| Rotary ultrasonic machining is a hybrid machining process which combines the material removal mechanisms of conventional ultrasonic machining (CUSM) and diamond grinding. It is not limited by the electrical or chemical characteristics of the workpiece materials. Thus it has been proved to be a promising and cost-effective machining method for hard and brittle materials, such as engineering ceramic, glass, stone, which has been widely used in many fields such as electronics, metallurgy, chemistry industry, machine, energy power, aviation and space flight.However, referenced from a variety of literature and the actual investigation, marketability and perfect rotary ultrasonic machining equipment had been in oversea market for many years ago. But at present, we cannot find one with our Chinese Independent property right, it in turn, compared with developed country, we have a poor level at the technology of rotary ultrasonic machining.This article attempts to carry out series of work on the design and development of rotary ultrasonic equipment, beared with the characteristic of reasonable configuration, operating convenience, perfect performance, high efficiency and low cost. It can be suitable in the hole and face processing with a level of high power and spindle rotary speed. Based on this foundation, serials experiment will be carried out to reveal the materials removal principle and the attrition of diamond tool during rotary ultrasonic processing on stone materials.The main work of this thesis can be summarized as following:1. To design an ultrasonic power supply with 1000 watts power. In order to be suitable with different working status, the power supply should have the function of automatic frequency tracking, power adjusting and also impedance matching.2. Based on the theory of one-dimensional vibration and the method of mechanical-electrical equivalent, a sandwich type of piezoelectricity ceramic transducer was developed. From the point of basic principle of matching and the equivalent circuit near resonance frequency of piezoelectricity transducer, resonance characteristic of serial and parallel matching have been analyzed. The main parameters of designed transducer wear tested by an impedance analyzer, results revealed they were well accorded with the design target, it just has a 0.8% error between the testing resonance frequency with the theoretical one.3. Stepped horn was theoretically calculated. In virtue of Finite Element Analysis, desired natural frequency and vibration model of the horn was analyzed, giving the optimal transition circular radius and the displacement nodal point. So the acoustical couplings energy will remarkably decreased between the whole ultrasonic oscillator and the engine bed through the flange setted up form the accurate nodal point. The main parameters of the whole ultrasonic oscillator wear tested, results revealed they were well accorded with the design target, it just has a 0.2% error between the testing resonance frequency with the theoretical one.4. At present, ultrasonic machining experiments study were mainly limited to the little hole machining of ceramics. As a comparison, a typical kind of stone material was selected to conduct the large scale cross-section ultrasonic experiments, including the Non-rotary Ultrasonic Machining with free Abrasives (NRUSM), Rotary Ultrasonic Machining with free Abrasives (RUSM) and Rotary Ultrasonic Machining with fixed Abrasives (RUM). In the case of diamond tool utilized in the rotary ultrasonic processing, electroplating coating and powder metallurgy diamond tool were primary selected, but they have the drawbacks of the high tool were and low tool life. As is known, the brazing of monolayer of diamond tool possesses of the high protrusion height and strong bonding force between grits and substrate. It provides more swarf storage spaces to decrease the tribology among swarf, workpiece and tools. But, there were no reports on the rotary ultrasonic processing with brazing diamond tool, and few reports on the influence of tool end shape to ultrasonic processing. From these points of view, variety of work has been done on the choice of tool material, analyzing and optimizing design of tool matrix and fabrication of diamond tool at circumstance of vacuum status, which will make good preparations for the conduction of experiments.5. Based on the above work, critical attention was focus on the detailed design and analysis of the whole engine bed. Electrical energy transmission between the ultrasonic power supply and the spindle at a high speed level has been solved; Constant pneumatic force feed-up work table was developed. Proper Direct Current Power Supply and Direct Current Motor were selected to design the velocity modulation system, which can actualize the ultrasonic spindle system work steadily.6. Based on completion of the above works, three kinds of large scale cross-section ultrasonic experiment were carried out to the selected workpiece. The influences of different input parameters on the material removal rate and surface quality of the workpiece were studied. Constant static force and torque were tested during the process, at the same time, the topography of the diamond tool and workpiece were observed with a digital microscope, which will give a good explanation of the tool wear mechanism.7. In NRUSM experiments, as for the maximum MRR, there exists an optimal static load, namely 60 Newton, at the given condition of tool and its 25μm amplitude. Under the machining condition of constant 60 Newton static load, MRR increases along with the amplitude increasing, and also the value of surface roughness Ra increases.8. In RUSM experiments, because of the introducing of spindle rotary speed, MRR has a dramatically increases compared with the NRUSM experiment. But there exists a proper speed range of about 100-150 rpm for the giving tool. As for the maximum MRR, there exists an optimal amplitude 30μm in RUSM. Torque increases along with the increase of rotary speed, and decreases along with the tool amplitude increases. 9. In RUM experiments with brazing diamond tool, MRR has a notable increase with the improvement of rotary speed and amplitude. MRR with the intermittent matrix diamond tool is 2.5 times that of with continuous one. Moreover, its life has improved dramatically. Compared with the continuous matrix diamond tool, intermittent one has a lower torque.10. As for the tool wear mechanisms in RUM, wear form of diamond grit can be divided into five different kinds, that is whole crystal, micro fracture, macro fracture, fracture and polishing. The process of diamond wear has a big difference according to the different kind of tool. To continuous one, it has a large proportion of macro fracture and fracture diamond grits at the beginning of the process. But to intermittent one, it has a steady process of diamond grits wear at the earlier period. Polishing wear diamond grits will be in the highest flight at the later period.
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