Iso-level tool path planning for free-form surfaces

The aim of tool path planning is to maximize the efficiency against some given precision criteria. In practice, scallop height should be kept constant to avoid unnecessary cutting, while the tool path should be smooth enough to maintain a high feed rate. However, iso-scallop and smoothness often conflict with each other. Existing methods smooth iso-scallop paths one-by-one, which make the final tool path far from being globally optimal. This paper proposes a new framework for tool path optimization. It views a family of iso-level curves of a scalar function defined over the surface as tool path so that desired tool path can be generated by finding the function that minimizes certain energy functional and different objectives can be considered simultaneously. We use the framework to plan globally optimal tool path with respect to iso-scallop and smoothness. The energy functionals for planning iso-scallop, smoothness, and optimal tool path are respectively derived, and the path topology is studied too. Experimental results are given to show effectiveness of the proposed methods

Hidden curve removal for free form surfaces

Journal ArticleThis paper describes a hidden curve algorithm specifically designed for sculptured surfaces. A technique is described to extract the visible curves for a given scene without the need to approximate the surface by polygons. This algorithm produces higher quality results than polygon based algorithms, as most of the output set has an exact representation. Surface coherence is used to speed up the process. Although designed for sculptured surfaces, this algorithm is also suitable for polygonal data

Optimization Of Branching Structures For Free-Form Surfaces Using Force Density Method

Branching structures are mechanically efficient in supporting large-span structures, such as free-form roofs. To support a roof with a specified geometry, we present a novel shape and topology optimization method to find the optimal branching structure in this paper. In the proposed method, the branching structure is modelled as a cable-net, while the reaction forces from the roof are taken as external loads. The force densities of the members are the design variables. The optimal branching structure can be obtained by minimizing one of the several proposed objective functions. The shape of the branching structure represented by the nodal coordinates is determined by solving the linear equilibrium equations. The topology is optimized by removing the members with small axial forces and incorporating the closely spaced nodes. The cross-sectional areas can be easily calculated, if the allowable stress is assigned. Hence, it is very convenient to simultaneously optimize the cross-section, shape, and topology of a branching structure. Numerical examples show that this method can be easily applied to a 2D problem. For a 3D problem, the constraints on the reaction forces should be relaxed. Considering the roof supports as variables is also an effective solution for 3D problems

Checking and Measurement of Free Form Surfaces

Import 05/08/2014V diplomové práci je navržen a realizován postup programování měření tvarových ploch na 3D souřadnicovém měřicím stroji. Součást se skládá ze tří tvarových ploch, půlkoule, část plochy válce a jehlan. Předmětem měření jsou dvě shodné součástí vyrobeny dvěma metodami frézování. Tříosým a pětiosým frézováním. Nejprve je práce zaměřena na problematiku souřadnicových strojů, jejich základní rozdělení, z čeho se stroje skládají. Probrali volbu měřicích doteků a jejich využití. Dále je vypracován program pro měření jednotlivých ploch pomocí softwaru Metrosoft Quartis R6 a na závěr zhodnoceno srovnáním výsledků.The thesis deals with implemented the programming procedure contoured surfaces 3D coordinate measuring machine. The component consists of three shaped areas, half sphere, other areas cylinders and pyramids. The object of measurement are two identical part produced by two methods milling. Three-axis milling and five-axis milling. First, it is focused on the issue of coordinate machines, their basic division of what the machines are composed. Discuss the choice of styli and their use. It is developed for measuring individual program areas using the software Metrosoft Quartis R6 and finally assessed by comparing the results.346 - Katedra obrábění a montáževelmi dobř