| With people’s aesthetic concepts changing and the manufacture process standardimproved, individuated products of complicated surfaces are used increasingly in productionand daily lives. On the other hand, competitions in the global product market require themanufacture industry shortens the design and manufacture cycle. Therefore, it is verynecessary to research the rapid design and manufacture technology of complicated surfacedproducts. Additive Manufacturing owns an obvious advantage in respect of processingproducts of complicated surfaces. Forward Design and Reverse Design are capable of helpingprovide Additive Manufacturing for complicated surfaces with suitable CAD models. Thispaper is aimed at the research on the crucial technology of rapid Forward/Reverse Design forcomplicated-surfaced products. Besides, based on CAD models of Forward/Reverse Design,three data processing methods of Additive Manufacturing for complicated surfaces areproposed. According to what is mentioned above, the main content and results of this paperare as follows.（1）Additive Manufacturing for complicated surfaces. For the sake of improving,thedesign speed and accuracy and solving the crucial problems on rapid Forward Design ofproducts of complicated NURBS surfaces, a reuse method of partial features of NURBSsurfaces is proposed. First of all, the recognition and extraction algorithm of feature shapes isproposed. Secondly, the principals and methods of partial feature installation are drawn up.Afterwards, copy and paste of partial shape features are finished. Finally, the joint andconstruction algorithm of transition surfaces is proposed in order that continuous and smoothjoint satisfying G2between two adjacent NURBS surfaces is realized. It is shown inaccordance with the simulation result that reused features have good geometric properties.（2）Additive Manufacturing for complicated surfaces. For the purpose to guaranteedesign rapidity and accuracy and solve the crucial problems on Rapid Forward Design ofproducts of complicated STL surfaces, mathematic models for The Extended Approximationof curves and surfaces are set up. Above all, mathematic models of curve reconstruction basedon The Extended Approximation are established. Then STL surface reconstruction algorithmbased on The Extended Approximation is presented, which is able to well ensure continuityand smoothness of STL surface reconstruction. Finally, the reconstruction experiment onoutline curves of plane cams and surfaces of bumpers is carried out to test and verifyspeediness and the precision of the Extended Approximation algorithm.（3）Aimed at rapid Forward Designed products of NURBS complicated surfaces and in the way of increasing shaping accuracy and efficiency, a comprehensive algorithm ofmulti-strategied adaptive slicing for Additive Manufacturing is presented. Firstly, it is raisedthat slice thickness depends comprehensively on contingence angles of the points in verticalprofile curves and the area changes of adjacent slices. Plus, horizontal slice outline curvereconstruction algorithm based on Clothoid curve models is proposed by way of making surethat interpolation speed of follow-up numerical control machining is constant. It is proved bypractical processing examples that slicing efficiency of the comprehensive adaptive algorithmis higher and after being shaped, complicated-surfaced products owns great fabricatingaccuracy.（4）Aimed at rapid Reversed Designed products of STL complicated surfaces, aslice-optimizing processing algorithm for Additive Manufacturing is proposed for the purposeto increase shaping accuracy and efficiency. For the first part, a stepwise refined slicingalgorithm in adaptive slices is proposed so that horizontal slice thickness can be optimized. Inaddition, the horizontal outline curves are reconstructed by means of the The ExtendedApproximation algorithm. Again, the recognition algorithm of supporting regions based onslice Boolean operation is proposed. In the end, feasibility and precision of this algorithm aretested and verified by practical fabricating examples.（5）Surfaced products of dimensional point cloud models based on rapid ReverseDesign. By way of increasing shaping accuracy and efficiency, the IDS (Inverse DistanceSquare) adaptive direct slicing algorithm for Additive Manufacturing is presented. For thefirst place, a new idea about direct slicing of dimensional point cloud data is raised. After that,the IDS adaptive direct slicing algorithm is proposed and slicing accuracy of this algorithm ishigher. Additionally, in curve contour reconstruction of the vertical projection-constructingplane,The Extended Approximation extrapolated models based on point clouds are set up.Finally, the angle error method and bow height error method are made use of to achievehomogenisation and refinement of curve reconstruction and profile data points. Then higherprecision and efficiency of this algorithm are tested and verified by practical fabricatingexamples. |
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