模具製造之逆向工程技術研究

Reverse Engineering in Die Manufacturing

莊瑞南(Jei-Nan Chuang)

指導教授 ： 李碩仁

元智大學/工程學院/機械工程學系/碩士(1993年)

摘要

在沒有工程設計圖而要去製造工件，這就是所謂逆向工程 (revrse
engineering)。首先必須先對實體工件作數值化 (digitization)，一旦
工件被數值化，這數值化的資料可以輸入 CAD/CAM系統來產生加工所須的
刀具路徑並用來重新產生工件。在台灣，汽車鈑金模具大部分是經由成
品(圖)->基準模->石膏模->保利龍模->翻砂->加工->組立->試模的程序。
這種由現有產品反向推導製造程序及模具設計與製造的技術，便是逆向工
程的一種應用。本文首先探討用接觸式探針配合三次元測定機來掃瞄複合
曲面(compound surfaces)的方法，目的在將不存在任何CAD模型的實體工
件作正確的數值化，並進一步探討將點群數據資料導入 CAD/CAM系統的整
合研究，且利用CAD/CAM系統來作曲面重建及產生數值加工程式的方法探
討。由於使用CAD/CAM系統來作曲面重建，會遭遇系統傳輸介面、掃瞄資
料的重整或簡化及資料太大所影響的計算效率等問題；而專用掃瞄加工軟
體絕大多數為工作站級，其價格昂貴、使用不易。所以我們便規劃並發展
一套在PC級電腦可由掃瞄資料作布林運算並產生數值加工碼的軟體系統，
其目的可用來作3軸銑削功能。系統設計重點含蓋圖形人機介面，三維物
體的觀測，模型的鏡像、比例縮放及公母模反轉，及後處理器設計，我們
並且用兩個實例，一個為汽車鈑金件模型，另一個為鞋模模型來印證本套
系統的功能，來達成產品複製或再生的目的。

關鍵字

複合曲面 ； 逆向工程 ； 輪廓掃瞄 ； 逆向式電腦輔助製造

並列摘要

Manufacturing firms oftentimes wish to reproduce a part
forering drawing does not exist. In such "reverse engineering"
situations, to digitize the existing part as a first step. Once
the part is the data can be used as input to the CAD/CAM system
to generatepath in order to reproduce the part.In Taiwan, the
development ofs die involves the following process: product
design -> master model -> plaster model -> casting -> machining
-> assembly and finally The process of recreating manufacturing
process and dieuring from existing parts is called reverse
engineering. This thesis describes schemes for scanning
compound surfacesMeasuring Machine(CMM) equipped with a touch
probe. The main purpose is to digitize the presumed to have no
existing computer aided design(CAD) model.Thering process by
the integration of CMM and commerical CAD/CAM package was
alsohere are CAD/CAM packages such as Pro/Engineer and SmartCAM
can acceptdata. And surface model can be rebuilt inside the CAD/
CAM systems toC maching codes. However, one may encounter
difficulties such as datadata format and reduction of scanning
data and massive data point when using currents to process
digitized point data. Some special package that havecapability
were workstattion-based, expansive and user hostile. Therefore,
ae-type CAM system was developed. This system which is based on
discreate point and boolean operation can generate NC codes
without building surface model. It was fast and can handle
massive digitized points. This system includes on-line
graphics, data scaling, translationale and female conversion,
and post processor to generate NC codes for various.

並列關鍵字

Compounded Surfaces ； Reverse Engineering ； Contour e-type CAM