方形切削工件中多組特徵組之製程分析與評估

Analysis and Evaluation of Process Planning for Prismatic Machined Parts with Multiple sets of Features

林傳城(Chwan-Cherng Lin)

指導教授 ： 鄭元杰

元智大學/工程學院/工業工程與管理學系/碩士(1995年)

摘要

本研究提出一個在方形切削工件中多組特徵組分析與評估之方法，
其主要之目的在於評估多組的特徵組，進而找出最佳或是合適的特徵組以
產生製程。在特徵為基之設計中，可能存在有多組同樣有效的特徵組，可
表示同一工件之外型。本研究中首先處理在經由體積分解（Volume
Decomposition）後之特徵總切去體積，可形成許多基本方形切去體積，
再利用此基本方形切去體積的幾何資料與其間之鄰接關係，以有系統之連
接與組合之方法，產生多組不同之特徵組，並進行分析與評估。 在連
結成多組特徵組方面，其方法是利用體積分解之後所得體積鄰接關係與幾
何資料，將相同高度之方塊先連結成較大之方塊體積，再以此方塊往三軸
方向連結更大之方塊，最後形成多組同樣有效之特徵組。由於此多組特徵
組代表多組可能即可行之製造程序，本研究中從製程規畫之觀點，分析及
評估多組特徵組之可行性或何組較佳。首先從刀具路徑的觀點分析規畫各
種特徵方塊之刀具路徑，並利用其計算刀具在每一特徵內切削路徑（
Cutting Tool Path），與特徵間空切削路徑（Non-Cutting Tool Path）
，將此二者加總以得到一特徵組之總切削路徑之長短。比較其各組特徵組
刀具總切削路徑之長短為評估因素之一。另外，刀具於切削與空切削之行
經速率不一，故計算每組特徵組之總切削時間並比較，為評估因素之二。
接著從夾具夾持點的觀點以4-2-1之定位原則規畫夾具設計（Fixture
Design），以夾持在切削特徵組所產生過渡工件，並比較夾具夾持過渡工
件所做之改變次數此其評估因之三。並且綜合以上評比之因素以便找出較
佳之特徵組，以利下游之電腦輔助製造來運用。 本研究結果主要貢獻
能於多組特徵組中，評估出一組較佳特徵組提供製程上之運用，並使電腦
輔助設計與電腦輔助製造做更佳之整合。關鍵詞：電腦輔助設計、電腦輔
助製造、刀具路徑、夾具設計。

關鍵字

電腦輔助設計 ； 電腦輔助製造 ； 刀具路徑 ； 夾具設計

並列摘要

In this thesis ,we develop a method to analyze and evaluate
the multiple sets of features in the prismatic machined parts.
In feature-based design, alternative sets of features can exist
to represent the same part model. The main goal of this research
is to analyze and evaluate these multiple sets of features in
order to find a better set or the best set suitable for
manufacturing process planning. In this research ,firstly, a
volume decomposition method is used to build basic machined
components from feature volumes. Then, a systematic method is
developed to reconstruct the basic machined components to
generate multiple sets of features. These multiple sets of
features are then analyzed and evaluated from process planing
point of view. There are two stages in this research. In the
first stage, the multiple sets of features are generated by
connecting the BMC with the same level and then connecting the
blocks along three possible directions to build 3D features and
generate the multiple sets of features. In the second stage ,the
multiple sets of features are analyzed and evaluated from
process planning of view by considering two factors, tool paths
and fixturing design. Machining a part by using different
feature sets requires different sets of tool paths that may
differ in length of paths. A method for cutting tool path and
non-cutting tool path planning and calculation of these
prismatic features are developed. The multiple sets of features
are then analyzed and evaluated by calculating the length of
different tool paths. The total cutting time of each of these
multiple sets of features is also evaluated. A method for
feature-based fixturing design by using 4-2-1 location principle
is developed to evaluated the fixturing requirement for
machining the multiple sets of features . Since machining a part
by using different set of features may produce different
intermediate shapes during machining, there may require
different fixturing methods for different intermediate shapes in
machining different sets of features. The multiple sets of
features are then analyzed and evaluated based on the times of
the fixturing changeovers resulted from the different shape of
the intermediate workpieces. Finally, all the above factors are
combined to conclude a better set or a best set of features.
The contribution of this research is to find a better set of
features from the multiple sets of features. Such that a better
way to integrate CAD and CAM can be found.Keywords:CAD, CAM,
tool path, fixture design.

並列關鍵字

CAD ； CAM ； Tool Path ； Fixture Design