A virtual prototyping system for rapid product development

This paper describes a virtual prototyping (VP) system that integrates virtual reality with rapid prototyping (RP) to create virtual or digital prototypes to facilitate product development. The proposed VP system incorporates two new simulation methodologies, namely the dexel-based and the layer-based fabrication approaches, to simulate the powder-based and the laminated sheet-based RP processes, respectively. The dexel-based approach deposits arrays of solid strips to form a layer, while the layer-based approach directly forms a complete layer by extruding the slice contours. The layer is subsequently stacked up to fabricate a virtual prototype. The simulation approaches resemble the physical fabrication processes of most RP systems, and are therefore capable of accurately representing the geometrical characteristics of prototypes. In addition to numerical quantification of the simulation results, the system also provides stereoscopic visualisation of the product design and its prototype for detailed analyses. Indeed, the original product design may be superimposed on its virtual prototype, so that areas with dimensional errors beyond design limits may be clearly highlighted to facilitate point-to-point analysis of the surface texture and the dimensional accuracy of the prototype. Hence, the key control parameters of an RP process, such as part orientation, layer thickness and hatch space, may be effectively tuned up for optimal fabrication of physical prototypes in subsequent product development. Furthermore, the virtual prototypes can be transmitted via the Internet to customers to facilitate global manufacturing. As a result, both the lead-time and the product development costs can be significantly reduced.     

MAG-EX: A magnetics fabrication expert systems focusing expert systems technology on improving quality control

This paper describes the development and experiences involved with creating a prototype application for the use of expert systems technology in manufacturing, specifically in quality control. The company described in the paper is an electronics manufacturer specializing in power supplies and amplifiers for military and commercial applications. It currently relies heavily on traditional manufacturing information systems technology. Quality control must meet DoD and other regulations and directly affects the bottom-line. As a potential expert system project, management felt as though product quality and the company as a whole could benefit from strategic development in Quality Assurance. The paper discusses the process, the difficulties, and the derived benefits to quality control from the development of an expert system application. Further, the paper reports on additional training benefits derived from the explanation capability of the expert system.     

An integrated manufacturing system for rapid tooling based on rapid prototyping

To reduce the time and cost of moulds fabrication, a novel integrated developing and manufacturing system of rapid tooling (RT) based on rapid prototyping (RP) is proposed. The architecture of system which consists of four building blocks: digital prototype, virtual prototype (VP), physical prototype and RT system, is presented. A digital prototype can be established by 3D CAD software packages or reveres engineering technique. A VP is employed to guide in optimization of the mould design and manufacturing process planning. A physical prototype, which is built using RP technology, generally serves as a pattern for producing RT. By integrating these building blocks closely, the system can aid effectively in mould design, analysis, prototyping, simulating, and manufacturing process development. Three typical cases are discussed in detail to illustrate the application of the system. It has been shown from a number of case studies that the system has a high potential to reduce further the cycle and cost of die development while minimizing error introduction. As a result, the integrated system provides a feasible and useful tool for companies to speed up their product development.     

A process for solvent welded rapid prototype tooling

Rapid prototyping is widely seen as an effective tool for compressing time to market for new products. The typical process followed by industrial and mechanical design groups is to model a new product in a CAD system, rapidly prototype the component parts, use the parts as patterns for RTV silicone molds, and then cast polyurethane prototype parts from the molds. These prototype components are an integral part of the simultaneous engineering process. With prototype components, engineers are able to design, implement, test, and refine the assembly systems for a product while production tooling for the components is being made. In this paper, we describe an experimental rapid prototyping process, known as solvent welding freeform fabrication (SWIFT), that is very well suited to the production of short to medium run tooling. The advantage of the process is that it is very fast and inexpensive relative to the traditional RTV silicone mold making process. The process also produces ABS or polystyrene molds which last considerably longer than RTV silicone molds. Process development details are provided in the paper and its application to a power tool component is described.     

Digital twin-driven manufacturing equipment development

Currently, expectations of shorter time-to-market and improved product performance are placing greater demands on manufacturing companies. However, the optimization and redesign work between the design stage and the prototype design and manufacturing stage in the traditional product development process lengthens the required product development cycle time (which lasts up to several years in extreme cases). The manufacturing phase for the physical prototype of the product is especially time-consuming and costly. The above reasons make the common product development process increasingly unable to meet the demands of market needs. Motivated by this need, the digital twin (DT)-driven manufacturing equipment (ME) development method is studied in this paper. This method contains three main core elements of the design method based on axiomatic design (AD) theory, the construction of DT models related to ME development, and DT-based validation analysis. The advantage of this method is that it can incorporate the physical prototype manufacturing stage into the digital space with the high-fidelity model provided by the DT technology, which ensures the confidentiality of the design scheme validation while freeing it from the physical prototype stage. This avoids the cost of physical prototyping, shortens the product development cycle, and improves the efficiency of new ME development. At the end of this paper, a case study of the development of a virtual machining dynamic performance test bench (VM-TB) is carried out to show the implementation flow of this proposed method, and its operability and effectiveness are verified.     

Error-based segmentation of cloud data for direct rapid prototyping

This paper proposes an error-based segmentation approach for direct rapid prototyping (RP) of random cloud data. The objective is to fully integrate reverse engineering and RP for rapid product development. By constructing an intermediate point-based curve model (IPCM), a layer-based RP model is directly generated from the cloud data and served as the input to the RP machine for fabrication. In this process, neither a surface model nor an STL file is generated. This is accomplished via three steps. First, the cloud data is adaptively subdivided into a set of regions according to a given subdivision error, and the data in each region is compressed by keeping the feature points (FPs) within the user-defined shape tolerance using a digital image based reduction method. Second, based on the FPs of each region, an IPCM is constructed, and RP layer contours are then directly extracted from the models. Finally, the RP layer contours are faired with a discrete curvature based fairing method and subsequently closed to generate the final layer-based RP model. This RP model can be directly submitted to the RP machine for prototype manufacturing. Two case studies are presented to illustrate the efficacy of the approach.     

Price quotation methodology for stereolithography parts based on STL model

Rapid prototyping (RP) service bureaus or providers are always facing the urgent price quotation requirements for RP parts from customers in today’s competition market. This paper presents two effective methodologies of the price quotation for stereolithography (SL) parts based on STL model. A model of price quotation for the RP part was presented. Furthermore, the calculation of manufacturing cost for the SL system was also discussed in detail. Two quoting approaches which include the rough quotation based on weight and precise quotation based on build-time were proposed to determine the price quotation for SL parts. A new algorithm of predicting build-time of SL parts was put forward to implement the precise quotation. The algorithm incorporates the geometrical features drawn from the part’s STL model and the value of support structures determined by a statistical method. The proposed quotation methods have been employed to develop a web-based automated quotation system that can provide instant and accurate price quotation for SL parts to support effectively the RP&M service. The application results of a number of actual cases show that the methods can satisfy the engineering requirements of price quotation at the early stage of product development.     

Developing a quantitative intelligent system for implementing concurrent engineering design

This research focuses on the development of a quantitative intelligent system for implementing concurrent engineering design. The paper first discusses the task of concurrent engineering design and the basic requirements for conducting integrated concurrent engineering design. The proposed quantitative intelligent system approach combines qualitative reasoning, based upon design and manufacturing knowledge, and quantitative evaluation and optimization, conducted using design information and manufacturing data generated in the knowledge-based reasoning. The method allows considerations on non-operating principle aspects of a product to be incorporated into the design phase, such as manufacturing, maintenance, service, recycle, etc., with an emphasis on production costs. The proposed method serves as a convenient software tool for gathering information required in the concurrent engineering design process and integrates tasks from different parts of the product development life cycle, particularly function design, manufacturability analysis and production cost estimation. A prototype software system is developed based upon this method using Smalltalk-80. In the prototype system, concurrent engineering design is carried out by: (1) describing and representing design requirements; (2) generating feasible design candidates and evaluating their design functions; (3) representing design geometry; (4) finding the associated production processes and predicting the production costs of each feasible design; and (5) identifying the costeffective design that satisfies given design requirements and requires minimum production costs.     

Seeking intelligent product development—an integrator environment based on STEP

Rapid Prototyping (RP) is an emerging technology with different applications in the cycle of product and process development used during the conceptual and specification phases. To support it, the usage of a Data Base Management System (DBMS) and an Expert Systems (ES) are important to manage the data, support the identification of errors and check product conformance and production viability during this cycle, seeking intelligent product development. The underlying concept of RP and ES is very straight forward, but still exists a major problem that concerns the integration in the CAD/CAM environment. CAD data can have a variety of formats depending on the model used in the CAD system, as well as on ES' data and knowledge structure, that usually relies on the expert system shell's where it was developed. To support and speed up the integration process of these tools in a manufacturing environment, is essential to have an integrator environment where a standard is adopted for the data and knowledge exchange process, providing the software applications with a neutral format interface, becoming these tools open and standard compliant, ready to be used in any other standard environment. UNINOVA, in the scope of European and National projects, developed a STEP-based Platform for Integration of applications (SIP) to support and aid the software integration in industrial environments using the standard ISO10303-STEP, already used in different industrial domains. This paper addresses the integration aspects using STEP within industrial environments from the technical point of view, and proposes an architecture and a toolkit for the integrator environment, highlighting the implementation efforts required to have RP technology, ES and DBMS focused towards a STEP-based intelligent product development.     

A methodology to incorporate product mix variations in cellular manufacturing

The identification of part families and machine groups that form the cells is a major step in the development of a cellular manufacturing system and, consequently, a large number of concepts, theories and algorithms have been proposed. One common assumption for most of these cell formation algorithms is that the product mix remains stable over a period of time. In today’s world, the market demand is being shaped by consumers resulting in a highly volatile market. This has given rise to a new class of products characterized by low volume and high variety. To incorporate product mix changes into an existing cellular manufacturing system many important issues have to be tackled. In this paper, a methodology to incorporate new parts and machines into an existing cellular manufacturing system has been presented. The objective is to fit the new parts and machines into an existing cellular manufacturing system thereby increasing machine utilization and reducing investment in new equipment.     

Hybrid rapid prototyping system using machining and deposition

Many rapid prototyping (RP) systems are commercially available, and others are introduced daily. RP has proven to be an effective tool for dramatically reducing the time and expense involved in the realization of a new products and for overcoming the bottlenecks of existing manufacturing processes. However, its fields of application are currently saturated, and the emphasis has moved towards using RP for short-run manufacture. The current need is for a technique that will produce finished parts of the required quality in the shortest possible time, and which meet this need, the focus now falls on improvements in production speed, accuracy, variety of materials, and cost. For these practical reasons, we concentrated on a new form of hybrid-RP system, which performs both deposition and machining in a single station. Our proposed system meets the requirements of material deposition (RP) and material removal (CNC) at the process planning and manufacturing level. We believe that this new production system, which incorporates a combined RP concept, offers an optimum manufacturing solution by adopting the advantages of the RP and CNC systems. In this paper, we describe the system architecture and the fabrication process in detail and present the framework of the process planning system and the concepts of the geometric algorithms involved in developing such an environment.     

Using electronic textiles to implement an acoustic beamforming array: A case study

Highly-automated textile manufacturing equipment has the potential for integrating electronic components into fabric in a low-cost process. These electronic textiles (or e-textiles) have a wide range of potential applications in wearable computing and large-area applications, including medical monitoring, assistance to the disabled, and distributed sensor networks. This paper discusses the design and implementation of a large-scale e-textile that functions as an acoustic beamforming array. The paper conveys the implementation experience and gives results gathered from the prototype. Further, the primary implementation issues and guidelines for future development are identified.     

Microfabrication of ceramic microreactors

 Ceramic microreactors can be used for applications that cannot be covered by metal or polymer systems, because special material properties, such as high thermal and chemical resistance are required. However, application of ceramic microcomponents often fails due to the time-consuming and costly manufacturing of components with patterning details in the micrometer range. A promising solution to this problem is a rapid prototyping process chain. It offers a fast and precise fabrication of ceramic components down to the micrometer range by combining stereolithography and low-pressure ceramic injection molding. Its fast and flexible tooling allows rapid product development and manufacturing of ceramic components as functional models or in small series. For use in chemical microreaction technology, a modular ceramic microreactor with inner dimensions in the sub-millimeter range has now been developed by means of this process chain.     

Knowledge acquisition techniques for feature recognition in CAD models

Automatic Feature Recognition (AFR) techniques are an important tool for achieving a true integration of design and manufacturing stages during the product development. In particular, AFR systems offer capabilities for recognising high-level geometrical entities, features, in Computer-Aided Design (CAD) models. However, the recognition performances of most of the existing AFR systems are limited to the requirements of specific applications. This paper presents automatic knowledge acquisition techniques to support the development of AFR systems that could be deployed in different application domains. In particular, a method to generate automatically feature recognition rules is proposed. These rules are formed by applying an inductive learning algorithm on training data consisting of feature examples. In addition, a technique for defining automatically feature hints from such rule sets is described. The knowledge acquisition techniques presented in this study are implemented within a prototype feature recognition system and its capabilities are verified on two benchmarking parts.     

A decision support system for automotive product planning and competitive market analysis

A decision support system (DSS) for automotive product marketing, design and manufacturing in China is presented in this paper. The DSS is developed as a tool to support product planning, competitive market analysis, supply chain analysis and subsequent manufacturing systems planning and deployment. The system consists of a number of automotive related databases which provide information about manufacturers' performance in each market segment as well as production information of all existing market players in the Chinese auto industry. Product planning, one of the key modules of the DSS prototype, is highlighted in this paper. It supports decision makers in determining suitable strategies for market entry by analyzing existing competitors' status, growth estimation of each market segment, and competitive market analysis for new vehicle products. A case study for new market entry is included here to demonstrate the feasibility and effectiveness of the proposed methodology.     

Collaborative virtual prototyping of product assemblies over the Internet

Product assembly design is a complex activity involving collaboration between several designers. Currently, many manufacturing firms out source the design and development of different portions of a product to different suppliers. Due to the absence of an integrated tool for collaborative product assembly design, designers currently follow an indirect approach. This makes collaboration an unorganized and inefficient activity. This paper discusses the architectural novelties and design considerations utilized to develop an integrated collaborative assembly design tool. Further, the scenarios of using such a tool are discussed in detail. This discussion highlights how the tool contributes towards making collaboration an organized and efficient activity and enables designers to rapidly design and prototype the product assembly.     

Engineering Bereitschaft as an enabler for concurrent engineering

Industrial companies observe a general trend towards more customised products and shorter product life cycles. Furthermore, the market demands shorter lead-time and high-quality products at a competitive price. Concurrent Engineering addresses these challenges. Product modelling is a key aspect of the Concurrent Engineering literature. One problem with the product modelling literature is that it tends to assume that product development always is revolutionary. Very often product development is evolutionary and it means that product modelling should have a major emphasis on reuse. In this paper it is suggested that industrial companies should develop an engineering development Bereitschaft (preparatory engineering knowledge) as an approach to Concurrent Engineering and product modelling. To develop such an engineering development Bereitschaft, a company must develop company generic product models. This paper will describe experience from a shipyard where an object-oriented product model of a double hull supertanker and a product configurator prototype has been developed. Configuration of the steel structures in a ship and the succeeding productivity evaluation can in that way be done within a week. Such a fast cycle time allows for multiple iterations in search of a “good” design.     

兰代化纤厂CIMS应用工程之实践

兰化化纤厂ＣＩＭＳ应用工程是８６３／ＣＩＭＳ推广应用项目之一，该工程的第一阶段业已如期完成并通过验收。该厂的生产过程属于连续流程型，工程实施中突出地显现出流程ＣＩＭ的特点。有别于离散生产型，本文首先给出只包含生产实施和管理信息两个应用分系统的体系结构的设计。文中在介绍了第一阶段工程所完成的工作后，结合快速原型法实验，着重介绍在ＣＩＭＳ工程中应用Ｃｌｉｅｎｔ／Ｓｅｒｖｅｒ体系结构及使用先进开发。具开发软件的初步经验；文章中还特别介绍了在工程实施中要充分重视人和组织在ＣＩＭＳ中的地位，先期工作中就着力加强企业管理模式重构的研究与设计，并积累了有益的经验。     

e-CAPP: A distributed collaborative system for internet-based process planning

Advances in distributed technologies have enabled engineers to communicate more effectively, collaborate, obtain, and exchange a wide range of design resources during product development. Shared internet-based virtual environments allow experts in remote locations to analyze a virtual prototype, together and simultaneously in centers in which the product is being developed.This paper presents a system for distributed and collaborative environment which could assist manufacturing enterprises and experts in discussing, suggesting, evaluating and selecting best process plans for family of manufacturing parts. The represented e-CAPP system enables the implementation of expert knowledge in an appropriate knowledge repository. The knowledge from this repository is integrated into intra-company CAPP systems and used while generating process plans for new products. The proposed internet-based collaborative environment, dedicated to distributed process planning, is yet another step in the direction advancing of distributed manufacturing.