浅谈塑料模具分型面设计

在注射模具的设计中,分型面的设计很关键,其设计的结果将直接影响到模具结构、模具加工难度和模具制造费用。论述了分型面设计中的一些基本原则,并对一些常见的塑件产品,由于分型面的选择不当而造成的缺陷进行了分析研究,为一些典型塑件产品的模具设计提供了一定的理论基础,提高了模具设计效率,减少了塑件产品缺陷。     

Pro／E中“裙边分型面”法分模思路探讨

Pro／E中裙边分型面法对于复杂的塑胶产品的分模是一种较好的设计方法,通过对裙边分型面分模思路的探讨,可以明确裙边分型面法的分模原理,进而明了裙边分析面分模的流程,结合塑胶模具设计的专业知识．可以快速的设计出合理的模具分型面。裙边分型面分模的基本思路就是主分型面（外围分型面）使用裙边分型面快速的创建,破孔分型面则根据模具结构要求可以通过基本做曲面的方法完成内部的分型面。     

CAD APPROACH FOR PLASTIC MOULD PARTING DIRECTIONS OPTIMIZATION

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Feature extraction from freeform molded parts for moldability analysis

In the design of plastic injection molds, the depressions and protrusions (DP) preventing the removal of molded part from mold are referred to as undercuts. This paper describes an approach to recognize DP feature within the curvature region representation based on the curvature properties of entities in B-rep model. The recognized depression features and the concave transitions between protrusion features are potential undercuts which affect the choice of parting directions of the molded part. The possible withdrawal directions of the potential undercuts are derived by geometric reasoning and visibility map computation. This method can recognize isolated and intersecting features with planar, quadric, and freeform surfaces. The identified potential undercuts with their possible withdrawal directions can provide decision support information for mold design such as selecting parting direction, parting lines and surfaces, etc. The case study is presented to verify the feasibility of the developed method.     

Automated Generation of Lifters for Injection Moulds

An algorithm for automated identification of undercuts and the creation of the lifter subassembly in plastic injection mould design is described. The algorithm is suitable for injection mould design in a 3D mode. The input to the software is a 3D part model, parting direction and lines, and a mould-base. The software then generates the lifter subassembly and places it properly in the mould-base. This is accomplished in four steps. First, the so-called virtual core and cavity are generated without considering any undercuts. Undercut faces on the part are then identified and undercut groups are formed. Secondly, the releasing direction of each undercut group is found. Thirdly, for each undercut group, a lifter head based on its releasing direction is created. Fourthly, other standard components of a lifter assembly are retrieved and attached to the corresponding lifter head within the mould-base at the correct location. A case study is presented that illustrates the efficacy of the technique for the automated design of lifters to fulfil a real industrial requirement.     

基于事例推理的模具分型面设计方法研究

在全面分析分型面自动设计方法的基础上，提出了基于事例推理的注塑模分型面设计方法，给出了基于事例推理的分型面设计总体框架。运用特征造型技术进行塑件三维建模，以主形状特征为索引构建了含有分型面信息的塑件事例知识库。采用正向推理策略与相似性求解相结合的方法，实现了模具分型面的自动推理设计，给出了分型面位置设计的推理方法与流程，提高了模具设计的质量和效率。     

多自由曲面产品注塑模具分型线的自动确定

为有效地确定多自由曲面产品模具分型线问题,提出了一种将特征识别技术和有限元方法相结合的模具分型线确定方法。在该方法中,首先,提出了基于图的特征识别方法来对产品中的侧凹特征进行识别,并在识别的基础上对产品模型进行简化;然后,提出了基于有限元的离散方法,对简化的产品模型的所有组成面进行离散,并根据网格面的可视性来判别组成面的可视性;最后,将产品中的所有组成面分成可视面组、不可视面组和退化面组,并通过抽取可视面组或不可视面组的最大边环来确定模具的分型线。研究实践表明,通过该方法可以有效地解决多自由曲面产品模具分型线的确定问题,提高模具设计的效率。     

基于UG NX 6.0 Mold Wizard的侧向抽芯直接分模方法

针对一需侧向抽芯的塑件,在UG NX 6.0中的Mold Wizard模块中,准确设置分型线,合理将分型面进行组合,快捷巧妙生成型芯、型腔及侧抽芯等,从而获得了实际应用的操作方法。使用该分模技术,有利于降低分模难度,提高模具设计精确度,掌握Mold Wizard分模的特点,为模具设计人员提供便利。     

壶体注塑模设计

在注塑模具中分型面的设计将直接影响模具的复杂程度和制造成本,并对产品的质量产生影响。以PRO/MOLD-ESIGN软件包为工具,通过对电热壶体的结构和工艺性分析,较详细地论述了电热壶体模具分型面的设计,并阐述了在PRO/MOLDESIGN上快速生成模具型芯、型腔的方法。     

CCD扫描器外罩模具设计

通过对CCD扫描器的上、下罩零件结构进行分析,着重阐述了该成型模具的设计思路,包括型腔数及型腔的设置,模具分型面的选择,侧抽芯机构及浇注系统设计的要点。通过采用多角度相交的异形分型面、潜伏式浇口和斜顶出式内抽芯等结构,正确选择注射机,可获得近乎完美的外罩零件。该模具结构设计合理、操作简便,既便于加工,又易于保证精度。注射机的顶杆和带内抽芯功能的斜推杆同时作用,在抽芯的同时,可实现塑料件平稳安全的脱模。潜伏式浇口的创新运用,提高了零件生产的自动化程度。     

基于UG MoldWizard软件注塑模分型面设计初探

注塑模具分型面设计是模具设计中的重要部分,首先介绍模具分型面的选择原则,通过典型案例介绍UGMoldWizard四种分型面的创建方法.提出注塑模分型面设计的关键是判斯创建的分型线是否在同一个平面或是曲面内,再采用相应创建曲面的方法创建分型面.目的是为类似注塑件分型面的创建提供参考.     

基于UG的注塑模具设计分模方法

UG的注塑模具设计过程是类似的,但作为模具设计最重要的一个环节分模却是灵活多变的。以风扇叶塑件为例,介绍了分模的基本原理,阐述了基于UG的自动分模与手工分模方法的分模过程,两种方法的灵活运用可大大提高注塑模具设计的效率。     

基于Pro/E的大滑块注射模设计

对盒盖结构工艺性分析之后,使用Pro/E在零件模式下修补破孔,利用裙边曲面创建主分型面,详细论述了从前模和后模等大体积块上分割滑块和镶件等小体积块的过程,从而完成大滑块注射模的分模设计。     

DISCRETIZATION APPROACH USING RAY-TESTING MODEL IN PARTING LINE AND PARTING SURFACE GENERATION

Surface classification, 3D parting line, parting surface generation and demoldability analysis which is helpful to select optimal parting direction and optimal parting line are involved in automatic cavity design based on the ray-testing model. A new ray-testing approach is presented to classify the part surfaces to core/cavity surfaces and undercut surfaces by automatic identifying the visibility of surfaces. A simple, direct and efficient algorithm to identify surface visibility is developed. The algorithm is robust and adapted to rather complicated geometry, so it is valuable in computer-aided mold design systems. To validate the efficiency of the approach, an experimental program is implemented. Case studies show that the approach is practical and valuable in automatic parting line and parting surface generation.     

Automatic feature recognition for plastic injection moulded part design

The design of plastic injection moulded part is a highly iterative process and depends largely on the human expertise including product designers, mould designers, manufacturing engineers, who need to possess thorough and broad specific knowledge and experience. The automatic recognition of features for injection moulded parts is the first prominent stage for any automatic design evaluation system. In this paper, features of plastic product are classified in three hierarchical levels of primitive features, complex features and high-level complex features. The proposed method adopts a hybrid approach, which combines the graph theoretic approach with the logic approach. Methodologies of enhanced multi-attributed adjacency graph (EMAAG) and feature-interaction feature graph (FIFG) for automatic extraction of primitive features and complex features of plastic parts, respectively, are presented. The test example shows that the methodologies developed can recognise various features of injection moulded parts successfully.     

往复式骨架油封模具自动化设计技术研究

针对骨架油封模具设计周期长的问题,通过对往复式骨架油封进行研究,以模具设计为出发点,对模具中关键分型线的确定方法进行了研究,并分析了余胶槽、顶杆和相关壁厚等关键地方的变形规律,建立了数学模型。采用自顶向下的建模方法对模具总体装配及零件进行建模,依据模具设计规则,从油封三维模型的几何特征中提取构成模具型腔的各个零件及其分型线的关键特征,形成封闭的型腔特征曲面,进而利用这些特征曲面切除装配结构中的各个模板零件内侧特征,获得模具型腔结构特征,完成模具详细设计。该设计方法实现了骨架油封模具随油封尺寸自动变形设计,大大提高了设计效率。     

基于离群算法组合曲面特征点提取的研究

为了克服目前组合曲面提取特征点算法中阈值选取困难导致边界特征点误判的缺点,在对组合曲面特性进行分析的基础上,提出了一种基于离群算法的组合曲面特征点提取算法。该算法根据曲面特性定义了曲面域和曲面域深度,在空间统计学基础上引入正态分布的标准单位数和置信系数,采用空间数据挖掘中的离群算法提取组合曲面特征点。通过在某型摩托车零件中的应用,表明了该方法可以有效地避免阈值选取问题,且证明了该算法的有效性和实用性。     

复杂曲面模具加工系统综合刚度场建模与分析*

在加工汽车覆盖件模具复杂曲面时,机床-刀具刚度、刀具位姿变化、模具型面变化都会影响加工系统综合刚度,进而影响模具加工精度。以四轴数控加工中心为例,针对模具曲面特征设置相应采样点,依据多体小变形理论,通过点传递矩阵、雅可比矩阵等完成该采样点的加工系统综合刚度建模,并引入了力椭球。在刀具不同的空间姿态下,通过力椭球分析了机床横梁、刀柄、刀具、模具曲面特征等对加工系统综合刚度性能的影响,揭示了曲面模具加工系统综合刚度的分布规律。最后通过试验证明,该理论模型可以有效地优化复杂型面模具加工工艺,减小模具的加工误差。     

基于事例推理技术的涡轮叶片精铸模分模设计研究与应用

飞机发动机涡轮叶片的内部结构相当复杂,这给叶片模具的分模设计带来了很大的困难。通过对传统手工分模设计过程的分析,并针对分模设计经验依赖性强的特点,指出基于事例推理的分模设计方法的可行性,构建了基于事例推理的涡轮叶片分模设计系统框架,解决了分模设计的分模知识提取、分模事例描述、分模事例检索、分模事例修改等关键问题。最后给出了系统运行实例,表明能够提高设计效率,减少设计难度。     

线切割加工模具表面粗糙度的研究与应用

以模具零件曲面加工为目标,对快走丝线切割加工技术进行了研究.在线切割加工放电间隙、模具零件表面加工粗糙度的理论分析基础上,探讨了影响线切割模具加工的工艺评价指标因素;通过研究加工模具零件表面粗糙度的两个主要构成要素,提出了提高和改善线切割加工模具表面粗糙度的措施,只有综合考虑各方面的影响因素才能获得模具零件加工好的表面...