CN112974854A - Electron beam additive manufacturing device and method - Google Patents
Electron beam additive manufacturing device and method Download PDFInfo
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- CN112974854A CN112974854A CN202110470366.5A CN202110470366A CN112974854A CN 112974854 A CN112974854 A CN 112974854A CN 202110470366 A CN202110470366 A CN 202110470366A CN 112974854 A CN112974854 A CN 112974854A
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- additive manufacturing
- electron beam
- negative electrode
- positive electrode
- powder bed
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- 238000010894 electron beam technology Methods 0.000 title claims abstract description 42
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 38
- 239000000654 additive Substances 0.000 title claims abstract description 37
- 230000000996 additive effect Effects 0.000 title claims abstract description 37
- 238000000034 method Methods 0.000 title abstract description 14
- 239000000843 powder Substances 0.000 claims abstract description 95
- 230000007480 spreading Effects 0.000 claims description 7
- 238000003892 spreading Methods 0.000 claims description 7
- 238000007664 blowing Methods 0.000 abstract description 12
- 230000015556 catabolic process Effects 0.000 abstract description 7
- 239000010410 layer Substances 0.000 description 6
- 150000002500 ions Chemical class 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 239000001307 helium Substances 0.000 description 4
- 229910052734 helium Inorganic materials 0.000 description 4
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 238000005245 sintering Methods 0.000 description 4
- 230000005684 electric field Effects 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- 238000009825 accumulation Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y10/00—Processes of additive manufacturing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y30/00—Apparatus for additive manufacturing; Details thereof or accessories therefor
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
Abstract
The invention belongs to the technical field of additive manufacturing, and discloses an electron beam additive manufacturing device and method, wherein the electron beam additive manufacturing method comprises the following steps: and arranging a positive electrode and a negative electrode on two opposite sides of the grounded forming cylinder, and applying instantaneous high voltage to the positive electrode and the negative electrode before additive manufacturing so as to electrically break down the powder bed on the forming cylinder and enable the powder bed to be electrically conducted in the horizontal direction. After the powder is paved, the instantaneous high voltage is applied to the two sides of the powder bed to electrically breakdown the powder bed, the powder bed after the electric breakdown is in an electric conduction state along the horizontal direction, and the powder bed is in a grounding state, so that the electric charge on the powder after the electron beam scanning is conducted to the ground, and the phenomenon of powder blowing is effectively avoided.
Description
Technical Field
The invention relates to the technical field of additive manufacturing, in particular to an electron beam additive manufacturing device and method.
Background
The technical principle of the electron beam powder laying additive manufacturing is as follows: and under a vacuum environment, scanning and melting the powder layers by the electron beams, so that a plurality of continuous powder layers are fused together to manufacture the three-dimensional solid part. In the additive manufacturing process, because the metal powder material has poor conductivity, charges are easy to accumulate under the action of electron beams, and charged metal powder particles repel each other to generate a powder blowing phenomenon. The "blowing" will break the already laid-flat powder layer, resulting in a failure of the additive manufacturing process.
The existing solution is to preheat the powder bed by using electron beams, that is, to pass through a specific scanning path, so that the temperature of the powder is raised, after the temperature is raised, micro-sintering is generated among powder particles, and the electrical conductivity is increased, thereby further avoiding powder blowing, and the method is a 'hot powder bed' process. However, the sintered powder causes difficulty in powder removal. In particular, when the manufactured part contains a complicated inner flow passage or cavity, the sintered powder of the inner flow passage or cavity is difficult to remove. Also, each layer needs to be preheated, which reduces the efficiency of additive manufacturing.
In addition to the above method, charge accumulation can be avoided by adding a positive ion source in addition to the electron beam, wherein the positive ion source covers the shaping area, and the positive ions and the incident electrons are neutralized. The benefits of this are: the powder layer does not need to be preheated, the process is a 'cold powder bed' process, the powder cannot be sintered, and loose powder can easily flow out of the inner flow passage or the inner cavity and be removed. Meanwhile, a preheating step is omitted, and the additive manufacturing efficiency is improved. However, this method requires the use of helium gas to generate positive ions, and requires the consumption of helium gas, which is costly.
Therefore, there is a need for an additive manufacturing apparatus and method that can effectively suppress "powder blowing" at low cost to solve the above problems.
Disclosure of Invention
The invention aims to provide an electron beam additive manufacturing device and method, which can effectively avoid the problem of powder blowing and have low cost.
In order to achieve the purpose, the invention adopts the following technical scheme:
an electron beam additive manufacturing method is characterized in that a positive electrode and a negative electrode are arranged on two opposite sides of a grounded forming cylinder, and instantaneous high voltage is applied to the positive electrode and the negative electrode before additive manufacturing so as to electrically break down a powder bed on the forming cylinder and enable the powder bed to be electrically conducted in a horizontal direction.
Preferably, a momentary high voltage is applied to the positive electrode and the negative electrode after the powder spreading is completed and before the electron beam scans the powder bed.
Preferably, the transient high pressure is 5000-.
The invention also provides an electron beam additive manufacturing device, which comprises a grounded forming cylinder, wherein the forming cylinder comprises a first side and a second side which are oppositely arranged, the first side is provided with a positive electrode, the second side is provided with a negative electrode, a high-voltage applying source is connected between the positive electrode and the negative electrode, and the high-voltage applying source is configured to apply instantaneous high voltage to the positive electrode and the negative electrode so as to electrically break down a powder bed on the forming cylinder and enable the powder bed to be electrically conducted in the horizontal direction.
Preferably, the positive electrode and the negative electrode are respectively disposed on both left and right sides of the forming cylinder.
Preferably, the positive electrode and the negative electrode are respectively disposed on front and rear sides of the forming cylinder.
Preferably, the positive electrode and the negative electrode are disposed on both sides of the forming cylinder in a horizontal state.
Preferably, one end of the positive electrode and the negative electrode is disposed through the forming cylinder and in contact with the powder bed.
Preferably, the electron beam additive manufacturing apparatus further comprises a molding chamber through which the cables to which the positive electrode and the negative electrode are connected are arranged in an insulated and sealed manner.
Preferably, the cables for connecting the positive electrode and the negative electrode are arranged on the same side of the forming chamber in a penetrating mode.
The invention has the beneficial effects that: after the powder is paved, an instantaneous high voltage is applied to two sides of the powder bed to electrically breakdown the powder bed, the powder bed after the electrical breakdown is in an electrically conducting state along the horizontal direction, and the powder bed is in a grounding state, so that the electric charges on the powder after the electron beam scanning are conducted to the ground, and the phenomenon of powder blowing is effectively avoided. Compared with a mode of inhibiting powder blowing in the prior art, on one hand, scanning preheating micro-sintering is not needed to be carried out on the powder bed, so that powder is not difficult to remove, scanning preheating micro-sintering is not carried out on the powder bed, the time of single-layer powder forming is shortened, and the additive manufacturing efficiency is improved; on the other hand, helium does not need to be consumed, and the cost is lower.
Drawings
Fig. 1 is a schematic structural diagram of an electron beam additive manufacturing apparatus provided in the present invention.
In the figure:
1. a forming cylinder; 2. a positive electrode; 3. a negative electrode; 4. a forming chamber; 5. a hopper; 6. a powder spreading device; 7. an electron beam generating device; 8. a powder bed.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
In the description of the present embodiment, the terms "upper", "lower", "right", etc. are used in an orientation or positional relationship based on that shown in the drawings only for convenience of description and simplicity of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.
The invention provides an electron beam additive manufacturing device which can inhibit the powder blowing phenomenon and avoid the powder blowing phenomenon on the basis of not preheating and micro-sintering a powder bed 8. Compared with a mode of generating neutralization through positive ions and incident electrons and avoiding charge accumulation, the electron beam additive manufacturing device disclosed by the invention consumes less helium and is lower in cost.
As shown in fig. 1, the electron beam additive manufacturing apparatus includes a forming cylinder 1, the forming cylinder 1 is located in a forming chamber 4 having a vacuum environment, a hopper 5, a powder spreading device 6, and an electron beam generating device 7 are respectively disposed in the forming chamber 4, metal powder in the hopper 5 is spread on the forming cylinder 1 by the powder spreading device 6 to form a powder bed 8, and then the powder bed 8 is scanned and melted by an electron beam emitted by the electron generating device, and a desired three-dimensional part is finally processed by layer-by-layer processing.
In this embodiment, the forming cylinder 1 is grounded, and the grounding manner may be that the forming cylinder 1 is connected to a ground wire, or the forming chamber 4 is connected to a ground wire, at this time, since the forming cylinder 1 and the forming chamber 4 are in a connected state and both are made of metal materials, the forming cylinder 1 is also in a grounded state. It should be noted that when the forming cylinder 1 is grounded, the powder bed 8 laid in the forming cylinder 1 by the powder laying device 6 is also grounded.
The forming cylinder 1 comprises a first side and a second side which are oppositely arranged, wherein the first side is provided with a positive electrode 2, the second side is provided with a negative electrode 3, a high voltage applying source (not shown in the figure) is connected between the positive electrode 2 and the negative electrode 3, instantaneous high voltage can be applied to the positive electrode 2 and the negative electrode 3 through the high voltage applying source, and then the instantaneous high voltage is applied to the powder bed 8 of the forming cylinder 1 through the positive electrode 2 and the negative electrode 3, because the instantaneous high voltage has a large value, the powder bed 8 can be electrically broken down (dielectric properties of a medium, such as insulation and dielectric capacity, refer to the insulation properties of materials in a certain electric field strength range, the medium can only keep the properties within a certain electric field strength, when the electric field strength exceeds a certain critical value, the medium is changed from a dielectric state to a conductive state, and the phenomenon is called, also called electrical breakdown) to place the powder bed 8 in an electrically conductive state. When the powder bed 8 is in a conductive state by electric breakdown, in the process that the powder bed 8 is scanned and melted by the electron beams emitted by the electron beam generating device 7, the charges on the powder of the powder bed 8 can circulate along the conducting direction and are finally guided into the ground through the forming cylinder 1, at the moment, the charges are not accumulated on the powder bed 8 any more, mutual repulsion of the metal powder due to the charges does not exist, and the phenomenon of powder blowing is avoided.
In the present embodiment, the above-described positive electrode 2 and negative electrode 3 are respectively provided on the left and right sides of the molding cylinder 1, and when a high voltage is applied instantaneously by the high voltage application source, the powder bed 8 is electrically broken down and electrically conducted in the horizontal direction. Due to the anisotropic conductivity of the electrically broken-down powder bed 8, it is only electrically conductive in the horizontal direction, but not in the vertical direction. Preferably, the positive electrode 2 and the negative electrode 3 are horizontally disposed on both sides of the forming cylinder 1, further ensuring that the powder bed 8 is electrically conducted in the horizontal direction after electrical breakdown.
It will be appreciated that the positive electrode 2 and the negative electrode 3 may be disposed on the front and rear sides of the forming cylinder 1, respectively, and the powder bed 8 is electrically broken down and then electrically conducted in the horizontal direction.
As a preferred solution, one end of the above-mentioned positive electrode 2 and negative electrode 3 is disposed through the forming cylinder 1 and in contact with the powder bed 8 to ensure that a momentary high voltage can be applied to the powder bed 8 of the forming cylinder 1 through the positive electrode 2 and negative electrode 3 to electrically break down the powder bed 8.
In this embodiment, the above-mentioned instantaneous high pressure is required to be large, preferably 8000V 5000-.
In the present embodiment, the cables to which the positive electrodes 2 and the negative electrodes 3 are connected are arranged through the molding chamber 4 in an insulated and sealed manner to achieve connection with a high voltage application source. Preferably, the cables for connecting the positive electrode 2 and the negative electrode 3 are threaded through the same side of the forming chamber 4, so that the connection with the high voltage application source is more convenient.
The embodiment also provides an electron beam additive manufacturing method, which can be realized by the electron beam additive manufacturing device, specifically, after the powder spreading is completed by the powder spreading device 6 and just before the electron beam generated by the electron beam generating device 7 scans the powder bed 8, instantaneous high pressure is applied to the positive electrode 2 and the negative electrode 3 by the high-voltage applying source, at this time, the instantaneous high pressure is applied to the powder bed 8 of the forming cylinder 1 through the positive electrode 2 and the negative electrode 3 so as to electrically break down the powder bed 8 on the forming cylinder 1, so that the powder bed 8 is electrically conducted in the horizontal direction, and then the electron beam can scan and melt the powder bed 8, in the process, electric charges generated by the powder bed 8 can be guided to the ground through the powder bed 8 and the forming cylinder 1, so as to avoid the occurrence of the phenomenon of powder blowing.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Numerous obvious variations, adaptations and substitutions will occur to those skilled in the art without departing from the scope of the invention. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.
Claims (10)
1. An electron beam additive manufacturing method is characterized in that a positive electrode (2) and a negative electrode (3) are arranged on two opposite sides of a grounded forming cylinder (1), and instantaneous high voltage is applied to the positive electrode (2) and the negative electrode (3) before additive manufacturing so as to electrically break down a powder bed on the forming cylinder (1) and enable the powder bed to be electrically conducted in the horizontal direction.
2. The electron beam additive manufacturing method according to claim 1, wherein a momentary high voltage is applied to the positive electrode (2) and the negative electrode (3) after powder spreading is completed and before an electron beam scans the powder bed.
3. The electron beam additive manufacturing method according to claim 1, wherein the instantaneous high voltage is 8000V of 5000-.
4. An electron beam additive manufacturing device, characterized by comprising a grounded forming cylinder (1), wherein the forming cylinder (1) comprises a first side and a second side which are oppositely arranged, the first side is provided with a positive electrode (2), the second side is provided with a negative electrode (3), a high voltage applying source is connected between the positive electrode (2) and the negative electrode (3), and the high voltage applying source is configured to apply instantaneous high voltage to the positive electrode (2) and the negative electrode (3) so as to electrically break down a powder bed on the forming cylinder (1) and enable the powder bed to be electrically conducted along the horizontal direction.
5. The electron beam additive manufacturing apparatus according to claim 4, wherein the positive electrode (2) and the negative electrode (3) are respectively provided on left and right sides of the forming cylinder (1).
6. The electron beam additive manufacturing apparatus according to claim 5, wherein the positive electrode (2) and the negative electrode (3) are respectively provided on front and rear sides of the forming cylinder (1).
7. The electron beam additive manufacturing apparatus according to claim 5 or 6, wherein the positive electrode (2) and the negative electrode (3) are disposed on both sides of the forming cylinder (1) in a horizontal state.
8. The electron beam additive manufacturing device according to claim 5, wherein one end of the positive electrode (2) and the negative electrode (3) is arranged through the forming cylinder (1) and in contact with the powder bed.
9. The electron beam additive manufacturing device according to claim 8, further comprising a forming chamber (4), wherein a cable to which the positive electrode (2) and the negative electrode (3) are connected is arranged through the forming chamber (4) in an insulated and sealed manner.
10. The electron beam additive manufacturing device according to claim 9, wherein cables connecting the positive electrode (2) and the negative electrode (3) are threaded through the same side of the forming chamber (4).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110470366.5A CN112974854A (en) | 2021-04-28 | 2021-04-28 | Electron beam additive manufacturing device and method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110470366.5A CN112974854A (en) | 2021-04-28 | 2021-04-28 | Electron beam additive manufacturing device and method |
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| CN112974854A true CN112974854A (en) | 2021-06-18 |
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| CN202110470366.5A Pending CN112974854A (en) | 2021-04-28 | 2021-04-28 | Electron beam additive manufacturing device and method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115401217A (en) * | 2022-10-10 | 2022-11-29 | 航发优材(镇江)增材制造有限公司 | Electron beam selective powder bed preheating process parameter development method |
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2021
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115401217A (en) * | 2022-10-10 | 2022-11-29 | 航发优材(镇江)增材制造有限公司 | Electron beam selective powder bed preheating process parameter development method |
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Application publication date: 20210618 |