How to choose reinforcement board of flexible circuit board
Jing Guan Ying FPC
In order to meet the use environment and installation environment of FPC, it is usually necessary to select a suitable reinforcement board to strengthen the FPC partially or entirely during the design of the flexible circuit board. Commonly the FPC reinforcing plates are PI, polyimide reinforcing plate, FR-4 glass fiber reinforcing plate and 303 stainless steel sheet reinforcing plate. And the reinforcing plate of each material has different thickness. How to choose the reinforcement board of the flexible circuit board is one of the important links that affect the effectiveness of the flexible circuit board.
The material used for FPC reinforcement generally needs to meet the properties of high temperature resistance, acid and alkali corrosion resistance, and high temperature resistance. Then, Shen Zhen Jing Guan Ying Electronics Co., Ltd will introduce the characteristics of various FPC reinforcement boards for you, so that you can better understand the various reinforcement boards and choose the appropriate reinforcement board.
1. Polyimide reinforcing plate, namely Polyimide, abbreviated as PI
Polyimide reinforcement board, namely Polyimide, abbreviated as PI. As a special engineering material, polyimide has been widely used in aviation, aerospace, microelectronics, nano, liquid crystal, separation membrane, laser and other fields. Recently, all countries are listing polyimide research, development and utilization as one of the most promising engineering plastics in the 21st century. Because of its outstanding characteristics in terms of performance and synthesis, whether it is used as a structural material or as a functional material, its huge application prospects have been fully recognized, and it is called a "protion solver" (protion solver), and It is believed that "without polyimide there would be no microelectronic technology today." It has flame retardancy, high temperature resistance and low temperature resistance. The fourth-generation PI products used today have a long-term use temperature of -200 ℃ ~ 426 ℃, and its mechanical properties are not high, but after adding fiber synthesis, the mechanical properties are extremely high. High, carrying creep, self-lubricity, wear resistance, radiation resistance, and high insulation. These advantages make it shine in the electronics industry. In the production of FPC, the PI used is mainly PI protective film and PI reinforcing film. The thickness of the PI protective film is mainly 12.5um and 25um, which is used as circuit insulation; PI reinforcement board is mainly used in the area of the back of the FPC gold finger. On the one hand, it is to thicken the area to the corresponding connector's insertion height, making it Tightening, the second is its self-lubricating characteristics, making its surface smooth and not high in hardness, which greatly reduces the friction damage to the plugging area, and another thick FPC plugging and unplugging, it still maintains beautiful, three It is its low thermal expansion coefficient and high dimensional stability that make FPC reinforcement precision higher. The thickness of PI reinforcement sheet is mainly 0.1mm, 0.125mm, 0.15mm, 0175mm, 0.2mm, 0.225mm, 0.25mm. According to the design drawings and use environment, choose PI reinforcement with different thickness for pressing.
2.FR-4 itself is a flammable material grade.
In FPC, it often refers to an epoxy glass fiber cloth laminate with a FR-4 flame resistance grade. We directly refer to this material as FR4. Its mechanical properties, dimensional stability, impact resistance, and moisture resistance are higher than paper substrates. It has excellent electrical performance, higher operating temperature, and its performance is less affected by the environment. In processing technology, it has great advantages over other resin glass fiber cloth substrates. This type of product is mainly used for double-sided PCBs, and the amount is large. In FPC, it is mainly used as a reinforcing sheet, and it is mainly used as the back of the FPC welding area to strengthen the hardness of the welding area and protect the electronics after the patch. The components are not bad due to the continuous bending and extension of the FPC, and because their wear resistance is not comparable to PI, they generally do not need to be reinforced with gold fingers. In addition, it is also used as a mechanical fixing area, such as the installed card shell part. The thickness of FR4 used by FPC is mainly 0.15mm, 0.20mm, 0.225mm, 0.25mm, 0.275mm, 0.30mm, 0.4mm, 0.5mm, 0.8mm, 1mm, etc., also choose different FR4 according to different needs.
3. Steel sheet reinforcement board
Steel sheet reinforcement mainly refers to 303 stainless steel reinforcement. 303 stainless steel is an austenitic free-cutting stainless steel containing sulfur and selenium. It is used in occasions requiring free cutting and high surface finish. FPC reinforcement is often in different shapes, and stainless steel 303 is easy to etch. Therefore, in FPC products that require high stability, this type of steel sheet reinforcement is often used. Because the steel sheet reinforcement cannot be drilled with CNC or cut with an FPC laser, it is mainly made by the method of potion etching. The cost is relatively high. The thickness of FPC steel sheet reinforcement is generally 0.1mm, 0.15mm, 0.2mm.
Through the above introduction of Shenzhen Jingwanying Electronics, we can learn that when we select the appropriate reinforcing board for the flexible circuit board, we need to combine the actual needs and standards of the flexible circuit board. Choosing the appropriate reinforcement board can ensure the flexibility of the flexible circuit board, the reliability of electronic component assembly, the local hardness of the circuit board, and also the maximum possible space and cost savings.
Regarding the choice of flexible circuit board reinforcement board, Shenzhen Jingwanying Electronics Co., Ltd. welcomes the fields friends to call and consult Manager Liu:
Tel: 138 0962 9365