Integrated and concurrent approach for compound sheet metal cutting and punching

In sheet metal processing and manufacturing, there are a lot of small- and medium-sized job shops. These small- and medium-sized manufacturing companies have been facing keen competitive pressure in the market. This pressure has forced these companies to make every effort to shorten product development lead-time, improve production efficiency, approach high-quality standards, but at the same time cut down the costs. To meet the needs of these companies, this paper presents a compound cutting and punching production method supported by an integrated CAD/CAPP/CAM system in sheet metal manufacturing. Many existing commercial CAD/CAM systems are not suitable for this manufacturing method, especially under concurrent and global design and manufacturing environments. Some problems have to be solved before these CAD/CAM systems can be employed and integrated for this compound manufacturing method. This paper deals mainly with the solutions to solve some of these problems. The solutions include an integrated data integration platform based on Pro/INTRALINK and STEP, and a knowledge-based real time CAPP (RTCAPP) system for compound sheet metal cutting and punching. Within the presented CAD/CAPP/CAM system, some key modules have been developed. They are the automatic tool selection and manufacturing sequencing module, a shortest tool path optimization module, a cost estimation module and an automatic insertion of auxiliary path module based on knowledge bases. These modules will be addressed here.     

New integrated model to estimate the manufacturing cost and production system performance at the conceptual design stage of helicopter blade assembly

This paper describes a new integrated model development to estimate the manufacturing cost and production system performance at the conceptual design stage. A fully automated conceptual framework for design for manufacturing (DFM) has been developed. An integrated product process design concept using activity based costing is applied in this paper. The new integrated model consists of four sub-modules: the geometric parameters generation module, processing time estimation module, activity based costing (ABC) module and production system performance module. All of the input-output data flows of developed modules are fully integrated for automated manufacturing cost analysis and production system performance. A developed integrated model is very useful for designers or integrated product development team to make a decision for evaluating the design alternatives and trade-offs between design and manufacturing phases at the conceptual design stage. A case study for a composite helicopter rotor blade is included.     

Manufacturing system development framework using a data models driven approach

We report on a data models driven approach for the development of a manufacturing system framework. Relational data schemes are used for the creation of data models. A modular approach is adopted for the creation of complex manufacturing system configurations. Each module is created by selecting the appropriate resources from the data models and is represented as a standard module template in the module library for future use. Several modules can be integrated together through an automated guided vehicles system to model a complex manufacturing system. Each module is autonomous in creating and executing its plans, but cooperative with other modules to realize the system's overall goals. For effective control of parts in the system, an event-based simulation strategy is implemented. The developed algorithm can resolve the situations arising due to any deadlock or conflict during a simulation run. System data tables are regularly updated as and when an event occurs in the system. The updated information includes machine status, part location and status, and capacity status, etc. of all parts and resources. A case study comprising eight part types with five different flow patterns in a three-module system is taken to show the effectiveness of the proposed approach.     

面向地域文化创意产品设计的服务平台构建

目的探索面向地域文化创意产品设计的服务平台构建方法,通过强化设计服务供给,提升地域文化创意产品设计水平。方法以设计服务需求整合结果和一般设计流程为基础制定平台主体框架。主要分为地域文化设计资源整合子平台、设计辅助子平台和快速原型制造子平台三大模块,力求为多方面的设计需求服务。结论论述了平台主要架构和构建的重要节点,并将研究结果在实践中予以运用。经验证,为设计活动提供辅助服务的平台构建,能够有效地提升地域文化创意产品设计效率和水平。     

多学科集成下的老年智能产品设计研究

目的 基于多学科集成理论,分析老年智能产品设计现状,在了解老年用户群体对产品需求的基础上,进行设计实践创新方法研究。方法 通过阐明多学科集成方法中系统化、框架化、协同化、优化算法等理论,针对使用者、设计者双方进行分析,寻找出产品设计过程中存在的问题,在服务设计原则和多学科集成的理论支持下,进而推导出设计思路和方法。 结论 提出老年智能产品设计的基础是用户的操作体验和特定需求,设计过程涉及多学科、多目标;以“多目标实现”“多学科综合系统模型”“新技术融合”等应用实例,解释了如何解决产品设计过程中,由于用户需求复杂所产生的计算复杂性和选择复杂性等问题,优化了设计框架,归纳了设计信息,提升了设计过程的合理性、高效性和准确性。     

INTEGRATING PRODUCT DESIGN AND MANUFACTURING: A GAME THEORETIC APPROACH

One approach for increasing the quality of a product and the efficiency of its realization is to pay attention to the integration of product design and manufacturing. An integrated product realization process must be able to accommodate sequential stages of activity along a product realization time-line, independent information flow between stages, and trade-offs between various activities and factors. In this paper, a decision-based approach that is consistent with such characteristics is explored. This approach is anchored in game theory and a decision construct, namely, the Compromise Decision Support Problem. The merging of these two elements provides a mathematical and systematic basis for coordinating product design and manufacturing. This approach is illustrated via an example, namely, the redesign of a common component platform for a family of absorber-evaporator modules for absorption refrigeration, in order to reduce their costs and production times. The focus is on the method rather than the results per se.     

A methodology for design and reconfiguration of reconfigurable bending press machines (RBPMs)

Customer requirements have become very dynamic and unprecedented. A manufacturing paradigm called reconfigurable manufacturing system was initiated to adjust the physical machine entities. The main enabler of a machine structure’s reconfigurability is a modular design approach. The paper explains a function-driven object-oriented methodology for the design and reconfiguration of RBPMs. The complete method aims to optimise initial design of RBPMs, followed by subsequent design of RPBM modules which are stored in a module library so as to enable full-automatic reconfiguration of the RBPMs. The methodology is implemented on a pilot project to design a 145 ton bending capacity RBPM, with a maximum reconfigured length of 5?m and total height of 3?m. In order to deduce the design for the reconfigurable bending press machine, the reconfigurability needs were identified first, followed by the construction of a function tree for the machine. The function tree identifies the primary function for the RBPM, which is to bend sheet metal. The primary function is further decomposed to lower level functions until terminal functions are arrived at. The terminal functions are then used to identify the modules for the machine. The modules implement specific brunches of the machine functions.     

Agile manufacturing: Enablers and an implementation framework

Tougher competitive situations have led to increasing attention being paid to customer satisfaction, of which timely and customized services are the key concepts. As the product life cycle becomes shortened, high product quality becomes necessary for survival. Markets become highly diversified and global, and continuous and unexpected change become the key factors for success. The need for a method of rapidly and cost-effectively developing products, production facilities and supporting software, including design, process planning and shop floor control system has led to the concept of agile manufacturing. Agile manufacturing can be defined as the capability to survive and prosper in a competitive environment of continuous and unpredictable change by reacting quickly and effectively to changing markets, driven by customer-designed products and services. This article details the key concepts and enablers of agile manufacturing. The key enablers of agile manufacturing include: (i) virtual enterprise formation tools/metrics; (ii) physically distributed manufacturing architecture and teams; (iii) rapid partnership formation tools/metrics; (iv) concurrent engineering; (v) integrated product/production/business information system; (vi) rapid prototyping tools; and (vii) electronic commerce. A conceptual framework for the development of an agile manufacturing system and future research directions are presented in this paper. This framework takes into account the customization and system integration with the help of business process redesign, legal issues, concurrent engineering, computer-integrated manufacturing, cost management, total quality management and information technology.     

并行工程环境下成形铸件制造工艺CAD／CAE系统

并行工程在发展中提出了合理产品设计／工艺设计新概念，在此基础上我们研究开发了一个以传热，热流及应力模拟为核心的铸件制造工艺ＣＡＤ／ＣＡＥ集成系统，系统既可独立运行，又可与并行环境下的产品集成起来，达到同时优化产品设计及工艺设计的目的。目前该系统在多家工厂得到应用，并逐步商品化。     

基于Creo钣金模块的异型纸盒设计方法

目的研究异型纸盒以三维造型为基础完成二维展开结构的逆向设计。方法以Creo钣金模块为主要设计工具,分析不同类型异形纸盒展成二维图形的方法及规律。结果提出了适用于不同纸盒造型的3种钣金建模方法,总结了以长方体造型为基础的异型纸盒钣金件展平结果。结论通过设计案例证明,利用Creo钣金工具进行异形纸盒逆向设计可以降低设计工作对设计师技能的依赖程度,并可加快新盒型的开发进程。     

基于家居一体化的整体软装模块化设计研究

目的研究在家居一体化的形势下实现家居整体软装设计的有效途径。方法解析目前软装行业的发展状况和存在问题,以服务设计为导向,从用户需求出发,对产品标准化和设计模块化的特点进行系统分析,并且对影响整体软装模块化设计的产品结构、模块组合、资源配置和用户体验等多方面进行深入研究,探讨基于家居一体化的整体软装模块化的设计原则与应用策略。结论运用模块化设计原理,通过对产品平台建设和模块组合配置的研究,提出家居整体软装模块化设计的解决方案。     

A conceptual framework for the ubiquitous factory

To cope with today's industrial demands requiring (1) coverage of the whole product life cycle, (2) environmentally conscious manufacturing, (3) competitive sustainability manufacturing, etc., a new manufacturing paradigm should be developed. In this paper, we develop a conceptual framework for a new paradigm called ubiquitous factory (u-Factory) by applying ubiquitous computing technology to the manufacturing system. The u-Factory is based on our previously developed paradigm, called UbiDMR [1], meaning product design, manufacturing, and recycling via ubiquitous computing technology. The essence of u-Factory can be represented by three key phrases: (1) information transparency, (2) autonomous control, and (3) sustainable manufacturing. This paper comprises two parts. In the first part, we show the derivation procedure for the framework of the u-Factory using problem analysis of the current manufacturing system, design consideration and derivation of the architecture for the ubiquitous factory. In the second part, to demonstrate the validity and impact of the derived architecture, we develop the TO-BE model for manufacturing resource management. This is followed by a comparison with the AS-IS model.     

Manufacturing responsiveness through integrated process planning and scheduling

This paper describes a novel approach to improve manufacturing responsiveness, defined as the ability of a manufacturing system to make a rapid and balanced response to the predictable and unpredictable changes characterizing today's manufacturing environments. The approach aims at creating a dynamic environment that is capable of reacting to factory conditions and which has a significant impact on the reduction of cost, lead time and inventory. The concurrent engineering concept of information sharing to support all the product development phases is employed here. Techniques such as design for manufacture have been applied to the design-process planning interface. Efforts have been made towards eliminating the divisions between process and scheduling activities using the concept of resource elements, which are the exclusive and shared capability boundaries between processing elements in the manufacturing facility. A prototype integration system has been implemented consisting of a knowledge base with facility modelling functions, an intelligent feature-based design system, a featurebased process planning system and a simulation-based scheduling module.     

Optimizing cutting parameters in process planning of prismatic parts by using genetic algorithms

The determination of optimal cutting parameters, such as the number of passes, depth of cut for each pass, cutting speed and feed, which are applicable for assigned cutting tools, is one of the vital modules in process planning of metal parts, since the economy of machining operations plays an important role in increasing productivity and competitiveness. The present paper introduces a 'system software' developed to optimize the cutting parameters for prismatic parts. The system is mainly based on a powerful artificial intelligence (AI) tool, called genetic algorithms (GAs). It is implemented using C programming language and on a PC. It can be used as standalone system or as the integrated module of a process planning system called OPPS-PRI (Optimized Process Planning System for PRIsmatic parts) that was also developed for prismatic parts and implemented on a vertical machining centre (VMC). With the use of GAs, the impact and power of AI techniques have been reflected on the performance of the optimization system. The methodology of the developed optimization system is illustrated with practical examples throughout the paper.     

A novel approach to include sustainability concepts in classical DFMA methodology for sheet metal enclosure devices

Nowadays sustainable design is a mandatory requirement in the product development process. For this reason, design methodologies are addressed to establish a close relationship between environmental, social and economic impact indicators and product features from early design stages, especially in those features related to its manufacturing. In this paper, the design for manufacturing and assembly—DFMA methodology is adapted to sheet metal enclosure devices, integrating functional and component relationships to minimize particular sustainability indicators such as energy consumption, carbon footprint, number of parts, required amount of material, assembly time and manufacturing costs. Savings with the proposed method are achieved following specific sub-tasks oriented to define new simplified product components, considering changes in manufacturing processes and re-defining mechanical connections between parts. Traditional DFMA approaches consider manufacturing and assembly issues related to a reduction of product complexity and economic savings. The proposed method aims to examine the benefits in life cycle stages such as raw material consumption, service, maintenance, upgrading and end of life—EOL. The methodology is validated through a redesign of a sheet metal industrial clock, in which the sustainability impacts are calculated from a comparison of an existent product vs. a new product development. The implementation of the method in the case study demonstrate reductions of more than 25% in product mass, consumed energy and CO₂ footprint, and more than 50% in theoretical assembly time and product complexity. Sustainability indicators of the proposed method are selected from literature analysis and taking into account attributes of sheet metal enclosure devices.     

虚拟产品开发中的并行公差设计

并行公差设计能够有效解决VPD中的公差控制与公差分配问题，有利于VPD的全面集成以及面向加工和面向装配的实现。本文介绍了并行公差设计的内涵和特点，并提出了并行公差设计的系统结构。在此基础上开发的基于PDM的并行公差设计系统是虚拟开发平台的一个重要组成部分，已经通过863CIMS主题专家组的验收。     

A design advisor for sheet metal fabrication

Using data gathered over many years, people working in sheet metal fabrication have compiled lists of errors that are frequently made by designers in the field. These errors (or violations) are common to the design of sheet metal components used in a wide variety of products from computer chassis to automobiles. This paper outlines the efforts to use this information to aid in the development of a rule-based design advisor for sheet metal fabrication. The design advisor is a module of Promod-S, a concurrently engineered, application-orientated product modeler that is being developed by researchers at the Automation and Robotics Laboratory of the University of Massachusetts at Amherst.

The paper presents algorithms for both the identification and correction of design violations. The correction approach includes methods for updating an entire part after a feature has been modified.     

Process planning for sheet metal parts based on information management

Design and manufacturing processes and their mutual interaction are reflected by the Manufacturing Engineering Reference Model. Information management, as the kernel of this reference model, encompasses structures that reflect the information. The three information structures that are discerned refer to products, resources and orders respectively. Originating from the demand for Concurrent Engineering, augmented effort is invested in the integration of the different processes applied in the manufacturing cycle of products. This paper discusses the integration of design and process planning-which is one of the main topics in Concurrent Engineering-along with the demand for Design for Manufacturing. Emphasis is on the application of production method knowledge and design support, especially for sheet metal parts.     

基于J2EE的工业设计协同环境研究

分析了计算机支持的工业设计模式和J2EE平台特点及应用环境,从网络环境中构建协同工业产品设计系统的基本要求出发,提出了基于J2EE平台的协同工业设计体系结构,介绍了各模块的作用和相互关系,定义了协同工业设计过程模型,给出了协同设计信息的流转方式．     

Modelling and simulation of adhesive curing processes in bonded piezo metal composites

This work deals with the modelling and simulation of curing phenomena in adhesively bonded piezo metal composites (PMC) which consist of an adhesive layer, an integrated piezoelectric module and two surrounding metal sheet layers. In a first step, a finite strain modelling framework for the representation of polymer curing phenomena is proposed. Based on this formulation, a concretised model is deduced and applied to one specific epoxy based adhesive. Here, appropriate material functions are provided and the thermodynamic consistency is proved. Regarding the finite element implementation, a numerical scheme for time integration and a new approach for maintaining a constant initial volume at arbitrary initial conditions are provided. Finally, finite element simulations of a newly proposed manufacturing process for the production of bonded PMC structures are conducted. Thereby, a representative deep drawing process is analysed with respect to the impact of the adhesive layer on the embedded piezoelectric module.