Vim li cas pob tshab txhaj tshuaj pwm zoo li PC thiab PMMA thiaj li muaj teeb meem? Dab tsi yog qhov tseem ceeb ntawm kev tsim qauv kev txiav txim siab rau cov pob tshab? Vim li cas, txawm tias ob qho tib si yog cov ntaub ntawv pob tshab, PC puas cuam tshuam ntau dua - tiv taus PMMA?
- Dab tsi yog qhov tseem ceeb ntawm cov qauv tsim kev txiav txim siab rau pob tshab txhaj tshuaj pwm zoo li PC thiab PMMA?
- Vim li cas, txawm tias ob qho tib si pob tshab, yog cov khoom tsim los ntawm PC muaj kev cuam tshuam ntau dua - tiv taus ntau dua li cov khoom tsim los ntawm PMMA?
Muaj ob peb hom yas siv rau cov khoom yas pob tshab, tab sis acrylic (PMMA) thiab polycarbonate (PC) yog cov khoom siv pob tshab uas feem ntau xaiv thiab siv dav. Cov qauv tsim ntawm pob tshab txhaj tshuaj molded qhov chaw yuav tsum tau saib xyuas zoo, raws li kev saib xyuas me ntsis tuaj yeem tig ib qho khoom los ntawm crystal ntshiab mus rau qhov tsis zoo-ridden, nthuav tawm ntau qhov "muaj peev xwm pitfalls" uas yuav tsum tau zam hauv kev tsim. Yog tias koj tau rov kho cov txheej txheem txhaj tshuaj molding rau koj qhov pob tshab thiab tseem tsis txaus siab rau cov txiaj ntsig, nws muaj feem ntau qhov teeb meem nyob rau hauv cov qauv tsim ntawm nws tus kheej.
Phab ntsa thickness tsim yog thawj qhov kev txiav txim siab rau pob tshab txhaj tshuaj molded qhov chaw, raws li qhov teeb meem tseem ceeb tshaj plaws rau cov pob tshab yog qhov hloov pauv sai ntawm phab ntsa thickness. Qhov no tuaj yeem ua rau lub teeb tsis sib xws, ua rau pom tseeb streaks ntawm lub teeb thiab duab ntxoov ntxoo. Cov qauv tsim zoo tshaj plaws yuav tsum tswj cov phab ntsa tuab, nrog rau kev hloov pauv hloov tsis pub ntau tshaj 0.5mm ib 10mm. Rau cov khoom siv acrylic (PMMA), qhov pom zoo ntawm phab ntsa thickness yog 3-8 hli; rau PC qhov chaw, nws tuaj yeem ua rau nyias nyias, feem ntau 2-6 hli. Nws yog ib qho tseem ceeb tshwj xeeb tshaj yog tsim kom txaus fillet radii ntawm cov ces kaum, nrog rau qhov tsawg kawg nkaus ntawm qhov tsawg kawg nkaus ntawm 0.5 npaug ntawm phab ntsa thickness. Txwv tsis pub, kev ntxhov siab tuaj yeem tshwm sim thaum txhaj tshuaj molding.
Tom ntej no yog lub kaum sab xis.Kev tswj ntawm lub kaum sab xis rau pob tshab yog qhov tseem ceeb tshwj xeeb. Cov pob tshab muaj qhov yuav tsum tau nruj dua rau cov kaum sab xis dua li cov khoom yas zoo tib yam, feem ntau xav tau 1.5-3℃. Lub kaum sab xis ntawm qhov tsau (kab noj hniav) sab yuav tsum yog 0.5℃loj dua ntawm qhov txav (core) sab. Qhov kev nthuav dav no zoo pab tiv thaiv khawb thaum ejection. Rau qhov sib sib zog nqus-cav pob tshab, lub kaum sab xis yuav tsum tau nce mus rau 5℃lossis ntau dua. Nws yog ib qho tseem ceeb tshwj xeeb uas yuav tsum nco ntsoov tias txhua tus qauv tsim muaj qhov tsis zoo ntawm lub kaum sab xis yog txwv tsis pub, vim tias nws yuav ua rau muaj kev puas tsuaj rau qhov chaw thaum lub sij hawm ejection.
Tom qab ntawd muaj lub rooj vag thiab khiav.Lub rooj vag tsim rau pob tshab qhov chaw ncaj qha cuam tshuam rau qhov tshwm sim ntawm qhov muag. Cov rooj vag ncaj yuav tsum raug zam rau cov pob tshab, vim tias lawv tawm cov kab uas pom tseeb ntawm qhov chaw. Submarine (tunnel) cov rooj vag lossis cov rooj vag kiv cua yog qhov kev xaiv zoo dua, tab sis qhov ntev ntawm lub rooj vag yuav tsum tau muab xam kom meej- me me dhau ua rau kev txhaj tshuaj luv luv, loj dhau ua rau cov cim ntws. Kev paub qhia tau hais tias lub rooj vag thickness yuav tsum tau tswj ntawm 50-70% ntawm ib feem ntawm phab ntsa thickness, thiab qhov dav yog pom zoo kom 2-3 npaug ntawm phab ntsa thickness. Rau qhov loj pob tshab uas siv ntau lub rooj vag, ib qho kev sib tw khiav yog qhov tseem ceeb los xyuas kom meej tias cov dej ntws mus rau pem hauv ntej zoo ib yam.
Tsis tas li ntawd, kev tuav cov qauv kev sib txuas hauv cov pob tshab yuav tsum tau ceev faj ntxiv.Direct ntsia hlau fastening yuav tsum tau zam rau pob tshab qhov chaw thaum twg los tau, vim nws tsim kom muaj kev nyuaj siab concentration. Chemical bonding los yog mechanical snap- haum txoj kev raug pom zoo. Yog tias yuav tsum tau siv cov ntsia hlau, kev ntxhov siab txaus- cov grooves yuav tsum tau tsim nyob ib ncig ntawm lub taub hau ntsia hlau. Kev xaiv ntawm cov nplaum kuj tseem ceeb. Thaum UV- kho cov nplaum nplaum yooj yim, lawv yooj yim rau yellowing lub sijhawm. Optically ntshiab epoxy resins raug pom zoo; Txawm hais tias lawv muaj lub sijhawm kho ntev dua, lawv ua kom pom tseeb thiab ruaj khov.
Yog tias koj qhov pob tshab yuav tsum tau kho saum npoo, Ntau tus neeg ntseeg tias cov khoom pob tshab yuav tsum tau siab - qib polishing, tab sis qhov tseeb, polishing ntau dhau tuaj yeem ua rau pom qhov khawb ntau dua. Txoj kev tshaj lij yog siv cov txheej txheem pob zeb diamond polishing, ua tiav SPI A2 qib tiav. Lwm qhov kev xav tsis zoo yog siv cov tshuaj tiv thaiv zoo tib yam - khawb, uas tuaj yeem ua rau lub teeb tawg. Txoj kev raug yog xaiv nano- txheej txheej uas phim lub refractive index, uas tiv thaiv saum npoo yam tsis muaj kev cuam tshuam lub teeb transmittance.
Tsis tas li ntawd, qhov yuav tsum tau ua rau pwm tsim rau pob tshab qhov chaw yog ze li ntawm stringent. Pwm core thiab kab noj hniav rau pob tshab qhov chaw yuav tsum yog ua los ntawm daim iav - polished steel (xws li S136H), nrog ib tug hardness ntawm HRC 52 los yog siab dua. Lub tshuab cua txias tsim yuav tsum tau ceev faj ntau dua; Conformal cua txias raws tau pom zoo kom ntseeg tau tias pwm kub hloov pauv tau tswj tsis pub dhau ± 1 degree. Lub venting system kuj tsis tuaj yeem tsis quav ntsej; venting grooves ntawm 0.02-0.03mm yuav tsum tau teem rau ntawm qhov kawg qhov chaw kom sau, uas yog ib qho tseem ceeb heev kom tsis txhob muaj nyiaj streaks. Nws yog tsim nyog hais tias kev txiav txim siab rau covsiv ib puag ncig ntawm pob tshab qhov feem ntau tsis saib xyuas.Acrylic (PMMA) yellows nyob rau hauv lub sij hawm ntev UV raug. PC muaj kev tiv thaiv UV zoo dua, tab sis nws yooj yim rau kev ntxhov siab tawg nyob rau hauv siab - qhov kub thiab txias. Kev tsim qauv yuav tsum zam kom tsis txhob cuam tshuam ncaj qha rau cov pob tshab rau qhov chaw hnyav; UV stabilizers yuav tsum tau ntxiv thaum tsim nyog. Thermal expansion vim qhov kub hloov pauv kuj tsis tuaj yeem tsis quav ntsej. Kev nthuav dav txaus yuav tsum tau muab rau kev teeb tsa ntawm pob tshab, feem ntau 0.5mm rau 100mm ntawm qhov ntev.
Thaum kawg, hais txog qhov kev kuaj xyuas ua ntej ua ntej kev tsim cov pob tshab yog qhov tseem ceeb.Ntxiv rau qhov kev tshuaj xyuas qhov ntev niaj hnub, cov khoom pob tshab tshwj xeeb yuav tsum tau kuaj qhov muag tsis pom kev, ntsuas kev ntxhov siab birefringence, thiab kuaj huab cua. Nws raug nquahu kom siv lub polariscope los tshuaj xyuas cov kev ntxhov siab sab hauv; thaj chaw ntawm kev ntxhov siab concentration yuav pom cov xim fringes. Kev ntsuas kev laus nrawm yuav tsum simulate tsawg kawg 3 xyoos ntawm kev siv, uas yog ib txoj hauv kev zoo rau kev nthuav tawm cov teeb meem uas yuav tshwm sim.
Tau npog ntau, cia peb sau tseg: Cov qauv tsim ntawm pob tshab txhaj tshuaj molded qhov chaw yuav tsum tsis txhob hloov pauv ntawm phab ntsa tuab, nruj me ntsis txwv tsis pub cov kaum sab xis tsis zoo, siv cov hlau ntxig kom ceev faj, nyob deb ntawm cov ces kaum ntse, thiab tswj qhov chaw ntawm cov kab txuas. Muab cov ntsiab lus tseem ceeb no rau hauv cov qauv tsim tshwj xeeb yog txoj hauv kev los tsim cov khoom zoo nkauj thiab txhim khu kev qha pob tshab. Cov pob tshab zoo tsim yuav tsum ua kom tiav cov qauv xws li: lub teeb xa hluav taws xob poob qis dua 5%, nplaim taws poob qis dua 1%, thiab tiv thaiv yellowing rau 5 xyoo raws li kev siv ib txwm muaj.
Tom ntej no, cia peb tham txog vim li cas, txawm tias ob qho tib si yog cov ntaub ntawv pob tshab, PC muaj kev cuam tshuam ntau dua - tiv taus PMMA?
Tseeb, ntawm cov yas pob tshab, PMMA (acrylic) thiab PC (polycarbonate) feem ntau yog muab piv: ob qho tib si pob tshab, ob qho tib si tuaj yeem txhaj tshuaj molded, thiab ob qho tib si tuaj yeem siv rau qhov chaw kho qhov muag. Tab sis thaum nws los txog rau "kev cuam tshuam tsis zoo," qhov sib txawv yuav luag dhau. Cia peb xub saib ib pawg ntawm cov ntaub ntawv:
PMMA cuam tshuam lub zog: kwv yees li 2-10 kJ / m²
- PC Impact Strength: tuaj yeem siab li 60-80 kJ / m² (los yog siab dua)
Qhov no txhais li cas?
Nyob rau hauv tib qho kev cuam tshuam hnyav, PMMA yuav cuam tshuam rau qhov cuam tshuam, thaum PC tuaj yeem sib tw, deform, thiab "sab" qhov cuam tshuam lub zog, tseem tsis tau tawg nws tus kheej.
Vim li cas, txawm tias ob qho tib si yog pob tshab yas, puas muaj qhov sib txawv ntawm qhov sib txawv?
Niaj hnub no, peb yuav rhuav tshem cov lus nug no zoo li yooj yim tab sis tseem ceeb, los ntawm cov ntsiab lus ntawm kev cuam tshuam → molecular qauv → saw ntu txav → lub cev lub cev.
Ntau tus neeg xav tias qhov cuam tshuam tsis zoo yog hais txog "hardness." Nws yeej tsis yog li ntawd kiag li.
Qhov cuam tshuam kev ua tau zoo ntawm cov ntaub ntawv pob tshab yog los ntawm peb lub peev xwm:
- Muaj peev xwm ua kom raug mob (yas deformation):Cov khoom puas tuaj yeem cuam tshuam cov yas deformation (xws li ncab, khoov) thaum muaj kev cuam tshuam, cuam tshuam lub zog ntawm ib cheeb tsam es tsis yog tsom rau ntawm qhov taw tes?
- Muaj peev xwm nqus tau lub zog (zog dissipation):Cov khoom siv microstructure puas tuaj yeem ua rau cov khoom siv hluav taws xob (molecular chains, chains) dissipate lub kinetic impact zog los ntawm kev hloov mus rau lwm hom zog (xws li cua sov) los ntawm cov txheej txheem xws li slippage, shear, thiab orientation thaum raug quab yuam?
- Muaj peev xwm tso cai rau cov yas deformation ntau yam tsis tau poob pob tshab:Qhov no yog qhov kev sib tw kawg rau pob tshab engineering plastics. Ntau cov ntaub ntawv tuaj yeem nqus tau lub zog, tab sis ib zaug ncab, lawv tsim crazing (kev nyuaj siab whitening), ua rau lub teeb tawg thiab tsis pom tseeb. Sab saum toj -tier pob tshab, cuam tshuam- cov ntaub ntawv tiv taus yuav tsum ua tiav "pob tshab yielding."
PC ua tau zoo hauv tag nrho peb yam, thaum PMMA muaj qhov tsis txaus ntseeg hauv thawj ob.
Cia peb pib los ntawm saib PMMA.
PMMA's "siab rigidity" ntawm cov ntaub ntawv pob tshab yog ib qho zoo dua: haum rau optics, haum rau kev txhawb nqa, tsis muaj qhov deformation. Tab sis qhov no kuj tau tso lub hauv paus rau nws "kev cuam tshuam tsis zoo."
- PMMA cov chains yog nruj heev, thiab nws cov pab pawg sab nrauv loj dhau:
PMMA cov qauv muaj ib pab pawg "loj heev": -COO–CH₃ (methyl ester pawg)
Cov pab pawg loj no muaj qhov cuam tshuam loj heev, ua rau:
- Nyuaj rau cov ntu ntu kom twist
- Nyuaj rau cov molecules kom plam
- Kev txwv nruj heev hauv zos
- Nws zoo li kev tsav cov kab nrib pleb ntawm cov ntu ntu, cuam tshuam kev sib hloov thiab kev poob ntawm cov saw hlau molecular.
- PMMA muaj qhov hloov pauv iav siab heev (Tg):
PMMA's Tg ≈ 105℃.
Nyob rau hauv chav tsev kub, uas nyob deb ntawm qhov ntsuas kub no, nws cov saw hlau molecular yog nyob rau hauv lub "khov" glassy lub xeev nrog tsis tshua muaj kev txav mus los.
- PMMA tsis muaj cov qauv uas "tiv thaiv kev tawg tawm":
PMMA molecular chains tsis tu ncua. Thaum microcracks tsim nyob rau hauv kev ntxhov siab, lub qhov tawg nrawm nrawm nrawm zog thiab nthuav tawm zoo li xob laim raws cov saw hlau molecular yuav luag tsis muaj kev cuam tshuam. Nws qhov tawg yog qhov raugbrittle puas-Sim me me, tawg sai sai, thiab rhiab heev rau qhov chaw.
PMMA zoo li ib daim iav me me, tawv tawv, nrog kev nruj nruj, tab sis raws li qhov cuam tshuam, nws cov "xauv" cov ntu tsis tuaj yeem cuam tshuam lub zog los ntawm kev txav mus los. Nws tsuas tuaj yeem "tiv taus" kom txog thaum nws tawg.
Tam sim no, cia peb saib PC. PC cov qauv molecular zoo kawg nkaus qhia qhov nws txhais tau tias "ob leeg nruj thiab yoog raws."
Nws cov qauv yog tsim los ntawmBisphenol A + carbonate pawg, thiab cov qauv no muaj ob yam tseem ceeb:
- Benzene nplhaib + carbonate → siab saw rigidity, tab sis tsis xauv:
PC's chains muaj ntau lub nplhaib benzene, tab sis cov rings no tsis yog "nkig nruj." Hloov chaw:
Cov benzene rings muab lub zog thiab nruj, thaum cov carbonate pawg ua raws li "cov pob qij txha", uas tso cai rau cov saw hlau molecular kom muaj kev sib hloov loj thiab khoov thaum muaj kev ntxhov siab. Qhov no muab siab rigidity (tsim pob tshab / lub zog) thaum tseem muaj cov saw hloov tau yooj yim (muab kev toughness).
- PC lub peev xwm tseem ceeb: Yielding deformation rau lub zog nqus:
Qhov no yog lub hauv paus mechanism ntawm PC lub siab toughness. Raws li kev quab yuam, PC tsis tawg ncaj qha zoo li PMMA. Xwb, nws thawj zaug undergoeskev tawm los.
Molecular chains plam thiab orient, tsim ntau heevshear bands. Kev tsim ntawm txhua qhov shear band siv lub zog loj, ua haujlwm zoo li lub zog sab hauv absorber.
PMMA yog ib daim iav tawv; PC yog ib daim hlau phaj uas tuaj yeem ncab pob tshab.
- Crack propagation hauv PC yog "intercepted" los ntawm shear bands:
Qhov no yog qhov kev txiav txim siab sib txawv. Lub manifestation yog raws li nram no:
- PMMA: Thaum cov ntaub ntawv tawg, nws nthuav tawm hauv txoj kab ncaj nraim, nkag mus rau cov ntaub ntawv sai.
- PC: Thaum cov kab nrib pleb sim nthuav tawm hauv PC, nws ntsib tsis yog txoj hauv kev ua ntej, tab sis lub network ntawm crisscrossing shear bands thiab yas deformation zones. Cov cheeb tsam no ua rau lub ntsej muag tawg, cuam tshuam nws txoj kev nthuav dav, thiab nqus nws lub zog, thaum kawg ua rau qhov tawg rau "shaus nws tus kheej" thiab nres.
Thaum kawg, cia peb xaus qhov sib txawv ntawm qhov toughness ntawm ob cov ntaub ntawv pob tshab, PC thiab PMMA:
- PMMA muaj qhov siab -rigidity chains "locked" los ntawm cov pab pawg sab nraud, ua rau cov pob txha tawg.
- PC muaj qhov nruj- cov pob txha pob txha nrog "cov pob qij txha hloov tau," muaj peev xwm nqus tau lub zog los ntawm cov khoom yas deformation.
Qhov kev sib txawv ntawm cov qauv no ua rau ib qhonruab nrab 8-10 zaug lossis ntau dua qhov sib txawv ntawm qhov cuam tshuam lub zognyob rau hauv lawv cov macroscopic zog. Yog li ntawd, lawv cov kev xaiv ntawm daim ntawv thov kuj txawv heev:
- PC dominates nyob rau hauv cov cheeb tsam uas yuav tsum tau muaj zog toughness, tej yam kuj, thiab durability: piv txwv li, riot shields, tsom iav kev nyab xeeb, tsheb headlamp lo ntsiab muag, drone gimbal npog, thiab poob -cov casings resistant rau hluav taws xob.
- PMMA ua tau zooNyob rau hauv cov cheeb tsam uas siab deg hardness, khawb kuj, zoo weatherability, thiab zoo heev optical zog yog qhov tseem ceeb: piv txwv li, automotive taillight lo ntsiab muag, optical lo ntsiab muag, lub teeb qhia daim hlau, advertising lub thawv, thiab thoob dej yug ntses.
