JP7376466B2 - Manufacturing method and device for additively manufactured products - Google Patents

Description

The present invention relates to a method and apparatus for manufacturing a laminate-molded article.

Gas-shielded arc welding is known in which a shielding gas (inert gas) is supplied to the welding area to shield the welding area from air and prevent oxidation. Gas shield welding torches used in such gas shield arc welding are described, for example, in Patent Documents 1 and 2.
The torch of Patent Document 1 has a shielding gas passage provided in the torch and a control gas passage that controls the cross-sectional shape of the weld bead as independent passages, and is symmetrical in the welding direction with respect to the welding arc. The above-mentioned passages are arranged in a vertical line at one position. According to Patent Document 1, when welding a narrow gap, the cross-sectional shape and penetration of the weld bead can be improved by providing a front shield gas flow path and a rear shield gas flow path to control the gas flow rate. It is described in.

Furthermore, in the torch of Patent Document 2, the shield gas supply section is divided into a front shield gas supply section, a center shield gas supply section, and an after shield gas supply section, and the center shield gas supply section extends to the bottom of the narrow groove. The outer dimensions are such that it can be inserted, and the area around the tungsten electrode at the center is a flow path for center shield gas. According to this, it is described in Patent Document 2 that welding can be performed while controlling the penetration depth and bead shape while preventing the occurrence of welding defects.

Japanese Patent Application Laid-open No. 64-48678 Japanese Patent Application Publication No. 9-295149

By the way, when performing gas-shielded arc welding using a base material or filler metal (welding wire) made of active metals, the active metals have a particularly strong affinity with the atmosphere at high temperatures, and react with oxygen and nitrogen in the air. This makes it easier to form oxides and nitrides. Therefore, hardening and brittleness of the oxide and nitride formed portions after welding become significant.
Therefore, when performing gas-shielded arc welding of active metals, an after-shielding jig is generally used to implement local gas shielding near the torch in order to avoid contact between the atmosphere and the active metals. .
However, when additively manufacturing a filler material such as pure titanium or titanium alloy by melting it, it is not possible to suppress the intrusion of oxygen and nitrogen into the molded object below the specified values by simply using an aftershield jig. It will still be difficult.

Therefore, even when pure titanium or a titanium alloy filler material is used, the present invention can suppress the intrusion of oxygen and nitrogen into the weld bead and prevent the mechanical properties of the laminate from deteriorating. The purpose of the present invention is to provide a manufacturing method and a manufacturing device for a laminate-molded article.

The present invention consists of the following configuration.
(1) A method for manufacturing a laminate-molded article, in which a laminate-molded article is manufactured by repeatedly laminating welded beads made by melting and solidifying pure titanium or titanium alloy filler material, the method comprising:
heating and melting the filler material at the tip of the torch while supplying the filler material to a torch to form a weld bead;
Injecting a shielding gas to shield the welding bead from the atmospheric atmosphere;
including;
The shielding step includes:
Injecting the shielding gas from an injection port provided at the tip of the torch,
Of a pair of gas shielding jigs that are provided independently on the torch and each of which has a shielding gas injection area extending in one direction from the torch, one of the gas shielding jigs is disposed in front of the direction of movement of the torch, and the other is arranged at the rear in the moving direction of the torch,
A method for manufacturing a layered product.
(2) An apparatus for producing a laminate-molded article, which repeatedly laminates welded beads made by melting and solidifying pure titanium or titanium alloy filler metal to form a laminate-molded article,
Torch and
a torch moving mechanism that moves the torch;
a filler material supply unit that supplies the filler material to the torch;
a pair of gas shield jigs each independently provided on the torch;
a shielding gas supply unit that supplies shielding gas to the torch and the pair of gas shielding jigs;
Equipped with
The pair of gas shielding jigs is formed such that an injection port for the shielding gas supplied from the shielding gas supply unit extends in one direction from the torch,
One of the pair of gas shield jigs is disposed at the front in the direction of movement of the torch, and the other is disposed at the rear in the direction of movement of the torch.
Manufacturing equipment for additively manufactured products.

According to the present invention, even when pure titanium or a titanium alloy filler material is used, oxygen and nitrogen intrusion into the weld bead is suppressed, thereby preventing the mechanical properties of the additively manufactured product from deteriorating. can.

FIG. 1 is a schematic configuration diagram of a gas shield welding apparatus. FIG. 2 is a perspective view showing a schematic configuration of a pair of gas shield jigs and a cover member attached to the torch. (A) of FIG. 3 is a schematic cross-sectional view showing the internal structure of the gas shielding jig, and (B) is a schematic cross-sectional view of the gas shielding jig shown in (A) along line III-III. . FIG. 4 is an explanatory diagram schematically showing the flow of shielding gas through the gas shielding jig and cover member during welding. FIGS. 5A and 5B are explanatory diagrams schematically showing a case where a gas shielding jig is provided only on the downstream side of the torch in the welding direction and no before shielding gas is supplied. (A) and (B) in FIG. 6 schematically illustrate the case where gas shielding jigs are provided on the upstream and downstream sides of the torch in the welding direction and before shielding gas and after shielding gas are supplied. It is a diagram. FIGS. 7A and 7B are explanatory diagrams showing, in a top view, how the gas shielding jig is rotated to avoid interference with obstacles. FIGS. 8A and 8B are explanatory side views showing how the gas shielding jig is moved up and down to avoid interference with obstacles. FIG. 9 is a graph showing the analysis results of oxygen concentration and nitrogen concentration according to the presence or absence of a before shield and the presence or absence of a cover member.

Embodiments of the present invention will be described in detail below with reference to the drawings.
The manufacturing apparatus for a laminate-produced article according to the present invention will be explained here using an example in which a laminate-produced article is manufactured by gas-shielded arc welding, but the present invention is not limited to this, and can also be applied to other welding methods such as laser welding. It is also applicable when using

<Gas shield welding equipment>
FIG. 1 is a schematic configuration diagram of a gas shield welding apparatus.
The gas shield welding apparatus 100, which is an apparatus for manufacturing a laminate-molded product, includes a welding robot 11, a robot controller 13, a filler material supply section 15, a shield gas supply section 17, a welding power source 19, a control section 21, Equipped with

The welding robot 11 is an articulated robot, and a torch 23 is supported on the tip shaft. The position and orientation of the torch 23 can be arbitrarily set three-dimensionally within the degree of freedom of the robot arm. The torch 23 holds the filler metal M continuously supplied from the filler metal supply section 15 in a state protruding from the tip of the torch. In this way, the welding robot 11 functions as a torch moving mechanism.

The torch 23 has a shield nozzle (not shown), and shield gas is supplied to the welding part from the shield nozzle. The arc welding method may be a consumable electrode type such as coated arc welding or carbon dioxide arc welding, or a non-consumable electrode type such as TIG welding or plasma arc welding, and the method may be selected as appropriate depending on the layered product to be manufactured. Ru.

For example, in the case of a consumable electrode type, a contact tip is arranged inside the shield nozzle, and the filler material M to which melting current is supplied is held in the contact tip. The torch 23 holds the filler metal M and generates an arc from the tip of the filler metal M in a shielding gas atmosphere. The filler metal M is fed to the torch 23 by a feeding mechanism (not shown) attached to a robot arm or the like. When the continuously fed filler material M is melted and solidified while moving the torch 23, a weld bead B, which is a molten solidified body of the filler material M, is formed on the base plate 25.

The heat source for melting the filler metal M is not limited to the above-mentioned arc. For example, other heat sources may be used, such as a heating method using a combination of an arc and a laser, a heating method using plasma, a heating method using an electron beam or a laser, and the like. When heating with an electron beam or laser, the amount of heating can be controlled more precisely, the state of the weld bead can be maintained more appropriately, and this can contribute to further improving the quality of the layered product.

As the filler metal M, a welding wire for welding titanium and titanium alloys is used (see, for example, JIS Z 3331).

The shielding gas supply section supplies inert gas to the welding section. In MIG welding, argon, helium (or a mixture thereof), or a gas prepared by adding a small amount of active gas such as oxygen or carbon dioxide to these gases is used as a shielding gas. On the other hand, in MAG welding, carbon dioxide gas or a mixed gas of argon and carbon dioxide gas is used as a shielding gas, and in TIG welding, argon gas is used. Furthermore, in laser welding, nitrogen, argon, helium, or the like is used as a shielding gas.

The torch 23 is provided with a pair of gas shielding jigs 27A and 27B, each of which has a shielding gas injection area extending in one direction from the torch 23, respectively, although the details will be described later. One gas shield jig 27A is disposed in front of the torch 23 in the moving direction and injects the before shield gas to the upstream side of the welding part in the welding direction WD. The other gas shielding jig 27B is arranged at the rear in the moving direction of the torch 23, and injects aftershielding gas to the downstream side of the welding part in the welding direction WD.

Further, it is preferable that the torch 23 is provided with a cover member 29 that covers the periphery of the torch 23 and the pair of gas shield jigs 27A and 27B.

The robot controller 13 receives instructions from the control unit 21, drives each part of the welding robot 11, and controls the output of the welding power source as necessary.

The control unit 21 is constituted by a computer device including a CPU, memory, storage, etc., and executes a drive program prepared in advance or a drive program created under desired conditions to drive each part of the welding robot 11 and the like. As a result, the torch 23 moves according to the drive program, and a plurality of layers of welding beads B are stacked on the base plate 25, thereby forming a multilayered layered product W.

<Gas shield jig>
FIG. 2 is a perspective view showing a schematic configuration of a pair of gas shield jigs 27A, 27B and a cover member 29 attached to the torch 23. As shown in FIG.
The pair of gas shield jigs 27A and 27B are each supported by a support portion 31 fixed to the torch 23. The support portion 31 supports the gas shielding jig 27A so as to be rotatable about the axis L of the torch 23 and also movably along the axis L. Further, it is preferable that the support part 31 supports the gas shield jig 27B so as to be freely rotatable around the axis L and movably along the axis L; Alternatively, the gas shield jig 27B may be immovably fixed to the torch 23.

The support portion 31 includes a pneumatic or electric actuator (not shown). Thereby, the support section 31 functions as a rotation mechanism that rotates the gas shield jig 27A, which is disposed in front of the torch 23 in the moving direction, around the torch 23 in response to a command from the control section 21 or the robot controller 13. It also functions as a linear motion mechanism that moves the torch 23 along the axis L. The support part 31 may have the function of rotating and linearly moving the gas shielding jig 27B similarly to the gas shielding jig 27A.

FIG. 3A is a schematic cross-sectional view showing the internal structure of the gas shielding jigs 27A and 27B, and FIG. FIG. Note that in FIG. 3, the support portion 31 is omitted.
As shown in FIG. 3A, the gas shield jigs 27A and 27B include a rectangular box-shaped housing 33 having an opening 33a, and a wire mesh 35 made of copper or stainless steel that covers the opening 33a. , a flow regulator 37 arranged inside the housing 33 and made of a laminated material of steel wool or mesh, a gas supply pipe 39 that supplies shielding gas G2 to the housing 33, and a diffusion pipe connected to the gas supply pipe 39. 41. The fluid regulator 37 is arranged on the wire mesh 35 side in the housing 33, and on the opposite side of the wire mesh 35 side of the fluid regulator 37, a diffusion pipe 41 is arranged and an internal space 43 is defined.

The gas supply pipe 39 is introduced into the housing 33 from the upper surface 33b of the housing 33, and is connected to a diffusion pipe 41 arranged inside the housing 33. A plurality of openings 41a are formed in the diffusion pipe 41, and the shielding gas G2 is dispersed and released into the internal space 43 within the housing 33 from each opening 41a. The shielding gas G2 discharged from the diffusion pipe 41 convects in the internal space 43, and then is laminarized by the rectifier 37, and then discharged from the wire mesh 35 to the outside of the casing 33. The configuration of the gas shielding jigs 27A and 27B described above is just an example, and for example, the configuration may be such that the diffusion pipe 41 is omitted, or the inside of the casing 33 is hollow. Further, although the pair of gas shield jigs 27A and 27B have the same rectangular parallelepiped shape, the shape is not limited to this.

<Cover member>
As shown in FIG. 2, the cover member 29 includes a cover support part 45 fixed to the torch 23, a skeleton member 47 that is elastically deformably held by the cover support part 45 and arranged surrounding the torch 23, and a skeleton A sheet member 49 is provided to cover the member 47 and define a torch surrounding space 51. In this configuration, the shielding gases G1 and G2 are supplied from the shielding gas supply section 17 to the torch surrounding space 51 defined inside the sheet member 49.

The cover support portion 45 may integrally support the frame member 47 and the seat member 49, and may be provided with a slide mechanism that moves the frame member 47 and the seat member 49 up and down along the axis L of the torch 23 as necessary. good. In this case, the sliding mechanism may be a screw (not shown) or a structure using an actuator such as an air cylinder.

The skeleton member 47 includes at least one rod-shaped support piece 47a, a first annular portion 47b, a second annular portion 47c, and a plurality of rod-shaped support portions 47d.
One end of the support piece 47a is fixed to the cover support part 45, and the other end is fixed to the first annular part 47b. In the configuration shown in FIG. 2, a plurality of support pieces 47a are radially connected to the cover support part 45.

The first annular portion 47b is disposed on the proximal end side of the torch 23, and the second annular portion 47c is disposed on the distal end side of the torch 23 apart from the first annular portion 47b. The first annular portion 47b and the second annular portion 47c are connected by a plurality of support portions 47d. The second annular portion 47c has a larger diameter than the first annular portion 47b, so that the frame member 47 has a shape that becomes wider as it goes from the torch base end toward the torch tip end along the axis L of the torch 23. has.

The sheet member 49 is provided to cover the skeleton member 47. The torch surrounding space 51 inside the sheet member 49 is filled with shielding gas, thereby shielding the welded portion inside the sheet member 49 from the atmosphere. Further, an opening 49a is provided in the upper part of the sheet member 49 on the base end side of the torch, and opens the torch surrounding space 51 to the atmosphere. That is, the sheet member 49 has a truncated cone shape (circumferential shape of a truncated cone) passing through the torch 23 along the axis L, and the tip edge of the frame member 47 with a widened base (the position of the second annular portion 47c) An outer edge end 49b is provided at a position further extending from. The sheet member 49 is integrated with the skeleton member 47 by bonding or locking at least a portion of the portion that contacts the skeleton member 47 with the skeleton member 47 .

The skeleton member 47 only needs to have enough strength to maintain the shape of the sheet member 49, and is made of easily deformable metal wire such as steel wire, piano wire, hard steel wire, stainless steel wire, or resin wire. be done. Furthermore, it is not limited to wire rods, and may be constructed using band materials, plate materials, etc. alone or in combination.

Since the sheet member 49 is arranged near the torch 23, it is preferably a fireproof sheet or a flameproof sheet. Further, it is preferable that the entire or at least a portion of the sheet member 49 is made of a material that is translucent, since the welded portion inside the sheet member 49 can be visually checked and the welding state can be easily monitored.

Examples of flame retardant sheets or noncombustible sheets include sheets with flame retardant properties specified in JIS A 8952 "Sheets for construction work" and JIS A 1323-1995 "Flame retardant properties against welding and fusing sparks for sheets for construction work". Examples include sheets of type A, type B, and type C specified in ``Test Methods''. Examples of the translucent sheet include, for example, a transparent noncombustible sheet in which a base fabric of glass fiber cloth is coated with a photocurable resin.

The cover member 29 of this configuration covers the torch 23 and the pair of gas shielding jigs 27A, 27B, and protects the shielding gas G1 supplied to the torch 23 and the shielding gas G2 supplied to the gas shielding jigs 27A, 27B. is retained in the space inside the cover.

<Effects of gas shield jig>
Next, the state of gas shielding by the gas shielding jigs 27A and 27B will be explained.
FIG. 4 is an explanatory diagram schematically showing the flow of shielding gas by the gas shielding jigs 27A, 27B and the cover member 29 during welding.

When forming a weld bead B on the base plate 25 by generating an arc from the torch 23, the shield gas G1 is supplied from the torch 23 to the welding part, and the before shield gas and the gas shield jig are supplied from the gas shield jig 27A. After shield gas is supplied from 27B. The before shielding gas and the after shielding gas may be the same type of shielding gas or may be different types. Further, the gas supply speed (pressure) may be the same or different on both sides.

Here, the difference in the state of the welded part depending on the presence or absence of before shielding gas will be explained.
FIGS. 5A and 5B are explanatory diagrams schematically showing a case where a gas shielding jig 27B is provided only on the downstream side of the torch 23 in the welding direction WD and no before shielding gas is supplied. . (A) and (B) of FIG. 6 show the situation when gas shielding jigs 27A and 27B are provided on the upstream and downstream sides of the torch 23 in the welding direction WD, and before shielding gas and after shielding gas are supplied. It is an explanatory view shown typically.

As shown in FIG. 5A, adsorbed oxygen and adsorbed nitrogen 55 exist on the surface of the base plate 25. As shown in FIG. 5B, as the torch 23 is moved in the welding direction WD, adsorbed oxygen and adsorbed nitrogen 55 are taken into the weld metal at the welding part directly below the torch 23, and oxygen is added to the weld bead. becomes easier to invade.

On the other hand, as shown in FIG. 6A, when a gas shield jig 27A is provided on the upstream side of the torch 23 in the welding direction WD and before shield gas is supplied, the adsorbed oxygen and adsorbed nitrogen 55 on the surface of the base plate 25 are Blows away by before shield gas. As a result, as shown in FIG. 6(B), adsorbed oxygen and adsorbed nitrogen 55 are reduced in the welded portion directly under the torch 23. It is thought that by supplying the before shield gas in this manner, an effect of suppressing the intrusion of oxygen and nitrogen into the weld bead can be obtained.

Further, as shown in FIG. 4, when the shielding gas G1 from the torch 23 and the shielding gas G2 from the gas shielding jigs 27A and 27B are supplied into the cover member 29, the supplied shielding gases G1 and G2 are , convection occurs within the torch surrounding space 51 surrounded by the sheet member 49. Then, since the shielding gases G1 and G2 such as argon and carbon dioxide gas have a higher specific gravity than air, they accumulate below the torch surrounding space 51 (an area from the surface of the base plate 25 to the height H1). Further, fumes during welding and surplus shielding gases G1 and G2 are discharged from the torch surrounding space 51 through an opening 49a provided on the torch base end side of the sheet member 49 (upper part in FIG. 4).

The widened outer edge 49b of the sheet member 49 is disposed in contact with the base plate 25 or extends close to the surface of the base plate 25, so that the total gap area of the height H2 between the outer edge 49b and the base plate 25 is is smaller than the opening area of the opening 49a. Therefore, leakage of the shielding gases G1 and G2 from the outer edge 49b of the sheet member 49 is suppressed, and they continue to stagnate below the torch surrounding space 51. As a result, the welded portion and the welded end portion are always covered with the shielding gases G1 and G2, and the insulation from the atmosphere is improved.

In this way, the shielding gases G1 and G2 supplied to the torch surrounding space 51 once stagnate in the lower part of the torch surrounding space 51 (region of height H1), and then are mainly discharged from the upper opening 49a.
Furthermore, as the height H2 of the outer edge 49b of the sheet member 49 becomes higher, the proportion of the shielding gases G1 and G2 supplied to the torch surrounding space 51 being discharged from the gap at the height H2 increases. residence time becomes shorter. Therefore, by adjusting the gap of the height H2 of the cover member 29, welding environmental conditions such as the concentration, pressure, and replacement frequency of the shielding gases G1 and G2 in the torch surrounding space 51 can be changed. According to this, it is possible to optimize welding conditions according to the object to be welded, and it is possible to improve welding quality.

Furthermore, if the gas shield jig 27A shown in FIG. 4 is placed on the upstream side in the welding direction WD, it may interfere with obstacles depending on the welding location. Therefore, the gas shield jig 27A having this configuration supports the torch 23 so as to be rotatable as described above.

FIGS. 7A and 7B are explanatory diagrams showing, in a top view, how the gas shield jig 27A is rotated to avoid interference with obstacles.
As shown in FIG. 7A, when there is a wall 57 that becomes an obstacle on the upstream side of the welding direction WD, the torch 23 is moved while the gas shield jigs 27A and 27B are arranged in a straight line. Then, the gas shield jig 27A hits the wall portion 57. In that case, the torch 23 cannot be moved close to the wall portion 57. Therefore, as shown in FIG. 7B, the gas shield jig 27A is rotated in the direction of arrow R around the torch 23 to avoid interference between the gas shield jig 27A and the wall portion 57. Thereby, the torch 23 can be placed closer to the wall portion 57, and the weldable range can be expanded.

The movement of the gas shield jig 27A to avoid obstacles is not limited to a rotational movement, but may be a sliding movement to change the height from the welding position.
FIGS. 8A and 8B are explanatory diagrams showing, in side view, how the gas shield jig 27A is moved up and down to avoid interference with obstacles.

As shown in FIG. 8(A), when there is an existing weld bead B that becomes an obstacle on the upstream side of the welding direction WD, gas shield jigs 27A and 27B are arranged linearly at the same height. If the torch 23 is moved in this state, the gas shield jig 27A will hit the weld bead B. In that case, the torch 23 cannot be moved close to the welding bead B. Therefore, as shown in FIG. 8B, the gas shield jig 27A is slid in the direction of arrow S along the axis L of the torch 23 to avoid interference between the gas shield jig 27A and the weld bead B. . Thereby, the torch 23 can be placed closer to the welding bead B, and the weldable range can be expanded. In this case, a new weld bead can be formed on the weld bead B by further raising the torch 23.

Conditions such as the rotation direction and rotation angle of the gas shielding jig 27A, and conditions such as the sliding direction and sliding amount are appropriately set according to the shape of obstacles such as the wall portion 57 and the weld bead B. Instructions for rotating and sliding the gas shield jig 27A may be included in a predetermined drive program, and an image sensor, a magnetic sensor, and various contact-type position sensors that move together with the torch 23 may be provided. , obstacles are detected in real time, and if an obstacle is detected during weld bead formation, the gas shield jig 27A is rotated, slid, or rotated and slid to avoid interference with the obstacle. It may be configured to do so.

Although only the gas shielding jig 27A is rotated and slid in the above description, the gas shielding jig 27B may also be allowed to rotate and slide in the same manner. In either case, the posture limit and the movable range limit of the robot holding the torch 23 can be expanded, and various welding situations can be flexibly handled.

Note that the cover member 29 has a structure that can be flexibly deformed, and the skeleton member 47 has an elastic restoring force that allows the shape bent by an external force to return to the original shape due to its own elasticity when the external force is released. . Therefore, the cover member 29 does not hinder the movement of the torch 23.

The oxygen concentration and nitrogen concentration of the weld bead when the before-shielding and after-shielding using the gas shielding jigs 27A and 27B described above are not performed and when they are performed, and when the gas shielding jigs 27B are used and when they are not performed are respectively shown below. I asked for it.

The welding conditions that formed the weld bead were as follows.
Welding current: 160A
Welding voltage: 15V
(DC pulse drive)
Welding speed: 20cm/min
(Welding heat input: approx. 720J/mm)
Torch gas flow rate: 25L/min, Ar (100%)
Before shield gas flow rate: 25L/min, Ar (100%)
Aftershield gas flow rate: 25L/min, Ar (100%)
Filler material: Pure titanium solid wire WT2G (made by Daido Steel)
Build shape: 3 passes x 3 layers laminate

Oxygen concentration and nitrogen concentration were measured for each weld bead of the above-mentioned 3×3 weld bead laminate by an inert gas dissolution method (oxygen measurement method: JIS H 1620, nitrogen measurement method: JIS H 1612). .

When performing after-shielding, we confirmed the difference in the distribution of oxygen and nitrogen concentrations depending on the presence or absence of a before-shield and the presence or absence of a cover member, and found that when shielding gas is retained using a cover member, it is not retained. Compared to the case, a decrease in oxygen and nitrogen concentrations was observed. However, the distribution of oxygen and nitrogen concentrations varied, and sometimes fell outside the JIS H4600 2 standards of oxygen concentration of 2000 ppm or less and nitrogen concentration of 300 ppm or less. Specifically, the nitrogen concentration sometimes exceeded the limit value of 0.03% by mass (value corresponding to 300 ppm according to the above-mentioned JIS standard).

FIG. 9 is a graph showing the analysis results of oxygen concentration and nitrogen concentration according to the presence or absence of a before shield and the presence or absence of a cover member.

When the before shield was not performed and the cover member was not provided (Test Example 1), the oxygen content was 0.16% by mass and the nitrogen content was 0.046% by mass.
In addition, when the cover member was provided without implementing the before shield (Test Example 2), the oxygen content was 0.14% by mass and the nitrogen content was 0.043% by mass, which was more than in Test Example 1. The content decreased.

On the other hand, when performing a before shield and not providing a cover member (Test Example 3), the oxygen content was 0.143% by mass and the nitrogen content was about 0.03% by mass, which was higher than Test Examples 1 and 2. Nitrogen content was further reduced.
Furthermore, when a before shield is performed and a cover member is provided (Test Example 4), the oxygen content is 0.133% by mass and the nitrogen content is approximately 0.03% by mass, which is lower than in Test Example 3. The amount decreased further.

From the above, when both the before shield and after shield were performed and the cover member was provided, both the oxygen content and the nitrogen content became the minimum values, and a high quality weld bead was formed.

The present invention is not limited to the embodiments described above, and those skilled in the art may combine the configurations of the embodiments with each other, or make changes and applications based on the description of the specification and well-known techniques. This is the intended purpose of the invention and falls within the scope for which protection is sought.

As mentioned above, the following matters are disclosed in this specification.
(1) A method for manufacturing a laminate-molded article, in which a laminate-molded article is manufactured by repeatedly laminating welded beads made by melting and solidifying pure titanium or titanium alloy filler material, the method comprising:
heating and melting the filler material at the tip of the torch while supplying the filler material to a torch to form a weld bead;
Injecting a shielding gas to shield the welding bead from the atmospheric atmosphere;
including;
The shielding step includes:
Injecting the shielding gas from an injection port provided at the tip of the torch,
Of a pair of gas shielding jigs that are provided independently on the torch and each of which has a shielding gas injection area extending in one direction from the torch, one of the gas shielding jigs is disposed in front of the direction of movement of the torch, and the other is arranged at the rear in the moving direction of the torch,
A method for manufacturing a layered product.
According to this method for producing a laminate-manufactured article, the welding part can be before-shielded by the gas shielding jig placed at the front in the direction of torch movement, and the welding part can be after-shielded by the gas shielding jig placed at the rear in the direction of torch movement. can be done. Since both gas shield jigs are independently provided on the torch, one and the other of the pair of gas shield jigs can be freely arranged. Thereby, the pair of gas shielding jigs can be arranged in accordance with the welding scene, and adsorbed oxygen and adsorbed nitrogen remaining on the surface of the welded part can be removed more reliably. Oxygen and nitrogen concentrations in the weld bead can be reduced.

(2) In the shielding step, a cover member is arranged to cover the torch and the pair of gas shielding jigs, and the injected shielding gas is retained inside the cover member. (1) The method for producing a laminate-molded article according to .
According to this method for manufacturing a laminate-molded article, the shielding gas can be retained in the space surrounding the torch within the cover member, and the formed weld bead can be reliably shielded from the atmospheric atmosphere.

(3) When the posture of the torch is changed while moving the torch while forming the weld bead, or when an obstacle exists in front of the direction of movement of the torch, the pair of gas shielding jigs The method for manufacturing a laminate-molded article according to (1) or (2), wherein at least one of the above is rotated around the torch or moved in the axial direction of the torch.
According to this method for manufacturing a laminate-molded article, by rotating or moving the gas shield jig, interference with obstacles can be prevented and the weldable range can be expanded.

(4) An apparatus for producing a laminate-molded article, which repeatedly laminates welded beads made by melting and solidifying filler material of pure titanium or titanium alloy to form a laminate-molded article,
Torch and
a torch moving mechanism that moves the torch;
a filler material supply unit that supplies the filler material to the torch;
a pair of gas shield jigs each independently provided on the torch;
a shielding gas supply unit that supplies shielding gas to the torch and the pair of gas shielding jigs;
Equipped with
The pair of gas shielding jigs is formed such that an injection port for the shielding gas supplied from the shielding gas supply unit extends in one direction from the torch,
One of the pair of gas shield jigs is disposed at the front in the direction of movement of the torch, and the other is disposed at the rear in the direction of movement of the torch.
Manufacturing equipment for additively manufactured products.
According to this additive manufacturing device, the welding part can be before-shielded by the gas shielding jig placed in front of the torch in the direction of movement, and the welding part can be after-shielded by the gas shielding jig placed at the rear in the direction of torch movement. can be done. Since both gas shield jigs are independently provided on the torch, one and the other of the pair of gas shield jigs can be freely arranged. Thereby, the pair of gas shielding jigs can be arranged in accordance with the welding scene, and adsorbed oxygen and adsorbed nitrogen remaining on the surface of the welded part can be removed more reliably. Oxygen and nitrogen concentrations in the weld bead can be reduced.

(5) comprising a cover member that covers the periphery of the torch and the pair of shield members;
The apparatus for producing a laminate-molded article according to (4), wherein the injected shielding gas is retained inside the cover member.
According to this laminate-molded product manufacturing apparatus, the shielding gas can be retained in the space surrounding the torch within the cover member, and the formed weld bead can be reliably shielded from the atmospheric atmosphere.

(6) At least one of a rotation mechanism that rotates and moves the gas shielding jig disposed in front of the torch in a moving direction around the torch, and a linear motion mechanism that moves the gas shield jig along the axis of the torch. , (4) or (5).
According to this laminate-molded product manufacturing apparatus, by rotating or moving the gas shield jig, interference with obstacles can be prevented and the weldable range can be expanded.

11 Welding robot 13 Robot controller 15 Filler metal supply section 17 Shield gas supply section 19 Welding power source 21 Control section 23 Torch 25 Base plate 27A, 27B Gas shield jig 29 Cover member 31 Support section 33 Housing 33a Opening section 35 Wire mesh 37 Adjustment Fluid 39 Gas supply pipe 41 Diffusion pipe 41a Opening 43 Internal space 45 Cover support part 47 Skeleton member 47a Support piece 47b First annular part 47c Second annular part 47d Support part 49 Sheet member 49a Opening part 49b Outer edge end 51 Torch surrounding space 55 Adsorbed oxygen/adsorbed nitrogen 57 Wall portion 100 Gas shield welding equipment (layered manufacturing equipment)
B Welding bead

Claims (4)

A method for producing a laminate-molded article, in which a laminate-molded article is manufactured by repeatedly laminating welded beads made by melting and solidifying pure titanium or titanium alloy filler material, the method comprising:
heating and melting the filler material at the tip of the torch while supplying the filler material to a torch to form a weld bead;
Injecting a shielding gas to shield the welding bead from the atmospheric atmosphere;
including;
The shielding step includes:
Injecting the shielding gas from an injection port provided at the tip of the torch,
Of a pair of gas shielding jigs that are provided independently on the torch and each of which has a shielding gas injection area extending in one direction from the torch, one of the gas shielding jigs is disposed in front of the direction of movement of the torch, and the other is placed at the rear in the direction of movement of the torch ,
disposing a cover member that covers the periphery of the torch and the pair of gas shielding jigs, and causing the injected shielding gas to stay inside the cover member;
A method for manufacturing a layered product. A method for producing a laminate-molded article, in which a laminate-molded article is manufactured by repeatedly laminating welded beads made by melting and solidifying pure titanium or titanium alloy filler material, the method comprising:
heating and melting the filler material at the tip of the torch while supplying the filler material to a torch to form a weld bead;
Injecting a shielding gas to shield the welding bead from the atmospheric atmosphere;
including;
The shielding step includes:
Injecting the shielding gas from an injection port provided at the tip of the torch,
Of a pair of gas shielding jigs that are provided independently on the torch and each of which has a shielding gas injection area extending in one direction from the torch, one of the gas shielding jigs is disposed in front of the direction of movement of the torch, and the other a step of arranging the torch at the rear in the moving direction of the torch,
When the posture of the torch is changed while the torch is moving while forming the welding bead, or when an obstacle exists in front of the torch in the direction of movement, at least one of the pair of gas shielding jigs is removed. rotating around the torch or moving it in the axial direction of the torch,
A method for manufacturing a layered product. An apparatus for producing a laminate-molded article, which repeatedly laminates welded beads made by melting and solidifying filler material of pure titanium or titanium alloy to form a laminate-molded article,
Torch and
a torch moving mechanism that moves the torch;
a filler material supply unit that supplies the filler material to the torch;
a pair of gas shield jigs each independently provided on the torch;
a shielding gas supply unit that supplies shielding gas to the torch and the pair of gas shielding jigs;
Equipped with
The pair of gas shielding jigs is formed such that an injection port for the shielding gas supplied from the shielding gas supply unit extends in one direction from the torch,
One of the pair of gas shield jigs is disposed at the front in the direction of movement of the torch, and the other is disposed at the rear in the direction of movement of the torch,
Furthermore, a cover member that covers the periphery of the torch and the pair of gas shield jigs is provided,
Retaining the injected shielding gas inside the cover member;
Manufacturing equipment for additively manufactured products. An apparatus for producing a laminate-molded article, which repeatedly laminates welded beads made by melting and solidifying filler material of pure titanium or titanium alloy to form a laminate-molded article,
Torch and
a torch moving mechanism that moves the torch;
a filler material supply unit that supplies the filler material to the torch;
a pair of gas shield jigs each independently provided on the torch;
a shielding gas supply unit that supplies shielding gas to the torch and the pair of gas shielding jigs;
Equipped with
The pair of gas shielding jigs is formed such that an injection port for the shielding gas supplied from the shielding gas supply unit extends in one direction from the torch,
One of the pair of gas shield jigs is disposed at the front in the direction of movement of the torch, and the other is disposed at the rear in the direction of movement of the torch,
Further, at least one of a rotation mechanism that rotates and moves the gas shielding jig disposed in front of the torch in a moving direction around the torch, and a linear motion mechanism that moves the gas shield jig along the axis of the torch.
Manufacturing equipment for additively manufactured products.

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