CN108723364B

CN108723364B - Powder supply device for 3D shape manufacturing

Info

Publication number: CN108723364B
Application number: CN201810199505.3A
Authority: CN
Inventors: 李畅佑; 河兑垀; 许世坤
Original assignee: Korea Institute of Machinery and Materials KIMM
Current assignee: Korea Institute of Machinery and Materials KIMM
Priority date: 2017-04-18
Filing date: 2018-03-12
Publication date: 2021-06-15
Anticipated expiration: 2038-03-12
Also published as: KR101966954B1; CN108723364A; KR20180117235A

Abstract

The invention relates to a powder supply device for manufacturing a 3D shape, which comprises a processing head, a speed detection part and a control part. The machining head has: a laser irradiation section for irradiating a laser beam to melt the powder supplied to the molten pool; and a powder injection part arranged outside the laser irradiation part and used for injecting powder to be supplied to the molten pool. The speed detection unit detects a moving speed of the machining head along the machining path. The control unit receives the movement speed data of the processing head from the speed detection unit, and raises the processing head or the powder injection unit to reduce the amount of powder supplied to the molten pool when the movement speed of the processing head is reduced.

Description

Powder supply device for 3D shape manufacturing

Technical Field

The present invention relates to a powder supply device (Apparatus for supplying powder for manufacturing three dimensional shapes) for manufacturing a 3D shape, and more particularly, to a powder supply device for manufacturing a 3D shape by repeating an operation of supplying powder to a molten pool and irradiating a laser beam to weld the powder to form a powder layer, thereby manufacturing a 3D shape.

Background

Generally, 3D printing is a device that slices CAD data of a product to be manufactured in one direction on a computer, and sequentially prints and laminates two-dimensional sectional shapes after slicing to manufacture a 3D shape.

3D prints sample preparation before mainly used new product launch market to detect and correct what has had the problem in the actual product, recently, along with 3D prints the development of process and material attribute, the durability and the size precision of the product that 3D printed and made obtain improving, its application field enlarges gradually.

3D printing can be divided into: a method of performing lamination by selectively pressing a material through a nozzle or orifice; a method of stacking by dropping material ink by an ink jet head; a method of laminating by irradiating ultraviolet light or a laser beam to the liquid resin or the applied powder material to harden or weld the resin; a method of selectively spraying a liquid adhesive onto a powder material by an ink jet head to laminate the powder material; a method of supplying powder to a molten pool obtained by focusing a laser beam or an electron beam on the surface of a base portion to laminate a powder layer, and the like.

Fig. 1 is a diagram illustrating a conventional method of forming a powder layer with a processing head in a method of forming a powder layer 1 by welding a supplied powder P by irradiating a laser beam L.

Referring to fig. 1, a processing head 10 is constituted by a laser irradiation portion 11 and a powder ejection portion 12, the laser irradiation portion 11 being for irradiating a laser beam L for melting a powder P supplied to a molten pool 3 formed on a base portion 2; the powder injection portion 12 is used to inject the powder P to be supplied to the molten pool 3.

The powder layer 1 is formed into a 3D shape by repeating an operation of ejecting the powder P to the molten pool 3 formed on the base portion 2 while moving the machining head 10 in one direction, and irradiating the laser beam L from the machining head 10 to melt and solidify the powder layer 1, thereby laminating a plurality of layers of the powder layer 1.

However, conventionally, in the process of moving the machining head 10 along the machining path, the same amount of the powder P is supplied to the molten pool 3 regardless of the moving speed of the machining head 10, and therefore the height of the powder layer 1 is locally different, which causes a problem that the surface of the powder layer 1 is uneven.

For example, if the machining path is constituted by a combination of a straight portion and a corner portion, the moving speed of the machining head 10d at the straight portion is relatively high, and the moving speed at the corner portion is relatively low. As described above, if the powder P is supplied equally to the position S1 where the movement speed of the processing head 10 is high and the position S2 where the movement speed of the processing head 10 is low, the amount of the powder P stacked at the position S2 where the movement speed of the processing head 10 is low increases, and the height of the powder layer 1 at the corresponding position becomes relatively high.

In order to form a 3D shape, it is necessary to stack a plurality of powder layers 1, but if the height deviation of the powder layers 1 is continuously and repeatedly accumulated at the same position, the size of the finally produced product is poor.

In addition, when the height of a part of the already-laminated powder layer 1 is formed relatively high, if the same amount of powder P is continuously supplied, the height is formed relatively high at a corresponding portion of the finally-produced product, resulting in a product having a poor size.

Disclosure of Invention

An aspect of the present invention provides a powder supplying apparatus for 3D shape manufacturing, which can uniformly form a surface of a powder layer and can improve dimensional accuracy of a finally manufactured product by controlling an amount of powder supplied to a melt pool by receiving a moving speed of a processing head for spraying powder or height data of the powder layer.

The powder supply device for 3D shape manufacturing according to an embodiment of the present invention includes: a processing head having a laser irradiation portion for irradiating a laser beam to melt a powder supplied to a molten pool and a powder injection portion provided outside the laser irradiation portion for injecting the powder to be supplied to the molten pool; a speed detection unit that detects a moving speed of the machining head along a machining path; and a control unit that receives the movement speed data of the machining head from the speed detection unit, and that, when the movement speed of the machining head is decreased, raises the machining head or the powder injection unit to decrease the amount of powder supplied to the molten pool.

The laser beam is irradiated to the powder through a center portion of the processing head to form the molten pool, the powder is obliquely ejected toward the molten pool around the laser beam, and a powder convergence point at which the powder converges is located at a position higher than a surface of the molten pool when an amount of the powder supplied to the molten pool is to be reduced.

The laser irradiation unit and the powder injection unit are provided so as to be capable of relative movement in the vertical direction; when the movement speed of the processing head is reduced, the control unit raises the powder injection unit with respect to the laser irradiation unit to reduce the amount of powder supplied to the molten pool.

The laser irradiation part and the powder injection part are integrally formed; when the movement speed of the machining head is reduced, the control unit raises the laser irradiation unit and the powder injection unit together to reduce the amount of powder supplied to the molten pool.

A powder supplying device for 3D shape manufacturing according to another embodiment of the present invention includes: a processing head having a laser irradiation portion for irradiating a laser beam to melt a powder supplied to a molten pool and a powder injection portion provided outside the laser irradiation portion for injecting the powder to be supplied to the molten pool; a height detection unit that detects a height of the base portion or a height of a powder layer formed by the powder deposition along a processing path; and a control unit that receives data on the height of the base portion or the height of the powder layer from the height detection unit, and that, when the height of the base portion or the height of the powder layer increases, raises the machining head or the powder injection unit to reduce the amount of powder supplied to the molten pool.

The laser beam is irradiated to the powder through a center portion of the processing head to form the melt pool, the powder being ejected obliquely toward the melt pool around the laser beam; when the amount of powder supplied to the molten pool is to be reduced, a powder convergence point at which the powder converges is located at a position higher than the surface of the molten pool.

The laser irradiation unit and the powder injection unit are provided so as to be capable of relative movement in the vertical direction; when the height of the base portion or the height of the powder layer increases, the control portion raises the powder ejection portion with respect to the laser irradiation portion, thereby reducing the amount of powder supplied to the melt pool.

The laser irradiation part and the powder injection part are integrally formed; when the height of the base portion or the height of the powder layer increases, the control portion raises the laser irradiation portion and the powder ejection portion together to decrease the amount of powder supplied to the melt pool.

The powder supplying device for 3D shape manufacturing according to an embodiment of the present invention can uniformly form the surface of the powder layer and can improve the dimensional accuracy of the finally manufactured product.

In addition, the height of the powder layer can be controlled in real time.

Drawings

Fig. 1 is a diagram illustrating a conventional method of forming a powder layer using a processing head.

Fig. 2 is a view schematically showing a powder supplying apparatus for 3D shape manufacturing according to an embodiment of the present invention.

Fig. 3 is a diagram illustrating the principle of the powder supply device for manufacturing a 3D shape of fig. 2.

Fig. 4 is a diagram for explaining an operation state of a machining head of the powder supply device for 3D shape manufacturing of fig. 2.

Fig. 5 is a diagram for explaining an operation state of a modification of the machining head of the powder supply device for 3D shape manufacturing of fig. 2.

Fig. 6 is a view schematically showing a powder supplying apparatus for 3D shape manufacturing according to another embodiment of the present invention.

Fig. 7 is a diagram illustrating the principle of the powder supply device for manufacturing a 3D shape of fig. 6.

Description of the reference numerals

100: powder supply device for 3D shape manufacturing

110: machining head

111: laser irradiation unit

112: powder injection part

120: speed detection unit

130: control unit

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the embodiments. The present invention may be embodied in various forms, but is not limited to the embodiments described herein.

In order to clearly explain the present invention, portions that are not related to the description are omitted in the drawings, and the same reference numerals are used for the same or similar components throughout the specification.

Throughout the specification, "connected" of a certain portion to another portion includes a case of "directly connected" and a case of "indirectly connected" through another member. Note that unless otherwise specified, a part "including" a certain component means that other components may be included without excluding other components.

Hereinafter, an embodiment of the powder supplying device for 3D shape manufacturing according to the present invention will be described in detail with reference to the drawings.

Referring to fig. 2, the powder supply device 100 for manufacturing a 3D shape according to the present embodiment is configured to repeatedly perform an operation of supplying powder to a molten pool and irradiating laser beam to deposit the powder to form a powder layer, and the powder supply device 100 includes a processing head 110, a speed detection unit 120, and a control unit 130 to manufacture a 3D shape.

The processing head 110 is for irradiating a laser beam L and spraying a powder P, and includes a laser irradiation section 111 and a powder spraying section 112.

The laser irradiation unit 111 irradiates a laser beam L to melt the powder P supplied to the molten pool 3. The laser irradiation unit 111 is provided at the center of the processing head 110, and may include a condenser lens (not shown) therein for focusing the laser beam L output and transmitted from a laser output unit (not shown).

The powder injection part 112 is provided outside the laser irradiation part 111, and injects the powder P to be supplied to the molten pool 3. The powder P supplied from a powder supply device (not shown) provided separately outside is ejected to the molten pool 3 through the nozzle 112a of the powder ejection portion 112. The laser beam L irradiates the powder P supplied on the molten pool 3, and the powder P is deposited by the thermal energy of the irradiated laser beam L to form the powder layer 1.

The nozzle 112a of the powder injection part may be formed as a plurality of injection holes arranged at a predetermined angle along the periphery of the laser irradiation part 111, or may be formed as a ring-shaped injection hole around the periphery of the laser irradiation part 111.

The speed detection unit 120 detects the moving speed of the machining head 110 along the machining path.

The machining path in this specification refers to a path in which the machining head 110 is moved to laminate the powder layer 1 formed in accordance with the shape of the product to be finally produced while the laser beam L is irradiated and the powder P is ejected.

As described above, the processing head 110 does not move at the same moving speed over the entire processing path. For example, when the processing path is constituted by a combination of a straight portion and a corner portion, generally, the moving speed of the processing head 110 is relatively high on the straight portion, and the moving speed of the processing head 110 is relatively low on the corner portion.

While the machining head 110 is moving along the machining path, the speed detection unit 120 detects the moving speed of the machining head 110 on the machining path in real time, and transmits the detected moving speed data to the control unit 130 described later.

The control unit 130 receives the movement speed data of the processing head 110 from the speed detection unit 120, and reduces the amount of the powder P supplied to the molten pool 3 when the movement speed of the processing head 110 is reduced.

If the powder P is supplied equally to the position S1 where the movement speed of the processing head 110 is high and the position S2 where the movement speed of the processing head 110 is low, the amount of the powder P supplied to the molten pool 3 becomes large at the position S2 where the movement speed of the processing head 110 is low, resulting in a relatively high height of the powder layer 1 at the corresponding position.

Therefore, in the present invention, the amount of the powder P supplied to the molten pool 3 at the position where the moving speed of the processing head 110 is slow is reduced compared to the amount of the powder P supplied to the molten pool 3 at the position S1 where the moving speed of the processing head 110 is fast, and the height of the powder layer 1 can be formed uniformly over the entire processing path.

The present invention is characterized in that when the moving speed of the machining head 110 is reduced, the machining head 110 or the powder injection part 112 is raised to reduce the amount of the powder P supplied to the molten pool 3.

As a method of reducing the amount of the powder P supplied to the molten pool 3 at the position S2 where the moving speed of the machining head 110 is slow, a method of controlling the amount of the powder P supplied to the powder ejection part 112 from a powder supply device (not shown) separately provided outside may be considered.

However, when this method is used, a delay occurs between the timing of detecting the moving speed of the processing head 110 in real time and the timing of controlling the powder supply device provided on the outside so that the powder injection unit 112 injects the controlled amount of the powder P, and the reduced amount of the powder P is not injected at the position S2 where the moving speed of the processing head 110 is slow, but the reduced amount of the powder P is injected at another position after the position where the reduced amount of the powder P is to be injected is passed.

Therefore, in order to correlate the movement speed of the machining head 110 and the amount of the powder P supplied to the molten pool 3 in real time, it is preferable to detect the movement speed of the machining head 110, directly raise the machining head 110 or the powder ejection part 112 at the position S2 where the movement speed of the machining head 110 is low, and reduce the amount of the powder P supplied to the molten pool 3.

Referring to fig. 3, a laser beam L is irradiated to a powder P through a central portion of a processing head 110 to form a molten pool 3, and the powder P is obliquely ejected toward the molten pool 3 around the laser beam L to form a powder layer 1 on a base portion 2.

As shown in fig. 3(a), at a position S1 where the movement speed of the processing head 110 is high, the focal point LF of the laser beam and the powder convergence point PC at which the powder P injected by the powder injection part 112 converges converge on the molten pool 3. Since the powder P is ejected obliquely toward the lower side around the laser beam L, the powder convergence point PC at which the powder P converges indicates a position at which the supply amount of the powder P is relatively large. In this state, the amount of the powder P supplied to the molten pool 3 is relatively large.

As shown in fig. 3(b), at a position S2 where the movement speed of the machining head 110 is slow, the machining head 110 or the powder injection part 112 is raised, and the powder convergence point PC at which the powder P converges is located at a position higher than the surface of the molten pool 3. Since the powder P ejected from the powder ejection portion 112 converges at the powder convergence point PC and then disperses below the powder convergence point PC, the amount of the powder P actually entering the molten pool 3 is relatively small even if the amount of the powder P ejected from the powder ejection portion 112 is the same.

Accordingly, by adjusting the position of the powder converging point PC, the amount of the powder P supplied to the molten pool 3 is relatively large at the position S1 where the moving speed of the processing head 110 is high, and the amount of the powder P supplied to the molten pool 3 is relatively small at the position S2 where the moving speed of the processing head 110 is low, so that the height of the powder layer 1 formed along the processing path is maintained uniform as a whole.

After that, if the moving speed of the processing head 110 is increased again, it is of course possible to increase the amount of the powder P supplied to the molten pool 3 by lowering the processing head 110 or the powder injection part 112.

The processing head of the powder supply device for 3D shape production according to the present embodiment may be configured as follows.

Referring to fig. 4, the laser irradiation unit 111 and the powder injection unit 112 constituting the processing head 110 are provided so as to be movable relative to each other in the vertical direction.

At a position S1 where the movement speed of the machining head 110 is high, the laser irradiation part 111 and the powder injection part 112 are arranged at the same height, and the amount of the powder P supplied to the molten pool 3 is relatively increased as the powder convergence point PC converges on the molten pool 3. At a position S2 where the movement speed of the machining head 110 is slow, the powder ejection part 112 is raised relative to the laser irradiation part 111 so that the powder convergence point PC is located at a position higher than the surface of the molten pool 3, and the amount of the powder P supplied to the molten pool 3 is relatively small.

The structure for moving the powder spray part 112 up and down with respect to the laser irradiation part 111 may be implemented by providing a linear motion unit between the laser irradiation part 111 and the powder spray part 112, and a detailed description thereof will be omitted since the structure of such a linear motion unit is generally known to those skilled in the art.

On the other hand, the machining head 110 may be configured as shown in fig. 5. Fig. 5 is a diagram for explaining an operation state of a modification of the machining head of the powder supply device for 3D shape manufacturing of fig. 2.

Referring to fig. 5, the laser irradiation part 111 ' and the powder injection part 112 ' constituting the processing head 110 ' may be integrally formed.

At the position S1 where the movement speed of the machining head 110 ' is high, the laser irradiation part 111 ' and the powder ejection part 112 ' are located at the same height, and the amount of the powder P supplied to the molten pool 3 is relatively increased as the powder convergence point PC converges on the molten pool 3. At a position S2 where the movement speed of the machining head 110 ' is slow, the laser irradiation part 111 ' is raised together with the powder ejection part 112 ', the powder convergence point PC is located at a position higher than the surface of the molten pool 3, and the amount of the powder P supplied to the molten pool 3 is relatively reduced.

The focal point LF of the laser beam L has a focal depth (depth of focus) of a prescribed length. Therefore, even if the laser irradiation portion 111 'rises together with the powder injection portion 112' as described above, the rise height is within the focal depth range, and therefore the intensity (intensity) of the laser beam L irradiated to the molten pool 3 can be constantly maintained.

The structure for moving up and down the laser irradiation unit 111 ' together with the powder injection unit 112 ' can be realized by providing a linear motion unit in the processing head 110 ', and a detailed description thereof will be omitted since the structure of the linear motion unit is generally known to those skilled in the art.

On the other hand, fig. 6 is a view schematically showing a powder supply device for 3D shape manufacturing according to another embodiment of the present invention, and fig. 7 is a view for explaining the principle of the powder supply device for 3D shape manufacturing of fig. 6.

Referring to fig. 6 and 7, the powder supply device 200 for 3D shape manufacturing according to the present embodiment includes a processing head 210, a speed detection unit 220, and a control unit 230.

The processing head 210 is a member for irradiating the laser beam L and spraying the powder P, and has a laser irradiation section 211 and a powder spraying section 212.

The laser irradiation portion 211 irradiates the laser beam L output-transmitted from the laser output portion 201 to melt the powder P supplied to the molten pool 3, and the powder injection portion 212 is provided outside the laser irradiation portion 211 to inject the powder P to be supplied to the molten pool 3.

The processing head 210 of the present embodiment is substantially the same in function as the processing head 110 of the embodiment shown in fig. 2, and therefore, redundant description is omitted.

The height detection unit 220 detects the height of the base portion 2 or the height of the powder layer 1 formed by powder deposition along the processing path.

During the movement of the processing head 210 along the processing path, the height of the base portion 2 or the height of the powder layer 1 may not be formed uniformly over the entire processing path. Although the powder layer 1 is formed at a desired height H1 at some positions of the processing path, the height H2 of the powder layer is formed relatively high at other positions due to errors in processing conditions and the like.

While the machining head 210 is moving along the machining path, the height detection unit 220 detects the height of the base portion 2 or the height of the powder layer 1 on the machining path in real time, and transmits the detected height data to the control unit 230 described later.

The control unit 230 receives the height data of the base portion 2 or the height data of the powder layer 1 from the height detection unit 220, and decreases the amount of the powder P supplied to the molten pool 3 when the height of the base portion 2 or the height of the powder layer 1 increases.

If the powder P is equally supplied to the normal height position H1 and the high height position H2 of the powder layer 1, the powder layer 1 of the same thickness is continuously laminated, so that the portion of the high height position H2 of the powder layer 1 in the finally produced product is formed to protrude from other portions.

Therefore, in the present invention, the amount of the powder P supplied to the molten pool 3 at the position H2 where the height of the powder layer 1 is high is reduced as compared with the amount of the powder P supplied to the molten pool 3 at the position H1 where the height of the powder layer 1 is normal, and the height of the powder layer 1 can be formed uniformly over the entire processing path.

The present invention is characterized in that when the height of the base portion 2 or the height of the powder layer 1 increases, the processing head 210 or the powder injection portion 212 is raised to decrease the amount of the powder P supplied to the molten pool 3.

In order to correlate the height of the base portion 2 or the height of the powder layer 1 with the amount of the powder P supplied to the molten pool 3 in real time, the height of the base portion 2 or the height of the powder layer 1 is detected, and the processing head 210 or the powder ejecting portion 212 is directly raised at a position H2 where the height of the base portion 2 or the height of the powder layer 1 is high, thereby reducing the amount of the powder P supplied to the molten pool 3.

Referring to fig. 7, a laser beam L is irradiated to a powder P through a central portion of a processing head 210 to form a molten pool 3, and the powder P is obliquely ejected toward the molten pool 3 around the laser beam L to form a powder layer 1 on a base portion 2.

As shown in fig. 7(a), at a position H1 where the height of the powder layer 1 is normal, the focal point LF of the laser beam and the powder convergence point PC at which the powder P ejected by the powder ejection portion 112 converges converge on the molten pool 3. In this state, the amount of the powder P supplied to the molten pool 3 is relatively large.

As shown in fig. 7(b), at a position H2 where the height of the powder layer 1 is high, the processing head 210 or the powder injection part 212 is raised, and the powder convergence point PC at which the powder P converges is located at a position higher than the surface of the molten pool 3. In this state, the amount of the powder P supplied to the molten pool 3 is relatively small.

Accordingly, by adjusting the position of the powder convergence point PC, the amount of the powder P supplied to the molten pool 3 is relatively large at the position H1 where the height of the powder layer 1 is normal, and the amount of the powder P supplied to the molten pool 3 is relatively small at the position H2 where the height of the powder layer 1 is high, so that the height of the powder layer 1 formed along the processing path is maintained uniform as a whole.

After that, if the height of the base portion 2 or the height of the powder layer 1 decreases again, it is needless to say that the amount of the powder P supplied to the molten pool 3 may be increased by lowering the processing head 210 or the powder spraying portion 212.

The machining head 210 of the present embodiment may be configured as shown in fig. 4 and 5, and detailed description thereof is omitted.

Examples of the laser beam L arranged and focused on the molten pool 3 with the focal point LF of the laser beam are shown in fig. 3, 4, 5, and 7, but the laser beam L for irradiating the molten pool 3 may be irradiated in one of a focused state and a defocused state.

The powder supply device for 3D shape manufacturing according to the present invention configured as described above has an effect of being able to uniformly form the surface of the powder layer and improve the dimensional accuracy of the finally manufactured product by receiving the moving speed of the processing head for spraying the powder or the height data of the powder layer to control the amount of the powder supplied to the melt pool.

In addition, the powder supply device for 3D shape manufacturing according to the present invention is configured as described above, and can control the amount of powder supplied to the melt pool only by adjusting the height of the powder convergence point at which the powder converges, and therefore, has an effect of being able to control the height of the powder layer in real time.

The scope of the claims of the present invention is not limited to the above-described embodiments and modifications, and various embodiments can be implemented within the scope of the appended claims. Various modifications made by those skilled in the art without departing from the spirit of the invention claimed in the claims are within the scope of the claims of the invention.

Claims

1. A powder supplying device for manufacturing a 3D shape, comprising:

a processing head having a laser irradiation portion for irradiating a laser beam to melt a powder supplied to a molten pool and a powder injection portion provided outside the laser irradiation portion for injecting the powder to be supplied to the molten pool;

a speed detection unit that detects a moving speed of the machining head in real time along a machining path;

a control unit that receives the movement speed data of the machining head from the speed detection unit, and that, when the movement speed of the machining head decreases, directly raises the machining head or the powder injection unit to reduce the amount of powder supplied to the molten pool,

wherein the laser beam is irradiated to the powder through a central portion of the processing head to form the melt pool, the powder is ejected obliquely toward the melt pool around the laser beam, and

wherein, when the amount of powder supplied to the molten pool is to be reduced, a powder convergence point at which the powder converges is located at a position higher than a surface of the molten pool.

2. The powder supplying device for 3D shape manufacturing according to claim 1,

the laser irradiation part and the powder injection part are provided so as to be capable of relative movement in the up-down direction,

when the movement speed of the processing head is reduced, the control unit raises the powder injection unit with respect to the laser irradiation unit to reduce the amount of powder supplied to the molten pool.

3. The powder supplying device for 3D shape manufacturing according to claim 1,

the laser irradiation part and the powder injection part are integrally formed,

when the movement speed of the machining head is reduced, the control unit raises the laser irradiation unit and the powder injection unit together to reduce the amount of powder supplied to the molten pool.