1. The through-hole plug-in components are arranged in disorder.
2. The polarity direction consistency is not good.
3. The pin arrangement of the light-weight components is parallel to the direction of the wave soldering board, and the horizontal component floats and lifts due to the asymmetric heat of the pins.
4. The pitch between the components is too small: less than 0.75mm.
5. The pin forming span is less than 2.54mm.