Introduction:
Traditional rigid-flex PCB materials include rigid materials and flexible materials. The current production method is usually to carry on the pattern plating for the rigid substrates and flexible substrates, and then laminating the rigid substrates and flexible substrates together by using the adhesion agent. The materials of the adhesion agent are usually made of non-flowing prepregs. Flexible materials are expensive and costly to make. At present, the cost of multilayer rigid-flex PCB is 5-7 times of that of the traditional multi rigid PCB, which limits the development of rigid-flex PCB.
At the same time, compared with the rigid materials, the changes of flexible materials which will always change with the change of the size are much bigger. The inconsistency of expansion and contraction may lead to the circuit patterns’ dislocation of the same size rigid materials and flexible materials when laminating, which will reduce the reliability of the products.
Semi-Flex PCB:
The most traditional manufacturing process of semi-flex PCB is adopting the bending FR-4 materials and making PCB according to the traditional rigid PCB manufacturing process, and then using the deep milling technology to thin the areas that need to be bended so that it has a certain degree of flexibility, so as to meet the requirements of assembly bending connection.
Main Characteristics of Semi-Flex PCB:
① Low Cost:
Semi-flex PCB technology, using epoxy resin FR-4 material, first in accordance with the normal process of PCB processing, and then through depth milling selectively reduce the thickness of the traditional multi-layer material, so that it has a certain degree of flexibility. Compared with the production of double-side PCBs and multilayer PCBs, this method only has one more manufacturing step, and the processing process is relatively simple. It can reduce the cost by replacing expensive polyimides and other flexible materials, and can significantly reduce the cost compared with flexible PCBs and traditional rigid-flexible PCBs.
② High Reliability:
The semi-flex PCB is used in the automotive and electronics industry, so it has strict requirements. When the final assembly requires the PCB board to stack, the semi-flex PCB can not only reduce the cost, but also reduce the welding point and the entanglement of connectors, with the characteristics of components can be mounted in the same state, the same plane. After the assembly is completed, the flexible part can meet the requirement of bending to the final shape without using the flexible substrate, which overcomes the reliability problem caused by inconsistent expansion and contraction of the flexible substrate and the rigid substrate, thus improving the reliability of the electronic product system.
③ Special Installation Performance:
Semi-flex PCB is a kind of PCB that can be locally bent on the basis of rigid PCB, which can not only provide the support of rigid PCB, but also achieve local bending according to product requirements, including the bending in 45゜, 90゜, 180゜, meeting the installation performance requirements of various types of 3D assembly, shown as below.
Conclusion:
Semi-flex PCB products are mainly used in automotive electronics, large machines, data communication and other fields, and can meet the requirements of high system reliability, low installation time, low installation cost and three-dimensional installation required by today's substrate installation interconnection to the greatest extent. On the basis of the rigid PCB, through special processing method, realizes the partial flexible performance. Compared with the traditional sense of the rigid-flex PCB, semi-flex PCB has not only significantly reduced on the material cost, manufacturing cost and the difficulty of manufacturing process, but also can satisfy the requirement of local bending installation of a certain number of times. At the same time, semi-flex PCB can provide a more stable, complete electrical signal transmission performance, which can partially replace some application of the rigid-flex PCBs. The application of semi-flex PCB will be greatly promoted under the background of the rapid development of rigid-flex PCB market.
