Tarihin Injinan Fitar Filastik

Fitar robobi wani tsari ne mai girma na masana'anta wanda aka narkar da danyen filastik kuma a samar da shi zuwa bayanan martaba mai ci gaba. Extrusion yana samar da abubuwa kamar bututu / tubing, yanayin yanayi, shinge, shinge na bene, firam ɗin taga, fina-finai na filastik da zanen gado, suturar thermoplastic, da rufin waya.
Wannan tsari yana farawa ta hanyar ciyar da kayan filastik (pellets, granules, flakes ko foda) daga hopper zuwa cikin ganga na extruder. Ana narkar da kayan a hankali ta hanyar makamashin injin da aka samar ta hanyar juya sukurori da na'urorin dumama da aka shirya tare da ganga. Ana tilastawa narkakkar polymer ɗin a cikin mutuwa, wanda ke siffanta polymer ɗin zuwa siffar da ke taurare yayin sanyaya.

TARIHI

bututu extrusion
Abubuwan farko na farko na extruder na zamani sun samo asali ne a farkon karni na 19. A shekara ta 1820, Thomas Hancock ya ƙirƙira wani “masticator” na roba wanda aka ƙera don kwato tarkacen robar da aka sarrafa, kuma a shekara ta 1836 Edwin Chaffee ya ƙera na'ura mai jujjuyawa guda biyu don haɗa abubuwan da ake buƙata a cikin roba. Na farko thermoplastic extrusion a cikin 1935 Paul Troester da matarsa ​​Ashley Gershoff a Hamburg, Jamus. Ba da daɗewa ba, Roberto Colombo na LMP ya ƙirƙira tagwaye na farko a Italiya.

TSARI
A cikin extrusion na robobi, danyen fili abu ne yawanci a cikin nau'i na nordles (kananan beads, sau da yawa ake kira resin) wanda ake ciyar da nauyi daga saman hawa hopper zuwa cikin ganga na extruder. Ana amfani da ƙari kamar masu launi da masu hana UV (a cikin ruwa ko nau'in pellet) sau da yawa kuma ana iya haɗa su cikin guduro kafin isa wurin hopper. Tsarin yana da alaƙa da yawa tare da gyare-gyaren filastik filastik daga ma'anar fasahar extruder, kodayake ya bambanta da cewa yawanci tsari ne mai ci gaba. Duk da yake pultrusion na iya ba da bayanan martaba iri ɗaya da yawa a cikin tsayin daka, yawanci tare da ƙarin ƙarfafawa, ana samun wannan ta hanyar cire samfurin da aka gama daga mutuwa maimakon fitar da polymer narke ta hanyar mutuwa.

Kayan yana shiga ta cikin makogwaron abinci (buɗe kusa da baya na ganga) kuma ya zo cikin hulɗa tare da dunƙule. Juyawa mai jujjuyawa (yawanci yana jujjuyawa a misali 120 rpm) yana tilasta bead ɗin filastik gaba zuwa cikin ganga mai zafi. Yawan zafin jiki na extrusion da ake so yana da wuya ya zama daidai da saita zafin ganga saboda dumama danko da sauran tasirin. A yawancin matakai, ana saita bayanin martaba don ganga inda uku ko fiye masu zaman kansu na PID masu sarrafawa a hankali suna ƙara yawan zafin jiki daga baya (inda filastik ya shiga) zuwa gaba. Wannan yana ba da damar robobin filastik su narke a hankali yayin da ake tura su ta cikin ganga kuma suna rage haɗarin zafi wanda zai iya haifar da lalacewa a cikin polymer.

Ana samun ƙarin zafi ta hanyar matsananciyar matsi da gogayya da ke faruwa a cikin ganga. A gaskiya ma, idan layin extrusion yana gudana wasu kayan da sauri sosai, ana iya kashe na'urorin zafi kuma ana kiyaye zafin jiki ta hanyar matsa lamba da gogayya kawai a cikin ganga. A yawancin masu fitar da wuta, magoya bayan sanyaya suna nan don kiyaye zafin jiki ƙasa da ƙimar da aka saita idan an haifar da zafi mai yawa. Idan sanyaya iska ta tilas ba ta isa ba sannan ana amfani da jaket masu sanyaya sanyaya.

Filastik extruder yanke cikin rabi don nuna abubuwan da aka gyara
A gaban ganga, narkakkar robobin ya bar dunƙule ya bi ta cikin fakitin allo don cire duk wani gurɓataccen abu a cikin narkakkar. Ana ƙarfafa fuska ta hanyar faranti mai kauri (ƙaurin ƙarfe mai kauri tare da ramuka da yawa da aka haƙa ta cikinsa) tunda matsa lamba a wannan lokacin na iya wuce 5,000 psi (34 MPa). Kunshin allo / taron faranti shima yana aiki don haifar da matsin lamba a cikin ganga. Ana buƙatar matsa lamba na baya don narke iri ɗaya da haɗakar da ta dace na polymer, kuma yawan matsa lamba da aka haifar ana iya “tweaked” ta bambancin fakitin allo (yawan allo, girman saƙar waya, da sauran sigogi). Wannan farantin mai katsewa da haɗin fakitin allo shima yana kawar da “mowaƙwalwar jujjuyawa” na narkakken filastik kuma ya ƙirƙiri maimakon, “ƙwaƙwalwar ajiya mai tsayi”.
Bayan wucewa ta cikin farantin narkakkar filastik yana shiga cikin mutu. Mutuwa shine abin da ke ba samfurin ƙarshe bayanin martaba kuma dole ne a ƙera shi ta yadda narkakken robobi zai gudana a ko'ina daga bayanin martabar silinda, zuwa siffar bayanin martabar samfurin. Rashin daidaituwar kwarara a wannan matakin na iya samar da samfur tare da matsi maras so a wasu wurare a cikin bayanan martaba wanda zai iya haifar da yaƙe-yaƙe yayin sanyaya. Za'a iya ƙirƙirar nau'ikan sifofi iri-iri, an taƙaita su zuwa bayanan martaba masu ci gaba.

Dole ne a sanyaya samfurin a yanzu kuma ana samun wannan ta hanyar jawo extrudate ta hanyar wanka na ruwa. Filastik suna da insulators na thermal sosai don haka suna da wahalar sanyi da sauri. Idan aka kwatanta da karfe, filastik yana tafiyar da zafinsa sau 2,000 a hankali. A cikin bututu ko layin fitar da bututu, ana yin wankan ruwa da aka rufe ta hanyar injin da aka sarrafa a hankali don kiyaye sabuwar bututu ko narkakkar bututun daga rushewa. Don samfura irin su filastik filastik, ana samun sanyaya ta hanyar ja ta hanyar jujjuyawar sanyaya. Don fina-finai da zane-zanen bakin ciki sosai, sanyaya iska na iya zama tasiri a matsayin matakin sanyaya na farko, kamar yadda a cikin fitar da fim mai hurawa.
Hakanan ana amfani da masu fitar da filastik don sake sarrafa sharar filastik da aka sake yin fa'ida ko wasu albarkatun ƙasa bayan tsaftacewa, rarrabawa da/ko haɗawa. An fi fitar da wannan kayan zuwa cikin filaye masu dacewa don sarewa a cikin ƙwanƙwasa ko pellet don amfani da shi azaman mafari don ƙarin sarrafawa.

SCREW ZANIN
Akwai yankuna biyar masu yiwuwa a cikin dunƙule thermoplastic. Tun da ba a daidaita ma'anar kalmomi a cikin masana'antar ba, sunaye daban-daban na iya komawa ga waɗannan yankuna. Nau'o'in polymer daban-daban za su sami ƙirar dunƙule daban-daban, wasu ba za su haɗa duk yankuna masu yuwuwa ba.

Ƙaƙwalwar filastik mai sauƙi

Extruder sukurori Daga Boston Matthews
Yawancin sukurori suna da waɗannan yankuna uku:
● Yankin ciyarwa (wanda ake kira daskararrun isarwa yanki): wannan yanki yana ciyar da resin a cikin extruder, kuma zurfin tashar yawanci iri ɗaya ne a duk yankin.
● Yankin narkewa (wanda ake kira canjin canji ko matsawa): yawancin polymer yana narkewa a cikin wannan sashe, kuma zurfin tashar yana ƙara ƙarami.
Yanki mai auna (kuma ana kiransa yankin narkar da ruwa): wannan yanki yana narkar da barbashi na ƙarshe kuma yana gauraya zuwa daidaitaccen zafin jiki da abun da ke ciki. Kamar yankin ciyarwa, zurfin tashar yana dawwama a cikin wannan yanki.
Bugu da ƙari, dunƙule mai huɗawa (mataki biyu) yana da:
● Yanki na lalata. A cikin wannan yanki, kusan kashi biyu bisa uku na dunƙule, tashar ta fara zurfafawa, wanda ke sauƙaƙa matsa lamba kuma ya ba da damar duk wani iskar gas da ke danne (danshi, iska, kaushi, ko masu amsawa) don fitar da su ta hanyar vacuum.
● Yankin mita na biyu. Wannan yanki yayi kama da yankin aunawa na farko, amma tare da zurfin tashoshi. Yana hidima don sake matsawa narke don samun shi ta hanyar juriya na fuska da mutuwa.
Yawancin lokaci ana yin la'akari da tsayin dunƙule zuwa diamita kamar rabon L:D. Misali, dunƙule diamita 6-inch (150 mm) a 24:1 zai zama inci 144 (12 ft) tsayi, kuma a 32: 1 yana da inci 192 (16 ft) tsayi. Matsakaicin L:D na 25:1 na kowa ne, amma wasu injina suna zuwa 40:1 don ƙarin haɗawa da ƙarin fitarwa a diamita iri ɗaya. Sukurori mai hawa biyu (haɗe-haɗe) yawanci 36:1 ne don lissafin ƙarin yankuna biyu.
Kowane yanki an sanye shi da ɗaya ko fiye da ma'aunin zafi da sanyio ko RTD a bangon ganga don sarrafa zafin jiki. "Babban bayanin zafin jiki" watau, zafin jiki na kowane yanki yana da matukar muhimmanci ga inganci da halaye na extrudate na ƙarshe.

KAYAN TSORO NA AL'AMA

HDPE bututu a lokacin extrusion. Abun HDPE yana fitowa daga mai zafi, cikin mutu, sannan a cikin tanki mai sanyaya. Wannan bututun bututun na Acu-Power an haɗa shi - baƙar fata a ciki tare da jaket na orange na bakin ciki, don tsara igiyoyin wutar lantarki.
Abubuwan filastik na yau da kullun waɗanda ake amfani da su a cikin extrusion sun haɗa da amma ba'a iyakance ga: polyethylene (PE), polypropylene, acetal, acrylic, naylon (polyamides), polystyrene, polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS) da polycarbonate.[4] ]

MUTUWA IRI
Akwai nau'ikan mutuwa da ake amfani da su wajen fitar da robobi. Duk da yake za a iya samun bambance-bambance masu mahimmanci tsakanin nau'in mutuwa da rikitarwa, duk sun mutu suna ba da izinin ci gaba da extrusion na narke polymer, sabanin aiki mara ci gaba kamar gyaran allura.
Fuskar fim extrusion

Busa extrusion na filastik fim

Ana yin fim ɗin filastik don samfurori irin su jaka-jita-jita da ci gaba da zane-zane ta hanyar amfani da layin fim mai busa.
Wannan tsari iri ɗaya ne da tsarin extrusion na yau da kullun har ya mutu. Akwai manyan nau'ikan mutuwa guda uku da ake amfani da su a cikin wannan tsari: annular (ko crosshead), gizo-gizo, da karkace. Mutuwar annular sune mafi sauƙi, kuma dogara ga tashar narke polymer a kusa da dukan ɓangaren giciye na mutu kafin fita daga mutuwa; wannan zai iya haifar da rashin daidaituwa. Spider ya mutu yana kunshe da tsakiyar tsakiya wanda aka haɗe zuwa zobe na mutuwa ta waje ta hanyar adadin "ƙafafu"; yayin da kwararar ruwa ya fi daidaitawa fiye da mutuwar shekara-shekara, ana samar da layukan weld da yawa waɗanda ke raunana fim ɗin. Spiral ya mutu yana kawar da batun layin walda da kwararar asymmetrical, amma sun fi rikitarwa.

Ana sanyaya narke ɗan kaɗan kafin barin mutu don samar da bututu mai ƙarfi mai rauni. Ana faɗaɗa diamita na wannan bututu da sauri ta hanyar matsa lamba, kuma ana zana bututun zuwa sama tare da rollers, yana shimfiɗa filastik a cikin duka biyun kuma a zana kwatance. Zane da busa yana sa fim ɗin ya zama sirara fiye da bututun da aka fitar, sannan kuma ya fi dacewa ya daidaita sarƙoƙin ƙwayoyin cuta na polymer zuwa hanyar da ta ga mafi yawan nau'in filastik. Idan an zana fim ɗin fiye da yadda ake busa (diamita na ƙarshe na bututu yana kusa da diamita na extruded) ƙwayoyin polymer za su kasance masu daidaitawa sosai tare da jagorar zane, yin fim ɗin da ke da ƙarfi a wannan jagorar, amma rauni a cikin karkatacciyar hanya. . Fim ɗin da ya fi girma diamita fiye da diamita na extruded zai sami ƙarin ƙarfi a cikin karkatacciyar hanya, amma ƙasa da jagorar zana.
A cikin yanayin polyethylene da sauran polymers na semi-crystalline, yayin da fim ɗin ya sanyaya shi yana yin crystallizes a abin da aka sani da layin sanyi. Yayin da fim ɗin ke ci gaba da yin sanyi, ana zana shi ta nau'ikan rollers da yawa don karkata shi cikin tubing na kwance, wanda za'a iya yayyafa shi ko kuma a raba shi cikin nadi biyu ko fiye.

Sheet/fim extrusion
Ana amfani da extrusion Sheet/fim don fitar da zanen robobi ko fina-finan da suka yi kauri ba za a iya busa su ba. Akwai nau'ikan mutuwa iri biyu da ake amfani da su: T-dimbin yawa da rataye gashi. Manufar waɗannan sun mutu shine don sake daidaitawa da jagorar kwararar polymer narke daga fitowar zagaye guda ɗaya daga mai fitar zuwa sirara, kwararar tsari mai lebur. A cikin nau'ikan mutuwa guda biyu suna tabbatar da dindindin, iri ɗaya yana gudana a duk faɗin ɓangaren ƙetare na mutu. Yin sanyaya yawanci ta hanyar ja ta hanyar saitin naɗaɗɗen sanyaya (calender ko rolls "chill"). A cikin takardar extrusion, waɗannan Rolls ba kawai isar da zama dole sanyaya amma kuma ƙayyade takardar kauri da surface texture.[7] Sau da yawa ana amfani da haɗin gwiwa don amfani da yadudduka ɗaya ko fiye a saman kayan tushe don samun ƙayyadaddun kaddarorin kamar su sha UV, rubutu, juriya na iskar oxygen, ko tunanin kuzari.
Wani tsari na yau da kullun bayan extrusion don samfuran filastik shine thermoforming, inda takardar ta kasance mai zafi har sai tayi laushi (filastik), kuma an kafa ta ta hanyar mold zuwa sabon salo. Lokacin da aka yi amfani da vacuum, ana bayyana wannan a matsayin vacuum forming. Hannun kai (watau iyawa/samuwar yawan takardar da za a zana zuwa ga ƙira wanda zai iya bambanta a zurfin daga 1 zuwa 36 inci yawanci) yana da matukar mahimmanci kuma yana tasiri sosai ga ƙirƙirar lokutan zagayowar ga yawancin robobi.

Tubing extrusion
An ƙera bututun da aka cire, irin su bututun PVC, ta hanyar amfani da matattun mutuwa iri ɗaya kamar yadda ake amfani da su wajen fitar da fim. Za'a iya amfani da matsi mai kyau zuwa ga kogon ciki ta hanyar fil, ko kuma za'a iya amfani da matsi mara kyau zuwa diamita na waje ta amfani da ma'aunin injin don tabbatar da daidaitattun ƙimar ƙarshe. Ana iya gabatar da ƙarin lumen ko ramuka ta ƙara madaidaicin maɗauran ciki zuwa ga mutuwa.

Layin Extrusion Medical na Boston Matthews
Aikace-aikacen tubing da yawa kuma suna kasancewa a cikin masana'antar kera motoci, masana'antar famfo & dumama masana'antar shirya kaya.

Over jaket extrusion
Sama da jaket ɗin extrusion yana ba da damar aikace-aikacen filastik na waje akan waya ko kebul na data kasance. Wannan shine tsari na yau da kullun na insulating wayoyi.
Akwai nau'ikan nau'ikan nau'ikan mutuwa daban-daban da ake amfani da su don shafa kan waya, tubing (ko jaket) da matsa lamba. A cikin kayan aiki na jaket, narke polymer ba ya taɓa waya ta ciki har sai nan da nan kafin lebe ya mutu. A cikin kayan aiki na matsa lamba, narke yana hulɗa da waya ta ciki tun kafin ya kai ga leɓuna masu mutuwa; Ana yin wannan a babban matsin lamba don tabbatar da mannewa mai kyau na narkewa. Idan ana buƙatar kusanci ko mannewa tsakanin sabon Layer da waya data kasance, ana amfani da kayan aiki na matsa lamba. Idan ba a son mannewa / dole, ana amfani da kayan aikin jaket maimakon.

coextrusion
Coextrusion shine extrusion na abubuwa da yawa a lokaci guda. Wannan nau'in extrusion yana amfani da masu extruders biyu ko fiye don narke da kuma isar da tsayayyen kayan aiki na robobi daban-daban zuwa kan extrusion guda ɗaya (mutu) wanda zai fitar da kayan ta hanyar da ake so. Ana amfani da wannan fasaha akan kowane tsarin da aka bayyana a sama (fim ɗin busa, overjacketing, tubing, sheet). Ana sarrafa kauri mai kauri ta hanyar saurin dangi da girman masu fitar da kayan.

5:5 Layer co-extrusion na kwaskwarima "matsi" tube
A yawancin al'amuran duniya na gaske, polymer guda ɗaya ba zai iya biyan duk buƙatun aikace-aikacen ba. Ƙarfafawar haɗin gwiwa yana ba da damar ƙaddamar da kayan da aka haɗe, amma haɗin gwiwa yana riƙe da kayan daban-daban kamar yadudduka daban-daban a cikin samfurin extruded, yana ba da damar sanya kayan da ya dace tare da kaddarorin daban-daban kamar iskar oxygen, ƙarfi, taurin kai, da juriya.
Shafi extrusion
Rubutun cirewa yana amfani da tsarin fim ɗin busa ko jefar don sanya ƙarin Layer akan takarda, foil ko fim ɗin da ke akwai. Alal misali, ana iya amfani da wannan tsari don inganta halayen takarda ta hanyar rufe shi da polyethylene don sa ya fi tsayayya da ruwa. Hakanan za'a iya amfani da Layer extruded azaman manne don haɗa wasu abubuwa biyu tare. Tetrapak misali ne na kasuwanci na wannan tsari.

BAYANIN HUKUNCI
Haɗawa extrusion wani tsari ne wanda ke haɗa ɗaya ko fiye da polymers tare da ƙari don ba da mahadi na filastik. Ciyarwar na iya zama pellets, foda da/ko ruwaye, amma samfurin yawanci yana cikin nau'in pellet, don amfani da shi a cikin wasu hanyoyin ƙirƙirar filastik kamar extrusion da gyaran allura. Kamar yadda yake tare da extrusion na al'ada, akwai nau'i mai yawa a cikin girman inji dangane da aikace-aikacen da kayan aiki da ake so. Duk da yake ana iya amfani da na'urori guda ɗaya ko biyu a cikin extrusion na gargajiya, larurar isassun hadawa a cikin haɗaɗɗun extrusion yana sa tagwayen-dunƙule extruders duka amma dole ne.

NAU'O'IN FARUWA
Akwai sub-iri biyu na tagwaye dunƙule extruders: co-juyawa da counter-juyawa. Wannan nomenclature yana nufin kusancin inda kowane dunƙule ke juyawa idan aka kwatanta da ɗayan. A yanayin jujjuyawar haɗin gwiwa, sukulan biyu suna jujjuya ko dai a kusa da agogo ko kuma a kan agogo; a counter-juyawa, dunƙule ɗaya yana jujjuya agogon agogo yayin da ɗayan yana jujjuya agogon agogo baya. An nuna cewa, don wani yanki na giciye da aka ba da shi da digiri na zoba (intermeshing), saurin axial da digiri na haɗuwa ya fi girma a cikin masu fitar da tagwaye masu juyawa. Duk da haka, haɓakar matsa lamba ya fi girma a cikin masu juyawa masu juyawa. Zane-zanen dunƙule ya zama na yau da kullun a cikin cewa ana shirya abubuwa daban-daban na isar da abubuwa masu haɗawa a kan ramukan don ba da izinin sake daidaitawa cikin sauri don canjin tsari ko maye gurbin abubuwan kowane mutum saboda lalacewa ko lalacewa. Girman injin ɗin yana daga ƙanana kamar 12 mm zuwa babba kamar 380mm

AMFANIN
Babban amfani da extrusion shine cewa bayanan martaba irin su bututu ana iya yin su zuwa kowane tsayi. Idan kayan yana da isasshen sassauƙa, ana iya yin bututu a tsayi mai tsayi har ma da murɗawa a kan reel. Wani fa'ida shine extrusion na bututu tare da haɗakar ma'aurata gami da hatimin roba.