7ReasonstoReconsiderUltrasonicSealingforYourVFFSBaggingLineBillAurand,Sonics&Materials,Inc.

Inrecentyears,manycompanieshavebeguntoconsiderconvertingtheirVFFSbaggingmachinesfromheatsealingtoultrasonicsealingtechnology.Theideaofreducingfilmconsumptionbynarrowingthesealwidthisacommondrivertowardultrasonicsealing.Anotheristheunderstandingthatanoccasionallettuceleaforpieceofcheesethatgetscaughtinthesealareawillnolongerpresentaproblembecausetheultrasonicsystemwillsealrightthroughtheproduct.Whilethesearegoodreasonstoconsiderultrasonicsealing,amorethoroughevaluationrevealsevengreaterbenefits.Belowisalistofadvantagesthatshouldbeinvestigatedwhenconsideringtheswitchtoultrasonicsealingtechnology.1-ReducedfilmcostWithultrasonics,thesealthicknessistypicallyreducedto2mmorless.Inonelarge-scalestudy,crosssealthicknessreductionresultedinan11%filmsavingsaccordingtoalargeCPGinthesnackfoodmarket.Seeillustrationbelow(©EWI.Imageusedwithpermission)

• Inadditiontonarrowingtheseal,ultrasonictechnologycanprovideadditionalfilmsavingsby

allowingthesamevolumeofproducttobecontainedinasmallerpackage.Thesmallerbagismadepossiblebecauseheadspacecanbereducedwithoutconcernforproductinthesealarea.Theoverallbagsizecanpotentiallybereducedbyasmuchas20%,dependingupontheproductbeingpackaged.Insomecases,zeroheadspacepackagingispossible.

• Simpler,lesscostlyfilmstructurescanbeconsidered.Ultrasonicsealingcanbeusedwithoutasealantlayerinsomecases.Todate,evaluationofultrasonictechnologyhasprimarilybeendoneonfilmsdesignedforheatsealing.Whenfilmsuppliersbegindevelopingproductsspecificallyforultrasonictechnology,evengreatersavingswillberealized.

2-Lesswastedproduct

• Theabilitytosealthroughcontaminationmeanswasteisnolongergeneratedwheninternalproducthangsupinthesealarea.Notonlydoesthisenhancetheprocessatthebagger,itfurtherreduceswastedownstream.Faultysealscreatedwithheatsealingmaynotbediscovereduntiltheyhavedamageddozensofotherpackagesduringshipment.

• Feweroverallrejectsmeansmoreproductoutthedoor.Itisnotuncommonforultrasonicsealingtoseerejectratesaslowas1:100,000seals.Ofcoursethisvarieswithfilmtypeandproductbeingpackaged,butoncetheultrasonicprocessisoptimized,thereisnobetterwaytoguaranteehighqualityhermeticseals.

3-Enhancedthroughput

Ratherthansimplycomparingheatsealtimesversusultrasonicsealtimes,CPGsshouldconsidertotalproductivity.Sealtimealonedoesnotdictateoutput.Actualultrasonicsealtimesareusuallyverysimilartoheatsealingtimes.Theincreaseinproductivityisduetootherreasons.Alsofactorinthefollowing:• Higherthroughputduetoreducedconcernsoverproductinthesealarea.Becauseultrasonic

toolscansealthroughproductcontamination,lesstimeisrequiredtowaitforproducttofallclearofthesealjaws.Thereforethemachinecansafelybesettorunatafasterrate.

• Increasedmachinespeedsduetotheeliminationofhottackconcerns.Whenbaggingheavierproducts,residualheatinthesealscancausepackagefailuresunlessthemachineissloweddowntoallowthesealstocool.Ultrasonicsealingdoesnothavehottackissuesbecausethetoolsremaincoolandlessoverallheathasbeenappliedtothefilm.Ultrasonicsealsexhibitfullstrengthalmostimmediately.Seeillustrationbelow.

• Productivityisfurtherincreasedwithultrasonictechnologybecausetheprocessdoesnot

requireanywarmuptime.ThefirstbagofthedayfromanultrasonicVFFSsystemisperfect.Typicalheatsealjawscanrequireupto15minutesofwarmuptime.15minutes@80bagsperminute=1200additionalbagsproducedusingultrasonicseachtimethemachineisstartedup.

4-Improvedproductquality.

Whilethisshouldbeaprimarydriver,strangelytheproductqualityenhancementsarerarelyfullyevaluatedbyCPGs.Considerthefollowing:

• Ultrasonicsealsonaverageare‘tighter’andmorehermeticthanheatseals.Asaresultofbettersealquality,thereductioninOxygentransmissionratewithultrasonicsealingisdramatic.Nitrogen

Heatsealing Ultrasonicsealing

flushismaintainedformanymonthsversusafewweekswithheatsealing.Thisresultsinfresherproductswithmuchlongershelflife.Seeillustrationbelow(©EWI.Imageusedwithpermission)

• Further,whenultrasonictechnologyisusedonVFFSbaggers,hermeticsealsarecreatedevenwhenthefilmiscreased,makingtheentireprocessmuchmoreforgivingandproductive.

5-Enhancedsafetyandmaintenance

• BasedonanextendedstudydoneatalargeCPGfacility,maintenancepersonnelwerestronglyinfavorofultrasonicsealingoverheatbecausetherearenoissueswithburnswhenworkingwithultrasonicsystems.Oncepowereddown,itiscompletelysafetohandletheultrasonictools.

• Inaddition,heatsealingtoolscanbetimeconsumingtocleanduetotheinternalproductandfilmbecomingbakedonovertime.Becauseultrasonictoolsstaycool,theyaremucheasiertoclean.

6-Reducedenergyconsumption

• Heatsealingdrawssignificantelectricalcurrentduringtheentireshifttomaintainthesetsealtemperaturewithinthejaws.UltrasonictechnologyisanOn/Offprocess,meaningthesystemdrawsessentiallynoelectricityexceptduringtheactualprogrammedsealtime.Withsealtimesasfastas100milliseconds,itiseasytoseehowultrasonictechnologycanprovideenergysavings.

7–Ultrasonicsealingisan‘intelligent’process

• Intoday’smanufacturingworld,blindprocessescannolongerbetolerated.Withheatsealingtechnology,operatorshavenowayofknowingwhetheranyspecificbagwassealedproperlyorevenunderthesameconditionsasthenext.Ultrasonicsealingprovidesintelligencetotheprocessbyallowingparameterssuchassealtime,peakpowerdrawandtheactualenergydeliveredintoeachcrosssealtobemonitored.Thisdatacanthenbeusedtotracktheprocessorevendivertsuspectbagsfortesting.

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Wehopethelistabovewillgiveyouabetterunderstandingofwhatultrasonicsealingtechnologycanbringtoyourpackagingoperation.Clearly,ultrasonicscanofferfarmoretothebaggingprocessthanmerelynarrowingthesealthicknessorcuttingthroughanoccasionallettuceleaf.Unfortunately,manyoftheotherbenefitscanbedifficulttoquantifyuntiltheprocesshasbeeninuseforaperiodoftime.Withoutfullknowledgeofalloftheadvantagesofferedbyultrasonicsealing,manyCPGsmaketheirdecisionbasedononlythetangiblematerial.Thisfact,combinedwiththehistoricallyhighcostandcomplexityofintegratingultrasonicsexplainswhyultrasonicsealingisn’tcurrentlybeingusedbyeveryone.Thegoodnewsisthatimprovementsinultrasonicequipmenttechnologyaswellasrecentadvancesinapplicationsprovideevenmorereasonstoreinvestigatethisbeneficialprocess.

• Thecostofultrasonicequipmentisnotashighasyoumayhavebeenleadtobelieve.Completecomponentsystemscannowbedeliveredatafractionofthecostofwhatwastypicaljustafewyearsago.Infact,eventurnkeyultrasonicconversionsforusedbaggingequipmentarenowacosteffectiveoption.

• Beyondbeingmoreaffordable,itshouldbenotedthatthecomplexityofcurrentultrasonicsealingsystemsisnotwhatitwasinthepast.Today’smodernsingleconverterdriveultrasonicsystemsarefarsimpler,moreuserfriendlyandmorerobustthanoutdated‘twinstack’designs.

• Inaddition,recentbreakthroughsinsealbeadgeometrynowenableultrasonicsealingtobeusedingussetapplications.Strong,hermeticultrasonicsealsacrossthetransitionfrom4layersoffilmto2layersarenowpossible.ThisopensupthepossibilityforultrasonicstobeappliedinapplicationssuchasgussetbagcrosssealsandsidesealsforstanduppouchesproducedonVFFSmachinery.

Withsomuchtobegainedbyusingultrasonicsealing,andthetechnologicaladvancementsintoday’smodernultrasonicpackagingsystems,therearecompellingreasonstogiveultrasonicsealingasecond(andcloser)look.AbouttheauthorBillAurandisthePackagingTechnologyManagerforSonics&Materials,Inc.Hebeganhiscareerinultrasonicsin1985asanUltrasonicWeldingApplicationsEngineerimmediatelyfollowinghiscollegeeducation.SincethenBillhasheldvariousmanagementlevelpositionswithinseveralAmericanandEuropeanultrasonicequipmentmanufacturers.Throughouthiscareer,Mr.Aurandhasbeenresponsibleforprovidingeducationalseminarsonultrasonictechnologybothdomesticallyandinternationallyforinternalemployees,customers,UniversitystudentsandlocalSPEandSPIchapters.Bill’smarketemphasisshiftedfromrigidplasticpartassemblytoflexiblepackagingin2010asnewinnovationsinultrasonictechnologyallowedittobesuccessfullyappliedinapplicationsthathadpreviouslybeenavoided.In2013,BillwasaguestspeakeronRecentAdvancementsinUltrasonicFilmSealingattheANTECconventioninCincinnati,OH.BillwasalsoaguestpresenteronUnderstandingUltrasonicFilmSealing,ItsBenefitsandLimitationsattheGlobalPouchForumWest,2014.

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