Method for manufacturing three-dimensional structure

A method for manufacturing a three-dimensional structure, the method comprising melting a filament that contains a thermoplastic resin by using a 3D printer, and depositing it onto a base, and

• comprising setting the filament in a 3D printer, drawing out a part of the filament through a nozzle of the 3D printer, bonding the filament at one end of the filament to a surface of the base so as to achieve a bond strength to the base of 20 to 50 N, after one end of the filament is bonded to the surface of the base, driving the 3D printer to discharge the filament, at a discharge temperature of 15 to 60° C. higher than the melting point of the thermoplastic resin, through the nozzle of the 3D printer onto a surface of the base so as to deposit thereon, while moving at least one of the base or the nozzle,
• where, the bond strength is measured by cutting the base into a 40 mm-long×60 mm-wide rectangular piece;
• bonding a 60 mm-long filament to the cut base over a 20 mm-range in parallel with the lateral side of the cut base, so that the filament originates from a point on the cut base laterally 40 mm-away and longitudinally 20 mm-away from one apex of the cut base;
• bringing a point on the cut base laterally 20 mm-away and longitudinally 20 mm-away from the apex of the cut base, and a point on the filament longitudinally 40 mm-away from the originating point thereof, apart from each other in the direction parallel to the cut base plane at a tensile speed of 5 mm/second;
• then finding the force necessary for detaching the filament,
• wherein the filament comprises a commingled yarn that contains a continuous reinforcing fiber and a continuous thermoplastic resin fiber,
• the continuous reinforcing fiber being dispersed in the continuous thermoplastic resin fiber such that at least a portion of the continuous thermoplastic resin fiber remains in the fiber form, and is not impregnated into the continuous reinforcing fiber,
• the continuous thermoplastic resin fiber has a number-average fiber length of 1 m or longer, and the continuous reinforcing fiber has a number-average fiber length of 1 m or longer, and
• the ratio of the continuous reinforcing fiber in the commingled yarn is 40% by weight or more, and the ratio of the continuous thermoplastic resin fiber in the commingled yarn is 35% by weight or more,
• a total number of fibers used for manufacturing a single commingled yarn, which is a sum of a total number of fibers of continuous thermoplastic resin fiber and a total number of fibers of continuous reinforcing fiber, is 1,000 to 100,000 f;
• and
• the continuous reinforcing fiber in the commingled yarn fiber has a dispersity of 60 to 100%.