The purpose of the instant invention is to provide a superfine carbon fiber thread with excellent bending strength and repeated bending. To achieve this purpose, (1) a desired composite thread is produced by opening open carbon fibers, slitting the opened fibers, twisting the slit fibers and forming a composite with a composite thread; and (2) a composite thread is produced by performing a lamination process with a film (film of composite materials) while performing a fiber-opening process, and then slitting, twisting and heating the tread for stress relief.

An apparatus for manufacturing a guitar string includes a table part; a holding part holds both ends of a first wire so that the first wire is rotatable; a winding part which is movable in a direction in which the first wire is extended, so that the winding part sequentially winds a second wire around on the outer surface of the first wire being rotated; and a supply part for supplying the second wire to the winding part, wherein the supply part includes a height measuring part; a first pulley part including a movable pulley and a movable body; a bobbin part around which the second wire has been wound; a motor part for rotating the bobbin part; and a control part which controls the speed of the second wire supplied to the winding part by controlling the operation of the motor part.

A method of generating a coiled actuator fiber that includes twisting a fiber to generate a twisted fiber; wrapping the twisted fiber around a core yarn or fiber to generate a coil in the twisted fiber, which generates a coiled twisted fiber; setting the coiled twisted fiber by heat or chemical treatment; and removing at least a portion of the core yarn or fiber to generate a coiled actuator fiber.

A method of generating a coiled actuator fiber that includes twisting a fiber to generate a twisted fiber; wrapping the twisted fiber around a core yarn or fiber to generate a coil in the twisted fiber, which generates a coiled twisted fiber; setting the coiled twisted fiber by heat or chemical treatment; and removing at least a portion of the core yarn or fiber to generate a coiled actuator fiber.

An example method includes combining an interlayer and a carbon fiber fabric, wherein the interlayer comprises a highly oriented milled carbon fiber ply comprising a plurality of out-of-plane carbon fibers. The method further includes winding the interlayer and the carbon fiber fabric around a core to form a composite fiber preform comprising a plurality of layers defining an annulus extending along a central axis. The method further includes densifying the composite fiber preform.

An example method includes combining an interlayer and a carbon fiber fabric, wherein the interlayer comprises a highly oriented milled carbon fiber ply comprising a plurality of out-of-plane carbon fibers. The method further includes winding the interlayer and the carbon fiber fabric around a core to form a composite fiber preform comprising a plurality of layers defining an annulus extending along a central axis. The method further includes densifying the composite fiber preform.

An example method includes forming an interlayer on a carbon fiber fabric to form a composite fiber fabric. The interlayer comprises a binder. The method further includes winding the composite fiber fabric around a core to form a composite fiber preform comprising a plurality of layers defining an annulus extending along a central axis. The method further includes densifying the composite fiber preform.

An example method includes forming an interlayer on a carbon fiber fabric to form a composite fiber fabric. The interlayer comprises a binder. The method further includes winding the composite fiber fabric around a core to form a composite fiber preform comprising a plurality of layers defining an annulus extending along a central axis. The method further includes densifying the composite fiber preform.

A filamentary core for an elastic composite yarn, particularly for an elastic textile composite yarn, comprising at least two elastic performance filaments, wherein each of the at least two elastic performance filaments is capable of being stretched at least about 2 times its package length and has at least 90% up to 100% elastic recovery after having being released from a stretching 2 times its package length.

A filamentary core for an elastic composite yarn, particularly for an elastic textile composite yarn, comprising at least two elastic performance filaments, wherein each of the at least two elastic performance filaments is capable of being stretched at least about 2 times its package length and has at least 90% up to 100% elastic recovery after having being released from a stretching 2 times its package length.