188宝金博页面版

5-Axis adaptive f l ank milling of f l exible thin-walled parts basedon the on-machine measurementNuodi Huang, Qingzhen Bi, Yuhan Wangn , Chao SunState Key Laboratory of Mechanical System and Vibration, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR Chinaa r t i c l e i n f oArticle history:Received 26 November 2013Received in revised form8 April 2014Accepted 8 April 2014Available online 18 April 2014Keywords:Adaptive machiningThin-walled partOn-machine measurementEnvelope surfacea b s t r a c tDeformation of the part and cutter caused by cutting forces immediately affects the dimensionalaccuracy of manufactured parts. This paper presents an integrated machining deviation compensationstrategy based on on-machine measurement (OMM) inspection system. Previous research attempts onthis topic deal with deformation compensation in machining of geometries in 3-axis machine tools only.This paper is the f i rst time that concerned with 5-axis f l ank milling of f l exible thin-walled parts. Tocapture the machined surface precision dimensions, OMM with a touch-trigger probe installed onmachine's spindle is utilized. Probe path is planned to obtain the coordinate of the sampling points onmachined surface. The machined surface can then be reconstructed. Meanwhile, the cutter's envelopesurface is calculated based on nominal cutter location source f i le (CLSF). Subsequently, the machiningerror caused by part and cutter def l ection is calibrated by comparing the deviation between themachined surface and the envelope surface. An iteration toolpath compensation algorithm is designed todecrease machining errors and avoid unwanted interference by modifying the toolpath. Experiment ofmachining the impeller blade is carried out to validate the methodology developed in this paper. Theresults demonstrate the effectiveness of the proposed method in machining error compensation.& 2014 Elsevier Ltd. All rights reserved.1. IntroductionIt is desirable and indispensable to have thin-walled parts likeimpellers and monolithic spar-ribs in many application areas suchas aerospace, automobile and energy industry. Those parts oftendesire for high surface prof i le accuracy. However, inf l uenced bythe f l exibility of part and cutter, unwanted dimensional errors cannot be avoided. To this end, the precision adaptive machiningmethod with high eff i ciency is of great value.In recent years, f l ank milling has been widely applied formachining of such thin components. With the application of f l ankmilling, the machined surface quality and machining eff i ciency canbe improved greatly compared to end milling. Many methods wereproposed for f l ank milling toolpath planning [1–5] and they havemade signif i cant progresses. However, those toolpath planningmethods as well as the existing CAD/CAM software like MAX-PAC,HyperMILL, UGS NX and so on only focus on reducing thedeviations between the ideal toolpath envelope surface and theinitial designed surface. They treat the part and cutter as rigidbodies and seldom consider the def l ections of the part and cuttercaused by cutting forces during machining. As a result, the realmachined parts often represent the state of undercut or overcut.Some researchers have noticed this practical issues and techniqueshave been proposed to handle it.To eliminate the machining errors caused by part and cutterdeformation, active methodologies are validated, which can besummarized into four subdivisions:(a) Improved machining strategy. Smith et al. [6] used thesacrif i cial structures to make machining process more insen-sitive to the thinness. Erdim [7] proposed feedrate schedulingstrategies to limit the cutting forces. Those strategies canimprove the machining accuracy for some special structuredparts, but often associate with a sacrif i ce of productivity. Thesubject is limited to process optimization and advancedabilities of CNC machine tools have not been considered [8].(b) Real time compensation. Special NC controller was designed tocontrol the cutting forces by tilting the cutter direction [9,10].However, it requires the modif i cation of the machine andcontrol system hardware [11] and has not been implementedin industry.(c) Off-line error prediction and compensation. Numerical meth-ods are currently used to predict and simulate the cuttingforces as well as the part and cutter deformation duringmachining. Chen et al. [12] established a dynamical model topredict and compensate the deformation for multilayerContents lists available at ScienceDirectjournal homepage: www.elsevier.com/locate/ijmactoolInternational Journal of Machine Tools & Manufacturehttp://dx.doi.org/10.1016/j.ijmachtools.2014.04.0040890-6955/& 2014 Elsevier Ltd. All rights reserved.n Corresponding author. Tel.: þ86 2134206800.E-mail address: yuhan_wang0306@163.com (Y. Wang).International Journal of Machine Tools & Manufacture 84 (2014) 1–8基于机内测量的柔性薄壁零件五轴自适应侧铣