1、Int J Adv Manuf Technol(2001)17:453461 2001 Springer-Verlag London LimitedThree-Dimensional Kernel Development for Injection MouldDesignT.L.Neo and K.S.LeeDepartment of Mechanical and Production Engineering,National University of Singapore,SingaporeToday,many software“plug-ins”have been developed on
2、high-level 3D modelling platforms to facilitate processes suchas FEM analysis,CAM,injection mould design,simulationand visualisation.Such an arrangement is advantageous inmany ways.However,it is not without shortcomings.Ideally,these“plug-ins”could also be developed using low-level 3Dkernels for hig
3、her flexibility and better portability.This paperexamines the various issues and methodologies related to thedevelopment of such 3D-based applications.The emphasis isplaced on the software aspect.First,a methodology for thedevelopment of 3D-based applications is proposed.The ideais then implemented
4、by developing an injection mould designapplication using a low-level 3D kernel called Parasolid.Basedon design concepts used in an established mould design appli-cation,IMOLD,the development of a mould base designmodule is illustrated.An object-oriented programming langu-age has been chosen for the
5、development of the software ona Windows NT platform.Keywords:3D kernel;Computer-aided design(CAD);Injec-tion mould design;Parasolid1.IntroductionThree-dimensional CAD systems have increasingly been usedto speed up the product realisation process.One of the firststeps involved in the automation of th
6、e product design processis the creation of the component parts in a 3D modellingapplication.The 3D model,upon creation,is called the digitalmaster copy.This 3D digital model forms the key to a widespectrum of process automation.Creating the 3D digital model of component parts is onlythe very first s
7、tep.There are several other secondary tasks thatmust to be done before the part can be manufactured.Suchtasks include finite-element analysis,jigs and fixtures design,injection mould design,computer-aided manufacturing,simul-Correspondence and offprint requests to:K.-S.Lee,Department ofMechanical an
8、d Production Engineering,National University of Singa-pore,119260 Singapore.E-mail:mpeleeksKnus.edu.sgation,and visualisation.Today,many application Plug-ins havebeen developed on high-level 3D modelling platforms to facili-tate these secondary tasks.The 3D-modelling platform providesthe plug-in sof
9、tware with a library of functions as well as anestablished user interface and style of programming.As aresult,the development times for these plug-ins are signifi-cantly reduced.Such an arrangement is advantageous in many ways.How-ever,it has its shortcomings,especially in the long run.Inorder to de
10、velop a plug-in for established software,the devel-opers must adhere to the many constraints imposed.There isa need to be consistent with the style of the parent software.The developers must be able to achieve any functionality theyneed with only the set of library functions provided.Mostend-users n
11、eed both the parent software and the plug-in.Inmany cases,however,they may be more interested in usingonly the plug-in software.An example of such a situation isin injection mould design.These users,however,must purchasethe entire software package which includes many features andfunctions that they
12、do not need.Such a large program is oftenvery demanding on the hardware,which also means higher cost.The plug-in software is also very dependent on developments inthe parent software.Whenever a new version is updated forthe parent software,the plug-in developers have to follow-upon the changes.These
13、 shortcomings may not exist if theseapplications were developed on a low-level platform.Ideally,these plug-ins could be developed using low-level 3D kernelsfor higher flexibility and better portability.In many instances,such a move is both feasible and advantageous.Traditionally,injection mould desi
14、gn is carried out directlyon a CAD system.The entire injection mould,consisting ofperhaps hundreds of components,is modelled and assembledon CAD systems such as AutoCAD,Pro/Engineer,and Uni-graphics.As the injection mould design process is recursive,it is very time-consuming to re-model and re-assem
15、ble thedesign.In this aspect,3D CAD systems such as Pro/Engineerand Unigraphics,which are feature-based,have a significantadvantage over 2D CAD systems such as AutoCAD.To furtherspeed up the injection mould design process,plug-ins weredeveloped on these 3D systems to automate certain stages ofthe de
16、sign process.Examples of such add-on applicationsinclude IMOLD(Intelligent Mold Design and Assembly Sys-454T.L.Neo and K.S.Leetem,developed at the National University of Singapore,basedon Unigraphics),Expert Mold Designer(based on CADKEY)and Moldmaker(based on EUCLID).As each is based on aspecific CAD system,there is no plug compatibility.In 1994,Mok and Cheung 1 presented work on the devel-opment of an injection mould design application based onUnigraphics.In 1997,Shah 2 proposed a 3-tier archi
