Embonini yomjovo wesikhunta, kuvame ukuthi kube nabangenayo abasha embonini ababonayo: Kungani izinga lokushisa lomjovo womjovo lenyusa isicwebezelisi sezingxenye zepulasitiki ezikhiqizwayo? Manje sisebenzisa ulimi olulula ukucacisa lo mkhuba, futhi sichaze ukuthi sikhetha kanjani ukushisa kwesikhunta ngokufanele. Isitayela sokubhala sinqunyelwe, ngakho-ke sicela useluleke uma kungalungile! (Lesi sahluko sikhuluma kuphela ngokushisa kwesikhunta, ingcindezi nokunye kungaphezu kwengxoxo)
1. Ithonya lokushisa kwesikhunta ekubukekeni:
Okokuqala, uma izinga lokushisa lesikhunta liphansi kakhulu, lizonciphisa ukuncibilika kwamanzi futhi i-undershoot ingenzeka; lokushisa isikhunta kuthinta crystallinity we plastic. Ukuze ABS, uma lokushisa isikhunta liphansi kakhulu, sekugcineni umkhiqizo kuyoba ongaphakeme. Uma kuqhathaniswa nokugcwaliswa, amapulasitiki kulula ukuthuthela ebusweni lapho izinga lokushisa liphakeme. Ngakho-ke, lapho izinga lokushisa lesikhunta somjovo liphezulu, ingxenye yepulasitiki isondele kakhulu ebusweni besikhunta somjovo, ukugcwaliswa kuzoba ngcono, futhi ukukhanya nokucwebezela kuzobe kuphakeme. Kodwa-ke, ukushisa kwesikhunta somjovo akufanele kube phezulu kakhulu. Uma liphezulu kakhulu, kulula ukunamathela kusikhunta, futhi kuzoba khona amabala akhanyayo asobala kwezinye izingxenye zengxenye yepulasitiki. Uma izinga lokushisa lesikhunta somjovo liphansi kakhulu, lizophinda futhi lenze ingxenye yepulasitiki ibambe isikhunta ngokuqinile, futhi kulula ukuhluza ingxenye yepulasitiki lapho idilizwa, ikakhulukazi iphethini ebusweni bengxenye yepulasitiki.
Multi-esiteji umjovo udini ongaxazulula inkinga isikhundla. Isibonelo, uma umkhiqizo unezintambo zegesi lapho umkhiqizo ujojowe, ungahlukaniswa ngezigaba. Emkhakheni wokubumba umjovo, ngemikhiqizo ecwebezelayo, ukuphakama kwesikhunta kuyanda, isicwebezelisi sendawo yomkhiqizo siyaphakama. Ngokuphambene nalokho, lapho izinga lokushisa liphansi, isicwebezelisi sobuso siphansi. Kepha kwimikhiqizo eyenziwe ngezinto ze-PP eziphrintwe yilanga, ukuphakama kwezinga lokushisa, ukwehla kokucwebezela kobuso bomkhiqizo, ukucwebezela okuphansi, ukuphakama kokwahluka kombala, futhi umehluko we-gloss nombala ulingana ngokuhlukile.
Ngakho-ke, inkinga ejwayelekile kunazo zonke ebangelwa ukushisa kwesikhunta ukuphela komhlaba okweqile kwezingxenye ezibunjiwe, okuvame ukubangelwa ukushisa kwesikhunta esiphansi kakhulu.
I-shrinkage yokubumba kanye ne-post-molding shrinkage yama-polymers ama-semi-crystalline ngokuyinhloko ancike ekushiseni kwesikhunta nobukhulu bodonga lwengxenye. Ukusatshalaliswa kwamazinga okushisa okungalingani kusikhunta kuzodala ukuncipha okuhlukile, okwenza kube nzima ukuqinisekisa ukuthi izingxenye zihlangabezana nokubekezelelana okucacisiwe. Esimweni esibi kakhulu, noma ngabe i-resin esetshenzisiwe ayifakwanga amandla noma igcizelelwe i-resin, i-shrinkage idlula inani elilungisekayo.
2. Umthelela kusayizi womkhiqizo:
Uma izinga lokushisa lesikhunta liphezulu kakhulu, ukuncibilika kuzobola ngokushisa. Ngemuva kokuphuma komkhiqizo, izinga lokuncipha emoyeni lizokhula, nosayizi womkhiqizo uzoba mncane. Uma isikhunta sisetshenziswa ezimweni zokushisa eziphansi, uma ubukhulu bengxenye buba bukhulu, ngokuvamile kungenxa yobuso besikhunta. Izinga lokushisa liphansi kakhulu. Lokhu kungenxa yokuthi izinga lokushisa lesikhunta liphansi kakhulu, futhi umkhiqizo uncipha kancane emoyeni, ngakho ubukhulu bukhulu! Isizathu ukuthi izinga lokushisa eliphansi lesikhunta lisheshisa i-molekyuli "ukuma okufriziwe", okwandisa ubukhulu besendlalelo esifriziwe sokuncibilika emgodini wesikhunta. Ngasikhathi sinye, izinga lokushisa eliphansi lesikhunta livimbela ukukhula kwamakristalu, ngaleyo ndlela kuncishiswe ukuncipha komkhiqizo. Ngokuphambene nalokho, uma izinga lokushisa lesikhunta liphezulu, ukuncibilika kuzophola kancane, isikhathi sokuphumula sizoba side, izinga lokuqondisa lizobe liphansi, futhi kuzoba yinzuzo ku-crystallization, futhi ukuncipha kwangempela komkhiqizo kuzoba kukhulu.
Uma inqubo yokuqalisa yinde kakhulu ngaphambi kokuba usayizi uzinze, lokhu kukhombisa ukuthi izinga lokushisa lesikhunta alilawulwa kahle, ngoba isikhunta sithatha isikhathi eside ukufinyelela ukulingana okushisayo.
Ukuhlakazeka kokushisa okungalingani ezingxenyeni ezithile zesikhunta kuzokwandisa kakhulu umjikelezo wokukhiqiza, ngaleyo ndlela kwandise izindleko zokubumba! Ukushisa kwesikhunta okujwayelekile kunganciphisa ukuguquguquka kokuncipha kokubumba futhi kuthuthukise ukuzinza kwento. I-crystalline plastic, izinga lokushisa eliphakeme lesikhunta lihambisana nenqubo ye-crystallization, izingxenye zepulasitiki ezifakwe ngokuphelele ngeke zishintshe ngosayizi ngesikhathi sokugcina noma sokusebenzisa; kodwa i-crystallinity ephezulu nokuncipha okukhulu. Kuma-plastiki athambile, izinga lokushisa eliphansi lesikhunta kufanele lisetshenziswe ekwakheni, okulungele ukuzinza kobukhulu. Kunoma iyiphi into, izinga lokushisa lesikhunta lihlala likhona futhi ukuncipha kuyavumelana, okuzuzisa ukuthuthukisa ukunemba okuyisilinganiso!
3. Ithonya lokushisa kwesikhunta ku-deformation:
Uma uhlelo lokupholisa isikhunta lungakhiwanga kahle noma izinga lokushisa lesikhunta lingalawulwa kahle, ukupholisa okunganele kwezingxenye zepulasitiki kuzobangela ukuthi izingxenye zepulasitiki zikhule futhi zikhubazeke. Ukuze kulawulwe ukushisa kwesikhunta, umehluko wezinga lokushisa phakathi kwesikhunta sangaphambili nesikhunta sangemuva, umnyombo wesikhunta nodonga lwesikhunta, nodonga lwesikhunta kanye nokufakwa kufanele kunqunywe ngokuya ngezici zomkhiqizo, ukuze lawula umehluko kusivinini sokupholisa nokuncipha kwengxenye ngayinye yesikhunta. Ngemuva kokudicilela phansi, ijwayele ukugoba ohlangothini lokudonsa ohlangothini lokushisa oluphakeme ukuze kunciphise umehluko ekunciphiseni kwe-orientation futhi kugweme ukusonteka nokukhubazeka kwengxenye yepulasitiki ngokomthetho wokuqondisa.
Ezingxenyeni zepulasitiki ezinesakhiwo esilinganayo ngokuphelele, izinga lokushisa lesikhunta kufanele ligcinwe lingaguquguquki ngokufanele, ukuze ukupholisa kwengxenye ngayinye yengxenye yepulasitiki kulinganiswe. Izinga lokushisa isikhunta uzinzile futhi Ukupholisa olinganiselayo, okuyinto kunganciphisa ukusonteka ingxenye plastic. Ukweqisa okushisa ngokweqile kwesikhunta kuzodala ukupholisa okungalingani kwezingxenye zepulasitiki kanye nokuncipha okungahambelani, okuzodala ukucindezeleka futhi kubangele i-warpage nokukhubazeka kwezingxenye zepulasitiki, ikakhulukazi izingxenye zepulasitiki ezinokulingana kodonga olungalingani nobubunzima obuyinkimbinkimbi. Uhlangothi olunezinga eliphezulu lokushisa kwesikhunta, ngemuva kokuthi umkhiqizo selehlile, ukuqondiswa kokuguqulwa kufanele kube ohlangothini lokushisa okuphezulu kwesikhunta! Kunconywa ukuthi kukhethwe izinga lokushisa lesikhunta sangaphambili nangemuva ngokuvumelana nezidingo. Izinga lokushisa lesikhunta likhonjiswa etafuleni lezakhiwo zomzimba lezinto ezahlukahlukene!
4. Ithonya lokushisa kwesikhunta kuzakhiwo zemishini (ukucindezeleka kwangaphakathi):
Izinga lokushisa lesikhunta liphansi, futhi uphawu lwe-weld lwengxenye yepulasitiki lusobala, okunciphisa amandla omkhiqizo; ukukhuphuka kobukhazikhazi bepulasitiki yamakristalu, kukhulu ukuthambekela kwengxenye yepulasitiki ekucindezelekeni kokuqhekeka; ukuze unciphise ukucindezela, izinga lokushisa lesikhunta akufanele libe phezulu kakhulu (PP, PE). Okwe-PC namanye amaplastiki aphezulu e-viscosity amorphous, ukuqhekeka kwengcindezi kuhlobene nengcindezi yangaphakathi yengxenye yepulasitiki. Ukwandisa izinga lokushisa kwesikhunta kulungele ukunciphisa ukucindezeleka kwangaphakathi nokunciphisa ukuthambekela kokuqhekeka kwengcindezi.
Ukuvezwa kwengcindezi yangaphakathi kuyizimpawu ezisobala zokucindezeleka! Isizathu ukuthi: ukwakheka kwengcindezi yangaphakathi ekubunjweni kubangelwa amazinga e-thermal shrinkage ahlukile ngesikhathi sokupholisa. Ngemuva kokuthi umkhiqizo ubunjiwe, ukupholisa kwawo kancane kancane kusuka ebusweni kuye ngaphakathi. Ubuso buqala bunciphe buqine, bese buya kancane buye ngaphakathi. Ukucindezela kwangaphakathi kwenziwa ngenxa yomehluko wejubane lokuncipha. Lapho ingcindezi yangaphakathi eyinsalela engxenyeni yepulasitiki ingaphezulu komkhawulo wokunwebeka we-resin, noma ngaphansi kokuguguleka kwendawo ethile yamakhemikhali, imifantu izokwenzeka ebusweni bengxenye yepulasitiki. Ukucwaninga kuma-resins asobala we-PC ne-PMMA kukhombisa ukuthi ingcindezi yangaphakathi eyinsalela isesimweni esicindezelwe kusendlalelo esingaphezulu kanye nefomu eleluliwe kusendlalelo sangaphakathi.
Ukucindezela komhlaba okucindezelayo kuncike esimweni sokupholisa ebusweni. Isikhunta esibandayo sipholisa ngokushesha i-resin encibilikisiwe, ebangela ukuthi umkhiqizo obunjiwe ukhiqize ukucindezeleka kwangaphakathi okusele okuphezulu. Izinga lokushisa lesikhunta yisimo esiyisisekelo sokulawula ukucindezeleka kwangaphakathi. Ushintsho oluncane lokushisa kwesikhunta luzoshintsha kakhulu ukucindezela kwangaphakathi okusele kwalo. Ngokuvamile, ukucindezeleka kwangaphakathi okwamukelekayo komkhiqizo ngamunye ne-resin kunomkhawulo wokushisa wesikhunta. Lapho ubumba izindonga ezincanyana noma ukuhamba amabanga amade, izinga lokushisa lesikhunta kufanele libe likhulu kunesilinganiso sokubunjwa okujwayelekile.
5. Thinta ukushisa kokushiswa komkhiqizo okushisayo:
Ikakhulukazi kuplastikhi wamakristalu, uma umkhiqizo ubunjwe ezingeni lokushisa eliphansi lesikhunta, ukuma kwamangqamuzana namakristalu ngokushesha kumisiwe. Lapho indawo yokusebenzisa izinga lokushisa ephakeme noma izimo zokucubungula zesibili, uchungechunge lwamangqamuzana luzohlelwa kabusha ngokwengxenye Futhi inqubo ye-crystallization yenza ukukhubazeka komkhiqizo kube ngaphansi kakhulu kwezinga lokushisa lokuhlanekezela kokushisa (i-HDT) kwalolo daba.
Indlela eyiyo ukusebenzisa ukushisa kwesikhunta okunconyiwe okuseduze nezinga lokushisa le-crystallization ukwenza umkhiqizo ukhanyiswe ngokuphelele esigabeni sokubunjwa komjovo, ukugwema lolu hlobo lwe-post-crystallization kanye ne-post-shrinkage endaweni enezinga eliphezulu lokushisa. Ngamafuphi, ukushisa kwesikhunta kungenye yemingcele yokulawula eyisisekelo kunqubo yokubumba umjovo, futhi kubhekwe futhi ngokuyinhloko ekwakhiweni kwesikhunta.
Izincomo zokunquma ukushisa okulungile kwesikhunta:
Kulezi zinsuku, isikhunta sesiyinkimbinkimbi ngokwengeziwe, ngakho-ke, kuye kwaba nzima ngokwengeziwe ukudala izimo ezifanele ukulawula kahle ukushisa kokubumba. Ngaphezu kwezingxenye ezilula, uhlelo lokulawula ukushisa lokushisa luvame ukuyekethisa. Ngakho-ke, izincomo ezilandelayo ziyisiqondiso esinzima.
Esigabeni sokuklanywa kwesikhunta, ukulawula ukushisa kokuma kwengxenye esetshenzisiwe kufanele kubhekwe.
Uma ukuklama isikhunta esinomthamo omncane wokujova nosayizi omkhulu wokubumba, kubalulekile ukuthi ubheke ukudluliswa okuhle kokushisa.
Yenza izibonelelo lapho kuklanywa ubukhulu obunqamulelayo boketshezi olugeleza phakathi kwesikhunta naseshubhu yokuphakelayo. Ungawasebenzisi amalunga, ngaphandle kwalokho kuzodala izithiyo ezinkulu ekugelezeni koketshezi okulawulwa ukushisa kwesikhunta.
Uma kunokwenzeka, sebenzisa amanzi acindezelwe njengendawo yokulawula izinga lokushisa. Sicela usebenzise amapayipi nezinqwaba eziphikisana nengcindezi ephezulu nokushisa okuphezulu.
Nikeza incazelo eningiliziwe yokusebenza kwemishini yokulawula izinga lokushisa efana nesikhunta. Ishidi lemininingwane elinikezwe ngumenzi wesikhunta kufanele linikeze izibalo ezithile ezidingekayo mayelana nezinga lokugeleza.
Sicela usebenzise amapuleti wokuvikela ukugqagqana phakathi kwesikhunta nethempulethi yomshini.
Sebenzisa amasistimu wokulawula ukushisa ahlukahlukene ngesikhunta esiguqukayo nesilungisiwe
Kunoma yiluphi uhlangothi naphakathi nendawo, sicela usebenzise uhlelo olukude lokulawula ukushisa, ukuze kube namazinga okushisa ahlukene aqala ngesikhathi senqubo yokubumba.
Amasekethe ohlelo lokulawula ukushisa ahlukile kufanele axhunywe ochungechungeni, hhayi ngokufana. Uma amasekethe exhunywe ngokufana, umehluko ekumelaneni uzodala ukuthi isilinganiso sokugeleza kwevolumetric yesilinganiso sokulawula izinga lokushisa sihluke, okuzodala ushintsho olukhulu lokushisa kunaseseketheni ochungechungeni. (Kuphela lapho isekethe yochungechunge ixhunywe ethekwini lesikhunta nomehluko wokushisa we-outlet ungaphansi kuka-5 ° C, ukusebenza kwawo kukuhle)
Kuyinzuzo ukubonisa ukushisa kokuphakela nokubuyisa lokushisa kumishini yokulawula ukushisa kwesikhunta.
Inhloso yokulawulwa kwenqubo ukufaka inzwa yokushisa kusikhunta ukuze izinguquko zokushisa zitholakale ekukhiqizeni kwangempela.
Emjikelezweni wonke wokukhiqiza, ibhalansi yokushisa isungulwa kwisikhunta ngokusebenzisa imijovo eminingi. Ngokuvamile, kufanele okungenani kube nemijovo eyi-10. Ukushisa kwangempela ekufinyeleleni kokulingana okushisayo kuthintwa yizici eziningi. Izinga lokushisa langempela lobuso besikhunta elihlangana nepulasitiki lingalinganiswa nge-thermocouple ngaphakathi kwesikhunta (kufundwa ku-2mm ebusweni). Indlela ejwayelekile kakhulu ukubamba i-pyrometer ukukala, futhi iphenyo ye-pyrometer kufanele iphendule ngokushesha. Ukunquma ukushisa kwesikhunta, amaphuzu amaningi kufanele alinganiswe, hhayi ukushisa kwephoyinti elilodwa noma uhlangothi olulodwa. Ngemuva kwalokho ingalungiswa ngokuya ngesilinganiso sokulawula izinga lokushisa. Lungisa ukushisa kwesikhunta kunani elifanele. Izinga lokushisa lesikhunta elinconywayo linikezwa ohlwini lwezinto ezahlukahlukene. Lezi ziphakamiso zivame ukunikezwa kucatshangelwa ukucushwa okuhle phakathi kwezinto ezifana nokuqedwa kobuso obuphezulu, izakhiwo zemishini, ukuncipha kanye nemijikelezo yokucubungula.
Okwabumba okudinga ukucubungula izingxenye zokunemba kanye nesikhunta okufanele sihlangabezane nezidingo eziqinile ezimeni zokubukeka noma izingxenye ezithile zokuphepha ezijwayelekile, amazinga okushisa aphezulu wesikhunta avame ukusetshenziswa ). Ezingxenyeni ezinezidingo zobuchwepheshe eziphansi nezindleko zokukhiqiza ziphansi ngangokunokwenzeka, amazinga okushisa aphansi okucubungula angasetshenziswa ngesikhathi sokubumba. Kodwa-ke, umenzi kufanele aqonde ukushiyeka kwalokhu kukhetha futhi ahlole ngokucophelela izingxenye ukuqinisekisa ukuthi izingxenye ezikhiqizwayo zingahlangabezana nezidingo zamakhasimende.
