Design and Development of an Injection Mold Tool for Top Cover Bearing used in Automobiles by IRJET Journal

Design and Development of an Injection Mold Tool for Top Cover Bearing used in Automobiles

Ravi Kumar P1 , Kuldeep Kora2

1M-Tech Tool Engineering Scholar, Government Tool Room and Training Centre (GTTC), Mysuru 2Tool Design Engineer, Government Tool Room and Training Centre (GTTC), Mysuru

Abstract - Injection Molding is a very old and advanced manufacturing technique in which heated molten polymer is forced into mold opening under huge pressure. The heated plastic in the mold then cools down, solidifies to form desired shaped part. Top cover bearing is a part used to accommodate in automobile suspension systems. Material selected is Nylon 6 with 30% glass filled (black). The grade of the material is SGR 30 and the shrinkage factor of 0.6%. The component and tool designs are done with the help of Unigraphics (NX 11.0). Mold flow analysis is carried out using the software Easy flow advance NX 11.0. Finally, manufacturing, tool trials and corrections were performed.

Keywords: Injection Molding, Top cover bearing, Nylon 6, Shrinkage factor, Easy flow advance

1. INTRODUCTION

One well-liked and effective method for making plastic objectsistheuseofinjectionmolding.Typically,thismethod usesmoltenpolymerthermoplasticsasthesubstrate.Thatis the order in which they originated and cooled. Infusion molding plastics are used in nearly every functional produced item in today's society, from food containers to vehicles.

Topcoverbearingisusedinthesuspensionassemblyofthe automobiles. Investigating the Nylon-6 substance that is usedinthepieceof equipmentisthefirststep.Theinitial stage involves a thorough analysis of the substance specs and part dimensions (from 3D CAD). Choice of separating lines,drawing,shrinkageexpense,optimalgateplacements, runnerlayout,extractionofcoresandcavities,ejectedunits, andventilationsystemsareallincludedindesign.

2. OBJECTIVES

 Studyofthecomponentanddesign

 ToolDesignCalculations

 Investigationofmoldflow

 Solidcomponentofthetool

3. METHODOLOGY

4. COMPONENT STUDY AND 3D MODELLING

Thepartiscalledatopcoverbearing.Nylon-6makesupthe componentsubstance,whichhas30%glasspackedinit.The part has a black color and a SGR 30 rating. The part has a volumeof298.35cm³.Thetotalmassofthecomponentsis 406.23 grams. The part has a density of 1.35 grams/cubic centimeter andanapproximate volume reduction of 0.6%. Themeltingpointis285°C.Partthatisproducedisutilizedin cars/automobiles.

-2:Topcoverbearing3Dmodel

Fig -1:FlowchartofMethodology

Fig

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 11 Issue: 09 | Sep 2024 www.irjet.net p-ISSN: 2395-0072

5. TOOL DESIGN CALCULATIONS

This section outlines a methodical approach to obtaining theoreticalvaluesforspecificmoldproperties.Pointingout that the real values is much greater and takes into safe consideration,becausethegainedpropertiesarenotdirectly usedinthemold.

5.1 Calculation of molding weight

Shot weight (Sw)

Weightofcomponent(w)=MaterialdensityxVolume

w=1.35x298.35

w=402.77g

Incorporatethemoldmassintotheformulaandmultiplyby themultiplicationfactor(M.F),therefore,

Shotweightofcomponent(Sw)=WeightofcomponentxM.F

Sw=402.77x1.05=422.90g

Sw = 423g

5.2 Clamping force/clamping tonnage

Clampingforce=ProjectedareawithfeedsystemxInjection pressure

Projectedareawithfeedsystemis256cm2 .

ForprocessingNylon6with30%glassfilledtoproducean engineering part, the injection pressure required is 1650 kg/cm2 .

Thecavitypressureiscalculatedtobe1/2oftheinjection pressurebecauseNylon6with30%glassfillhasgoodflow abilityandisalsotheleastviscousmaterial.

Cf=Projectedareawithfeedsystemx1/2Injectionpressure =256x[1/2x1650]=211200kgf

Cf = 220 T

5.3 Capacity to plasticize (Pc)

Shot Capacity

Shotcapacity=SweptvolumexMaterialdensityxConstant

Where, Constant = correction factor for percent volume expansion of the plastic at the molding temperature for Nylon=0.35(semi-crystallinematerials).

Thescrew-typeisnormallyratedintermsofsweptvolume oftheinjectioncylinder=900cm³.Densityofthematerialis 1.35g/cm³.

Shotcapacity(g)=900x1.35x0.35=425.25g

Shot capacity of the machine = 425 g

5.4 Calculation of number of cavities

Calculatingthequantityofcavitiesfrommachinecapacity

Ns = Shot capacity of the machine / Shot weight of the component

Shot/MachinecapacityofthemachineforNylon-630%glass filled is 425 grams. Shot weight of the component is 423 grams.

Ns=425/423=1.005

Ns=1Cavity

Depending on shot capacity, a single cavity mold can be accepted.

5.5 Design of feed system

Diameterofsprue=10mm

Diameterofrunner=6mm

DiameteroftheTunnelgate=1.547mm

No.ofgatesused=4numbers

5.6 Determination of working length of finger cam

L=[Ms/Sinθ]+[2c/Sin2θ]

Where,Ms=splitsmovementtoejectthecomponent positively=32.5mm

θ=angleoffingercam=25°

c=clearancebetweenholeandthefingercaminthe splits=0.5mm

L=[32.5/Sin25]+[(2x0.5)/Sin2(25)]

L = 78.2 mm

Fig -3:Partwithfeedsystem

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 11 Issue: 09 | Sep 2024 www.irjet.net p-ISSN: 2395-0072

5.7 Length of side core (Ls)

Lengthofsidecore=Fittinglength+Workinglength+radius offingercam

Where,

Fitting length = (Diameter of finger cam x 2) + Factor of

Safety=(22x2)+10=54mm

Working length = [Slider stroke (Undercut + 5mm)] / Sin (Fingercamangle)=[42+10]/Sin25=123.04mm

Radiusofthefingercam=11mm

Therefore,

Lengthofsidecore=54+123.04+11=188.04mm

Hencelengthofsidecore(Ls)is188.04mm

5.8 Injection time (Ti)

Theinjectiontimetakenafterthecalculationis6.25s(value fromtheanalysisreport).

5.9 Cooling calculations

ThesolidifyingtimetakenaftercalculationisTs=40s(value fromthemoldflowreport).

5.10 Cycle time estimation

InjectionTime,Ti=6.25s

SolidifyingTime,Ts=40s

Moldopeningandclosingtime,Toc=2Td=2x5=10s

Where,Td=machinecycletime=assumedas5s

EjectionTime(Te)=2sapproximately

MoldlubricationtimeTL =3+(ns+nc)+(nc-1)

Numberofsidecores(ns)=2

Numberofcavities(nc)=1

TL=3+(2+1)+(1-1)=6s

Therefore,totalcycletime=Ti+Ts+Toc+Te+TL =6.25+40+10+2+6=64.25s

Totalcycletime=65s

Fromtheabovecalculationsthecycletimeis65seconds.

5.11 Determination of number of shots/hr.

Numberofshot/hr.=Totaltime/Totalcycletime =3600/65 =55shots/hr.

Hence,numberofshots/hr.is55.

6. ANALYSIS OF MOULD

It focuses on the flow characteristics of plastics. After the holeisfilledbymoltenplastic,theflowcharacteristicsare measured.PlasterflowestimationisdoneinNXSimpleFill BasicandMoldedFlowConsultant.

TheapplicationMouldex3DcontrolsNXEasy-FillPlus.Early inthegoodsinnovationperiod,designersmaytestthemold abilityofplasticpiecedesignsthankstothisincludedmold simulatortool.Inordertooptimizegatenumber/locations, choosingmaterials,componentdesign,operationalcriteria, orproductchoice,programmersmayadditionallyperform adjustmentsinadvance.Autodesk'sMoldedFlowAdviseris asmall,inexpensivedevicethatsimulatesdesignthroughout elementmanufacture.Thankstotheelectronicsamplesthat are produced, time to market and costs can be drastically decreased.TheadvisermakesiteasiertoaddCADdatafrom severalwidelyusedprograms,suchasSolidWorks®,andit speedsupitemtraining.

6.1 Reports from the Flow Analysis

Fig -4:MeltFrontTime

Fig -5:GateContribution

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 11 Issue: 09 | Sep 2024 www.irjet.net p-ISSN: 2395-0072

The part with less weld marks and a workable design is depicted in the image. Raise the liquid warmth or the container'sheattopreventweldstreaks.Loadingtimeought tobeshortened.Increasetherateofinjection.

6.1.2 Air Trap

Fig -10:Airtrap

Thesiteswherewindtrapmayoccurareindicatedbytheair captureresult.Thepresenceofair-trapsisindicatedbythe component's blue color. Escapes should be arranged in a circular pattern to prevent air trapping. The baking time oughttobeincreased.Movetheentrywaytoanewlocation. Reduce the speed at which you inject. Modify the valves locationorsize.

7. TOOL DESIGN

Afillingmoldisadevicemadeupofmultiplecomponents thatareusedtomold&coolhotmaterialintoacertainpart configuration. The tool's components as they appear in belowfigure.

Fig -11:Explodedviewof2-platemold

Fig -6:Moldability

Fig -7:Pressure

Fig -8:Temperature

6.1.1 Weld line

Fig -9:Weldline

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 11 Issue: 09 | Sep 2024 www.irjet.net

8. MANUFACTURING & ASSEMBLY OF TOOL

8.1 Fabrication of tool

Partdesignswithanadequatedimensionalrangearecreated for everysingle elementafterthefinal layoutiscomplete. Uponreceiptofthedrawings,themakingdepartmentmust determine whether to buy or manufacture them. Conventionalpartssuchasbolts&nutsareobtainedfrom marketplaces, while pieces that cannot be constructed internally are contracted. Other components that can be manufacturedinternallyutilizingthe existingfacilitiesare retained. After deciding which pieces need to be made internally,themanufacturingbranchstartsdevelopment.

-14:Machiningoperations&machineuse

8.2 Assembly of the tool

Theconstructionworkperformedbythetoolmakerisquite skilled.Agoodtoolrequirestheabilityofthetoolmakerto maneuvereachpartintoitsdesignatedspotinaccordance with the layout. The two most crucial factors to take into account when assembling are attention and hygiene. The pieces will be destroyed if they are not handled carefully, whichwillresultinwastedtimeandincreasethepriceofthe mold.

9. TOOL TRIALS

Followingconstructionandassembly,thetoolverifiedthat theshapeandsizesofthecomponentweremanufacturedin accordancewiththecustomer'sspecifications.Try-outisthe process of subjecting a production tool to real-world operationalrequirementsonaninjectionmoldingmachine.

Themoldhasbeenclearedofoilanddirt.Oncethemold's halves are closed, the product flows by force via the equipment'snozzleandintothesupplyline.Thematerialis transportedtothemold'scavitiesby thefeedmechanism. Thesubstanceiskeptunderstressuntilthepartisdried.The partcanthenbeejectedafterthetoolhasbeenexposedand themechanismthatreleasesitassemblyisactivated.

The item is immediately examined after the test runs and thenforwardedtothemoldingqualitycontroldivisionfor theinitialtrialobservationreport,wheregradeassurance commentsareprovidedandthecomponentsisevaluatedin

Fig -12:3Disometricviewofmoldtool

Fig -13:Manufacturingprocessplanning

Fig

all parameters. All the components are submitted for assemblyandinspectionifeachsizeisacceptable.

For the first several shots, less force is used to inject the substance.Duetotherecentdie,itisessentialtocheckfor substanceleaksandensurethatboththecore&cavityare suitable for the hot operating circumstances. Both the engagementpressure&theappliedflowarebeingsteadily maintained.Onthefirstattempt,defectivecomponentsthat werenotfilledweremade.

9.1 Defects occurs in mold

It is frequently difficult to identify the root reason behind molding errors due to the multitude of elements that influence injection formed item manufacture. Multiple reasons can lead to a single error. The reasons may have startedwiththepropertiesofthestuff,thecircumstanceof theprocess,themoldingmachine,oranothermold.Before tryingtofixanyerrors,it'scrucialtothoroughlyunderstand thedifferentkindsoferrorsandtheirrootcausesandfixes forthem.

The component has the following defects that have been observed:

 Weldlines

 Air-traps&Airbubbles

 Flowlines

 Cracks

 Flash

 Ejectorpinmarks

Table -1: Inspectionreport

10. CONCLUSION

Inthiscovertwork,itisdescribedthelayoutofapolymer injection molding usedtocreatethetopbearingcover, an itemfoundincars Anexaminationoftheelementmaterial isconductedinordertoascertainitsphysical,chemical,and electrical characteristics as well as its mold ability. The machinethatismostsuitedtooperatethemoldprocessis selected through estimates. The NX Easy Fill Plus & Flow Advisorprogramwasusedtodothestudy.Beforetryingto fixatoolthatdoesn'tfunctionwellonthefirsttry,it'scrucial tothoroughlyunderstandthemanykindsoferrorsandthe rootcausefixesforthem.Then,thetoolisconstructedafter goingthroughthestagesofproduction.

9.2 Finished Part

Fig -15:Part’scoreside

Fig -16:Part’scavityside

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 11 Issue: 09 | Sep 2024 www.irjet.net p-ISSN: 2395-0072

11. SCOPE FOR FUTURE WORK

 If there are multiple kinds of bearing parts manufacturing The core & cavity frames can be changedtoreusethesamemoldbaseintheevent thatanotherpieceisdelivered.

 Theoutcomesofthemoldflowstudycanbeutilized toenhancethemolddesign.Furtherresearchcanbe donetooptimizethesettingsandboostthemold's productivity.

 FiniteElementAnalysisprogramcanbeutilizedto predicttoollongevityandperformstresstestand endurance analyses on the mold's component elements.

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