JP2018086664A - Welding device, welding method, three-dimensional molding apparatus, and three-dimensional molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce defects in metal processing and molding with use of a molten metal.SOLUTION: The three-dimensional molding apparatus comprises: a melting head part for melting metal; a drive part for driving the melting head part; and a control part which generates a molding path on the basis of three-dimensional design data and controls the drive part. In the molding path, a first path which extends in a first direction and a second path which extends in a second direction different from the first direction are repeated. The molding path comprises a folding path, which extends in a direction separating from the second path and is folded in a direction toward the second path, between the first path and the second path.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a welding apparatus, a welding method, a three-dimensional modeling apparatus, and a three-dimensional modeling method.

  2. Description of the Related Art Conventionally, a method is known in which a metal material is build-up welded or multilayer welded using a welding apparatus to process or repair a metal structure material.

  Moreover, in a three-dimensional modeling apparatus, a metal model according to the three-dimensional design data is manufactured by using a metal as a material, melting the metal by arc discharge or the like, and then solidifying and performing so-called overlay welding. A three-dimensional modeling apparatus has also been proposed. A three-dimensional modeling apparatus that handles such a metal material is considered to be an aspect of a welding apparatus.

  However, in such a welding apparatus and three-dimensional modeling apparatus, when a metal is melted / deposited along a continuous modeling path and a structural material is to be processed and modeled, there is a defect in the modeled object (the design data includes There is a problem that voids that do not exist may be formed.

JP 2005-054197 A

  An object of the present invention is to reduce defects in metal processing and modeling using a molten metal.

A welding apparatus according to the present invention includes a melting head that melts a metal, a driving unit that drives the melting head, and a control unit that generates a welding path and controls the driving unit. The welding pass repeats a first pass extending along a first direction and a second pass extending in a second direction different from the first direction. The welding pass includes a turn-back pass extending in a direction away from the second pass and turning back in the direction toward the second pass between the first pass and the second pass. The welding method according to the present invention includes a step of generating a welding path, and a step of driving the melting head along the welding path to deposit molten metal along the welding path. The welding pass repeats a first pass extending along the first direction and a second pass extending in a second direction different from the first direction. Further, the welding pass includes a turn-back pass that protrudes and turns back in a direction away from the second pass between the first pass and the second pass.
The three-dimensional modeling apparatus according to the present invention includes a melting head for melting a metal, a driving unit that drives the melting head, and a control unit that generates a modeling path based on three-dimensional design data and controls the driving unit. With. The modeling pass repeats a first path extending along a first direction and a second path extending in a second direction different from the first direction. The modeling pass includes a folding path extending in a direction away from the second path and turning back in the direction toward the second path between the first path and the second path. The three-dimensional modeling method according to the present invention includes a step of generating a modeling path based on the three-dimensional design data, and a step of driving the melting head along the modeling path to deposit molten metal along the modeling path. Prepare. A modeling pass repeats the 1st pass extended along the 1st direction, and the 2nd pass extended in the 2nd direction different from the 1st direction. Further, the modeling pass includes a turn-back path that protrudes in a direction away from the second pass and turns back between the first pass and the second pass.

It is the schematic explaining the whole structure of the three-dimensional modeling apparatus of 1st Embodiment. It is the schematic explaining the welding torch part of 1st Embodiment. It is a conceptual diagram explaining the production | generation method of slice data and the production | generation of a modeling path | pass. It is a flowchart which shows the procedure of the three-dimensional modeling method according to the three-dimensional modeling apparatus of 1st Embodiment. It is a conceptual diagram explaining the production | generation method of the slice data Li, and the production | generation method of the modeling path FP. It is a conceptual diagram explaining the deposition of the molten metal along the modeling path FP. It is a conceptual diagram explaining the deposition of the molten metal along the modeling path FP. It is a conceptual diagram explaining the problem (development of a defect) at the time of depositing the molten metal along the modeling path FP. It is a conceptual diagram explaining the problem (development of a defect) at the time of depositing the molten metal along the modeling path FP. It is a conceptual diagram explaining the problem (development of a defect) at the time of depositing the molten metal along the modeling path FP. It is a conceptual diagram explaining the modeling path FP (folding path FPt) of the first embodiment. It is a conceptual diagram explaining the modeling path FP (folding path FPt) of the first embodiment. The effect of providing the return path FPt will be described. It is a conceptual diagram explaining the modeling path FP produced | generated by 2nd Embodiment. The schematic structure of the welding apparatus which concerns on a modification is shown. 14 shows a configuration of a melting head of the apparatus of FIG.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
With reference to FIG. 1, the whole structure of the three-dimensional modeling apparatus of 1st Embodiment is demonstrated. In the following embodiments, the “three-dimensional modeling apparatus” is not only an apparatus for newly forming a modeled object on a base material, but also deposits a metal on an existing modeled object (by overlay welding). ), Used to include an apparatus for processing or repairing an existing model.
The three-dimensional modeling apparatus shown in FIG. 1 uses an arc welding method, and a metal (for example, cast iron, mild steel, stainless steel, mold material (SKD), inconel, copper, copper alloy, nickel, nickel alloy, aluminum, titanium, magnesium alloy). Etc.) is melted and solidified (build-up welding or multilayer welding) to form a shaped article. As an example, the three-dimensional modeling apparatus includes a tank 10, a welding torch unit 30 (melting head), a cooling mechanism 40, a control device (computer) 50, and a driving unit 60.

  The tank 10 is a container that stores a modeled object to be modeled and a base material 20 on which the modeled object is deposited, and is configured to be able to hold cooling water supplied from the cooling mechanism 40. The shaped object is cooled and solidified by the cooling water supplied from the cooling mechanism 40. The water level of the cooling water in the tank 10 changes as the modeling of the model proceeds. The adjustment and discharge of the cooling water level can be performed according to a control signal from the controller 50.

  Further, the welding torch part 30 has a role of melting a metal material by arc discharge and depositing it on the base material 20. The detailed configuration of the welding torch part 30 will be described later with reference to FIG. The control device 50 performs various controls on the welding torch unit 30 and transmits a drive control signal to the driving unit 60 to drive the driving unit 60 to control the position of the welding torch unit 30 in the XYZ directions. Although detailed illustration of the drive unit 60 is omitted, as an example, a combination of an XY table and a vertical drive mechanism mounted on the XY table can be used.

  The control device 50 generates slice data based on the three-dimensional CAD data related to the shape of the modeled object supplied from the outside, and further moves the welding torch unit 30 in the XY direction based on the slice data (modeling model). Pass (welding pass)). The welding torch unit 30 moves along this modeling pass, and metal deposition based on the slice data is repeated, so that a modeled object according to the three-dimensional CAD data is formed.

  Next, a more detailed configuration example of the welding torch part 30 will be described with reference to FIG. As an example, the welding torch unit 30 includes a nozzle 31, a contact tip 32, a wire driving unit 33, a power supply 34, a shield gas supply unit 35, and a switching circuit 37.

  The nozzle 31 is a cylindrical body provided with a hollow portion penetrating the nozzle 31 in the Z direction. Through this hollow portion, the wire 36 that is the material of the modeled object is supplied, and the shield gas Gu from the shield gas supply unit 35 is supplied.

  The contact tip 32 is provided in the cavity of the nozzle 31 and is electrically connected to the wire 36 and connected to the positive terminal (+) of the power source 34 in order to apply a high voltage for generating an arc to the wire 36. ing. For example, as shown in FIG. 2, the wire driving unit 33 includes a pair of rollers arranged so as to sandwich the wire 36 from both sides. The wire drive unit 36 has a role of feeding the wire 36 into the nozzle 31 as the roller rotates.

  The power source 34 is a voltage source that generates a high voltage for arc generation, and has a positive terminal connected to the contact chip 32 and a negative terminal (−) connected to the base material 20. The electrical connection between the power supply 34 and the base material 20 or the contact chip 20 is controlled by a switching circuit 37.

The shield gas supply unit 35 is a part for supplying a shield gas for shielding the arc and arc around the weld pool from the atmosphere, and although not shown, a cylinder or a valve for storing the shield gas, etc. It has. The shield gas supply unit 35 can be controlled in accordance with a control signal from the control unit 50. The shield gas is, for example, an inert gas such as carbon dioxide (CO ₂ ) or argon (Ar), or a mixed gas thereof.

  Next, generation of slice data and generation of a modeling path will be described with reference to FIGS. 3A, 3B, and 4. FIG. 3A is a conceptual diagram illustrating a procedure for generating slice data and a modeling path, and FIG. 3B is a flowchart illustrating a procedure for a three-dimensional modeling method performed by the apparatus according to the first embodiment. FIG. 4 is a plan view showing details of the modeling pass. Here, as an example, the modeled object to be modeled and the three-dimensional CAD data CD corresponding to the modeled object will be described as having a cylindrical shape having a cavity at the center.

  As shown in FIG. 3A, the three-dimensional CAD data CD indicating the structure of a model to be modeled is divided into a plurality of layers of slice data L1, L2, L3, L4... In the control device 50 or an external device. (Step S1 in FIG. 3B). The slice data Li (i = 1, 2, 3, 4,...) Is XY plane shape data formed by cutting three-dimensional CAD data into a plane along the XY plane of three-dimensional orthogonal coordinates. Further, in each slice data Li, a modeling path FP for depositing a metal material based on the slice data Li is generated in the control device 50 (step S2 in FIG. 3B). The aforementioned welding torch part 30 moves along the modeling path FP, and the molten metal is deposited on the base material 20 or the deposited metal, so that modeling according to the slice data Li is performed (in FIG. 3B). Step S3).

  As shown in FIG. 3A and FIG. 4 which is an enlarged view, the modeling path FP has a so-called ninety-nine fold shape that folds over a plurality of times in each of the slice data L1, L2, L3, L4. Given. Specifically, as an example, the modeling pass FP is formed by repeatedly forming a first path FP1 extending in one direction (for example, the X direction) as a longitudinal direction and a second path FP2 extending in a direction different from the first direction. Can be. The first path FP1 is repeatedly formed at a predetermined arrangement pitch W1 in a direction intersecting the longitudinal direction (for example, the Y direction). The second path FP2 extends in a direction different from the first path FP1 (direction intersecting), and is formed so as to connect the two first paths FP1 arranged at such an arrangement pitch W1. Such a ninety-nine-fold shaped modeling path FP can shorten the modeling time as compared with the case where a plurality of modeling paths parallel to each other are repeatedly formed.

  In FIG. 4, all the first paths FP1 are formed with the X direction as the longitudinal direction, but the present invention is not limited to this, and some of the first paths FP1 have a direction different from the X direction. It may be formed as a longitudinal direction. In FIG. 4, the first path FP1 is all linear, but is not limited to this. Further, the arrangement pitch W1 does not have to be the same in all the first paths FP1, and can be changed according to various conditions. Further, the modeling path FP may be divided into a plurality of pieces in one slice data Li, or may be a single continuous line as in a so-called one-stroke drawing.

  The second path FP2 connects two adjacent first paths FP1, and the second path FP2 extends in a direction different from the first direction. Since the second path FP2 is a route that connects the first paths FP1, the length thereof is shorter than the first path FP1, and is about the same as the above-described pitch W1 or slightly longer than that. is there. Although not shown in FIG. 4, it is preferable that a return path FPt as described later is formed between the first path FP1 and the second path FP2.

  In addition to the 99-fold shaped modeling path FP as described above, a modeling path along the contour of the slice data Li can also be formed. For example, as shown in FIG. 4, modeling paths FPo and FPi along the outer periphery and inner periphery of the slice data Li can be formed. In this case, it is preferable that the second path FP2 is formed in a direction along the modeling path FPo or FPi. In other words, the second path FP is preferably generated so as to have a longitudinal direction in a direction along the contour of the adjacent slice data Li. In addition, the modeling path FP2 is described as having a substantially linear shape in FIGS. 3A and 4, but may be given a predetermined curvature.

As shown in FIG. 5A, when the welding torch unit 30 moves along the modeling path FP (first path FP1, second path FP2) and the molten metal moves (deposits) in the molten pool, the molten metal 37m is shaped. It has a predetermined width Wm, for example, about 5 to 10 mm, in a direction orthogonal to the path FP. For this reason, by setting the arrangement pitch W1 of the first path FP1 to, for example, the same value as the width Wm or smaller than the width Wm, it is possible to fill the metal material without any gap in each slice data Li. As shown in FIG. 5B, a method (half wrap method) in which the arrangement pitch W1 is set to about half of the width Wm is suitable, but is not limited to this.
When forming the modeling passes FPo and FPi along the contour of the slice data Li, the molten metals 37o and 37i also have a predetermined width in the direction orthogonal to the modeling passes FPo and FPi in the modeling passes FPo and FPi. The formation of the modeling paths FPo and FPi along the slice data Li is arbitrary and can be omitted.

  By the way, as shown in FIGS. 3A to 5A and 5B, when the modeling pass FP is simply repeated of the first passes FP1 and FP2, the following problems may occur depending on operating conditions and the like. is there. The problem will be described with reference to FIGS.

As described above, when the welding torch portion 30 moves along the first passes FP1 and FP2 and the molten metal moves (deposits) in the molten pool along the first pass FP1 or FP2, the molten metal is melted on both sides of the passes. The metal spreads, and the space between adjacent paths FP1 or FP2 is also filled with the deposited metal 37m. However, in the connection portion between the first path FP1 and the second path FP2, irregularities occur in the outline of the deposited metal 37m, and the molten metal is difficult to be buried in the irregularities, so that it is shown in FIG. 6 and FIG. In this way, a defect is likely to occur. That is, when filling the gap generated in the uneven part by melting the metal and spreading the molten metal on the base material or the modeled object, when the molten metal does not flow completely into the remaining gap and is not completely filled and so on. In that case, a minute defect may occur in that portion. These may also occur when the modeling passes FPi and FPo along the contour of the slice data Li are provided inside the position shown in FIG. 5B with respect to the first pass FP2, and the molten metal is laminated. The same can occur in some cases.
In the portion where the contour of the slice data L1 is close to a straight line, even if such a defect occurs, the size thereof is small (FIG. 6), but in the portion where the contour of the slice data L1 is bent (the portion where the curvature is large). In some cases, the size of the defect becomes significant (FIG. 7). Such a defect becomes a problem regardless of the presence or absence of the modeling paths FPi and FPo along the contour of the slice data Li. Moreover, the above defects can occur in the same manner when the half wrap method as shown in FIG. 5B is used.

  Therefore, in the connection portion between the first path FP1 and the second path FP2, the first path FP1 and the second path FP2 are not directly connected as shown in FIG. 8, but as shown in FIG. It is preferable to provide a return path FPt. The return path FPt is a path connecting the first paths FP1 and FP2, but the longitudinal direction is different from the first path FP1. That is, the folding path FPt has a shape that is different from the longitudinal direction of the first path FP1, protrudes in a direction away from the second path FP2, and is folded in the direction of the second path FP2. Two adjacent turn-back paths FPt face each other at their end portions. The facing distance is smaller than the arrangement pitch W1 of the first path FP1. As will be described later, with respect to the return path FPt, the welding torch unit 30 moves from the first path FP1 to the second path FP2 through the return path FPt, and conversely, the return path FPt returns from the second path FP2. The welding torch part 30 may be moved so as to go to the first path FP1 through the path FPt.

  In the illustrated example, the end of the folding path FPt has a shape that is bent at an acute angle, but the folding path FPt is not limited to this. The end portion of the return path FPt may be rounded, or a plurality of return portions may be provided. Further, the angle of the folded portion of the folded path FPt does not need to be an acute angle and may be an obtuse angle. In addition, the two modeling paths FP formed in the layers adjacent in the vertical direction may have the same position in the XY direction. Alternatively, for example, they may be set at a position shifted by half pitch. Good. The same applies to the return path FPt.

  Providing such a return path FPt between the first path FP1 and the second path FP2 can reduce the possibility of the occurrence of the defects described with reference to FIGS. That is, even in the vicinity of the connection portion between the first pass FP1 and the second pass FP2, the molten metal moves without leakage to the portion where the metal is to be deposited, and the occurrence of defects can be suppressed.

  The protrusion distance Wt of the turnback path FPt (the distance along the direction orthogonal to the corresponding first path FP1) is preferably set to 1/4 to 1/2 of the arrangement pitch W1 of the first path FP1. More preferably, it is set to 1/3.

With reference to FIG. 11, the effect of providing the return path FPt will be described. FIG. 11A is a cross-sectional photograph of a molded article when the return path FPt is not provided, and FIG. 11B is a case where the protrusion distance Wt of the return path FPt is set to 1/3 of the arrangement pitch W1. It is a cross-sectional photograph of a shaped article. In addition, the modeled object in the photograph is modeled by setting the following conditions using a welding machine manufactured by Fronius.
-Welding method: Pulse welding-Welding current: 200 [A]
-Feeding speed of the wire 36: 6.3 [mm / min]
・ Welding voltage: 16.6 [V]
・ Movement speed of welding torch part 30: 200 or 250 [mm / min]
-Heat input: 996 or 797 [KJ / m]
-Diameter of cross section of wire 36: 1.2 [mm]
Shield gas (Ar 80%, CO ₂ 20%): 20 [l / min]
-Arrangement pitch W1: 7.3 [mm]

  As is apparent from the photograph, it can be seen that the number of defects in the modeled object decreases when the folding path FPt having the protrusion distance Wt = 1 / 3W1 is provided, compared to the case where the folding path FPt is not provided.

[Second Embodiment]
Next, a three-dimensional modeling apparatus according to the second embodiment of the present invention will be described with reference to FIG. The three-dimensional modeling apparatus according to the second embodiment is different from the first embodiment in the method of forming the return path FPt. Since the basic structure (FIGS. 1 to 2) of the three-dimensional modeling apparatus and the operations other than the formation of the turn-back path FPt are the same as those in the first embodiment, a duplicate description is omitted.

  As shown in FIG. 12, in the second embodiment, the distance Lt in the longitudinal direction of the return path FPt is changed according to the curvature C of the contour of the slice data Li. For example, as shown in FIG. 12, consider a case where the curvature of the contour of the slice data Li changes from C1, C2, and C3 depending on the location. The length in the longitudinal direction of the folded path FPt in the vicinity of the contour of the curvature C1 is Lt1, the length in the longitudinal direction of the folded path FPt in the vicinity of the contour of the curvature C2 (> C1) is Lt2, and the curvature C3 (> C2). Let Lt3 be the length in the longitudinal direction of the folding path FPt in the vicinity of the contour of. In this case, the relationship between the lengths Lt1, Lt2, and Lt3 is set as Lt3> Lt2> Lt1.

  In a portion where the curvature C of the outline of the slice data Li is large, the distance between the roots of the two opposing folding paths FPt (the virtual intersection Xi of the first path FP1 and the second path FP2) is the curvature of the outline. It becomes larger than a small part. For this reason, if the length Lt in the longitudinal direction of the return path FPt is the same regardless of the curvature C of the contour of the slice data Li, there is a possibility that a defect will occur in that portion. For this reason, in 2nd Embodiment, generation | occurrence | production of a defect is suppressed by changing length Lti according to the curvature of the outline of slice data Li.

[Others]
As described above, the three-dimensional modeling apparatus using the arc welding method has been described as an example of the apparatus for processing or forming the metal material, but the present invention is not limited to this. For example, in the above-described example, a three-dimensional modeling apparatus that forms a modeling path based on three-dimensional CAD data and moves the welding torch part along the modeling path has been described. However, instead of performing modeling based on three-dimensional CAD data, for example, so-called teaching is performed, the movement path (modeling path) of the welding torch part is stored in the control unit, and the metal structure material is processed according to the stored modeling path. The present invention can also be applied to a welding apparatus that performs the above.

  The present invention can also be applied to a laser welding type welding apparatus and a metal 3D printer as shown in FIGS. 13 and 14 as an example. A laser welding type welding apparatus 100A (three-dimensional modeling apparatus) in FIG. 13 includes, as an example, a housing 10A, a melting head 30A, a control device (computer) 50A, and a drive unit 60A.

  The housing 10A is a container that stores a modeled object to be modeled and a base material 20A on which the modeled object is deposited. The melting head 30A has a role of melting metal powder with a laser and depositing it on the base material 20A. The detailed configuration of the melting head 30A will be described later with reference to FIG. The control device 50A performs various controls on the melting head 30, and transmits a drive control signal to the driving unit 60A to drive the driving unit 60A, thereby controlling the position of the melting head 30A in the XYZ directions.

  Further, the control device 50A generates slice data based on the three-dimensional CAD data relating to the shape of the modeled object supplied from the outside, and further moves the melting head 30A in the XY direction based on the slice data (modeling path). ) Is generated. The melting head 30A moves along this modeling path, and metal deposition based on the slice data is repeated, so that a modeled object according to the three-dimensional CAD data is formed. This is the same as the welding apparatus and three-dimensional modeling apparatus of the above-described embodiment (arc welding method).

  Next, a more detailed configuration example of the melting head 30A will be described with reference to FIG. For example, the melting head 30A includes a nozzle 301, a laser irradiation unit 302, a metal powder supply nozzle 303, a shield gas supply unit 305, and a drive unit 306.

  The nozzle 301 is a cylindrical body provided with a hollow portion penetrating the nozzle 301 in the Z direction. Through this hollow portion, the metal powder Pw, which is the material of the modeled object, is supplied, and the shield gas Gu from the shield gas supply unit 305 is supplied.

  The laser irradiation unit 302 includes a laser light source and a condensing optical system (not shown), and condenses the laser light LB on the surface of a modeled object (such as the base material 20). The metal powder Pw is melted by the condensed laser light. The metal powder supply nozzle 303 is disposed inside the nozzle 301 together with the laser irradiation unit 302 and supplies the metal powder Pw. The laser irradiation unit 302 and the metal powder supply nozzle 303 are controlled by the driving unit 306. The shield gas supply unit 305 supplies the inert gas Gu near the molten pool. Also in the welding apparatus or the metal 3D printer of FIGS. 13 and 14, it is possible to form the modeling path FP similar to the above embodiment. Further, the formation of the modeling path FP may be performed based on 3D CAD data as in the above-described embodiment, or may be performed by so-called teaching.

  As mentioned above, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Tank, 30 ... Welding torch part, 30A ... Melting head, 31, 301 ... Nozzle, 32 ... Contact tip, 33 ... Wire drive part, 34 ... Power supply, 35, 305 ... Shield gas supply unit, 37 ... Switching circuit, 40 ... Cooling mechanism, 50, 50A ... Control device (computer), 60, 60A ... Drive unit, CD ... 3D CAD data, Li ... slice data, FP, FPi, FPo ... modeling pass, FP1 ... first pass, FP2 ... second pass, FPt ... turnback pass.

Claims (16)

A melting head for melting the metal;
A drive unit for driving the melting head;
A control unit that generates a welding path and controls the drive unit,
The welding pass is
A first path extending along a first direction;
A second path extending in a second direction different from the first direction, and the welding path protrudes in a direction away from the second path between the first path and the second path. With a return path
A welding apparatus characterized by that. The first pass is repeatedly formed at a first interval,
The welding apparatus according to claim 1, wherein the return path has a first length along a direction orthogonal to the first path shorter than the first interval.   The welding apparatus according to claim 2, wherein the first length is 1/3 of the first interval. Generating a weld pass;
Driving a melting head along the welding path to deposit molten metal along the welding path;
The welding pass is
A first path extending along a first direction;
A second path extending in a second direction different from the first direction, and the welding path protrudes in a direction away from the second path between the first path and the second path. With a return path
A welding method characterized by the above. The first pass is repeatedly formed at a first interval,
The welding method according to claim 4, wherein the return path has a first length along a direction orthogonal to the first path shorter than the first interval.   The welding method according to claim 5, wherein the first length is 1/3 of the first interval. A melting head for melting the metal;
A drive unit for driving the melting head;
A control unit that generates a modeling pass based on the three-dimensional design data and controls the drive unit;
The modeling pass is
A first path extending along a first direction;
A second path extending in a second direction different from the first direction, and the modeling path projects in a direction away from the second path between the first path and the second path. With a return path
A three-dimensional modeling apparatus characterized by this. The first pass is repeatedly formed at a first interval,
The three-dimensional modeling apparatus according to claim 7, wherein the return path has a first length along a direction orthogonal to the first path shorter than the first interval.   The three-dimensional modeling apparatus according to claim 8, wherein the first length is 1/3 of the first interval. The modeling path is formed along slice data generated by dividing three-dimensional CAD data of a modeled object to be modeled along a plane,
The three-dimensional modeling apparatus according to claim 7, wherein the second path is generated with a direction along an outline of the slice data as a longitudinal direction.   The three-dimensional modeling apparatus according to claim 10, wherein a length of the second path in the longitudinal direction is set to be larger as a curvature of a contour of the adjacent slice data is larger. Generating a modeling path based on the three-dimensional design data;
Driving the melting head along the modeling path to deposit molten metal along the modeling path;
The modeling pass is
A first path extending along a first direction;
A second path extending in a second direction different from the first direction, and the modeling path projects in a direction away from the second path between the first path and the second path. With a return path
A three-dimensional modeling method characterized by this. The first pass is repeatedly formed at a first interval,
The three-dimensional modeling method according to claim 12, wherein the return path has a first length along a direction orthogonal to the first path shorter than the first interval.   The three-dimensional modeling method according to claim 13, wherein the first length is 1/3 of the first interval. The modeling path is formed along slice data generated by dividing three-dimensional CAD data of a modeled object to be modeled along a plane,
The three-dimensional modeling method according to claim 13, wherein the second path is generated with a direction along an outline of the slice data as a longitudinal direction.   The three-dimensional modeling method according to claim 15, wherein the length in the longitudinal direction of the second path is set to be larger as the curvature of the contour of the adjacent slice data is larger.