Structure Analysis And Motion Accuracy Research Of Frame Grinding Machine

With the inreasement of the myopia group,the glasses have become indispensable to people's life necessities,people put forward higher request for the appearance quality of the glasses,and promoted the rapid development of the glasses processing industry,the rise of the polishing grinding equipment resulted in the further replacement of the traditional way of manual polishing.At present domestic glasses frame processing factories faced with many problems,such as low efficiency and poor product consistency,most domestic factories existing grinding machine tool machining process trival,low degree of automation,most of the process still rely on artificial to complete,in order to keep up with the requirements of the international high-end market,and break the monopoly of foreign high-end equipment,developing the new frame polishing equipment become an important direction.This paper introduced the development status of automatic polishing equipment at home and abroad,for plastic glasses frame processing technology,we studied a variety of polishing solution,and designed a kind of high efficiency,high-precision 4-axis glasses frame grinding machine,the machine could realize continuous grinding on the surface and lateral surface of the 6 groups of plastic glasses frames,and it has achived high accuracy.We designed the mechanical structure of machine tool and control scheme,including institutions such as the jig,turntable,linear modules and the shafts of the machine tool,selected the key parts of the machine tool,including the servo motor and ball screw,checked and ensured the movement precision of the machine tool,determined the “PC + motion control card + servo motor” control scheme.To confirm the key dimension parameters,further optimization for machine tools was carried out,the error model of the 4-axis polishing machine tool is built up by using multi-body system theory,the integrated error of machine tool as the optimization goal,we designed the orthogonal experiment and simulate the experiment,and analyzed the influence of the size variables to the comprehensive error of NC machine tools,later the key parameters of the machine were determined.After establishing finite element model of the polishing machine tool,modal analysis was carried out to the turntable and triaxial linear module,we got the first six order natural frequencies of the turntable and triaxial linear module,which provide the basis for the determination of motor speed.On the basis of statics analysis,the stiffness of machine tool is verified.Through the analysis of the forming principle of machine load error,a load error calculation method was proposed,based on the finite element model of three axis module,we obtained the deformation of the guide rail contact surface,and get the error of machine tool by caculation method.We designed a scheme to measure the error element and introduced the principle of identification of nine line method,later we used a laser interferometer to measure the positioning error of three straight axis of the machine tool,the repetitive positioning error of the straight axis is measured with a dial gauge and rotation repetitive positioning error was measured by electronic Angle gauge,and verified the rationality of the accuracy of the machine tool,we carried out grinding experiment,and used binocular microscope to observe the workpiece surface of the frames before and after polishing,by the microscopic image,we verified the feasibility of grinding machine scheme.In this paper,the research work provided practical guidance to the design of high precision CNC machine tools,the research has great value to the automatic grinding equipment.