An intelligent-agent framework for concurrent product design andplanning

This paper proposes a multi-agent framework to develop product design and planning using the concurrent engineering approach. The ideas in the framework draw on design-team behavior in many domains. The goal is to provide information that will help teams of designers, engineers and managers from various functional areas improve initial designs so that they satisfy a wider variety of concerns. Our model provides support to bring together constraints from the different team members in the development cycle. By integrating downstream constraints into the design phase, we reduce the need for redesign (due to design mistakes) later in the product development cycle. Our framework integrates a blackboard architecture with an intelligent agent (IA) network. Our methodology uses conflict-resolution (CR) techniques and design-improvement suggestions to refine the initial product design, and process plan generation and simulation to verify the manufacturability of the design. The contributions of the paper are threefold. First, our framework provides a more realistic way of modeling design teams by providing a way to model an individual team member's perspective as a segment of a continuum of task knowledge. Second, we identify the essential components of concurrent engineering needs, and develop a framework for integrating these components so as to ensure adequate coordination among the processes involved. Third, our methodology uniquely meshes together design constraints with factory resource considerations, so that the final product design is ensured to be feasible and manufacturable     

Effects of concurrent engineering on make-to-order products

An increasing number of manufacturing organizations are using concurrent engineering product development processes, which rely on parallel scheduling of activities throughout the product development cycle. This study examines the impact of such practices on product development time, product quality, and delivery leadtime. Using data obtained from structured interviews with product managers and engineers, six hypotheses are tested using a sample of 31 make-to-order (MTO) products from several industries. The results suggest that concurrent engineering may he appropriate for incremental innovation, but may have some “hidden costs” in the form of increased defects when applied to new “breakthrough” innovations. However, this strategy may be entirely suited to a specific customer segment that is willing to work with the manufacturer on debugging the product in the field. The study points out the importance of considering the hidden costs of concurrent engineering, and discusses the strategic implications of such decisions for technology managers     

A concurrent optimization methodology for concurrent engineering

The authors describe a methodology for making the decisions associated with the concurrent engineering of a product and its downstream held support. They adopt, for the overall metrics for evaluating these decisions, long-run system availability and life-cycle cost. The decisions that constitute the concurrent engineering effort can be categorized into three phases: designing the product; designing the manufacturing and logistics systems; and setting operations-control policies for parts production and field support. As an enhancement to well-established methods of coordinating decision makers in concurrent engineering and sharing data across different phases of design and deployment, they have developed a methodology that simultaneously makes the decisions that constitute these phases. This methodology is based on a dynamic programming model of these decisions which is robust and efficient when compared to manual methods of coordinating the concurrent engineering effort. They recommend its use as a decision support mechanism, not as a substitute for interaction among design-team members     

Is concurrent engineering always a sensible proposition?

Currently in the literature it is apparent that there exists a strong drive towards the employment of concurrent engineering as opposed to the serial progression of products through phases. In many cases there is much advantage to be gained from the early involvement of downstream activities such as the involvement of manufacturing in the early phases of engineering. This is the basis of the entire movement towards design for manufacturability. This note is a cautionary one which shows that the precise models, though rudimentarily simple, of the development process and its probabilities must be considered before statements can be made on the efficiency of one variety of engineering process over another; in other words, caveat emptor. Specifically, the authors show how this happens in a realistic environment and then propose a better alternative configuration that is a hybrid between serial and concurrent product design     

产品试验工程管理过程和方法

产品试验已成为产品寿命周期中一项重要的工程活动,对产品试验进行管理也成为产品寿命周期管理的重要内容之一。从产品试验管理的部门和职责、过程方法、资源等方面进行了阐述,分析讨论了产品项目中的试验程序、试验资源等方面的管理,以使试验过程得到有效的规划,并集成到方案论证、设计、研制、生产和保障阶段中．另外,还对相关应用技术的发展进行了展望。     

集成电路可制造性工程与设计方法学

集成电路可制造性工怀设计是近年来发展很快的研究领域，它集ＩＣ设计、制造、封装和测试过程为一体，在统一框图（即产品制造成本和成品率驱动下）下，对产品进行规划和设计，应用该设计可以大大缩短ＩＣ产品研制周期，降低制造成本，提高成品率和可靠性，本文将综述该领域的研究进展，并阐述进一步的研究方向。     

Optimizing the concurrency for a group of design activities

This research focuses upon the optimization of the concurrency between upstream product design activity and downstream process design activities in the concurrent engineering product development pattern. First, a new model of concurrent product development process, i.e., the design activity group model, is built. In this model, the product and process design activities are carried out concurrently with the whole design process divided into several stages, every two of which are separated by a design review activity. The design review activities may lead to design iterations at a certain rate of probability. Therefore, a probability theory-based method is proposed to compute the mean duration of the design activity group and the mean workloads of all the design and review activities, with design iterations taken into consideration. Then, the problem of concurrency optimization is defined mathematically, whose objective is to minimize the total costs for delay of design activity group completion time and unnecessary design revision workloads. Our research proves that the cost function is convex with respect to the concurrent (or overlap) degree between design activities and that it must have a minimum value at a unique optimum point. Based on this property, a one-dimensional search algorithm that is exponentially converged is finally proposed for solving the problem.     

On the use of yielded cost in modeling electronic assemblyprocesses

Yielded cost is defined as cost divided by yield and can be used as a metric for representing an effective cost per good (nondefective) assembly for a manufacturing process. Although yielded cost is not a new concept, it has no consistent definition in engineering literature, and several different formulations and interpretations exist in the context of manufacturing and assembly. In manufacturing, yield is the probability that an assembly is nondefective. To find the effective cost per good assembly that is invested in the manufacturing or assembly process, cost is accumulated and divided by the yield at the end of the process. This paper reviews and correlates existing yielded cost formulations and presents a new approach that enables consistent measurement of sequential process flows. This new approach defines the yielded cost associated with an individual process step (step yielded cost) as the change in the process's yielded cost when the step is removed from the process. This approach is preferred because it incorporates upstream and downstream information and because it provides a prediction of a specific process step's effective cost per good assembly that is independent of step order between steps that scrap defective product     

Simulation of fatigue distributions for ball grid arrays by the Monte Carlo method

Any approach to qualification of advanced technologies during product development must include an assessment of variation expected in product life over the life cycle. However, testing product design options in development, to approach an optimal design is costly and time consuming. Hence, simulation of product life distributions for virtual qualification can be a valuable tool to evaluate and qualify design options. This paper presents a physics of failure-based approach to virtual qualification of advanced area array assemblies against solder fatigue failure. The approach applies Monte Carlo simulation to evaluate solder joint fatigue life distributions, given material property variations and manufacturing capabilities. Preliminary results using the simple Engelmaier model as the basis of simulations are presented. Simulation results are compared to data accumulated from two test environments and two ball grid array product types. The results reveal some of the limitations of the Engelmaier model as a basis for simulation. They also show the potential of this approach to virtual qualification for design and manufacturing capability assessment in development.     

BGA器件焊接合格率的预测模型

在表面贴装技术(SMT)大规模生产过程中,如果能够对焊接合格率进行预测,无疑对提高SMT产品的生产率、产品可靠性及成本控制具有重要意义.以球栅阵列(BGA)器件为例,研究SMT焊接合格率的预测方法.通过统计分析,结合焊点成形软件的方法,建立了BGA器件焊接合格率的预测模型,运用该模型可以找出影响焊接合格率的制约因素.结合仿真技术模拟焊点形态,发现引起焊接缺陷各参数之间的关系,并提出相应的解决方案.     

RASSP Enterprise Technologies for Signal Processor Life-Cycle Support

Enterprise integration technologies are a key contributor to improving time-to-market, cost, and design quality by a factor, which is the goal of the DARPA Rapid Prototyping of Application-Specific Signal Processors (RASSP) program [1]. The Lockheed Martin Advanced Technology Laboratories (ATL) RASSP team developed a productivity improvement model, shown in Fig. 1, that indicates the relative contributions of various RASSP technologies to the overall improvement. Enterprise technologies address the entire 17% enterprise partition, and more than half of the 30% reuse and model-year architecture partition, thus accounting for at least 35% of the overall RASSP productivity improvement.The ATL RASSP approach to implement enterprise systems is to extend commercial technologies so the results are available to a broad base of potential users. Unlike current automation concepts which start at later stages of the development cycle, the RASSP enterprise system supports the entire signal processor life cycle. Core concepts of the enterprise system include:Tools and tool frameworks integrated into an enterprise environmentProgram execution control through workflowsIntegrated data management functionsDesign reuseConcurrent engineering team supportIntegrated design engineering and manufacturing.The model-year architecture, which enables users to rapidly, efficiently upgrade systems with new technology, is supported in the enterprise system by a robust reuse management system. Manufacturing interface and communication services elements of the enterprise system provide improved concurrent engineering support for distributed product teams. The enterprise system will be provided to commercial and aerospace users as products, including a reusable set of workflows for electronics design, commercial tools supporting the enterprise system environment, and utilities to enable users to customize the RASSP enterprise system for a particular organization or project.The enterprise system development cycle includes four build cycles with increasing capabilities. The ATL team completed the Build 2 implementation in May'96. This implementation supports the processes associated with detailed hardware/software design, architecture design, and trade-off analyses. It is being used at Lockheed Martin and multiple government sites for benchmarking and evaluation. Results to date indicate >5:1 productivity improvements in the manufacturing interface, and 5–10% improvements in design engineering, which is growing with increasing level of utilization.     

A decision analytic framework for evaluating concurrent engineering

This paper quantifies key issues with regard to concurrent engineering through the use of risk and decision analysis techniques that enable us to better understand, structure, and manage the design process. In concurrent engineering, the information structure of a design process does not usually imply the execution patterns of the corresponding design tasks. On the contrary, this gap between the information structure and execution patterns is the essence of concurrent engineering and its basic advantage over traditional sequential design. In this paper, we relate the structure of information flow in a design process to three different execution strategies: sequential, partial overlapping, and concurrent. The risks of excessive task iterations or redesigns associated with each execution pattern are probabilistically modeled. Risk and decision analysis methodology is used to determine the best execution strategy and the optimal overlapping policy for a set of activities given their information structure. Applying this theoretical framework to a real-world design application of an automotive cylinder block suggested a potential 18% reduction in development cycle time     

Utilizing cluster analysis to structure concurrent engineeringteams

The problem of structuring a concurrent engineering team was studied. This research considered various mathematical clustering approaches to group product development design tasks together, and then constructed cross-functional teams based on the task clusters formed from each approach, Resultant team structures were evaluated against each other, and against a traditional discipline-centered hierarchical structure. The goal of this effort was to develop a structuring methodology for concurrent engineering teams that would allow projects to be completed faster, and with a lower risk of project failure. Team structures were developed using alternative clustering techniques and different combinations of data as inputs into the clustering techniques. Clustering approaches included single linkage, complete linkage, average linkage, the centroid method, and Ward's method. Data sources were from the initial stages of product development, and included task risk levels, task precedence relationships, disciplines required, personnel available, task technical importance, task difficulty, task priority, component requirement interactions, and projected communication levels between design tasks. Additional analysis was done on the effects of multiteam assignments for critical personnel. Team structures developed using the average linkage clustering approach and a data set composed of projected communication levels between tasks and discipline requirements for each design task were found to support the development of shorter duration projects with lower risk levels     

浅议Qc080000对实现绿色制造的帮助

当今世界随着欧盟RoHS,WEEP和EuP等指令的相继出台和正式实施."绿色浪潮"来势汹汹,越来越苛刻的"绿色壁垒"将给企业带来严峻挑战.我国作为一个制造业大国,把"中国制造"推向"绿色制造"已迫在眉睫.但是,绿色制造涉及到产品生命周期的全过程,涉及到企业生产经营活动的各个方面,因而是一个复杂的系统工程问题.本文通过对...     

基于CE环境的产品信息建模技术及其发展趋势

产品的数字化和信息化是数字化制造业的基础,产品数字建模技术是体现未来制造业能否快速适应市场竞争的关键技术手段.本文通过对比分析产品语言建模、几何建模、特征建模和集成信息建模等方法的优缺点,阐述了基于CE环境的产品信息建模过程应满足的技术需求、实现方法及其发展趋势.     

The MMST computer-integrated manufacturing system framework

Computer-integrated manufacturing (CIM) is the harmonious connection, integration, and interoperation of automation equipment within a manufacturing facility. In a semiconductor wafer fab, this includes integration of the processing equipment with all of the supporting systems for product and process specification, production planning and scheduling, and material handling and tracking. Traditionally, CIM systems have been characterized as monolithic mainframe-based systems and/or inflexible islands of automation with limited interoperability. Today's manufacturing demands fully integrated dynamic systems which directly support the concepts of lean, flexible and agile manufacturing to high quality standards. These requirements drove the design of a new CIM system which was developed for the Microelectronics Manufacturing Science and Technology (MMST) program. This paper provides an overview of the MMST CIM system framework which is based on open distributed system and object technologies. The CIM system was demonstrated in a 1000 wafer pilot production run in 1993 which achieved world record cycle time, and is now being commercialized as part of the WORKS product family from Texas Instruments     

Quality engineering (Taguchi methods) for the development ofelectronic circuit technology

Most technology development engineers use traditional reliability engineering methods to calibrate the objective functions of their new systems to meet various marketing requirements. These methods are marginally effective in reducing failure rates. To fundamentally improve quality, the engineers need to focus on improving the robustness of the basic functions of their new product or process technologies and apply parameter design methods to make the basic functions approach the ideal functions under real conditions. These robust design activities should be conducted by research and development departments before actual products are planned. The objective is to improve the downstream reproducibility of new technologies. The technical development of an electronic circuit is used to explain this proposition     

Multiproject strategy, design transfer, and project performance: asurvey of automobile development projects in the US and Japan

Large manufacturers usually need to manage multiple projects in order to leverage their financial and engineering resource investments on new technologies and designs. The purpose of this paper is to explore the relationship between different multiproject strategies and project performance measured by lead time and engineering hours. The multiproject strategy in this study focuses on different ways of transferring core technologies and designs from one project to another within the firm. First, this paper proposes a typology of different multiproject strategies, which categorizes new product development projects into four types: new design, rapid design transfer, sequential design transfer, and design modification. Second, using survey results on 103 different new product projects at 10 automobile firms in Japan and the US, this study concludes that projects using the rapid design transfer strategy are the most efficient in terms of engineering hours. Only through rapid design transfer can a preceding design be transferred from a base project to a new project with effective task sharing among engineers and mutual adjustments between the two projects. This paper also discusses organizational requirements for managing rapid design transfer projects. Neither a pure project-team approach nor a functional approach seem appropriate for the management of concurrent multiple projects     

Quality-oriented-maintenance for multiple interactive tooling components in discrete manufacturing processes

In discrete manufacturing processes such as stamping, assembly, or machining processes, product quality, often defined in terms of the dimensional integrity of work pieces, is jointly affected by multiple process variables. During the production phase, the states of tooling components, which are measured by adjustable process variables, are subject to possible random continuous drifts in their means & variances. These drifts of component states may significantly deteriorate product quality during production. Therefore, maintenance of the tooling components with consideration of both their continuous state drifts as well as catastrophic failures is crucial in assuring desired product quality & productivity. In contrast to traditional maintenance models where product quality has not been well addressed, especially for discrete manufacturing processes, a general quality-oriented-maintenance methodology is proposed in this paper to minimize the overall production costs. In this research, the total production cost includes product quality loss due to process drifts, productivity loss due to catastrophic failures, and maintenance costs. The quality-oriented-maintenance model is built based on a response model linking process variables with multidimensional product quality. It can be obtained either from engineering analysis for specific processes, or from statistical design of experiments. Three typical multi-component maintenance models are investigated under the general quality-oriented-maintenance framework. A case study for a sheet-metal stamping process is presented to demonstrate the effectiveness of the proposed methodology.     

High Cycle Cyclic Torsion Fatigue of PBGA Pb-Free Solder Joints

In this study, a comprehensive experimental and numerical approach was used to investigate high cycle cyclic torsion fatigue behavior of lead-free solder joints in a plastic ball grid array (PBGA) package. The test vehicle was a commercial laptop motherboard. The motherboard was subjected to torsional loading and life tests were conducted. Using finite element analysis (FEA), the test assembly was simulated as a global model and the BGA component was simulated as a local model. Strains measured on the motherboard surface near by the BGA were used to calibrate the FEA models. By combining the life test results and FEA simulations, a high cycle fatigue model for the lead-free solder joints was generated based on the Coffin-Manson strain-range fatigue damage model. This model can now be used to predict the cycles to failure of BGA interconnects for new electronic product design under cyclic torsion loading.