umjovo ukubumba inqubo izici ezithonya

Kwe umjovo inqubo yokubumba kwepulasitiki, thermoplastics, ngenxa yokushintsha kwevolumu okubangelwa i-crystallization, ukucindezeleka kwangaphakathi okuqinile, ingcindezi enkulu eyinsalela eqandisiwe engxenyeni yepulasitiki, ukuma kwamangqamuzana aqinile nezinye izici, kanjalo uma kuqhathaniswa ipulasitiki ye-thermoset, izinga lokuncipha likhulu. Izinga lokuncipha libanzi futhi ukuqondiswa kuyabonakala. Ngaphezu kwalokho, ukuncipha ngemva kokubunjwa, Ukwelashwa kwe-annealing noma ukuswakama ngokuvamile kukhulu kunaleyo yamapulasitiki e-thermosetting.

Lapho ingxenye yepulasitiki ibunjwa, into encibilikisiwe ithinta ingaphezulu lembobo futhi ungqimba lwangaphandle lupholiswa ngokushesha ukuze lwenze igobolondo eliqinile eliqinile.. Ngenxa yokungabibikho kwe-thermal conductivity yepulasitiki, ungqimba lwangaphakathi lwengxenye yepulasitiki lupholiswa kancane ukuze lwenze ungqimba oluqinile olunokuminyana okukhulu nokuncipha okukhulu.. Ngakho-ke, ubukhulu bodonga, ukupholisa kancane, futhi ukujiya kongqimba olunomthamo omkhulu kuzoncipha kakhulu. Ngaphezu kwalokho, ubukhona noma ukungabikho kokufakwayo kanye nesakhiwo kanye nenani lokufakwa kuthinta ngqo isiqondiso sokugeleza kwezinto, ukusatshalaliswa kokuminyana kanye nokumelana nokuncipha. Ngakho-ke, izici zezingxenye zepulasitiki zinomthelela omkhulu ekunciphiseni nasekuqondiseni.

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Izinto ezifana nefomu, ubungako, kanye nokusatshalaliswa kwe-feed inlet kuthinta ngqo isiqondiso sokugeleza kwezinto ezibonakalayo, ukusatshalaliswa kokuminyana, ukugcinwa kwengcindezi nokuncipha komphumela kanye nesikhathi sokubumba. Izimbobo zokuphakelayo eziqondile nezimbobo zokuphakelayo ezinezigaba ezinkulu (ikakhulukazi iziphambano eziminyene) abe nokushwabana okuncane kodwa ukuqondisa okukhulu, kanye nezimbobo zokuphakelayo ezimfushane ezinobubanzi obufushane nobude zinokuqondiswa okuncane. Lezo eziseduze nendawo yokuphakelayo noma ezihambisana nendawo yokugeleza kwezinto zizoncipha kakhulu.

Izimo zokubumba: izinga lokushisa eliphezulu lesikhunta, ukupholisa kancane kwempahla encibilikisiwe, ukuminyana okuphezulu kanye nokuncipha okukhulu, ikakhulukazi izinto crystalline, ngenxa ye-crystallinity ephezulu kanye nezinguquko ezinkulu zevolumu, ngakho ukuncipha kukhulu. Ukusatshalaliswa kwezinga lokushisa kwesikhunta nakho kuhlobene nokupholisa kwangaphakathi nangaphandle kanye nokufana kokuqina kwengxenye yepulasitiki, okuthinta ngokuqondile ubukhulu kanye nesiqondiso sokushwabana kwengxenye ngayinye. Ngaphezu kwalokho, ukubamba ingcindezi nesikhathi nakho kunomthelela omkhulu ekufinyezweni, futhi ukufinyela kuncane kodwa ukuqondiswa kukhulu lapho ingcindezi iphezulu futhi isikhathi siside.

Umfutho womjovo uphezulu, melt viscosity umehluko mncane, ukucindezeleka kwe-interlayer shear kuncane, futhi i-elastic rebound ngemuva kokudilizwa inkulu, ngakho-ke ukuncipha kungancishiswa ngenani elifanele. Izinga lokushisa elibonakalayo liphezulu, ukushwabana kukhulu, kodwa isiqondiso sincane. Ngakho-ke, ukulungisa i izinga lokushisa lesikhunta, ingcindezi, isivinini somjovo kanye nesikhathi sokupholisa ngesikhathi sokubunjwa kungashintsha ngokufanelekile ukushwabana kwengxenye yepulasitiki.

Lapho uklama isikhunta, ngokusho kohlu lokuncipha kwamapulasitiki ahlukahlukene, ubukhulu bodonga kanye nokuma kwengxenye yepulasitiki, ubukhulu nokusabalalisa kwefomu lokungena, izinga lokuncipha kwengxenye ngayinye yengxenye yepulasitiki linqunywa ngokusho kokuhlangenwe nakho, bese kubalwa ubukhulu bomgodi. Ngezingxenye zepulasitiki ezinembile kakhulu nalapho kunzima ukubamba izinga lokuncipha, izindlela ezilandelayo kufanele zisetshenziselwe ukuklama isikhunta:

①Isikhunta sesilingo sinquma ifomu, usayizi nezimo zokubumba zesistimu yokugenca.

②Izingxenye zepulasitiki ezizocutshungulwa zizocutshungulwa ukuze kunqunywe ukushintsha kosayizi (isilinganiso kufanele sibe 24 amahora ngemva kokudilizwa.

③ Lungisa isikhunta ngokuya ngokuncipha kwangempela.

④ Zama kabusha isikhunta futhi uguqule ngokufanelekile izimo zenqubo ukuze uguqule kancane inani lokushwabana ukuze lihlangabezane nezidingo zengxenye yepulasitiki.

I-fluidity ye-thermoplastics ingahlaziywa kusukela ochungechungeni lwezinkomba ezifana nesisindo samangqamuzana., ncibilikisa index, Ubude bokugeleza kwe-Archimedes, i-viscosity ebonakalayo kanye nesilinganiso sokugeleza (inqubo ubude / ingxenye yepulasitiki ukujiya odongeni).

Isisindo samangqamuzana amancane, ububanzi besisindo samangqamuzana, ukungajwayelekile kwesakhiwo samangqamuzana, high melt index, ubude bokugeleza okuvunguzayo, i-viscosity ephansi ebonakalayo, isilinganiso sokugeleza okuphezulu, fluidity enhle, amapulasitiki anegama elifanayo lomkhiqizo kufanele ahlole imiyalelo yawo ukuze anqume ukuthi uketshezi lwawo luyasebenza Ekubumbeni umjovo. Ngokwezidingo zokuklama isikhunta, i-fluidity yamapulasitiki asetshenziswa ngokuvamile ingahlukaniswa izigaba ezintathu:

①I-PA enhle yoketshezi, VULIWE, PS, PP, CA, i-poly(4) i-methylpentene:

②I-resin yochungechunge lwe-Polystyrene enoketshezi olumaphakathi (njenge ABS, AS), PMMA, I-POM, i-polyphenylene ether;

③Ukungabi namanzi kahle: I-PC, i-PVC eqinile, i-polyphenylene ether, i-polysulfone, polyarylsulfone, i-fluoroplastics.

I-fluidity yamapulasitiki ahlukahlukene nayo iyashintsha ngenxa yezinto ezihlukahlukene zokubumba. Izici eziyinhloko ezinomthelela zimi kanje:

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①Izinga lokushisa eliphakeme lezinto ezibonakalayo linyusa uketshezi, kodwa amapulasitiki ahlukene anomehluko wawo, njenge-PS (ikakhulukazi labo abanokumelana nomthelela omkhulu kanye nenani eliphakeme le-MFR), PP, PA, PMMA, i-polystyrene eshintshiwe (njenge ABS, AS) I-fluidity ye, I-PC, I-CA namanye amapulasitiki ahluka kakhulu ngezinga lokushisa. Okwe-PE kanye ne-POM, ukwanda kwezinga lokushisa noma ukwehla kunomphumela omncane ku-fluidity yabo. Ngakho-ke, owokuqala kufanele alungise izinga lokushisa ngesikhathi sokubumba ukuze ulawule uketshezi.

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② Njengoba ingcindezi yokubumba umjovo ikhula, impahla encibilikisiwe ingaphansi kokugunda okukhulu kanye nokumanzi, ikakhulukazi i-PE ne-POM zizwela kakhulu, ngakho-ke ukucindezela komjovo kufanele kulungiswe ukuze kulawulwe uketshezi ngesikhathi sokubunjwa.

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③Ifomu, ubungako, isakhiwo, ukuklama uhlelo lokupholisa, ukumelana nokugeleza kwezinto ezincibilikisiwe (njengokuphela kwendawo, ubukhulu besigaba sesiteshi, ukuma komgodi, isistimu yokukhipha umoya) nezinye izici zesistimu yokubunjwa kwesakhiwo sesikhunta zithinta ngokuqondile izinto ezincibilikisiwe emgodini I-fluidity yangempela ngaphakathi, uma impahla encibilikisiwe ikhuthazwa ukwehlisa izinga lokushisa futhi ikhulise ukumelana ne-fluidity, i-fluidity izokwehla.

Lapho uklama isikhunta, isakhiwo esinengqondo kufanele sikhethwe ngokusho kwe-fluidity yepulasitiki esetshenzisiwe. Ngesikhathi sokubumba, izinga lokushisa lempahla, izinga lokushisa lesikhunta, ingcindezi yomjovo, isivinini somjovo nezinye izici zingabuye zilawulwe ukuze kulungiswe ngokufanele isimo sokugcwalisa ukuze kuhlangatshezwane nezidingo zokubumba.

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I-Crystalline thermoplastics ingahlukaniswa ngamapulasitiki acwebile futhi angewona amakristalu (eyaziwa nangokuthi i-amorphous) amapulasitiki ngokusho kokungabikho kwawo kwecrystallization ngesikhathi sokufiphala. Okubizwa ngokuthi i-crystallization phenomenon ibhekisela eqinisweni lokuthi lapho ipulasitiki ishintsha isuka esimweni esincibilikisiwe ibe yisimo sokufingqa., ama-molecule ahamba ngokuzimela futhi asesimweni esiphazamisekile ngokuphelele. Ama-molecule ayeka ukuhamba ngokukhululeka, cindezela indawo emile kancane, futhi ube nokuthambekela kokwenza ukuhlelwa kwamangqamuzana kube imodeli evamile. Lesi simo.

Indlela yokubukeka yokwahlulela lezi zinhlobo ezimbili zamapulasitiki inganqunywa ngokusobala kwezingxenye zepulasitiki ezinodonga oluqinile.. Ngokuvamile, izinto zekristalu ziyi-opaque noma ziyashintshashintsha (njenge-POM, njll.), futhi izinto ze-amorphous zisobala (njenge-PMMA, njll.). Kodwa kukhona okuhlukile. Ngokwesibonelo, i-poly(4) I-methylpentene iyipulasitiki ecwebezelayo kodwa inokucaca okuphezulu, futhi i-ABS iyinto e-amorphous kodwa ayibonisi obala.

Lapho uklama isikhunta nokukhetha imishini yokubumba umjovo, qaphela lezi zidingo ezilandelayo kanye nezinyathelo zokuphepha zamapulasitiki acwebile:

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① Ukushisa okuningi kuyadingeka ukuze izinga lokushisa likhuphukele kuzinga lokushisa lokubumba, kanye nemishini enekhono elikhulu lokwenza ipulasitiki iyadingeka. Ku

②Ikhipha inani elikhulu lokushisa ngesikhathi sokupholisa futhi idinga ukupholiswa ngokwanele.

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③Umehluko othize wamandla adonsela phansi phakathi kwesimo esincibilikisiwe nesimo esiqinile mkhulu, ukuncipha kokubumba kukhulu, futhi ukuncipha kanye nezimbotshana zivame ukwenzeka.

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④ Ukupholisa okusheshayo, ubucwebe obuphansi, ukuncipha okuncane kanye nokubonakala okuphezulu. I-crystallinity ihlobene nokuqina kodonga lwengxenye yepulasitiki, futhi ukujiya kodonga kuyaphuza ukuphola, icrystallinity iphezulu, ukushwabana kukhulu, futhi izici ezibonakalayo zinhle. Ngakho-ke, izinga lokushisa lesikhunta se-crystalline material kufanele lilawulwe njengoba kudingeka.

⑤I-anisotropy ebalulekile nengcindezi enkulu yangaphakathi. Ama-molecule angacwebezeli ngemva kokudilizwa anomkhuba wokuqhubeka nokucwebezela, zisesimweni sokungalingani kwamandla, futhi bathambekele ekuphendukeni kanye ne-warpage. ⑥ Ibanga lokushisa elicwebezelayo lincane, futhi into engancibilikisiwe ijwayele ukujovwa esikhunjeni noma ivimbe imbobo yokuphakelayo.

Ukuzwela ukushisa kubhekisela ekuthambekeni kwamapulasitiki athile ukuzwela kakhulu ukushisa. Uma kushisa emazingeni okushisa aphezulu isikhathi eside noma ingxenye yembobo yokuphakelayo incane kakhulu, lapho umphumela wokugunda umkhulu, izinga lokushisa lezinto ezibonakalayo liyakhula kanye nokuthambekela kokushintsha umbala, ukucekelwa phansi, futhi ukubola kwenzeka. Ipulasitiki ibizwa ngepulasitiki engezwani nokushisa.

Njenge-PVC eqinile, i-polyvinylidene chloride, i-vinyl acetate copolymer, I-POM, i-polychlorotrifluoroethylene, njll. Amapulasitiki azwela ukushisa akhiqiza ama-monomers, amagesi, okuqinile kanye neminye imikhiqizo ngesikhathi sokubola. Ngokuqondene, amanye amagesi okubola anokucasuka, ezonakalisayo noma ezinobuthi emzimbeni womuntu, imishini, kanye nezibunjwa. Ngakho-ke, ukunakwa kufanele kukhokhwe ukuklama isikhunta, ukukhethwa komshini wokubumba umjovo nokubumba. Umshini wokubumba umjovo wesikulufu kufanele usetshenziswe. Ingxenye yesistimu yokuthela kufanele ibe nkulu. Isikhunta kanye nomgqomo kufanele kufakwe i-chrome-plated. Akufanele kube khona ukuminza ekhoneni. I izinga lokushisa lokubumba kumele ilawulwe ngokuqinile. Isiqinisi, yenza buthaka ukusebenza kwayo okuzwela ukushisa.

Abanye amapulasitiki (njenge-PC) ngisho nenani elincane lamanzi, kodwa zizobola ngaphansi kokushisa okuphezulu nokucindezela okukhulu. Lesi sakhiwo sibizwa nge-easy hydrolysis, okumele ishiswe futhi yomiswe kusenesikhathi.

Uma unemibuzo kuumjovo ukubumba inqubo,plz sicela usibuze,sizokunikeza isevisi engcono kakhulu!

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