7. Calendering Process

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CORPORATE TRAINING AND PLANNING CALENDERING PROCESS

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How to make plastic sheets

Transcript of 7. Calendering Process

CORPORATE TRAINING AND PLANNINGCALENDERING PROCESSCORPORATE TRAINING AND PLANNINGCALENDERING PROCESSBASIC PRINCIPLECalendaring is the process of squeeing a plastic!elt"et#eent#oor!orecounter rotatingc$lindersorrollstofor!a continuous fil! and sheet% The art of for!ing a plastic sheet has "een adoptedfro!thetechniqueof!a&ing paper' !etal and ru""er in industriesCORPORATE TRAINING AND PLANNINGPlastic material andits CompoundTheP(Cresinisgenerall$processedin calendaringplant'anditneeds"lending' !i)ingandco!pounding"$additionof suita"le che!icals called as additi*es and fillersto!a&eco!pound"efore processing in the calendering plant%OtherthenP(CresinA+,'PE'PPand ,t$renearealsousedforcalendering process%CORPORATE TRAINING AND PLANNINGCalendering process with plant detailsTherollsareheatedeither"$stea!orhotoilandroll te!perature ranges fro! -./0 to -1/0C% 2lu)ed!aterialdeli*eredtothefirstcalendarnipis regulatedtofor!arolling"an&%Thesheetpassingthe firstnipfor!sanother"an&"et#eenthesecondand thirdrolls'atthefinalnip'thedesiredthic&nessis o"tainedfro!thes!allest"an&possi"leto!ini!ie stress in the sheet%CORPORATE TRAINING AND PLANNINGCORPORATE TRAINING AND PLANNINGTake off rollSheetCORPORATE TRAINING AND PLANNINGEmbossing and laminating To create leather li&e grain or other surface structure' the hotsheetco!ingfro!thestripperrollsispassed "et#eenasteelrollnipped"$aru""errollthatforces the P(C into the grain%Tola!inateanothersheetorafa"rictothecalendared sheet'it!a$"enippedagainstthesheetonthelast calendarrollorala!inatingstation!a$"einstalledin place of the e!"ossing rolls%CORPORATE TRAINING AND PLANNINGCalendering process with plant detailsAfterflu)ingandgelation'eitherat#oroll!illoran e)truderisusedtofor!strandsoran$accepta"le for!s% 3eltis!aintainedanddeli*eredtothecalenderat around -4/5-6/0C%Thecalenderrollsqueeesaplastic!eltintoaflat sheet%CORPORATE TRAINING AND PLANNINGCoolingand winding of the sheet Thesheetiscooled"$passingito*ercoolingrollsthenthrougha thic&ness gauge prior to "eing #ound5up% The sheet is then tri!!ed to required #idth and #ound on a tu"e or cut to length and stac&ed as sheets% The tri!!ed edges of the sheet can "e rec$cled%CORPORATE TRAINING AND PLANNINGPrecautions to e ta!en during processing Preparationofstoc&forcalendering'conditionsonthe calender'theta&eoff'thic&ness!easure!ents'and control to #ind up%Otherconsiderationsinclude#hethertheplasticis la!inated to a fa"ric on the calender%CORPORATE TRAINING AND PLANNING"#pes of calenders ,uperi!posed calenders 7I 8T$pe9Offset calenders 7L or In*erted L T$pe9: t$pe of CalendersTheIt!pe calender rolls has the ad*antage of ta&ing up a !ini!u! of floor space and offers the designer a !ore si!ple pro"le! for the strength of the side fra!esCORPORATE TRAINING AND PLANNING"#pes of calenders"# t!pe calender has the ad*antage that "ending of the rolls caused "$ pressure of !aterial in the nip has no effect on the succeeding nip and therefore tends to i!pro*e thic&ness accurac$% The in$erted L# offers a good co!pro!ise' since the first pair of horiontal rolls hold the input !aterial easil$ succeeding t#o nips can "e arranged to gi*e good controlCORPORATE TRAINING AND PLANNING5 T!peCORPORATE TRAINING AND PLANNINGCORPORATE TRAINING AND PLANNING ;igh pressure hot #ater 7;%P%;%