| The superficial mass of crossing bore has great influence on the useful life and assembly precision of machine parts. Burr problem of crossing bore is the main factor in affecting the surface quality, it belongs to the finishing process, and is a bottle neck of it.At present, there are many deburring machining methods, such as barrel deburring, vibration deburring, grinding deburring, injective deburring, electrochemical deburring, heating pulse deburring and so on. which all have their own advantages and shortages. Barrel deburring can damage and deform the machine parts surface; Electrochemical deburring requires the machine parts conductivity; Heating pulse deburring has high requirements on fusing point of machine parts, and so on. Therefore, new research about deburring method still to be continue.More and more attention now has been given to Ultrasonic machining in industrial machining area, and at the same time, its theoretical analysis and experimental research are also more and more thorough, To a certain extent, the technology has been more and more maturity. Machining principle of abrasive is complex, including impacting, micro-grinding and cavitation of suspensions. Ultrasonic machining is applied as assisted machining type.Aiming at the problems above, the ultrasonic machining method of removing the burrs on cross hole was put forward in this article. As a case,5mm hole were tested and studied. The difference between test apparatus and the traditional ultrasonic machining device is:artifacts directly connected with amplitude transformer, and the amplitude transformer directly excited workpiece, producing high intensity ultrasonic vibration. then the effect of grinding and collision between the workpiece surface and the abrasive was producd by the ultrasonic vibration, coupled with the complete cavitation effect of liquid-solid two-phase flow, realizing the processing of the burr removal to the cross hole, at the same time, the surface roughness of the inner surface of cross hole was reduced, which significantly improved the quality of the surface matching, surface, sealing, surface wear resistance, cleanliness, and the service life was prolonged. The main research contents are as follows:(1) The formation mechanism of burrs on small holes and the morphology, size of burr were analyzed and components of ultrasonic machining system and the working principle of equipment were introduced.(2) The finite element analysis of ultrasonic transformer with equal in length was made, and change rule between the reduction coefficient β of the resonance frequency and area ratio N and diameter ratio α was discussed, then compared to the existing experimental results, it is concluded that the finite element method in the design of the amplitude is of high reliability, then ANSYS modal analysis and harmonic response analysis of the conical horns which has been theoretically calculated was simulated, getting the actual resonance frequency and the amplitude response of the conical horns Verifying the accuracy of the design, laying a solid foundation for adjustment of the experimental equipment.(3) Take5mm hole of45#steel for example, experiment of removing the burrs on cross hole has made using the method of the ultrasonic machining. Two kinds of parameters were chosed in the test, including time and abrasive particle size. T hen the influence of the test parameters to processing effect was explicit.(4) On the basis of the finite element simulation on ultrasonic machining of brittle materials and the finite element simulation of metal cutting, finite element model of grain impacting burrs was established and the form change of the burrs impacted by abrasive was observed micro and intuitively. First step of establishing the finite element model of deburring was put forward. |
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