| Summary: | 碩士 === 國立虎尾科技大學 === 機械與電腦輔助工程系碩士班 === 100 === As precision cutting takes a key position in modern manufacturing industry, in addition to the tooling machines applied, designing and selecting cutting tools are extremely important steps. An indispensable process when it comes to precision conversion, boring usually is carried out with vibration as the boring-bar itself is mostly made of lower dynamic rigidity and it is the defect that keeps depth boring a less successful task. This study aims to establish a length-diameter ratio at 11 for the sake of reducing chatter sensible vibration in boring-bar. This article consists mainly of 2 parts; Part 1 is based on, through literature research, the results of boring bar parameters involved in past works before adding improvements of its structure and eventually, the simulation study by analytical software carried out using limited elements on ANSYS WORKBENCH. The purpose is to assure whether, by using different materials at the same time, rigidity could be improved, shaking and vibration could go reduced. The simulation analysis indicates that the newly developed boring-bar has an outer layer of S45C of , while the inner wrapping layer SKD11 of forming a new type of boring tool of a dual-layer construction, the same creates a static displacement of 0.192mm, which is less than the total displacement of 0.19385mm produced by an average boring bar structure. A further analysis of vibration modulus results in minor total displacement than that of boring bars of regular construction of new type numbered 1 to 6. The figures are taken as the best ones delivered from the test.
In Part 2, where the conclusions undergo a simulation analysis along with mean production of the new type of boring bar of two-layer construction. After a trial cutting, cutting conditions are set (which include rpm, cutting depth and cutting width)and the fineness-length ratio is used as a parameter in the comparison with boring-bar of regular construction. After analyzing the test figures using dynamic signal analyzer and acceleration gauge, it becomes clear that the new type boring-bar does improve remarkably in terms of radius total displacement area and workpiece surface roughness after cutting. The test itself makes a proper selection and combination of materials and, as the sectional area of the boring-bar is actually limited by mean working requirements, the newly designed boring bar does see its dynamic rigidity remarkably increase and, at the same time, displacement and chatter go down suggesting that the boring-bar referred in this study is successful when it comes to non-rattling effect in cutting.
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