In this paper,the key technology for five-axis NC programming manufacturing large sculptured surface in hydro turbine's blades is introduced,which includes establishing 3-D model,the tool path generating,cutting simulation,machining process simulation and post-processing in the programming.

As Hydro turbine blade is a very complex body closed by sculptured surfaces and the operating condition of the runner is also very complicated, traditional research way was combined the simplified theoretical analysis and model test.

Surface reconstruction plays an important role in many fields such as design of car bodywork, cartoon facture about sculpture surface of human faces and 3D reconstruction of medical images etc.

With an optimizing surface triangulation as result, this algorithm is suitable for surfaces of arbitrary topology, including nonorientable ones, hence can be applicable to visualization in scientific computing, sculpture surface modeling, and reverse engineering.

Firstly, starting with restriction of occluding contour, based on the traditional volume intersect to realize the full expression of the restriction by using surface distortion technology, then one simple way was get for modeling of sculpture.

This paper introduces the key technologies in programming of NC 5-axis machinin g for large sculpture surface of Francis hydroturbine blade including 3D modelli ng, tool path generation, cutting simulation, processes simulation, post-pr ocessing, etc.

In such instances, it often becomes necessary to model the part using compound surfaces that consist of several individual sculptured surface patches.

Feature based quadrilateral mesh generation for sculptured surface products

A successful approach to the generation of quadrilateral surface meshes for finite element analysis of sculptured surface products is presented.

A procedure, based on this approach, which generates well formed meshes on sculptured surface products is described using a hollow golf club head as an example.

Determining the cutting conditions for sculptured surface machining

A new algorithm is Proposed for displaying objects consisting of Curved Su- rfaces and Plane faces with hidden lines removed. The surface of objects disp-- layed are approximated with faects and represented uniformly as polygons. The algorithm Cheeks with a few simple operations each edges against the polygons to determine the visibility. On reguest either the picture with gaid structure or profile figureis clisplayed.

This paper discuss a new method of calculating the minimum distance between two sculptured sur-faces.Using optimization method,the problem of collision detection between two convex surfaces is re-solved.The efficiency and realizability of this approach are analyzed.This paper is supported by exam-ples in it.

In the field of NC programming,it is a difficult problem to ensure that no interference occurs be-tween cutter and surface to be machined(SM).Starting from the Critical Boundary Constraint Method(CBCM) proposed in 1991 by Zhang et al[4],the authors in this paper present an extended CBCM thatcan deal with how to avoid interference between any cutter and SM in multi-axis cutter locationoffsetting.The main points of the extended CBCM are as follows:(1)By using CBCM,the initial cutter location and axis direction...

In the field of NC programming,it is a difficult problem to ensure that no interference occurs be-tween cutter and surface to be machined(SM).Starting from the Critical Boundary Constraint Method(CBCM) proposed in 1991 by Zhang et al[4],the authors in this paper present an extended CBCM thatcan deal with how to avoid interference between any cutter and SM in multi-axis cutter locationoffsetting.The main points of the extended CBCM are as follows:(1)By using CBCM,the initial cutter location and axis direction are so determined that the cuttingedge of the cutter is sufficiently near to SM.(2)The cutter is approximately represented by a finite number of spheres,which are tangent to the in-ternal surface of cutter and whose centers are taken as sample points for calculating the minimum dis-tances between the cutter and SM.(3)The above-mentioned minimum distances are the data needed for so adjusting the cutter as to sat-isfy given interference tolerance limits.The extended CBCM appears to be better in comparison with two other methods.The polyhedral machining method of Duncan et al[1]considered only one sphere at the head ofballend cutter whose axis is fixed in one(Z) direction.While,for finding minimum distance between cutterand SM,extended CBCM considers as many spheres as required and axis of cutter may be in anydirection,without subdividing SM into polyhedral of triangles.The well known APT4/SS‘swalf’method only ensures that the cutter is tangent to SM at one sec-tion circle of the cutter,so interference may still occur at other points on the cutter.The extended CBCMessentially considers as many section circles on the cutter as required,and can process more complex inter-ference cases.