Injection Molding-Injection MoldingProcess Descriptionver. 1ME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 20091Overview• Equipment• ProcessME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 20092EquipmentEquipmentClMldBlClampMoldHopperBarrelME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 20093EquipmentEquipmentME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 20094KrausMaffei at Ford4000 tonnesKrausMaffei at Ford -4000 tonnes5ME 6222: Manufacturing Processes and Systems Prof. J.S. Colton © GIT 2009Machine schematicME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 20096MoldME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 20097MoldMoldME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 20098Modular moldsModular moldsME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 20099Mold schematicME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200910Moldspruerunnercavitygatesprue nozzlepsidefrontejectionpinME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200911pinProcessME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200912ProcessProcess•Pellets placed in hopperPellets placed in hopper• Pellets fall into barrel through throatPllt kdt f lidbd•Pellets packed to form solid bed– air forced out through hopper• Pellets melted by mechanical shear between barrel and screwME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200913ProcessProcess•Melted plastic forms shot in front of•Melted plastic forms shot in front of screwbk lti–screw moves back as plastic moves forward (reciprocating screw)ME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200914Process• Screw moves forward to inject plastic jpinto mold cavityP t l d lidifi•Part cools and solidifies– next shot is madeME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200915ProcessProcess•Mold opens•Mold opens• Ejection pins move forward to eject part• Mold closes•Process starts again•Process starts againME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200916Solid bedSolid bed•Pellets crushed together•Pellets crushed together• Air ejectedME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200917Melting zoneMelting zone•Solid bed melted by mechanical shear•Solid bed melted by mechanical shearbarrelbarrelscrew flightsolid bedsecondarymixing flowscrew flightME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200918Homogenization zoneHomogenization zone• Melted polymer is homogenized thermally and color-wise.yME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200919Injection pressureInjection pressure• Typically 15,000 psi•Ranges from 3 000 to 40 000 psiRanges from 3,000 to 40,000 psi• Hydraulic pressure is about 10x lessME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200920Process timeClose moldInjectionOpen and eject partjp153335Part coolingPack and hold15ME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200921Pressure historyyMold closed timeCycle time50jectionCoolingMold closed time2st closingInjectionPackze offPart ej25FasGate freez33 3515500Time (s)ME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200922Time (s)Temperature historyTemperature historyCooling200jectionpart100st closingnjectionPackze offPart ejpgateFasIGate freez33 3515500Time (s)ME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200923Time (s)Gates and freezeoffGates and freeze-offFilling &PackingCoolingME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 200924ME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT
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