Patent Application
20240042529
The present application relates to a DED nozzle for use with an AM apparatus and an adapter detachably attachable to a DED nozzle. The present application claims priority under the Paris Convention to Japanese Patent Application No. 2021-4335 filed on Jan. 14, 2021. The entire disclosure of Japanese Patent Application No. 2021-4335 including the specification, the claims, the drawings, and the abstract is incorporated herein by reference in its entirety.
There are known techniques for directly fabricating a three-dimensional object based on three-dimensional data on a computer that expresses the three-dimensional object. Known examples thereof include the Additive Manufacturing (AM) technique. As one example thereof, Direct Energy Deposition (DED) is available as the AM technique employing the deposition method. DED is a technique that carries out fabrication by melting and solidifying a metal material together with a base material using an appropriate heat source while supplying the metal material locally. Further, Powder Bed Fusion (PBF) is available as one example of the AM technique. In PBF, each layer of the three-dimensional object is fabricated by subjecting two-dimensionally bedded metal powder to irradiation of a fabrication target portion thereof with a laser beam or an electron beam serving as a heat source, and melting and solidifying or sintering the metal powder. In PBF, the desired three-dimensional object can be fabricated by repeating such a process.
Each layer of the three-dimensional object can also be fabricated by emitting a laser beam toward metal powder or onto metal powder using the DED nozzle after two-dimensionally bedding the metal powder like PBF. However, in such a case, generally, the DED nozzle carries out the fabrication while supplying a powder material used as the material and carrier gas from the DED nozzle, thereby unintentionally blowing off the metal powder bedded in advance due to the supply of the carrier gas and thus undesirably making the planned fabrication difficult. One of objects of the present application is to provide a technique for carrying out fabrication on a powder material bedded in advance using a DED nozzle.
According to one aspect, a DED nozzle for use with an AM apparatus is provided. This DED nozzle includes a DED nozzle main body, a laser port provided at a distal end of the DED nozzle main body and configured to emit laser light, a laser passage provided in communication with the laser port and configured to allow the laser light to pass through inside the DED nozzle main body, a powder port provided at the distal end of the DED nozzle main body and configured to eject a powder material, and a powder passage provided in communication with the powder port and configured to allow the powder material to pass through inside the DED nozzle main body. Directions of the powder passage and the powder port are determined based on a distance from the powder port to a fabrication point, a velocity of the powder material ejected from the powder port, and a gravitational acceleration.
In the following description, embodiments of an AM apparatus for manufacturing a fabrication object, a DED nozzle for use with the AM apparatus, and an adapter detachably attachable to the DED nozzle according to the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same or similar components will be indicated by the same or similar reference numerals, and redundant descriptions regarding the same or similar components may be omitted in the description of each of the embodiments. Further, features described in each of the embodiments are also applicable to other embodiments in so far as they do not contradict each other.
In one embodiment, the AM apparatus 100 includes a DED head 200 as illustrated in
The DED head 200 can be an arbitrary DED head, and, for example, a known DED head can be used as it. The DED head 200 is coupled with a movement mechanism 220, and is movably configured. The movement mechanism 220 can be an arbitrary movement mechanism, and, for example, may be a movement mechanism capable of moving the DED head 200 along a specific axis such as a rail or may be constituted by a robot capable of moving the DED head 200 to an arbitrary position and in an arbitrary direction. As one embodiment, the movement mechanism 220 can be configured to be able to move the DED head 200 along perpendicular three axes.
The AM apparatus 100 according to one embodiment includes a control device 170 as illustrated in
Further, the DED nozzle main body 259 includes a second passage 254 outside the first passage 252. The powder material supplied from the powder material source 204 and the carrier gas supplied from the gas source 206 and used to transport the powder material pass through the second passage 254. After passing through the second passage 254, the powder material is ejected from a powder port 254a. In one embodiment, the second passage 254 can be a passage having a cross-section shaped like a single ring surrounding the first passage 252. Alternatively, in one embodiment, the second passage 254 can be a plurality of passages having a circular cross-section arranged so as to surround the first passage 252. In one embodiment, the second passage 254 may have a triangular shape or a quadrilateral shape in cross-section. For example, a small passage can be easily manufactured by employing such a structure that the DED nozzle main body 259 can be divided into an inner body and an outer body with a border therebetween placed along the second passage 254 and machining a groove serving as the second passage 254 on a surface where the inner body and the outer body are in contact with each other.
The carrier gas can be inertial gas, such as argon gas or nitrogen gas. Argon gas heavier than air is further desirably used as the carrier gas. Using the inertial gas heavier than air as the carrier gas allows a molten pool formed from the melted powder material at and near a fabrication point 253 to be covered with the inertial gas, thereby contributing to preventing the molten pool and the fabrication object from being oxidized.
In another embodiment, further, the DED nozzle main body 259 may include a third passage and a gas port outside the second passage 254. Shield gas passes through the third passage. The shield gas is discharged from the gas port after passing through the third passage. In the case where the DED nozzle 250 includes the third passage, the third passage may be a passage having a cross-section shaped like a single ring surrounding the first passage 252 and the second passage 254, or may be a plurality of passages having a circular cross-section arranged so as to surround the first passage 252 and the second passage 254.
Generally, the DED nozzle 250 is designed in such a manner that the laser 251 emitted from the laser port 252a and the powder material ejected from the powder port 254a are converged at the fabrication point 253.
a vertical distance: y [m]
a horizontal distance: x [m],
a gravitational acceleration: g [m/s2],
an angle at which the powder material is ejected from the DED nozzle 250: θ [deg], and
a velocity at which the powder material is ejected from the DED nozzle 250: V [m/s].
After time t [s] since some powder particle is ejected from the powder material 254a, the position of the powder particle can be expressed by the following equations.
x=X(t)=Vt×sin(θ)
y=Y(t)=−{(g/2)t2+Vt cos(θ)}
In this case, t=0 is the time point at which the powder particle is ejected from the powder port 254a of the DED nozzle 250. The velocity V at which the powder material is ejected from the DED nozzle 250 is assumed to be equal to the velocity at which the carrier gas is ejected from the powder port 254a. Further, the angle θ at which the powder material is ejected is an angle with respect to the vertical direction.
For example, when the powder material is ejected from the DED nozzle 250 at a sufficiently high velocity V [m/s], this leads to Vtcos(θ)>>(g/2)t2, and therefore the powder material is little gravitationally affected and the powder particle takes a trajectory substantially expressed by the following equations.
x=X(t)=Vt×sin(θ)
y=Y(t)=−Vt cos(θ)
More specifically, the DED nozzle 250 is designed in such a manner that the respective extensions of the first passage 252, through which the laser 251 passes, and the second passage 254, through which the powder material passes, intersect at the fabrication point 253, as indicated by a broken line in
However, when the powder material is ejected from the DED nozzle 250 at a low velocity V [m/s], the powder material is gravitationally affected and the powder particle takes a trajectory expressed by the following equations.
x=X(t)=Vt×sin(θ)
y=Y(t)=−{(g/2)t2+Vt cos(θ)}
More specifically, the trajectory of the powder particle is drawn as indicated by a long dashed short dashed line in
As one example,
the vertical distance: −20 mm and
the horizontal distance: 7.25 mm,
and the powder material is ejected under conditions of
the velocity of the particle: V=20 [m/s],
the ejection angle of the particle: θ=20 [deg], and
the gravitational acceleration: g=9.8 [m/s2].
Further,
As illustrated in
On the other hand, as illustrated in
In light thereof, in the present disclosure, in the DED nozzle 250 that supplies the carrier gas and the powder material at a relatively low velocity, the angle at which the powder material is ejected from the DED nozzle is designed in consideration of the gravitational influence so as to allow the powder material to be appropriately supplied to the fabrication point 253. More specifically, the angle θ [deg] at which the powder material is ejected from the DED nozzle 250, i.e., the directions of the powder port 254a and the second passage 254 are determined so as to allow the powder particle to pass through the fabrication point 253 based on the above-described equations according to the position of the fabrication point 253 and the ejection velocity V of the powder particle.
In the DED nozzle 250 according to the embodiment illustrated in
As one example, in a case where the DED nozzle 250 has the fabrication point 253 located at the following distance from the powder port 254a of the DED nozzle 250,
the vertical distance: −20 mm and
the horizontal distance: 7.25 mm,
and has the velocity at which the powder material is ejected from the DED nozzle 250: V=1.0 [m/s],
ejection at θ=22 [deg] allows the laser and the powder particle to intersect at the fabrication point 253.
As one example, in a case where the DED nozzle 250 has the fabrication point 253 located at the following distance from the powder port 254a of the DED nozzle 250,
the vertical distance: −20 mm and
the horizontal distance: 7.25 mm,
and has the velocity at which the powder material is ejected from the DED nozzle 250: V=0.5 [m/s],
ejection at θ=27 [deg] allows the laser and the powder particle to intersect at the fabrication point 253.
As one example, in a case where the DED nozzle 250 has the fabrication point 253 located at the following distance from the powder port 254a of the DED nozzle 250,
the vertical distance: −20 mm and
the horizontal distance: 7.25 mm,
and has the velocity at which the powder material is ejected from the DED nozzle 250: V=[m/s],
ejection at 0=45 [deg] allows the laser and the powder particle to intersect at the fabrication point 253.
As one example, in a case where the DED nozzle 250 has the fabrication point 253 located at the following distance from the powder port 254a of the DED nozzle 250,
the vertical distance: −20 mm and
the horizontal distance: 7.25 mm,
and has the velocity at which the powder material is ejected from the DED nozzle 250: V=[m/s],
ejection θ=59 [deg] allows the laser and the powder particle to intersect at the fabrication point 253.
In this manner, the powder material can be appropriately supplied to the fabrication point 253 by designing the angle θ at which the powder material is ejected from the DED nozzle 250 according to the fabrication point 253 and the velocity V at which the powder material is ejected from the DED nozzle 250. More specifically, the powder material can be ejected from the DED nozzle 250 at the above-described angle θ [deg] by configuring the DED nozzle 250 in such a manner that the direction of the second passage 254 immediately before the powder port 254a matches the above-described θ [deg] with respect to the vertical direction.
The above-described embodiments have been illustrated and described indicating that the powder material and the laser emitted from the DED nozzle 250 intersect at the fabrication point 253, but may be designed in such a manner that the powder material and the laser intersect slightly above the fabrication point 253. For example, in one embodiment, the DED nozzle 250 can be designed in such a manner that the powder material and the laser intersect at a position above the above-described fabrication point 253 by a distance approximately one time to three times as long as the irradiation width of the laser at the above-described fabrication point 253. As one example, in a case where the width of the laser (FWHM, 1/e2, or the like) is approximately 2 mm at the fabrication point 253, the DED nozzle 250 can be designed in such a manner that the powder material and the laser intersect at a position above the fabrication point 523 by approximately 2 mm to approximately 6 mm. The intersection of the powder material and the laser at a position slightly above the fabrication point 253 causes heat to be applied to the powder material to melt it at the position slightly above the fabrication point 253, thereby allowing the melted material to be supplied to the fabrication point 253.
The above-described embodiments allow the powder material to be supplied from the DED nozzle 250 to the fabrication point 253 even when the carrier gas and the powder material are supplied from the DED nozzle 250 at such a low flow velocity V that the carrier gas ejected from the DED nozzle 250 is prevented from blowing off the powder bedded in advance in the case where the AM fabrication is carried out with the powder disposed at the fabrication point 253 or near the fabrication point 253 in advance. Preferably, the carrier gas is supplied at a flow velocity equal to or lower than approximately 1 m/s as the flow velocity V low enough to prevent the carrier gas from blowing off the powder bedded in advance. Further, more preferably, the flow velocity of the carrier gas ejected from the DED nozzle 250 is from approximately 0.3 m/s to approximately 0.1 m/s.
In the AM fabrication using the DED nozzle 250, the velocity at which the powder material is ejected may be desired to be changed according to the location where the fabrication is carried out, the material, and/or the like, in some cases. However, changing the ejection velocity V of the powder material may lead to a failure to appropriately supply the powder material to the fabrication point 253 as described above. It is costly to prepare a plurality of DED nozzles equipped with differently directed second passages 254 through which the powder material and the carrier gas pass according to the velocity V at which the powder material is ejected.
In light thereof, the present disclosure discloses an adapter 300 detachably attachable to the distal end of a DED nozzle in one embodiment.
The adapter 300 has a generally ring-like shape, and is shaped and structured detachably attachably to the distal end of the DED nozzle 250. The adapter 300 includes an adapter laser passage 302, which is brought into communication with the first passage 252 through which the laser passes in the DED nozzle 250 when the adapter 300 is attached to the DED nozzle 250. Further, the adapter 300 includes an adapter powder passage 304, which is brought into communication with the second passage 254 through which the carrier gas and the powder material pass in the DED nozzle 250 when the adapter 300 is attached to the DED nozzle 250. The laser 251 is emitted from an adapter laser port 302a of the adapter 300 after passing through the first passage 252 of the DED nozzle 250 and the adapter laser passage 302 of the adapter 300. Further, the carrier gas and the powder material are ejected from an adapter powder port 304a of the adapter 300 after passing through the second passage 254 of the DED nozzle 250 and the adapter powder passage 304 of the adapter 300.
The direction of the adapter powder passage 304 of the adapter 300 (the angle θ [deg] with respect to the vertical direction) is determined according to the position of the fabrication point 253 and the velocity V at which the powder material is ejected from the DED nozzle 250 as described above. Therefore, the angle θ at which the powder material is ejected from the DED nozzle 250 can be changed by preparing a plurality of adapters 300 equipped with the adapter powder passages 304 extending in different directions and changing the adapter 300 even for the same DED nozzle 250.
In the case where the DED nozzle 250 includes the third passage through which the shield gas passes, the adapter 300 may include an adapter shield gas passage in communication with the third passage of the DED nozzle 250.
At least the following technical ideas can be recognized from the above-described embodiments.
[Configuration 1] According to a configuration 1, a DED nozzle for use with an AM apparatus is provided. This DED nozzle includes a DED nozzle main body, a laser port provided at a distal end of the DED nozzle main body and configured to emit laser light, a laser passage provided in communication with the laser port and configured to allow the laser light to pass through inside the DED nozzle main body, a powder port provided at the distal end of the DED nozzle main body and configured to eject a powder material, and a powder passage provided in communication with the powder port and configured to allow the powder material to pass through inside the DED nozzle main body. Directions of the powder passage and the powder port are determined based on a distance from the powder port to a fabrication point, a velocity of the powder material ejected from the powder port, and a gravitational acceleration.
[Configuration 2] According to a configuration 2, in the DED nozzle according to the configuration 1, the directions of the powder passage and the powder port are determined while the velocity of the powder material ejected from the powder port is 0.3 m/s or lower.
[Configuration 3] According to a configuration 3, the DED nozzle according to the configuration 1 or 2 is configured in such a manner that powder ejected from the powder port and the laser emitted from the laser port intersect at the fabrication point or intersect at a position higher than the fabrication point.
[Configuration 4] According to a configuration 4, an adapter detachably attachable to a DED nozzle for use with an AM apparatus is provided. This adapter includes an adapter laser passage configured to be brought into communication with a laser passage of the DED nozzle when the adapter is attached to the DED nozzle, an adapter laser port configured to emit a laser that passes through the adapter laser passage, an adapter powder passage configured to be brought into communication with a powder passage of the DED nozzle when the adapter is attached to the DED nozzle, and an adapter powder port configured to eject a powder material that passes through the adapter powder passage. Directions of the adapter powder passage and the adapter powder port are determined based on a distance from the adapter powder port to a fabrication point, a velocity of the powder material ejected from the adapter powder port, and a gravitational acceleration.
[Configuration 5] According to a configuration 5, in the adapter according to the configuration 4, the directions of the adapter powder passage and the adapter powder port are determined while the velocity of the powder material ejected from the adapter powder port is 0.3 m/s or lower.
[Configuration 6] According to a configuration 6, the adapter according to the configuration 4 or 5 is configured in such a manner that powder ejected from the adapter powder port and the laser emitted from the adapter laser port intersect at the fabrication point or intersect at a position higher than the fabrication point.
[Configuration 7] According to a configuration 7, a method for designing a DED nozzle for use with an AM apparatus is provided. This method includes determining a direction of a powder port provided at a distal end of a DED nozzle main body and configured to eject a powder material and a direction of a powder passage provided in communication with the powder port and configured to allow the powder material to pass through inside the DED nozzle main body based on a distance from the powder port to a fabrication point, a velocity of the powder material ejected from the powder port, and a gravitational acceleration.
[Configuration 8] According to a configuration 8, in the method according to the configuration 7, the directions of the powder passage and the powder port are determined while the velocity of the powder material ejected from the powder port is 0.3 m/s or lower.
[Configuration 9] According to a configuration 9, in the method according to the configuration 7 or 8, the directions of the powder passage and the powder port are determined in such a manner that powder ejected from the powder port and a laser emitted from a laser port intersect at the fabrication point or intersect at a position higher than the fabrication point.
[Configuration 10] According to a configuration 10, a method for designing an adapter detachably attachable to a DED nozzle for use with an AM apparatus is provided. This method includes determining a direction of an adapter powder port configured to eject a powder material and a direction of an adapter powder passage in communication with the adapter powder port in a state that the adapter is attached to a distal end of a DED nozzle main body based on a distance from the adapter powder port to a fabrication point, a velocity of the powder material ejected from the adapter powder port, and a gravitational acceleration.
[Configuration 11] According to a configuration 11, in the method according to the configuration 10, the directions of the adapter powder passage and the adapter powder port are determined while the velocity of the powder material ejected from the adapter powder port is 0.3 m/s or lower.
[Configuration 12] According to a configuration 12, in the method according to the configuration 10 or 11, the directions of the adapter powder passage and the adapter powder port are determined in such a manner that powder ejected from the adapter powder port and a laser emitted from an adapter laser port intersect at the fabrication point or intersect at a position higher than the fabrication point.
[Configuration 13] According to a configuration 13, an AM apparatus is provided. This AM apparatus includes the DED nozzle according to any one of the configurations 1 to 3 or the adapter according to any one of the configurations 4 to 6.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-004335 | Jan 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/042411 | 11/18/2021 | WO |
