Integration of CAD/CAE System for Casting Process Design

TSINGHUA SCIENCE AND TECHNOLOCYISSN 1007-0214 19/19 pp117- 120Volume 8，Number 1, February 2003Integration of CAD/CAE System for Casting Process Design'zHoU Jian(周舰), JING Tao (荆涛)""Department of Mechanical Engineering, Tsinghua University, Beijing 10084, ChinaAbstract; Concurrent engineering is needed to modernize the foundry industry and to reduce the scrap fromcastings and thus increase the economic profit. This paper presents an integrated 3-D CAD/CAE system for afoundry using concurrent engineering which considers casting structure, casting type, and manufacturingproperties in the CAD module to design the pouring system, the riser, the chill core and so on. A visualized .solid model is developed for the casting component with the model design enhanced by CAE analysis. Heattranster and fluid flow simulation are used to analyze the initial design. The whole product development processis analyzed using concurrent engineering methods. The aplication shows that the integrated system canimprove the fficiency of the design and manufacturing process of die casting.Key words: concurrent engineering; computer alded design (CAD)computer aided engineering (CAE);casting processconsidered and reviewedsimultaneouslyIntroductionthroughout all phases of the development cycle.Casting Irocess design plays a veryConcurrent engineering also provides earlyin the quality of casting components.recognition for any changes related to testing ，Conventionally, castingprocess design wasquality or maintenance. Concurrent engineeringperformedby foundry engineers who usedtheirtechnology integrates expertise from variousexperience to design the process. As a result,engineering disciplines during the design phase.development of a casting component takes a longWhen a casting process design is verified, it istime with much un-productive initial work. Toalready a testable and serviceable high qualitybecome more competitive in the challenging worlddesign. The whole focus of concurrent engineeringmarketplace, foundry engineers are trying tois on a“right first time" process, rather than onreduce the time and cost of development and tothe“redo-until-right”process that is so common inimprove the casting qualtyl1r8.the casting industry.In recent years, the concept of concurrentThis paper discusses an integrated 3-D CAD/engineering has been proposed as an efficientCAE system using concurrent engineering tmethod for designing and optimizing the castingachieve high quality components at low cost and inprocessmeetincreasingly stringenta shorter time. Engineers produce the first trialrequirements. In concurrent engineering， thecomponent using the CAD module (developed onproduct, the process and all life cycle issues arethe SolidEdge platform) for the casting process.After the mould and the casting have beendesigned, the initial and steady-state mouldReceived: 2001 12- 04; revised: 2002- 09-13* Supported by the National Natural Science Foundationtemperatures, the gate size and location and thefilling time can be optimized by using the CAEof China (No. 5990470)★* To whom correspondence should be addressed.module, which can numerically predict theE-mail : todd@sun. midwest. com. cn;occurrence of defects by analyzing the transportTel; 86- 10-62785854pher中国煤化工process."TYHCNMHG118Tsinghua Science and Technology, February 2003, 8(1); 117-1201 Integration of CAD/CAE Systemoptimization;●Pattern plate design.for the Casting ProcessThe integrated CAD/CAE system can be usedThe integrated 3-D CAD/CAE system for theby design engineers to simultaneously check thecasting process is shown schematically in Fig. 1.processandtsimplementation.TheThe approach requires the engineers to first modelmanufacturability, testability, and maintainabilitythe components in SolidEdge. The data files arecan be evaluated, so that the concurrentthen transferred to_ the CAD/CAE modules tengineering approach may foresee productionanalyze the casting process in the following ways;problems before putting the design into●Computer aided design of the casting process;production.●Computer aided engineering analysis andCAD/CAM for modeing'es_C asting processDisplay the resuts ofmanufactureoptimized?numnerical simulationNoCAD system forcastingCAE systmNumericalMoid flingsimulation ofStandard for process Paramcters ofsolifcationsimulationRiser designparametersheat analysisSolidifcationRunner designData for designingResults ofChill core designPattern plate design ....Results of designinganalysisDatabase for designcasting process量Gridding of casting3-D modeling ofModeling withthe parameters of8wt Paesscomponents and othercasting componentcasting process .materialsFig. 1 Schematic view of the CAD/CAE system2 Solid Model of the Componentto the heat transfer analysis pre-processor. Thesystem described in this paper was used to designDesignthe riser system for a casting component.3-D CAD software has emerged as a superb tool2. 1 Risering design and modulus analysisfor casting component design, especially whenthere is added value in linking the geometry toThe design is based on a modulus which is theprogress that will analyze the structure, thecasting volume divided by its cooling surface area,thermal hydraulics, and the mold flling. The 3-Dthe metallurgical quality of the iron, and the moldmodel of a casting mold is essential for usingrigidity. Figure 2 shows the family of appliedexisting technologies to analyze the castingrisering methods.process. A 3-D model of a casting mold needs theThe primary objective of the modulus analysis isproper pattern, the riser and the gating systemto determine the feeding units for a casting whichwhich are based on the geometry of the finaldetermines the number and the locations of theproduct to a large extent.risers and to calculate the proper size of each riserThis CAD system automatically designs theand riser neck. The pattern was split intopattern，riser system， and runner system tosegments with the system calculating the transfergenerate a complete 3-D geometric model of the,二ce the key modulimold using 3-D models of the pattern, the risers ,hay中国煤化工i of the riser andand the gating system which can be directly linked:YHC N M H Gshown in Fig.3.ZHOu Jian (周规) et al; Integration of CAD/CAE System for Casting Process Design119The runner system, the chill core, and otherMoldparameters can also be automatically designedusing the casting process CAD system as shown inWeak moldStrong moldFig.5.Modulus moldModulus0.4 cm<0.4 cm<2.0 cm>2.0 cm .RiserlessDirecly appliedcontrol riserdesignconrounaerFig. 2 Applied risering methodsFig. 5 Design of runner system3 Casting Process OptimizationAfter the modeling geometry has been accepted bythe designers，the reliability of the casting processmust then be verified. A 3-D computer code wasdeveloped to model the fluid flow and heat transferFig. 3 Modulus analysisduring mold flling and solidification of the castingusing the SOLA-VOF algorithm-ir8B.2. 2 Design of riser and riser neckThe program solves the modified Navier- Stokesequations and continuity equations to simulate theThe dimensions of the riser and riser neck areflow of the liquid metal, the location and the shapecalculated using the moduli of the riser and thof the free surface， and thetemperatureriser neck. In principle, the riser and riser neckdistribution，as well as the shrinkage cavities/must allow liquid iron to flow as long as there isporosity. The pressure field and speed field aresignificant liquid flow from ansegment.calculated iteratively. The analysis improves theTherefore, the riser modulus and the riser neckfilling process simulation and reduces themodulus must equal the transfer modulus.computing time. The simulation results areThe system can automatically choose thedisplayed graphically on the computer screen.matched riser system using the key moduli, andThe component model can be meshed into a datathe risers are moved and rotated interactively tofile, which is used to simulate the solidification andthe best locations and orientations with respect tomold filling processes. The results in Fig. 6 showthe pattern. The design of the riser system layouta typical temperature distribution and the predicteduses the graphical interface shown in Fig. 4.shrinkage cavity for a fact.4 Conclusions1) A 3-D CAD/CAE system was developed forSpherialcasting processes using the concepts of concurrentriserengineering.2) The data for the mould geometry and theprocess parameters, such as the riser system, thesand core, and the pouring system, can be directlyinput to the solid model , which can then be meshedin the pre-processing part of the CAE module.3) The casting process can then be optimized byhe CAE module to predict the occurrence ofFig. 4 Design of riser and riser neckdefect中国煤化工he transportequatiYHCNMHG120Tsinghua Science and Technology, February 2003, 8(1); 117- 120..FIg.6 CAE analysis resultsReferences[1] Gao J X, Manson B M, Kyratsis P. Implementation[5] Liu BC, Qiu w, Shen H F. Study and pplication ofof concurrent engineering in the suppliers to the .mold fllig sinulation of shaped castings. Journalautomotive_ industry. Journal of Materialsof Material Science Technology， 1997， 13(1);Processing Technology, 2000, 11(107); 201 - 208107-112.[2] HuBH, TongK K, NiuXP, et al. Design and6] JiaL R, XiongS M, Liu B C. Study on numericaloptimization of runner and gating systems for the diesimulation of moldinand heat transfer in diecasting of twalledcasting process. Journal of Material Scienceparts through numerical simulation. Journal ofTechnology, 2000, 16(3); 269 - 272.Materials Processing Techmology, 2000， 9(105):[7] Sirell B, Holliday M, Campbell J. Benchnark test.128 - 133.Modeling of Casting， Welding and Advanced[3] Sheu J J. A three-dimensional CAD/CAM/CAESolidification Processes VII, 1995; 915 - 933integration system of sculpture surface die for hollow8] Kim W S, Kim D s, Kuznetsov A V. Simulation ofcold extrusion. International Journal of MachinecoupleturbulentTools and Manufacture, 1999, 39(1); 33-53.wedge-shaped pool of a twin-roll strip casting[4] Nichols B D, Hirt C w，Hotchkis R s.process. International Journal of Heat and MassSOLA-VOF: A solution algorithm for transient fluidTransfer, 2000, 43(1): 3811 - 3822.flow with multiple free boundaries. Los AlamosScientific Laboratory Report, LA-8355, 1980中国煤化工MYHCNMHG