Malo osungunuka a crystallization a PTFE ndi 327 ℃, koma utomoni sungathe kukhala wosungunuka mpaka utakhala pamwamba pa 380 ℃, ndipo kusungunuka kwa viscosity ndikokwera kwambiri 1 010 Pa * S.Komanso, PTFE ali wamphamvu zosungunulira kukana.Choncho, sangathe kusungunula njira processing, sangathe kusungunuka processing njira, kawirikawiri kupanga mankhwala ake akhoza kukhala ngati zitsulo ndi ceramic processing - chitsanzo, choyamba ufa compaction, ndiye sintering ndi makina processing, kapena kudzera extrusion akamaumba, isotactic kukanikiza. kuumba, ❖ kuyanika akamaumba ndi calendering akamaumba ndi njira zina processing.
Malo osungunuka a crystallization a PTFE ndi 327 ℃, koma utomoni sungathe kukhala wosungunuka mpaka utakhala pamwamba pa 380 ℃, ndipo kusungunuka kwa viscosity ndikokwera kwambiri 1 010 Pa * S.Komanso, PTFE ali wamphamvu zosungunulira kukana.Choncho, sangathe kusungunula njira processing, sangathe kusungunuka processing njira, kawirikawiri kupanga mankhwala ake akhoza kukhala ngati zitsulo ndi ceramic processing - chitsanzo, choyamba ufa compaction, ndiye sintering ndi makina processing, kapena kudzera extrusion akamaumba, isotactic kukanikiza. kuumba, ❖ kuyanika akamaumba ndi calendering akamaumba ndi njira zina processing.
1. Kuumba
Akamaumba pakali pano ambiri ntchito akamaumba njira kwa PTFE.Kuumba lusondi zina akamaumba zipangizo (ufa, granule, fibrous zakuthupi, etc.) mu nkhungu zitsulo, mu - - fixed kutentha, kuthamanga - - njira kupanga.Ma polima opangidwa sakhala ochepa ndi kulemera kwawo kwa maselo, ndipo pafupifupi mapulasitiki onse amatha kupangidwa.Mbali zazikulu za kuumba ndi;Mtengo wotsika, zida zosavuta, ndalama zochepa, osati zochepa ndi kulemera kwa maselo a mapulasitiki okonzedwa;Zoyipa zake ndizochepa zopanga, kuchuluka kwantchito komanso kusakhazikika kwazinthu.PTFE ndi yolemera kwambiri ya mamolekyulu komanso kusayenda bwino kwamadzi.Pamene njira zina processing si okhwima, PTFE mankhwala makamaka kukonzedwa ndi akamaumba padziko lonse lapansi.
Mu akamaumba akhoza kugawidwa m'njira zisanu malinga ndi kusiyana kwa ndondomeko yeniyeni: (1) kukanikiza - kukanikiza njira (yotchedwanso free sintering njira); (2) sintering - kukanikiza njira; (3) kutenthetsa mofulumira kukanikiza. njira;(5) kukanikiza munthawi yomweyo ndi sintering njira.
2. Njira ya Hydroform
Hydraulic pressure njira, yomwe imadziwikanso kuti njira yofananira, njira ya kuthamanga kwa isobaric kapena njira yopangira mphira, ndikuwonjezera PTFE utomoni wogawana pakati pa thumba ndi khoma la nkhungu, kenako ku thumba mumadzi (madzi omwe amagwiritsidwa ntchito nthawi zambiri), kupanikizika kwa thumba mphira kuti nkhungu kukulitsa khoma, compacting utomoni ndi kukhala preformed mankhwala - njira.Njirayi ingagwiritsidwe ntchito popanga manja akuluakulu, pansi posungira pansi, chipolopolo cha hemispheric, nsanja ya nsanja, slab yaikulu, ndi zina zotero, komanso zinthu zovuta zomwe zimakhala ndi PTFE, monga tee, chigongono ndi mbiri.Ubwino waukulu wa kuumba kwa hydraulic ndi mawonekedwe osavuta a zida ndi nkhungu - mpope wamadzi wamba umalowa m'malo mwa makina osindikizira a tonnage, ndipo zinthuzo zimapanikizidwa mofanana komanso mwamphamvu - zomwe zimapangitsa kupanga zigawo zazikulu, mawonekedwe ovuta komanso mawonekedwe osavuta. .
3. Kankhani akamaumba
Push pressure imadziwikanso kuti phala extrusion molding, 20-30 mesh sieve of disperse resin and organic additives (toluene, petroleum etha, zosungunulira mafuta, chiŵerengero cha utomoni wolemera 1/5) wothira phala, prepress mu wandiweyani khoma cylindrical opanda kanthu. , ndiye ikani mu mbiya ya makina osindikizira, pansi pa kutentha ndi kuumba kwa plunker.Mukaumitsa ndi kuzizira pa kutentha kwa 360 ~ 380 ° C, kukankhira mwamphamvu ndi kolimba ndi kukakamiza chubu ndi zinthu za bar zimapezedwa pambuyo pozizira.Zinthu zokankhira ndi kukanikiza zimangokhala ndodo yokhala ndi mainchesi a 16mm kapena kuchepera ndi chitoliro chokhala ndi khoma la 3mm kapena kuchepera.
4. Spiral extrusion akamaumba
The screw extruder ya PTFE ufa ndi yosiyana ndi extruder yogwiritsidwa ntchito ndi mapulasitiki ena a thermoplastic.The extrusion akamaumba wamba thermoplastic mapulasitiki ndi kukankhira zinthu patsogolo mothandizidwa ndi wononga kasinthasintha, ndipo panthawiyi compress, kukameta ubweya ndi kusakaniza zakuthupi.Zinthuzi zimasungunukanso ndi kutentha komwe kumapangidwa ndi mphamvu ya shear komanso kutentha kwakunja kwa silinda yazinthu.Komabe, screw ya PTFE extruder imangogwira ntchito yotumiza ndikukankhira, kotero kuti zinthuzo zimadutsa pamutu wa chotupa chimodzi chokhala ndi ulusi wamutu wawiri ndi phula lomwelo ndi kuya, kenako ndikulowa mkamwa mwa nkhungu. sintering ndi kuziziritsa, ndi mafomu ndi kukakamizidwa kuperekedwa ndi chipangizo chotsutsa-pressure kukwaniritsa cholinga mosalekeza.Nthawi zambiri zimakhala zovuta pokonza PTFE ndi single screw extruder.Kutsika kwamphamvu kwa PTFE ufa kumayambitsa skidding panthawi yodyetsa, zomwe zimachepetsa kwambiri mphamvu yotumizira wononga.Ndipo chifukwa cha kutentha kwa mkangano, kungapangitsenso kumatira kwa ufa ku wononga kapena mbiya, kupangitsa kudyetsa kukhala kovuta komanso kosakhazikika.
M'zaka zaposachedwapa, mapasa-screw amagwiritsidwanso ntchito pokonza zipangizo zamtunduwu wapadera.Mfundo yake yodyetsera ndi yosiyana ndi ya single-screw extruder, ndipo imakhala ndi ntchito yabwino yoyendera, yomwe imatha kuthana ndi vuto lotsetsereka la ufa wa UHMWPE mu screw ndikuwongolera kwambiri mphamvu yodyetsa ya screw.The potsutsa-azungulira amapasa screw extruder ali bwino kusanganikirana ndi homogenization zotsatira kuposa yemweyo malangizo amapasa screw extruder, koma chifukwa cha mphamvu yake yaikulu kulekana, kumeta ubweya kanthu pa kusiyana kwa wononga ndi lalikulu, zomwe zimapangitsa zinthu kutenthedwa. , ndipo kulemera kwa maselo a extruder kumatha kutsika pafupifupi 40%.Ngati kusiyana kuli kwakukulu ndipo wononga sichikuphatikizidwa, zinthuzo zimamatira kuzitsulo zotentha.Komabe, ntchito kasinthasintha yemweyo wa amapasa wononga extruder, palibe vuto.Zofunika mu extruder ndi akumeta ubweya kanthu ang'onoang'ono, plasticizing chofunika kuchuluka kwa kutentha, onse kuchokera kuphatikiza kutentha gwero, ndipo potero akhoza kulamulira yeniyeni, zimene zingachititse zinthu mu ndondomeko extrusion kuchepetsa kuwonongeka kutentha, pa nthawi yomweyo mu kuti apitirize kuyenda bwino ndi okhazikika mphuno, gawo la mphuno kukula kwa kapangidwe ayenera n'zogwirizana ndi buku la wononga wononga zinthu.Kuthamanga kwa screw sikothamanga, nthawi zambiri kumakhala kuzungulira 10 pamphindi.Pofuna kupewa zinthu mwadzidzidzi kumamatira pamwamba zitsulo, kutentha kwa extrusion kuyenera kuyendetsedwa mosamalitsa.
5. Plunger extrusion akamaumba
Plunger extrusion processing pulasitiki, pulasitiki processing ndi njira yakale, kuyambira zikamera wa nkhaniyi, anthu anayamba kugwiritsa ntchito njira imeneyi pokonza pulasitiki.PTFE imakonzedwa ndi plunger extruder mwa kukanikiza utomoni wochulukira mu nkhungu yolowera, kupangitsa plunger kubwereza ndikukankhira kukhala chinthu chopangidwa kale.Choncho mmbuyo ndi mtsogolo, mkamwa nkhungu kupanga Mipikisano - siteji chisanadze - akamaumba mankhwala.Chifukwa cha kukangana pakati PTFE utomoni ndi kukangana pakati PTFE utomoni ndi nkhungu khoma, ndi voliyumu kukula kwa mankhwala preformed pa sintering mu nkhungu, mankhwala preformed ndi sintered ndi utakhazikika mu mosalekeza lonse pansi pa mavuto.Ubwino wa njirayi ndi motere: palibe kumeta ubweya komwe kumachitika poumba, kulemera kwa maselo kumachepa, khalidwe la mankhwala ndi labwino, ndipo silimangokhala ndi kulemera kwa maselo.Komabe, chifukwa cha malo ang'onoang'ono kukhudzana pakati pa zipangizo ndi kutentha mbali mu ndondomeko extrusion, Kutentha dzuwa ndi otsika, amene amachepetsa extrusion liwiro.
6. Njira zina zopangira;
PTFE amathanso kukonzedwa ndi jekeseni akamaumba, calendering akamaumba, ❖ kuyanika akamaumba kapena yachiwiri akamaumba.
Nthawi yotumiza: Jul-31-2018