Simulation-enabled casting product defect prediction in die casting process

In current casting industries, product development paradigm is shifting from traditional trial-and-error in the workshop to CAE-enabled simulation and ‘proof-of-concept’ by computer. The product development paradigm shift is thus from heuristic know-how and experience to more scientific simulation, evaluation, analysis and calculation. CAE simulation plays an important role in the new product development paradigm as it models the entire casting process and reveals the dynamic behaviour of the casting system in working conditions. In addition, the product quality panorama and product defects are explored via simulation in such a way that the root-causes of casting defects are pinpointed and the solutions to avoid them can be determined. In this paper, the CAE technology for casting process simulation is presented. The modelling of the casting process is first articulated and the detailed simulation issues are then described. The information related to the filling and solidification process and after-ejection behaviour are revealed by CAE simulation. Through case studies, how the CAE simulation helps identify and predict the process-related defects is illustrated and its efficiency is finally validated.     

CAD／CAE技术在金属饮料罐设计中的应用

介绍了CAD／CAE技术在某金属饮料罐的结构设计和成型模具设计中的具体应用。设计应用表明,将CAD／CAE技术应用于金属包装领域,有助于优化产品的结构与成型工艺设计,加快产品设计进程．缩短产品投放市场周期;同时,CAD／CAE技术的应用能提高产品性能,降低产品研发成本。     

Partner selection model for design chain collaboration

Due to increasing global competition and shorter new product life cycles, brand owners collaborate more often with design chain partners to bring a new product to market. This paper proposes a design partner selection model to minimise the overall design chain cost, taking into account communication cost, time-to-market, and quality. The model can be formulated as a stagecoach problem. Next, a dynamic programming algorithm is developed for this model to select the optimal partners through the design chain. Finally, a numerical example and a sensitivity analysis are presented. The results also reveal that design quality and manufacturing quality positively influence the total cost, and when brand owners need to speed up time-to-market to keep up with a competitor, the design quality will become less important.     

Allocation of manufacturers through internet-based collaboration for distributed process planning

The pursuit of lower cost, shorter time-to-market, and better quality has led to a shift toward global production in today's competitive business environment. This shift however, forces manufacturing enterprises to have separate design houses and manufacturing facilities. In general, design houses are located in the same regions as customers to enable them to respond to the rapidly changing demands of customers. By contrast, manufacturing facilities can be placed in regions in which production costs are lower. However, this physical and logical separation between designers and manufacturers (or between upstream manufacturers and downstream manufacturers) raises various integration issues. The present paper addresses two of these issues: the framework for representing the data necessary to communicate requirements and objectives of the designer, and the methodology for utilizing such data to optimize the business objectives related to production cost and quality. The proposed representation, collaboration framework, and methodology will enable design houses and manufacturing facilities to realize the benefits of global production and to accommodate the management of loosely integrated supply chains.     

Development of a product design and supply-chain fulfillment system for discontinuous innovation

Given the lengthy product development lifecycle process, high cost, and low success rate, many firms avoid considering discontinuous innovation strategies, in spite of their increase in frequency and importance in many markets. Even with advances in automation and technology, many of the techniques being utilised in product development are relatively unchanged, and the definition of discontinuous innovation itself lacks a structural component. To address this problem, the authors developed a methodology for generative customisation to implement discontinuous innovation. Using the emerging technologies of generative design and agent-based modelling, the authors developed a methodology to create product inventions and measure product innovations using a complex adaptive system (CAS) model. This appears to be the first model that represents a complex adaptive system environment to measure the success of discontinuous innovation in the development of a market equilibrium agent model.     

A methodology for the selection of assembly systems

The design of an assembly system for a particular product is a complex engineering effort involving many interrelated decisions. The wide range of alternative system configurations makes a detailed design of each alternative too expensive and time-consuming. In this work a methodology is developed which helps the decision maker by ranking possible alternatives according to ‘subjective’ cost/ benefit criteria.     

Evaluating the manufacturability of machined parts and their setup plans

Design-for-manufacturability is an approach that requires product designers to consider the manufacturing issues of a product concurrently with the geometrical and design aspects. This paper presents a manufacturability evaluation methodology that incorporates design, machining and work-holding issues. The evaluation is carried out in two parts. The first part is related to the machinability of the features of the part, whereas the second part is concerned about the fixturability of the part with regards to its planar faces. The methodology uses the fuzzy sets theory and the analytical hierarchy process method to evaluate the accessibility, orientation, dimensional tolerances, and surface finish specifications of a part. The former is used to model the various ill-defined boundaries of the criteria, while the latter allows for differences in opinions from designers/machinists to be incorporated into the evaluation process. The quantitative machinability and fixturability indices found can be used to evaluate designs and generate redesign suggestions. A setup plans evaluation module has been developed to determine the merit indices of setup plans for machining a part using these machinability and fixturability indices.     

Multiobjective robust optimization method for drawbead design in sheet metal forming

It is recognized that fracture and wrinkling in sheet metal forming can be eliminated via an appropriate drawbead design. Although deterministic multiobjective optimization algorithms and finite element analysis (FEA) have been applied in this respect to improve formability and shorten design cycle, the design could become less meaningful or even unacceptable when considering practical variation in design variables and noises of system parameters. To tackle this problem, we present a multiobjective robust optimization methodology to address the effects of parametric uncertainties on drawbead design, where the six sigma principle is adopted to measure the variations, a dual response surface method is used to construct surrogate model and a multiobjective particle swarm optimization is developed to generate robust Pareto solutions. In this paper, the procedure of drawbead design is divided into two stages: firstly, equivalent drawbead restraining forces (DBRF) are obtained by developing a multiobjective robust particle swarm optimization, and secondly the DBRF model is integrated into a single-objective particle swarm optimization (PSO) to optimize geometric parameters of drawbead. The optimal design showed a good agreement with the physical drawbead geometry and remarkably improve the formability and robust. Thus, the presented method provides an effective solution to geometric design of drawbead for improving product quality.     

温冷复合成形参数稳健设计优化研究

针对汽车杯形类活塞产品高品质、低成本的生产要求,提出了温冷复合成形参数多响应稳健设计方法,构建了基于信噪比的二阶满意度函数和质量损失函数关系式。结合正交试验,优化出最佳工艺参数组合,温成形温度为(795±5)℃,温锻制坯变形程度为0.45,冷挤压模具工作带为2.5mm,冷挤压模具圆角为7mm。经小批量试验考核表明,优化出的温冷复合成形工艺参数对活塞产品质量稳定性控制能力强,具备工程生产能力。     

Quality design of tolerance allocation for sheet metal assembly with resistance spot weld

Tolerance directly influences the functionality of the products and the related manufacturing costs, and tolerance allocation is of great importance for improving the assembly quality. However, the information required to allocate tolerances for complex 3D assemblies is generally not available at the initial design stage. In this paper, a new quality design methodology is developed, which makes use of both original design data obtained by the response surface methodology and the extra interpolation data obtained by the Kriging method. The finite element modelling is presented for the sheet metal assembly process as no explicit relationship of the variations for key characteristic points are available. The robust tolerances can be allocated based on the quality design model. A case study with the typical assembly process of the rear compartment pan and the wheelhouse is carried out in the paper, the tolerance allocation results show that the developed quality design methodology is capable of determining the robust manufacturing tolerance before assembly, which satisfies the product requirements. This method enables a robust tolerancing scheme to be used in the sheet metal assembly process.     

Computer-aided checking fixture design system for automobile parts

Checking fixture design is a complicated task requiring a strong professional background and rich practical experience. In order to enhance design efficiency and quality, this paper proposes a computer-aided checking fixture design methodology. The key issues include a new minimal volume bounding box generation approach for workbench design, a multi-objective optimisation algorithm of locator layout for location design, a multi-surface extension and transition method for checking components design and a flexible part library system to reuse standard parts and to assemble them automatically. As an implementation of the system based on the key methods, Checking Fixture Design Wizard for automobile parts, a plug-in on CAD software, is developed. Finally, a car door checking fixture design is taken as a case study to verify its feasibility and practicability.     

Destructive disassembly to support virtual prototyping

The design paradigm called virtual prototyping (VP) is important because of the need to manufacture products in a short period of time and in a cost effective manner. By replacing the building of physical prototypes for testing various design issues such as usability, life-cycle analysis, functionality and so on with so called “virtual models” on a computer and analyzing them, virtual prototyping is achieved. One of the design issues that has become increasingly important is the “design-for-disassembly (DFD)” paradigm. A well designed product that is easy to disassemble has the obvious advantages when it needs to be taken apart for service or end-of-life recycling. Therefore a design tool that can tie the DFD issues into a virtual prototyping system is of considerable interest. This paper attempts to address this particular issue in the virtual prototyping area: DFD as applied to VP. This paper presents an overview of a detailed DFD method. An algorithm that can be readily tied into a computer aided design system, therefore also useful for virtual prototyping, is discussed. Some implementation issues and an evaluation of the effectiveness of the DFD method currently employed are explained. Even though this research is still in its early stages, the paper presents a general framework of DFD methodology and its potential to be used as a virtual prototyping tool.     

汽车覆盖件设计全流程CAD/CAE系统开发与应用

为解决目前CAD/CAE系统中数据转换精度损失和设计变更引起分析模型重复建模的问题,基于UGSNX平台开发了面向汽车覆盖件设计全流程的CAD/CAE集成系统FASTAMP-NX,该系统完全集成于NX环境,并基于特征造型技术建立了设计和分析相统一的关联参数化模型,避免了数据转换引起的精度损失和重复建模问题.系统求解器基于有限元逆算法和改进的动力显式算法,可应用于产品设计、工艺设计和虚拟试模的全流程,真正实现了"设计-分析-修改-优化"的闭式循环,极大地提高了汽车覆盖件产品和模具设计与分析的效率.     

Environmental conscious product design using CAD and CAE

Environmental consciousness has been regarded as an important concept for survival in the contemporary scenario. Modern design engineers are in need of approaches for creating environmentally friendlier products. In this context, this article reports a case study carried out in an Indian rotary switches manufacturing organization. The existing components of rotary switch have been modelled using computer-aided design (CAD). Then, the sustainability analysis has been carried out for determining the environmental impact. This is followed by the optimisation of the components using computer-aided engineering (CAE). The environmental impact has been measured in terms of carbon footprint, energy consumption and air/water impacts. It has been found that the optimized components possess minimal environmental impact. The sustainability improvement after the implementation of the proposed approach has been computed. It could be inferred from the results of the case study that CAD and CAE could lead to the development of environmental conscious product designs with minimal impact to the environment.     

A cognitively based approach to computer integration for design systems

The kind of relationship a designer will have with a design assisting tool is dependent upon the kind of dialogue possible between the two, and any dialogue will be conditioned by the degree of mutual understanding existing between designer and assistant. In the first part of this paper we examine the methodology, currently prevalent in the computer-aided building design domain, that is supposed to address this problem: product modelling. We argue that product modelling is inherently incapable of fulfilling the goals that it sets itself, primarily because it is an attempt to move a methodology from, and appropriate to, a closed domain to an unbounded domain. In doing so, it fails to address the basic problem: it fails to provide a medium for dialogue. Dialogue entails mutual understanding; to support a dialogue between tools and designer, it is not sufficient for the designer to learn about the tool, the tool's designers must develop a strategy for enabling the tool to understand the designer. The second part of this paper comprises the theoretical background for a pragmatic strategy for classifying representations held by design agents by mapping the internal structures of differing representations of objects onto one another. Research in cognitive science has shown that such structure mappings can form the cognitive basis for certain kinds of classification decisions. We briefly describe ongoing work aimed at applying these insights in order to enable machines to classify, and thereby interpret, nonspecific design representations.     

基于系统集成思想的粉末成形工艺自动设计

研究了粉末压制工艺自动设计得以实施的难点和关键技术,建立了基于ＣＡＥ技术的粉末成形产品和工艺的ＣＡＤ／ＣＡＥ／ＣＡＰＰ集成系统,描述了系统框架和实施技术,并给同应用实例。     

汽车空调扭矩限制器结构设计以及仿真分析

目的解决汽车空调压缩机扭矩限制器成本高、产生断裂碎片、可靠性低、耐久性差等问题。方法采用CAE分析以及实物样品验证相结合的方法,从安全、降本的角度研究设计新型的扭矩限制器。结果 CAE分析以及试验验证均满足设计要求。结论新型扭矩限制器是安全可靠的,且成本低廉,该新型扭矩限制器有效解决了现有产品存在的安全、成本问题,为汽车的安全性提供一份保障。     

VLSI超大规模集成电路测试和验证的发展趋势

随着深亚微米级材料的应用，VLSI器件进一步推动了半导体技术领域的发展，传统的测试和验证方法已不能满足需要且成本较高，基于Core的系统级芯片要求芯片设计者必须改变以往的开发方式，以便缩短上市时间，扩大销售额。一种嵌入式的测试方法应运而生，它能使芯片设计者在较短的时间内生产出高质量的产品，提高利润、增加市场知名度，且大大减少了系统验证、检测和调试的时间。本文着重讨论嵌入测试技术，分析该技术对产品的上市时间、产品质量以及生产成本所带来的影响。     

Developing assembly line layout for delayed product differentiation using phylogenetic networks

Effective formation of product platforms helps adapt to product demand changes and decrease time-to-market and lead time. The product platform groups the core elements of product family members into a common module used to derive different product variants by combining it with different components. A new delayed product differentiation (DPD) platform network model, which applies median-joining phylogenetic networks (MJPN), is proposed. It is used for forming product platforms and determining the assembly line layout of modular product families. The MJPN is traditionally used for DNA sequences’ mapping, analysis, clustering and tracing evolutionary trends. The concept of assembly/disassembly modular platforms, whereby both assembly and disassembly of components are used to derive the final product variants from the platform, is utilised. The proposed model determines the required number and composition of a product platform and defines the DPD points. The developed dynamic assembly/disassembly platforms enhance routing and product mix flexibility due to having different platforms that can be used to produce the same product variant. A family of household kettles is used to demonstrate the application of the proposed model. A metric is presented for determining the effectiveness of a given platform in delaying the product differentiation, hence increasing the efficiency of mass customisation. The proposed metric, applied to the case study, demonstrated that the proposed platform formation model using MJPN is more capable of postponing the product differentiation point.     

A module-based thermal design approach for distributed product development

Today, market demand for smaller, more powerful consumer electronics is rapidly posing a major challenge to product design. Several issues have been identified as major factors that affect the quality, cost, and delivery of product design in the so-called distributed design project. To address these concerns, a structured design method is needed. This paper proposes a design framework that can moderate inconsistent performance of system components (modules) resulting from a lack of communication between design sites. Module interconnection parameters at a system level are determined using the behavior-coupling matrix and work distribution matrix; initial design target values (ITVs) for system boundary conditions are provided for each module design. Our results show that system decomposition using ITVs offers a suitable framework for designing a product, considering the overall system behavior where each module is independently designed at different locations.