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 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

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.

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.

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.

Measurement of the Interfacial Stresses in Rolling Using the Elastic Deformation of the Roll

1987 ◽  
Vol 109 (4) ◽  
pp. 362-369 ◽  
Author(s):  
D. J. Meierhofer ◽  
K. A. Stelson
Keyword(s):  
Elastic Deformation ◽  
Normal Pressure ◽  
New Method ◽  
Frictional Stress ◽  
Stress Distributions ◽  
Strain Gages ◽  
Experimental Rolling ◽  
Mechanical Isolation ◽  
Roll Gap ◽  
Future Work

A new method to measure the frictional stresses and normal pressure in the roll gap during cold rolling, and experimental verification of this new method, are presented. The method overcomes many of the shortcomings of pin-type sensors. The elastic deformation of the roll itself is measured with strain gages, and is used to calculate the stresses between the sheet and the roll. Since no modification of the roll is necessary, the deformation process is undisturbed by the measurement. Mechanical isolation of the sensor is unnecessary. The mathematical procedure used to calculate the normal pressure and frictional stresses from the measured strains explicitly acknowledges that these strains are the result of the entire distribution of pressures and shears in the roll gap. An experimental rolling mill was constructed to verify the proposed method. Lead was rolled, and the resulting pressure and frictional stress distributions in the roll gap were measured. Several features of these distributions are in agreement with measurements made by various investigators using other techniques, thereby confirming the usefulness of the new method. Future work is proposed to increase the accuracy with which the roll gap stresses may be measured.

The influence of the form error and rough datum surface position on the accuracy of manufacturing of the “box-type product”

2021 ◽  
Vol 2021 (12) ◽  
pp. 37-43
Author(s):  
Aleksandr Yamnikov ◽  
Evgeniy Danilenko
Keyword(s):  
New Method ◽  
Form Error

The influence of the form error and rough datum surface position on the accuracy of manufacturing parts of reduced rigidity is considered. A sketch diagram of the allocation of technological zones is presented. A new method for allocating technological zones is proposed.

New Deployable Structures Based on an Elastic Origami Model

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Kazuya Saito ◽  
Akira Tsukahara ◽  
Yoji Okabe
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Simple Model ◽  
Elastic Deformation ◽  
Initial Strain ◽  
New Method ◽  
The Finite Element Method ◽  
Deployable Structures ◽  
Elastic Deformations ◽  
Plate Models

Traditionally, origami-based structures are designed on the premise of “rigid folding,” However, every act of folding and unfolding is accompanied by elastic deformations in real structures. This study focuses on these elastic deformations in order to expand origami into a new method of designing morphing structures. The authors start by proposing a simple model for evaluating elastic deformation in nonrigid origami structures. Next, these methods are applied to deployable plate models. Initial strain is introduced into the elastic parts as actuators for deployment. Finally, by using the finite element method (FEM), it is confirmed that the proposed system can accomplish the complete deployment in 3 × 3 Miura-or model.

A New Method for the Analysis of Deformation and Load in a Ball Bearing With Variable Contact Angle

1999 ◽  
Vol 123 (2) ◽  
pp. 304-312 ◽  
Author(s):  
Neng Tung Liao ◽  
Jen Fin Lin
Keyword(s):  
Contact Angle ◽  
Elastic Deformation ◽  
Newton Method ◽  
Contact Surface ◽  
Ball Bearing ◽  
Three Dimensional ◽  
Position Angle ◽  
New Method ◽  
Mechanism Analysis ◽  
Acting Force

The contact angle of a ball in a ball bearing is conventionally assumed to be a constant value in the mechanism analysis; in reality, this is not true. This assumption is made for the purpose of simplifying calculations, but the real elastic deformation produced at the position of each ball due to the acting force varying with the contact angle is unable to be considered. This study tries to establish a simple, three-dimensional expression for the elastic deformation at different position angles in terms of the geometry of the contact surface at the inner and outer races. Simply using the Newton method when the bearing deformations in the radial and axial directions are available can solve the contact angle as a function of position angle. Several characteristics arising from the variable contact angle will be discussed.

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