The Finite Element Analysis And Multi-objective Optimization Of The NC Boring And Milling Machine Bed

The design of NC machine, mostly based on traditional analogy and staticperformance in current, induces some shortages, such as irrational structure, highweight and bad dynamic performance. Modern optimization method is introducedinto the design of TK6920NC Boring and Milling machine to meet the goal ofbetter dynamic performance of crane jib and lighter structural weight, under thecondition of structure strength and stiffness.The Solid Modeling of NC machine has been made in the software Solid works,and the bed has been analyzed when slide’s in different position of the bed.The static analysis of the bed’s simplified model is analyzed into the finiteelement analysis software ANSYS. From the results of the analysis we know thatthe bed’s strength well and deformation is very small. The bed anti-vibrationcapacity is strong and machining accuracy is relatively high.The first six order modal shape and natural frequency of bed are gained fromfinite element mode analysis. The analysis results show that major factors whichobviously affect the performance of the bed are low-order natural frequencies. Themajor distortion of the bed is bending distortion especially in the middle of twoconnected parts. So it is needed to adjust the thickness of rib plate to improve thebed’s seismicity.Construct the response surface model by orthogonal experiment design, andthen take improving the bed’s seismicity and Structure Lightweight as theoptimizing objective. At last perform the multi-objective optimization design ofbed’s structure, the quality of the bed after optimized is reduced and the first fourorder modal shape frequencies are improved.Taking an optimization design of the bed from finite element analysis theoryand multi-objective optimization theory, it can improve the CNC machine precisionand provide a theoretical basis and practical production for design andtransformation of the machine bed.