The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Yongbo Wu - One of the best experts on this subject based on the ideXlab platform.
-
Evaluation of Grinding Conditions Using Dynamic Components of Grinding Force in Centerless Grinding.
Journal of The Japan Society for Precision Engineering, 2020Co-Authors: Yongbo Wu, Tsunemoto Kuriyagawa, Katsuo Syoji, Toru Tachibana, Masana KatoAbstract:This paper deals with an evaluation method of Grinding conditions in Centerless Grinding. It is difficult to optimize the Grinding conditions for minimizing the workpiece roundness error because there are lots of process parameters such as center height angle, blade angle and stock removal rate. We had proposed the waviness decrease rate as an evaluation function of Grinding conditions to select the optimum process parameters automatically. To build the closed-loop control system for the process parameters, however, it is necessary to find a practical way to measure the waviness decrease rate. In this paper, the relationship between the waviness decrease rate and the dynamic components of Grinding force was investigated analytically. It was found that the frequency characteristic of the waviness decrease rate shows a similar tendency to that of the dynamic components of Grinding force. Grinding force measurement system was built and measurement and evaluation of the Grinding force were carried out. As a result, it was confirmed that the Grinding conditions can be evaluated using the dynamic components of Grinding force.
-
simulation investigation of through feed Centerless Grinding process performed on a surface grinder
Journal of Materials Processing Technology, 2012Co-Authors: Weixing Xu, Yongbo WuAbstract:Abstract This paper proposes a simulation method for investigating the through-feed Centerless Grinding process performed on a surface grinder, where a compact Centerless Grinding unit, composed of a guide plate, an ultrasonic elliptic-vibration shoe, a blade, and their respective holders, is installed onto the worktable of a surface grinder, and the through-feed Centerless Grinding operation is performed as the workpiece located on the guide plate is fed into the space between the Grinding wheel and ultrasonic shoe. The geometrical arrangement of the Grinding apparatus including the contact lines on the Grinding wheel, ultrasonic shoe, and blade are analyzed firstly for building a 3-D simulation model. Then, the workpiece forming process and the effects of major process parameters such as the workpiece eccentric angle, the stock removal, the ultrasonic shoe tilt angle and the applied voltage amplitude on the machining accuracy (i.e. workpiece cylindricity and roundness) are clarified by simulation and experiments. The obtained results indicate that higher machining accuracy can be achieved under the conditions of larger workpiece stock removal, smaller ultrasonic shoe tilt angle and higher applied voltage amplitude, while the workpiece eccentric angle is at 6°.
-
a new through feed Centerless Grinding technique using a surface grinder
Journal of Materials Processing Technology, 2011Co-Authors: Weixing Xu, Yongbo WuAbstract:Abstract This paper proposes an alternative Centerless Grinding technique, i.e., through-feed Centerless Grinding using a surface grinder. In the new method, a compact Centerless Grinding unit, composed of a guide plate, an ultrasonic shoe, a blade, and their respective holders, is installed onto the worktable of a surface grinder, and the through-feed Centerless Grinding operation is performed as the workpiece located on the guide plate is fed into the space between the Grinding wheel and ultrasonic shoe. The ultrasonic shoe, produced by bonding a piezoelectric ceramic device onto a metal elastic body, is tilted at a small angle so as to provide sufficient force to control the workpiece rotational motion and to feed the workpiece along its axis by the ultrasonic elliptic-vibration. In this paper, the workpiece motion control tests were carried out firstly to make sure that the workpiece rotational speed and through-feed rate can be exactly controlled by the ultrasonic shoe which is essential for performing high-precision Grinding operations. Then, the effects of major process parameters such as the workpiece eccentric angle, the stock removal, the ultrasonic shoe tilt angle and the applied voltage amplitude on the machining accuracy (i.e. workpiece cylindricity and workpiece roundness) were clarified experimentally. The obtained results indicate that: (1) the workpiece rotational speed can be adjusted by changing the applied voltage amplitude, whereas its through-feed rate can be adjusted by changing both the applied voltage amplitude and the ultrasonic shoe tilt angle; (2) the optimum eccentric angle is 6°, and a larger stock removal, a smaller tilt angle, or a higher applied voltage is better for higher machining accuracy; (3) the workpiece cylindricity and roundness were improved from the initial value of 16.63 μm and 14.86 μm to the final ones of 1.49 μm and 0.74 μm under the optimal Grinding conditions.
-
Ceramic Balls Machining by Centerless Grinding Using a Surface Grinder
Advanced Materials Research, 2011Co-Authors: Yongbo Wu, Weixing Xu, Masakazu Fujimoto, T. TachibanaAbstract:This paper proposes a novel method for machining ceramic balls by Centerless Grinding technique performed on a surface grinder. In this method, a compact unit consisting mainly of an ultrasonic shoe, an ultrasonic regulator, a relay controller, a blade, a stopper and their respective holders is installed on the worktable of a surface grinder to conduct Centerless Grinding operations of ceramic balls. The ultrasonic shoe and regulator are produced by bonding a piezoelectric ceramic device (PZT) onto a metal elastic body, and when two phases of AC voltage are applied to the PZT an elliptic motion occurs on their end-faces which can be used to control the ball rotational motion in the radial and axial direction of the wheel, respectively. The function of the relay controller is to regulate the alternating current “on” and “off” time which is applied on the regulator for achieving the whole spherical surface Grinding process. A Grinding unit was actually constructed and it was experimentally confirmed that the ball rotational speed can be controlled well by the shoe or regulator. Grinding tests were subsequently carried out and the obtained results indicated that the constructed Grinding unit performed well on actual ball Centerless Grinding operations.
-
Performing in-feed type Centerless Grinding process on a surface grinder
2011Co-Authors: Weixing Xu, Yongbo Wu, T. SatoAbstract:In our previous study, a new Centerless Grinding method using surface grinder was proposed. In this method, Centerless Grinding operations are performed by installing a compact Centerless Grinding unit, consisting mainly of an ultrasonic elliptic‐vibration shoe, a blade and their respective holders, on the worktable of a surface grinder. During Grinding, the cylindrical workpiece is held on the ultrasonic shoe and the blade, and its rotational motion is controlled by the elliptic motion of the shoe end‐face. An actual unit had been produced and its performance in tangential‐feed type Centerless Grinding using a surface grinder had been confirmed in the previous workd. In this paper, the performance of the Grinding unit in in‐feed Centerless Grinding operation was confirmed, and the effects of the main process parameter, i.e., eccentric angle, on the workpiece roundness was investigated experimentally. The obtained results showed that: (1) the Centerless Grinding unit performed well in in‐feed type centerl...
D Barrenetxea - One of the best experts on this subject based on the ideXlab platform.
-
Increased productivity in Centerless Grinding using inertial active dampers
Cirp Annals-manufacturing Technology, 2018Co-Authors: D Barrenetxea, Iker Mancisidor, Xavier Beudaert, Jokin MunoaAbstract:Abstract Regenerative chatter during Centerless Grinding processes is one of the main factors limiting the productivity. This paper presents a novel chatter suppression technique for Centerless Grinding using an active damping system based on inertial actuators. Dynamic characterisation of the machine with and without active damping is used first to compute theoretical stability maps. The active nature of the system allows stabilising a wide working range of infeed operations. Finally, experimental results validate the predicted increase of stable Grinding area and verify that the technology is very effective for avoiding chatter, ensuring workpiece quality and increasing process productivity.
-
stability analysis and optimization algorithms for the set up of infeed Centerless Grinding
International Journal of Machine Tools & Manufacture, 2014Co-Authors: D Barrenetxea, I Gallego, Jorge Alvarez, J I Marquinez, Ignacio Muguerza Perello, Peter KrajnikAbstract:Abstract This paper introduces new algorithms for analysis and optimization of infeed Centerless Grinding, based on high-level integration of Grinding models into a web-based simulation. This holistic approach to simulation facilitates system-level simulation and solvers for several interlinked problems associated with the process mechanics. Emphasis is on structuring the model-based simulation as well as adapting and incorporating the underlying models into the algorithms. Geometric lobing-, chatter- and spinning-related process stability, as well as a time domain continuity equation, are integrated into the simulation to analyze the main quality-related limitations of the process. Once the process stability is assured for the process set-up, optimization strategies and a new infeed cycle definition function are proposed to achieve a minimal or target cycle time. An example of experimental optimization is provided to compare a high-quality process with a target cycle time to an optimized high-productivity process – demonstrating a 70% reduction in cycle time.
-
redesign of an active system of vibration control in a Centerless Grinding machine numerical simulation and practical implementation
Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2013Co-Authors: I Garitaonandia, Joseba Albizuri, M H Fernandes, J M Hernandezvazquez, I Olabarrieta, D BarrenetxeaAbstract:Abstract In this paper a novel methodology is presented to optimize an active chatter control system based on piezoelectric actuators in a Centerless Grinding machine. With the proposed modeling procedure, a compact and efficient control system is obtained, perfectly adapted to the specific characteristics of the machine. First, the previous theoretical and experimental works done in the Centerless Grinding machine under study are presented briefly, with emphasis on the development of a validated finite element (FE) model capable of predicting the behavior of the machine controlled actively. Afterwards, making use of this FE model, a theoretical procedure is developed to optimize the control system. Concretely, the piezoelectric actuators are redesigned to achieve a solution oriented to the specific characteristics of the machine and the control algorithm is adapted to the new design, leading to a highly integrated mechatronic solution. The new active control scheme is simulated using a reduced order state space model, verifying the effectiveness of the proposed solution. Finally, in line with the new design, a prototype is manufactured and integrated in the machine, and the experimental results obtained from different operating conditions are shown. The study of the theoretical and experimental results makes it possible to verify the improvements in the chatter stability of the process once the control system has been applied, as well as to confirm the theoretically predicted performance. This way, the work carried out in this paper shows the satisfactory use of a validated FE model to deal with the optimization process of an active vibration control system.
-
model based assistant tool for the setting up and optimization of Centerless Grinding process
Machining Science and Technology, 2012Co-Authors: D Barrenetxea, I Gallego, Jorge Alvarez, J I Marquinez, J Madariaga, Raul Fernandez, Iker GaritaonaindiaAbstract:Recent advances in process modeling allow for more accurate prediction of complex phenomena. A combination of different modeling approaches makes it possible to develop new products to set up, control and optimize machining operations. In the near future, a continuous improvement strategy should be adopted, as improvements to advanced models open up new opportunities for industrial applications. In particular, the efforts made by different research groups on Grinding have given rise to significant developments in this area, some of which have recently been made into applied software. As an example of the necessity for process modeling and the viability of industrialized tools based on it, this article presents the work carried out on the development of an assistant tool for the setting up and optimization of the Centerless Grinding process, focusing on avoiding the main limitations of this process and optimizing productivity.
-
advances in Centerless Grinding technology
Cirp Annals-manufacturing Technology, 2012Co-Authors: Fukuo Hashimoto, I Gallego, Joao Fernando Gomes De Oliveira, D Barrenetxea, Mitsuaki Takahashi, Kenji Sakakibara, Hansolof Stalfelt, Gerd Staadt, Koji OgawaAbstract:Abstract This paper reviews the history of Centerless Grinding and its contribution to industry. It summarizes the evolution of Centerless Grinding theory including advanced modeling and simulation. Then, it discusses the design of main elements of a Centerless Grinding machine such as spindles, bed, guideways and positioning system, and provides design guidelines for future machines. The paper presents the state-of-the-art Centerless Grinding technologies: advanced machines, advanced process monitoring and the latest developments in Grinding wheels. Finally, in conclusion, future trends and research work in Centerless Grinding technology are discussed.
I Gallego - One of the best experts on this subject based on the ideXlab platform.
-
stability analysis and optimization algorithms for the set up of infeed Centerless Grinding
International Journal of Machine Tools & Manufacture, 2014Co-Authors: D Barrenetxea, I Gallego, Jorge Alvarez, J I Marquinez, Ignacio Muguerza Perello, Peter KrajnikAbstract:Abstract This paper introduces new algorithms for analysis and optimization of infeed Centerless Grinding, based on high-level integration of Grinding models into a web-based simulation. This holistic approach to simulation facilitates system-level simulation and solvers for several interlinked problems associated with the process mechanics. Emphasis is on structuring the model-based simulation as well as adapting and incorporating the underlying models into the algorithms. Geometric lobing-, chatter- and spinning-related process stability, as well as a time domain continuity equation, are integrated into the simulation to analyze the main quality-related limitations of the process. Once the process stability is assured for the process set-up, optimization strategies and a new infeed cycle definition function are proposed to achieve a minimal or target cycle time. An example of experimental optimization is provided to compare a high-quality process with a target cycle time to an optimized high-productivity process – demonstrating a 70% reduction in cycle time.
-
model based assistant tool for the setting up and optimization of Centerless Grinding process
Machining Science and Technology, 2012Co-Authors: D Barrenetxea, I Gallego, Jorge Alvarez, J I Marquinez, J Madariaga, Raul Fernandez, Iker GaritaonaindiaAbstract:Recent advances in process modeling allow for more accurate prediction of complex phenomena. A combination of different modeling approaches makes it possible to develop new products to set up, control and optimize machining operations. In the near future, a continuous improvement strategy should be adopted, as improvements to advanced models open up new opportunities for industrial applications. In particular, the efforts made by different research groups on Grinding have given rise to significant developments in this area, some of which have recently been made into applied software. As an example of the necessity for process modeling and the viability of industrialized tools based on it, this article presents the work carried out on the development of an assistant tool for the setting up and optimization of the Centerless Grinding process, focusing on avoiding the main limitations of this process and optimizing productivity.
-
advances in Centerless Grinding technology
Cirp Annals-manufacturing Technology, 2012Co-Authors: Fukuo Hashimoto, I Gallego, Joao Fernando Gomes De Oliveira, D Barrenetxea, Mitsuaki Takahashi, Kenji Sakakibara, Hansolof Stalfelt, Gerd Staadt, Koji OgawaAbstract:Abstract This paper reviews the history of Centerless Grinding and its contribution to industry. It summarizes the evolution of Centerless Grinding theory including advanced modeling and simulation. Then, it discusses the design of main elements of a Centerless Grinding machine such as spindles, bed, guideways and positioning system, and provides design guidelines for future machines. The paper presents the state-of-the-art Centerless Grinding technologies: advanced machines, advanced process monitoring and the latest developments in Grinding wheels. Finally, in conclusion, future trends and research work in Centerless Grinding technology are discussed.
-
effectiveness of continuous workpiece speed variation cwsv for chatter avoidance in throughfeed Centerless Grinding
International Journal of Machine Tools & Manufacture, 2011Co-Authors: Jorge Alvarez, D Barrenetxea, J I Marquinez, I Bediaga, I GallegoAbstract:Abstract The continuous rotation speed variation is demonstrated to be an efficient method to avoid regenerative chatter in different machining processes. This paper presents a time-domain dynamic model for throughfeed Centerless Grinding process that can predict chatter by means of part roundness error evolution. Continuous workpiece speed variation (CWSV) has been implemented in this model to analyze the influence of this disturbing method on the dynamic instability. Experimental results have validated the model and verified the effectiveness of CWSV for chatter avoidance and surface finish and dimensional tolerances improvement. It has been demonstrated that the selection of the optimal variation parameters is an important factor not only for chatter avoidance, but also for the stability of surface finish and dimensional tolerances since workpiece speed variation has a direct influence on throughfeed rate and Grinding forces.
-
Stability analysis and time domain simulation of multiple diameter parts during infeed Centerless Grinding
Cirp Annals-manufacturing Technology, 2011Co-Authors: D Barrenetxea, Jorge Alvarez, J Madariaga, I GallegoAbstract:Abstract Multiple diameter part applications cope a relevant percentage of infeed Centerless Grinding operations. Nevertheless, general stability analysis and process optimisation has been mainly investigated for mono-diameter parts. This paper presents a time domain simulation software developed for multiple diameter parts that allows the simulation of average and particular evolution of process forces, power, machine deflections, thermal behaviour, real part diameter and roughness. First, a work rotation stability analysis is carried out. Then, with the use of both the stability analysis and the infeed cycle simulation, optimized process parameters and cycles are defined in order to increase process productivity.
Weixing Xu - One of the best experts on this subject based on the ideXlab platform.
-
simulation investigation of through feed Centerless Grinding process performed on a surface grinder
Journal of Materials Processing Technology, 2012Co-Authors: Weixing Xu, Yongbo WuAbstract:Abstract This paper proposes a simulation method for investigating the through-feed Centerless Grinding process performed on a surface grinder, where a compact Centerless Grinding unit, composed of a guide plate, an ultrasonic elliptic-vibration shoe, a blade, and their respective holders, is installed onto the worktable of a surface grinder, and the through-feed Centerless Grinding operation is performed as the workpiece located on the guide plate is fed into the space between the Grinding wheel and ultrasonic shoe. The geometrical arrangement of the Grinding apparatus including the contact lines on the Grinding wheel, ultrasonic shoe, and blade are analyzed firstly for building a 3-D simulation model. Then, the workpiece forming process and the effects of major process parameters such as the workpiece eccentric angle, the stock removal, the ultrasonic shoe tilt angle and the applied voltage amplitude on the machining accuracy (i.e. workpiece cylindricity and roundness) are clarified by simulation and experiments. The obtained results indicate that higher machining accuracy can be achieved under the conditions of larger workpiece stock removal, smaller ultrasonic shoe tilt angle and higher applied voltage amplitude, while the workpiece eccentric angle is at 6°.
-
a new through feed Centerless Grinding technique using a surface grinder
Journal of Materials Processing Technology, 2011Co-Authors: Weixing Xu, Yongbo WuAbstract:Abstract This paper proposes an alternative Centerless Grinding technique, i.e., through-feed Centerless Grinding using a surface grinder. In the new method, a compact Centerless Grinding unit, composed of a guide plate, an ultrasonic shoe, a blade, and their respective holders, is installed onto the worktable of a surface grinder, and the through-feed Centerless Grinding operation is performed as the workpiece located on the guide plate is fed into the space between the Grinding wheel and ultrasonic shoe. The ultrasonic shoe, produced by bonding a piezoelectric ceramic device onto a metal elastic body, is tilted at a small angle so as to provide sufficient force to control the workpiece rotational motion and to feed the workpiece along its axis by the ultrasonic elliptic-vibration. In this paper, the workpiece motion control tests were carried out firstly to make sure that the workpiece rotational speed and through-feed rate can be exactly controlled by the ultrasonic shoe which is essential for performing high-precision Grinding operations. Then, the effects of major process parameters such as the workpiece eccentric angle, the stock removal, the ultrasonic shoe tilt angle and the applied voltage amplitude on the machining accuracy (i.e. workpiece cylindricity and workpiece roundness) were clarified experimentally. The obtained results indicate that: (1) the workpiece rotational speed can be adjusted by changing the applied voltage amplitude, whereas its through-feed rate can be adjusted by changing both the applied voltage amplitude and the ultrasonic shoe tilt angle; (2) the optimum eccentric angle is 6°, and a larger stock removal, a smaller tilt angle, or a higher applied voltage is better for higher machining accuracy; (3) the workpiece cylindricity and roundness were improved from the initial value of 16.63 μm and 14.86 μm to the final ones of 1.49 μm and 0.74 μm under the optimal Grinding conditions.
-
Ceramic Balls Machining by Centerless Grinding Using a Surface Grinder
Advanced Materials Research, 2011Co-Authors: Yongbo Wu, Weixing Xu, Masakazu Fujimoto, T. TachibanaAbstract:This paper proposes a novel method for machining ceramic balls by Centerless Grinding technique performed on a surface grinder. In this method, a compact unit consisting mainly of an ultrasonic shoe, an ultrasonic regulator, a relay controller, a blade, a stopper and their respective holders is installed on the worktable of a surface grinder to conduct Centerless Grinding operations of ceramic balls. The ultrasonic shoe and regulator are produced by bonding a piezoelectric ceramic device (PZT) onto a metal elastic body, and when two phases of AC voltage are applied to the PZT an elliptic motion occurs on their end-faces which can be used to control the ball rotational motion in the radial and axial direction of the wheel, respectively. The function of the relay controller is to regulate the alternating current “on” and “off” time which is applied on the regulator for achieving the whole spherical surface Grinding process. A Grinding unit was actually constructed and it was experimentally confirmed that the ball rotational speed can be controlled well by the shoe or regulator. Grinding tests were subsequently carried out and the obtained results indicated that the constructed Grinding unit performed well on actual ball Centerless Grinding operations.
-
Performing in-feed type Centerless Grinding process on a surface grinder
2011Co-Authors: Weixing Xu, Yongbo Wu, T. SatoAbstract:In our previous study, a new Centerless Grinding method using surface grinder was proposed. In this method, Centerless Grinding operations are performed by installing a compact Centerless Grinding unit, consisting mainly of an ultrasonic elliptic‐vibration shoe, a blade and their respective holders, on the worktable of a surface grinder. During Grinding, the cylindrical workpiece is held on the ultrasonic shoe and the blade, and its rotational motion is controlled by the elliptic motion of the shoe end‐face. An actual unit had been produced and its performance in tangential‐feed type Centerless Grinding using a surface grinder had been confirmed in the previous workd. In this paper, the performance of the Grinding unit in in‐feed Centerless Grinding operation was confirmed, and the effects of the main process parameter, i.e., eccentric angle, on the workpiece roundness was investigated experimentally. The obtained results showed that: (1) the Centerless Grinding unit performed well in in‐feed type centerl...
-
a new in feed Centerless Grinding technique using a surface grinder
Journal of Materials Processing Technology, 2011Co-Authors: Weixing Xu, Yongbo WuAbstract:Abstract This paper deals with the development of an alternative Centerless Grinding technique, i.e., in-feed Centerless Grinding based on a surface grinder. In this new method, a compact Centerless Grinding unit, composed of an ultrasonic elliptic-vibration shoe, a blade and their respective holders, is installed onto the worktable of a surface grinder, and the in-feed Centerless Grinding operation is performed as a rotating Grinding wheel is fed in downward to the cylindrical workpiece held on the shoe and the blade. During Grinding, the rotational speed of the workpiece is controlled by the ultrasonic elliptic-vibration of the shoe that is produced by bonding a piezoelectric ceramic device (PZT) on a metal elastic body (stainless steel, SUS304). A simulation method is proposed for clarifying the workpiece rounding process and predicting the workpiece roundness in this new Centerless Grinding, and the effects of process parameters such as the eccentric angle, the wheel feed rate, the stock removal and the workpiece rotational speed on the workpiece roundness were investigated by simulation followed by experimental confirmation. The obtained results indicate that: (1) the optimum eccentric angle is around 6°; (2) higher machining accuracy can be obtained under a lower Grinding wheel feed rate, larger stock removal and faster workpiece rotational speed; (3) the workpiece roundness was improved from an initial value of 19.90 μm to a final one of 0.90 μm after Grinding under the optimal Grinding conditions.
M Kato - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Ultrasonic Elliptic Vibration on Friction between Shoe and Workpiece in Ultrasonic Elliptic-Vibration Shoe Centerless Grinding
Key Engineering Materials, 2005Co-Authors: Yongbo Wu, Toru Tachibana, M KatoAbstract:This paper describes an experimental investigation of the effect of ultrasonic elliptic vibration of the shoe on the friction between the shoe and the workpiece in ultrasonic elliptic-vibration shoe Centerless Grinding, a new Centerless Grinding technique proposed previously by the present authors. In the new technique, an ultrasonic elliptic-vibration shoe is employed to control the workpiece rotational speed as a regulating wheel does in conventional Centerless Grinding. The Grinding accuracy is affected significantly by the workpiece rotation stability, which is dependent on the frictional force between the workpiece and the ultrasonic elliptic-vibration shoe. The issue relating to the friction between the workpiece and the shoe is therefore very important in the complete establishment of the new Centerless Grinding technique. In the present work, in order to clarify the effect of ultrasonic elliptic vibration of the shoe on the frictional coefficient and to determine the appropriate ultrasonic elliptic vibration conditions, a measurement apparatus was built up in-house and used to measure the frictional coefficient under the presence and absence of the ultrasonic elliptic vibration. The measurement results indicated that the frictional coefficient decreases with increase in the size of the ultrasonic elliptic motion, and a shape of the elliptic motion, in which the frictional coefficient reaches maximum, exists.
-
a new Centerless Grinding technique using a surface grinder
Journal of Materials Processing Technology, 2005Co-Authors: Yongbo Wu, T Kondo, M KatoAbstract:Abstract This paper proposes a new Centerless Grinding technique using a surface grinder. By this technique Centerless Grinding operations can be performed at low cost by installing a compact Centerless Grinding unit on the worktable of a multipurpose surface grinder and without the employment of a costly Centerless grinder. The unit consists mainly of an ultrasonic elliptic-vibration shoe, a blade, and their respective holders. The shoe is produced by bonding a piezoelectric ceramic device (PZT) on a metal elastic body (stainless steel, SUS304), and an elliptic motion occurs on its end-face when two phases of AC voltage are applied to the PZT. The function of the shoe is to hold the cylindrical workpiece in conjunction with the blade, and to control the workpiece rotational speed with the elliptic motion on its end-face during Grinding. The detailed structure of the unit was designed by Finite Element Method (FEM) analysis, and an actually constructed unit was installed on the worktable of a CNC surface grinder to perform tangential Centerless Grinding operations after its fundamental performance such as elliptic motion generation and capacity to control workpiece rotational speed had been investigated. As a result, it was clarified that the workpiece rotational speed changes linearly with variation in the applied voltage. This indicates that the workpiece rotational motion can be precisely controlled by the elliptic motion of the shoe. In addition, the workpiece roundness was clearly improved from an initial value of 23 μm to a final value of 2.6 μm after Grinding, indicating that the constructed unit performed well in actual Grinding operations.
-
development of an ultrasonic elliptic vibration shoe Centerless Grinding technique
Journal of Materials Processing Technology, 2004Co-Authors: Yongbo Wu, M Kato, Tsunemoto Kuriyagawa, Katsuo Syoji, Toru TachibanaAbstract:Abstract This paper describes the development of a new Centerless Grinding technique called the ultrasonic elliptic-vibration shoe Centerless Grinding. This new method employs an ultrasonic elliptic-vibration shoe to support the workpiece and control the workpiece rotational motion instead of using a regulating wheel such as that employed in conventional Centerless Grinding. First, an experimental apparatus is established by designing and producing an ultrasonic elliptic-vibration shoe and a fine feed mechanism, and then attaching them on a conventional Centerless grinder which is commercially available. Next, in order to clarify the performance of the constructed equipment, the elliptic motion of the shoe-end-face is investigated using laser vibrometers, in addition to workpiece rotational motion control tests under a Grinding-like configuration. Finally, in order to confirm the validity of the new method and to determine the optimum geometrical arrangement of the shoe, Grinding experiments involving pin-shaped workpieces with an initial roundness of 25 μm are conducted on the established equipment for various values of the shoe tilt angle γ. The results obtained indicated that the roundness improved for any values of γ, and that γ=7° gave the minimum roundness error, confirming the validity of this technique.