A brand new direct and adaptive slicing approach is proposed, which canapparently improve the part accuracy and reduce the building time. At least two stages are includedin this operation: getting the crossing contour of the cutting plane with the solid part anddetermining the layer thickness. Apart from usual SPI algorithm, slicing of the solid model has itsspecial requirements. Enabling the contour line segments of the cross-section as long as possible isone of them, which is for improving manufacturing efficiency and is reached by adaptively adjustingthe step direction and the step size at every crossing point to obtain optimized secant height. Thelayer thickness determination can be divided into two phases: the geometry-based thicknessestimation and the material-based thickness verifying. During the former phase, the geometrytolerance is divided into two parts: a variety of curves are approximated by a circular arc, whichintroduces the first part, and the deviation error between the contour line in LM process and thecircular arc generates the second part. The latter phase is mainly verifying the layer thicknessestimated in the former stage and determining a new one if necessary. In addition, an example usingthis slicing algorithm is also illustrated.
Numerical instabilities are often encountered in FE solution of continuumtopology optimization. The essence of the numerical instabilities is given from the inverse partialdifferential equation (PDE) point of view. On the basis of the strict mathematical theory, a novelmethod, named as window filter and multi-grid method, which solves the numerical instabilities, isproposed. Convergent analyses and a numerical example are presented.
Guo Dongming Wang Xiaoming Liu Zhenyu Department of Mechanical Engineering，Dalian University of Technology， Dalian 116023，China
