Design And Optimization Of Micro Mobile Gantry CNC Milling Machine Ontology Structure

Using the small machine tool to manufacture medium and small parts can save resources and energy as well as the manufacturing space, which meets the demands of green manufacturing about energy conservation and environmental protection, and therefore, the research and development of miniature machine too has received the widespread attention. This paper put the micro mobile gantry CNC milling machine as the research object, a preliminary design of the milling machine structure was made, using the finite element method made an analysis about dynamic and static characteristic analysis, and completed structure optimization of key components;the micro milling machine prototype was designed and manufactured according to the results of the finite element analysis and optimization and completed the accuracy detection, studied the actual processing performance of the micro milling machine prototype.In this paper, based on machine typical processing conditions micro of the milling machine, the preliminary design of miniature mobile gantry milling machine main transmission system、 feed system and foundation has carried on, and using the 3 D software to establish the model of micro milling machine ontology structure. The machine shape dimension is 900 mm × 700 mm ×650 mm, working stroke is 400 mm × 500 mm × 150 mm, prototype machining accuracy is 0.02 mm.Choosing one of the typical working condition, the statics analysis of the milling machine was completed, studied its stress and displacement about knife site and center of the table in four different processing position, and analyzed the machine’s static stiffness; integration finite element model of a milling machine guide rail sliding block is established using spring-damping element, the whole machine 3 D model was simplified and machine finite element dynamic analysis model is established. The modal analysis of the whole machine was completed, and obtained first ten order natural frequency and main vibration modes; through the harmonic response analysis, excitation response curves about the knife node and workbench center under typical working conditions of cutting force excitation response curve were obtained. Through the static and dynamic characteristics analysis of the machine, the weak link of the machine tool design was found.According to the results of finite element analysis, based on the principle of topology optimization, putting the minimum strain as the objective function, column volume as design variables, the optimization design was carried out on the micro milling machine column; Adopting the method of orthogonal experiment, put the maximum displacement undering the weight of table as the optimization goal, T slot size, groove spacing, the thickness of the workbench, and the workbench supporting area as design variables, by the optimized design to select the optimal results; Finally the machine dynamic performance has obviously improved after optimization is proved by the harmony response analysis and the modal analysis.According to the structure design, the micro mobile gantry CNC milling machine prototype was made, through testing and adjusting the geometric accuracy of the micro milling machine, to ensure deviation about each axis’ s straightness and perpendicularity is less than 0.002 mm/M. Machining specimen tests, according to machine tool processing accuracy of 0.02 mm or so, meet the requirements of the precision machine tool design. By testing the standard specimens which was processed by the machine tool, the error remained at around 0.02 mm, to fulfill the design requirements of the machine tool.