggested method is effective, and the optimal structure has much better mechanical and economical performance by comparing with the original structures.

Research of Vibrations of a System with in Series Connected Elastic Elements Joining a Mass with a Support

Theoretical analysis of vibrations of a system in which the mass is connected with the support in series of more than one elastic element had shown that there is possibility to provoke additional resonances. Condition of it is change of damping values of the system near the supposed resonance frequency defined calculations. Feed mechanism of cylindrical grinding machine of older design was researched from that point of view. The mechanism consists of chain of elastic elements in series connecting the wheelhead with the bed of machine. Large friction forces exist in the chains of elements and in the wheelhead ways. Analysis results are presented in the paper.

Fault diagnosis of cylindrical grinding machine

Based on experiment modal analysis (EMA) and operation modal analysis (OMA), the dynamic characteristics of cylindrical grinding machine were measured and provided a basis for further failure analysis. The influences of grinding parameters on dynamic characteristics were studied by analyzing the diagnostic signals extracted from racing and grinding experiments. The significant frequency of 38 Hz related to grinding wheel spindle speed of 2 307 r/min showed that the wheel spindle system was in a state of imbalance. And wheel rotating frequency of 38.45 Hz in grinding process was close to the first natural frequency of 38 Hz, which resulted in resonance. Moreover, the main excitation at 147 Hz in grinding process together with resonance led to the deterioration of workpiece. Roundness measurement of workpiece shows good agreement with the vibration responses obtained from dynamic experiments. The fault diagnosis method was also applicable to similar machining systems.

E18 円筒研削盤用熱変位測定装置の開発 : 砥石軸回転に伴う熱変位測定法の検討(OS1 最新工作機械(4))

E18 円筒研削盤用熱変位測定装置の開発 : 砥石軸回転に伴う熱変位測定法の検討(OS1 最新工作機械(4))

On-machine wire electrical discharge dressing (WEDD) of metal-bonded grinding wheels

Metal-bonded diamond wheels, due to its strong grain retention and thermal conductivity properties, are generally used for grinding difficult-to-cut materials, such as high-performance ceramics. On the other hand, the poor dressability of this type of bond limits its application. This study aims to evaluate the use of a wire electrical discharge machining (EDM) principle for truing and dressing metal-bonded grinding wheels. Through the EDM process, the electrically conductive grinding bond is eroded, so that grain protrusion can be generated. For evaluating this dressing process, a wire electrical discharge dressing unit was designed, manufactured, and integrated into a universal cylindrical grinding machine. The dressing process is carried out using the grinding oil also as dielectric fluid. High material removal rates were achieved. Cylindrical plunge grinding tests on silicon nitride workpieces indicated that in comparison to conventionally dressed wheels, smaller cutting forces and wheel wear are achieved by using EDM-dressed grinding wheels.

S1101-1-5 浸炭歯車の加工と性能に関する基礎研究 : 面圧強さに及ぼす鏡面仕上げの効果(伝動装置の基礎と応用セッション1)

In order to improve the load-carrying capacity of case-carburized gears, the effect of mirror polishing on surface fatigue of rolling-sliding contact was investigated. Case-carburized test rollers were finished by cylindrical grinding machine after the heat treatment. The ground surface of test rollers was finished by hand finishing with the abrasive paper and the buff. Next, the surface durability of test rollers was examined by using a 2-roller-type fatigue testing machine. For test rollers with the mirror polished surface, the following results are obtained : The rise of surface temperature during running is low. The number of pits decreases. The pitting fatigue life is longer under the heavy load conditions. The value of the endurance limit of the surface durability becomes higher. From these results, it is found that the tooth surface should be finished as smooth as possible to obtain the higher load-carrying capacity of case-carburized gears.

Technique for measuring the system and contact stiffness on a cylindrical grinding machine

Technique for measuring the system and contact stiffness on a cylindrical grinding machine

Thermal error evaluation and modelling of a CNC cylindrical grinding machine

With the relentless quest for improved performance driving ever tighter tolerances for manufacturing, machine tools are sometimes unable to meet the desired requirements. One option to improve the tolerances of machine tools is to compensate for their errors. Among all possible sources of machine tool error, thermally induced errors are, in general for newer machines, the most important. The present work demonstrates the evaluation and modelling of the behaviour of the thermal errors of a CNC cylindrical grinding machine during its warm-up period.

A Neural Network and Fuzzy-Based Methodology for the Prediction of Work Roll Surface Roughness in a Grinding Process

Grinding is a complex machining process with a lot of interactive parameters, which depend upon the grinding type and requirements of products. Surface roughness is a widely used index of product quality and in most cases it is considered as a technical requirement for mechanical product. In this paper, a neural network and fuzzy-based methodology are developed for predicting the surface roughness in a grinding process for work rolls used in cold rolling. This methodology predicts the most likely estimates of surface roughness along with lower and upper estimates using fuzzy numbers. The network model is trained using back-propagation algorithms. The initial training and testing dataset is identified on the basis of effect of a factor. The best possible network is chosen, with learning rate, number of neurons in hidden layer and error goals being decided automatically. A computer code was written in “C” language. The training and testing data are collected from carefully designed experiments. The validation of the methodology is carried out in a traverse cylindrical grinding machine in the Salem Steel Plant situated at Salem, India. The visual depiction of the training, testing and testing is presented. The validation of the methodology is carried out for grinding of alloy steel using a black carbide silicon grinding wheel. It is observed that the present methodology is able to make accurate predictions of surface roughness by utilizing small-sized training and testing datasets.

Process monitoring in non-circular grinding with optical sensor

Cylindrical grinding machines are increasingly used to produce workpieces with non-circular contours. This means that new demands are made on process monitoring and in-process measurements due to these non-circular contours. A new optical sensor system was integrated into such a grinding machine, making it possible to take measurements for quality assurance, optimisation of the grinding process and reduction of setting-up and machining time.

Synthetically Modeling of Thermal Error and Grinding Force Induced Error on a Precision NC Cylindrical Grinding Machine

Thermal errors and force-induced errors are two most significant sources of the NC grinding machine inaccuracy. And error compensation technique is an effective way to improve the manufacturing accuracy of the NC machine tools. Effective compensation relies on an accurate error model that can predict the errors exactly during machining. In this paper, a PSO–BP neural network modeling technique has been developed to build the model of the dynamic and highly nonlinear thermal errors and grinding force induced errors. The PSO–BP neural network modeling technique not only enhances the prediction accuracy of the model but also reduces the training time of the neural networks. The radial error of a grinding machine has been reduced from 27 to 8μmafter compensating its thermal error and force-induced error in this paper.

Improvement of Machining Accuracy in Micro Cylindrical Traverse Grinding

The elastic deformation of workpiece acted by grinding force is so large as to make the low machining efficiency and accuracy in the cylindrical grinding of micro parts of which the stiffness is extremely small because of their small diameter. In this study, the perpendicular axis type cylindrical traverse grinding is proposed for the manufacture of micro parts, and the undeformed chip shape in the grinding process is investigated comparing with that in the parallel axis type traverse grinding using generally for manufacture of over small-sized parts. The surface finish and the form accuracy of workpiece by the perpendicular axis type grinding are finer than those by the parallel axis type grinding with the developed micro cylindrical grinding machine.

Development of a Novel Vertical CNC Multiple-Function Integrated Grinding Machine

The importance of precision grinding processes is continually increasing in a wide range of machine industry. In particular, the demands for cylindrical and internal grinding processes with higher accuracy and higher productivity than ever before have recently increased in the machine tool and automotive industries. Within grinding machine context, the conventional cylindrical and internal grinding machine of horizontal spindle type has been in the leading position. Nevertheless, such grinding machines of horizontal type have not necessarily the most suitable structure to achieve higher accuracy and higher productivity. In order to meet such industrial requirements, it is necessary to develop a machine tool based on a new design concept. However, only few studies on an innovative grinding machine have been performed so far. Therefore, in this study, a development methodology for machine tool is proposed to realize an innovative grinding machine. Then a vertical CNC multiple-function integrated grinding machine was developed by the proposed methodology. The results of actual machining tests confirmed that the grinding machine has a remarkable performance.

Control System Configuration for Grinding Machine with Two Moving Axes and One Circumrotating Axis Ganged Function

By applying NC system with three axes ganged function to M1432 universal cylindrical grinding machine, a NC grinding machine with two moving axes and one circumrotating axis ganged function is designed and developed. Besides two moving axes ganged function, this machine has a special function of driving the form wheel dresser to circumrotate around the Y axis. Ordinary grinding machine with two axes ganged function can’t machine complicated parts such as seaming roll with steep gradient groove. But a grinding machine with this special unction can do this by precisely dressing the form wheel with various aspheric curves. With the set-in PLC function of NUM1020 NC system and the correlative parameters to be respectively setup, the new machine can be used to machine some complicated parts such as seaming roll. The system receives machining process codes which is pretreated by computer firstly and dresses the form wheel in DNC mode, then machines parts with the form wheel later.

Development of New Device for Form-Grinding and Research on the Profile-Accuracy

The profile accuracy of the workpiece is mainly determined by the accuracy of abrasive wheel in the form-grinding process. Thus, the shaped wheel dressing becomes one of the key points in the form-grinding process. In order to grind the revolving curved surfaces grooves whose cross-sectional profiles are steep and smooth, a new NC dresser with three NC axes is developed by adding a swing axis on the basis of NC external cylindrical grinding machine. A wheel of any desired convex profile can be dressed when using the Diaform single-diamond dresser and the possible geometrical interference between the single-diamond dresser and wheel can be eliminated. By analyzing the influence of installation accuracy on the profile accuracy, a method of comprehensive error compensation is presented. The comprehensive errors can be diminished greatly to improve the profile accuracy by means of error compensation. It is proved in the experiments that the precision requirements of grinding the formed surfaces grooves can be met.

Continuous Optimal Infeed Control for Cylindrical Plunge Grinding, Part 2: Controller Design and Implementation

This is the second of two papers concerned with on-line optimization of cylindrical plunge grinding cycles with continuously varying infeed control. In the first paper [1], dynamic programming was applied to a simulation of the cylindrical grinding process in order to explore the characteristics of optimal grinding cycles. Optimal cycles were found to consist of distinct segments each with predominant constraints. An optimal control policy was formulated with the infeed rate within each segment determined according to the prevailing constraint. The present paper is concerned with the design of the controller and its implementation. The control system to implement the optimization policy is described together with provisions to enhance robustness to modeling uncertainty and measurement noise. Robustness provisions include model adaptation by parameter estimation from on-line measurements of size and power, and incorporation of safety margins in the optimization process. Problems associated with practical implementation of the control system, stemming from power limitations and wheel wear, are also discussed. The controller performance is demonstrated on an instrumented internal cylindrical grinding machine.

ELID-grinding of microtool and applications to fabrication of microcomponents

A desktop fabrication system has been developed for advanced production shops, as an advanced micro-mechanical fabrication tool for producing advanced microcomponents. In this study, we developed a cylindrical grinding machine that employs the ELID technique, for use as a microtool. We also carried out detailed investigation on the performance of the electrode turning method of the ELID system; a microcylindrical shaft and microangular shaft were ground by the cylindrical grinding machine employing the ELID technique. Good dimensional accuracy was achieved.

205 Surface Characteristics of ELID Ground Micro-tools

A desktop fabrication system has been developed for advanced production shops, as an advanced micro-mechanical fabrication tool for producing advanced microcomponents. In this study, we developed a cylindrical grinding machine that employs the ELID technique, for use as a microtool. We also carried out detailed investigation on the performance of the electrode turning method of the ELID system; a microcylindrical shaft and microangular shfat were ground by the cylindrical grinding machine employing the ELID technique. Good dimensional accuracy was achieved.

In-process measurement of topography change of grinding wheel by using hydrodynamic pressure

This paper deals with an in-process measurement method for topography change of a grinding wheel, which can apply to wet grinding. A pressure sensor is set beside a grinding wheel with a small gap. When grinding fluid is dragged into the gap, hydrodynamic pressure, which corresponds to the gap length and the topography, can be measured. This method is applied to a cylindrical grinding machine. No electromagnetic properties of a workpiece and a grinding wheel affect measured results. The pressure is decreased with the increase of the gap length when the grinding fluid is supplied in the tangential direction of the grinding wheel. Spectra of the pressure are measured with an FFT analyzer. Higher frequency components are increased with the progress of grinding because of turbulent flow. Loading and dulling of a grinding wheel can be detected by the proposed method as well as its wear.

Machining error compensation of external cylindrical grinding using thermally actuated rest

This paper describes a new machining error compensation system for cylindrical grinding machine. In order to compensate the thermal distortion as well as the mechanical compliance, the thermally actuated rest was developed without deteriorating any mechanical performance of the rest. In this paper, a modeling of workpiece supporting system that includes the workpiece itself and the rest compliance was suggested to compensate the errors. To find the optimal distances between supports, genetic algorithm was employed. The simulation result about workpiece cylindricity show that the machining accuracy can be significantly improved by controlling the supporting spot of the rests. Also the experiment using newly developed actuators show that thermal error was reduced by 57%.