Structural Analysis And Optimization Of Key Component Of Shaped Stone Saw-Milling Machining Center

With the development direction of high speed,high efficiency and precision of modem CNC machining equipment,the high rigidity of the machine tool structure and the lightweight design of moving parts have become one of the main contents of moden machine tool design.The static and dynamic characteristics of crossbeam and cutting spindle are related to the geometry precision and surface quality of the machining workpiece.The structural layout of the internal ribbed plates and the supporting structure of the spindle play a decisive role in its performance.Natural stone is a kind of typical hard brittle material,according to its special material properties and irregular physical components,which make special demands on its processing and equipping.Although there were some former research of the group:Shaped Stone Saw-Milling Machining Center?HTM50200?has obtained many technology breakthroughs,which gained Chinese patent gold medal and gold medal of the IEME and so on.However,the first batch of products used traditional gantry structure and casting bed,and its excessive self-weight and design margin increase the industrialization development cost.Saw-milling complex processing technology,which was based on the turn-milling machining technology,considering the physical characteristics of natural stone,through the rapid rotation of the saw blade,getting a new processing technology for higher cutting speed and machining efficiency,demanded higher static and dynamic characteristics in machining equipment.Under the support of the education department Yangtze River scholar innovation team project?IRT₁5R45?and National natural source foundation?51705341?,in this thesis,the structure design and the structure optimization of crossbeam and motorized spindle were studied,the main research were as follows:?1?Based on the analysis of shaped stone saw-milling machining process,the shaped stone saw-milling machining center was designed,and the GMC2010s type shaped stone saw-milling machining center was designed with five-axis CNC machining,which can realize sawing and milling of complex curved surface and surface of hard brittle stone,and other multi-process combined machining.?2?In this thesis,processing condition of the hard-brittle stone saw-milling machining load characteristics was analyzed by combining theory with experiment;Based on the mechanical analysis of main shaft and beam structure unit,using the design method of welding crossbeam structure based on ICM;Five structural schemes had been established for the analysis of the structure and layout of the interior ribbed plates.After comparison and analysis of beam model,the optimal model of the beam was determined.Compared to the traditional casting structure,the overall quality of optimized structure reduced by 24.18%,the static stiffness increased by 15.38%,and the natural frequency effectively avoids the rotation vibration frequency of spindle.The modal test analysis showed that the design of the beam structure was reliable and stable,and can meet the machining requirements.?3?Based on the sensitivity analysis of the saw-milling spindle structure key dimensions,the key dimensions of the motorized spindle structure were determined by multi-objective parameterized optimization The spindle structure design scheme of single factor index was obtained by index of static deformation,stress and quality separately;A mathematical model was established to optimize the stiffness of the spindle front and the parametric design was carried out.By using the Ansys,the optimal size group of the spindle structure parameters of saw-milling was obtained.The static stiffness of the optimized electric spindle increased by 13.4%and the natural frequency increased;The main shaft had a good rigidity when the rough machining?the frequency of sawing was 1780Hz?;The maximum working speed of spindle design was 1.2 ×104 r/min,far less than its low order critical speed,which can effectively avoid resonance.Based on the local modal analysis of the actual work,the rationality of the parameter optimization of the spindle structure was verified.