Issue link: https://iconnect007.uberflip.com/i/1042925
52 FLEX007 MAGAZINE I OCTOBER 2018 One of the biggest challenges with flex cir- cuits in assembly is flatness. Flex circuits are thin and flimsy and getting them to lie flat is always a challenge. The assembler needs this flatness to apply solder paste, place the compo- nents, and properly solder those components. Often, the flex circuits need to be attached to a carrier plate to keep them flat enough to pro- cess. A backup fixture is sometimes created to carry the circuits through the pick-and-place process. For assemblers who are not familiar with flex circuits, flatness will be their biggest learning curve. Handling is critical when dealing with flex circuits—not just during assembly, but through the entire manufacturing process. Handling is important from the beginning of flex circuit manufacturing through to the final installation of the flex circuit. Bend radius regions need to be handled with care. Areas where through- hole components are installed need to be han- dled properly to eliminate opportunities for damage. Mishandling can easily tear the flex circuit or crack copper traces. Most flex cir- cuits will naturally have an odd shape and will need to be put in an array for ease of handling through assembly (Figure 5). The flex circuit will be processed in the array and ship to the end customer in array form. The flex circuit should not be removed from this array until the final installation. Conclusion As electronic products become smaller, flex circuits will become more popular and com- mon in the electronics industry. Due to the complexity of a flex circuit—including the material cost, processing time, chemistry, drill- ing, and handling—the cost to fabricate a flex board is higher than a traditional rigid board. Although the cost is higher, there are many useful applications for flex circuits. Flex cir- cuits allow designers to expand their imagina- tions and develop more innovative electronic products. With the ability to move back and forth in a dynamic environment, flex circuits have allowed the electronics industry to be more flexible. FLEX007 Tuan Tran is director of customer engagement at Green Circuits, a full-service contract manufacturer for the EMS industry. Figure 5: Odd-shaped flex circuits in panel array for ease of assembly.