Cylindrical Grinding Machine Research Articles

Forces during Grinding Operation and its Relation to the Dressing Cycle

While grinding with CNC cylindrical grinding machines, there are many factors that determine the precision and accuracy of the finished product. These may include dimensional accuracy, surface roughness, circularity (roundness), cylindricity, etc. But all these factors pertain to the work. The condition of the tool, in this case, the cutting edges of the grinding wheel, also greatly influence the profile and precision of the work. So, in order to maintain the precision of the work, there is a need to repeatedly and regularly maintain the cutting edges in a good cutting condition, by the process of dressing. In other words, when the swarf gets adhered to the grinding wheel, the abrasive particles can no longer perform machining with the same efficiency, due to increase in contact surface area between the abrasive particles and the work. This dissertation describes a technique that can be adopted to continuously monitor the grinding forces generated during the grinding operation, by using an in-process 2-dimensional piezoelectric force sensor, which can simultaneously measure the force and break it down into its two force components. The force sensor not only calculates the force generated, but also quantifies the force variation. By analyzing the variation in the radial and tangential force components individually, and by conducting Fourier analysis on the observed data, it is found that deterioration of the grinding wheel and the dress pattern can be continuously monitored and controlled.

Kinematical design of a precision cylindrical grinder with volumetric error modelling and sensitivity analysis

Volumetric accuracy is one among several factors used to assess the quality and performance of a machine tool. Besides its use for assessing the performance of machine tool, the estimation of volumetric accuracy of a machine tool can also be used for compensation of volumetric errors or to study the influence of individual errors on the accuracy of machine tool. In this work, a kinematic model is developed for a cylindrical grinding machine tool to predict the volumetric accuracy of the machine and is experimentally validated. The developed model is used to analyse the influence of geometric and kinematic errors on the volumetric accuracy of the machine tool using a differential sensitivity analysis approach. On the basis of this analysis, critical geometric and kinematic errors and related functional elements in the machine tool assembly are identified. Suitable modifications in terms of design and assembly practices for those machine tool elements are proposed in order to improve the accuracy of the machine.

Kinematical design of a precision cylindrical grinder with volumetric error modelling and sensitivity analysis

Volumetric accuracy is one among several factors used to assess the quality and performance of a machine tool. Besides its use for assessing the performance of machine tool, the estimation of volumetric accuracy of a machine tool can also be used for compensation of volumetric errors or to study the influence of individual errors on the accuracy of machine tool. In this work, a kinematic model is developed for a cylindrical grinding machine tool to predict the volumetric accuracy of the machine and is experimentally validated. The developed model is used to analyse the influence of geometric and kinematic errors on the volumetric accuracy of the machine tool using a differential sensitivity analysis approach. On the basis of this analysis, critical geometric and kinematic errors and related functional elements in the machine tool assembly are identified. Suitable modifications in terms of design and assembly practices for those machine tool elements are proposed in order to improve the accuracy of the machine.

Badania wpływu warunków obróbki na przebieg procesu szlifowania wgłębnego stopów tytanu na szlifierce kłowej do wałków

Badania wpływu warunków obróbki na przebieg procesu szlifowania wgłębnego stopów tytanu na szlifierce kłowej do wałków

Szlifowanie brązu krzemowego BK31 na szlifierce kłowej do wałków

Szlifowanie brązu krzemowego BK31 na szlifierce kłowej do wałków

Analysis of service properties of cylindrically ground surfaces, using standard ISO 25178-2:2012 surface texture parameters

<p class="R-AbstractKeywords"><span lang="EN-US">At present surface roughness is one of the main indications of component quality. During the operation mainly the outer layer of the component is exposed to external action, and depending on the roughness structure conclusions can be drawn about the service properties of the surface. Because cylindrical grinding today is rather widely used and precise method of treatment of bodies of revolution in the field of mechanical engineering the given paper pays attention to the surfaces treated on cylindrical grinding machines, and more exactly to their roughness, determining the possible use of the given surfaces. For the analyses of the roughness parameters the ISO standard ISO 25178-2:2012”Geometrical product specifications (GPS) — Surface texture: Areal — Part 2: Terms, definitions and surface texture parameters” was used, in which there were determined the texture parameters of the surface. Contrary to other standards, such as ISO 4287, ISO 13565 the new standard allowed to assess real surface properties, since in the given case the surface is being viewed in three-dimension space. During the research three cylindrically ground samples treated at different cutting conditions were chosen. By the help of modern measuring equipment Taylor Hobson Talysurf Intra 50 the topography of the given samples was taken in order to obtain and compare the roughness parameters and for the purpose of setting relation between the cutting regime and roughness parameters, and determining mathematical model of cylindrically ground samples. As a result of research it was stated that the given type of surfaces is characterized by irregular roughness, that is location of micro-peaks regarding their height and shape are irregular and also the correlation function of cylindrically ground surfaces is rapidly diminishing, but the density distribution of ordinates is close to normal. Based on the above feature of surface roughness such service properties as wear resistance, retention of lubricants and coatings (adhesion) and provision of required contact area were determined.</span></p>

Quick On-Machine Measurement of Ground Surface Finish Available for Mass Production Cylindrical Grinding Processes

In mass production cylindrical grinding operations, the ground surface finish has never been measured in each grinding cycles because existing surface roughness testers take a relatively long time to measure surface finishes, and the introduction of a surface roughness tester in each grinding cycle would affect mass production processes. Therefore, the surface finish of all parts manufactured in a production lot is generally evaluated based on the measured results of only few parts by sampling checks. We have proposed a unique quick technique for measuring surface roughness. It uses electromotive force based on the slight frictional heat to evaluate the surface finish of cylindrical workpieces rotating on cylindrical grinding machines, and it can do this in a split second just after each grinding cycle, so it does not hamper mass production grinding processes. The proposed quick measurement system can capture the variations in surface finish in a set of repeated cylindrical grinding cycles without dressing. The possibility of accurate judging dressing time by using the quick measurement system in mass production grinding processes is shown experimentally.

CNC Cylindrical Grinding Machine Reliability Analysis and Optimization

CNC cylindrical grinding machine reliability is an important performance indicators, the level of reliability will directly affect the use of CNC cylindrical grinding machine. Reliability of the traditional classification method is not clear, standards are not uniform, the paper application taxonomy for 12 CNC grinding machines from September 2012 to July 2014 for two years more than 600 pieces complete failure and repair data for statistical analysis to identify a greater impact on the overall reliability of the fault location and cause of the malfunction. According to the probability of occurrence of each failure mode, the severity of harm's comprehensive evaluation of the degree of fault of each site, identify the weak links of the whole system. As a result, the reliability of CNC cylindrical grinding machine will be greatly improved.

Modeling and experimental analysis of wheel-work interface in the cylindrical plunge grinding process

This paper presents a study of grinding wheel-workpiece interference in external cylindrical plunge grinding processes. This is to study the effect of workpiece surface memory on the workpiece roundness error after grinding. The study has been carried out theoretically on a model simulating cylindrical grinding process. The model takes contact stiffness, grinding wheel and workpiece wear into consideration. The proposed model was sued to predict the normal grinding forces in cylindrical grinding as a function of the previous height and number of waves of the initial profile.The new model has been validated by conducting experiments on a cylindrical grinding machine. Results indicate that the proposed model shows a good agreement with the experimental data obtained.The results of experiments indicate that the proposed modeling method is both feasible and reliable. The results showed that the theoretical model was effective studying the output of cylindrical grinding process. Normal grinding force, vibration level, and roundness error in cylindrical plunge grinding processes are dependent on the workpiece surface memory. Keywords: Plunge Grinding, Modeling, Roundness Error, Surface Memory.

Design of MK1432/H CNC Precision Cylindrical Grinding Machine

MK1432/H CNC precision cylindrical grinding machine is suitable for precision grinding IT6 to IT5 cylindrical or conical revolving workpiece, the table of the rail bed for the paste with plastic rail, the first holder of the rotating dial tone from the motor frequency speed, with Germany's Siemens 810D CNC two-axis system, built-in PLC, liquid crystal display. Servo motor is 1FK6 series; configure automatic measuring instrument line detection, automatic grinding work to achieve closed-loop cycle, ensuring high machining dimensional accuracy. Machine bed using a large round hole, fin-shaped reinforcement plates, Bench points up and down the table, you can grinding conical, bed and table in the guide rail for the laminating, the friction coefficient is small, table driven by a servo motor directly to the Deputy move the ball bar, smooth and reliable movement. Mainly used in automobile, motorcycle parts factory and other machinery manufacturing industry, for the grinding disc type, short axis, and taper shank type etc. parts.

A Study on Modal Parameters of Cylindrical Grinding Machine Structure through Experimental Test and FEM

Machine tool vibrations have great impact on machining process. Dynamic parameters such as the modal frequencies and damping constant of their components are the essential technical information required in engineering analysis and design. In addition, this information is needed for numerical simulations and finite element modeling to predict the response of the structures to a variety of dynamic loadings. In this work, experimental modal testing of a cylindrical grinding machine has been performed to obtain the mode shapes and modal frequencies. A Fast Fourier Transform (FFT) Analyzer, Pulse lab shop was used to obtain the Frequency Response Functions (FRF) and subsequent extraction of modal data was performed using Me’scope modal analysis software. These modal parameters were then checked using finite element analysis software, Ansys which were found to comply with the experimental results

S112033 火砕流堆積物を用いた歯面仕上げ法の開発に関する基礎研究 : 浸炭焼入れ鋼の面圧強さに及ぼす表面性状の影響([S112-03]伝動装置の基礎と応用(3))

In order to prevent environmental pollution in the manufacturing process and to obtain high load-carrying capacity of the power transmission gears, the tooth surface-finishing methods using volcanic-ashes were investigated. First, case-carburized test rollers were finished by cylindrical grinding machine. Secondly, the ground surfaces were finished by using volcanic-ashes. Third, the influence of surface texture on surface durability of test rollers was examined using a 2-roller-type fatigue testing machine. For test rollers with finished surface, the following results are obtained under the heavy load conditions: The surface temperature occurred by friction is low. During running, the amount of wear and the number of pits decrease. From these considerations, it is found that the surface finished by use of volcanic-ashes containing various chemical compositions is smoother than ground surface. Furthermore, in the case of the alloy steel of the same quality and same process of case-carburizing, surface durability of case-carburized gears is improved by using volcanic-ashes.

Abrasion Monitoring and Automatic Chatter Detection in Cylindrical Plunge Grinding

Using conventional grinding wheels, wheel-sided chatter vibration is one of the limiting factors in terms of productivity and surface fin-ish. Initial vibration related to the dynamic behavior of the machine tool copy on the grinding wheel and its amplitude amplifies by abra-sion. To ensure high workpiece quality many expensive truing cycles are needed. In this context, we suggest a new set-up for the auto-matic chatter detection and elimination for external cylindrical grinding machines, reducing not only the high amount of true running cycles, but also improving the efficiency. In order to suppress the generation of the waviness on the grinding wheel the effect has to be identified during an early stage of its development. Therefore, a grinding machine is equipped with different types of sensors, i.e., eddy current, force, acoustic emission, acceleration sensors, and a tactile probe. Experimental results show, that exclusively measuring the displacement at the workpiece is sufficient for online computing wheel's waviness. Based on a model of the grinding process the other redundant sensors are used for validation. In addition, a robust online chatter detector based on the wavelet transformation is developed recognizing an instable grinding process. This model-based detection and estimation of waviness delivers solid results, it should be used for suppression of chatter in further work.

Structural and Shaping Design of Centerless Cylindrical Grinding Machine Based on CAD

In this paper, according to the requirements of the topic, through the large market research and a series of calculation, I design the requirements of the grinding wheel frame and the spindle. In combination with relevant patent reform on the basis of grinding machine, The guide part of the drive system, micro feeding and automatic feeding mechanism is analyzed and design calculation, so that the machine can greatly reduce the labor intensity of workers and improve the processing accuracy. On this base of the design, I design and select the suitable rail to guarantee the processing precision and the wheel frame seat movement accuracy by using the calculated data and shape dimensions. At last, I design structural and shaping of the centerless cylindrical grinding machine.

The Design Study of High-Speed Cylindrical Grinding Machine Transmission System

In mechanical processing, according to the requirements of components’ high surface quality, this paper makes a structure design of high-speed cylindrical grinding machine transmission system. Such structure is mainly used in high-speed grinding and powerful grinding, so as to improve the grinding efficiency. The design provides a certain basis for the further research of grinding machine structure.

Determining the optimum process parameter for grinding operations using robust process

We applied combined response surface methodology (RSM) and Taguchi methodology (TM) to determine optimum parameters for minimum surface roughness (Ra) and vibration (Vb) in external cylindrical grinding. First, an experiment was conducted in a CNC cylindrical grinding machine. The TM using L27 orthogonal array was applied to the design of the experiment. The three input parameters were workpiece revolution, feed rate and depth of cut; the outputs were vibrations and surface roughness. Second, to minimize wheel vibration and surface roughness, two optimized models were developed using computer-aided single-objective optimization. The experimental and statistical results revealed that the most significant grinding parameter for surface roughness and vibration is workpiece revolution followed by the depth of cut. The predicted values and measured values were fairly close, which indicates (RRa2=94.99 and RVb2=92.73) that the developed models can be effectively used to predict surface roughness and vibration in the grinding. The established model for determination of optimal operating conditions shows that a hybrid approach can lead to success of a robust process.

The Characteristics of High-Speed Cylindrical Grinding of Silicon Carbide and its Influence on the Surface Layer

There has been increased interest in the use of advanced ceramic materials such as silicon carbide in the recent past, due to its unique physical and mechanical properties. However, the increase of the machining rate relies on the understanding of material removal mechanism on the microstructural scale and the relationship between the grinding characteristics and formation of surface/subsurface machining-induced damage. In this paper, grinding characteristics and surface integrity of SiC ground with diamond wheel on cylindrical grinding machine have been investigated. The grinding chip and the ground surface damage have been studied with scanning electron microscope (SEM). In particular the residual stress distribution has been analyzed by a single exposure technique d - sin2 (Ψ) method with the aid of powder X-ray diffractometer.

An intelligent system approach for surface roughness and vibrations prediction in cylindrical grinding

This work aims to develop an adaptive network-based fuzzy inference system (ANFIS) for surface roughness and vibration prediction in cylindrical grinding. The system uses a piezoelectric accelerometer to generate a signal related to grinding features and surface roughness. To accomplish such a goal, an experimental study was carried out and consisted of 27 runs in a cylindrical grinding machine operating with an aluminium oxide grinding wheel and AISI 8620 steel workpiece. The workpiece speed, feed rate and depth of cut were used as an input to ANFIS, which in turn outputs surface roughness (Ra) and vibration (az ). Different neuro-fuzzy parameters were adopted during the training process of the system in order to improve online monitoring and prediction. Experimental validation runs were conducted to compare the measured surface roughness values with the values predicted online. The comparison shows that the gauss-shaped membership function achieved an online prediction accuracy of 99%.

Vibration in Traverse Cut Cylindrical Grinding - Experiments and Analysis

Good surface finish is one of the important demands from the outputs of a cylindrical grinding machine. Also it is expected that dimensional accuracy, including accuracy in roundness, is fine in traverse cut cylindrical grinding. Now, like any other machine tool, cylindrical grinding machines also do vibrate, and vibration will affect accuracy and surface finish of the parts produced in grinding. The analysis of vibration in cylindrical grinding is then very much important. In the present study some aspects of vibration – behavior of cylindrical grinding machine have been experimented and analyzed. The process parameters have been varied and vibration signals have been measured in different directions by positioning an accelerometer at tail stock of the machine. The data have been analyzed through various statistical techniques to identify and predict vibration at given combinations of process parameters. The results and analysis of data give useful idea about dynamic performance of cylindrical grinding machine in traverse cut cylindrical grinding operation.

Development of Measurement Device for Thermal Displacement in Cylindrical Grinding Machines (Study on Measurement Method for Thermal Displacement with Rotation of Wheel Spindle)

Cylindrical grinding machines are typical machine tools for the final finishing process which produce high accurate and value-added products. However the universal method of measurement and evaluation for their thermal displacement has not been established. Therefore, in this study, we propose a measurement and evaluation method for the thermal displacement of the cylindrical grinding machines with rotation of the wheel spindle and make a device on an experimental basis based on the proposition and examine their validity. As the result of this study, it is made clear that the method proposed by us can measure and evaluate effectively and simultaneously 5 thermal displacements of the cylindrical grinding machines, that is, 3 translational deviations and 2 angular deviations.