| Although it can improve the turning efficiency,it is also easy to produce excessive deformation and vibration under the internal intermittent cutting and external environmental excitation,which will affect the accuracy of the workpiece,therefore,it is necessary to analyse the static and dynamic characteristics of the machine tool.In this paper,the overall design of the machine tool is firstly carried out,and then the static characteristics of the cutting part of the machine tool and the whole machine structure are studied and analysed based on the finite element method to verify the deformation and stress of the turning position and the whole machine under the action of cutting force.Finally,a multi-objective optimisation and topology optimisation design of the spindle box is carried out to improve the static and dynamic performance and structural lightweighting.The main elements of this research are as follows.(1)The overall structural design of the machine tool,according to the actual machining requirements,determine the machining process flow,calculate the production time and capacity,and design and calculate the cutting force and fixture;the structural design and calculation of key components,mainly including the inverted turning drive system,screw selection,positive turning drive system and tool holder structure,and complete the structural 3D modelling in Solidworks.(2)Static analysis of the cutting parts of the machine tool and the whole machine to verify the local cutting position of the machine tool and the whole machine has a certain resistance to external load damage and deformation,static analysis to provide reference for the identification of weak links.(3)Dynamic analysis of the machine tool,the solution to obtain the results of the modal analysis and harmonious response analysis,to find out the causes of resonance of the machine tool due to intermittent cutting,to propose improvement plans and verify the results,and finally determine the improvement plan.(4)Static and dynamic verification of the spindle box and the bed,after analysis to determine the design of the spindle box is too conservative,multi-objective optimization and topology optimization of the spindle box design,verification before and after the optimization of the maximum equivalent force of the spindle box reduced by 2.68MPa,the inherent frequency increased by 7%-22%,the mass reduced by 24kg,to achieve the purpose of lightweight and improve the static and dynamic performance. |
