An intelligent hybrid system for initial process parameter setting of injection moulding

Currently, determination of the initial process parameter settings for injection moulding is mainly performed by moulding personnel, and the effectiveness of the parameter setting is largely dependent on the experience of these personnel. In this paper, an intelligent hybrid system, called HSIM, is described, which is used to determine a set of initial process parameters for injection moulding based on the artificial intelligence (AI) techniques, case-based reasoning (CBR), and hybrid neural network (NN) and genetic algorithm (GA). HSIM can determine a set of initial process parameters for injection moulding quickly, without relying on expert moulding personnel, from which moulded parts free from major moulding defects can be produced.     

药筒精密成形工艺数字化设计系统

介绍了药筒工艺数字化设计系统的特点、设计流程和各功能模块的主要功能。该系统在药筒成形工艺和模具设计过程中融合了基于规则的推理与基于实例的推理,可智能完成工艺参数计算,半制品与模具参数化建模,同时为设计者提供有效的精密成形工艺设计知识和经验帮助,大幅提高了该类零件成形工艺和模具设计效率。     

A hybrid case-based reasoning CAD system for injection mould design

Injection mould design generally lies on the critical path of a new product development. The design efficiency will have significant impact on the overall lead time of a new product. This paper presents a prototype injection mould-design system using a hybrid case-based reasoning (HCBR) approach. Case-based reasoning (CBR) is a solving paradigm that uses previous episodes on solving problems similar to the problem at hand (the new problem) as the basis for solving the new problem. In this hybrid system, CBR is incorporated with generalized design knowledge, and provides a flexible and comprehensive model of design. The knowledge base of the system would be accessed by mould designers through interactive programs so that their own intelligence and experience could also be incorporated with the total mould design. The approach provides a workable model of mould design system with CBR and knowledge-based expert system intelligent support, which could suggest good and proven design solutions to new design problems quickly, avoiding the time necessary to create those designs from scratch, for the plastic products manufacturing industry.     

Online design reuse tool for the support of the generation,embodiment and detailed design of products

Design reuse is becoming a widely accepted strategy to meet the increasingly fierce competition and highly diversified customer needs in product development. In this research, an integrated and systematic framework to computerize the design reuse process was formulated and a prototype online design reuse system was implemented. This system embodies the evolutionary process of design reuse and supports design reuse from the original requirements through the concept and embodiment stage to achieve a final detailed design. The prototype system retrieves products using multi-indices and a stepwise winnowing method. The advanced-search module of the system solves a design problem using two intelligent search methods to retrieve reusable products. Finally, the system can adapt these retrieved products to generate a new design. The design reuse framework is based on related design methodologies such as function taxonomy, product family, etc. Genetic algorithms and case-based reasoning are adopted in this system to achieve an intelligent search. The variant design method is used in detailed design reuse.     

Associativity modelling of a mould assembly for expandable polystyrene foam

The design and fabrication of a mould for expandable polystyrene (EPS) buffers involves an approach which is radically different from that associated with conventional plastic injection moulding. This is because the EPS mould design encompasses both the classical tooling specifications and considerations of the actual moulding process itself. This paper discusses the notion of associativity modelling in the CAD design of a mould assembly for the manufacture of EPS buffers. This modelling paradigm aims to integrate 5 mould design factors with 25 process (moulding) parameters. Through a better understanding of the interactions between design factors and process parameters, and among the process parameters themselves, a harmonious decision table can be derived which compromises the competing demands of factors and parameters. Because of the visibility of the interactions among parameters, the notion of associativity modelling offers the designer a better insight into mould assembly design, leading to practical mould design solutions that harmonize the functions of the different sub-assemblies.     

RTM成型复合材料T型接头工艺参数优化与力学性能实验研究

对树脂传递模塑(RTM)成型的复合材料T型接头进行了工艺参数优化、制备及力学性能实验研究。应用流动模拟软件,对RTM成型的复合材料T型接头进行了基体流动数值模拟,确定模具最佳注射方式和出胶口位置,并优化了影响树脂充模时间的工艺参数,显著提高了RTM接头的工艺性能。根据优化工艺参数结果,制备了RTM成型的复合材料T型接头试样,并进行了拉伸和压缩试验,分析了其破坏机制。根据拉伸和压缩试验现象和结果,发现RTM成型的复合材料T型接头拉伸破坏模式主要为富树脂三角区的树脂与纤维布界面分层,其拉伸破坏主要取决于树脂基体抗剥离分层的拉伸强度;压缩破坏模式为底板中央部位的弯曲分层与折断,其压缩破坏由接头底板中的纤维布抗拉强度决定;T型接头的压缩破坏强度高于拉伸破坏强度。     

Improvement of mechanical properties of recycled plastic blends via optimizing processing parameters using the Taguchi method and principal component analysis

In this paper, the Taguchi method and principal component analysis (PCA) are used to improve the mechanical properties of recycled polypropylene (PP) blends in injection moulding procedure, with detailed assessments performed on each method and comparison was made based on results of both the methods. The experimental design was carried out by adopting a L9-3⁴ Taguchi orthodoxy array (OA), which has four controllable factors (i.e., melt temperature, mould temperature, injection speed and packing pressure) at three levels. Injection moulded specimens made from different compositions of virgin-recycled PP were tested to determine the optimal conditions for the injection moulding procedure. The effects of the processing parameters and the proportion of recycled plastic in composites on the mechanical properties were investigated, the optimal conditions for desired properties were obtained and then verified. The appropriate blending ratio of virgin and recycled plastic was evaluated. The results reveal that deteriorations in the mechanical properties of products produced from recycled plastic can be improved by optimizing the processing parameters during the injection moulding procedure.     

An evolutionary approach for cooling system optimization in plastic injection moulding

The cooling process is of great importance in plastic injection moulding as it has a direct impact on both productivity and product quality. Cooling process optimization is a sophisticated task which includes not only the design of cooling channels but also the selection of process parameters. Most existing optimization systems focus on either cooling channel design or process parameter selection but not both. This paper explores an approach to optimize both cooling channel design and process condition selection simultaneously through an evolutionary algorithm. The prototype system proposed in this paper is an integration of the genetic algorithm and CAE (Computer-Aided Engineering) technology. The aim is to launch a computerized system that can guide the optimization of the cooling process in plastic injection moulding. The objective is to achieve the most uniform cavity surface temperature to assure product quality.     

多约束下的载人潜器舱内计算机辅助工效设计系统研究

为了能使载人潜器舱内工效设计人员加深对多约束条件下舱内人员的生理、心理和环境约束条件的理解,有效地辅助设计方案的智能生成与优化.提出了基于虚拟人体模型参数作为布局设计解空间的参数获取方法、基于遗传算法的舱内人-机界面布局设计方案计算智能求解方法、基于知识推理的舱内色彩工效设计方案获取方法和基于粒子群算法的载人舱工效设计方案智能优化方法,以此为基础,应用UG二次开发和数据库技术,开发了载人潜器舱内人机工效设计计算机辅助系统.通过设计实例的人机工效布局和色彩设计与方案优化验证了该系统的可行性.     

基于实例推理的镀膜机快速设计研究

目的研究大规模定制模式下镀膜机的快速设计方法。方法阐述了基于实例推理技术的基本原理和关键技术,将基于实例推理的快速设计技术应用到镀膜机的设计过程中;研究了镀膜机的实例表示、检索和修正的具体实现方法,即采用数据库表的实例表示方法构建了镀膜机的实例库,运用最相邻策略法进行镀膜机实例的检索,采用基于框架的方案变换方法对检索的最相似实例进行修正。结果以Pro Engineer 5.0为开发平台,开发了基于实例推理的镀膜机快速设计系统,实现了资源的整合和重复利用。通过测试,该系统使设计效率提高了30%。结论将基于实例推理的快速设计技术引入到镀膜机的设计中,能够提高产品的设计效率和缩短产品的开发周期,从而解决客户个性化需求与大批量生产之间的矛盾,提高企业的市场竞争力。     

纵向超声波辅助微注塑方法

微注塑过程中,聚合物熔体在微小腔体中流动时充模阻力比常规注塑大,这影响了熔体填充效果,同时热量损失的不均衡性和不确定性容易导致注塑精度不高．提出了纵向超声波辅助微注塑方法,并对超声波振动对聚合物熔体的作用机理进行了探讨,分析了超声换能器结构对应力、振幅和响应频率的影响．基于对微注塑过程的模拟结果,开发了纵向超声波辅助微注塑装置．通过在微注塑过程中纵向超声波对熔体的能量作用降低熔体黏度,改善了熔体流动和充填性能．为了验证超声波辅助微注塑的效果,进行了菲涅尔透镜实际注塑实验．实验结果表明,相同的注塑工艺条件下,超声辅助微注塑过程中聚合物熔体的充填性能提高了6．91％．     

中开口钢包装桶模具结构研究及优化设计

目的 针对中开口钢包装桶生产工艺流程长、 模具套数多及占用压力机较多的问题, 对模具结构进行研究并提出优化设计方案。方法 分析生产工艺要求, 应用复合模具技术, 通过结构研究、 材料选择和优化设计方案, 计算各套模具的冲压力, 并确定压力机型号。结果 结构设计可靠、 制造方案优化的复合模具能满足生产工艺要求, 实现了合并工序的目的。结论 通过模具结构研究及优化设计、 改造生产流程、 应用复合模具合并工序, 可减少压力机台数, 提高了钢桶生产效率及经济效益。     

The development of a dielectric system for the on-line cure monitoring of the resin transfer moulding process

The aerospace industry has identified the need for an on-line cure monitoring system for the resin transfer moulding (RTM) process which can determine the through-thickness cure state of a composite, without affecting the integrity of the finished component. Several techniques have been extensively investigated but dielectric analysis (DEA) appears to offer the greatest potential. The parallel plate sensor configuration is appropriate for through-thickness measurements. Using a laboratory dielectric instrument, dielectric properties in fibre (conductive and non-conductive) reinforced composite samples have been measured during a simulated RTM cure cycle. Particular parameters derived from dielectric measurements have been shown to be useful in terms of monitoring and optimising the RTM cure cycle. These parameters can be used to identify the key stages in the curing process and to estimate the values of the resin properties at these stages. Correlation of key dielectric events with other thermal data has been shown. Sensors currently are being developed with a view to incorporation into the RTM mould. The ultimate aim of this work is the development of an on-line cure monitoring system for the RTM process in collaboration with Bombardier Shorts.     

采用实例推理的寄生式通用零部件设计系统的研究

提出了一种运用实例推理在SolidWorks 2005环境下开发通用零部件设计系统的方法.通用零部件设计系统是基于SolidWorks 2005最底层API函数,采用寄生式软件开发的方法,利用微软的 Microsoft Visual C 6.0作为开发语言,以提高企业产品开发生命周期的服务系统.阐述了通用零部件设计系统的体系结构和主要功能模块;给出了各模块的实现流程;说明了系统实现的关键技术;用设计实例进行了验证.     

Modelling of Mould Filling and Solidification of Castings

An experimental casting for validation has been designed. The casting is composed of two 50×600×2.5 (width×length×thick) thin-wall pieces. One downsprue is located in the middle. A pouring cup with a stopper is used. This design allows to using two different types of moulds simultaneously. An Al-10%Si alloy has been poured at different temperatures. Two effects have been studied: one is the pouring temperature and the other is the moulding method (namely by machine or manually). The filling length is proportional to the pouring temperature. The influence of different moulding methods on mould filling is more complicated. The filling length in the manual-made mould is 1.5 times as long as the one in the machine-made mould due to the different thermal conductivities. Vents have little influence. A finite volume based computer code which can simulate fluid flow during mould filling coupled with heat transfer as well as solidification has been developed in WTCM Foundry Center.. The code can predict cold shut during mould filling and shrinkage defects during solidification. The simulated results are in good agreement with the experiments.In the second part of the paper, an example is given which illustrates how to use computer simulation to aid designing the casting system. The final computational result is compared with the industrial casting. The process of designing castings by using simulation is completely different from the traditional way. The computer aided casting design offers the possibility to obtain a sound casting from the first time.     

Fuzzy regression approach to process modelling and optimization of epoxy dispensing

Epoxy dispensing is one of the popular processes to perform microchip encapsulation for chip-on-board (COB) packages. However, determination of proper process parameters setting for optimal quality of the encapsulation is difficult due to the complex behaviour of the encapsulant during dispensing and the uncertainties caused by fuzziness of epoxy dispensing systems. In conventional regression models, deviations between the observed values and the estimated values are supposed to be in probability distribution. However, when data is irregular, the obtained regression model has an unnaturally wide possibility range. In fact, these deviations in some processes such as epoxy dispensing can be regarded as system fuzziness that can be dealt with properly using fuzzy regression method. In this paper, a fuzzy regression approach with fuzzy intervals to process modelling of epoxy dispensing for microchip encapsulation is described. Two fuzzy regression models relating three process parameters and two quality characteristics respectively for epoxy dispensing were developed. They were then introduced to formulate a fuzzy multi-objective optimization problem. A fuzzy linear programming technique was employed to formulate the optimization model. By solving the model, an optimal setting of process parameters can be obtained. Validation experiments were conducted to evaluate the effectiveness of the proposed approach to process modelling and optimization of epoxy dispensing for microchip encapsulation.     

基于GSM的智能家居安防系统设计

为了更加方便人们了解并控制家中的电器,我们设计了一套基于GSM模块的智能家居安防系统,实现主人通过给GSM模块发送短信息指令以控制外围设备的目的,包括控制指电灯、空调、热水器等多种功能。它的成本价并不高昂,适合于普通大众使用,有着广阔的市场前景。 其中GSM模块用于接受管理员的短信息,并传送到单片机控制系统。单片机控制系统基于AT89S52单片机,处理来自GSM模块的信息,并根据预先设定的程序和短信命令来控制无线发送模块,MSP430F149单片机通过无线接收模块接收无线命令并控制外围电器。独有的火灾报警系统,可以在家中出现火灾立刻通过短信向主人报告。     

基于案例推理的产品个性化定制方法

目的 针对产品个性化定制过程中用户需求与产品模块匹配度低的问题,提出一种基于案例推理的产品个性化定制方法。方法 首先,构建某类产品案例库和用户需求信息库,并经过对产品案例的模块化分解,构建模块化案例库。当用户在个性化定制系统输入需求信息时,企业利用质量功能展开,建立用户需求项与产品模块属性之间的映射关系,确定用户需求权重和各产品模块的属性及其权重。然后,运用相似度计算、检索,匹配出符合用户需求的产品模块。将产品模块按相似度值进行排序,相似度值较高的模块作为备选模块,使用户可以通过个性化定制系统进行产品模块的配置。最终,系统生成产品个性化定制方案。结论 以民族风桌布为例,阐述了产品个性化定制的具体方法与流程,并验证了该方法的有效性,为企业提供了一种高效的产品个性化定制方法。     

压电智能连续体结构/控制一体化广义拓扑优化

对于以往较少涉及到的同时考虑结构拓扑、作动器位置与数目和控制器参数等多种优化设计变量参与的压电智能板结构的一体化优化设计问题,研究了结构/控制一体化广义拓扑优化设计的方法。提出采用基于耦合模态空间的二次型最优控制系统设计与基于遗传算法和数学形态学处理的策略进行一体化拓扑优化设计实现。数值算例的结果表明,所提方法合理、有效,能够得到清晰的结构拓扑和良好的可控性。     

Effect of process parameters and optimization of CO2 laser cutting of ultra high-performance polyethylene

The aim of this work is to relate the cutting edge quality parameters (responses) namely: upper kerf, lower kerf, ratio of the upper kerf to lower kerf and cut edge roughness to the process parameters considered in this research and to find out the optimal cutting conditions. The process factors implemented in this research are: laser power, cutting speed and focal point position. Design of experiment (DoE) was used by implementing Box-Behnken design to achieve better cut qualities within existing resources. Mathematical models were developed to establish the relationship between the process parameters and the edge quality parameters. Also, the effects of process parameters on each response were determine. Then, a numerical optimization was performed to find out the optimal process setting at which the quality features are at their desired values. The effect of each factor on the responses was established and the optimal cutting conditions were found.