Towards a new definition of areal surface texture parameters on freeform surface: Re-entrant features and functional parameters

• Published in: Measurement : journal of the International Measurement Confederation 2019-07, Vol.141, p.442-459
• Main Authors: Pagani, Luca, Townsend, Andrew, Zeng, Wenhan, Lou, Shan, Blunt, Liam, Jiang, Xiang Qian, Scott, Paul J.
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Approximation; CAD; Computer aided design; Freeform surface; Hydrophobic surfaces; Measurement; Measuring instruments; Parameters; Re-entrant features; Shape recognition; Studies; Surface characterisation; Surface layers; Surface roughness; Texture
• ISSN: 0263-2241; 1873-412X
• DOI: 10.1016/j.measurement.2019.04.027

•A method to compute the hybrid and functional roughness parameter is presented.•Two surface reconstruction methods are investigated: Bezier surfaces and triangular meshes.•The comparison with the texture parameters defined in the ISO 25178-2 is analysed.•The method can be applied to meshes measured using computed tomography.•The proposed method is suitable for additive manufacturing parts. Characterisation of freeform surfaces is an increasingly importance area of metrology. Currently the characterisation of surfaces is performed using data that can be represented by a height map. Modern measurement devices allow the acquisition of surfaces with complex shapes that cannot properly be analysed using the current texture parameters definition. In this paper a method to characterise both freeform surfaces and surfaces with re-entrant features is proposed. Two surface approximation methods are investigated: triangular mesh and Bézier surface. The proposed method will be compared with a method able to extract the ISO 25178-2 areal texture parameters from a triangular mesh.