Improvement of the Form Accuracy Ground by a Slender Wheel in Internal Grinding

2020 ◽  
Author(s):  
Takashi Onishi ◽  
Yusuke Nakabayashi ◽  
Moriaki Sakakura ◽  
Go Ichiba ◽  
Kazuhito Ohashi
Keyword(s):  
Aspect Ratio ◽  
Elastic Deformation ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Deep Hole ◽  
Form Error ◽  
Form Accuracy ◽  
Internal Grinding ◽  
Inner Surface

Abstract In the case of internal grinding of a deep hole, the inner surface of the hole was ground by a slender grinding wheel that has a high aspect ratio. A slender grinding wheel is bent by the normal grinding force during the grinding process. Therefore, the form accuracy of the ground workpiece is decreased especially when the aspect ratio of a wheel is high. In our previous study, it was confirmed that the biggest factor that generated the form error of the workpiece was the elastic deformation owning to the normal grinding force. To reduce the form error of the ground workpiece, it is effective to expand the spark-out duration. However, the expansion of the spark-out duration leads to the low productivity. In this study, the form of the grinding wheel was modified by a diamond dresser to improve the form accuracy of the workpiece without expanding the spark-out duration. The modified form of a wheel was determined to compensate the form error of the workpiece generated by the elastic deformation of the grinding wheel. Thorough several grinding experiment, it was confirmed that the form accuracy of the ground workpiece was successfully improved by modifying the form of a slender grinding wheel without expanding the spark-out duration.

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.

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.

New Compensation Grinding of Axisymmetric Aspherical Lenses with High NA Value

2005 ◽  
Vol 291-292 ◽  
pp. 51-56
Author(s):  
Nobuhito Yoshihara ◽  
Tsunemoto Kuriyagawa
Keyword(s):  
Grinding Wheel ◽  
Grinding Process ◽  
Form Error ◽  
Cross Sectional ◽  
Form Accuracy ◽  
Optical Instruments ◽  
Grinding Method ◽  
Cross Sectional Profile ◽  
Aspherical Lenses ◽  
Sectional Profile

Aspherical parts are installed in various optical instruments. At present, a higher form accuracy is required for aspherical parts to improve the resolution of the optical instruments. To meet this demand, an arc envelope grinding method has been developed. In the arc envelope grinding process, a spherical shaped grinding wheel is used and the form error of the cross-sectional profile of the grinding wheel is transcribed to the workpiece profile. Therefore, the grinding wheel should be trued previously. However, the form error of the grinding wheel cannot be removed perfectly. To reduce the affect of the form error of the grinding wheel, compensation grinding must be carried out. In this work, the wheel path of a new compensation grinding method is proposed for a high NA value of the workpiece. Tests using the new compensation grinding method demonstrate the reduction in the form error of aspherical parts.

scholarly journals Study on the Effect of Grinding Pressure on Material Removal Behavior Performed on a Self-Designed Passive Grinding Simulator

2021 ◽  
Vol 11 (9) ◽  
pp. 4128
Author(s):  
Peng-Zhan Liu ◽  
Wen-Jun Zou ◽  
Jin Peng ◽  
Xu-Dong Song ◽  
Fu-Ren Xiao
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Service Life ◽  
Material Removal ◽  
Removal Rate ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Temperature ◽  
Grinding Efficiency

Passive grinding is a new rail grinding strategy. In this work, the influence of grinding pressure on the removal behaviors of rail material in passive grinding was investigated by using a self-designed passive grinding simulator. Meanwhile, the surface morphology of the rail and grinding wheel were observed, and the grinding force and temperature were measured during the experiment. Results show that the increase of grinding pressure leads to the rise of rail removal rate, i.e., grinding efficiency, surface roughness, residual stress, grinding force and grinding temperature. Inversely, the enhancement of grinding pressure and grinding force will reduce the grinding ratio, which indicates that service life of grinding wheel decreases. The debris presents dissimilar morphology under different grinding pressure, which reflects the distinction in grinding process. Therefore, for rail passive grinding, the appropriate grinding pressure should be selected to balance the grinding quality and the use of grinding wheel.

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.

Development of Three-Dimensional Dynamometer for Wafer Grinder

2010 ◽  
Vol 126-128 ◽  
pp. 361-366 ◽  
Author(s):  
Xiang Long Zhu ◽  
Ren Ke Kang ◽  
Yong Qing Wang ◽  
Dong Ming Guo
Keyword(s):  
Three Dimensional ◽  
High Sensitivity ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Performance Parameters ◽  
Grinding Forces ◽  
Grinding Method ◽  
Static Performance ◽  
Good Repeatability

Grinding forces during grinding silicon wafer have great influences on the accuracy, surface quality and grinding yield of the wafer. It is necessary to develop an accurate and reliable grinding dynamometer for measuring and monitoring the grinding process of the large and thin wafer. In this work, a new 3D (three-dimensional) grinding dynamometer using piezoelectric sensors is designed and developed, which is used for a wafer grinder based on wafer rotating grinding method. The calibrating experiments of the 3D grinding dynamometer are carried out. The FEA and modal analysis are made and compared with the results of mode testing. Furthermore, the static performance parameters of the dynamometer are obtained from the loading experiment. The experiment results indicate that the 3D grinding dynamometer can measure axial, radial and tangential grinding force of grinding wheel with high sensitivity, good linearity, good repeatability and high natural frequency, and fully satisfied requirement for measuring and monitoring of the grinding force in wafer grinding process.

Error Compensation in One-Point Inclined-Axis Nanogrinding Mode for Small Aspheric Mould

2010 ◽  
Vol 97-101 ◽  
pp. 4206-4212 ◽  
Author(s):  
Shao Hui Yin ◽  
Feng Jun Chen ◽  
Yu Wang ◽  
Yu Feng Fan ◽  
Yong Jian Zhu ◽  
...  
Keyword(s):  
Error Compensation ◽  
Single Point ◽  
Ground Surface ◽  
Compensation Method ◽  
Grinding Wheel ◽  
Form Error ◽  
Profile Data ◽  
Profile Error ◽  
Form Accuracy ◽  
Setting Error

A compensation method was proposed for correcting wheel setting error and residual form error in nanogrinding of axisymmetric surfaces. In this method, profile data from on-machine measurement were used to obtain the setting error of grinding wheel, as well as the normal residual form error. Compensation model of single-point inclined-axis grinding was built up for generating new compensation path. Grinding test of aspheric tungsten carbide mould was conducted to evaluate performances of the compensation method. A profile error of 182 nm (peak to valley) and average surface roughness of 1.71 nm were achieved. These results indicated that the form error compensation method may significantly improve form accuracy of ground surface.

The Adaptive Control of Grinding Force of CNC Cam Grinder Based on Neural Network

2012 ◽  
Vol 217-219 ◽  
pp. 2051-2055
Author(s):  
Ming Li Xie ◽  
Ling Lu
Keyword(s):  
Neural Network ◽  
Adaptive Control ◽  
Control Method ◽  
Metal Removal ◽  
Removal Rate ◽  
Grinding Force ◽  
Control Measures ◽  
Numerical Control ◽  
Grinding Wheel ◽  
Grinding Process

In the process of cam grinding, the fluctuation of grinding force can lead to the abnormal wear of the grinding wheel, the decrease of the grinding surface quality and even the damage of the grinding process system. The paper took the grinding process of numerical control cam grinding machine as research subject, the grinding force mathematical model was built, the indirect test and control measures were researched and an adaptive control method based on neural network was proposed and applied to the grinding force control of the cam grinding process. At last, the controller was designed and the grinding simulation was performed with MATLAB, which proved that the system could solve the fluctuation of grinding force during the process of cam grinding and the controller was equipped with good dynamic characteristic. The results indicate that the method can realize the purpose of optimal metal removal rate and enhance the grinding quality of cams.

Form Accuracy of Internal Grinding of Small and Deep Holes with Coolant Supplied from Inner Side of Grinding Wheel

2014 ◽  
Vol 1017 ◽  
pp. 50-54 ◽  
Author(s):  
Kosaku Matsubara ◽  
Jun Tsuchimura ◽  
Shota Kawazoe ◽  
Hiroyuki Sasahara
Keyword(s):  
Supply System ◽  
Grinding Wheel ◽  
Machined Surface ◽  
Steel Cylinder ◽  
Form Accuracy ◽  
Internal Grinding ◽  
Machining Center ◽  
Grinding Fluid ◽  
Grinding Conditions ◽  
Coolant System

Generally, grinding fluid is supplied from a nozzle to a grinding point. However, it is difficult to supply sufficient coolant to the deep grinding point of a hole. Therefore, we have proposed an alternative coolant system that supplies grinding fluid from the inner side of the grinding wheel utilizing the spindle through the supply system of the machining center. In this study, a new tool for small and deep holes was developed to supply grinding fluid in this way. The inside of a 0.45%C steel cylinder was then machined under various grinding conditions. Higher form accuracy and surface roughness were obtained under all conditions by supplying grinding coolant from the inner side of the grinding wheel. In addition, the system prevented tears on the machined surface and loading on the grinding wheel.

Research on the Grinding Force of the Basin-Like Grinding Wheel in Grinding Elliptical Grooves of Outer Race

2013 ◽  
Vol 823 ◽  
pp. 143-148
Author(s):  
Xiao Xue Li ◽  
Jun Ming Wang ◽  
Yu Qin Sun ◽  
Zhen Gang Gao
Keyword(s):  
High Speed ◽  
Grinding Force ◽  
The Other ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Feed Velocity ◽  
Outer Race ◽  
Abrasive Grains ◽  
Other Hand

In order to calculate the grinding force of the basin-like grinding wheel in grinding outer race elliptical grooves, the thesis simplifies the grinding process as follow: the evenly distributed abrasive grains move around grinding wheel axis along an imaginary ellipse at high speed, while the imaginary ellipse moves along the trace deflected from the grinding wheel axis simultaneously. The analysis of grinding force in CVJ outer race elliptical groove grinding with basin-like grinding wheel reveals that, the grinding force will be decreased, if wheel velocity increased and feed velocity decreased. On the other hand, with the decrease of inter-grain spacing, the grinding force of basin-like grinding wheel will be increased, but the grinding force of abrasive grit will be decreased.

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