JP7438888B2 - AM device - Google Patents

Description

The present application relates to AM devices.

2. Description of the Related Art There is a known technology for directly modeling a three-dimensional object from three-dimensional data on a computer that represents the three-dimensional object. For example, Additive Manufacturing (AM) methods are known. As an example, there is direct energy deposition (DED) as a deposition type AM method. DED is a technology that performs modeling by locally supplying a metal material and melting and solidifying it together with a base material using an appropriate heat source. Further, as an example of the AM method, there is powder bed fusion (PBF). PBF creates each layer of a three-dimensional object by irradiating a two-dimensional spread of metal powder with a laser beam or electron beam, which is a heat source, to melt, solidify, or sinter the metal powder. to form. With PBF, a desired three-dimensional object can be modeled by repeating such steps.

US Patent No. 4,724,299 Special table 2019-500246 publication

When modeling is performed using the above-mentioned DED or PBF, the vicinity of the modeling location may be purged with an inert gas in order to lower the oxygen concentration in the modeling location. At this time, if the flow rate of the purge gas is high, the flow of the material powder and carrier gas due to DED may be disturbed, making the modeling unstable. Furthermore, if a purge gas is used in PBF, the material powder that has been spread in advance may be blown away, making it difficult to perform the planned modeling. On the other hand, if the flow rate of the purge gas is low, oxygen in the modeling area may not be sufficiently removed. One object of the present application is to provide a structure of an AM device that can sufficiently lower the oxygen concentration in the modeling area while maintaining the flow rate of purge gas at an appropriate level during modeling using the AM method.

An AM device for manufacturing a shaped object is provided, the AM device includes a DED nozzle, and the DED nozzle includes a DED nozzle body and a laser beam provided at the tip of the DED nozzle body for emitting a laser beam. a laser port, a laser passage for a laser beam to pass through the DED nozzle body, which communicates with the laser port, and a powder port provided at the tip of the DED nozzle main body for emitting a powder material. , and a powder passage for a powder material to pass through the DED nozzle body, which communicates with the powder port, and the AM device further includes a powder passage that communicates with the laser port of the DED nozzle and the powder material a cover that surrounds the mouth and is open on the downstream side in the direction in which the laser beam is emitted; the cover has a gas supply path for supplying gas to the inside of the cover; A supply channel is oriented to direct gas generally toward the DED nozzle body, and the gas supply channel includes a lattice structure layer.

1 is a diagram schematically illustrating an AM apparatus for manufacturing a shaped object, according to an embodiment; FIG. 1 schematically illustrates a cross-section of a DED nozzle according to one embodiment; FIG. FIG. 4 schematically illustrates a cross-section of a cover attached to a DED nozzle according to one embodiment. FIG. 4 is a perspective view of the cover shown in FIG. 3 when viewed diagonally from above. FIG. 4 is a top view of a portion of the cover shown in FIG. 3 viewed from above. FIG. 3 is a perspective view of the inner cover alone, according to one embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an AM apparatus for manufacturing a shaped article according to the present invention will be described below with reference to the accompanying drawings. In the accompanying drawings, the same or similar elements are denoted by the same or similar reference numerals, and redundant description of the same or similar elements may be omitted in the description of each embodiment. Furthermore, features shown in each embodiment can be applied to other embodiments as long as they do not contradict each other.

FIG. 1 is a diagram schematically illustrating an AM apparatus for manufacturing a shaped object, according to one embodiment. As shown in FIG. 1, the AM device 100 includes a base plate 102. The object M will be formed on the base plate 102. The base plate 102 can be a plate made of any material that can support the shaped object M. In one embodiment, base plate 102 is placed on top of XY stage 104. The XY stage 104 is a stage 104 that is movable in two orthogonal directions (x direction and y direction) within a horizontal plane. Note that the XY stage 104 may be connected to a lift mechanism that is movable in the height direction (z direction). Also, in one embodiment, the XY stage 104 may be omitted.

In one embodiment, as shown in FIG. 1, AM device 100 includes a DED head 200. DED head 200 is connected to a laser source 202, a material powder source 204, and a gas source 206. DED head 200 has DED nozzle 250. DED nozzle 250 is configured to inject laser, material powder, and gas from laser source 202, material powder source 204, and gas source 206. In one embodiment, a cover 300 is attached to the DED nozzle 250 as shown in FIG. The cover 300 is configured to surround the injection port of the DED nozzle 250.

The DED head 200 can be of any type, for example, a known DED head can be used. The DED head 200 is connected to a moving mechanism 220 and is configured to be movable. The movement mechanism 220 may be arbitrary, for example, may be capable of moving the DED head 200 along a particular axis such as a rail, or may move the DED head 200 to any position and orientation. It may also consist of a robot that can In one embodiment, the moving mechanism 220 can be configured to move the DED head 200 along three orthogonal axes.

AM device 100 according to one embodiment includes a control device 170 as shown in FIG. The control device 170 is configured to control various operating mechanisms of the AM device 100, such as the above-described DED head 200 and various operating mechanisms. Control device 170 can be constructed from a general computer or a special purpose computer.

FIG. 2 is a schematic cross-sectional diagram of a DED nozzle 250 according to one embodiment. DED nozzle 250 according to the illustrated embodiment includes a DED nozzle body 259 that is generally frustoconically shaped. DED nozzle 250 according to the illustrated embodiment includes a laser passage 252 in the center of DED nozzle body 259 through which laser 251 passes. The laser passing through the laser path 252 is emitted from the laser port 252a of the DED nozzle body 259. Further, the DED nozzle body 259 includes a powder passage 254 outside the laser passage 252 through which material powder and a carrier gas for transporting the material powder pass. The material powder that has passed through the powder passage 254 is discharged from the powder port 254a. Further, the DED nozzle body 259 includes a shield gas passage 256 outside the powder passage 254 through which the shield gas passes. The shielding gas that has passed through the shielding gas passage 256 is released from the gas port 256a.

The powder passage 254 is configured so that the material powder discharged from the DED nozzle 250 is focused at substantially the same position as the focal point 251a of the laser 251. In addition, in FIG. 2, the flow of material powder and carrier gas is shown by broken lines. The carrier gas can be an inert gas such as argon gas or nitrogen gas. It is more desirable to use argon gas, which is heavier than air, as the carrier gas. Note that by using an inert gas as the carrier gas, oxidation can be prevented by covering the molten pool formed by melting the material powder with the inert gas. However, air outside the powder port 254a may be drawn in by the flow of the carrier gas released from the powder port 254a. Therefore, the DED nozzle 250 shown in FIG. 2 supplies the shielding gas at a low speed from the shielding gas passage 256 disposed outside the powder passage 254 through which the powder material and carrier gas are discharged, thereby reducing the amount of air in the surrounding air. can be prevented from getting caught. By preventing surrounding air (particularly oxygen) from being drawn in by the carrier gas, it is possible to suppress the formation of a metal oxide film during modeling, and it is also possible to form a molten pool with good wettability. In FIG. 2, the flow of shielding gas is indicated by arrows. Note that the shield gas can be the same type of gas as the carrier gas.

FIG. 3 is a schematic cross-sectional view of a cover 300 attached to a DED nozzle 250 according to one embodiment. FIG. 4 is a perspective view of the cover 300 shown in FIG. 3 viewed diagonally from above. FIG. 5 is a top view of a portion of the cover 300 shown in FIG. 3, viewed from above.

As shown in FIGS. 3 and 4, cover 300 includes an inner cover 302 and an outer cover 304. As shown in FIGS. The inner cover 302 has a substantially cylindrical shape, and the lower side of the inner cover 302 is open. The inner cover 302 is arranged to surround the laser port 252a, powder port 254a, and gas port 256a of the DED nozzle 250. The outer cover 304 is arranged to surround the inner cover 302 at intervals, and has a substantially cylindrical shape with a larger diameter than the inner cover 302. Like the inner cover 302, the outer cover 304 is also open at the bottom.

The inner cover 302 and the outer cover 304 are connected by a connecting member 306. The connecting member 306 is a protrusion extending outward from the inner cover 302. The inner cover 302 and the outer cover 304 are connected by fitting these protrusions into recesses formed in the outer cover 304.

In the embodiment shown in FIG. 3, the cover 300 includes a first top cover 310 and a second top cover 312. The first upper cover 310 is connected to the upper end of the inner cover 302. Note that the inner cover 302 and the first upper cover 310 may be an integral structure, or may be formed as separate members and connected to each other. The second upper cover 312 is arranged above the first upper cover 310.

The first upper cover 310 and the second upper cover 312 include a center hole 320 through which the nozzle body 259 of the DED nozzle 250 passes. As shown in FIG. 3, the center hole 320 is larger than the diameter of the nozzle body 259, and the side surfaces of the nozzle body 259 do not contact the first upper cover 310 and the second upper cover 312. As shown in FIG. 3, by engaging the shoulder portion 257 of the nozzle body 259 with the second upper cover 312, the side surface of the nozzle body 259 can be prevented from coming into contact with the first upper cover 310 and the second upper cover 312. , the cover 300 can be positioned over the DED nozzle 250 such that the tip of the DED nozzle 250 is disposed inside the cover 300.

A gas supply path 314 is defined between the first upper cover 310 and the second upper cover 312. The second upper cover 312 is provided with a gas supply port 316 for supplying purge gas to the gas supply path 314. The gas supply port 316 is arranged near the outside of the second upper cover 312, that is, near the inner cover 302. The purge gas supplied from the gas supply port 316 flows generally toward the DED nozzle 250 through the gas supply path 314 . As described above, since there is a gap between the center hole 320 of the first upper cover 310 and the second upper cover 312 and the side surface of the nozzle body 259, the purge gas that has passed through the gas supply path 314 flows to the side surface of the nozzle body 259. Further, purge gas is supplied into the space surrounded by the inner cover 302 and the first upper cover 310.

Note that the purge gas supplied from the gas supply port 316 can be, for example, an inert gas such as argon gas or nitrogen gas. It is more desirable to use argon gas, which is heavier than air, as the purge gas. As the purge gas supplied from the gas supply port 316, the same type of gas as the carrier gas and shield gas described above can be used.

In one embodiment, gas supply passageway 314 includes a lattice structure layer 330. In one embodiment, the lattice structure layer 330 includes a plurality of pillars 332 disposed in the gas supply passageway 314. In the embodiment shown in FIG. 3, the plurality of pillars 332 are cylindrical pillars 332 extending from the first upper cover 310 toward the second upper cover. In one embodiment, the first upper cover 310 including the plurality of columns 332 is formed by an AM method or any other method. Further, in one embodiment, the second upper cover 312 including the plurality of columns 332 may be formed by the AM method or any other arbitrary method. Alternatively, the lattice structure layer 330 including the plurality of pillars 332 may be formed as a separate member from the first upper cover 310 and the second upper cover 312 by any method including the AM method.

In one embodiment, the plurality of pillars 332 are arranged sparsely on the inlet side of the gas supply path 314 and densely arranged on the outlet side. For example, as shown in FIG. 5, by providing a large number of rows of a plurality of columns 332 lined up in the radial direction, the columns 332 become dense on the radially inner side, which is the outlet side of the gas supply path 314, and the gas supply port 316 is The pillars 332 may be arranged sparsely on the outside in the radial direction. In the embodiment shown in FIG. 5, the cross section of the column 332 is circular, but in other embodiments, the cross section of the column 332 may be any shape such as a polygon such as a quadrangle or a triangle, or a cross. can.

In the embodiment described above, since the gas supply path 314 includes the lattice structure layer 330, the purge gas supplied from the gas supply port 316 passes through the gas supply path 314 while being diffused in the lattice structure layer 330, and passes through the first upper layer. It is gently supplied toward the DED nozzle 250 from the center hole 320 of the cover 310 and the second upper cover 312. Therefore, the cover 300 can lower the oxygen concentration in the modeling area while appropriately reducing the flow rate of the purge gas.

In one embodiment, cover 300 includes a cooling mechanism to cool cover 300. FIG. 6 is a perspective view showing the inner cover 302 alone. In one embodiment, as shown in FIG. 3, the inner cover 302 includes refrigerant passages 340 for flowing refrigerant therein. The refrigerant passage 340 extends circumferentially around the cylindrical inner cover 302 . The cover 300 also includes a refrigerant supply port 342 for supplying refrigerant to the refrigerant passage 340. In the embodiment shown in FIG. 3, the refrigerant supply port 342 may be an opening formed in one of the connecting members 306 that connect the inner cover 302 and the outer cover 304 described above. The inner cover 302 also includes a refrigerant discharge port 344 for discharging the refrigerant from the refrigerant passage 340. In the embodiment shown in FIG. 6, the refrigerant outlet 344 is formed at the upper end of the inner cover 302.

The refrigerant supply port 342 and the refrigerant discharge port 344 are connected to a refrigerant supply line that includes a heat exchanger, a pump, and the like (not shown). The refrigerant supplied from the refrigerant supply port 342 passes through the refrigerant passage 340 formed in the inner cover 302 and is discharged from the refrigerant discharge port 344 . The inner cover 302 is cooled by the refrigerant passing through the refrigerant passage 340 .

When modeling is performed using the DED nozzle 250 provided with the cover 300, the reflected energy of the laser irradiated to the object M is received by the DED nozzle 250 and the cover 300, particularly the inner cover 302. Furthermore, since the inside of the cover 300 is purged with inert gas, the flow of gas in the cover 300 around the DED nozzle 250 becomes gentle. Therefore, the temperatures of the DED nozzle 250 and the cover 300 tend to rise during modeling, which may make the modeling unstable. By providing the cover 300 with a cooling mechanism as in the above-described embodiment, it is possible to suppress the temperature rise of the DED nozzle 250 and the cover 300 during modeling. Note that as the refrigerant, for example, pure water or other liquid can be used.

In one embodiment, the wall surface of the refrigerant passage 340 may be provided with irregularities. By providing unevenness on the wall surface of the refrigerant passage, the heat exchange area by the refrigerant can be increased, and the efficiency of use of the refrigerant can be increased. Further, in one embodiment, the refrigerant passage 340 may have a lattice structure. The lattice structure may be any structure as long as it can increase the heat exchange area within the refrigerant passage 340; for example, it may be a structure with a plurality of columns arranged within the refrigerant passage 340, or it may have a mesh structure inside the refrigerant passage 340. You can also do this.

In one embodiment, the inner cover 302 with the coolant passages 340 can be manufactured from any material such as metal or plastic by an AM process or any other method.

Also, in one embodiment, the cooling mechanism may use a cooling element such as a Peltier element without using a refrigerant and a refrigerant passage. For example, a Peltier element may be attached to the inner cover 302 or the DED nozzle 250.

In one embodiment, a thermometer may be provided on the DED nozzle 250 or the inner cover 302. In one embodiment, the temperature of the DED nozzle 250 or the inner cover 302 can be maintained constant by controlling the cooling mechanism according to the temperature measured with a thermometer.

At least the following technical idea can be understood from the above-described embodiments.
[Form 1] An AM device for manufacturing a shaped object is provided, and the AM device includes a DED nozzle, and the DED nozzle includes a DED nozzle body and a laser beam provided at the tip of the DED nozzle body. a laser port for emitting a laser beam; a laser path communicating with the laser port for passing a laser beam within the DED nozzle body; and a laser path for emitting a powder material provided at the tip of the DED nozzle body. a powder port of the DED nozzle, and a powder passage communicating with the powder port for a powder material to pass through the DED nozzle body; and a cover that surrounds the powder port and is open on the downstream side in the emission direction of the laser beam, and the cover has a gas supply path for supplying gas to the inside of the cover. and the gas supply passageway is oriented to direct gas generally toward the DED nozzle body, and the gas supply passageway includes a lattice structure layer.

[Form 2] According to Form 2, in the AM device according to Form 1, the lattice structure layer includes a plurality of pillar structures.

[Form 3] According to Form 3, in the AM device according to Form 2, the lattice structure layer has a plurality of pillar structures that are sparsely arranged on the entrance side of the gas supply path and densely arranged on the exit side. It is located.

[Form 4] According to Form 4, an AM device for manufacturing a modeled object is provided, and the AM device includes a DED nozzle, and the DED nozzle includes a DED nozzle body and a tip of the DED nozzle body. a laser port for emitting a laser beam provided in the DED nozzle body; a laser path communicating with the laser port for the laser beam to pass through the DED nozzle body; and a powder provided at the tip of the DED nozzle body. a powder port for ejecting the powder material; and a powder passage communicating with the powder port and allowing the powder material to pass through the DED nozzle body; The DED nozzle has a cover that surrounds the laser port and the powder port and is open on the downstream side in the emission direction of the laser beam, and the cover is for supplying gas to the inside of the cover. a gas supply passageway, the gas supply passageway being oriented generally to direct gas toward the DED nozzle body, and the cover having a cooling mechanism for cooling the cover.

[Embodiment 5] According to embodiment 5, in the AM device according to embodiment 4, the cooling mechanism of the cover has a refrigerant passage through which a refrigerant passes.

[Embodiment 6] According to Embodiment 6, in the AM device according to Embodiment 5, the refrigerant passage is formed in a side wall of the cover.

[Embodiment 7] According to embodiment 7, in the AM device according to embodiment 5 or 6, the refrigerant passage has an uneven structure on the surface of the refrigerant passage.

[Embodiment 8] According to embodiment 8, in the AM device according to any one of embodiments 5 to 7, the refrigerant passage has a lattice structure.

[Embodiment 9] According to embodiment 9, in the AM device according to any one of embodiments 4 to 8, the cooling mechanism of the cover includes a Peltier element.

DESCRIPTION OF SYMBOLS 100...AM device 170...Control device 200...DED head 202...Laser source 204...Material powder source 206...Gas source 250...DED nozzle 252...Laser passage 254...Powder passage 256...Shield gas passage 257...Shoulder part 259... Nozzle body 300... Cover 302... Inner cover 304... Outer cover 306... Connection member 310... First upper cover 312... Second upper cover 314... Gas supply path 316... Gas supply port 320... Center hole 330... Lattice structure layer 332... Pillar 340... Refrigerant passage 342... Refrigerant supply port 344... Refrigerant discharge port M... Modeling object

Claims (9)

An AM device for manufacturing a modeled object, the AM device comprising:
having a DED nozzle, the DED nozzle comprising:
DED nozzle body,
a laser port provided at the tip of the DED nozzle body for emitting laser light, and a laser path communicating with the laser port for the laser light to pass through the DED nozzle body;
a powder port provided at the tip of the DED nozzle body for ejecting the powder material; and a powder passage communicating with the powder port for the powder material to pass through the DED nozzle body; has
The AM device further includes a cover that surrounds the laser port and the powder port of the DED nozzle and is open on the downstream side in the emission direction of the laser beam,
The cover has a gas supply path for supplying gas to the inside of the cover, the gas supply path being oriented generally to direct gas toward the DED nozzle body, and the gas supply path being oriented generally to direct gas toward the DED nozzle body. the supply channel includes a lattice structure layer;
AM device. The AM device according to claim 1,
The lattice structure layer includes a plurality of columnar structures.
AM device. The AM device according to claim 2,
In the lattice structure layer, the plurality of columnar structures are arranged sparsely on the entrance side of the gas supply path and densely arranged on the exit side.
AM device. An AM device for manufacturing a modeled object, the AM device comprising:
having a DED nozzle, the DED nozzle comprising:
DED nozzle body,
a laser port for emitting laser light provided at the tip of the DED nozzle body; and a laser path for the laser light to pass through the DED nozzle body, communicating with the laser port;
a powder port provided at the tip of the DED nozzle body for ejecting the powder material; and a powder passage communicating with the powder port for the powder material to pass through the DED nozzle body; has
The AM device further includes a cover that surrounds the laser port and the powder port of the DED nozzle and is open on the downstream side in the emission direction of the laser beam,
the cover has a gas supply passage for supplying gas to the inside of the cover, the gas supply passage being oriented generally to direct gas toward the DED nozzle body;
The cover has a cooling mechanism for cooling the cover.
AM device. The AM device according to claim 4,
The cooling mechanism of the cover has a refrigerant passage for passing a refrigerant.
AM device. The AM device according to claim 5,
The refrigerant passage is formed in a side wall of the cover.
AM device. The AM device according to claim 5 or 6,
The refrigerant passage has an uneven structure on the surface of the refrigerant passage.
AM device. The AM device according to claims 5 to 7,
The refrigerant passage has a lattice structure,
AM device. The AM device according to claims 4 to 8,
The cooling mechanism of the cover includes a Peltier element.
AM device.

Images