NC machining verification algorithm based on the STL model
- PDF / 1,457,280 Bytes
- 9 Pages / 595.276 x 790.866 pts Page_size
- 92 Downloads / 187 Views
ORIGINAL ARTICLE
NC machining verification algorithm based on the STL model Ying Miao 1,2 & Xiaowen Song 3 & Jun Wang 1,2 & Zhonghua Lu 1,2 Received: 29 April 2020 / Accepted: 31 July 2020 # Springer-Verlag London Ltd., part of Springer Nature 2020
Abstract An algorithm to assess the deviation of a machined workpiece model for a nominal part of the stereolithography (STL) modelbased numerically controlled (NC) machining verification is presented, which is inspired by several algorithms used for evaluating the difference between two triangular meshes of similar shape, and some improvements are made. First, each triangle of the machined workpiece model is sampled under a user-defined sampling step δ. Then, the signed distance between each sample and the nominal part is computed to obtain the maximal error, minimal error, and mean error between the two STL models. Finally, a background grid is constructed to quickly search for the triangle closest to the sampling point. The experimental results demonstrate that the accuracy can be improved by sampling all the triangles, including those too small to be sampled under the current sampling step δ. The efficiency can be increased by applying a background grid, and the undercut and overcut areas can be easily detected by coloring the machined workpiece model according to the signed distance associated with each sample. Keywords NC machining verification . STL model . Sampling step . Signed distance . Background grid
1 Introduction NC machining simulation, which simulates and evaluates the actual NC machining process via computer graphics, has become an important step in modern manufacturing. By simulating the machining process prior to the actual cutting operation, inefficiency and errors in the tool path can be reduced and corrected at the programming stage. NC machining simulation technology contains two aspects: material removal process simulation and NC machining verification. The material removal process simulation realized via consecutive Boolean subtractions between the updated workpiece and the cutter swept volume is used to detect collisions and predict the final workpiece shape. NC machining verification
* Xiaowen Song [email protected] 1
Mechanical Institute of Technology, Wuxi Institute of Technology, Wuxi 214121, China
2
Jiangsu Intelligent Production Line Technology and Equipment Engineering Research Center, Wuxi Institute of Technology, Wuxi 214121, China
3
State Key Laboratory of Fluid Power and Mechatronic System, College of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China
algorithms are used to compare the geometrical differences between the simulated workpiece and the nominal part and to estimate whether the difference is within the allowable tolerance zone. NC machining simulation methods can be categorized into four major approaches according to the workpiece representation model, including the solid-based approach, object space-based approach, image space-based approach, and hybrid approach. In the solid-based approach, the
Data Loading...
