結合STL三角網格與DXF公差資訊之電腦輔助檢測技術系統發展

The study of Computer Aided Inspection about combining STL Triangular Mesh with tolerance of DXF information

吳宗諭(Zong-Yu Wu)

指導教授 ： 賴景義

國立中央大學/工學院/機械工程學系/碩士(2006年)

摘要

品質檢測一直是產品生產過程中，不可缺少的部份，產品之檢測發展更需要隨著設計製造的腳步而進步。產品檢測雖然包含許多項目，但尺寸的檢測為最主要的項目。因此本研究目標在於結合CAD模型系統與DXF藍圖系統簡化自動化檢測之流程。

主要研究重心在於發展電腦輔助檢測之基本原理與演算法。研究內容包含如何有效率處理DXF格式資料結構，並簡潔說明由AutoCAD所制定DXF格式，特別提到圖形元素之尺寸標註說明，可以經由解析DXF藍圖格式，獲得尺寸與公差資訊。透過STL三角網格平行切層處理，可以得到CAD模型在二維平面截面點資料，經由座標轉換處理，將CAD模型與藍圖資料正確對應。電腦輔助檢測將CAD模型與藍圖資料結合在一起，針對藍圖檢測規劃項目自動化檢測，最後將CAD模型點資料根據設計藍圖尺寸公差規劃自動化公差分析。

關鍵字

圖形交換文件 ； 三角網格 ； 電腦輔助檢測 ； 座標定位

並列摘要

Quality inspection has been an indispensable part in the production process all the time. The technique of inspection has to be improved in order to keep up with the development of manufacturing. In spite of many kinds of inspection that should be implemented in a product, the dimension inspection of the product is still the most important. For this reason, the objective of this study combines the CAD system and the DXF blueprint to simplify the steps of automatic inspection by using CAD system.

The main focus of this study is to develop the basic principle and algorithm used for computer aided inspection. The scope of this work includes how to efficiently handle the data structure of the DXF format. The DXF format of AutoCAD is briefly described. Especially, the dimension codes of entities section are noted. We can acquire the information of dimension and tolerance via understanding the information of the DXF file of the blueprint. By using direct parallel slicing of STL triangular meshes, we can obtain the CAD model of points group on 2-D cutting plane surface. Then, dealing with the coordinate transformation by registration, we can match the coordinate systems of the CAD model and the data points correctly. The computer aided quality inspection combines the designed blueprint and 2D CAD model to form an automatic inspection plan according to the items specified on the blueprint. Several examples are presented to demonstrate the entire process and to verify the feasibility of the proposed approach

並列關鍵字

coordinate registration ； STL ； CAD aided inspection ； DXF

參考文獻

2.FC. Tien, CY. Cheng, “Extraction of machined features from two dimensional orthographic drawings”,University of Missouri-Columbia, Master thesis ,1997.

3.JH. Song, Im. Yt, “Expert system for the process sequence design of a ball stud”,Journal of Materials Processing Technology ,21, pp. 72-78,1999 .

4.張瀅, “Research of graphics database management system upon dwg﹑dxf”, China.

5.田方治, “ Using caip for inspection of substrate design”, Department of Industrial Engineering and Management National Taipei University of Technology, 1997.

6.CP. Lim, CH. Menq, “CMM feature accessibility and path generation”, International Journal of Production Research ,32,pp.597-618, 1994 .