汽车附件调角器低档SUV滑轨I支架冲压模具设计【含16张CAD图纸+PDF图】
收藏
资源目录
压缩包内文档预览：(预览前20页/共38页)
编号：117449271
类型：共享资源
大小：2.55MB
格式：ZIP
上传时间：2021-03-12
上传人：好资料QQ****51605
认证信息
个人认证
孙**（实名认证）
江苏
IP属地：江苏
45
积分
- 关 键 词：
-
汽车附件
调角器
低档
SUV
滑轨
支架
冲压
模具设计
16
CAD
图纸
PDF
- 资源描述：
-
喜欢这套资料就充值下载吧。。。资源目录里展示的都可在线预览哦。。。下载后都有，，请放心下载，，文件全都包含在内，，【有疑问咨询QQ:1064457796 或 1304139763】
==================================喜欢这套资料就充值下载吧。。。资源目录里展示的都可在线预览哦。。。下载后都有，，请放心下载，，文件全都包含在内，，【有疑问咨询QQ:1064457796 或 1304139763】
==================================
- 内容简介：
-
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) 14391450/locate/cad*Corresponding 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 independent enough to makepeople aware of known software problems and usefulC.W. Dankwort et al. / Computer-Aided Design 36 (2004) 143914501443workarounds or to propose 3rd party solutions.*The training material of SW-vendors is mostlyIT-oriented and not well suitable for engineers.The training job of software vendors can be summarisedto train the trainers, which should include:*New and extended functionalities of new softwareversions.*General strategies and limitations of a given software*System interoperability, interfaces for data access andprogramming7. Training methodsIndependent from the training contents, there are severaltraining methods which differ in intensity and costs. Thesetraining methods can be combined in an effective way. Computer based TrainingThe cheapest way of CAx-training is the so calledComputer Based Training (CBT). Some CAx-systemvendors offer special software for studying the CAx-system in an autodidactic way. But also enterprisesspecialised on CBT offer their solutions. Most of theseCBT-programmes just show the handling and thefunctions of the program. Often there is a lack inteaching autonomous, independent work. Strategies tosolve design problems can not be standardised. Further-more this training method gives only little feedbackabout the success of the training. For example the studentor engineer will not be informed whether his/her trainingpart is right or wrong and why. Due to these deficienciesin the beginning the computer based training is not wildlyspread.But the development of the CBT technique is inprogress, more and more systems are able to learn bythemselves, which means, that the experiences a (pilot-)user made, can be captured and will be available forfuture training. Systems, which can be customised to theneeds of a special company are already available. Practical course (Face to face)A better, but more expensive way of CAx-Educationis a practical course with instructor guidance. Mainadvantage is the direct feedback from the CAx trainer.Another advantage is the possibility to get explanations,if there are questions, unsolved design problems orcurious behaviour of the CAx-system. A disadvantage is,that after the course is finished the trainer often is notavailable any longer. Follow-on coachingFollow-on coaching is a way to solve the problemdescribed above. If companies have an internal educationdepartment or a permanent external training staffin-housetheguidedtrainingcanbecombinedeasily with intensive onsite follow-on coaching.After the CAx-training is performed for and inside aspecial department, to meet the needs of the department,the trainer stays to provide further assistance. In-house HotlineMany bigger companies operate in-house Hotlines,where users can ask for support on specific problems.This is especially helpful, if an engineer has difficultieswith seldom used functionalities.When looking at the costs of the different trainingmethods it is inevitable to regard the overall costs, which arenot only influenced by the costs of trainers, trainingequipment or necessary hardware to do training. The mostimportant costs are due to the loss of capacity and efficiencyof the co-workers during training and in the run-up periodbefore getting full job performance. These costs can bebetween 2/3 and 3/4 of the overall education costs.Therefore when looking for an adequate training methodthe total costs have to be regarded. Very often it is far moreeconomical to send an engineer to an expensive trainingthan to leave him with computer based training withthe result of inefficient working over long term. (cf. alsochapter 9.2)8. The CAx-education in industryA typical CAx-education of a new employee in a biggercompany is shown in Fig. 4. It is based on guided training(eventually mixed with CBT), follow-on coaching andassistance.CAx-Education in industry depends on the size of thecompany. (This paper mainly uses information fromautomotive industry.) Generally it can be said, that thebigger or the more specialised a company the more tailoredCAx-training is. The OEMs in the automotive industry havemany users and very different applications, thus the CAx-training is organized in a modular system. Training byinternal and external trainers in a central educationdepartment is combined with inside-training in the variousFig. 4. A typical CAx-education and the efficiency of a new employee.C.W. Dankwort et al. / Computer-Aided Design 36 (2004) 143914501444engineering departments. CBT completes this concept. Foran efficient training the trainers have to have specialistknowledge of the job they are training people for. This leadsto job rotation, where e.g. very good CAx-engineers becomeCAx-trainers to train the next generation of engineers.8.1. Job rotationIn some automotive companies an optimisation loopbetween product engineering, CAx-education and CAx-application support was introduced (see Fig. 5).Here an organised job rotation is the base of deepunderstanding as well as up-to-date know-how of thepersons working in these three departments. The infor-mation flow is carried by the people involved: From Product Engineering to CAx-Education: Product-and application know-how, design procedures, workflowinformation (medium term this change is related with anadvancement) From CAx-Education to CAx-Support: Requirements onnew functionalities, on improvements; information aboutproblems and errors in functionalities; feedback aboutthe usability of applications From CAx-Support to Product Engineering: Backgroundof problems in functionalities; limitations based onprinciples of CAx-technology and/or on SW-bugs;complexity of SW operation. From CAx-Education to Product Engineering: In-depthknowledge about CAx-functionalities, hidden functionalalternatives, improvement of design procedures (nor-mally this change is combined with a coordinatingposition) FromCAx-supporttoCAx-Education:Know-howabout system-internal limitations (e.g. caused by thesystem architecture); functional by-passes.But the most important effect on efficiency is thepersonal relation between the persons in the variousdepartments. This helps to cope with difficulties duringthe product development process in a trouble-free, informalway. In a modern company job rotation of persons betweenany departments is a usual means in human resourcesdevelopment. In this case the know-how transfer betweendepartments is the most important advantage.8.2. Efforts for and within CAx-educationIn the automotive industry the costs and efforts for thesoftware itself and its maintenance are not the main part ofthe CAx-costs. A big amount is caused by the CAx-education. To estimate these costs various factors have to beconsidered: Direct costs. Capacity of the trainer, computer, licenses,rooms, Capacity for support during training on thejob Indirect costs. Time off of the trained person, decrease ofefficiency while training on the job. The over-all economic balance. CAx training has tobring a profit to the company. Thus the loss of labourtime and efficiency, summed up over all the trainingsperiods, has to be compensated by the increased jobperformance after successful training.These effects and costs differ for the different kind ofCAx-education: Basic and advanced CAx-training Specialised courses Refresher training and training for changes of systemsreleases Training new system versions Training of managementA typical engineering department in automotive industrywith about 300 CAx-engineers needs about 11.5 man-years for training and support per year. The averagebounded engineering capacity is about 35% of the totalcapacity. That means another 915 man-years per year.This sums up to a total of about 1016 man-years peryear. This loss of capacity has to be regained by the higherefficiency of the better educated engineers or by theadvantages of a new or improved CAx-system.Of high uncertainty are the training and support effortsduring the changes of the system versions. For the ongoingchange from CATIA V4 to CATIA V5 in the automotiveindustry no figures regarding the efforts have beenpublished, but the costs on training and support can beregarded as a big part of the total costs of the change.9. Teaching horizon at universitiesAs already mentioned above, it is in the responsibility ofthe universities to impart the general CAx-knowledge to thestudents. The curriculum for engineers is normallylimited in the number of hours for lectures and training.Fig. 5. Optimisation loop.C.W. Dankwort et al. / Computer-Aided Design 36 (2004) 143914501445Therefore not all subjects can be taught, which might be ofinterest for later industrial work.That does not mean that students can not get profoundCAx-knowledge during their studies beyond the formalcurriculum. They can e.g. improve their CAx-know-how invarious fields of interest by internships, voluntarily specialcourses, or work at university in research groups. What kindof knowledge and in which depth a student gains duringhis/her studies is in his/her responsibility. In most caseshe/she has the opportunity to get voluntarily an extendedCAx-education, including specialist knowledge in certainareas. This specialist knowledge may get vital for him/her,when applying for a job in industry.During his/her studies the student should get goodfundamentals for his/her future work. Since engineering hassuch a wide range, it is obvious, that the learning processwill not end at the university. Life long learning is theslogan. This holds especially for modern product develop-ment, which is based on classical and modern designmethods as well as on fast changing CAx-technologies.Therefore the student has to be prepared for his/her futurejob, but the required specialist know-how he/she has to getin the job or parallel to it and has to update it as long ashe/she is in professional life.9.1. CAx fundamentals in design and workflowThe education for engineers should include bothengineering techniques (like machine elements etc. ) andCAx-aspects. The various lecturers have to cooperate and tocoordinate the content of their lectures.A holistic view on the todays industrial developmentand manufacturing process of products is the base ofunderstanding the single steps like detail engineeringdesign. Knowledge about the industrial workflow combinedwith the related information flow and management isnecessary to understand the needs and problems in industrialprocesses. Therefore, the students have to learn not onlyabout product data models but also about CAx-dataexchange with actual standards like STEP. Detailededucation in PDM/PLM normally exceed the frame of thelimited curriculum, but special education should be offeredfor interested students, if the university has enoughcapacities.9.2. Design knowledgeDesign knowledge is not well defined, although it is ofhighest importance Various aspects may be considered fromthe viewpoint of education: Scientific design methodology. Theoretical approaches assubjects of research. These areas are out of scope ofCAx-education. Generic design methods and procedures developedto support real engineering work like concepts ofPahlandBeitz 5 or the directives of the VDI 6. CAx-design methods and procedures developed out ofthe capabilities of CAx-systems. Individual or team-internal experiences for design andfulfillingspecialengineeringtasks.Thisfieldisclosely related to the product or product part underconsideration.Especially the last three points are some kind of aknowledge base of an engineer. It should include alsoknowledge about the over-all product development process,and basics such as engineering components, primaryfunctional principles, and recommended standard parts aswell. Here the know-how return flow from industry is ofimportance.This knowledge the students will learn through variousstandard lectures at the university about different subjects.In the context of an engineers education concerning CAxmethods and procedures three different levels should bediscussed in examples: Parametric modelling 7, Feature based design 8are nowadays standard for modern CAx-systems andtherefore also in CAx-education (although there aredifferent understandings of features in CAx-systems,the authors follow the definition of FEMEX 9) Associative design is closely connected to the specialproduct structures. Industrial companies often protecttheir know-how in this field against competitors. Engineering in Reverse 10 is an holistic approach,which even some industrial researcher do not considerto be of importance in the near future although insome companies prototypes operate already. Suchapproaches go beyond standard CAx-education.All these design methods and strategies are mainlyproduct driven although there are also roots in CAx-technology. From the viewpoint of the authors no side-neither the product development nor the CAx-technologycan claim to be the originator of new design methods. It isalways a cooperation.Today Concurrent engineering and Simultaneousengineering. are of central importance in industry. CAxmethods supporting these strategies, like Cooperativeengineering or CAx-conferencing can not be trained inpraxis at most universities. But the students have to learn atleast theoretically about them.DesignmethodsandproceduresarenotchangingasfastasCAx-technologies. Nevertheless, it is an important topic inthe curriculum of engineer students. These fundamentals aretaught at the universities often by lectures teachingengineering sciences. But the aspects of CAx-technologyhave to be included. Design knowledge can not be taughtcompletely at universities, because in industrial life eachcompany has its special necessities due to the kind of itsproduct and has developed its own development strategy.C.W. Dankwort et al. / Computer-Aided Design 36 (2004) 143914501446Inindustrythedesignmethodsandproceduresareneverusedas formal as taught at universities. It is not subject of thispaper to compare these approaches in theory and practice.Typical concepts are described by Pahl & Beitz 5 or in theVDI 2221 6. Both defined very formal design steps, but theindustry has to follow internal and external constraints, e.g.:In automotive industry the concept phase, in which usuallythe functional principles are obtained, is restricted by theconstraints caused by the development platforms. The aimof these development platforms is to increase the number ofidentical parts within different vehicles. The knowledgeabout these circumstances has to be gained on the job.9.3. Practical training with CAx-systemsPractical training and work with a system by the studenthim/her self in front of a workstation is the standard for anyCAx-education. It is not necessary to go into details, but afew aspects should be mentioned: The student should be taughtwhenever possibleinmore than one of the standard systems. From industrial point of view it is an advantage for thecompany if the student is trained at the university withthe system, he/she will use in his/her job in the company. It is important that the student can work already at theuniversity with a sequence of CAx-systems, e.g.:*CAD ! CNC: producing a model of the part he/shedesigned*CAD ! FEA: performing some calculations with thepart he/she designed*CAS ! CAD: Designing the shape of a product andlearning about the difficulties to fulfil engineeringrequirements with it. Of importance are practical experiences in data exchangeand also in PDM/PLM applications. Due to the limits incurricula they are often not taught.9.4. Mathematical foundationsIn the history of CAD there are various internalmathematical representations of geometry, elementarysolid geometric elements and free form shapes: Concerning solids two representations are of interest: B-Reps and CSG (primarily only with primitive solids,nowadays also with B-Reps). Concerning free form shapes a few descriptions areimportant, all based on polynomial representation likeBe zier-, natural-polynomials, B-Splines and NURBS. Additional surface descriptions by point clouds or/and byvery dense facets are used for visualisation or CNC-milling.All CAx-system kernels use some of these represen-tations for basic CAx-functionalities. The necessary internalmathematical algorithms using these representations aremostly protected intellectual property and are normally notof interest for the CAx-user. But the users have to beinterested in the quality of the results.As already mentioned nowadays additional to theclassical CAx-functionalities (like e.g. surfacesurfaceintersection), parametric geometry, variational design andassociative relations between various geometries are state ofthe art. But in what detail does mathematics have to betaught in CAx-education? From our point of view generallyany person related toCAx shouldbe taughtsome knowledgeof mathematical fundamentals: An overview of the various mathematical representationsincluding their advantages and disadvantages, possibi-lities, the degree of freedom in design, but not theformulas themselves. An overview of algorithms of functionalities anddesign procedures. Of interest are the logic, thephilosophy, the possible problems, the advantagesanddisadvantagesandthequalityoftheusednumerical methods. Again formulas of the mathemat-icalalgorithmsthemselvesarenotofparticularinterest.The aim is to make students or future engineers able tojudge how reliable a result calculated by a CAx-system isand which specific application problem might be caused bythe mathematical representation. Of course the mathemat-ical knowledge usually taught at the universities is notsufficient for all CAx-related jobs. People like CAx-software developers or engineers for CAx-applicationtools need much more in-depth knowledge. But where dothese people get this knowledge from? This in-depthmathematical knowledge has to be imparted by the industryor software house. There are various alternatives again: Within the company there are already experiencedexperts, who did research on this subject in the past,e.g. at universities. These specialists could teach theyounger colleagues. The company could employ specialists as temporaryteachers from universities or research institutes. The company could send the selected employees tospecial seminars or internships at a university orresearch institute.Thus, the teaching of particular in-depth mathematicalknowledge again is a task of the universities. But it is notpart of the standard CAx-education curriculum.9.5. IT-knowledgeStandard IT-knowledge has to be trained at universities.This knowledge should be sufficient for the standardCAx-user or CAx-manager. Nowadays anybody, not onlyC.W. Dankwort et al. / Computer-Aided Design 36 (2004) 143914501447CAx-concerned people, should be familiar with thistechnique. Further in-depth IT-training within CAx-edu-cation at universities is not really reasonable due to someproblems: The modern IT-world is changing very fast. Specialistknowledge, which would be trained at universities,would be out-of-date even before the student wouldhave left the university. In industry there are many different platforms hard- andsoftware configurations, each of them requiring differentknowledge. On which platform, on which hard- andsoftware should the students be trained?It is the job of the universities to give an overview of theup-to-date hard-and software configurations and to makestudents aware of opportunities, which are connected tothem. An example might be the potentialities and problemsof the Application Programming Interfaces (APIs), whichare usually parts of the standard CAx-tools: APIs on one hand offer users the opportunity to extendtheir in-house systems to solutions of specific problems.Via API most of the standard CAx-functionalities can beused within a 3rd-party-SW-module written for a specificproblem for a special customer. On the other hand API-programming is a very difficulttask and very often the API is not documented verywell. Additionally the API might be changed by asoftware vendor during a release change, with theeffect that 3rd-party programs may not run anymore.All this very special CAx-related IT-know-how can onlybe learnt in high level seminars or courses, performed fromthe specialists of SW suppliers or well experienced 3rd-party vendors. This is out of the scope of universityteaching.A special field belonging to IT is Computer graphics.Some fundamentals of this subject should to taught in theframe of CAX fundamentals.9.6. Selection of CAx-systems for CAx-educationat universitiesThe decision which CAx-Systems should be used foreducation at universities is not as complex as the selectionof a CAx-system for a company. From our point of viewin the beginning of the CAx-education a standardmidrange system should be used. The system vendorshould give any student the opportunity to install aversion at his/her home PC for a very low price. In themain study period the students should be able to handleone of the popular high-end systems. Additionally itwould be an advantage, if they could have access to othersystems of the market, if they want to. Some aspectsshould be discussed: Modern CAx-systems are very complex and even inindustry no one really knows and uses all of thedelivered functionalities. Depending on the branch andthe project about 1520% of its capabilities are used.For standard CAx-education at universities there is nochance trying to teach the studentsthe wholefunctionality of one or more systems. But they shouldget a more or less broad overview, so that thestudents can understand the philosophy, which isbehind the systems. For a special application fieldhe/she may go more in-depth. The common CAx-systems such as CATIA-V5, Uni-graphics and Pro/Engineer are not very different in thelook and feel. Thus for CAx-education one systems isas good as the other. Thus, being taught the use of onesystem, the student should be able to get used to anyother system very quickly. Usually the time, which is planned in the curriculum forCAx-education is too short to guarantee a broad CAx-education. Until there will be a shift from classicalengineering to modern CAx-integrated design, thestudents have to enlarge their knowledge voluntarily. Oftenindustrialcompaniesaskforengineersbeingtaughtattheuniversitythesamesystemasusedbythiscompany.From our view point a student should be taught anothersystemattheuniversity:lateroninhis/herjobthemindofthe engineer will be more flexible and not limited by thecapabilities of the only system.To sum up, one or two systems for the basic andadvanced education is enough, but it is vital that studentscan enlarge their knowledge by having access to othersystems, if they want to. Any standard CAx-system can beused in CAx-education, the decision depends on theprovided support from the vendors and expertise on thedifferent systems at the university. The price, the neededcapacities for maintenance and-last not least-the availabilityof the system for the student at home are further aspects.10. ConclusionThe modern product development gets more and morecomplex and is a part of the product lifecycle. CAx-technologies are completely integrated. Therefore, productdevelopment can not be seen on its own, as CAx and CAx-education can not be considered stand-alone. HistoricallyCAD was in the focus. Nowadays a network of various CAxfields is supporting quite different tasks and occupationalprofiles in product development and manufacturing.Therefore CAx education has to be considered in thispaper, this may be summed up in some statements: CAD is only a part of CAx. CAx engineering isan integrated part of modern product developmentand manufacturing.C.W. Dankwort et al. / Computer-Aided Design 36 (2004) 143914501448 There is not any precise job profile for engineers inindustry. Mechanical engineering is connected to manydifferent technical/scientific disciplines. Most pro-fessions are related to CAx in some kind. To think about one broad CAx-education is fiction. CAxeducation always has to be tailored to a specific group ofpersons and/or jobs. CAx education has two bases: Universities and freeindustrial enterprises.University aspects: Universities have to teach the CAx-basics and designmethodology to all students. It is in the responsi-bilities of the students to enlarge their knowledge incertain areas. Universities have the duty to offeropportunities to the students to get specialist knowl-edge in a broad range of subjects.Industrial aspects: The human potential is the most important field ofinvestments, the education of the employees is a key for along term companies success. Companies have to take care of specialised CAx-education for their employees. They can not expect toget completely trained employees for their specifictasks in a special system.Human aspects: New CAx-oriented design methodologies like associat-ive modelling will create new job profiles. Fluctuation of people within short time is standardnowadays: moving from operational activities intocoordination/management positions. Or changing thebranch: moving from product related departments toCAx-/IT-technology related fields. Individuals become more and more responsible for theirown CAx-education. Students will need to find their ownfield of interest, where they need to gain specialistknowledge in order to be competitive on the job market. The effort for CAx-education and the related expenseshave one reason in the complexity of the tool-theCAx-systems. In the future we expect, that psycho-logical aspects will come to the foreground, thehuman way of thinking and communicating will bethe guideline for new system development. Someattempts were already done by using terms of thelanguage to control and modifying shape design 11.Although we are convinced of the importance of modernIT-based techniques, we should not forget the way, how wehad come to the present level of technology: In analogy tothe evolution theory of Charles Darwin we may remember,that in the evolution of any individual there are manycomponents/aspects of the evolution of the history beforethis person. We should not completely forget the classicalmethods and experiences of engineering work in the lastcentury, which may be a part of the education of a modernIT-orien
- 温馨提示:
1: 本站所有资源如无特殊说明，都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等，如果需要附件，请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸，网页内容里面会有图纸预览，若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间，仅对用户上传内容的表现方式做保护处理，对用户上传分享的文档内容本身不做任何修改或编辑，并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容，请与我们联系，我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
人人文库网所有资源均是用户自行上传分享，仅供网友学习交流，未经上传用户书面授权，请勿作他用。
川公网安备: 51019002004831号