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喜歡就充值下載吧。。資源目錄里展示的文件全都有，，請(qǐng)放心下載，，有疑問(wèn)咨詢(xún)QQ:414951605或者1304139763 ======================== 喜歡就充值下載吧。。資源目錄里展示的文件全都有，，請(qǐng)放心下載，，有疑問(wèn)咨詢(xún)QQ:414951605或者1304139763 ======================== Engineers CAx educationits not only CADC. Werner Dankwort, Roland Weidlich*, Birgit Guenther, Joerg E. BlaurockUniversity of Kaiserslautern, Research Group for Computer Application and Engineering Design, P.O. Box 3049,Kaiserlautern 67663, GermanyReceived 30 January 2004; accepted 23 February 2004AbstractThe general product development can be divided into three phases: creative, conceptual and engineering phase. All phases of the completelife cycle of a product are supported by various IT-systems often called CAx1-systems. Therefore CAD-education should be extended toCAx-education and pay attention to all phases of the life cycle.When looking at todays process chain many different jobs related to CAx can be identified. All of them require different levels ofknowledge about subjects like information technology, design procedures or CAGD2-functionalities.The methods to teach those subjects vary from simple autodidactic, via computer supported training methods to interactive person toperson training. In industry, the training methods are primarily depending on the companys size and branch. The bigger the company is, themore complex are the training methods and the more specialized is the CAx-education.Enterprises specialised on CAx-training but also in-house education departments are concerned. Other possibilities for CAx-education areinternships, technical colleges and universities. All of those suffer from the complexity of the subject and result often in broad but superficialeducation.Apart from knowledge about CAx-systems and their usage, the students have to learn also about the organisation of the CAx-process andits structures including the cooperation of enterprises.Following these experiences the students or employees will at first be trained in fundamental CAS/CAD/CAM. In a second step they willattend special courses for PDM, Data exchange, FEM, or others. On higher level there will be courses dealing with PLM3, process- andcompany networks, with future trends and techniques. During the whole education the application aspect has to be dominant.q 2004 Elsevier Ltd. All rights reserved.Keywords: CAx job profiles; Human factors; Training methods; CAx education in industry; CAx education in universities1. MotivationIn a newsletter of the year 1999 from Solid Works thefollowing question was raised: “What is the most importantlearning objective?” The answer given was “To teach thatdesign is a process!” Later on in this newsletter it was saidthat engineering education is supposed to educate engineersin how to think in the modern world of product design andmanufacturing 1What does this mean for CAD-education in industry, atschools and universities? It certainly does not mean thatCAD-education is only restricted to teaching solid orsurface modelling. The task is quite more complex: thestudent or technical employee has to learn about thecomplete development process under the aspect of Compu-ter Aided Product Creation.2. A brief history of CAD-systemsModern CAx-systems have various roots: The Automatic Programming Tool (APT) developed byRoss at MIT in the 1950s to control machinesnumerically. This can be regarded as the precursor ofmodern CAM-systems. The early computer aided drafting systems (likeCADAM from Lockheed Martin) were developed to0010-4485/$ - see front matter q 2004 Elsevier Ltd. All rights reserved.doi:10.1016/j.cad.2004.02.011Computer-Aided Design 36 (2004) author. Tel.: 49-631-205-3686; fax: 49-631-205-3872.E-mail address: weidlichmv.uni-kl.de (R. Weidlich).1CAx: Summarised CAD, CAM, CAS, CAQ,2CAGD: Computer Aided Geometric Design3PDM:ProductDataManagement,PLM:ProductLifecycleManagementreduce time and money by replacing the conventionaldrawing board in the 1970s. The early systems for the creation of sculptured surfacesoriginally were developed for the automobile and thehelicopter industry. The motivation for this developmentwas not the reduction in time but a distinct 3D-representation of sculptured surfaces which then couldbe used for NC-milling. This 3D-surface representationcould not be created with conventional 2D-drawings andcut sections. Computer Aided Engineering by Finite-Element-Methods began in the 1960s with Nastran, followed byMarc and Ansys in the 1970s.From these roots more and more tasks in the designprocessweresupportedbyCAx-toolsduringthelast30years.Starting with drafting and surfacing also classical mechan-ical design was replaced by 3D wire frame, solid modellingandparametricandfeaturebaseddesign.Todaythecompleteproduct creation process, including production preparation,is completely running with CAx-techniques. According tothe various application fields different CAx-systems weredeveloped, named by different CAx-methods: ComputerAided Styling (CAS), Computer Aided Aesthetic Design(CAAD), Computer Aided Conceptual Design (CACD). Allthese technologies are covered by the expression ComputerAided Design (CAD). Two very important CA-fields werehistorically developed almost independently: ComputerAided Manufacturing (CAM) and Computer Aided Engin-eering (CAE). The last is mainly used in a limited sense forsimulation and Finite Element Analysis. Although startingindependently these technologies soon asked for input-datafrom CAD, I-DEAS, developed in the mid 1970s has its rootin the link of CAD and FEA.With the growing integration of these CAx-tools the dataand information management became more and moreimportant. Nowadays the complex network of CAx-systemsand their various data cannot be handled without ProductData Management Systems (PDMS). They are regarded asthe backbone of modern product development and nowextended to support the whole product lifecycle. This over-all information management leads to the concept of ProductLifecycle Management (PLM).Education concerning Computer Aided Product Cre-ation still does reflect this history: Students or engineersusually start their education with 2D-systems. Subsequentlythey are introduced to 3D-modelling. Further on they arefamiliarized with parametric and variational design. Parallelthey have to be trained in PDM- or PLM-systems to handleall the CAx-data.3. Todays process chainIn an exemplary simplified process chain (see Fig. 1) it isshown that CAD is only a part of the product developmentprocess. This process begins with an idea, requirements andspecifications for the product and ends with the serialproduction, customer after sales service, recycling, scrap-ping and disposal. CAD is embedded in the developmentprocesstogetherwithmanyotherCAxtechnologies.InorderFig. 1. General process chain of product development 2.C.W. Dankwort et al. / Computer-Aided Design 36 (2004) 143914501440to avoid unnecessary loops the engineer has to haveknowledge of the surrounding process steps as well as thekind and quality of data, respectively information, theyproduce or require. The knowledge about the previousprocess steps is to maintain the design intend, the knowl-edge about the following process steps is to guarantee theirfeasibility. In addition to this economical aspect the qualityof the product describing information has to be taken intoaccount.The modern product creation process proceeds moreand more as a virtual product generation process.Keeping in mind that the processes are characterized bySimultaneous Engineering (performing different processsteps at the same time) and Concurrent Engineering(developing neighbouring components in parallel), it isobvious, that an enormous amount of data produced has tobe handled by an efficient product data managementsystem (PDM). Two facts increase the complexity of thesituation: For different tasks within one or various process stepssometimes quite different CAx-systems have to be usedwith quite different data models. In modern industry a network of suppliers is involved,often working with different systems or differentversions of the same system.Therefore not only CAx-data exchange with dataconversion is a key task for successful development andproduction processes but also the complete supplierintegration.4. CAx people: various job profilesWhen looking at the history of CAD, the first users ofCA-tools in the 1970s were CAD-draftsmen and CAD-surface designer for car bodies or helicopter shells (todayoften called surfacer). Already in the 1970s the surfaceswere used directly for NC-milling of surfaces, while theFEA-engineer used the CAD-geometry as input.Draftsman and surfacers were trained primarily bysystem suppliers and/or by an in-house CAD-technician.These CAD-technicians often have been pilot users,trainers, and in-house system supporters at the same time.These pioneers made the new technique presentable andreduced prejudices, which had been raised by the conven-tional development.With the growing capabilities of the CAD-systems in thefirst half of the 1980s the number of different CAD peoplegrew. In the 1990s the scope of CAx-tools increased andtoday CAx-technology is more or less standard. Nowadaysthe intensive usage of CAx-technologies can be regarded asa precondition for any competitive company. As aconsequence the various tasks cause various jobs. Followingthe process chain there are (see Fig. 1): Stylists, who work manually, sketching and modellingwith clay, but also more and more with CAS-systems likeALIAS Surfacers, who transfer the shapes, designed by thestylists, to CA-Class-A-surfaces. They use specialsurface-systems like ICEM-Surf or in former timesSTRIM100. CNC-Model makers, who use CAM-techniques togenerate physical models from CAS- or CAD-data.This is done to transfer the shapes from the virtualworld to the physical world. To fill the gap between a manually optimized physicalmodel and the required CAD-surface description aspecial task is necessary: The surface reconstruction orreverse engineering (of shapes)In the field of standard engineering design there are theCAD-designers or CAD-engineers, who are working with3D-systems. According to their tasks, working fields and thelevel of CAD-application they are using wire frametechniques, surface-systems and/or solid modelling. Now,with introduction of more sophisticated design techniquesand with the increasing information, which is stored in aCAD-model, many fields of CAD-applications and relatedspecial job profiles can be distinguished: Component designers.They are in charge of the design ofspecial components of the product. Engineers for Parametric-Associative Design CAD-designers for tools and quality aids. Process planers Manufacturing simulators CA-plant lay-outersParalleltotheCAD-designthesimulationofproduct properties is another important task in the productdevelopment, which gives another job profile: Engineers for simulation, analysis and calculation. Togenerate reliable results they usually are highly special-ized on certain tasks. Consequently this job profile couldbe further structured.In former times these engineers for simulation oftenworked in isolated departments, starting the analysis whenthe design had been preliminarily finished. Nowadays thesetasks are completely integrated in the design department andgo along with the design. At the moment there is a tendencythat the engineers perform a preliminary analysis withintheir CAx-system to evaluate their design.This list of people and tasks involved in CAx can becontinued, all of them need at least some CAx-knowledge: Specialists for CAx-graphics generation Clerks within the purchasing departments for arrangingcontractsbetweenOEMandthesubcontractorsC.W. Dankwort et al. / Computer-Aided Design 36 (2004) 143914501441and suppliers. SW-design and SW-implementation Application SW definition CAx-systems in operation CAx-system testing and SW-quality control Computer centre and network operation Information management CAx-data exchange: development and operation ofSW-toolsThese examples show that there is a variety of differentjobs, each needing different know-how in the differentfields. Some examples are given in Fig. 2.Industrial experts estimated, that for one CAD-work-station about 10 other workstations are used in subsequentactivities like viewing etc. 3.5. The Human Factor and the environmentThe different knowledge, which is needed for or which isgained in the different jobs, is one aspect. Another veryimportant aspect in training people for their CAx-job is thehuman factor. There are three points which have to beconsidered: The past, the education and the experience of a person The human potential, the ability to fulfil the tasks ofmodern product development with CAx- and InformationManagement tools. The environment in which a person has worked beforeand in which it is going to work next.Each of the points above will be briefly described in thefollowing, already showing the complexity of modern CAx-education and that there is nothing like a standardizedCAD-education.5.1. The past, the education and the experience of a personEach person has a different background and, as his/hermind is strongly influenced by it, the way of thinking andlearning will be different from person to person. Anexample: In former times it was a strenuous task to makedesigners, who had worked many years at drafting tables,use a CAD-system efficiently. For them this meant toapproach problems in a completely new way. But theexperience, which was gained by solving problems theclassical way, often got lost. It could not be transferred toyoung engineers, who started their career on CAD-systems.This example shows one of the duties of CAx-education:To teach also some design methods used in former (pre-CAD-) time to make users aware of different ways ofthinking and of approaching problems in order to avoid riskslike: The restriction of the thinking to the limits given bythe capability of the IT-tool in use.5.2. The human potentialThis second aspect is more sensitive than the first one. Itis fact, that not all people have the same creativity,efficiency and flexibility. Much research has been done onthis matter, but it will go far beyond the scope of this paperto go into details here. The relation between number ofpeople on one side and skill, potential on the other side isoften similar to the classical Gaussian distribution (seeFig. 3) 4. People of high capability and efficiency shouldbe related to the right hand side of such a distribution.Training them on a CA-system will take very short time andsuch students or employees will work with high productivityin a very short time. These are typical pilot-user, which areof highest importance for the break through of CAx-technology in companies.Most of the engineers may be considered to be on theaverage. Current group training methods usually focus onthis majority. The effect will be, that some people in thislarge group are swamped by the speed and content of thetraining, while others are unchallenged by it. The praxis inindustry shows that the demands on engineers for themodern parametric-associative design often cannot befulfilled after standard training. But there are also peoplerelated to the left side of the Gaussian distribution, who needmore efforts in training to become a CAx-engineer then theaverage. No standard procedure can be proposed here. But itFig. 3. The Gaussian distribution.Fig. 2. Portfolio of the CA-landscape in an enterprise.C.W. Dankwort et al. / Computer-Aided Design 36 (2004) 143914501442is a challenge on personnel leadership to find good solutionsfor anybody.5.3. The environmentAdditionally to the two points described before theenvironment of a CAx-user is important for his knowledgeor training. The enterprise culture may support or prevent aperson to show lack in knowledge, to ask someone for help.This aspect may be of more importance than technicalfacets, like different design standards in the differentcompanies, e.g. of creating a CAD-model. Thus an engineergoing into a new company for the same job not only has tobe trained in new standards but also may be faced with adifferent kind of team culture.6. Depth of the training and responsibilityThe curriculum of the CAx-education can be divided intodifferent fields of knowledge and into different specialis-ation of knowledge. The fields of knowledge are alreadyshown in Fig. 2. The specialisation of knowledge means therelevance of a certain knowledge for a given task or job. Inthe following it is distinguished between three categories,analogue to the common terms of knowledge: General CAx-knowledgeThis kind of CAx-knowledge is the basis for furtherspecialized knowledge. Each person involved in modernCAx-technology should have this knowledge. Specialized CAx-knowledgeThis knowledge is common to all the people workingat a certain job. Every CAx-Designer working with thesame software in the same branch should have the samespecialised knowledge. Specialist CAx-knowledgeThis knowledge highly depends on the actual job andthe company the person belongs to. It is mostlyconnected to the structure and procedures which arecommon in this company. Specialist knowledge can bein-depth knowledge of certain software functions whichare needed to perform highly specialised tasks. E.g.knowledge about quality assurance to provide theproduction with the right CAx-quality data can also beregarded as specialist knowledge.The listing above already implies the responsibilityfor the different kinds of knowledge. (There is adifference between: Who is responsible-and-Who hasto impart the knowledge.) UniversitiesThe universities are in charge of the general CAx-knowledge. This includes technology and businessoperations as main topics:*The overall perspective on the CAx-technologyincluding history, trends, possibilities, unsolvedproblems and fundamentals like the mathematicsand basic IT-knowledge.*The standard industry processes with respect of CAx-technologyincluding an overview on product datamodel technique, PDM, data exchange*Principles of relations between companies: OEMs,suppliers and SW-vendors*The standard design methods and procedures (see. e.g.Refs. 5,6) in the view of CAx-technology*The general handling of modern CAx-tools includingan overview of the market and the fields of application*A training on at least one common CAx-tool, to getpractical experience in product design with CAx-technology. CompaniesThe companies are responsible for their employees,that they are able to be efficient in their work. Thisincludes all necessary CAx-knowledge, which is calledspecialised and specialists knowledge. The CAx-training task a company will delegate to subcontractor orinto special departments (see below). Of course someparts of specialists know-how remain, which will beimparted directly within the application departmentsduring the running job:*Special training with the CAx-tool, concerning thecommon practice in this particular department, used3rd-party-tools and special company conventions.*Training on the special procedures and structureswhich are related to this specific job. Training companies or training departmentsTraining enterprises or training departments in biggercompanies are responsible for the specialised knowledgewhich includes:*Training for a job (e.g. CAx-designer for engines)with the specific CAx-systems. This also includesteaching of the best practice for common tasks, knownproblems and their workarounds.*Training to manage CAx-data in PDM/PLM systems.Huge companies often have special PDM/PLMsystems, the use of them can also be taught bytrainers, not necessarily employees of the mother-company. These external trainers are specialised forone company.*Interoperability and CAx-data exchange Software vendorsThe Software vendors offer training as well, butoften this training is not well suitable for training ofapplication people in industry. This has severalreasons:*In SW-houses there is often a lack of expertise in theapplication with its processes, methods and resultingproblems of the product creation.*In most cases the clients of the SW-vendors belong toquite different industrial branches.*Software vendors are not i