In the layout, the circuit board size is too large, although the welding is easier to control, but the printing lines are long, the impedance increases, the anti-noise ability decreases, the cost increases, after the hour, the heat dissipation decreases, welding is not easy to control, easy to appear adjacent lines interference with each other, such as circuit board electromagnetic interference and so on.

Therefore, the PCB board design must be optimized:

(1) Shorten the connection between high frequency components and reduce EMI interference.

(2) A large weight (such as more than 20g) components shall be fixed with a bracket and then welded.

(3) Heating elements should consider the heat dissipation problem, to prevent the component surface has a large DELTA T defects and rework, thermal components should be away from the source of heat.

(4) The arrangement of components as parallel as possible, so that not only beautiful and easy to weld, it is advisable to carry out mass production. The circuit board is designed to be 4:3 rectangular best. The wire width does not mutate to avoid the discontinuity of wiring. When the circuit board is heated for a long time, copper foil tends to swell and fall off, so it should avoid the use of large area copper foil.