Method and apparatus for manufacturing layered model

1. A method for producing an additively manufactured object, comprising melting and solidifying a filler metal to successively form weld beads one weld bead at a time, and depositing the weld beads adjoining each other, thereby forming a weld-bead layer, and repeatedly depositing a next weld-bead layer one weld bead at a time successively on the formed weld-bead layer to conduct additive manufacturing,

the method comprising a bead formation step of forming a new weld bead so as to fill a recess formed by at least three previously-formed weld beads of the weld-bead layer and the next weld-bead layer, in a cross-section perpendicular to a longitudinal direction of the weld beads;

the method further comprising:

inputting predetermined profile data on the additively manufactured object prior to forming any of the weld beads;

prior to forming any of the weld beads, producing a deposition model for the weld beads including a deposition procedure for producing the additively manufactured object based on the profile data;

extracting the recess from the deposition model prior to forming any of the weld beads; and

estimating a bead size of a weld bead to be formed in the recess such that the recess is filled up with the weld bead and remaking the deposition model, prior to forming any of the weld beads, such that the weld bead has the estimated bead size,

wherein in the bead formation step, the new weld bead is formed based on the remade deposition model.

2. The method for producing an additively manufactured object according to claim 1 , wherein in the bead formation step, a bead size of the new weld bead is changed such that the recess is filled up.

3. The method for producing an additively manufactured object according to claim 1 , wherein in the bead formation step, any of boundaries between the at least three previously formed weld beads is used as a target position for forming the new weld bead.

4. The method for producing an additively manufactured object according to claim 2 , wherein in the bead formation step, any of boundaries between the at least three previously formed weld beads is used as a target position for forming the new weld bead.

5. The method for producing an additively manufactured object according to claim 3 , wherein in the bead formation step, a torch axis direction of a torch to support the filler metal and melt an end of the filler metal is set to coincide with a bisector of an angle between a tangent to one of a pair of the previously formed weld beads and a tangent to another of the pair of the previously formed weld beads, the pair of the previously formed weld beads adjoining each other at the boundary which is the target position.

6. The method for producing an additively manufactured object according to claim 4 , wherein in the bead formation step, a torch axis direction of a torch to support the filler metal and melt an end of the filler metal is set to coincide with a bisector of an angle between a tangent to one of a pair of the previously formed weld beads and a tangent to another of the pair of the previously formed weld beads, the pair of the previously formed weld beads adjoining each other at the boundary which is the target position.

7. The method for producing an additively manufactured object according to claim 1 , the method comprising:

detecting a profile of portions around the recess by a profile detection sensor; and

estimating a bead size of the new weld bead to fill up the recess by use of the detected profile detection data on the recess,

wherein in the bead formation step, the new weld bead having the estimated bead size is formed in the recess.