Papers by Keyword: Vibration Cutting

Abstract: The processing of materials with a hardness greater than 55 HRC has always required the use of unconventional or grinding methods in order to obtain the quality and precision required by the technical conditions. For these reasons, the researches of the last decades have developed an unconventional method of processing, with great precision and precision, by assisting the classic processing techniques, with forced, unamortized, low amplitude ultrasonic vibrations. The present paper presents the results of some researches regarding the processing of extradural materials, by the assisted realization of the non-cushioned, low amplitude ultrasonic vibrations. It is demonstrated that this method of processing can obtain very fine surfaces, sometimes being able to replace the grinding, with much lower costs, in terms of energy consumption and tool wear.

Abstract: The purpose of this paper is to investigate the variation of temperature field of ultrasonic vibration assisted milling compared with that of conventional milling by FEM method. An equivalent two-dimensional finite element model was built to simplify the complexity of calculation. As results, the temperature field distribution, the variation of tool tip temperature and the change of heat generation rate in ultrasonic vibration assisted milling were analyzed compared with that in conventional milling process. According to analytical results, the application of ultrasonic vibration in milling process can significantly improve the distribution of cutting temperature, and reduce the impacts of thermal deformation and various thermal effects to cutting process.

Abstract: In this paper, the author constructs a dimensionless nonlinear dynamic model of Vibration cutting system described by nonlinear differential equations. The model is established on the relationship between cutting force and cutting speed and the relationship of cutting depth to the cutting resistance and the time. It is the nonlinear dynamic friction model of vibration cutting considering tool-chip friction. Based on the model and the method of chaotic identification, Lyapunov Exponent, the further research on the vibration cutting produce behavior and its classification are conducted.

Abstract: Elliptical vibration cutting is a new processing technology of work piece surface texture generation, the technique based on conventional cutting machine main movement and feed motion of the tool, by changing the structure so that the tip motion to generate ellipse trajectory. This paper designed incentive range vibration frequency as 20~40 KHz, can generate elliptical vibration trajectory in the small space of X/Z axis 16um. Tests prove that, the ultrasonic elliptic vibration cutting mechanism improves the specimen surface texture, smooth discharging of chipping, greatly improving the surface finishes of the work piece.

Abstract: During the traditional cutting processing, cutting tool and the workpiece contact each other continuously along with the chip removal, this paper puts forward a kind of vibration cutting structure based on the parallel mechanism known as 2R-2P, in which certain elliptical trajectory could be taken, according to the principle of applying separate characteristic between vibrating cutting tool and workpiece to lower cutting force, cutting temperature, so as to improve the machining accuracy. Firstly, illustration in the mechanism of formating the surface morphology in elliptical vibration cutting and the micro trajectory of tip is carried out, secondly, completing the structure design and kinematics analysis, the tip vibration curve has been attained. Finally, through the statics and dynamics analysis, distribution rule of stress and strain is concluded when the structure is subjected to external force changing periodically, as the vibration mode and the harmonious response, verifying the feasibility of the structure and the ability of tip vibrating in ellipse trajectory.

Abstract: Due to intermitted cut characteristics, ultrasonic elliptical vibration cutting offers many benefits e.g. reducing tool force, improving surface finish and extending tool life. This paper presents the model-based development of an ultrasonic elliptical vibration cutting device with 1st resonant mode of longitudinal vibration and 3 rd resonant mode of bending vibration. The development of the device was assisted with the finite element program ANSYS. Based on theoretical and experimental studies, the requirements of the device are estimated. The maximum displacement amplitude of the ultrasonic elliptical vibration cutting device is 13.1μm and 8.3μm for bending vibration and longitudinal vibration respectively at an exciting voltage of 400V_p-p.

Abstract: Proposed a concept, “cutting degree” as one of the parameters indicating the surface characteristics of the machined layer integrity. According to material nonlinearity, geometric nonlinearity, thermal coupling theory, established models of the vibratory cutting simulation, constitutive J-C model, shear model, boundary conditions, made finite element simulation of low-frequency vibration cutting by using software. Accessing to a visualization process, which is the change of material stress state in local area of the workpiece in cutting process. Analyzed the change of material stress states in local area of the workpiece, between low-frequency vibration cutting and non-vibration cutting machining process, other cutting parameters being equal. It is found that the values of cutting degree were apparently different in vibration cutting from those in non-vibration cutting. Contrasting experiments were done and SEM was observed of the machined surfaces. Findings of the experiment supported the simulation and to some extent validated the feasibility of the vision of 'cutting degree' as a term for expression of vibration cutting feature.

Abstract: The vibration cutting is better than the ordinary cutting because the slight division effect, which is created in the vibratory cutting process, reduces the cutting resistance. Kinematic analyzing of the vibration cutting process, dynamic model of the vibration cutting mechanism and simulation analysis are developed. A contrastive analysis on the movement relationship between the cutting tool and the paper stack is given during the ordinary and vibration cutting process respectively. The relative position of the cutting tool and paper stack at different cutting velocity is analyzed and the best cutting speed is given. The conclusions are as follows. The precondition of realizing the vibration cutting effect is that the cutting speed is smaller than the maximum vibration velocity of cutting knife. The vibration force is obtained and enhancing vibration force can reduce the cutting resistance.

Abstract: The specification of the vibration cutting loading is a decision factor for the generation of stress wave and the stress wave propagation has a significant impact on its micro-mechanism. Making the stress waves’ generation in the cutting area of vibration cutting for entry point, the analysis of internal inflection wave, inflection fracture and dynamic stress intensity factor has been carried out, the simulation of vibration cutting has also been done by finite element method, the essential of energy concentrated role, shear angle increment and cutting quality improvement has been explained.

Abstract: Research on the mechanism of vibration cutting was carried out by analyzing the process of vibration cutting and comparing the model of vibration cutting and conventional cutting. Proper speed coefficient k can help to reduce the average cutting force while increase the cutting efficiency according to the velocity and acceleration equation of vibration tool. Dynamic model of conventional cutting and vibration cutting were built respectively. Compared with conventional cutting, it’s easier for vibration cutting to realize productivity gain, high machining accuracy and good surface finish.