Additive manufacturing apparatus

Abstract

An additive manufacturing apparatus (1). The additive manufacturing equipment (1) comprises a forming bin (10) with variable volume; the powder laying device (20) is used for laying metal powder in the forming bin (10) in the additive manufacturing stage; the high-energy beam generating device (30) is used for generating a high-energy beam in an additive manufacturing stage so as to process metal powder; the gas washing device (40) is used for carrying out gas washing operation on the forming bin (10) in the gas washing stage; wherein the forming bin (10) has a first volume corresponding to the additive manufacturing stage and a second volume corresponding to the gas washing stage, and the first volume is larger than the second volume. The additive manufacturing equipment (1) can shorten the gas washing time and improve the equipment utilization rate.

Description

Technical Field

[0001] The present disclosure relates to the technical field of additive manufacturing, and in particular to an additive manufacturing device. Background Art

[0002] Additive manufacturing technology (or 3D printing technology) can use high-energy beams to process powder materials to print out three-dimensional components of specified shapes. After printing a component and before printing the next component, it is usually necessary to take the component out of the molding chamber and use a gas washing device to wash the molding chamber. The relevant technology takes a long time in the gas washing stage, resulting in low equipment utilization. Summary of the invention

[0003] The embodiment of the present application provides an additive manufacturing device to reduce the gas washing time and improve the utilization rate of the equipment.

[0004] The additive manufacturing equipment provided in the embodiment of the present application includes: a molding chamber with a variable volume; a powder spreading device, used to spread metal powder in the molding chamber during the additive manufacturing stage; a high-energy beam generating device, used to generate a high-energy beam during the additive manufacturing stage to process the metal powder; a scrubbing device, used to perform scrubbing operations on the molding chamber during the scrubbing stage; wherein the molding chamber has a first volume corresponding to the additive manufacturing stage and a second volume corresponding to the scrubbing stage, and the first volume is larger than the second volume.

[0005] As a possible implementation manner, the molding bin includes a first wall portion and a second wall portion that are arranged opposite to each other, and the first wall portion and the second wall portion can move relatively to change the volume of the molding bin.

[0006] As a possible implementation, the molding bin includes: a top wall; and a bottom plate, which is arranged opposite to the top wall; wherein the first wall portion and the second wall portion are side walls arranged between the top wall and the bottom plate.

[0007] As a possible implementation method, the additive manufacturing equipment also includes: a retractable device, which is arranged inside the molding chamber, and the volume of the retractable device has a contracted state and an enlarged state. In the additive manufacturing stage, the volume of the retractable device is in a contracted state, and in the air washing stage, the volume of the retractable device is in an enlarged state.

[0008] As a possible implementation, the retractable device is a flexible inflatable device.

[0009] As a possible implementation, the wall of the molding chamber is provided with an air flow channel which is in fluid communication with the expandable device.

[0010] As a possible implementation, the retractable device is a retractable accordion folding component.

[0011] As a possible implementation manner, the outer wall of the retractable device is made of airtight material.

[0012] Compared with the additive manufacturing stage, the molding chamber has a smaller volume in the gas washing stage, so the gas washing time can be shortened and the utilization rate of the equipment can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of the structure of the additive manufacturing equipment provided in an embodiment of the present application.

[0014] Figure 2 A structural example diagram of a possible implementation of a variable volume molding chamber.

[0015] Figure 3 A structural example diagram of another possible implementation of a variable-volume molding chamber.

[0016] Figure 4 This is a structural example diagram of another possible implementation of a variable-volume molding bin. DETAILED DESCRIPTION

[0017] Additive manufacturing technology can also be called 3D printing technology. Compared with traditional manufacturing technology, additive manufacturing technology can produce multi-dimensional structures with complex shapes, so it is being widely studied and promoted.

[0018] There are many types of additive manufacturing technologies, such as additive manufacturing technologies based on material extrusion and additive manufacturing technologies based on metal powder and high-energy beam. Metal selective laser melting technology is a typical additive manufacturing technology based on metal powder and high-energy beam. The following takes metal selective laser melting technology as an example to briefly introduce the additive manufacturing process.

[0019] Metal selective laser melting technology uses metal powder as raw material to construct complex multi-dimensional structures. The powder material is melted by focusing a high-energy beam and solidified again to obtain a specified spatial component. The additive manufacturing process is usually carried out in a closed molding chamber. After the component is printed and formed once, the component needs to be taken out, the metal powder needs to be reloaded, and the chamber door needs to be closed to keep the molding chamber closed again. Before the next printing starts, it is often necessary to remove the air in the molding chamber to ensure that the elements that need to be controlled, such as oxygen in the molding chamber, are within a controllable range. This air removal process is also called purge. For example, inert gas can be filled into the molding chamber to place the molding chamber in an inert gas atmosphere, or the gas in the molding chamber can be extracted by a vacuum device to remove the air in the molding chamber. After the purge is completed, the additive manufacturing stage can be entered to further carry out processing processes such as powder laying and laser scanning.

[0020] In order to ensure that the gas atmosphere in the molding chamber meets the specified requirements, the purge process often needs to be repeated many times. During the purge stage, the entire equipment is in a waiting state of stopping work (stopping 3D printing or additive manufacturing) until the impurity elements that need to be controlled are in the required state, and then the equipment can be started for printing, which results in low equipment utilization.

[0021] Whether the gas atmosphere content meets the standard will directly affect the quality of the printed components. If the component quality does not meet the standard due to shortening the purge time, it will not be worth the loss. Therefore, the relevant technology generally believes that the high time consumption of the purge stage is necessary.

[0022] It is true that the quality of air washing should not be reduced in order to improve equipment utilization. However, it is possible to shorten the duration of the air washing stage while ensuring the quality of air washing. The inventors have found that the duration of the air washing stage is closely related to the volume of the molding bin. In other words, if the volume of the molding bin is small, the duration of the air washing stage is relatively short; if the volume of the molding bin is large, the duration of the air washing stage will be relatively long. The internal volume of the molding bin used in related technologies is often fixed, which is not conducive to reducing the time of the air washing stage.

[0023] In view of the above problems, the embodiment of the present application proposes a molding bin with variable volume. The embodiment of the present application is described in detail below.

[0024] Figure 1 Schematic diagram of the structure of the additive manufacturing equipment provided in the embodiment of the present application. Figure 1 As shown, the additive manufacturing device 1 includes a molding chamber 10, a powder spreading device 20, a high energy beam generating device 30 and a gas washing device 40. In addition to the above devices, the additive manufacturing device 1 may also include other devices, such as powder chambers 70a and 70b, and a molding platform 80.

[0025] The powder spreading device 20 can be used to spread metal powder in the molding bin during the additive manufacturing stage. For example, the powder spreading device 20 can use a mechanism such as a roller to spread the metal powder in the powder bin layer by layer on the molding platform 80.

[0026] The high energy beam generating device 30 can be used to generate a high energy beam. The high energy beam mentioned here can be a laser or other types of ion beams. The high energy beam generating mechanism 30 can be driven by a certain motion mechanism to aim the high energy beam at the metal powder on the forming platform 80, so that the metal powder is focused, melted, and then solidified into a shape.

[0027] The gas washing device 40 can fill the molding chamber 10 with a gas such as helium or argon, thereby discharging the air in the molding chamber 10 so that the interior of the molding chamber 10 is in an inert gas atmosphere.

[0028] Of course, in some embodiments, the air washing device 40 can also exhaust the air in the molding chamber 10 by vacuuming, so that the molding chamber is in a vacuum state.

[0029] The molding chamber 10 is a molding chamber with a variable volume. The molding chamber 10 has a first volume corresponding to the additive manufacturing stage and a second volume corresponding to the gas washing stage, and the first volume is greater than the second volume. The so-called first volume corresponding to the additive manufacturing stage refers to the first volume of the molding chamber 10 in the additive manufacturing stage (or 3D printing stage). The so-called second volume corresponding to the gas washing stage refers to the second volume of the molding chamber 10 in the gas washing stage (i.e. before 3D printing, or between two 3D printings). Since the second volume is smaller than the first volume, it is equivalent to using a small volume molding chamber 10 for gas washing in the gas washing stage, and restoring the large volume of the molding chamber for additive manufacturing in the additive manufacturing stage, which can shorten the gas washing time and improve equipment utilization.

[0030] There are many ways to achieve variable volume of the molding bin 10, which are described in detail below with reference to two embodiments.

[0031] Embodiment 1

[0032] The molding chamber 10 may include a first wall portion 12 and a second wall portion 14 that are disposed opposite to each other. The first wall portion 12 and the second wall portion 14 may move relative to each other to change the volume of the molding chamber 10.

[0033] In some implementations, the first wall portion 12 may be fixedly disposed, and the second wall portion 14 may be movable toward the first wall portion 12 .

[0034] In some implementations, the second wall portion 14 may be fixedly disposed, and the first wall portion 12 may be movable toward the second wall portion 14 .

[0035] In some implementations, the first wall portion 12 and the second wall portion 14 are both movable relative to each other.

[0036] In some implementations, such as Figure 2 As shown, the molding bin 10 may include a top wall 16 and a bottom plate 18 disposed opposite to each other. The first wall portion 12 and the second wall portion 14 mentioned above are two side walls between the top wall 16 and the bottom plate 18, respectively.

[0037] In some implementations, the first wall portion 12 and the second wall portion 14 may also be a top wall 16 and a bottom plate 18 , respectively.

[0038] Before the gas washing starts, the first wall portion 12 and the second wall portion 14 can move relative to each other to reduce the volume of the molding chamber 10 (ie, the volume of the molding chamber 10 is the second volume mentioned above). Figure 2 As shown, the first wall portion 12 can be moved to the position marked by A; the second wall portion 14 can be moved to the position marked by B. In the scrubbing stage, since the volume of the molding chamber 10 becomes smaller, the scrubbing can be completed quickly. After the scrubbing is completed, the first wall portion 12 and the second wall portion 14 can move relative to each other to restore the volume of the molding chamber 10 (that is, the volume of the molding chamber 10 is the first volume mentioned above).

[0039] The relative movement of the first wall portion 12 and the second wall portion 14 can be performed under the control of a movable device, which can be implemented by a mechanism such as a slide rail, a gear rack, etc.

[0040] Embodiment 2

[0041] The additive manufacturing equipment 1 may further include a retractable device 50. The retractable device 50 may be arranged inside the molding bin 10. The volume of the retractable device 50 has a contracted state and an enlarged state. In the additive manufacturing stage, the volume of the retractable device 50 is in a contracted state, and in the gas washing stage, the volume of the retractable device 50 is in an enlarged state. That is to say, in the gas washing stage, the volume of the retractable device 50 is in an enlarged state, thereby occupying a larger space of the molding bin 10, thereby reducing the space inside the molding bin 10 that needs gas washing. In the additive manufacturing stage, the retractable device 50 returns to the contracted state, so that the molding bin 10 can process components with a larger volume.

[0042] The outer wall of the retractable device 50 is made of airtight material, so as to be isolated from the air in the space of the molding bin 10 .

[0043] There are many ways to implement the retractable device 50. Figure 3 and Figure 4 , giving examples of two possible implementations.

[0044] like Figure 3 As shown, the retractable device 50 can be a flexible expandable device. Further, in some implementations, the wall of the molding chamber 10 is provided with an air channel 60 in fluid communication with the expandable device, so that the flexible expandable device can be inflated and deflated through the air channel 60.

[0045] Exemplarily, the air flow channel 60 can be tightly connected to the side wall of the molding bin 10, and the opening and closing of the air flow channel 60 can be controlled by a valve. The outside of the air flow channel 60 can be connected to a gas charging device (not shown in the figure). The end of the air flow channel 60 located on one side of the molding bin can be connected to the flexible expandable device, and the flexible expandable device can expand when filled with gas (note that the gas in the flexible expandable device is isolated from the space in the molding bin 10). After printing is completed, the flexible expandable device can expand when filled with gas, thereby occupying the physical space in the molding bin 10. The physical space can compress the space of the molding bin 10. At this time, washing can greatly reduce the washing time. After the washing is completed, the valve is opened, and the flexible expandable device shrinks, thereby restoring the actual space of the molding bin 10.

[0046] In some embodiments, the flexible expandable device has a maximum expansion limit. When the gas washing process is a vacuuming process, the maximum expansion limit can ensure that the expandable device does not expand infinitely due to the vacuum degree in the molding chamber, causing pollution or influence on other components in the molding chamber.

[0047] like Figure 4 As shown, the retractable device 50 can be a retractable accordion folding assembly (or a flexible folding assembly). The accordion folding assembly can be opened and closed inside the molding bin 10 under the control of a movable device. The movable device can be implemented by a mechanism such as a slide rail, a gear rack, etc.

[0048] For example, a retractable accordion folding assembly can be provided on one side of the molding chamber 10. The flexible folding assembly can be moved inside the molding chamber under the traction of the movable device. For example, during the additive manufacturing process, the movable device can compress the folding assembly to be close to one side of the molding chamber 10 (such as Figure 4 When the additive manufacturing is completed and the air needs to be washed, the mobile device can pull the folding assembly to occupy most of the space of the entire molding chamber 10 (as shown in the left figure). Figure 4As shown in the right figure in the figure, the absolute space of the molding chamber 10 is reduced, which greatly saves the washing time. When the washing is completed, the movable device pulls the folding assembly to be compressed onto the side wall of the molding chamber 10. In this example, the folding assembly is made of airtight material, which can isolate the inside and outside of the assembly to make it airtight. At the same time, the side wall of the folding assembly can be installed to connect the inside and outside of the folding assembly through a valve 70, so that the folding assembly can maintain the same internal and external air pressure during the movement and be in an unfolded state.

[0049] In some embodiments, when the gas washing process is a vacuuming process, the accordion folding component has a certain strength, and the material of the folding component will not be damaged or deformed due to the vacuum state in the molding chamber.

[0050] In some embodiments, in order to cope with the change of vacuum degree in the molding chamber during the washing process, a double-layer folding component can be provided. The folding component in the outer layer has a certain strength to ensure that the vacuum degree in the molding chamber does not change and does not deform. The inner layer material of the folding component is an airtight material. The inner layer of the airtight material can have a flexible characteristic. When the folding component is filled with gas connected to the outside world so that the folding component occupies the space in the molding chamber, the inner layer material maintains the designed shape under the action of the outer layer material. It should be understood that in the design of the folding component as a double-layer material, whether the outer layer material of the folding component is airtight becomes an optional condition.

[0051] In some embodiments, in order to maintain the pressure in the molding chamber at a safe threshold, a vacuum pump can be used to remove the air in the molding chamber during the gas washing process, and inert gas can be introduced into the molding chamber at the same time. This method can improve the efficiency of the gas washing, and at the same time ensure that a certain air pressure is maintained in the molding chamber to prevent the molding chamber from being damaged by excessively high or low pressure. The damage includes but is not limited to the pressure in the molding chamber being too low, and the external atmospheric pressure exerting excessive pressure on the molding chamber structure, causing deformation of the closed structure of the molding chamber.

[0052] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. An additive manufacturing device, characterized in that: include: A molding chamber with variable volume; A powder spreading device, used for spreading the powder to be formed in the forming bin during the additive manufacturing stage; A high energy beam generating device, used for generating a high energy beam in the additive manufacturing stage to process the powder; A scrubbing device, used for scrubbing the molding bin during the scrubbing stage; The molding chamber has a first volume corresponding to the additive manufacturing stage and a second volume corresponding to the gas washing stage, and the first volume is larger than the second volume.

2. The additive manufacturing device according to claim 1, characterized in that: The molding bin includes a first wall portion and a second wall portion that are arranged opposite to each other. The first wall portion and the second wall portion can move relatively to change the volume of the molding bin.

3. The additive manufacturing device according to claim 2, characterized in that: The molding chamber comprises: top wall; A bottom plate, arranged opposite to the top wall; Wherein, the first wall portion and the second wall portion are side walls arranged between the top wall and the bottom plate.

4. The additive manufacturing device according to claim 1, characterized in that: Also includes: A retractable device is arranged inside the molding bin, and the volume of the retractable device has a contracted state and an enlarged state. In the additive manufacturing stage, the volume of the retractable device is in a contracted state, and in the air washing stage, the volume of the retractable device is in an enlarged state.

5. The additive manufacturing device according to claim 4, characterized in that: The retractable device is a flexible expandable device.

6. The additive manufacturing device according to claim 5, characterized in that: The wall of the molding bin is provided with an air flow channel which is in fluid communication with the expandable device.

7. The additive manufacturing device according to claim 4, characterized in that: The retractable device is a retractable accordion folding component.

8. The additive manufacturing device according to claim 4, characterized in that: The outer wall of the retractable device is made of airtight material.

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