Xyuas kom qhuav
Nylon yog hygroscopic ntau dua, yog tias raug huab cua ntev ntev, yuav nqus dej noo hauv huab cua.Ntawm qhov kub siab tshaj qhov melting point (kwv yees 254 ° C), dej molecules reacts chemically nrog nylon.Cov tshuaj tiv thaiv no, hu ua hydrolysis lossis cleavage, oxidizes nylon thiab discolors nws.Qhov hnyav molecular thiab toughness ntawm cov resin kuj tsis muaj zog, thiab cov fluidity yog nce.Cov dej noo absorbed los ntawm cov yas thiab cov roj tawg tawm ntawm qhov sib koom ua ke clamping qhov chaw, lub teeb yog tsim rau ntawm qhov chaw yog tsis du, nyiaj grain, speckle, microspores, npuas, hnyav yaj expansion tsis tuaj yeem tsim los yog tsim tom qab txhua yam muaj zog poob qis.Thaum kawg, cov nylon cleaved los ntawm no hydrolysis yog kiag li irreducible thiab tsis tuaj yeem siv dua txawm tias nws rov qhuav.
Cov khoom siv nylon ua ntej txhaj tshuaj molding kom qhuav yuav tsum tau ua kom tiav, kom qhuav mus rau qib twg los ntawm cov kev xav tau ntawm cov khoom tiav los txiav txim siab, feem ntau 0.25% hauv qab no, zoo dua tsis pub tshaj 0.1%, tsuav yog cov khoom siv raw qhuav zoo, txhaj tshuaj molding yog yooj yim, qhov chaw yuav tsis coj teeb meem ntau ntawm qhov zoo.
Nylon tau zoo siv lub tshuab nqus tsev ziab kom zoo, vim tias qhov kub thiab txias ntawm atmospheric siab ziab yog siab dua, cov khoom siv raw kom qhuav tseem muaj kev sib cuag nrog oxygen hauv huab cua thiab muaj peev xwm ntawm oxidation discoloration, ntau oxidation kuj tseem muaj qhov cuam tshuam, yog li uas zus tau tej cov brittle.
Thaum tsis muaj cov cuab yeej siv tshuab ziab khaub ncaws, huab cua kom qhuav tsuas yog siv tau, txawm tias cov nyhuv tsis zoo.Muaj ntau ntau cov ntsiab lus sib txawv rau atmospheric ziab khaub ncaws, tab sis ntawm no tsuas yog ob peb yam.Thawj yog 60 ℃ ~ 70 ℃, cov khoom txheej thickness 20 hli, ci 24h ~ 30h;Qhov thib ob tsis ntau tshaj 10h thaum ziab hauv qab 90 ℃;Qhov thib peb yog nyob rau ntawm 93 ℃ lossis qis dua, ziab 2h ~ 3h, vim tias nyob rau hauv huab cua kub ntau tshaj 93 ℃ thiab txuas ntxiv 3h saum toj no, nws muaj peev xwm ua rau nylon xim hloov, yog li qhov kub thiab txias yuav tsum tau txo mus rau 79 ℃;Qhov thib plaub yog ua kom qhov kub thiab txias mus rau ntau tshaj 100 ℃, lossis txawm tias 150 ℃, vim qhov kev xav ntawm cov nylon raug rau huab cua ntev dhau los lossis vim kev ua haujlwm tsis zoo ntawm cov khoom ziab;Qhov thib tsib yog kev txhaj tshuaj molding tshuab kub cua hopper kom qhuav, qhov kub ntawm cov cua kub rau hauv lub hopper yog tsa kom tsis pub tsawg tshaj 100 ℃ lossis siab dua, kom cov dej noo hauv cov yas evaporates.Tom qab ntawd cov cua kub yog muab tshem tawm raws li saum toj ntawm lub hopper.
Yog hais tias cov yas qhuav tau nthuav tawm hauv huab cua, nws yuav nqus dej sai sai hauv cov huab cua thiab poob cov nyhuv ziab.Txawm tias nyob rau hauv lub tshuab hopper npog, lub sij hawm cia yuav tsum tsis txhob ntev heev, feem ntau tsis ntau tshaj 1 teev nyob rau hauv rainy hnub, tshav ntuj hnub yog txwv rau 3 teev.
Tswj lub chim kub
Nylon melting kub yog siab, tab sis thaum mus txog qhov melting point, nws viscosity qis dua li cov thermoplastics xws li polystyrene, yog li ua fluidity tsis yog ib qho teeb meem.Tsis tas li ntawd, vim muaj cov khoom siv rheological ntawm nylon, qhov pom tseeb viscosity txo qis thaum shear npaum li cas nce, thiab cov melting kub ntau yog nqaim, nruab nrab ntawm 3 ℃ thiab 5 ℃, yog li cov khoom siv kub yog qhov lav ntawm cov pwm puv.
Tab sis nylon nyob rau hauv lub xeev melting thaum lub thermal stability tsis zoo, kev ua cov khoom siab dhau heev lawm lub sij hawm cua sov yuav ua rau lub polymer degradation, yog li ntawd cov khoom tshwm npuas, lub zog poob.Yog li ntawd, qhov kub ntawm txhua ntu ntawm lub thoob yuav tsum tau tswj nruj me ntsis, kom cov pellet nyob rau hauv lub siab melting kub, qhov cua sov qhov teeb meem yog tsim nyog raws li qhov tsim nyog, ib co niaj hnub, kom tsis txhob phem melting thiab lub zos overheating tshwm sim.Raws li rau tag nrho molding, qhov kub ntawm lub thoob yuav tsum tsis txhob ntau tshaj 300 ℃, thiab lub sij hawm cua sov ntawm lub pellet nyob rau hauv lub chim yuav tsum tsis txhob ntau tshaj 30min.
Txhim kho cov khoom siv
Thawj yog qhov xwm txheej hauv lub thoob, txawm hais tias muaj ntau cov khoom siv rau pem hauv ntej txhaj tshuaj, tab sis qhov rov qab ntws ntawm cov khoom siv molten nyob rau hauv cov ntsia hlau zawj thiab to ntawm lub ntsej muag kawg ntawm cov ntsia hlau thiab sab hauv phab ntsa ntawm inclined chim kuj nce. vim tias cov kua dej loj, uas tsis yog tsuas yog txo cov kev txhaj tshuaj zoo thiab cov khoom noj, tab sis kuj qee zaum cuam tshuam qhov kev vam meej ntawm kev pub noj, kom cov ntsia hlau tsis tuaj yeem rov qab.Yog li ntawd, lub voj voog yuav tsum tau muab ntsia rau pem hauv ntej ntawm lub thoob kom tsis txhob rov qab los.Tab sis tom qab txhim kho lub nplhaib kos, cov khoom siv kub yuav tsum tau nce los ntawm 10 ℃ ~ 20 ℃ raws li, kom lub siab poob tuaj yeem them rov qab.
Qhov thib ob yog lub nozzle, kev txhaj tshuaj tiav, lub hau ntswj rov qab, lub molten nyob rau hauv pem hauv ntej lub cub tawg nyob rau hauv seem seem yuav ntws tawm ntawm lub nozzle, uas yog, lub thiaj li hu ua "salivation phenomenon".Yog hais tias cov khoom yuav tsum tau salivated rau hauv cov kab noj hniav yuav ua rau qhov chaw nrog cov khoom txias me ntsis los yog nyuaj rau sau, yog hais tias lub nozzle tiv thaiv pwm ua ntej tshem tawm, thiab zoo heev ua rau lub lag luam ntawm cov teeb meem, kev lag luam tsis raug nqi.Nws yog ib txoj hauv kev zoo los tswj qhov kub ntawm lub nozzle los ntawm kev teeb tsa lub nplhaib hloov kho cua sov ntawm lub nozzle, tab sis cov txheej txheem tseem ceeb yog hloov lub nozzle nrog lub caij nplooj ntoos hlav-lub qhov valve nozzle.Tau kawg, cov khoom siv caij nplooj ntoos hlav siv los ntawm hom nozzle yuav tsum tiv taus qhov kub thiab txias, txwv tsis pub nws yuav poob nws cov nyhuv elastic vim rov ua compression annealing ntawm qhov kub thiab txias.
Xyuas kom lub cev tuag thiab tswj qhov kub thiab txias
Vim hais tias ntawm qhov siab melting point ntawm nylon, nyob rau hauv lem, nws lub freezing point kuj yog siab, cov khoom melting rau hauv cov pwm txias tuaj yeem ua kom ruaj khov txhua lub sijhawm vim qhov kub thiab txias kom poob qis dua qhov melting point, tiv thaiv kev ua tiav ntawm pwm filling. , yog li kev txhaj tshuaj high-speed yuav tsum tau siv, tshwj xeeb tshaj yog rau nyias-walled qhov chaw lossis qhov chaw nyob ntev.Tsis tas li ntawd, kev kub ceev pwm filling kuj coj cov kab noj hniav tawm teeb meem, nylon pwm yuav tsum muaj kev ntsuas kom txaus.
Nylon muaj qhov yuav tsum tau muaj qhov kub thiab txias ntau dua li cov thermoplastics.Feem ntau hais lus, pwm kub kub yog qhov zoo rau kev ntws.Nws yog ib qho tseem ceeb heev rau qhov complex.Qhov teeb meem yog tias cov yaj txias txias tom qab sau cov kab noj hniav muaj qhov cuam tshuam loj rau cov qauv thiab cov khoom ntawm nylon daim.Feem ntau yog nyob rau hauv nws cov crystallization, thaum nws nyob rau hauv lub kub kub nyob rau hauv ib tug amorphous lub xeev mus rau hauv cov kab noj hniav, crystallization pib, qhov luaj li cas ntawm crystallization tus nqi yog nyob rau hauv lub siab thiab qis pwm kub thiab kub hloov pauv tus nqi.Thaum cov khoom nyias nyias nrog siab elongation, zoo transparency thiab toughness yuav tsum tau, lub pwm kub yuav tsum tau qis kom txo cov degree ntawm crystallization.Thaum lub phab ntsa tuab nrog lub siab hardness, zoo hnav tsis kam thiab me me deformation nyob rau hauv kev siv yog yuav tsum tau, lub pwm kub yuav tsum tau siab dua los mus nce qib ntawm crystallization.Nylon pwm kub yuav tsum tau siab dua, qhov no yog vim nws txoj kev shrinkage tus nqi yog loj, thaum nws hloov los ntawm molten lub xeev mus rau lub xeev cov khoom ntim shrinkage loj heev, tshwj xeeb tshaj yog rau cov khoom phab ntsa tuab, pwm kub tsawg dhau yuav ua rau sab hauv.Tsuas yog thaum pwm kub tswj tau zoo tuaj yeem ua qhov loj ntawm qhov chaw ruaj khov.
Qhov ntsuas kub ntawm cov nylon pwm yog 20 ℃ ~ 90 ℃.Nws yog qhov zoo tshaj kom muaj ob qho tib si txias (xws li kais dej) thiab cua sov (xws li plug-in electric heating rod) ntaus ntawv.
Annealing thiab humidification
Rau kev siv kub siab tshaj 80 ℃ los yog nruj precision yuav tsum tau ntawm cov khoom, tom qab molding yuav tsum tau annealed nyob rau hauv roj los yog paraffin.Lub annealing kub yuav tsum yog 10 ℃ ~ 20 ℃ siab tshaj qhov kev pabcuam kub, thiab lub sijhawm yuav tsum yog li 10min ~ 60min raws li qhov tuab.Tom qab annealing, nws yuav tsum tau txias maj mam.Tom qab annealing thiab kev kho cua sov, cov nylon siv lead ua loj tuaj yeem tau txais, thiab cov rigidity tau zoo tuaj.Crystallized qhov chaw, qhov hloov ceev yog me me, tsis deformation thiab tawg.Cov khoom kho los ntawm txoj kev txias txias tam sim no muaj crystallinity tsawg, siv lead ua me me, siab toughness thiab pob tshab.
Ntxiv nucleating tus neeg sawv cev ntawm nylon, kev txhaj tshuaj molding tuaj yeem tsim cov crystallinity loj, tuaj yeem ua rau lub voj voog txhaj tshuaj, qhov pom tseeb thiab rigidity ntawm cov khoom tau txhim kho.
Kev hloov ntawm cov av noo nyob ib puag ncig tuaj yeem hloov qhov loj ntawm nylon daim.Nylon nws tus kheej shrinkage tus nqi siab dua, txhawm rau tswj qhov zoo tshaj plaws kuj ruaj khov, tuaj yeem siv dej los yog cov tshuaj aqueous los tsim kev kho ntub dej.Cov txheej txheem yog tsau rau hauv cov dej kub npau npau lossis potassium acetate aqueous tov (qhov piv ntawm cov poov tshuaj acetate thiab dej yog 1.25: 100, boiling point 121 ℃), lub sij hawm soaking nyob ntawm lub siab tshaj plaws phab ntsa thickness ntawm cov khoom, 1.5 hli 2h. 3mm 8h, 6mm 16h.Kev kho av humidification tuaj yeem txhim kho cov qauv siv lead ua ntawm cov yas, txhim kho qhov toughness ntawm qhov chaw, thiab txhim kho kev faib tawm ntawm kev ntxhov siab sab hauv, thiab cov nyhuv zoo dua li kev kho annealing.
Post lub sij hawm: 03-11-22