PCBA will appear white around the pads after soldering, which will generally occur after PCBA wave soldering, PCB cleaning machine, storage and maintenance.
Cov tshuaj dawb no feem ntau yog residues los ntawm.
1. yoj crest nto ntab nrog nyias daim tawv nqaij ntawm tin oxide.
2. preheating kub lossis nkhaus tsis tsim nyog.
3. flux ntws yog siab dhau lawm, preheating kub yog tsawg, noj tin lub sij hawm luv heev.
4. flux muaj pes tsawg leeg, xyuas qhov kev xeem thiab ntawv pov thawj.
1. Rosin nyob rau hauv lub solder.
Feem ntau ntawm kev tu tsis huv, tom qab khaws cia, tom qab tsis ua haujlwm ntawm cov pob qij txha ntawm cov khoom siv dawb, muaj nyob hauv cov flux nws tus kheej rosin.
2. Rosin denatured khoom.
Qhov no yog lub rooj tsavxwm nyob rau hauv cov txheej txheem ntawm vuam, rosin thiab solder generated los ntawm cov tshuaj tiv thaiv ntawm cov khoom, thiab solubility ntawm cov khoom no feem ntau tsis zoo, tsis yooj yim rau ntxuav, lingering ntawm lub rooj tsavxwm, tsim ntawm dawb residue.
3. Organic hlau ntsev.
Lub hauv paus ntsiab lus ntawm kev tshem tawm cov welding nto oxide yog cov organic acid thiab hlau oxide cov tshuaj tiv thaiv los tsim cov hlau ntsev soluble hauv cov kua rosin, tom qab txias thiab rosin los ua ib qho kev daws teeb meem, tshem tawm nrog rosin hauv kev tu.
4. Hlau inorganic ntsev.
Cov no tej zaum yuav yog hlau oxides nyob rau hauv lub solder thiab flux los yog solder paste nyob rau hauv lub halogen - muaj active tus neeg saib xyuas, PCB solder tais nyob rau hauv lub halogen ion, residual halogen ion nyob rau hauv lub Cheebtsam txheej txheej, FR4 cov khoom uas muaj halogen khoom tso tawm ntawm Qhov kub thiab txias thaum cov tshuaj tiv thaiv tsim los ntawm halogen ion, kev solubility hauv cov kuab tshuaj organic me me heev. Yog tias lub tshuab ntxhua khaub ncaws raug xaiv kom tsim nyog, cov khoom seem yuav raug tshem tawm; ib zaug cov tshuaj ntxuav tau raug xaiv thiab cov khoom seem tsis sib xws, nws yuav nyuaj rau tshem tawm cov ntsev ntsev, yog li tawm cov pob dawb ntawm lub rooj tsavxwm.
PCBA soldering tom qab lub ncoo yog dawb, feem ntau yog flux residue, ntxuav tsis huv los ntawm qhov yuav tsum tau ntxuav tom qab vuam.
