KINEMATIC APPROXIMATION OF RULED SURFACES USING NURBS MOTIONS OF A CYLINDRICAL CUTTER

作者: J. Xia , Q. J. Ge

DOI: 10.1115/DETC2000/DAC-14280

关键词:

摘要: J. XiaDepartment of Mechanical EngineeringState University New YorkStony Brook, York 11794-2300xia@design.eng.sunysb.eduQ. GeDepartment 11794-2300qge@notes.cc.sunysb.eduAbstractThis paper deals with the problem 5-axismachining ofruled surfaces. It is well known that a ruled surface may be effi-ciently machined cylindrical cutter using side millingprocess. This studies planning tool mo-tion for milling surfaces as kinematic approxima-tion problem. The goal to develop new method synthesiz-ing Non-UniformRational B-Spline(or NURBS) motion suchthat swept such cutterclosely approximates given surface. First NURBS used interpolate or approximate set discrete cutterlocations Then thedeBool control positions fine-tuned tominimize error between cylindricalcutter under and desired surface.In this way, represented by deBoorcontrol associated knot sequence opposed ahuge locations.1 IntroductionTo achieve high precision productivity requiredfor products manufactured CNC machining processes,new real-timeCNC servo-controllershave been proposed anddeveloped (see, example, Koren, 1997). A real-time5-axisinterpolator capable producing more accurate smoothersurfaces than off-lineinterpolator since position ori-entation are accurately interpolated along surfacein real-time. conventional machine tools use off-linein-terpolation method, which adopts constant orientation lin-early interpolates two orientations approximatedend-points. results in abrupt change orientationaround end-pointsand thus produces roughness around theend-points. off-linemethod also large inacceleration deceleration at each interval, inincreased non-uniformityand time. cur-rent approach path has focusedon obtaining representation path. In orderto realize full potential real-timeservo-controller, an an-alytic description needed provide thecontroller continuous locations velocity andacceleration information.The research explore methods planningtool paths Non-UniformRationalB-spline(or motions. focus present paperis on 5-axismilling cut-ter’s edge, process. Compared bottom-edge process, process highly advan-tageous it allows significant reduction time,and therefore cost.Sincethe location (or positionand orientation) cylin-drical can defined axis cylinder, ruledsurface cylinder defines pathfor Thus plan-ning 5-axissiding sur-face studied “offset” ofthe original Considering atwo-parameterfamily points, then its normal offset surface1 Copyright 2000 ASME

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