| The design and processing based on mathematical equations deduction of spiral surface, which is a representative of complex surface, is utilized for a long time. But the method based on mathematical equations is difficult to use because of the complexity to derivate and calculate the equations. CAD technology is another solution method. However, the usage of CAD is mainly focused on the simulation of the movement of machining, and the numerical extraction potential of CAD is ignored. In order to improve this status, a new CAD method to obtain the profile of the tool of spiral surface based on manufacture theory is put forward in this thesis. Combining with the advantages of numerical calculation, entity modeling and plot capability of computer, the functions of tool profile data extraction, curve fitting and error evaluation based on GPS(dimensional geometrical product specification and verification) theory are realized. Besides, the core technology and theory of this method is also researched deeply.In view of this situation, this thesis on the basis of thorough research in the traditional theory and design method take full advantage of the computer in the area of numerical calculation, the solid model and drawing, proposing a new CAD method of processing spiral surface with the forming cutter profile and tool profile data extraction, curve fitting and error evaluation. Furthermore, key theory and related technical problems have been thoroughly explored.The research content can be divided into the following three parts. Firstly, the paper based on the mechanism of spiral surface generated and processed systematically analyzes the feasibility of generating tool profile processing spiral surface according to helicoids end curved shapes using SOLIDWOEK. Then, three CAD methods forming cutter profile with which to process spiral surface are put forward, that is Boolean operation,slice method and radius method, further,the theory of every method to getting tool profile is introduced in detail.Scoendly, based on the API function offered by varkon, two methods of data extraction which are extraction-point and extraction-curve are put forward, realizing data point extraction in Sketch Points,subobiect way of Sketch Segments and curve fit method,then, these three ways are compared. Then, based on uniform b-spine curve fitting and non-uniform b-spine curve fitting, completed tool cut curve is fitted. Thirdly, to assess the data from tool curved shapes, combining with two methods for solving error in normal direction of fitted curve, which is method of solving equation and segment solution, error evaluation of the cutting contours of the tool is proposed based on error evaluation theory of GPS, according to the results from the equation of section profile of cutter. Meanwhile, the whole system software is completed by using Solidworks 2007.To validate the feasibility and accuracy of various algorithm and related methods proposed in this paper, take generation process of machining tool with male rotor of screw pump for instance, sectional contours of cutting tools and error estimation of the results in all manner of ways are completed. The results show that Boolean operation is unfit for the requirement of the manufacturing, as the runtime of which is long and the results are inaccuracy, but it can qualitatively apply to simulation of CAD. In contrast, slice method and radius method can get better results. Theoretic analysis and experimental results indicate that, using CAD technology to complete tool design of spiral surface is completely feasible. This thesis not only makes the engineering and technical personnel cast off deducing complex formula, but offers new ideas and feasible method for machining complex profile. |
PDF Full Text Request