Deformation ntawm txhaj tshuaj molded khoom
Deformation yog ib qho tsis xws luag hauv kev txhaj tshuaj molding ntawm nyias-plhaub yas qhov chaw, vim hais tias nws muaj kev kwv yees tseeb ntawm warpage deformation, thiab warpage deformation txoj cai ntawm kev txhaj tshuaj molded qhov chaw ntawm cov khoom sib txawv thiab cov duab sib txawv heev. Thaum tus nqi ntawm warpage ntau tshaj qhov tso cai yuam kev, nws dhau los ua qhov tsis xws luag, uas cuam tshuam rau cov khoom sib dhos.
Kev kwv yees tseeb ntawm warpage deformation ntawm ntau qhov ntau ntawm cov phab ntsa nyias nyias (phab ntsa thickness tsawg dua 2 hli) yog qhov yuav tsum tau ua ua ntej rau kev tswj tau zoo ntawm warpage defects. Warpage deformation tsom xam feem ntau txais kev soj ntsuam zoo, thiab kev ntsuas yog coj los ntawm cov khoom tsim, pwm tsim thiab kev txhaj tshuaj molding txheej txheem kom tsis txhob loj warpage deformation ntau li ntau tau.
Ua rau Analysis
Pwm
Txoj hauj lwm, daim ntawv thiab tus naj npawb ntawm cov rooj vag ntawm lub qhov rooj txhaj tshuaj pwm yuav cuam tshuam rau lub xeev filling ntawm cov yas hauv pwm kab noj hniav, uas ua rau deformation ntawm cov yas.
Qhov ntev ntawm qhov khiav deb, qhov ntau dua qhov kev ntxhov siab sab hauv los ntawm kev khiav thiab kev pub mis ntawm cov txheej khov thiab cov txheej hauv nruab nrab; ntawm qhov tsis sib xws, qhov luv ntawm qhov ntws deb, lub sijhawm luv dua ntawm lub rooj vag mus rau qhov kawg ntawm qhov ntws, thiab cov pwm yuav khov thaum sau lub thickness ntawm txheej yog thinned, qhov kev ntxhov siab sab hauv yog txo, thiab warping. deformation kuj txo qis heev. Yog tias tsuas yog ib lub rooj vag nruab nrab lossis ib lub rooj vag ib sab yog siv, cov yas molded yuav raug distorted vim hais tias lub shrinkage tus nqi nyob rau hauv txoj kab uas hla yog ntau dua li nyob rau hauv lub circumferential kev taw qhia; Yog tias siv ntau lub rooj vag taw tes hloov, nws tuaj yeem tiv thaiv warping thiab deformation.
Thaum qhov chaw casting yog siv rau molding, kuj yog vim lub anisotropy ntawm yas shrinkage, txoj hauj lwm thiab tus naj npawb ntawm cov rooj vag muaj kev cuam tshuam zoo rau cov degree ntawm deformation ntawm yas qhov chaw. Vim tias 30 feem pua cov iav fiber reinforced PA6 yog siv, qhov tau txais yog Ib qho loj txhaj tshuaj molded nrog qhov hnyav ntawm 4.95kg, yog li muaj ntau cov hlua txuas ntxiv raws li cov kev taw qhia ntawm cov phab ntsa ib puag ncig, kom txhua lub rooj vag tuaj yeem sib npaug.
Tsis tas li ntawd, kev siv ntau lub rooj vag tuaj yeem ua kom luv luv ntawm cov yas ntws piv (L / t), kom cov khoom ntom ntom hauv cov pwm kab noj hniav yog qhov sib xws thiab qhov shrinkage ntau dua. Nyob rau tib lub sijhawm, tag nrho cov khoom yas tuaj yeem muab ntim rau hauv ib qho kev txhaj tshuaj me me. Kev txhaj tshuaj qis dua tuaj yeem txo qhov kev xav ntawm molecular kev nyiam ntawm cov yas thiab txo nws cov kev ntxhov siab sab hauv, yog li txo qhov deformation ntawm cov khoom yas.
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Pwm kub: Cov pwm kub muaj qhov cuam tshuam zoo rau kev ua haujlwm sab hauv thiab pom zoo ntawm cov khoom. Qhov kub ntawm cov pwm nyob ntawm qhov muaj lossis tsis muaj cov yas crystallinity, qhov loj thiab cov qauv ntawm cov khoom, cov kev xav tau ntawm kev ua haujlwm, thiab lwm yam txheej txheem (kua kub, kev txhaj tshuaj ceev thiab txhaj tshuaj, lub voj voog molding, thiab lwm yam).
Kev tswj lub siab: Lub siab nyob rau hauv cov txheej txheem txhaj tshuaj molding muaj xws li plasticizing siab thiab txhaj tshuaj, thiab ncaj qha cuam tshuam rau plasticizing plastics thiab cov khoom zoo.
Kev siv cov txheej txheem kev sim los kawm txog kev ua tsov rog ntawm cov khoom yas yog qhov tseem ceeb hauv kev tshawb fawb txog qhov cuam tshuam ntawm cov khoom siv, cov khoom geometry thiab qhov loj me, thiab cov txheej txheem txhaj tshuaj molding ntawm cov khoom warpage. Muaj ntau qhov kev sim tau tsim los kom tau txais kev cuam tshuam ntawm lub rooj vag geometry, ntim cov khoom (tuav siab thiab tuav lub sijhawm) thiab pwm elasticity ntawm qhov kawg ntawm cov khoom.
PET tau siv los ua lub hauv paus polymer, thiab cov yam ntxwv ntawm warpage ntawm cov khoom sib txawv thiab cov phab ntsa thickness sib txawv tau kawm. Qhov kev sib raug zoo ntawm qhov sib piv ntawm 33 feem pua pob tshab iav-txhim kho fiber ntau PA66 txhaj tshuaj molded disk, anisotropy ntawm linear thermal expansion coefficient, lub thickness ntawm cov khoom thiab cov warpage tau sim kawm, thiab lub tswv yim ntawm warpage index tau npaj thawj zaug. . Warpage yam ntxwv, thiab kev sib raug zoo ntawm warpage index, warpage thiab fiber orientation xeev, thiab kev sib raug zoo ntawm yield thiab warpage index tau kawm.
Txoj kev sim los kawm txog warpage deformation feem ntau txwv rau cov duab geometric tshwj xeeb, cov khoom siv tshwj xeeb thiab cov txheej txheem txheej txheem, thiab tsis tuaj yeem xav txog kev cuam tshuam ntawm ntau yam ntawm warpage deformation, thiab tsis tuaj yeem kwv yees ua tau warpage thaum lub sij hawm tsim khoom. Qhov loj ntawm qhov deformation. Hauv kev siv tiag tiag, cov kev txwv ntawm cov qauv empirical kuj pom tseeb, tsis tsuas yog cuam tshuam los ntawm kev sim cov xwm txheej, tab sis kuj muaj feem xyuam rau ntau yam xws li kev ua cov txheej txheem ntawm cov ntaub ntawv sim thiab daim ntawv thov cov xwm txheej ntawm cov qauv empirical, thiab cov qauv empirical. tsuas yog tsim nyog rau qhov kev sim. ze rau cov txheej txheem ntau lawm.
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shrink / warp
Txij li thaum warping deformation muaj feem xyuam rau qhov tsis sib xws ntawm shrinkage, kev sib raug zoo ntawm shrinkage thiab cov khoom warpage yog soj ntsuam los ntawm kev kawm cov shrinkage cwj pwm ntawm cov yas sib txawv nyob rau hauv cov txheej txheem sib txawv. Nyob rau hauv lub hauv paus ntawm kev txhaj tshuaj molding txaus, tuav lub siab thiab txias simulation, los ntawm kev sim thiab linear regression txoj kev, ib tug qauv rau kwv yees lub shrinkage ntawm txhaj tshuaj molded khoom yog npaj. Nyob rau hauv lub hauv paus ntawm shrinkage kwv yees, lub deformation ntawm cov khoom yog xam los ntawm cov qauv kev soj ntsuam simulation cov kev pab cuam.
Nws yog qhov nyuaj kom tau txais cov khoom lag luam nrog qhov tseeb qhov tseeb nrog cov ntaub ntawv nrog qhov siab shrinkage. Yuav kom siv zog rau siab precision, amorphous resins thiab resins nrog zoo ib yam shrinkage nyob rau hauv tag nrho cov lus qhia yuav tsum tau siv ntau li ntau tau. Rau ntau cov ntaub ntawv, lub shrinkage ntawm cov khoom yog ntsuas nyob rau hauv cov kev mob ntawm kev hloov lub ndlwg tus nqi, tuav siab, tuav lub sij hawm, pwm kub, filling lub sij hawm, khoom thickness thiab lwm yam tsis.
Raws li kev ntsuam xyuas, qhov shrinkage ntawm cov khoom yog muab faib ua peb ntu: ntim shrinkage, uneven shrinkage tshwm sim los ntawm molecular orientation, thiab uneven shrinkage tshwm sim los ntawm unbalanced txias. Shrinkage kwv yees txoj kev rau volumetric shrinkage, crystalline cov ntsiab lus, pwm confinement, yas orientation, thiab lwm yam., siv ndlwg thiab txias tsom xam los kwv yees shrinkage hom.
Txias System Design
Thaum lub sij hawm kev txhaj tshuaj, qhov tsis sib npaug ntawm qhov txias ntawm cov yas yuav ua rau qhov tsis sib xws ntawm cov khoom yas. Qhov sib txawv ntawm shrinkage no yuav ua rau lub cim ntawm bending lub sij hawm thiab warp ntawm cov yas ib feem.
Yog tias qhov kub ntawm qhov sib txawv ntawm cov pwm kab noj hniav thiab cov tub ntxhais siv hauv kev txhaj tshuaj molding tiaj tus yas qhov chaw loj dhau lawm, cov yaj nyob ze rau ntawm cov pwm kab noj hniav yuav txias sai sai, thaum cov khoom txheej ze rau ntawm qhov kub pwm kab noj hniav. yuav txuas ntxiv mus, qhov tsis sib xws shrinkage yuav warp cov yas. Yog li ntawd, qhov txias ntawm cov pwm txhaj tshuaj yuav tsum tau them sai sai rau qhov kub ntawm qhov sib npaug ntawm cov kab noj hniav thiab cov tub ntxhais, thiab qhov kub ntawm qhov sib txawv ntawm ob yuav tsum tsis txhob loj heev.
Ntxiv nrog rau kev txiav txim siab tias qhov kub thiab txias ntawm sab hauv thiab sab nrauv ntawm cov yas feem ntau sib npaug, qhov kub ntawm txhua sab ntawm cov yas yuav tsum tau txiav txim siab kom zoo ib yam, uas yog, thaum pwm txias, sim ua. Ua kom qhov kub thiab txias ntawm cov kab noj hniav thiab cov tub ntxhais tsis sib xws thoob plaws, kom qhov txias ceev ntawm cov yas sib npaug, kom lub shrinkage yog ntau uniform nyob txhua qhov chaw, zoo tiv thaiv deformation. Yog li ntawd, kev npaj cov dej txias qhov ntawm cov pwm yog qhov tseem ceeb heev. Tom qab qhov kev ncua deb ntawm cov yeeb nkab phab ntsa mus rau saum npoo ntawm cov kab noj hniav tau txiav txim siab, qhov kev ncua deb ntawm cov dej txias qhov dej yuav tsum yog me me li sai tau los xyuas kom meej tias qhov kub ntawm cov kab noj hniav ntawm phab ntsa yog uniform.
Nyob rau tib lub sijhawm, txij li qhov kub ntawm qhov nruab nrab cua txias nce nrog qhov nce ntawm qhov ntev ntawm cov dej txias channel, cov kab noj hniav thiab cov tub ntxhais ntawm cov pwm yuav muaj qhov kub thiab txias sib txawv raws cov dej channel. Yog li ntawd, cov dej channel ntev ntawm txhua qhov cua txias yuav tsum tsawg dua 2m. Ob peb lub tshuab cua txias yuav tsum tau teeb tsa hauv cov pwm loj, thiab qhov nkag ntawm ib lub voj voog nyob ze ntawm lub qhov hluav taws xob ntawm lwm qhov hluav taws xob. Rau qhov ntev ntawm cov yas, yuav tsum tau siv lub tshuab ua kom txias kom txo tau qhov ntev ntawm lub tshuab cua txias, uas yog, kom txo qhov kub ntawm qhov sib txawv ntawm pwm, thiaj li ua kom qhov sib txawv ntawm cov khoom yas.
Tus tsim ntawm lub ejection system kuj ncaj qha cuam tshuam rau deformation ntawm cov yas ib feem. Yog hais tias lub layout ntawm lub ejection system yog unbalanced, nws yuav ua rau ib tug imbalance nyob rau hauv lub ejection quab yuam thiab deform lub yas ib feem. Yog li ntawd, thaum tsim lub ejection system, nws yuav tsum siv zog sib npaug nrog lub demoulding kuj.
Tsis tas li ntawd, qhov chaw hla ntawm lub ejector pas nrig yuav tsum tsis txhob me dhau los tiv thaiv cov yas los ntawm kev deformed vim muaj zog ntau dhau ntawm ib cheeb tsam (tshwj xeeb tshaj yog thaum lub demoulding kub siab dhau). Lub ejector tus pin yuav tsum tau teem kom ze li sai tau rau qhov uas muaj qhov loj tshaj plaws demoulding tsis kam. Raws li qhov kev pom zoo tsis cuam tshuam rau qhov zoo ntawm cov khoom yas (nrog rau kev siv cov kev xav tau, qhov tseeb qhov tseeb thiab cov tsos, thiab lwm yam), yuav tsum tau nruab ntau lub ejector pins raws li qhov ua tau kom txo tau tag nrho cov deformation ntawm cov khoom yas.
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Thaum cov yas mos yog siv los tsim cov kab sib sib zog nqus loj thiab nyias-walled yas qhov chaw, vim yog qhov siab demoulding tsis kam thiab cov khoom muag muag, yog tias ib qho kev siv tshuab ejection tau txais tag nrho, cov khoom yas yuav deformed los yog txawm thawb los ntawm. Los yog cov yas yuav raug muab pov tseg vim yog folding. Nws yuav zoo dua los siv ntau cov khoom sib xyaw ua ke lossis kev sib xyaw ua ke ntawm cov pa roj (hydraulic) siab thiab cov tshuab ejection.
Kev cuam tshuam ntawm Residual Thermal Stress ntawm Warping thiab Deformation ntawm cov khoom
Nyob rau hauv cov txheej txheem txhaj tshuaj molding, residual thermal stress yog ib qho tseem ceeb uas ua rau warping thiab deformation, thiab muaj kev cuam tshuam ntau dua rau qhov zoo ntawm cov khoom txhaj tshuaj molded. Txij li thaum qhov cuam tshuam ntawm qhov seem thermal stress ntawm cov khoom warpage yog qhov nyuaj heev, cov tsim pwm tuaj yeem txheeb xyuas thiab kwv yees nws nrog kev pab los ntawm kev txhaj tshuaj molding CAE software.
Thaum lub sij hawm molding txheej txheem ntawm cov yas yaj, vim yog qhov tsis sib xws ntawm kev taw qhia thiab shrinkage, qhov kev ntxhov siab sab hauv tsis sib xws, yog li tom qab cov khoom raug tso tawm los ntawm pwm, nws yuav warp thiab deform nyob rau hauv qhov kev txiav txim ntawm qhov tsis sib xws ntawm kev ntxhov siab. Yog li ntawd, ntau tus kws tshawb fawb soj ntsuam thiab xam cov kev ntxhov siab sab hauv thiab kev sib ntaus sib tua ntawm cov khoom los ntawm kev xav ntawm mechanics. Hauv qee cov ntaub ntawv txawv teb chaws, kev sib ntaus sib tua yog suav tias yog tshwm sim los ntawm cov kev ntxhov siab uas tshwm sim los ntawm qhov tsis sib xws.
Nyob rau hauv lub caij txias ntawm kev txhaj tshuaj molding, thaum qhov kub siab tshaj qhov kub hloov pauv iav, cov yas yog cov kua viscoelastic, nrog rau kev ntxhov siab: thaum qhov kub thiab txias qis dua qhov kub hloov pauv iav, cov yas yuav ua tau zoo. Qhov kev hloov pauv ntawm cov kua-khoom no thiab kev ntxhov siab so ntawm cov yas thaum lub caij txias muaj qhov cuam tshuam zoo rau kev kwv yees qhov tseeb ntawm cov kev ntxhov siab seem thiab cov khoom seem deformation.
Cov theem hloov thiab kev ntxhov siab so tus cwj pwm ntawm cov yas los ntawm cov kua rau cov khoom thaum lub sij hawm txias. Rau thaj chaw uas tsis muaj kev kho mob, cov yas nthuav tawm cov cwj pwm viscous, uas tau piav qhia los ntawm cov qauv ua kua dej khov; rau thaj chaw kho mob, cov yas nthuav tawm tus cwj pwm viscoelastic, uas tau piav qhia los ntawm tus qauv linear khoom qauv, siv cov qauv hloov pauv visco-elastic theem thiab ob-dimensional finite element txoj kev los kwv yees thermal residual stresses thiab sib xws warpage deformations.
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Kev cuam tshuam ntawm plasticizing theem ntawm cov khoom warping deformation
Nyob rau hauv lub plasticizing theem, cov iav hais yog hloov mus rau hauv ib tug viscous kua xeev los muab cov yaj xav tau rau sau pwm. Hauv cov txheej txheem no, qhov kub ntawm qhov sib txawv ntawm cov polymer nyob rau hauv axial kev taw qhia thiab radial kev taw qhia (kwv yees rau cov ntsia hlau) yuav ua rau muaj kev ntxhov siab hauv cov yas; Tsis tas li ntawd, kev txhaj tshuaj siab, ceev thiab lwm yam tsis zoo ntawm lub tshuab txhaj tshuaj yuav cuam tshuam rau qib ntawm molecular orientation thaum sau. , ua rau warping deformation.
Siv ceev ceev thaum pib ntawm kev txhaj tshuaj, kev kub ceev thaum sau cov pwm kab noj hniav, thiab tsis tshua muaj kev txhaj tshuaj thaum filling yog ze rau qhov kawg. Los ntawm kev tswj thiab kev hloov kho ntawm kev txhaj tshuaj nrawm, ntau yam tsis zoo tshwm sim xws li burrs, tshuaj tsuag cov cim, nyiaj tuav lossis cov cim hlawv tuaj yeem tiv thaiv thiab txhim kho.
Cov txheej txheem kev txhaj tshuaj ntau theem tuaj yeem tsim teeb tsa ntau theem kev txhaj tshuaj siab, txhaj tshuaj ceev, tuav lub siab thiab yaj txoj kev raws li tus qauv ntawm tus khiav, daim ntawv ntawm lub rooj vag thiab cov qauv ntawm kev txhaj tshuaj molded ib feem, uas yog qhov tsim nyog. los txhim kho cov nyhuv plasticizing thiab txhim kho cov khoom zoo, txo qis tus nqi thiab ncua pwm / tshuab lub neej.
Los ntawm kev tswj cov roj siab, ntsia hlau txoj hauj lwm, thiab ntsia hlau ceev ntawm lub tshuab txhaj tshuaj molding los ntawm ntau theem kev pab cuam, nws tuaj yeem nrhiav kev txhim kho qhov zoo li ntawm cov pwm pwm, txhim kho cov kev ntsuas sib xws rau shrinkage, warping thiab burr, thiab txo qhov qhov loj unevenness ntawm txhua txhaj molded ib feem ntawm txhua pwm. .
Los ntawm kev tswj cov roj siab, txoj haujlwm ntsia hlau thiab ntsia hlau ceev ntawm lub tshuab txhaj tshuaj molding los ntawm ntau theem kev pab cuam, nws tuaj yeem nrhiav kev txhim kho qhov zoo li ntawm cov pwm pwm, txhim kho cov kev ntsuas sib xws rau shrinkage, warping thiab burr, thiab txo qhov tsis sib xws. ntawm qhov loj ntawm txhua qhov txhaj tshuaj molded ib feem ntawm txhua pwm. .
Kev cuam tshuam ntawm pwm filling thiab txias theem ntawm cov khoom warpage
Nyob rau hauv qhov kev txiav txim ntawm kev txhaj tshuaj, cov yas molten yog ntim rau hauv pwm kab noj hniav, txias thiab solidified nyob rau hauv cov kab noj hniav, uas yog qhov tseem ceeb ntawm kev txhaj tshuaj molding. Nyob rau hauv cov txheej txheem no, qhov kub thiab txias, siab, thiab ceev yog ua ke nrog ib leeg, uas muaj kev cuam tshuam zoo rau cov khoom zoo thiab kev ua haujlwm ntawm cov khoom yas.
Kev kub siab ntau dua thiab cov dej ntws tawm ua rau muaj kev sib tw siab, uas ua rau muaj qhov sib txawv ntawm qhov kev taw qhia ntawm cov molecules thaum uas tig mus thiab perpendicular mus rau cov kev taw qhia ntawm ntws, tsim kom muaj "cov nyhuv khov". Qhov "freezing effect" yuav tsim kom muaj kev ntxhov siab khov thiab tsim cov kev ntxhov siab sab hauv ntawm cov yas. Qhov cuam tshuam ntawm qhov kub thiab txias ntawm warping deformation yog tshwm sim hauv cov hauv qab no.
A. Qhov sib txawv ntawm qhov kub thiab txias ntawm qhov chaw ntawm cov khoom yas yuav ua rau thermal stress thiab thermal deformation;
B. Qhov kub ntawm qhov sib txawv ntawm qhov sib txawv ntawm cov yas yuav ua rau qhov sib txawv ntawm qhov sib txawv;
C. Cov xeev kub sib txawv yuav cuam tshuam rau qhov shrinkage ntawm cov khoom yas.
Kev cuam tshuam ntawm theem demoulding ntawm warping deformation ntawm cov khoom
Cov khoom yas feem ntau yog cov iav polymers thaum lub sijhawm tawm hauv cov kab noj hniav thiab ua kom txias rau chav sov. Unbalanced demoulding quab yuam, tsis ruaj khov txav ntawm lub ejection mechanism los yog tsis tsim nyog ejection cheeb tsam ntawm lub demoulding tau yooj yim deform cov khoom. Nyob rau tib lub sijhawm, qhov kev ntxhov siab khov rau hauv cov yas yas thaum lub sij hawm txhaws thiab txias yuav raug tso tawm rau hauv daim ntawv ntawm deformation vim qhov poob ntawm cov kev txwv sab nraud, uas ua rau warping deformation.
Muaj tseeb 3D txoj hauv kev los xam cov kev ntxhov siab thiab qhov kawg (shrinkage thiab warpage). Lawv tau txiav txim siab qhov cuam tshuam ntawm cov txheej txheem ntim khoom, muab cov khoom faib ua peb txheej, thiab txheeb xyuas qhov seem ntawm kev ntxhov siab thiab deformation los ntawm peb-seem mesh. , ib tug lej simulation qauv rau induced residual kev nyuaj siab thiab deformation tom qab lub packing theem yog npaj.
Thaum xam cov kev ntxhov siab seem, siv cov qauv thermoviscoelastic (nrog rau lub ntim so) yog siv. Cov txheej txheem finite nws txais yuav yog raws li lub plhaub txoj kev xav uas tsim los ntawm cov ntsiab lus, uas yog tsim rau nyias-walled txhaj molded cov khoom nrog cov duab complex.
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Kev daws rau cov nyhuv ntawm shrinkage ntawm txhaj tshuaj molded khoom ntawm warping deformation
Qhov ncaj qha ua rau warpage ntawm kev txhaj tshuaj molded cov khoom yog qhov tsis sib xws ntawm cov khoom yas. Yog hais tias qhov cuam tshuam ntawm shrinkage thaum lub sij hawm ntim cov txheej txheem tsis tau txiav txim siab nyob rau hauv lub pwm tsim theem, cov duab geometric ntawm cov khoom yuav txawv heev los ntawm cov qauv tsim, thiab deformation hnyav yuav ua rau cov khoom tawg. Ntxiv nrog rau qhov deformation tshwm sim los ntawm lub sijhawm txhaws, qhov kub sib txawv ntawm cov phab ntsa sab saud thiab sab qis ntawm cov pwm kuj yuav ua rau qhov sib txawv ntawm qhov shrinkage ntawm sab sauv thiab qis ntawm cov yas, uas ua rau warping deformation.
Rau kev tsom xam warpage, shrinkage nws tus kheej tsis yog qhov tseem ceeb, tab sis qhov sib txawv ntawm shrinkage yog qhov tseem ceeb. Nyob rau hauv cov txheej txheem txhaj tshuaj molding, qhov shrinkage tus nqi ntawm cov yas nyob rau hauv cov kev taw qhia ntws yog ntau dua li nyob rau hauv ntsug kev taw qhia vim hais tias ntawm cov txheej txheem ntawm cov polymer molecules nyob rau hauv lub khiav kev taw qhia thaum lub sij hawm txhaj molding theem ntawm cov yas molten, uas ua rau warping deformation. ntawm qhov txhaj tshuaj molded ib feem. Feem ntau, cov shrinkage tsis sib xws tsuas yog ua rau muaj kev hloov pauv ntawm qhov ntim ntawm cov khoom yas, thiab tsuas yog cov shrinkage tsis sib xws tuaj yeem ua rau warping deformation.
Qhov sib txawv ntawm qhov shrinkage tus nqi ntawm crystalline plastics nyob rau hauv cov kev taw qhia ntws thiab ntsug ntsug yog loj dua li ntawm amorphous plastics, thiab nws cov shrinkage tus nqi kuj loj dua li ntawm amorphous plastics. Lub superposition ntawm qhov loj shrinkage tus nqi ntawm crystalline plastics thiab lub anisotropy ntawm shrinkage ua rau Crystalline plastics muaj ntau yam zoo li warp tshaj amorphous plastics.
Cov txheej txheem txhaj tshuaj molding ntau theem tau xaiv raws li kev txheeb xyuas ntawm cov duab geometric ntawm cov khoom: vim tias cov kab noj hniav ntawm cov khoom sib sib zog nqus thiab cov phab ntsa yog nyias, cov pwm kab noj hniav ua rau ntev thiab nqaim ntws channel, thiab cov yaj yuav tsum ntws. los ntawm qhov no sai heev Txwv tsis pub, nws yog ib qho yooj yim kom txias thiab solidify, uas yuav ua rau muaj kev txaus ntshai ntawm kev sau cov pwm kab noj hniav, yog li high-speed txhaj tshuaj yuav tsum tau teem rau ntawm no.
Txawm li cas los xij, kev txhaj tshuaj ceev ceev yuav coj ntau lub zog kinetic rau yaj. Thaum cov yaj ntws mus rau hauv qab, nws yuav ua rau muaj kev cuam tshuam loj inertial, ua rau lub zog poob thiab dhau mus. Thaum lub sij hawm no, lub yaj yuav tsum tau qeeb thiab lub filling siab yuav tsum tau txo. Tuav qhov hu ua tuav siab (siab siab, kev ua raws li kev siab) ua kom cov yaj ntxiv cov shrinkage ntawm cov yaj mus rau hauv pwm kab noj hniav ua ntej lub rooj vag solidifies, uas tso rau pem hauv ntej yuav tsum tau rau ntau theem txhaj tshuaj ceev thiab siab ntawm txhaj tshuaj. txheej txheem molding.
Kev daws rau cov khoom warping thiab deformation vim residual thermal stress
Qhov nrawm ntawm cov dej saum npoo yuav tsum tsis tu ncua. Kev txhaj tshuaj sai yuav tsum tau siv los tiv thaiv cov yaj los ntawm khov thaum lub sijhawm txhaj tshuaj. Qhov chaw txhaj tshuaj nrawm yuav tsum tso cai kom nrawm nrawm rau hauv qhov chaw tseem ceeb (xws li cov neeg khiav dej num) thaum qeeb ntawm cov dej nkag. Kev txhaj tshuaj nrawm yuav tsum xyuas kom meej tias cov pwm kab noj hniav tau ntim thiab nres tam sim ntawd txhawm rau tiv thaiv overfilling, flash thiab residual stress.
