目前,許多產(chǎn)品的設(shè)計(jì)都包含自由曲面,尤其是在汽車,航空航天、造船、模具等行業(yè),自由曲面主要用于產(chǎn)品功能和視覺(jué)效果的改善。自由曲面表面特征光滑,通常包含凸、凹、鞍形等特征,有時(shí)包含這些特征的混合形狀,以滿足其應(yīng)用需求。三軸或五軸計(jì)算機(jī)數(shù)控(CNC)機(jī)床用于加工自由曲面。旨在減少整體刀具路徑長(zhǎng)度的方法已成為計(jì)算機(jī)輔助制造(CAM)領(lǐng)域中的一個(gè)巨大研究課題。這種方法通常是固定殘余高度約束下生成自由曲面加工刀具路徑最短,刀具路徑長(zhǎng)度信息是預(yù)測(cè)加工時(shí)間的重要因素。本文在前人研究的基礎(chǔ)上,研究了不同的自由曲面特征,使用不同的加工刀具軌跡生成策略的效果,對(duì)自由曲面加工策略的選擇具有一定的指導(dǎo)作用。主要做了一下工作:(1)提出了一種自由曲面特征提取算法。根據(jù)曲率,將自由曲面的特征定義為凸,凹和鞍三種類型。邊界跟蹤方法旨在提取混合特征表面的每個(gè)特征邊界。獲得具有單個(gè)曲率特征的表面區(qū)域。(2)根據(jù)自由曲面的加工特征,采用等參數(shù)和等殘余高度兩種加工方法來(lái)分析刀具軌跡的產(chǎn)生。通常,等參數(shù)和等殘余高度加工方法要求機(jī)床用戶輸入一些刀具路徑信息,據(jù)此,在加工表面上生成刀具路徑。(3)通過(guò)編程計(jì)算,研究三種類型的自由...

【文章頁(yè)數(shù)】：97 頁(yè)

【學(xué)位級(jí)別】：碩士

【文章目錄】：
ABSTRACT
摘要
CHAPTER1.INTRODUCTION
    1.1.Research Background and Significance
    1.2.Research status for related works
        1.2.1.Extraction of features
        1.2.2.Tool Path Generation
    1.3.Research Innovations and Main Objectives
    1.4.Organization Structure and Arrangement
CHAPTER2.FREE-FORM SURFACE FEATURE EXTRACTION
    2.1.Basic Principles of Free-form Surface Feature Extraction
    2.2.Overview of Free-form Surface Feature Extraction
    2.3.Parametric Representation of Surfaces
    2.4.Curvature of a Surface:Gaussian and Mean Curvature
    2.5.Implementation of Freeform Surface Feature Extraction
        2.5.1.Points shape type classification
        2.5.2.The Definition of Boundary Points of Freeform surfaces
        2.5.3.Boundary tracing method extracts processing feature boundaries
        2.5.4.B-Spline Representation and Segmentation of Feature Boundary
    2.6.Results and discussion
CHAPTER3.TOOL PATH GENERATION
    3.1.Introduction
    3.2.3-Axis Machining
        3.2.1.Basic Principles of3-Axis Machining
    3.3.5-Axis Machining
        3.3.1.Basic Principles of5-Axis Machining
    3.4.Machining Tool Path Generation
        3.4.1.Basic Principles of Tool path generation
    3.5.Machining Methods
        3.5.1.Overview of Iso-scallop machining Concept
        3.5.2.Overview of Iso-parametric machining Concept
        3.5.3.Basic Principles of Iso-scallop machining Method
        3.5.4.Basic Principles of Iso-parametric machining Method
    3.6.Tool Path Parameters
    3.7.Step over calculation
    3.8.Tool Path Distribution Strategies
        3.8.1.Basic Principles of Tool Path Distribution Strategies
        3.8.2.Overview of Tool Path Distribution Strategies
    3.9.Brief Summary
CHAPTER4.MATERIALS AND METHODS FOR THE TOOL PATH’S LENGTH COMPUTATION
    4.1.Introduction
    4.2.Freeform Surface Generation
    4.3.Tool Path Generation Method
    4.4.Tool Path Distribution
    4.5.Computation of Tool path’s Length
    4.6.Summary
CHAPTER5.RESULTS ANALYSIS AND DISCUSSION
    5.1.Results of the of Tool path’s Length Computation
        5.1.1.First experiment
        5.1.2.Second Experiment
        5.1.3.Third Experiment
    5.2.Summary
CONCLUSIONS AND FUTURE WORK
REFERENCES
ACKNOWLEDGEMENT



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