Nyob rau hauv tag nrho cov txheej txheem ntau lawm ntawm niaj hnub PCB, tus cwj mem tau dhau los ua ib qho ntawm cov khoom siv tseem ceeb hauv kev tsim cov txheej txheem PCB ntawm PCB factories. Nws tuav txoj haujlwm tseem ceeb heev hauv cov ntaub ntawv txheej txheem PCB. Kev ua tiav lossis tsis ua tiav ntawm kev siv tus cwj mem ncaj qha cuam tshuam rau tag nrho cov kev xav tau thiab cov cim qhia zoo ntawm PCB xa khoom. Vim li no, PCB manufacturers muab qhov tseem ceeb rau kev ua tau zoo ntawm inks. Ntxiv rau qhov paub zoo tus cwj mem viscosity, thixotropy raws li tus cwj mem feem ntau pom los ntawm tib neeg. Tab sis nws plays lub luag haujlwm tseem ceeb hauv cov nyhuv ntawm kev tshuaj ntsuam luam ntawv.

Hauv qab no peb txheeb xyuas thiab tshawb xyuas qhov cuam tshuam ntawm thixotropy hauv PCB system ntawm tus cwj mem ua haujlwm:

1. Vijtsam

Silk screen yog ib qho ntawm cov khoom siv tseem ceeb hauv cov txheej txheem luam ntawv. Yog tsis muaj tshuaj ntsuam, nws tsis tuaj yeem hu ua kev tshuaj ntsuam luam ntawv. Screen printing yog tus ntsuj plig ntawm kev tshuaj ntsuam luam ntawv thev naus laus zis. Cov ntxaij vab tshaus yog yuav luag tag nrho cov ntaub lo lo ntxhuav (tawm kuj tseem muaj cov ntaub tsis txhob lo lo ntxhuav).

Hauv kev lag luam PCB, feem ntau siv yog t-hom net. s thiab hd hom tes hauj lwm feem ntau tsis siv tshwj tsis yog rau cov kev xav tau tshwj xeeb.

2. Ink

Hais txog cov xim gelatinous siv rau cov ntawv luam tawm. Nws feem ntau yog tsim los ntawm cov khoom siv hluavtaws, cov kuab tshuaj tsis muaj zog, cov roj thiab cov muab tub lim, desiccants, pigments thiab diluents. Feem ntau hu ua number case.

Peb. Ntau yam tseem ceeb ntawm cov khoom ntawm PCB number case

Txawm hais tias qhov zoo ntawm PCB number case yog qhov zoo heev, hauv txoj cai, nws tsis tuaj yeem tawg tawm ntawm kev sib xyaw ntawm cov khoom tseem ceeb saum toj no. Qhov zoo heev ntawm tus number case yog ib qho kev qhia dav dav ntawm kev tshawb fawb, kev nce qib thiab kev tiv thaiv ib puag ncig ntawm cov qauv. Nws yog reflected nyob rau hauv:

(1) Viscosity: luv rau dynamic viscosity. Feem ntau qhia los ntawm viscosity, uas yog, shear stress of fluid flow faib los ntawm kev tshaj tawm gradient nyob rau hauv cov kev taw qhia ntawm lub ntws txheej, lub thoob ntiaj teb chav tsev yog Pa/sec (pa.s) los yog milliPascal/sec (mpa.s). Hauv PCB ntau lawm, nws hais txog fluidity ntawm tus number case uas tsim los ntawm sab nraud rog.

(2) Plasticity: Tom qab tus number case deformed los ntawm sab nraud quab yuam, nws tseem khaws nws cov khoom ua ntej deformation. Lub plasticity ntawm tus number case yog qhov zoo rau kev txhim kho kev luam ntawv raug;

(3) Thixotropic: (thixotropic) Tus number case yog gelatinous thaum nws sawv ntsug, thiab cov viscosity hloov thaum kov. Nws tseem hu ua thixotropic thiab sag kuj;

(4) Fluidity: (leveling) qhov twg tus number case kis tau nyob ib ncig ntawm qhov kev txiav txim ntawm sab nraud quab yuam. Fluidity yog reciprocal ntawm viscosity, thiab fluidity yog txuam nrog plasticity thiab thixotropy ntawm tus number case. Lub plasticity thiab thixotropy yog loj, fluidity yog loj; lub fluidity yog loj, lub imprint yog ib qho yooj yim mus nthuav. Nrog tsis tshua muaj fluidity, nws yog nquag mus rau network tsim, ua rau ink tsim, uas tseem hu ua reticulation;

(5) Viscoelasticity: yog hais txog lub peev xwm ntawm tus number case uas sheared thiab tawg tom qab tus number case yog scraped los ntawm tus squeegee kom rebound sai. Nws yuav tsum tau hais tias tus number case deformation ceev ceev thiab tus number case rebounds sai sai yuav zoo rau luam ntawv;

(6) Dryness: qhov qeeb qeeb ntawm qhov ziab ntawm tus number case ntawm lub vijtsam, qhov zoo dua, thiab qhov nrawm dua qhov zoo dua tom qab tus number case raug xa mus rau substrate;

(7) Fineness: qhov loj ntawm cov xim thiab cov khoom siv cov khoom, PCB number case feem ntau tsawg dua 10μm, thiab qhov loj ntawm qhov zoo yuav tsum tsawg dua li ib feem peb ntawm qhov qhib mesh;

(8) Stringiness: Thaum tus number case tau khaws nrog tus cwj mem, qhov degree uas tus number case zoo li tsis tawg thaum ncab yog hu ua stringiness. Tus number case filament yog ntev, thiab muaj ntau cov filaments ntawm tus number case nto thiab luam ntawv nto, ua rau cov substrate thiab cov ntawv luam ntawv qias neeg, los yog txawm tsis tuaj yeem luam tawm;

(9) Transparency thiab zais lub hwj chim ntawm tus number case: Rau PCB inks, ntau yam yuav tsum tau muab tso rau pem hauv ntej rau lub pob tshab thiab zais lub zog ntawm tus number case raws li kev siv thiab kev xav tau sib txawv. Feem ntau hais lus, circuit inks, conductive inks thiab cim inks txhua tus yuav tsum muaj lub zog zais siab. Lub solder resist yog yooj yim dua.

(10) Tshuaj tiv thaiv ntawm tus number case: PCB number case muaj cov qauv nruj rau cov kua qaub, alkali, ntsev thiab hnyav raws li cov hom phiaj sib txawv;

(11) Lub cev tsis kam ntawm tus number case: PCB number case yuav tsum ua tau raws li cov khoom siv hluav taws xob sab nraud, thermal shock resistance, mechanical tev kuj, thiab ua tau raws li ntau yam kev siv hluav taws xob nruj;

(12) Kev nyab xeeb thiab kev tiv thaiv ib puag ncig ntawm tus number case: PCB number case yuav tsum muaj tshuaj lom neeg tsawg, tsis muaj ntxhiab, nyab xeeb thiab ib puag ncig zoo.

Saum toj no peb tau sau cov ntsiab lus ntawm kaum ob PCB inks. Ntawm lawv, hauv kev ua haujlwm tiag tiag ntawm kev tshuaj ntsuam luam ntawv, qhov teeb meem ntawm viscosity yog ze rau tus neeg teb xov tooj. Lub viscosity tseem ceeb heev rau qhov smoothness ntawm silk screen. Yog li ntawd, nyob rau hauv PCB number case technical ntaub ntawv thiab qc cov ntaub ntawv, lub viscosity yog kom meej meej cim, qhia nyob rau hauv dab tsi tej yam kev mob thiab hom viscosity xeem ntsuas yuav siv. Hauv cov txheej txheem luam ntawv tiag tiag, yog tias tus number case viscosity siab dhau lawm, nws yuav nyuaj rau luam tawm, thiab cov npoo ntawm cov duab yuav raug jagged hnyav. Txhawm rau txhim kho cov txiaj ntsig luam ntawv, lub thinner yuav muab ntxiv kom cov viscosity ua tau raws li qhov yuav tsum tau ua. Tab sis nws tsis yog qhov nyuaj kom pom tias ntau zaus, txhawm rau kom tau txais qhov kev daws teeb meem zoo tshaj plaws (kev daws teeb meem), txawm li cas los xij koj siv viscosity, nws tseem ua tsis tau. Vim li cas? Tom qab kev tshawb fawb tob, kuv pom tias tus number case viscosity yog qhov tseem ceeb, tab sis tsis yog tib qho xwb. Muaj lwm qhov tseem ceeb tshaj plaws: thixotropy. Nws tseem cuam tshuam rau kev luam ntawv raug.

Plaub. Thixotropy

Viscosity thiab thixotropy yog ob lub tswv yim sib txawv ntawm lub cev. Nws tuaj yeem nkag siab tias thixotropy yog ib qho cim ntawm kev hloov pauv ntawm tus lej viscosity.

Thaum tus number case nyob ntawm qhov kub thiab txias, piv txwv tias cov kuab tshuaj hauv tus number case tsis evaporate sai, lub viscosity ntawm tus number case yuav tsis hloov lub sijhawm no. Lub viscosity tsis muaj dab tsi cuam tshuam nrog lub sijhawm. Lub viscosity tsis yog qhov sib txawv, tab sis qhov tas li.

Thaum tus number case raug rau sab nraud quab yuam (stirring), viscosity hloov. Raws li lub zog txuas ntxiv mus, lub viscosity yuav txo qis, tab sis nws yuav tsis poob mus ib txhis, thiab nres thaum nws ncav cuag ib qho kev txwv. Thaum lub zog sab nraud ploj mus, tom qab qee lub sijhawm ntawm kev sawv, tus number case tuaj yeem maj mam rov qab mus rau qhov qub qub. Peb hu cov khoom no rov qab los ntawm lub cev uas tus number case viscosity txo qis nrog lub sijhawm txuas ntxiv raws li qhov kev txiav txim ntawm sab nraud quab yuam, tab sis tom qab lub zog sab nraud ploj mus, nws tuaj yeem rov qab mus rau qhov qub viscosity li thixotropy. Thixotropy yog lub sijhawm muaj feem cuam tshuam nrog kev ua haujlwm ntawm lub zog sab nraud.

Nyob rau hauv qhov kev txiav txim ntawm sab nraud quab yuam, lub sij hawm luv luv ntawm lub zog, thiab qhov pom tseeb txo qis hauv viscosity, peb hu rau tus cwj mem no lub thixotropy loj; ntawm qhov tsis sib xws, yog tias qhov viscosity txo qis tsis pom tseeb, nws tau hais tias thixotropy me me.

5. Cov tshuaj tiv thaiv kab mob thiab kev tswj cov kua nplaum thixotropy

Dab tsi yog thixotropy? Vim li cas cov viscosity ntawm tus number case txo qis nyob rau hauv qhov kev txiav txim ntawm sab nraud quab yuam, tab sis sab nraud quab yuam ploj, tom qab ib lub sij hawm ntawm lub sij hawm, tus thawj viscosity yuav rov qab los?

Txhawm rau txiav txim siab seb tus number case muaj qhov tsim nyog rau thixotropy, thawj zaug yog cov resin nrog viscosity, thiab tom qab ntawd tau sau nrog qee qhov ntim piv ntawm cov muab tub lim thiab cov xim xim. Tom qab cov resin, fillers, pigments, additives, thiab lwm yam yog hauv av thiab ua tiav, lawv yog heev uniformly tov ua ke. Lawv yog cov sib tov. Thaum tsis muaj hluav taws xob sab nraud lossis lub teeb ci ultraviolet, lawv muaj nyob ua ib pawg ion tsis tu ncua. Nyob rau hauv ib txwm muaj xwm txheej, lawv tau npaj kom muaj kev sib haum xeeb vim muaj kev sib koom ua ke, qhia txog lub xeev siab viscosity, tab sis tsis muaj tshuaj lom neeg tshwm sim. Thiab thaum nws raug rau sab nraud mechanical quab yuam, qhov kev txiav txim thawj zaug raug cuam tshuam, kev sib nrig sib txuas saw raug txiav tawm, thiab nws dhau los ua lub xeev tsis zoo, uas qhia tias qhov viscosity qis dua. Qhov no yog qhov tshwm sim uas peb feem ntau pom tus number case los ntawm tuab mus rau nyias. Peb tuaj yeem siv cov txheej txheem kaw rov qab rov qab los ua kom pom tseeb ntawm tag nrho cov txheej txheem ntawm thixotropy.

Nws tsis yog qhov nyuaj kom pom tias cov khoom khib nyiab hauv tus number case thiab cov duab thiab qhov loj ntawm cov khib nyiab yuav txiav txim siab txog cov khoom thixotropic ntawm tus number case. Ntawm chav kawm, tsis muaj thixotropy rau cov kua dej uas muaj qhov muaj viscosity tsawg heev. Txawm li cas los xij, txhawm rau ua kom nws mus rau hauv tus cwj mem thixotropic, nws yog technically tau ntxiv tus neeg sawv cev pab hloov thiab ua kom cov viscosity ntawm tus number case, ua rau nws thixotropic. Cov tshuaj ntxiv no hu ua tus neeg sawv cev thixotropic. Yog li ntawd, thixotropy ntawm tus number case yog tswj tau.

Rau. Kev siv tswv yim ntawm thixotropy

Hauv kev siv tswv yim, nws tsis yog qhov ntau dua qhov thixotropy, qhov zoo dua, lossis qhov me dua qhov zoo dua. Nws tsuas yog txaus. Vim nws cov khoom thixotropic, tus number case yog heev haum rau cov txheej txheem ntawm kev tshuaj ntsuam luam ntawv. Ua rau lub vijtsam luam ntawv ua haujlwm yooj yim thiab dawb. Thaum lub sij hawm tus cwj mem luam ntawv luam ntawv, tus cwj mem ntawm lub vas yog thawb los ntawm lub squeegee, dov thiab squeezing tshwm sim, thiab viscosity ntawm tus number case yuav qis dua, uas yog qhov zoo rau tus cwj mem nkag. Tom qab tus cwj mem tau tshuaj ntsuam luam tawm ntawm PCB substrate, vim tias qhov viscosity tsis tuaj yeem rov qab tau sai, muaj qhov chaw tsim nyog los ua kom tus number case ntws maj mam, thiab thaum qhov sib npaug rov qab, cov npoo ntawm lub vijtsam luam tawm cov duab yuav tau txais kev txaus siab. flatness.