| IntroduceThe project had been supported by National Natural Science Foundation of China.With the development of science and technology, more and more high-technology products are been turned out. Holes have been widely used in aerospace and astronautics, automobile, mechanical engineering, and other manufacturing industry. There are many unconventional machining technologies to make holes, such as Electronic Discharge Machining (EDM), Ion Beam Machining (IBM), Laser Beam Machining (LBM), etc., which are different in the mechanics. But the application of those methods is limited by the workpiece material, required precision, productivity, production cost, and can't be widespread availability.At the present time, the method, which is extensive used and have the powerful practicability, still is drilling. But the conventional drilling can't meet the new requirements because of the bad hole quality, the inefficient. Furthermore, more and more investigations on vibration drilling have indicated that as a new drilling technology, vibration drilling not only can decrease the cutting force but also improve the machine performance. The vibration drilling presents its predominance and arouse the interest of scholars. Vibration drilling as an unconventional machining technology is based on the vibration cutting theory. In vibration drilling, vibration unit will produce a controllable relative vibration between the drill and the workpiece. The vibration drilling mechanics is different from conventional drilling. According to the properties of workpiece material, some variation parameters vibration drilling methods are appeared, which is first proposed by Professor Wang Li-jiang and became a new subject of vibration drilling research field. The variation parameter vibration drilling include the following method: varying parameters vibration drilling in three-segment for one kind material, the multiple variation parameter vibration drilling for laminated materials, the hybrid variation parameters vibration drilling for fiber reinforced composite materials.Phase-Difference is a very important concept in vibration drilling. Different Technologic effect can be found because of different Phase-Difference. Phase-Difference is hardly mentioned at the old study on vibration drilling, so it is very necessary to study the influence laws of Phase-Difference to vibration drilling .2.the movement theoretic of vibration drillingIn the paper, the variational thickness characteristic,the dynamics axial cutting thickness, cutting graphics, separation characteristic are introduced, a concept of separation-coefficient is presented, which is the ratio of cutting time and the vibration cycle. By the analysis and calculate of the computer program, it is found that the relation curves between K and ( is periodic, symmetrical and having many peak values. The cycle is 2( and the symmetry axial is (=( in one cycle. in one cycle, the number of peak increase graduadly with the E(Fig.2-8).The influence law of Phase-Difference to rear angle is obtained by means of variational angle characteristic。In a word ,we can optimize the vibration parameters and cutting parameters according to the changing law of K-φ.3．The effect of Phase-Difference to the thrust of vibration drillingThe thrust is a important information which reflect the dynamics course of cutting. It is very complex between the workpiece and cutter. In the text, we take average thrust as the measure target of the experiments.A lot of experiments are perform on the copper sheet that the thickness is 2mm to investigate the exit force, the mean force, The results show that e exit force is decreasing with the frequency and the mean force is correspondence with separation-coefficient.4．The influence of The Phase-Difference to the Technologic effect on vibration drilling It exist the dynamic characteristic of "bore-separate-attenuate-rebore" during vibration drilling, so separation-coefficient affect the deflation of the drill point greatly, more separation time c... |
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