Method for manufacturing a metal molded article and manufacturing apparatus for a metal molded article

Abstract

To provide a method for producing a metal molding and a device for producing a metal molding that can prevent large asperities from being formed on the surface of a metal molding.SOLUTION: A method for producing a metal molding is to form a metal molding on a base material. The method includes: a base material installation step S1 for installing a base material in contact with a temperature control part; and a metal deposition step S2 for depositing molten metal materials on the base material to mold a metal molding. In the metal deposition step, first, heating operation is performed to heat the base material by the temperature control part, putting the base material into a preheated state, and then the metal molding is molded on the base material.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a metal molded object and an apparatus for manufacturing a metal molded object.

Background Art

[0002] Conventionally, as a device configuration of WAAM (Wire arc additive manufacturing), a device that performs metal lamination using an arc welding robot is known.

[0003] During shaping by WAAM, since heat accumulation in the shaped object progresses due to the heat input of arc welding, there is a problem that as the shaping progresses, the bead width increases, making it difficult to perform shaping with a uniform width. In order to solve this problem, it is known to cool the shaped object using a cooling device during the process of laminating and shaping the shaped object (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, as a result of the inventor's study, it has been found that the method described in Patent Document 1 has a problem that particularly in the early stage of starting the shaping, large irregularities are formed on the surface of the shaped object as traces of the laminated metal.

[0006] Therefore, the present invention has been made in view of the above circumstances, and provides a method for manufacturing a metal molded object and an apparatus for manufacturing a metal molded object that can suppress the formation of large irregularities on the surface of the metal molded object as traces of the laminated metal.

Means for Solving the Problems

[0007] To achieve the above object, the present invention employs the following means. That is, a method for manufacturing a metal molded article according to the present invention is a method for manufacturing a metal molded article by forming a metal molded article on a base material, including a base material installation step of installing the base material in contact with a temperature adjustment unit, and a metal lamination step of laminating a molten metal material on the base material to form the metal molded article. The metal lamination step includes heating the base material with the temperature adjustment unit and performing a preheating step of preheating, and then laminating the molten metal material on the base material, and cooling the base material by a cooling step so that the base material does not become too hot due to the heat input of the molten metal material, thereby forming the metal molded article on the base material within the width of the required dimensional accuracy. In the base material installation step, a fixing jig arranged along the outer edge of the base material forming a ring shape is installed above the base material, and the base material is sandwiched between the temperature adjustment unit and the fixing jig. 。

[0008] In a conventional method for manufacturing a metal molded article, in addition to the layer formed directly above the base material with molten metal to form the metal molded article, the layers formed with molten metal to form the metal molded article are sequentially formed on the layer (underlayer) formed on the base material, and the heat radiated to the base material causes them to solidify immediately. For this reason, the newly laminated layers are difficult to conform to the underlayer, and large irregularities are likely to be formed on the surface of the metal molded article. However, in the method for manufacturing a metal molded article according to the present invention, the base material is heated by a temperature adjustment unit. As a result, in addition to the layer formed directly above the base material with molten metal to form the metal molded article, the heat radiated to the base material from the layers formed with molten metal to form the metal molded article sequentially formed on the layer (underlayer) formed on the base material is reduced. As a result, the newly laminated layers are more likely to conform to the underlayer, so that it is possible to suppress the formation of large irregularities on the surface of the metal molded article as traces of the laminated metal. Moreover, in the manufacturing method of the metal molded product configured in this way, in the metal lamination step, after heating the base material by the temperature adjustment unit, the base material is cooled. By heating the base material in this way, it is possible to suppress the occurrence of problems such as large irregularities formed on the surface of the metal molded product and a narrow bead width that occur shortly after the start of lamination. On the other hand, in the metal lamination step, after heating the base material by the temperature adjustment unit and then cooling the base material, it is possible to suppress problems such as heat accumulation due to heat input such as arc welding and a large bead width as the metal molded product is formed and the temperature rises. Therefore, in the manufacturing method of the metal molded product of this embodiment, a constant bead width can be achieved regardless of the molding timing of the metal molded product.

[0011] Further, the manufacturing apparatus for a metal molded article according to the present invention includes a molding apparatus that stacks molten metal materials to form a metal molded article, a heating apparatus that generates heat while contacting a base material on which the metal is stacked by the molding apparatus when the metal molded article is being molded by the molding apparatus, and a temperature adjustment unit having a cooling apparatus that absorbs heat from the surroundings, and a control unit that can be set to a heating mode in which the heating apparatus is operated before the metal molded article is molded on the base material, and a cooling mode in which the cooling apparatus is operated after the heating mode is stopped. The control unit starts forming the metal molded article by stacking the molten metal material on the base material in the heating mode, and after stopping the heating mode, switches to the cooling mode to cool the base material so that the base material does not become too hot due to the heat input of the molten metal material, and forms the metal molded article on the base material within the required dimensional accuracy range. In addition, the base material is sandwiched between a fixing jig installed above the base material along the outer edge of the base material forming a ring shape and the temperature adjustment unit. 。

[0012] Furthermore, in the manufacturing apparatus for a metal molded article according to the present invention, the base material is heated by a temperature adjustment unit. As a result, in addition to the layer formed directly above the base material with the molten metal to form the metal molded article, the layers formed with the molten metal to form the metal molded article are sequentially stacked on the layer (underlayer) formed on the base material, and the amount of heat radiated to the base material decreases. As a result, the newly stacked layer is more likely to conform to the underlayer, so that it is possible to suppress the formation of large irregularities on the surface of the metal molded article as traces of the stacked metal.

Advantages of the Invention

[0015] According to the manufacturing method and manufacturing apparatus for a metal molded article of the present invention, it is possible to suppress the formation of large irregularities on the surface of the metal molded article as traces of the stacked metal.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0017] A manufacturing apparatus for a metal molded article according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a manufacturing apparatus for a metal molded article according to an embodiment of the present invention. As shown in FIG. 1, the manufacturing apparatus 1 for a metal molded article includes a positioner (support base) 10, a temperature control plate (temperature adjustment unit) 20, a fixing jig 26, and a shaping robot (shaping apparatus) 3.

[0018] The positioner 10 can support a metal molded article to be described later. The positioner 10 is installed, for example, on the floor surface. The positioner 10 has a turntable 11. The upper surface 11u of the turntable 11 is planar along a horizontal plane. The turntable 11 is rotatable about an axis with a predetermined direction (for example, the vertical direction) as the axis direction. Note that, as the support base, a non-rotating table may be employed instead of the positioner 10.

[0019] The temperature control plate (temperature adjustment unit) 20 is installed on the upper surface 11u of the turntable 11 of the positioner 10. The temperature control plate 20 may be fixed to the turntable 11 of the positioner 10 with a fixture (not shown).

[0020] FIG. 2 is a diagram showing the temperature control plate 20. In FIG. 2, the case 21 is shown by a two-dot chain line. As shown in FIG. 2, the temperature control plate 20 has a case 21, a cooling pipe (cooling apparatus) 22, and a heating unit (heating apparatus) 23.

[0021] The case 21 has a substantially rectangular parallelepiped shape. A space is formed inside the case 21. Note that a thermometer (not shown) for temperature control may be incorporated in the temperature control plate 20. Alternatively, a radiation thermometer for measuring the surface temperature of a metal molded article W to be described later may be provided separately.

[0022] The cooling pipe 22 is inserted through an insertion hole (not shown) formed in the case 21 and is arranged to meander inside the case 21. The cooling pipe 22 is tubular. By flowing (operating) cooling water inside the cooling pipe 22, the flowing cooling water absorbs the surrounding heat to cool the surroundings.

[0023] The heating part 23 is, for example, a cartridge heater. By energizing (operating) the heater, heat is generated to warm the surroundings. The heating part 23 and the cooling pipe 22 are inserted through an insertion hole (not shown) formed in the case 21 and are arranged inside the case 21.

[0024] In the temperature control plate 20, a cooling mode in which cooling water is circulated through the cooling pipe 22 and a heating mode in which the heating part 23 is heated can be selectively set by a control part (not shown).

[0025] The temperature control plate 20 is installed on the upper surface 11u of the positioner 10. In the case 21, mounting holes (not shown) penetrating in the vertical direction are formed at positions where they do not interfere with the cooling pipe 22 and the heating part 23.

[0026] As shown in FIG. 1, a base material B (to be described later) can be installed on the upper surface 21u of the case 21. In other words, the temperature control plate 20 can be in contact with the base material B. In the present embodiment, the base material B is made of a metal having a rectangular shape when viewed from directly above. Note that the shape of the base material B when viewed from directly above is not limited to a rectangle and may be a circle. In plan view, the base material B is smaller than the temperature control plate 20. Mounting holes (not shown) penetrating in the vertical direction are formed at the four corners of the base material B.

[0027] The fixing jig 26 is installed on the upper surface Bu of the base material B. In plan view, the fixing jig 26 has a rectangular annular shape. The fixing jig 26 is arranged along the outer edge of the base material B. Mounting holes (not shown) penetrating in the vertical direction are formed at the four corners of the fixing jig 26.

[0028] A fixture 28 such as a bolt is inserted through the mounting holes of the fixing jig 26 and the base material B and fastened to the mounting hole of the temperature control plate 20. The fixing jig 26 is fixed to the temperature control plate 20 together with the base material B by the fixture 28. Although a bolt is used as the fixture 28 in this embodiment, a clamp or the like may be used. When a clamp is used as the fixture 28, the fixing jig 26 can be fixed to the temperature control plate 20 together with the base material B without providing mounting holes in the fixing jig 26 and the base material B.

[0029] The shaping robot 3 has a robot arm 30 and a welding torch 31. The shaping robot 3 is a 3D printer (WAAM) using the metal melting deposition method using arc welding and has a well-known configuration.

[0030] The robot arm 30 extends from a robot body (not shown). A welding torch 31 is provided at the tip of the robot arm 30. A welding wire 32 is supplied to the welding torch 31 from a wire supply device (not shown). By performing arc discharge at the tip of the welding wire 32 to melt the welding wire 32 and laminating it on the base material B, the metal workpiece W can be manufactured. In this embodiment, the metal workpiece W is cylindrical, but the shape can be set as appropriate.

[0031] Next, a method for manufacturing a metal workpiece will be described. FIG. 3 is a flowchart showing a method for manufacturing a metal workpiece. As shown in FIG. 3, a base material installation step S1 is performed. The temperature control plate 20 is installed on the upper surface 11u of the support base 10. The base material B is installed on the upper surface 21u of the temperature control plate 20. The fixing jig 26 is installed on the upper surface Bu of the base material B. A fixture 28 such as a bolt is inserted through the mounting holes of the fixing jig 26 and the base material B and fastened to the mounting hole of the temperature control plate 20.

[0032] Next, a metal lamination step S2 is performed. Using the shaping robot 3, metal (metal material) is laminated on the upper surface Bu of the base material B to form a metal shaped object W. Before laminating and forming the metal shaped object W, the temperature control plate 20 is set to the heating mode to preheat the base material B (upper surface Bu) in advance (heating step). Thereby, it is possible to suppress the formation of large irregularities on the surface of the metal shaped object W as traces where the metal is laminated. After preheating the base material B, on the upper surface Bu of the base material B with the shaping robot 3, using the welding torch 31, the metal obtained by melting the welding wire 32 by arc discharge is laminated to form the metal shaped object W. The heating of the base material B by the temperature control plate 20 is stopped when, after the start of forming the metal shaped object W on the upper surface Bu of the base material B, the influence of the temperature of the base material B, more specifically, the influence of heat dissipation to the base material B becomes small. Then, in the metal lamination step S2, as the formation of the metal shaped object W starts, while the influence of heat dissipation to the base material B becomes small, the influence caused by the heat stored in the metal shaped object W being formed due to the heat melting the welding wire 32 becomes large. Therefore, in the metal lamination step S2, after stopping the heating mode of the temperature control plate 20, the temperature control plate 20 is switched to the cooling mode to cool the base material B (upper surface Bu) (cooling step). Thereby, it is possible to suppress the increase in the bead width as the metal shaped object W is formed, and to make the bead width constant regardless of the forming timing of the metal shaped object W.

[0033] Next, the fixture 28 is removed, and the metal shaped object W integrated with the base material B is removed from the temperature control plate 20. When forming the next metal shaped object, the temperature control plate 20 can be reused.

[0034] According to the manufacturing apparatus 1 of the metal molded object configured as described above and the manufacturing method of the metal molded object, in the metal lamination step S2, before forming the metal molded object W on the base material B, the base material B is preheated by the temperature control plate 20. As a result, in addition to the layer formed immediately above the base material B with the melted metal for forming the metal molded object W, the layer formed with the melted metal for forming the metal molded object W sequentially on the layer (underlayer) formed on the base material B has a reduced amount of heat radiated to the base material B. As a result, the newly laminated layer is more likely to conform to the underlayer, so that it is possible to suppress the formation of large irregularities on the surface of the metal molded object W as traces of the laminated metal.

[0035] Also, usually, on the upper side of the metal molded object W, heat is accumulated due to heat input such as arc welding and becomes high temperature, and the bead width becomes large. On the lower side, heat is radiated to the base material B and solidifies immediately, so the bead width becomes small. In the manufacturing method of the metal molded object of the present embodiment, in the metal lamination step S2, after heating the base material B by the temperature control plate 20, the base material B is cooled. By heating the base material B in this way, it is possible to suppress the occurrence of problems such as large irregularities formed on the surface of the metal molded object W and the bead width being formed narrowly, which occur soon after the start of lamination. On the other hand, in the metal lamination step S2, after heating the base material B by the temperature control plate 20 and then cooling the base material B, it is possible to suppress the problem that the heat is accumulated due to heat input such as arc welding and the temperature becomes high and the bead width becomes large as the metal molded object W is formed. Therefore, in the manufacturing method of the metal molded object of the present embodiment, a constant bead width can be obtained regardless of the molding timing of the metal molded object W.

[0036] Also, with the fixing jig 26 sandwiching the base material B between it and the temperature control plate 20, the fixing jig 26 is fixed to the temperature control plate 20 by the fixing tool 28. Here, since the metal molded object W is formed by partially melting the base material B with heat and joining it to the base material B, the base material B shrinks due to cooling from the state of being melted and expanded by heat, so warping (so-called welding distortion) of the base material B occurs. However, since the base material B is sandwiched between the fixing jig 26 and the temperature control plate 20, the warping of the base material B is suppressed.

[0037] In addition, a thermometer is incorporated in the temperature control plate 20, which controls the temperature of the metal workpiece W, enabling shaping with a uniform width and a width with the required dimensional accuracy.

[0038] Moreover, since lamination can always be started at the same temperature, the variation of the metal workpiece W can be reduced as compared with the case of starting at normal temperature.

[0039] In addition, since position control of the cooling device itself according to the shape of the metal workpiece W is not required, the control is easy.

[0040] Note that the assembly procedures, various shapes and combinations of each component member shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

Explanation of Reference Numerals

[0041] 1... Manufacturing apparatus for metal workpiece 3... Shaping robot 10... Positioner (support base) 26... Fixing jig 28... Fixture B... Base material S1... Base material installation process S2... Metal lamination process W... Metal workpiece

Claims

1. A method for manufacturing a metal shaped object by forming a metal shaped object on a base material, comprising: a base material installation step of installing the base material in a state of being in contact with a temperature adjustment unit; a metal lamination step of laminating a molten metal material on the base material to form the metal shaped object, wherein the metal lamination step includes heating the base material with the temperature adjustment unit and performing a preheating step, and then laminating the molten metal material on the base material, and cooling the base material by a cooling step so that the base material does not become too hot due to the heat input of the molten metal material, thereby forming the metal shaped object on the base material within the required dimensional accuracy range; In the base material installation step, a manufacturing method of a metal shaped object in which a fixing jig arranged in a ring shape along the outer edge of the base material is installed above the base material, and the base material is sandwiched between the temperature adjustment unit and the fixing jig.

2. A shaping device for laminating a molten metal material to form a metal shaped object, a temperature adjustment unit having a heating device that generates heat while contacting a base material on which the metal shaped object is being formed by the shaping device and a cooling device that absorbs ambient heat; a control unit that can be set to a heating mode in which the heating device is operated before forming the metal shaped object on the base material, and a cooling mode in which the cooling device is operated after stopping the heating mode; The control unit: starts forming the metal shaped object by laminating the molten metal material on the base material in the heating mode; after stopping the heating mode, sets to the cooling mode, cools the base material so that the base material does not become too hot due to the heat input of the molten metal material, and forms the metal shaped object on the base material within the required dimensional accuracy range; A manufacturing apparatus for a metal shaped object, wherein the base material is sandwiched between a fixing jig installed above the base material along the outer edge of the base material in a ring shape and the temperature adjustment unit.

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