Additive manufacturing apparatus

Abstract

An additive manufacturing apparatus (1). The additive manufacturing apparatus (1) comprises: a variable-volume molding chamber (10); a powder spreading device (20), used for spreading metal powder in the molding chamber (10) in an additive manufacturing stage; a high-energy beam generating device (30), used for generating a high-energy beam in the additive manufacturing stage to process the metal powder; and a gas washing device (40), used for carrying out a gas washing operation on the molding chamber (10) in a gas washing stage, wherein 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. According to the additive manufacturing apparatus (1), the gas washing time can be shortened and the utilization rate of the apparatus can be improved.

Description

Additive manufacturing equipment 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 (or 3D printing) uses a high-energy beam to process powdered materials, creating three-dimensional components of a specified shape. After printing one component and before printing the next, the component typically needs to be removed from the build chamber and purged using a gas scrubber. This purging phase in these technologies takes a long time, resulting in low equipment utilization.

[0003] Summary of the Invention

[0004] The embodiment of the present application provides an additive manufacturing device to reduce the gas washing time and improve the utilization rate of the device.

[0005] The additive manufacturing equipment provided in the embodiment of the present application includes: a molding chamber with variable volume; a powder spreading device for spreading metal powder in the molding chamber during the additive manufacturing stage; a high-energy beam generating device for generating a high-energy beam during the additive manufacturing stage to process the metal powder; and a scrubbing device for performing 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.

[0006] As a possible implementation, the forming 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 are movable relative to each other to change the volume of the forming bin.

[0007] As a possible implementation, the forming 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.

[0008] As a possible implementation method, the additive manufacturing equipment also includes: a retractable device, which is arranged inside the forming chamber, and the volume of the retractable device has a contracted state and an expanded 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 expanded state.

[0009] As a possible implementation, the retractable device is a flexible inflatable device.

[0010] As a possible implementation, the wall of the molding chamber is provided with an air flow channel in fluid communication with the inflatable device.

[0011] As a possible implementation, the retractable device is a retractable accordion folding assembly.

[0012] As a possible implementation, the outer wall of the retractable device is made of airtight material.

[0013] Compared with the additive manufacturing stage, the molding chamber has a smaller volume in the purge stage, which can shorten the purge time and improve the utilization rate of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG1 is a schematic structural diagram of an additive manufacturing device provided in an embodiment of the present application.

[0015] FIG2 is a structural diagram illustrating a possible implementation of a variable-volume molding chamber.

[0016] FIG3 is a structural diagram illustrating another possible implementation of a variable-volume molding chamber.

[0017] FIG4 is a structural example diagram of another possible implementation of a variable-volume molding chamber. DETAILED DESCRIPTION

[0018] Additive manufacturing, also known as 3D printing, is a technology that can produce complex, multi-dimensional structures compared to traditional manufacturing techniques. Therefore, it is being widely researched and promoted.

[0019] There are many types of additive manufacturing technologies, including those based on material extrusion and those using metal powders and high-energy beams. Selective metal laser melting is a typical example of this. Below, we briefly introduce the additive manufacturing process, using selective metal laser melting as an example.

[0020] Selective metal laser melting technology uses metal powder as the raw material to construct complex multidimensional structures. The powdered material is melted by a focused high-energy beam and then solidified again to form the desired spatial component. The additive manufacturing process typically takes place in a sealed build chamber. After a component is printed, it is removed, reloaded with metal powder, and the chamber door is closed to re-enclose the build chamber. Before the next print cycle begins, the air in the build chamber must be removed to ensure that controlled elements such as oxygen remain within controllable levels. This air removal process is also known as purge. For example, the build chamber can be filled with inert gas to create an inert atmosphere, or the air inside the chamber can be extracted using a vacuum pump to remove the air. After purge is complete, the additive manufacturing phase can begin, with further processing steps such as powder application and laser scanning.

[0021] To ensure the atmosphere in the build chamber meets specified requirements, the purge process often needs to be repeated multiple times. During this purge phase, the entire machine is in a standby state (stopping 3D printing or additive manufacturing) until all impurities that require control are at the required level. This results in low equipment utilization.

[0022] 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 long purge stage is necessary.

[0023] Admittedly, 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 chamber. In other words, if the volume of the molding chamber is small, the duration of the air washing stage is relatively short; if the volume of the molding chamber is large, the duration of the air washing stage will be relatively long. The internal volume of the molding chamber used in related technologies is often fixed, which is not conducive to reducing the time of the air washing stage.

[0024] To address the above-mentioned issues, the present invention proposes a molding chamber with a variable volume. The present invention is described in detail below.

[0025] Figure 1 is a schematic diagram of the structure of an additive manufacturing apparatus provided in an embodiment of the present application. As shown in Figure 1 , the additive manufacturing apparatus 1 includes a molding chamber 10, a powder spreading device 20, a high-energy beam generator 30, and an air scrubber 40. In addition to the aforementioned devices, the additive manufacturing apparatus 1 may also include other devices, such as powder chambers 70a and 70b, and a molding platform 80.

[0026] The powder spreading device 20 can be used to spread metal powder in the forming chamber 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 chamber layer by layer on the forming platform 80.

[0027] The high-energy beam generator 30 can be used to generate a high-energy beam. The high-energy beam mentioned here can be a laser or another type of ion beam. Driven by a specific motion mechanism, the high-energy beam generator 30 can aim the high-energy beam at the metal powder on the forming platform 80, thereby focusing the metal powder, melting it, and then solidifying it into a shape.

[0028] The gas scrubber 40 can fill the molding chamber 10 with a gas such as helium or argon, thereby discharging the air in the molding chamber 10 and making the interior of the molding chamber 10 be in an inert gas atmosphere.

[0029] 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.

[0030] The molding chamber 10 is a molding chamber with variable volume. The molding chamber 10 has a first volume corresponding to the additive manufacturing stage and a second volume corresponding to the air washing stage, and the first volume is larger than the second volume. The so-called first volume corresponding to the additive manufacturing stage refers to the fact that in the additive manufacturing stage (or 3D printing stage), the volume of the molding chamber 10 is the first volume. The so-called second volume corresponding to the air washing stage refers to the fact that in the air washing stage (i.e. before 3D printing, or between two 3D printings), the volume of the molding chamber 10 is the second volume. Since the second volume is smaller than the first volume, it is equivalent to using a small-volume molding chamber 10 for air washing in the air washing stage, and restoring the large volume of the molding chamber to perform additive manufacturing in the additive manufacturing stage. This can shorten the air washing time and improve equipment utilization.

[0031] There are many ways to achieve variable volume of the forming chamber 10, which are described in detail below with reference to two embodiments.

[0032] Example 1

[0033] The molding chamber 10 may include a first wall portion 12 and a second wall portion 14 disposed opposite to each other. The first wall portion 12 and the second wall portion 14 are movable relative to each other to change the volume of the molding chamber 10.

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

[0035] In some implementations, the second wall portion 14 may be fixed, and the first wall portion 12 may be movable toward the second wall portion 14 .

[0036] In some implementations, the first wall portion 12 and the second wall portion 14 are both movable relative to each other.

[0037] In some implementations, as shown in Figure 2, the molding chamber 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.

[0038] 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.

[0039] Before the scrubbing begins, 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 (that is, the volume of the molding chamber 10 is the second volume mentioned above). As shown in Figure 2, 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. During 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).

[0040] The relative movement of the first wall portion 12 and the second wall portion 14 can be carried out under the control of a movable device, which can be implemented by a mechanism such as a slide rail, a gear rack, etc.

[0041] Example 2

[0042] The additive manufacturing equipment 1 may further include a retractable device 50. The retractable device 50 may be arranged inside the molding chamber 10. The volume of the retractable device 50 has a contracted state and an enlarged state. During the additive manufacturing stage, the volume of the retractable device 50 is in a contracted state, and during the air washing stage, the volume of the retractable device 50 is in an enlarged state. That is to say, during the air washing stage, the volume of the retractable device 50 is in an enlarged state, thereby occupying a larger space of the molding chamber 10, thereby reducing the space inside the molding chamber 10 that requires air washing. During the additive manufacturing stage, the retractable device 50 returns to the contracted state, so that the molding chamber 10 can process components with a larger volume.

[0043] The outer wall of the retractable device 50 is made of airtight material, thereby isolating it from the air in the space inside the molding chamber 10 .

[0044] There are many ways to implement the retractable device 50. Two possible implementation examples are given below in conjunction with FIG. 3 and FIG. 4 .

[0045] As shown in Figure 3, the retractable device 50 can be a flexible inflatable device. Further, in some implementations, the wall of the molding chamber 10 is provided with an air flow channel 60 in fluid communication with the inflatable device, so that the flexible inflatable device can be inflated and deflated through the air flow channel 60.

[0046] Exemplarily, the air flow channel 60 can be tightly connected to the side wall of the molding chamber 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 filling device (not shown in the figure). The end of the air flow channel 60 located on one side of the molding chamber 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 chamber 10). After printing is completed, the flexible expandable device can expand when filled with gas, thereby occupying the physical space in the molding chamber 10. The physical space can compress the space of the molding chamber 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 chamber 10.

[0047] In some embodiments, the flexible expandable device has a maximum expansion limit. When the scrubbing process is a vacuum process, the maximum expansion limit can ensure that the expandable device does not expand infinitely due to the vacuum level in the molding chamber, thereby causing contamination or impact on other components in the molding chamber.

[0048] As shown in FIG4 , the retractable device 50 may be a retractable accordion folding assembly (or a flexible folding assembly). The accordion folding assembly can be opened and closed inside the molding chamber 10 under the control of a movable device. The movable device may be implemented, for example, using a mechanism such as a slide rail, a gear rack, or the like.

[0049] For example, a retractable accordion folding component can be provided on one side of the molding bin 10. The flexible folding component can be moved inside the molding bin under the traction of a movable device. For example, during the additive manufacturing process, the movable device can compress the folding component close to one side of the molding bin 10 (as shown in the left figure in FIG4 ). When air washing is required after the additive manufacturing is completed, the movable device can pull the folding component to occupy most of the space in the entire molding bin 10 (as shown in the right figure in FIG4 ), thereby reducing the absolute space of the molding bin 10 and greatly saving air washing time. When the air washing is completed, the movable device pulls the folding component to be compressed onto the side wall of the molding bin 10. In this example, the folding component is made of an airtight material, which can isolate the inside and outside of the component to make it airtight. At the same time, the side wall of the folding component can be installed to connect the inside and outside of the folding component through a valve 70, so that the folding component maintains the same internal and external air pressure during the movement and is in an expanded state.

[0050] In some embodiments, when the air washing process is a vacuum 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.

[0051] In some embodiments, to cope with changes in the vacuum level within the molding chamber during the purge process, a double-layer folding assembly can be provided. The outer folding assembly has a certain strength to ensure that it does not deform due to changes in the vacuum level within the molding chamber. The inner layer of the folding assembly is made of an airtight material. This inner layer of airtight material can be flexible. When the folding assembly is filled with gas connected to the outside world so that the folding assembly occupies the space within the molding chamber, the inner layer maintains its designed shape under the influence of the outer layer. It should be understood that in this design of a double-layer folding assembly, whether the outer layer of the folding assembly is airtight becomes an optional condition.

[0052] 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 air washing process, and inert gas can be introduced into the molding chamber at the same time. This method can improve the efficiency of the air 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 in the molding chamber. 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.

[0053] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection 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 to generate 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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