scholarly journals Cylindricity error measurement and compensation in traverse grinding of low-stiffness shafts

Mechanik ◽  
2018 ◽  
Vol 91 (11) ◽  
pp. 970-972
Author(s):  
Jan Burek ◽  
Paweł Sułkowicz ◽  
Robert Babiarz
Keyword(s):  
Elastic Deformation ◽  
Force Measurement ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Error Measurement ◽  
Low Stiffness ◽  
Grinding Machine ◽  
Cylindricity Error ◽  
Traverse Grinding

This paper presents a system of measurement and compensation of cylindricity error in low-stiffness shafts grinding. A programme, that generates the path of a grinding wheel taking into account the elastic deformation of the shaft and grinding machine on the basis of the grinding force measurement was developed

Effect of Steady Rest in Cylindrical Traverse Grinding of Slender Workpiece

2020 ◽  
Author(s):  
Hidetaka Fujii ◽  
Takashi Onishi ◽  
Chinhu Lin ◽  
Moriaki Sakakura ◽  
Kazuhito Ohashi
Keyword(s):  
Elastic Deformation ◽  
Contact Point ◽  
Traverse Speed ◽  
Grinding Force ◽  
New Method ◽  
Beam Model ◽  
Shape Error ◽  
Form Error ◽  
Low Stiffness ◽  
Traverse Grinding

Abstract In the case of traverse grinding of a slender workpiece, the ground workpiece is easily deformed by the normal grinding force due to its low stiffness. To reduce the form error caused by the elastic deformation of the workpiece, a steady rest is widely used. Generally, a steady rest is set to push the ground area of the workpiece. However, the stepped shape error is generated at the contact point where a steady rest pushed the workpiece because the pushing force of a steady rest is decreased after the material of the contact point is removed. In this study, to reduce the stepped shape error of the ground workpiece, we proposed a new method to set a steady rest. In this method, the steady rest was set to push the area where was not ground. In addition, the traverse speed of the workpiece was adjusted to keep the elastic deformation of the workpiece constant. The suitable method to control the traverse speed was estimated by using a beam model that could simulate the elastic deformation of the workpiece during the grinding process. It was confirmed that the new method could improve the form accuracy of a slender workpiece through grinding experiments.

Study on the Shape Error in the Cylindrical Traverse Grinding of a Workpiece with High Aspect Ratio

2014 ◽  
Vol 1017 ◽  
pp. 78-81
Author(s):  
Takashi Onishi ◽  
Takuya Kodani ◽  
Kazuhito Ohashi ◽  
Moriaki Sakakura ◽  
Shinya Tsukamoto
Keyword(s):  
Aspect Ratio ◽  
Elastic Deformation ◽  
High Aspect Ratio ◽  
Grinding Force ◽  
Grinding Process ◽  
Shape Error ◽  
Shape Accuracy ◽  
Low Stiffness ◽  
Traverse Grinding ◽  
Main Factor

In cylindrical traverse grinding of a long workpiece with high aspect ratio, the shape accuracy of a workpiece worsens due to its low stiffness. In this study, the grinding force was measured during grinding process to calculate the elastic deformation of a workpiece caused by the normal grinding force. By comparing calculated elastic deformation with the measured shape error of ground workpiece, the cause for the shape error in case of grinding a long workpiece was investigated experimentally. From experimental results, it is confirmed that the main factor of the shape error of the long workpiece is its elastic deformation during grinding process.

scholarly journals Improvement of the Form Accuracy of a Slender Workpiece in Cylindrical Traverse Grinding

2019 ◽  
Vol 13 (6) ◽  
pp. 728-735
Author(s):  
Takashi Onishi ◽  
Teppei Takashima ◽  
Moriaki Sakakura ◽  
Koichi Sakamoto ◽  
Kazuhito Ohashi ◽  
...  
Keyword(s):  
Elastic Deformation ◽  
Cycle Time ◽  
Traverse Speed ◽  
Grinding Force ◽  
Wheel Speed ◽  
Grinding Wheel ◽  
Form Error ◽  
Form Accuracy ◽  
Peripheral Speed ◽  
Traverse Grinding

During the cylindrical traverse grinding of a slender workpiece, the ground workpiece is easily bent by the normal grinding force owing to its low stiffness. Therefore, it is difficult to finish the slender workpiece with high accuracy. To prevent the elastic deformation of a workpiece during the grinding process, a steady rest is generally used. However, considerable skill of the worker is required to use a steady rest. Therefore, we developed a new traverse grinding method without any steady rest. In this method, the elastic deformation of a workpiece was kept constant by controlling the traverse speed of the workpiece. At the middle of the ground workpiece, where the elastic deformation increased easily, the traverse speed was slowed down. However, this method had a longer grinding cycle time because the average traverse speed decreased compared to that of the conventional method. To shorten the cycle time, the peripheral speed of the grinding wheel was increased to decrease the normal grinding force. Basic grinding experiments were carried out under several grinding conditions by changing the peripheral speed of the wheel. From these grinding experiments, it was confirmed that the normal grinding force and the form error of the ground workpiece decreased as the peripheral wheel speed increased. By using results obtained from basic experiments, grinding experiments involving changes in the traverse speed were carried out at two peripheral wheel speeds. The grinding cycle time was reduced successfully by increasing the peripheral wheel speed without an increment in the form error of the ground workpiece. Furthermore, a form error was observed at the end of the workpiece where the grinding wheel traveled away from the workpiece. The form error occurred because the normal grinding force decreased rapidly when the contact length between the workpiece and the wheel was decreased at the end of the workpiece. To prevent rapid changes in the normal grinding force, the traverse speed of the workpiece was increased at the end of the workpiece. By using this method, a ground workpiece with high form accuracy was obtained.

scholarly journals Traverse grinding of low-stiffness shafts with the use of a grinding wheel’s path correction

Mechanik ◽  
2018 ◽  
Vol 91 (8-9) ◽  
pp. 741-743
Author(s):  
Jan Burek ◽  
Paweł Sułkowicz ◽  
Robert Babiarz
Keyword(s):  
Force Measurement ◽  
Dimensional Accuracy ◽  
Grinding Force ◽  
Grinding Process ◽  
Shape Errors ◽  
Low Stiffness ◽  
Traverse Grinding

This paper presents a method of increasing the shape and dimensional accuracy of low-stiffness shafts manufactured in traverse grinding process. In order to achieve that, grinding force measurement was used. It allowed to calculate such a correction of a grinding wheel’s path, that allowed to decrease dimensional and shape errors of grinded workpieces.

Power Feedback Control in Cylindrical Traverse Grinding

2000 ◽  
Author(s):  
Rogelio L. Hecker ◽  
Steven Y. Liang
Keyword(s):  
Controller Design ◽  
Velocity Model ◽  
Input Power ◽  
Open Architecture ◽  
System Response ◽  
Grinding Wheel ◽  
Wide Range ◽  
Grinding Machine ◽  
Power Response ◽  
Traverse Grinding

Abstract This paper describes the design of a power controller in cylindrical traverse grinding (CTG), where the power consumed by the grinding wheel is controlled by regulation of the traverse velocity. A mathematical model relating the power to the traverse velocity was developed and quantified with machining data. The controller design was based on the power-velocity model developed and it was tuned to fulfill time response specifications including settling time and overshoot. An inner velocity loop was also designed and implemented inside the power close loop to guaranty a stable power response. The controller was implemented and tested on an open architecture cylindrical grinding machine. The results show that the controlled system response can be regulated to meet the requirements of time specifications, over a wide range of cutting depth and input power reference.

scholarly journals Improvement of Shape Error for Slender Parts in Cylindrical Traverse Grinding by Part-Deformation Modelling and Compensation

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1990
Author(s):  
Ivan Mendez ◽  
Jorge Alvarez ◽  
David Barrenetxea ◽  
Leire Godino
Keyword(s):  
Prediction Model ◽  
Experimental Validation ◽  
Grinding Force ◽  
Error Prediction ◽  
Grinding Wheel ◽  
Shape Error ◽  
Distributed Load ◽  
Force Monitoring ◽  
Traverse Grinding ◽  
Ground Part

Achieving geometrical accuracy in cylindrical traverse grinding for high-aspect slender parts is still a challenge due to the flexibility of the workpiece and, therefore, the resulting shape error. This causes a bottleneck in production due to the number of spark-out strokes that must be programmed to achieve the expected dimensional and geometrical tolerances. This study presents an experimental validation of a shape-error prediction model in which a distributed load, corresponding to the grinding wheel width, is included, and allows inclusion of the effect of steady rests. Headstock and tailstock stiffness must be considered and a procedure to obtain their values is presented. Validation of the model was performed both theoretically (by comparing with FEM results) and experimentally (by comparing with the deformation profile of the real workpiece shape), obtaining differences below 5%. Having determined the shape error by monitoring the normal grinding force, a solution was presented to correct it, based on a cross-motion of the grinding wheel during traverse strokes, thus decreasing non-productive spark-out strokes. Due to its simplicity (based on the shape-error prediction model and normal grinding force monitoring), this was easily automatable. The corrective compensation cycle gave promising results with a decrease of 77% in the shape error of the ground part, and improvement in geometrically measured parameters, such as cylindricity and straightness.

The X-C Linkage Grinding Force Model in Cam Grinding

2016 ◽  
Vol 693 ◽  
pp. 1187-1194
Author(s):  
Xiu Mei Chen ◽  
Qiu Shi Han ◽  
Bao Ying Peng ◽  
Qi Guang Li
Keyword(s):  
Theoretical Basis ◽  
Mechanical Analysis ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Force Model ◽  
Grinding Force Model ◽  
Cam Profile ◽  
Contour Accuracy ◽  
Servo Tracking ◽  
Grinding Machine

In cam grinding process, the grinding force changes with the change of cam contour, and its change leads to create the error of X-C linkage servo-tracking position, all of the factors reduce the cam the contour accuracy. To improve the accuracy of the cam profile, and research the effect of X-C axis servo tracking, the key vector of grinding force to the position is proposed, in which the factors have been considered including the grinding depth, curvature change, cam width, length and other effects. According to the mechanical analysis of cam and grinding wheel, a cam grinding XC-axis grinding force model is established. With the flat-bottomed follower cam as an example, the grinding force of X axis and C axis is calculated. The cam grinding experiment was conducted in the grinding machine, the tangential grinding force and normal grinding force were obtained and the model was verified. The grinding force mathematical model of X-C linkage provides the theoretical basis for the servo tracking position of X-C linkage grinding.

Improvement of Machining Accuracy in Micro Cylindrical Traverse Grinding

2007 ◽  
Vol 329 ◽  
pp. 39-44 ◽  
Author(s):  
Kazuhito Ohashi ◽  
Gui Fu He ◽  
Shinya Tsukamoto
Keyword(s):  
Small Diameter ◽  
Grinding Force ◽  
Machining Accuracy ◽  
Form Accuracy ◽  
Cylindrical Grinding ◽  
Micro Parts ◽  
Parallel Axis ◽  
Grinding Machine ◽  
Traverse Grinding ◽  
Perpendicular Axis

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.

Analysis of the Grinding Characteristics of β-Ga2O3 Crystal on Different Planes

2020 ◽  
Vol 19 (02) ◽  
pp. 235-248
Author(s):  
Hai Zhou ◽  
Jiahui Wei ◽  
Fang Song ◽  
Yongkang Li ◽  
Chuanjin Huang ◽  
...  
Keyword(s):  
Specific Energy ◽  
Grinding Force ◽  
Surface Grinding ◽  
Grinding Wheel ◽  
Experimental Conditions ◽  
Grinding Force Ratio ◽  
Force Ratio ◽  
Grinding Conditions ◽  
Grinding Machine

The (010) and (100) planes of a [Formula: see text]-Ga2O3 crystal were subjected to precision grinding tests with a resin bond diamond grinding wheel on a precision surface grinding machine. The grinding characteristics and surface grinding quality of the planes of the [Formula: see text]-Ga2O3 crystal were analyzed on the basis of grinding force, grinding force ratio, specific energy, and surface morphology. The (010) plane shows a larger grinding force and specific energy but a smaller grinding force ratio compared with the (100) plane. Under experimental conditions, the normal and tangential grinding forces of the (010) plane are 1.4–2.2 and 2.6–7.8 times that of the (100) plane, respectively. The specific energy of the (010) plane is 2.8–6.1 times that of the (100) plane, and the grinding force ratio of the (100) plane is 1.4–3.7 times that of the (010) plane. Under the same grinding conditions, the material removal methods for the two planes are evidently different. The (010) plane is mainly removed by brittle fracture and accompanied by a minimal broken area, whereas the (100) plane is mainly removed by cleavage layering and exhibits numerous block cleavage. The (100) plane is the strong cleavage surface, and the (100) plane demonstrates a higher surface roughness than the (010) plane under the same grinding conditions.

Experimental Verification of Effect of Grinding Fluid Excited by Ultrasonic Vibration

2012 ◽  
Vol 523-524 ◽  
pp. 197-202 ◽  
Author(s):  
Jun Ishimatsu ◽  
Hiromi Isobe ◽  
Keisuke Hara
Keyword(s):  
Surface Roughness ◽  
Resonant Frequency ◽  
Ultrasonic Vibration ◽  
Experimental Verification ◽  
Grinding Force ◽  
Vibration Energy ◽  
Grinding Wheel ◽  
Grinding Fluid ◽  
Alloy Tool ◽  
Grinding Machine

The grinding performance is strongly affected by grain condition. Especially loading directly raises the grinding force, reduces tool life and deteriorates accuracy of machining. In this study, ultrasonic exciter which applies vibration energy on grinding fluid was developed. The resonant frequency of 28kHz. The exciter is set between the fluid supplying nozzle and grinding wheel. The discharging grinding fluid from the nozzle is supplied to grinding wheel between the teeth of comb-shape horn. The performance is verified on surface grinding machine with vitrified WA grinding wheel. It was experimentally demonstrated that the excited grinding fluid prevented the loading and improved the surface roughness even for grinding of aluminum. And also improvement of surface roughness was recognized on alloy tool steel.

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