Johdanto
Intheearlynineteenthcentury,theleadtypeproductiontechnologywasintroducedtoChinafromtheWest.Inthesubsequentdevelopment,theproductionofcoppermoldshaschangedwitheachpassingday,andtheleadtypecastinghasalsoimproved.Anddevelopfrommanualoperationtomechanization.Atfirst,hand-pattedtypecastingfurnaceswereusedforcastingtype.Later,foot-operatedtypecastingfurnacesandhand-operatedtypecastingfurnaceswereused,andthespeedincreasedto700to800charactersperhour.IntheearlyyearsoftheRepublicofChina,theCommercialPressintroducedthe"ThomsonAutomaticCastingFurnace".Notonlyhasmorethan15,000charactersbeencastdaily,butthecastedcharacterscanbeuseddirectlywithoutprocessing.Sofar,thecastingtechnologyhasreachedmaturity.
Raakamateriaalit
Lyijysininen,hopeavalkoinen raskasmetalli.Se on myrkyllinen ja on venyvä metalliryhmä.Sulamispiste on327,502°C,kiehumispiste on1740°C,tiheys on11,3437g/cm^3,kovuus 1,5,rakenne on pehmeä.
Leadisoneoftheearliestmetalsusedbyhumans.In3000BC,humansalreadysmeltedleadfromore.Thecontentofleadintheearth'scrustis0.0016%,andthemainoreisgalena.Thereare4stableisotopesofleadinnature:lead204,206,207,208,andmorethan20radioactiveisotopes.
Metalleadisaffectedbyoxygen,waterandcarbondioxideintheair,anditssurfacewillquicklyoxidizetoformaprotectivefilm;underheating,leadcanquicklycombinewithoxygen,sulfur,andhalogen;leadandcoldhydrochloricacid,Coldsulfuricacidhasalmostnoeffectandcanreactwithhotorconcentratedhydrochloricacidandsulfuricacid;leadreactswithdilutenitricacid,butdoesnotreactwithconcentratednitricacid;leadcanslowlydissolveinstrongalkalinesolutions.
Leadismainlyusedtomakeleadstoragebatteries;leadalloyscanbeusedforleadcastingandsoldering;leadisalsousedtomakeprotectiveequipmentforradioactiveradiationandX-rays;leadanditscompoundsaremoretoxictothehumanbody.Andcanaccumulateinthehumanbody.Leadisusedasabuildingmaterial,usedinleadacetatebatteries,usedasbulletsandshells,solder,trophies,andsomealloysalsocontainlead.
Valaistusprofiili
Thelightingprofileisanindispensablelightingpropduringtheshootingprocess(especiallyindoorshooting).
Thisitemiscomposedofmanysmallsquares,andthesizecanbechangedaccordingtothesituation.Itcanmakethestronglightbecomesoftlight(withoutobviouscontour)afterbeingreflected,andithasnoeffectontheactorsandthelens.
Kopiointiversio
Aprintingplatemadeofpaper-castingcliche,usuallycalleda"copyversion".Theproductionprocessofthecopyplateistofirstarrangethemovabletypeplateexactlyasrequiredbytheleadtypeprintingplate,andthenusethemovabletypeplateasthemastertopressitintoanengravedtypecalledmudtypeandpapertypewithmudorspecialthickpaper,andthenusethemudTypeorpapertypecaststhecliche,andfinallyusesthecliche(fullpage)asaprintingplatemountingmachineforprinting.Theinventionandapplicationofthisprocesstechnologymarkedthedevelopmentofmodernletterpressprintingtoanewstage.
PapertypewasinventedbytheFrenchmanXieLuoin1829.By1871,AmericanB.B.Blackwellinventedtheuseofthinclicheplates,whichwereprintedonawoodenbackground.Theinventionandapplicationofpapertypemadetheletterpressprintingtechnologymature.Atthattime,asetofpapermoldscouldbecastmorethantentimes.Inthisway,aftertheleadtypeplateisarranged,onceitistypedintoapapertype,theplatecanbedisassembledtoreturnthetype,andthepapertypeisretainedforlateruse.Thepapertypeisnotonlyconvenientforstorage,butalsobecauseofitslightness,itcanbetransportedtoremoteplacesandprintedinmanyplaces.Ithascreatedfavorableconditionsfortheprintinganddistributionofbooksandperiodicals,especiallynewspapers.
Valuprosessi
Thecastingprocessisamethodofmassproductionofjewelrywithacastingmachine.Thismethodhastheadvantagesofimprovingworkefficiencyandreducingcost.Theprocessingprocedureisasfollows:
Therubbermoldismadeaccordingtothejewelrydesignsample;therubbermoldisusedtomakeawaxmoldbywaxinjection;thewaxmoldisplantedintoawaxtree;thecylinderwiththewaxtreeispouredintoplastertomakePutthegypsummoldintotheovenfordrying,andheatituntilthegypsummoldisdewaxed;pourthemoltengoldintothegypsummold;cleanandremovethegypsum,thenperformpolishingandinlayingprocedures.
Johtavat vaarat
Krooninen toksisuus
Long-termexposuretoleadanditscompoundscancauseheartpalpitations,excitement,andincreasedbloodredbloodcells.Afterleadinvadedthenervoussystem,insomnia,dreaminess,memoryloss,fatigue,andthendevelopedintomania,blindness,confusion,coma,andfinallydiedduetocerebrovascularhypoxia.Thebloodleadlevelisoftenhigherthan2.16micromol/Lbeforeclinicalsymptomsappear.Therefore,althoughthebloodleadlevelinmanychildrenishigh,thereisnospecialdiscomfort.Mildintellectualorbehavioralchangesarealsodifficulttobeaffectedbytheparents.Orthedoctorfoundout.Thisiswhytheleadpoisoningofchildreniscalled"hiddenkiller"abroad.
Karsinogeeninen
Animalexperimentsonleadinorganiccompoundshaveshownthattheymaycausecancer.Accordingtoliteraturerecords,leadisachronicandcumulativepoison,anddifferentindividualshaveverydifferentsensitivities.Forhumans,leadisapotentialurinarysystemcarcinogen.
Teratogenicity:Therearenotenoughanimalteststoprovideevidencethatleadanditscompoundsareteratogenic.
Mutation:Feedingmicewith1%leadacetatefeedincreasesthenumberofchromosomalfissure-fractureaberrationsinleukocyteculture.Thesechangesinvolveasinglechromosome,indicatingthatDNAreplicationisdamaged.
Levyjen valmistusprosessi
Usingmovabletypeastheoriginalplateandcopyingitintoastereotypecannotonlyimprovetheprintingenduranceoftheprintingplate,butalsocanbeusedforprintingindifferentplacesoronmultipleprintingpresses.
Typografiaa kutsutaan myös paperityypiksi ja levyjen valmistusprosessiksi:
Alkuperäinen→ Paperinvalmistus→ Valutypografia→ Revisio→ Pinnoitus
Paperinvalmistustyyppi
Papertypeistocoverspecialpapertypepaperonmovabletypeorcopper-zincplate,applypressuretomakeatemplateforcastingleadplate.Thepapermoldcanbecastintoaflatandarc-shapedleadalloyprintforprintingonaflatbedmachineorarotarymachine.Thepapertypeiseasytosendtootherplacesforcastingandprinting,anditcanbestoredforalongtimeforreprinting.
Therearetwocommonlyusedmethodsforpapermaking,oneiswetmakingandtheotherisdrypressing.
(1)Thewetprocessistoplacetheoriginalplateintheironframeontheirontable,configureproperironbarstofastenit,brushawaythedust,andplacethepaper-shapedmaterialontheoriginalplateformolding.Whenmolding,coverapieceofdampclothonthepapermaterial,andreciprocatesmoothlyonthesurfaceofthedampclothwithaspecialbrush.Afterlaying,usecardboardtoflattentheblankpartofthepapertype,andthencoveritwithadampcloth.Afterthepapertypemeetsthequalityrequirements,itisputintotheflatteningmachinetogetherwiththeironframetoheatandbake,andfinallyitiscutandarrangedbeforeuse.
Thewetprocesswasoriginallyamanualtappingmethod,butnowitisamechanicaltappingmethod.Thepapertypemadebythewetmethodhasclearstrokesanddeephandwriting,whichisverysmallfromtheoriginalversion,buttheprocessiscomplicatedandtheproductionefficiencyislow.
(2)Drypressingisamethodofmechanicallypressingpaper.Dividedintocoldpressingmethodandpressingmethod.Thepapertypemadebythecoldpressingmethodneedstobeputinadryingroomfordryingtreatment.Thehotpressingmethodonlyheatsthepressingplateoftheneedlepressingmachineto100-120℃,andthepapertypecanbeobtainedundertheactionofpressure.
Päälevyn valu
Ontheplatecastingmachine,thepapertypeisusedasthetemplatetocasttheleadplate.Theplatecastingmachineisdividedintotwotypes:aflatplatecastingmachineandaroundplatecastingmachine.Theleadplatecastbythelithographicplatecastingmachineisusedforprintingbytheplatformmachine.Theroundplatecastingmachinecaststheleadplateintoanarcforprintingontherotarypress.
Retusointi
Thebackofthecastleadshouldbeflattenedorsmoothed,andtrimmedanddrilledshouldbecarriedout.
Galvanointi
Platingironorchromiummetalonthesurfaceoftheleadplatebyelectroplatingcanincreasetheprintingenduranceoftheprintingplate.Theiron-platedclichéhasaprintingenduranceofabout100,000impressions,andthechrome-platedclichéhasaprintingenduranceofabout500,000impressions.