注塑模流道系统集成设计技术研究

通过总结注塑模流道系统的设计知识,结合基于特征的设计、专家系统技术和ＣＡＥ分析工具,对流道系统进行完整全面的设计,利用专家系统进行流道和浇口的初始设计,采用ＣＡＥ工具Ｃ－ＭＯＬＤ和评价目标函数,进行流道和浇口的优化设计,并总结流道和浇 形状特征,最终建立流道系统的特征和实体模型,这一方法已较好地应用于构造新一代注塑模设计制造系统中。     

神经网络与专家系统结合的DSS模型智能构造

模型智能构造是目前IDSS发展的一个趋势.针对DSS模型构造中存在的问题,提出了一种神经网络与专家系统结合的DSS模型智能构造方案及其系统结构.在对文字描述和数据描述分离的基础上,应用专家系统实现模型类型的选择,应用神经网络实现模型结构的构造.以ARMA模型智能构造为例,说明了方法的可行性和有效性.     

基于神经网络集成的专家系统模型

提出一种基于神经网络集成的专家系统模型,并给出神经网络集成的构造算法.在该模型中神经网络集成作为专家系统的一个内嵌模块,用于专家系统的知识获取,克服了传统专家系统在知识获取中的＂瓶颈＂问题.并将该模型用于图书剔旧系统中,初步建成基于神经网络集成的图书剔旧专家系统原型.     

基于STEP的注塑模应用活动模型研究

本文分析了建模技术的发展，指出基于ＳＴＥＰ的建模策略可以满足集成制造系统对产品模型的要求，并用ＩＤＥＦ０方法对注塑模系统进行了分析，建立了注塑模产品活动模型，并指出基于此活动模型为研究范围的注塑模产品模型可以满足集成化的注塑模系统的要求。     

基于模糊神经网络的导弹故障诊断专家系统

为了实现对导弹测发控系统的故障诊断,研究了模糊神经网络理论与算法,以及和专家系统的结合方式;综合神经网络、专家系统和模糊逻辑的各自优点和特点,提出了构建基于模糊神经网络的故障诊断专家系统的基本原则,并给出了一种构建方法;通过将传统的专家系统技术与模糊神经网络技术相融合,文中构造了某型导弹测发控系统智能故障诊断系统,验证了方案的可行性,为类似系统的进一步实现进行了有益的探索。     

基于神经网络的故障诊断专家系统研究

针对传统专家系统和神经网络的各自特点,将两者有机结合,构造了一种基于神经网络的混合型故障诊断专家系统。提出了神经网络子模块NNM的概念并分析了NNM的具体实现方法。应用该故障诊断模型对某内燃机组供油系统故障进行了模拟验证,试验结果表明神经网络与专家系统结合是一种有效的诊断方法。     

基于神经网络的注塑模KBE系统开发

针对现有注塑模具设计CAD系统存在的缺点，提出基于神经网络的注塑模KBE系统开发思想。阐述了模具设计的特点、KBE的内涵和特点以及神经网络的原理和在模具设计KBE上的应用，设计了基于神经网络的摩托车塑件模具设计KBE的基本系统框架，并分配了模具设计KBE系统中神经网络算法的榆入、输出以及隐层各神经元，为注塑模具设计KBE提供了系统构造基础研究。     

自动装弹机电控系统故障诊断专家系统

基于神经网络的自动装弹机电控系统故障诊断专家系统不但可以对自动装弹机电控系统进行故障检测,而且可以对程序控制盒进行试验,以考核程控盒的技术状况;该系统从自动装弹机的电气控制系统出发,以人机交互的方式,直观地帮助用户进行系统的故障检测和故障诊断,并给出了软件的部分界面以及诊断结果,验证了系统的可行性;根据专家系统与神经网络的结合方式,建立了基于神经网络的故障诊断专家系统(NNES)的模型及系统各组成部分的结构和设计方法。     

人工神经网络专家系统在门窗选型中的应用

本文提出了一个将神经网络专家系统的设计思想引入门窗选型过程的应用模型,从而提高了门窗选型的合理性,也充分发挥了神经网络及专家系统的各自优点。文中主要介绍了基于神经网络专家系统的门窗选型模型的结构和推导过程,此模型在实际应用中确实取得了令人满意的效果。     

遗传神经网络技术在专家系统中的应用

讨论了神经网络在专家系统中的应用,提出了神经网络专家系统的设计方法,给出了系统的结构,论述了系统实现中的一些技术问题。分析了遗传算法及BP神经网络的理论基础,讨论了遗传算法、神经网络与专家系统的结合方式。在专家系统中应用遗传神经网络技术,具有独创性,理论和实践上都具有重要意义,进一步丰富了选矿专家系统的研究方法。建立相应的遗传神经网络模型,论述了选矿数据预处理的方法、BP神经网络的设计,提出了相关参数的经验选取办法。通过实例验证,模型的预测精度可以达到90％以上。     

一种基于自动特征识别确定模具脱模方向的方法

判定脱模方向是实现模具自动设计的第一步,也是评估塑件或浇注件能否模具成型的重要因素,文中以基于广义痕迹的自动特征识别方法来识别塑件模型中的所有特征。首先,通过确定每类塑件特征的候选和可行脱模方向,针对每个识别出的特征,自动产生该特候选的脱模方向,然后把所有具有机或完全相反的候选的脱模方向组成一组,并对每组方向,进行选定的模具因子计算,最终胡定优选的脱模方向。实例测试表明,本文提出的方法具有很高的效     

A visual mold with variotherm system for weld line study in micro injection molding

In order to study the weld line developing process and its influence on mechanical properties in micro injection molding, a visual mold with variotherm system mold was designed and fabricated. In this mold, a visualization design and a rapid heating/cooling system were integrated, and specimens with different cross section shape and micro dimensions could be molded for weld line study. The building process for the visual and variotherm mold was presented and the experiments were executed. The specimens for weld line study of micro injection molding were produced applying different processing parameters. A problem of flash in molded specimens needs to be solved.     

The application of surface demoldability and moldability to side-core design in die and mold CAD

In casting, molding and forming processes, the surface geometries of the fabricated products are formed/molded by different functional components of tooling. In plastic injection molding, they are molded by core, cavity or side-cores. In die and mold CAD, how to identify the product surfaces formed/molded by the corresponding tool components for a given product CAD model is critical, as it affects the determination of parting directions, parting lines and parting surfaces, the generation of core and cavity blocks, and finally the design of side-cores and their actuating mechanisms. In this paper, the concepts of surface visibility, demoldability, and moldability are first presented and formulated. The surfaces formed/molded by core, cavity and side-cores are then defined based on the plastic injection molding process. The methodology to identifying and classifying them is further developed. By employing the proposed notions of the demoldability map of surfaces and undercut features, the most preferred demolding direction, the grouping of undercut features, and how to conduct the side-core design is articulated succinctly, and the detailed procedures and processes are presented. Through an industrial case study, the developed methodology for side-core design is systematically presented and the feasibility of the developed approaches is verified.     

Improving FEM crash simulation accuracy through local thickness estimation based on CAD data

In this paper, we present a method for estimating local thickness distribution in finite element models, applied to injection molded and cast engineering parts. This method features considerable improved performance compared to two previously proposed approaches, and has been validated against thickness measured by different human operators. We also demonstrate that the use of this method for assigning a distribution of local thickness in FEM crash simulations results in a much more accurate prediction of the real part performance, thus increasing the benefits of computer simulations in engineering design by enabling zero-prototyping and thus reducing product development costs. The simulation results have been compared to experimental tests, evidencing the advantage of the proposed method. Thus, the proposed approach to consider local thickness distribution in FEM crash simulations has high potential on the product development process of complex and highly demanding injection molded and cast parts and is currently being used by Ford Motor Company.     

Design and fabrication of a micro Alvarez lens array with a variable focal length

A 5 × 5 micro Alvarez lens array mold was fabricated using a 5-axis ultraprecision diamond machine and an Alvarez lens array was manufactured by injection molding process. Unlike conventional processes for asymmetrical element fabrication such as small tool grinding, this research demonstrates slow tool servo broaching process that allows the entire Alvarez lens array to be accurately machined on a metal mold in a single operation. To further reduce manufacturing cost, injection molding was used to fabricate the Alvarez lens arrays. The mold and molded lenses were both measured using an optical profiler. All measured profiles showed a good agreement with design and surface roughness also indicated an optical surface finish. The functionality of the molded polymeric lens arrays was achieved when the focal lengths were varied by laterally translating the molded Alvarez lens array pair. This research is a demonstration of the capability of fabricating complex optics using the same approach.     

A knowledge-based process planning system for injection mold

The goal of this study is to develop a knowledge-based process planning system interfaced with design for injection mold. Mold parts are interactively designed by using feature-based design approach, and then a part feature database is created through a data conversion module. Attribute information of the database is used as an input for the expert process design module and the standard time estimation module of the knowledge-based process planning system developed in this study. In this developed system, decision making of process design is performed by rules which were acquired from experienced process planners through interviews, and machining operation time is estimated by using empirical formulas derived from the actual shop floor data. A case example of split cavity plate is used to demonstrate the system performance.     

Simulation of the filling process in molding components with micro channels

In micro molding of components with micro features, the ability for the polymer melt to flow into the micro channels is a crucial factor for successful molding. In this case, the molded volume is about the same as the conventional molding. The penetration distance into the microstructure depends on the flow rate and the cooling rate of the micro features, which is function of the geometric dimensions. In this study, a simplified model was established to estimate the injection distance into the micro channels of a mold insert. The effect of the mold temperature, injection rate, and micro channel dimension on the filling distance was investigated based on the model. The filling distance increases dramatically with respect to the increase of the channel width. In molding of components with micro features as those analyzed in this study, decrease of the part thickness could enhance the filling in the micro features.The authors would like to thank for the financial support from National Science Council in Republic of China under the contract number of NSC 91-2212-E006-131.     

Numerical Simulation of Injection Molding Cooling Process Based on 3D Surface Model

The design of the cooling system of injection molds directly affects both productivity and the quality of the final part. Using the cooling process CAE system to instruct the mold design, the efficiency and quality of design can be improved greatly. At the same time, it is helpful to confirm the cooling system structure and optimize the process conditions. In this paper, the 3D surface model of mold cavity is used to replace the middle-plane model in the simulation by Boundary Element Metho…     

The application of surface visibility and moldability to parting line generation

In molding, casting or forging processes, part surfaces are formed by the core, cavity and local tools in molding/casting or by the upper and lower dies and local tools in forging. In computer-aided design of dies and molds, automatic identification of surfaces molded/formed by these different tooling components is critical since the generation of parting lines depends on these surfaces, which would further influence the determination of parting surfaces, the creation of core and cavity blocks and the entire mold structure. In this paper, the surface partability and visibility are first proposed and its moldability is next presented. Considering the molding process as an instance, the concepts of core-, cavity- and the local tool-molded surfaces are defined. A methodology based on surface visibility and moldability to determine the potentially and actually moldable surfaces of these groups is developed. Since the generation of parting lines is a crucial preliminary design step in mold/die design life cycle, a new approach to determining the parting lines based on the proposed methodology is presented. A case study is used to test the methodology and approach, and to validate the efficiency in parting line generation of molded parts.     

基于CAD的注塑模具设计与仿真研究

研究了基于CAD技术的注塑模具设计流程,并对模具的工艺参数进行了分析和优化,具体采用CAD注塑模集成系统实现。完成了最优工艺参数方案的确定,通过UG的CAE分析模块的应用并以模拟结果为依据完成了对注塑件应力应变分布情况的分析,应力最大值及位置通过实验对比完成确定,为模具结构的优化方案提供参考。最佳注塑制品工艺参数通过分析相关工艺参数获取,并以音箱零件为例,对注塑模具型腔设计方法进行了探讨。