PCB industry can be divided into three categories: rigid printed circuit board, soft printed circuit board and board. Soft printed circuit boards and plates are emerging industries, with only rigid PCB in the early stages of history. Despite the rapid growth of soft printed circuit boards and substrates in recent years, rigid PCB still occupies 50% of the industry. Rigid PCB There are also many rigid PCB suppliers are not less than the flexible printed circuit boards and substrates, the profit margin.
PCB industry is quite mature, the growth rate generally not exceed 6%. The output of rigid PCB manufacturers has been declining for a long time, and when the smartphone and tablet market showed surprisingly rapid growth in 2012, rigid printed circuit board suppliers experienced very difficult times. Rigid PCB manufacturers into a fierce price war, resulting in profit and income decline. At the same time, large-scale PCB companies believe that the traditional rigid printed circuit board has not enough growth potential, Rigid PCB so they began to turn their attention to soft printed circuit boards and substrates. In 2013, almost all of China's rigid PCB manufacturers outside the mainland to return to profitability, 2014 profit margin also rose sharply.
In the future, large PCB suppliers will focus on soft printed circuit boards and substrates, for rigid PCB maintenance status.
Most of the design elements of rigid PCB have been applied in the design of flexible printed circuit board. However, Rigid PCB there are other new elements that need attention.
1. Carrying capacity of conductors
Because the thermal capacity of the flexible printed circuit board is poor (compared to that of a rigid printed circuit board), sufficient wire width must be provided. When the current is above 1A, the principle of selecting the wire width. When some conductors carrying large current are facing each other or adjacent to each other, the extra wire width or spacing must be given when considering the problem of heat concentration.
The rectangle should be preferred wherever possible, Rigid PCB because it can save the base material better. There should be enough free margins near the edge, depending on the possible residual space of the substrate.
On the shape, the inner angle should look round;
Smaller conductor widths and spacing should be minimized. If the geometrical space permits, the tightly arranged fine wires should be turned into wide wires. The wires terminated at the plated-through hole or the mounting hole of the component should be smoothed over to the solder plate, Rigid PCB as a general standard, any change from straight line to image angle or different line width must be as smooth as possible. The sharp angle causes the stress to concentrate naturally, causing the conductor to malfunction.
3. Degree of flexibility
As a general standard, the bending radius should be designed as large as possible. The use of thinner laminates (e.g., 50 copper foil instead of 125 copper foil) and wider wire can improve the likelihood of more cyclic bending. For a large number of bending cycles, single-sided flexible printed circuit boards usually show better performance.