模具专业英语chapter5-11-21

ProfessionalEnglishondesignofplasticmouldChapter5Mouldtempreturecontrol2012-11.212Chapter5Mouldtempreturecontrol例句分析•Itisoftenfoundadvantageoustouseaslightlyhighertemperaturethanrequiredjusttofilltheimpression,asthistendstoimprovethesurfacefinishofthemoldingbyminimizingweldlines,flowmarksandotherblemishes.3Chapter5Mouldtempreturecontrol例句分析•Thereforetoachieveanevencoolingrateoverthemoldingsurfaceitisnecessarytolocatetheincomingcoolantfluidadjacentto‘hot’moldingsurfacesandtolocatethechannelscontaining‘heated’coolantfluidadjacentto‘cool’moldingsurfaces.4Chapter5Mouldtempreturecontrol课文详解•Onefundamentalprincipleofinjectionmoldingisthathotmaterialentersthemould,whereitcoolsrapidlytoatemperatureatwhichitsolidifiessufficientlytoretaintheshapeoftheimpression.5Chapter5Mouldtempreturecontrol课文详解•Thetemperatureofthemouldisthereforeimportantasitgovernsaportionoftheoverallmoldingcycle.6Chapter5Mouldtempreturecontrol课文详解•Whilethemeltflowsmorefreelyinahotmould,agreatercoolingperiodisrequiredbeforethesolidifiedmoldingcanbeejected.7Chapter5Mouldtempreturecontrol课文详解•Alternatively,whilethemeltsolidifiesquicklyinacoldmoulditmaynotreachtheextremitiesoftheimpression.8Chapter5Mouldtempreturecontrol课文详解•Acompromisebetweenthetwoextremesmustthereforebeacceptedtoobtaintheoptimummoldingcycle.9Chapter5Mouldtempreturecontrol课文详解•Theoperatingtemperatureforaparticularmouldwilldependonanumberoffactorswhichincludethefollowing:10Chapter5Mouldtempreturecontrol课文详解•typeandgradeofmaterialtobemolded;lengthofflowwithintheimpression;wallsectionofthemolding;lengthofthefeedsystem,etc.11Chapter5Mouldtempreturecontrol课文详解•Itisoftenfoundadvantageoustouseaslightlyhighertemperaturethanisrequiredjusttofilltheimpression,asthistendstoimprovethesurfacefinishofthemoldingbyminimizingweldlines,flowmarksandotherblemishes.12Chapter5Mouldtempreturecontrol课文详解•Tomaintaintherequiredtemperaturedifferentialbetweenthemouldandplasticmaterial,water(orotherfluid)iscirculatedthroughholesorchannelswithinthemould.13Chapter5Mouldtempreturecontrol课文详解•Theseholesorchannelsaretermedflow-waysorwater-waysandthecompletesystemofflowwaysistermedthecircuit.14Chapter5Mouldtempreturecontrol课文详解•Duringtheimpressionfillingstagethehottestmaterialwillbeinthevicinityoftheentrypoint,i.e.thegate,thecoolestmaterialwillbeatthepointfarthestfromtheentry.15Chapter5Mouldtempreturecontrol课文详解•Thetemperatureofthecoolantfluid,however,increasesasitpassesthroughthemould.16Chapter5Mouldtempreturecontrol课文详解•Thereforetoachieveanevencoolingrateoverthemoldingsurfaceitisnecessarytolocatetheincomingcoolantfluidadjacentto‘hot’moldingsurfacesandtolocatethechannelscontaining‘heated’coolantfluidadjacentto‘cool’moldingsurfaces.17Chapter5Mouldtempreturecontrol课文详解•However,aswillbeseenfromthefollowingdiscussion,itisnotalwayspracticabletoadopttheidealizedapproachandthedesignermustuseafairamountofcommonsensewhenlayingoutcoolantcircuitsifunnecessarilyexpensivemouldsaretobeavoided.18Chapter5Mouldtempreturecontrol课文详解•Unitsforthecirculationofwater(andotherfluids)arecommerciallyavailable.Theseunitsaresimplyconnectedtothemouldviaflexiblehoses,withtheseunitsthemould’stemperaturecanbemaintainedwithincloselimits.19Chapter5Mouldtempreturecontrol课文详解•Closetemperaturecontrolisnotpossibleusingthealternativesysteminwhichthemouldisconnectedtoacoldwatersupply.20Chapter5Mouldtempreturecontrol课文详解•Itisthemoulddesigner’sresponsibilitytoprovideanadequatecirculatingsystemwithinthemould.Ingeneral,thesimplestsystemsarethoseinwhichholesareboredlongitudinallythroughthemouldplates.21Chapter5Mouldtempreturecontrol课文详解•However,thisisnotnecessarilythemostefficientmethodforaparticularmould.22Chapter5Mouldtempreturecontrol课文详解•Whenusingdrillingsforthecirculationofthecoolant,however,thesemustnotbepositionedtooclosetotheimpression(saycloserthan16mm)asthisislikelytocauseamarkedtemperaturevariationacrosstheimpression,withresultantmoldingproblems.23Chapter5Mouldtempreturecontrol课文详解•Thelayoutofacircuitisoftencomplicatedbythefactthatflowwaysmustnotbedrilledtooclosetoanyotherholeinthesamemouldplate.24Chapter5Mouldtempreturecontrol课文详解•Itwillberecalledthatthemouldplatehasalargenumberofholesorrecesses,toaccommodateejectorpins,guidepillars,guidebushes,spruebush,inserts,etc.25Chapter5Mouldtempreturecontrol课文详解•Howcloseitissafetopositioninaflowwayadjacenttoanotherholedependstoalargeextentonthedepthoftheflowwaydrillingrequired.26Chapter5Mouldtempreturecontrol课文详解•Whendrillingdeepflowwaysthereisatendencyforthedrilltowanderoffitsprescribedcourse.27Chapter5Mouldtempreturecontrol课文详解•Arulewhichisoftenappliedisthatfordrillingsupto150mmdeeptheflowwayshouldnotbecloserthan3mmtoanyotherhole.Fordeeperflowwaysthisallowanceisincreasedto5mm.28Chapter5Mouldtempreturecontrol课文详解•Toobtainthebestpossiblepositionforacircuititisgoodpracticetolaythecircuitinattheearliestopportunityinthedesign.29Chapter5Mouldtempreturecontrol课文详解•Theothermoulditemssuchasejectorpins,guidebushes,etc.,canthenbepositionedaccordingly.