Innovative Surface Merging Method for Generating Point-Based Skin Model Shapes Considering Processing Features
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Online ISSN 2005-4602 Print ISSN 2234-7593
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Innovative Surface Merging Method for Generating Point‑Based Skin Model Shapes Considering Processing Features Ci He1 · Shuyou Zhang1 · Lemiao Qiu1 · Zili Wang1 · Xiaojian Liu1 Received: 19 June 2019 / Revised: 21 July 2020 / Accepted: 26 July 2020 / Published online: 17 September 2020 © Korean Society for Precision Engineering 2020
Abstract Virtual prototypes have been appealing in the early design stage of computer aided tolerancing, because it is less expensive to evaluate and modify tolerances numerically. Derived from the machining processes, form uncertainties are simulated, controlled and analyzed in virtual prototypes using parametric and intuitive surface patches. The generation of a complete virtual prototype often involves combining surface patches with different patterns to one complete model. To overcome possible geometric defects in this process, a surface merging method is proposed in this paper. Skin Model Shapes is first introduced as the geometric foundation. The whole part surface is segmented based on the geometric shape and machining type. Then point-based patches are generated accordingly. Interpolation implicit surfaces based on radial basis function networks are constructed in patch boundaries based on spatial-constrained homogeneous transformation matrices. A feature augmentation process is then introduced to preserve processing features after resampling the blend patch. The proposed method is proved to be efficient in feature retaining as well as surface smoothing, through numerical experiments and analysis on an example mechanical part. The results show that the generated virtual prototype would become 62.5% more smooth while retaining a 91.6% feature similarity after using the proposed method. Moreover, the proposed method could preserve 174% more features at a cost of 9.0% smoothness than using a conventional modified trimmed filtering method. Keywords Processing features · Skin model shape · Computer aided tolerance · Surface reconstruction · Tolerance modeling
1 Introduction Virtual prototypes (also named digital mock-up, DMU) have shown considerable potentials in improving product performance, reducing fabrication cost, and shortening cycle time [1]. As an essential step and a prerequisite for computeraided tolerancing (CAT), dimensional and geometric tolerances are integrated in the virtual prototype to make it closer to reality, improve design accuracy and reliability [2, 3]. For a full investigation, a product tolerance model should involve all kinds of uncertainties, such as dimensional, positional, form tolerances, surface roughness, and fineness [4]. However, the lack of a generic model for simulating all kinds of form errors could cause local geometric defects when generating virtual prototypes for tolerance design. * Lemiao Qiu [email protected] 1
State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
A lot of works has been carried out over the past few decades
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