First of all, the main role of HAL:
①Control the surface oxidation of bare copper
Second, there are two types of spray tin: vertical and horizontal HAL HAL. And vertical spray tin has the following main disadvantages.
①Uneven heating up and down of the board, last in first out, and curling defects of easy-bend plates.
②The thickness of the pad is uneven, because the hot air force and gravity lower the tinplate produced by the pad. Therefore, SMT soldering surface mount parts are not easy to stick and stabilize, which is convenient for post-welding parts to offset or monument legislation.
③The contact time of the solder between the board and the wall is longer than the bare copper pad, generally more than 6 seconds. The copper volume of the furnace is faster in the solder, and the increase in the copper content will directly affect the pad, because the thickness is produced. The thickness of the alloy layer greatly reduces the shelf life of the board, and the level of HAL significantly overcomes these shortcomings.
Compared with vertical tin spraying, it has the following advantages.
①The contact time between molten tin and bare copper wire is short, about 2 seconds, the thickness is thin, and the shelf life is long.
②Wetting time, short wetting time, about 1 second.
③The board is heated evenly, maintains good mechanical properties, and the board is less arbitrarily.
XPCB Limited is a manufacturer specializing in the production of high-precision double-sided, multi-layer and impedance, blind buried vias, and thick copper circuit boards. The products cover HDI, thick copper, backplanes, rigid-flex combined, buried capacitance and buried resistance, Golden Finger and other types of circuit boards, which can meet the needs of customers for various products.
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