Ikhwalithi yama-PET preforms
I-Polyethylene terephthalate (PET), eyaziwa kakhulu ngokuthi i-polyester, iyinto yepulasitiki esetshenziswa kabanzi. Ukukhiqizwa kwe Amabhodlela e-PET ingahlukaniswa ngezinqubo ezimbili eziyinhloko ngokusekelwe ohlotsheni lwe-preform: ukubumba i-injection stretch blow molding (ISBM) kanye nokubumba i-extrusion stretch blow molding (ESBM). Phakathi kwalezi zindlela ezimbili, i-ISBM ivame kakhulu ngenxa yokulula kwayo ukulawula, ukusebenza kahle kokukhiqiza okuphezulu, kanye nesilinganiso esiphansi se-scrap. Enqubweni yokwenza i-blow-molded amabhodlela okuhlobisa, Ama-PET chips afakwa kuqala ku-preform. Kudingeka ukuthi ingxenye yezinto ezisetshenzisiwe akufanele ibe phezulu kakhulu (ngaphansi kuka-5%), futhi ukuphinda kusetshenziswe akufanele kudlule izikhathi ezimbili. Isisindo sama-molecule kanye ne-viscosity akufanele kube phansi kakhulu (isisindo sama-molecule 31,000 - 50,000, i-intrinsic viscosity 0.78 - 0.85 cm³/g). NgokoMthetho Kazwelonke Wokuphepha Kokudla, izinto ezisetshenzisiwe azivunyelwe ukusetshenziswa ekupakisheni ukudla nemithi. Ama-preform akhiqizwa ngokubumba nge-injection kudingeka agcinwe isikhathi esingaphezu kwamahora angama-24 ngaphambi kokusetshenziswa. Ama-preform angasetshenziswanga ngemva kokushisa kumele agcinwe isikhathi esingaphezu kwamahora angama-48 ngaphambi kokufudumala kabusha.
Isikhathi sokugcina amabhodlela okuhlobisa akufanele kudlule izinyanga eziyisithupha. Ikhwalithi yama-preform incike kakhulu kwikhwalithi yezinto ze-PET. Ngakho-ke, kubalulekile ukukhetha izinto ezilula ukuzifutha nokuyibumba, nokuthuthukisa inqubo efanele yokwakha i-preform. Ukuhlolwa kubonisa ukuthi ama-preform enziwe ngezinto zokusetshenziswa ezingenisiwe kulula ukuwafutha kunalawo enziwe ngezinto zokusetshenziswa zasekhaya ezine-viscosity efanayo. Kodwa-ke, kuma-preform e-batch efanayo, izinsuku zokukhiqiza ezahlukene zingadinga izinqubo ezahlukene zokufutha. Ikhwalithi yama-preform inquma ubunzima benqubo yokufutha. Izidingo zama-preforms Amabhodlela e-PET kufaka phakathi ukuba msulwa, okusobala, okungenazo izinto ezingcolile nombala, ubude bendawo yokujova obufanele kanye ne-halo eyizungezile.
Okokuqala, ubukhulu be-preform ye Amabhodlela e-PET kubalulekile esitsheni sokugcina sokupakisha. Lapho kunqunywa usayizi we-preform, into yokuqala okufanele icatshangelwe yinhloso amabhodlela okuhlobisaIngabe kungenxa yokudla, iziphuzo, izimonyo, noma eminye imikhakha? Izinjongo ezahlukene zingadinga izimo ezahlukene kanye namandla amabhodlela ezimonyo. Ngokucabangela ngokucophelela izidingo zamandla omkhiqizo, amandla e-preform anganqunywa, futhi kungakhethwa isimo esifanele, njengesiyingi, isikwele, noma i-oval.
Okwesibili, ububanzi bentamo (noma umlomo) buyipharamitha ebalulekile. Uma ulinganisa intamo, qiniseka ukuthi isilinganiso sivundlile ukuze uthole usayizi oqondile wobubanzi. Ubukhulu bentamo buthinta ngqo ukusebenza kokugcwalisa nokuthulula Amabhodlela e-PETImikhiqizo ehlukene ingadinga osayizi abahlukene bentamo, ngakho-ke ukukhetha intamo okunengqondo kuyadingeka lapho uklama ibhodlela.
Okokugcina, isisindo se-preform sibhekisela esisindweni se- amabhodlela okuhlobisa, okuhlanganisa nomzimba nentamo. Isisindo singalinganiswa ngokunembile ngokukala noma ngokusebenzisa isikali esijikelezayo. Ukunqunywa kwesisindo kuhlobene ngqo namandla nokuqina kwebhodlela. Uma ucabangela isisindo, kubalulekile ukulinganisela amandla esakhiwo sebhodlela kanye nezindleko zezinto zokwakha ukuqinisekisa ukuthi umkhiqizo wokugcina unamandla anele futhi uhlangabezana nezidingo zomnotho.
Sekukonke, usayizi, ububanzi bentamo, kanye nesisindo se-preform ye Amabhodlela e-PET yizinto ezibalulekile okufanele zicatshangelwe esigabeni sokuklama amabhodlela epulasitikiNgokulinganisa ngokucophelela nokukhetha la mapharamitha ngokufanele, kungenzeka ukuqinisekisa ukuthi ibhodlela lokugcina lihlangabezana nezidingo zomkhiqizo kanye nezindinganiso zomkhakha, okuhlinzeka ngokusebenza kahle kakhulu kokupakisha. Ngesikhathi senqubo yokukhiqiza amabhodlela, ukunaka okuqhubekayo ekulawulweni kwala mapharamitha kuzosiza ekukhiqizeni amabhodlela epulasitiki asezingeni eliphezulu.