Most rigid PCB design elements have been applied in the design of a flexible PCB . However, there are some other new elements that require attention .
1 current carrying capacity of the wire
Since the flexible PCB heat capacity difference ( compared to rigid PCB purposes ) , it is necessary to provide sufficient wire width . Some wires carrying large currents or adjacent to each other when placed face to face , considering the heat concentration problems , must be given an extra wire width or spacing.
2 Shape
No matter where in the case of possible rectangle should be preferred , because it can save a good base . Near the edge of freedom should allow sufficient margins , depending on the substrate may be the remaining space .
In shape , rounded angles should look ; pointed angles may cause the tear panel .
Smaller conductor width and spacing should be minimized as much as possible . If the geometric space permits, should be tightly packed into a thin wire width wire. Plated through holes in the wire or component mounting holes at the termination of the search to be smoothly over pads . As a general standard , any necessary transition as smooth as the angle from straight or change to a different line widths . Sharp natural causes stress concentration caused by lead failure .
3 . Flexibility
As a general standard , the bending radius should be designed to be as large as possible . The use of thinner laminates ( eg: 125μm 50μm copper foil instead of the wire and a wider , it can better withstand more improved possibilities for large cyclic bending of bending cycles , single-sided flexible PCB is usually displayed . better performance .
4 pads
Around the pad , there is a change from a flexible material to a rigid material. This area of the conductor more easily damaged . Therefore , the pad should be avoided in the area prone to bending . The general shape of the pad should be such as teardrop-shaped , film must be able to cover the bonding pad seam.
5 . Rigid reinforcing plate
In the small electronic devices ( such as a small calculator ) in mass production , in combination with rigid laminates reinforced flexible PCB seizure board has become very popular, but it is also more cost optimization . Flexible PCB is equipped with a suitable slot in a rigid plate ( eg grade G-10) on to facilitate future separation. After assembling and soldering components connected by cutting the rigid plate into different parts, so as to be folded into the shape you want.
