3DP砂型施涂烘干變形分析及預防

3DP砂型施涂烘干變形分析及預防1.IntroductionWiththedevelopmentofadditivemanufacturingtechnology,3Dprintinghasbeenwidelyusedinvariousfields,includingcastingindustry.3Dprintingsandmoldshavetheadvantagesofhighefficiency,personalization,andhighprecision,whichcangreatlyimprovethequalityofcastings.However,duetothedifferenceinmaterialpropertiesandprocessingmethodsbetweentraditionalsandmoldsand3Dprintedsandmolds,thedeformationproblemoftenoccursduringthecoatinganddryingprocess,whichseriouslyaffectstheaccuracyandqualityofthefinalproduct.Inthispaper,wewilldiscussthecausesofdeformation,analyzethedeformationmechanism,andproposeeffectivepreventionandcontrolmeasures.2.CausesofDeformationThedeformationproblemof3Dprintedsandmoldsduringthecoatinganddryingprocessismainlycausedbythedifferenceinmaterialpropertiesandprocessingmethods.Comparedwithtraditionalsandmolds,3Dprintedsandmoldshavethecharacteristicsoflowerdensity,lowermechanicalstrength,andhigherporosity.Meanwhile,the3Dprintingprocessalsohastheproblemofirregularlydistributedporesandresidualstress.Whenthesandmoldiscoatedanddried,themoistureinthecoatingwillpenetrateintothesandmoldandcauseunevenstressdistribution,whichwillproducedeformation.Thefollowingfactorscanalsoaffectthedeformationofsandmolds:-Thethicknessofthecoatinglayer:Thethickerthecoatinglayer,thehigherthewatercontentandthelongerthedryingtime.Ifthethicknessofthecoatinglayerexceedstheappropriaterange,deformationismorelikelytooccur.-Thedryingtemperatureandtime:Ifthedryingtemperatureistoohighorthedryingtimeistoolong,themoistureinsidethesandmoldwillevaporatetooquickly,causingunevenstressdistributionanddeformation.-Thetypeofcoating:Thedifferenttypesofcoatingshavedifferentwaterabsorptionanddryingproperties,whichcanaffectthedeformationofthesandmold.3.DeformationMechanism3.1ShrinkageDeformationDuringthecoatinganddryingprocess,themoistureinthecoatingwillpenetrateintothesandmold,causingthesandmoldtoexpand.Afteracertainperiodoftime,themoisturewillgraduallyevaporate,andthesandmoldwillshrink.Iftheshrinkagerateisnotuniform,itwillcausedeformation.3.2Non-uniformStressDeformationWhenthesandmoldiscoated,differentpartsofthemoldwillabsorbdifferentamountsofwaterduetotheunevencoatingthicknessandpermeability,resultinginnon-uniformstress.Whendrying,themoisturewillevaporatefromthesurfacelayerfirst,andthengraduallypenetrateintotheinnerlayer,causingthestressdistributiontochange.Thisprocesswillproducedeformation.3.3ResidualStressDeformationDuetothe3Dprintingprocess,thesandmoldmayhaveresidualstress,whichwillbereleasedduringthecoatinganddryingprocess,causingdeformation.4.PreventionandControlMeasures4.1OptimizationoftheDesignInthedesignstage,thefollowingmeasurescanbetakentopreventorreducethedeformationofsandmolds:-Adjustthethicknessofthecoatinglayertoanappropriaterange.-Optimizethedesignofthesandmoldtoreducetheinfluenceofunevenstressdistribution.-Reducethenumberofsupportstructuresinthe3Dprintingprocesstoreduceresidualstress.4.2ControloftheCoatingProcessDuringthecoatingprocess,thefollowingmeasurescanbetakentopreventorreducethedeformationofsandmolds:-Controlthethicknessofthecoatinglayer,andensurethatthethicknessiswithintheappropriaterange.-Adjustthecoatingprocessparameters,suchasthehumidityandtemperature,toensureuniformdrying.-Usecoatingswithbetterdryingpropertiestoreducetheabsorptionofmoisture.4.3ControloftheDryingProcessDuringthedryingprocess,thefollowingmeasurescanbetakentopreventorreducethedeformationofsandmolds:-Controlthedryingtemperatureandtime,andensurethatthetemperatureandtimearewithintheappropriaterange.-Useappropriatedryingmethods,suchasnaturaldryingorforceddrying,toreducedeformation.-Controlthehumidityandventilationduringthedryingprocesstoensureuniformdrying.5.ConclusionDeformationisacommonprobleminthe3Dprintingsandmoldcoatinganddryingprocess.Thedeformationmechanismismainlycausedbyshrinkagedeformation,non-uniformstressdeformation,andresidualstressdeformation.Byoptimizingthedesign,controllingthecoatingprocess,andcontrollingthedryingprocess,thedeformationproblemcanbeeffectivelypreventedorreduced.However,differentcastingprocesseshavedifferentrequ