The effect of the wiring of the pad connection and the position of the pores on SMT production:

　　The wiring of the pad connection and the position of the pores has a great impact on the welding rate of SMT, because the inappropriate pad pad connection line and the pores may play the role of "theft" solder. Walk (the rainbow suction and capacity in the fluid). The following situation is good for production quality:

　　1. Reduce the width of the pad connection line:

　　If there is no current bearing capacity and limitation of PCB manufacturing dimensions, the maximum width of the pad connection line is 0.4mm or 1/2 pile width, which can be smaller.

　　2. The most preferably selected between the pads connected to the large -scale conductivity belt (such as ground floor, power surface) is a narrow connection line with a length of not less than 0.5mm (the width is not greater than 0.4mm or the width is not greater than 1/2).

　　3. Avoid introducing pads from the side or corner. The most preferably enter the middle of the connection line from the middle of the pad.

　　4. Try to avoid being placed in the pad in the SMT component or near the pad.

　　The reason is that the pores in the pad will attract the solder into the hole and leave the solder away from the solder joint; the holes directly close to the pads, even if there is intact green oil protection (in actual production, the green oil printing in PCB is inaccurate in the materials in the ingredients of PCB. There are many cases), and it may also cause heat sinking effects. It will change the infiltration speed of the welded joints, leading to a monument phenomenon in the chip component, which will hinder the normal formation of the welding joint.

　　The most optimal connection between the pores and the pads is a narrow connection with a length of not less than 0.5mm (the width is not greater than 0.4mm or the width is not greater than 1/2 pad width)