Additive manufacturing method

An additive manufacturing method of depositing weld beads formed by melting and solidifying a filler metal while moving a welding torch attached to a robot tip shaft, the additive manufacturing method comprising:

• a step of measuring a shape profile of an existing weld bead by a non-contact shape sensor provided on the robot tip shaft integrally with the welding torch, during manufacture of an additively-manufactured object by forming the weld beads, based on a stored deposition track plan based on predetermined shape data of the additively-manufactured object and comprising a program for manufacturing the additively-manufactured object, the deposition track plan defining a target position of the welding torch and a shape of the weld beads;
• a step of extracting first geometric information of a bead shape from the shape profile and the target position of the welding torch;
• a step of extracting second geometric information corresponding to the first geometric information from the deposition track plan and calculating a deviation amount between the first geometric information and the second geometric information;
• a step of updating the deposition track plan by changing at least one of a bead height and a bead width in a cross section perpendicular to a bead longitudinal direction of the weld bead defined by the deposition track plan, according to the deviation amount;
• and
• a step of changing a welding condition according to an update result of the deposition track plan, wherein
• the first geometric information and the second geometric information include information on at least a geometric feature point near the target position of the welding torch, and
• the geometric feature point includes
• an apex of a convex shape of the existing weld bead,
• an end point of a narrowed portion formed by recessing a bead outer surface inward between the weld bead and another weld bead adjacent to the weld bead, and
• a point where an end portion of the weld bead in a width direction and a lower layer surface on which the weld bead is formed intersect.