av不卡网免费日韩精品黄色无码,国产成人黄色网站中文一区无码在线,欧美日韩片区域网站,欧美国产内射XXX草

For lead-free soldering temperature selection should take into account the thickness of the PCB board, whether the size of the pad, the device and the surrounding area have a greater cooling, suggest that the use of conventional solder temperature is selected around 350 ℃, to meet the requirements of the situation in the size of the tip of the election as much, because the larger the tip, the greater the heat capacity, the temperature can be set lower, the less heat loss. In this case the relative increase welding speed will ensure the quality of welding.