Xi Jing Zhu

Study on Friction Chatter Mechanism of Power Ultrasonic Vibration Honing Based on Stribeck Effect

Chatter easily occurs in machining, which is influenced by many factors. The power ultrasonic vibration honing equipment is taken as the research object, the dynamic friction, is studied and the dynamics model is established based on the Stribeck model and the phase trajectories and time responses are analyzed by piece-wise linear method in this paper. The results show that the system is stable and convergence rate is affected by the equivalent elastic coefficient k, the damping coefficient c and c1, the positive pressure value of N if the honing speedor. The system is critical stable and the values of k,c,Nsatisfy if or. So it should be considered that appropriately reduce the values of k, c, N when the system is designed.

Dynamics Modeling of Cavitation Bubble in the Grinding Area of Power Ultrasonic Honing

t can particularly generate abundant cavitation bubbles in the processing of the power ultrasonic honing. The dynamics of cavitation bubbles in the grinding area are very vital to study the machining mechanism and the cutting chatter of power ultrasonic honing. Based on the Rayleigh-Plesset equation, a new dynamics model of cavitation bubble is established, considering the velocity of ultrasonic honing and honing pressure. With the superposition principle of velocity potential, the dynamics of double cavitation bubble is also established. Moreover, the dynamic characteristics of cavitation bubble also can be simulated numerically. The results show that cavitation bubble in the grinding zone begins to grow extensively and then undergoes collapse, and even subsequent rebound and then. The variation trend of radius change of double cavitation bubble in the grinding area is more than that of single cavitation bubble by an order of magnitude.

A New Technology of Improving Surface Quality of Engine Cylinder

This paper introduces the new technology of ultrasonic vibration honing, and analyzes the cutting principle of ultrasonic honing in terms of cutting motion, grain performance and cutting quantity. Then, the applied effect used in the cast-iron cylinder of DY90 is introduced. The principle and the structure of this device are discussed. This new technology can further be used in micro-car’s cylinder, can provides a high-productivity, high-quality for cast-iron cylinder.

Research on Power Ultrasonic Vibration Honing of Sintered Nd-Fe-B

The technology of power ultrasonic vibration honing was used for the brittle hard sintered Nd-Fe-B materials in this paper. The feasibility and correctness of machining process was analyzed through experiments. Compared normal process result with orthogonal experiments, it was better to use power ultrasonic vibration honing to obtain parts with less surface roughness and higher material removal rate, and also the optimal processing parameters can be conduct. Therefore, the power ultrasonic vibration honing can be used to improve workpiece surface quality, as well as processing efficiency, precision, which is an effective method for precise machining of sintered Nd-Fe-B materials.

Radial Power Ultrasonic Vibration Honing Friction Analysis

Grinding chatter is a hazardous phenomenon that frequently occurred during grinding process. The topic takes radial ultrasonic vibration honing as an example to explore the dynamic changes of grinding force in ultrasonic honing process. By analyzing obtains the following conclusions: (1) The friction coefficient between work-piece and whetstone is a nonlinear time variable; (2) Adding radial ultrasonic is mainly to change the positive pressure between whetstone and work-piece, thereby affects the mutual friction between work-piece and oilstone in honing; (3) Whether ordinary honing or ultrasonic honing, friction dynamic changes along with time, performance of whetstone relative to work-piece is discontinuous sliding —jerking motion.

Study on Ultrasonic Cavitation Mechanism of Honing

Ultrasonic cavitation is an extremely complex physical phenomenon. It displays a series of nonlinear dynamics as the bubbles oscillating, growth, shrinkage and even collapse. For ultrasonic honing, it causes the device to generate chatter and noise because of the cavitation effect, and even generates denudation on the workpiece surface. In this paper, it describes the cavitation mechanism in ultrasonic honing, and analysises the acoustic pressure of the formation of cavitation from the numerical, furthermore it experimentally demonstrated. It also analyzes the nonlinear oscillation of cavitation bubbles for the impact on the ultrasonic honing chatter. Through studying on ultrasonic cavitation mechanism of honing, it provided a theoretical basis to solution the problem of the ultrasonic honing chatter and improves the level of precision and ultra precision machining.

The Study of Power Ultrasonic Vibration Cutting Heat

Cutting heat and the resulting temperature change material properties, thus it produces tremendous influence to cutting force, tool condition and surface roughness. The cutting heat generated by the power ultrasonic vibration cutting process were is calculated in this paper, the power ultrasonic vibration cutting is studied by using the finite element software, the conclusions are that during power ultrasonic vibration cutting, the cutting heat generated depends on the net cutting time of a vibration cycle, the rapid cooling is the main reason for lower cutting temperature in the separation stage of the workpiece and tool, and the maximum temperature of the tool is greater than conventional turning, but the average temperature of the tool is low than traditional turning.

Test Research on Grinding Performance of the New Grinding Fluid in Power Ultrasonic Honing

Grinding fluid has an important effect in processing work piece, so in view of the new grinding fluid, a large number of tests have been taken in the application of the power ultrasonic vibration honing. The massive experimental study, separated from the work piece’s surface roughness, the work piece’s surface rubbed deterioration layer and the influence to the processing characteristic with different density of the new grinding fluid and so on, discussed the adaptability of the new grinding fluid in power ultrasonic vibration honing processing. The research has been indicated that although the new grinding fluid does not surpass the traditional working fluid, such as emulsion and liquor, in cooling performance, it has a better lubricating property and has the obvious superiority in the working accuracy and the oilstone’s length of life. Therefore the new self-developed grinding fluid is suitable for the power ultrasonic honing processing.

The Single-Abrasive Coupled Flutter Model in Power Ultrasonic Honing

Flutter, a dynamic and severe self-excited vibration, easily produced in power ultrasonic honing, is one of the important factors, which affects the processing quality of the workpiece, the efficiency of the machine tool. Based on the study of power ultrasonic honing mechanism, choosing single abrasive and workpiece as research objects, respectively establishe the physical and mathematical coupled flutter model of power ultrasonic honing nonlinear system, with two degrees of freedom, determine the differential expression of the model, and simulate the boundry of flutter condition. It is proved flutter is produced in ultrasonic vibration honing, then the way is proposed to restrain. The study provide a theoretical basis for deeply seeking the strategy to repress and eliminate the flutter.

Modeling of Force on Axial Power Ultrasonic Honing

Ultrasonic vibration machining is a kind of effective method for precision processing of brittle-hard materials, especially it can obtain good surface quality in engine cylinder liner precision processing with the power ultrasonic honing. Based on the material removal mechanism of ultrasonic honing, a new ultrasonic honing force model was established, which included material chip deformation and friction situation between grains and workpiece. Therefore the effect to honing force can be known clearly with processing parameters and material physical change, which provided theory foundation to further study in ultrasonic mechanism and real time surface quality protection in honing process.