4 Layer Flex PCBs

Flex PCBs can support a wide range of layer counts depending on the manufacturing process. SFX PCB produces flex PCBs with up to 8 layers in low-volume production, while rigid-flex configurations support up to 20 total layers. Mass production typically focuses on single and double-panel configurations for cost efficiency.

Yes, flex PCBs can absolutely be multilayer. SFX PCB manufactures multilayer flexible circuits with up to 8 layers on polyimide substrates, supporting advanced features like laser drilling down to 4mil, impedance control of ±10%, and inner layer line widths as fine as 2.5mil/2.5mil for high-density designs.

SFX PCB offers a comprehensive range of surface finishes including ENIG (Electroless Nickel Immersion Gold), OSP, HASL, Immersion Silver, Immersion Tin, ENEPIG, Soft Gold, and Hard Gold Plating. The choice of finish depends on solderability requirements, shelf life, application environment, and whether the board is used in high-wear connector areas.

4 layer flex PCBs are used across aerospace, defense, medical devices, automotive systems, industrial automation, telecommunications, and consumer electronics. Their ability to bend, fold, and fit into complex three-dimensional enclosures makes them ideal for hearing aids, X-ray equipment, avionics, radar systems, ABS controllers, and wearable technology.

SFX PCB's flexible PCBs are manufactured under ISO 9001:2015 and ISO 14001:2015 quality management systems, and the facility holds ISO 13485 certification. Multilayer rigid-flex products meet IPC Class II standards. All boards undergo two-factor quality control combining visual and optical inspection, along with electrical testing, impedance testing, and solderability testing prior to shipment.

In low-volume production, SFX PCB achieves laser drilling down to 4mil, inner layer line width/space of 2.5mil/2.5mil, outer layer line width/space of 3mil/3mil, and BGA pitch as fine as 0.15mm. Board outline tolerance is held to ±0.025mm, enabling highly precise, dense circuit designs for miniaturized electronic products.

SFX PCB provides a detailed stack-up review and competitive quote within 8 business hours of submitting your PCB files and specifications. Prototype assembly is available from 24 hours, making it possible to move from design submission to a working prototype very rapidly for time-sensitive projects.