Design robots with rigid PCB board without consideration of protecting the PCB from vibration failures caused by mechanical resonance. These failures can lead to serious problems such as broken insulators and capacitors, component disconnections, PCB wiring discontinuities, solder spot cracks, PCB board layering, electrical short circuits and disconnection of plating barrel to pad. To eliminate these failures, flexible rigid printed circuit boards are required.

What is rigid flexible PCB?

A printed circuit board in which rigid and flexible circuit plates are laminated together to weld parts on rigid parts and bend parts instead of wired connections. The rigid part can be like a traditional rigid PCB, where the components can be welded on both sides of the board and multiple layers of connections can be made, while the flexible part can be connected in multiple layers, but the components can be welded on it because the flexible part is used to connect only between the rigid circuit parts.

Eliminating connectors from the design introduces the following properties to the circuit: Transmission of signals from one part to another without loss or jitter (noise) Eliminate connection problems such as cold contacts .Free up space and reduce weight. Makes the circuit vibration-proof and can be installed in applications with moving parts.

Design rigid flexible PCB:

A variety of software is available for designing rigid flexible PCBS, but Altium provides the best 3D visualization of rigid flexible PCBS and is highly recommended. When designing the rigid and flexible parts, it is most important to select the copper trace width according to the application.

This indicates that the same amount of current must be used in the rigid and curved parts with different trace widths due to the thickness, area and permittivity of the material. Rayming PCB and Assembly engineers are always available to consult on the correct wiring width and favorable material for your operating frequency and application.

Simulation of flexible PCB:

Paper doll prototype is very important in designing flexible circuits. This simple practice can help designers prevent many errors by showing problems related to bending early, and can save time and money. This helps the designer predict the bending radius and choose the right direction for the copper trace to prevent tearing or discontinuity.

Design copper trace with bias:

Keeping extra copper in the design increases the dimensional stability of the flexible circuit. For single-layer and double-sided flexible designs, biasing around the copper trace is a good practice. The addition or removal of additional copper depends only on the application, but if the designer has additional copper with bias, traces with bias should preferably be used for mechanical stability. In addition, doing so can reduce the amount of copper etched, which is environmentally friendly in terms of chemical use.

What is rigid flexible PCB and how to design rigid flexible PCB? Huaqiang PCB

Binding structure in multi-layer flexibility:

Staggered length design is usually used to facilitate the design of multi-layer flexible circuits. In this technique, the designer slightly increases the length of each subsequent flexible layer, which is typically 1.5 times the thickness of the individual layer. This prevents center bending of a curved layer in a multi-layer flexible circuit with a separate layer. By this simple method, the tensor strain and i-beam effect established on the outer metal layer can be eliminated, which may be a key problem in dynamic applications.

What is rigid flexible PCB and how to design rigid flexible PCB? Huaqiang PCB

Track corner wiring:

Some of the problems associated with wire routing in flexible circuits include keeping the number of crossings to a minimum so that layers can be reduced to save money, and the second is the bending Angle of traces in flexible circuit design. Traces should be bent and folded around corners, as sharp corners can trap solution during etching and may overetch and will be difficult to clean after treatment. When there are copper traces on either side of a flexible circuit, the designer should design a space of 2-2.5 times the line width to avoid any electrical short circuit and appropriate etching. Considering these commands can improve signal propagation and reduce reflections during turns.

What is rigid flexible PCB and how to design rigid flexible PCB? Huaqiang PCB

Rigid bending transition part:

The minimum distance from the rigid to flexible transition zone to the edge of the clearance hole and plated through hole shall not be less than 0.0748 inches. When designing the distance between the non-plated through hole and the inside and outside edges of the cut, the final residual material should not be less than 0.0197 inches.

Rigid – flexible interface coating through hole:

The recommended minimum distance between the rigid cross section and plated through holes of the rigid flexible interface is greater than 0.125 in. Violation of this rule may affect the reliability of the plating through hole.