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基于自由曲面加工特征的精加工刀具路径生成

发布时间:2024-01-29 19:03
  目前,许多产品的设计都包含自由曲面,尤其是在汽车,航空航天、造船、模具等行业,自由曲面主要用于产品功能和视觉效果的改善。自由曲面表面特征光滑,通常包含凸、凹、鞍形等特征,有时包含这些特征的混合形状,以满足其应用需求。三轴或五轴计算机数控(CNC)机床用于加工自由曲面。旨在减少整体刀具路径长度的方法已成为计算机辅助制造(CAM)领域中的一个巨大研究课题。这种方法通常是固定残余高度约束下生成自由曲面加工刀具路径最短,刀具路径长度信息是预测加工时间的重要因素。本文在前人研究的基础上,研究了不同的自由曲面特征,使用不同的加工刀具轨迹生成策略的效果,对自由曲面加工策略的选择具有一定的指导作用。主要做了一下工作:(1)提出了一种自由曲面特征提取算法。根据曲率,将自由曲面的特征定义为凸,凹和鞍三种类型。边界跟踪方法旨在提取混合特征表面的每个特征边界。获得具有单个曲率特征的表面区域。(2)根据自由曲面的加工特征,采用等参数和等残余高度两种加工方法来分析刀具轨迹的产生。通常,等参数和等残余高度加工方法要求机床用户输入一些刀具路径信息,据此,在加工表面上生成刀具路径。(3)通过编程计算,研究三种类型的自由...

【文章页数】:97 页

【学位级别】:硕士

【文章目录】:
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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