ONESEINE flex and rigid PCB thickness design and reinforcement strategy: unlock the key code of electronic manufacturing

ONESEINE flex and rigid PCB design and reinforcement strategy: unlock the key code of electronic manufacturing

Soft and hard PCB, combining the advantages of soft and hard boards, plays an important role in the manufacture of electronic equipment. Its design is very different from ordinary soft or hard boards, and special attention should be paid to the following key points.

1. Key points of flexible partition line design

1. Thick and thin line transition: To prevent the line from being damaged due to sudden expansion or contraction, the connection between thick and thin lines should be designed to be torn to avoid sudden changes in lines.

2. Corner processing: Use smooth corners to avoid sharp corners to ensure the stability and reliability of the line.

2. Gasket and pad design specifications

The size of the gasket should be maximized as much as possible while meeting the power transmission requirements.

The transition line of the pad and the wire connection part needs to abandon the right-angle design and adopt a smooth transition method.

Independent pads should be set with solder toes to enhance the support effect and improve the firmness of welding.

3. Dimensional stability guarantee strategy

In the design, copper parts should be added, especially in the waste area, and more solid copper berths should be planned to reduce the risk of deformation and improve the dimensional stability of the entire rigid-flexible PCB.

4. Tips for laminating window design

Manual alignment hole setting: Adding manual alignment holes can significantly improve the alignment accuracy during the laminating process and ensure the accuracy of the production process.

2. Window size considerations: The window design needs to fully consider the glue flow range. Generally speaking, the window opening should be slightly larger than the original design, and the specific size depends on the design standards provided by ME.

3. Special window opening mold: For small and dense window opening requirements, special mold designs such as rotating punches and jumping punches can be used to achieve precise processing.

5. Key points of rigid deflection transition zone design

1. Line transition requirements: The lines need to achieve smooth transition in the transition zone, and the line direction should be perpendicular to the bending direction to ensure the normal operation of the line during the bending process.

2. Wire distribution principle: The wires should be evenly distributed in the entire bending area to avoid local concentration or sparseness.

3. Wire width and process restrictions: The wire width should be maximized in the bending area as much as possible. At the same time, PTH design, Coverlay and non-flow PP design are strictly prohibited in the transition area to prevent affecting the bending performance.

VI. Design rules for flexible areas with air gap requirements

1. Through-hole restrictions: It is strictly prohibited to set through-holes in the part that needs to be bent in the flexible area to prevent damage to the line during bending.

2. Protection copper wire setting: If space permits, protection copper wires should be added on both sides of the line; if space is insufficient, protection copper wires can be added at the inner R angle of the bending part.

3. Line connection shape: The connection part of the line should be designed as an arc to meet the bending requirements.

4. Bending area optimization: Without affecting the product assembly, the larger the bending area, the better the effect.

VII. Other key considerations

Tool holes of soft boards, such as punching, ET, SMT positioning holes, etc., are strictly prohibited from being shared to avoid affecting accuracy and performance.

8. Full analysis of FPC reinforcement materials

FPC (flexible circuit board) is widely used in electronic products, but due to its low mechanical strength and easy cracking, it often needs to be combined with reinforcing materials to improve strength. Common FPC reinforcement materials are as follows:

1. PI reinforcement: The tolerance can be accurately controlled within ±0.03mm, with high precision and good high temperature resistance (130°C - 280°C). Its thickness specifications are rich, including 0.075mm, 0.1mm, 0.125mm, 0.15mm, 0.175mm, 0.2mm, 0.225mm, 0.25mm.

2. Steel plate reinforcement: This method requires manual assembly, the operation is more complicated, and the cost is higher. The thickness of steel plate reinforcement is generally 0.1mm and 0.2mm.

3. FR4 reinforcement: When the thickness is less than 0.1mm, the tolerance can be controlled within ±0.05mm; when the thickness is 1.0mm, the tolerance is ±0.1mm. The thickness specifications are 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, and 1.6mm.

Each reinforcement material has its own advantages and disadvantages: PI has a small tolerance but insufficient hardness, FR4 has a larger tolerance when it is thicker, and the steel plate is hard but difficult to rework. In practical applications, it is necessary to select a suitable reinforcement solution according to specific needs.