Flex PCB is a typical term that is synonymous with flexible circuits. While the term “PCB” is normally used to describe stiff printed wiring, “flex PCB” is a little inconsistent since “boards” aren’t truly flexible. Some companies, like All Flex, design and also produces flex PCBs, yet not rigid PCBs.
There are lots of resemblances between both, however additionally substantial distinctions.
Design
The fastest distance between two points is a straight line, so a circuit trace on a flex circuit should resemble a circuit trace on a rigid motherboard, right? Actually there could be considerable differences between designing a rigid PCB and also a flexible PCB. Because of the versatility attribute, there are one-of-a-kind concerns influencing robustness. For instance, because flex can bend, one needs to be sure that bending does not split or break solders joints near a bend location. Therefore, design functions like radiused edges as well as filleted pads prevail on flexible circuits. One more problem is that the substratum utilized for flex is not as dimensionally stable vs. its inflexible relative. Allowances for dimensional adjustments could be needed for flexible PCB design. A lot of PCB design software program is tailored to stiff printed circuit products and also attributes. Tradeoffs occur when this same software program is used to design flexible PCB.
Tooling
Both PCB and flex PCB usage similar tooling such as CAD files, photo devices and also electric examination fixtures. Possibly the biggest distinction is around the cutline meaning. Flexible circuits provide unlimited arrangement possibilities that often results in extremely weird sizes and shapes. Circuit boards usually are rectangle-shaped or could have some notches or bent lays out routered. As a result of this subtlety, steel rule passes away as well as difficult device passes away are most likely utilized regularly for flex PCBs than for boards, at the very least for ultra-high-volume applications. Laser interpretation of the circuit overview is likewise a typical flex PCB procedure. Various other differences in tooling involve fixturing that could be needed to take care of flexible substratums.
Manufacturing
Stiff PCB as well as flex PCB have extremely similar manufacturing steps and commonly use the same devices as well as tools manufacturers. For instance, photo imaging the base circuitry layer can make use of practically the same modern technology. The distinctions occur because of the difference in between managing a stiff board versus a flexible substratum. Some ultra-thin circuits are extremely flimsy and need unique material managing systems. While a PCB is fairly simple to deal with, a slim flexible circuits could require special securing, fixturing or vacuum systems to hold it in position while handling. Some extremely high-volume flex PCB produces process circuits in a continuous reel (reel-to-reel). Reel to reel processing uses substantially various material handling systems vs. systems processing distinct panel sizes.
Coverlay/Covercoat
Flex PCB requires different dielectric materials such as flexible photoimagable soldermask or laminated coverlay (likewise called coverfilm) vs. the non-flex PCB. This creates products with unique residential properties as well as difficulties. Materials have to bend as well as flex, with some applications calling for numerous cycles, without breaking or peeling. Several design attributes need to be thought about with dynamic flex applications, including: copper grain direction, circuit pattern layout, coverfilm density, as well as trace geometries. One of the most usual flexible dielectric is laminated film dielectric adhered to the substratum with heat and stress, a remedy rarely made use of for stiff PCB.
Applications
Flex PCB make up about 10-15% of all PCB manufacturing generate around the world, so there are much more applications that utilize hard boards compared to flex. The most significant benefit for flex PCB is that it could decrease the dimension, weight and also quantity of equipment used for many electronic bundles. It is ideal called an “digital adjoin packing solution.” The principle of an “origami flexible circuits” likewise comes to mind. If you have an application that calls for several airplanes of interconnections, or there are energetic bending or bending requirements for components of the bundle, after that a flex PCB could be your best choice.