A recirculating air field system for selective laser sintering and an additive manufacturing apparatus

Abstract

The utility model provides a circulating air field system for selective laser sintering and additive manufacturing equipment, wherein the air field system comprises a cross flow fan, a filter screen, a circulating filter, a dust collector, a circulating fan, a partition plate and an air pipe, the partition plate is vertically arranged in a working cavity to divide the working cavity into an inner working cavity and an outer working cavity, an upper air outlet is arranged at the upper part of the partition plate, a lower air outlet is arranged at the bottom of the partition plate, a ventilation opening is arranged at the middle part of the partition plate, the cross flow fan is arranged in the upper air outlet, the filter screen is arranged in the ventilation opening, a suction opening is arranged at the bottom of the side wall of the inner working cavity opposite to the partition plate, one end of the air pipe penetrates through the outer working cavity and extends to be connected to the lower air outlet, the other end of the air pipe is connected to the suction opening, and the dust collector, the circulating filter and the circulating fan are sequentially arranged in the air pipe from the suction opening to the lower air outlet. The utility model not only simplifies the equipment structure and reduces the equipment cost, but also reduces the heat loss of the printed workpiece in the working cavity during the printing process, thereby reducing the internal stress during the printing process of the workpiece and improving the printing quality of the workpiece.

Description

Technical Field

[0001] This utility model belongs to the field of additive manufacturing technology, specifically relating to a circulating air field system for selective laser sintering and additive manufacturing equipment. Background Technology

[0002] Additive manufacturing is a rapid manufacturing technology that uses a laser to scan and stack layers to form a three-dimensional object. Selective laser sintering (SLS), one type of additive manufacturing technology, has the following process: First, the three-dimensional model of the workpiece is sliced ​​to obtain the cross-sectional information of each layer. Powdered material is evenly spread on the surface of the work platform, and the laser selectively melts the powder according to system instructions. After one cross-section is completed, a new layer of material is spread on it, and the laser continues to selectively scan according to the cross-sectional information of the three-dimensional object. This process is repeated for the next cross-section, and finally, the three-dimensional object is obtained.

[0003] In additive manufacturing, high-power lasers from laser scanning systems are typically used to directly act on metal powder, causing it to melt and solidify rapidly. When a high-energy laser acts on a molten metal pool, thermodynamics excites some of the molten metal, causing it to cool rapidly in the air and form black fumes. Simultaneously, sintered powder splatter also occurs. These two substances have three adverse effects: first, they pollute the environment within the working chamber; second, they cause diffuse reflection of the laser in the air within the working chamber, reducing the energy of the laser on the powder; and third, if left embedded in the workpiece, they reduce the workpiece's density, leading to a decrease in quality. Therefore, effective fume treatment is an essential part of additive manufacturing technology.

[0004] Current methods for handling dust typically involve introducing inert gas through an airflow system to carry away powder splashes and black fumes generated during workpiece sintering. The fumes are then filtered by an external circulating filter system, and the inert gas is recycled. However, existing airflow structures often involve two or three layers of vents connected from outside the working chamber. This makes the airflow structure more complex and increases equipment costs. Furthermore, the airflow circulates through the external filter, carrying away some heat from the working chamber, increasing the temperature difference between the printed workpiece and the working chamber environment. This leads to increased residual stress inside the printed workpiece, thus increasing the risk of cracking. Utility Model Content

[0005] To address the aforementioned technical problems in the existing technology, this utility model provides a circulating airflow system for selective laser sintering and an additive manufacturing device. This circulating airflow system not only simplifies the equipment structure and reduces equipment costs, but also reduces heat loss of the printed workpiece within the working cavity during the printing process, i.e., reduces the temperature difference between the working cavity and the printed workpiece, thereby reducing internal stress during the workpiece printing process and improving the printing quality of the workpiece.

[0006] To achieve the above objectives, this utility model provides a circulating airflow system for selective laser sintering, comprising a crossflow fan, at least one filter, a circulating filter, a dust collector, a circulating fan, a partition, and an air duct. The partition is vertically arranged within the working chamber to divide the working chamber into an inner working chamber and an outer working chamber, and the top of the inner working chamber is completely covered by a window mirror installed at the top of the working chamber. The upper part of the partition is provided with an upper air outlet, the bottom part with a lower air outlet, and the middle part with at least one ventilation opening. The crossflow fan is located inside the upper air outlet, and the filter is located inside the ventilation opening. An air intake is located at the bottom of the side wall of the inner working chamber opposite to the partition. One end of the air duct penetrates the outer working chamber and extends to connect with the lower air outlet, and the other end of the air duct connects to the air intake. The dust collector, the circulating filter, and the circulating fan are sequentially arranged in the air duct from the air intake to the lower air outlet.

[0007] As a further preferred embodiment of this utility model, the lower air outlet and the air intake are located at the same height.

[0008] As a further preferred embodiment of this utility model, the distance from the bottom of the air intake to the bottom of the inner working chamber is 0-5mm.

[0009] As a further preferred embodiment of this utility model, the distance from the top of the upper air outlet to the top of the inner working cavity is 0-5mm.

[0010] As a further preferred embodiment of this utility model, there are two ventilation openings.

[0011] As a further preferred embodiment of this utility model, the two ventilation openings are located on both sides of the vertical line where the upper air outlet is located.

[0012] As a further preferred embodiment of this utility model, the inner working cavity is used for sintering and forming the workpiece to be printed.

[0013] As a further preferred embodiment of this utility model, the outer working cavity is used to place the printing device.

[0014] As a further preferred embodiment of this utility model, the printing device includes a wind field device and a scraper movement device.

[0015] This utility model also provides an additive manufacturing apparatus, including a working chamber, a window mirror disposed at the top of the working chamber, and a circulating air field system for selective laser sintering as described in any of the above.

[0016] This invention relates to a circulating airflow system for selective laser sintering and an additive manufacturing equipment. A partition is vertically positioned within the working chamber to divide it into an inner and outer working chamber. This allows the working chamber to include both an inner and outer circulation structure. The inner circulation structure consists of an upper air outlet, a crossflow fan, and a filter, creating a stable parallel airflow above the workpiece in the inner working chamber. This not only forms a protective airflow below the window mirror, carrying away some of the smoke and powder splashes generated during printing and protecting the window mirror from contamination, but also reduces heat loss from the workpiece within the working chamber during printing. This reduces the temperature difference between the working chamber and the workpiece, thereby lowering internal stress during printing and improving print quality. Moreover, the external circulation structure consists of a lower air outlet and an air inlet connected to an external air duct, dust collector, circulating filter, and circulating fan, which can carry away the remaining smoke and dust. In addition, since the wind field system of this utility model only adopts a partial external circulation structure and a partial internal circulation structure, it simplifies the equipment structure to a certain extent, reduces the space occupied, and saves equipment costs. Attached Figure Description

[0017] Figure 1 A schematic diagram of a structural embodiment of the circulating air field system for selective laser sintering of this utility model;

[0018] Figure 2 This is a cross-sectional view of the partition plate of this utility model.

[0019] The components in the diagram are marked as follows:

[0020] 1. Inner working chamber, 2. Window mirror, 3. Partition, 4. Crossflow fan, 5. Outer working chamber, 6. Air duct, 7. Circulating fan, 8. Circulating filter, 9. Filter screen, 10. Dust collector, 11. Lower air outlet, 12. Air inlet, 13. Upper air outlet. Detailed Implementation

[0021] To enable those skilled in the art to better understand and implement the technical solution of this utility model, the following will provide a more detailed description in conjunction with the accompanying drawings and specific embodiments.

[0022] like Figure 1 and Figure 2As shown, the circulating airflow system for selective laser sintering of this utility model includes a crossflow fan 4, at least one filter screen 9, a circulating filter 8, a dust collector 10, a circulating fan 7, a partition 3, and an air duct 6. The partition 3 is vertically arranged in the working chamber to divide the working chamber into an inner working chamber 1 and an outer working chamber 5, and the top of the inner working chamber 1 is completely covered by a window mirror 2 installed at the top of the working chamber. The upper part of the partition 3 is provided with an upper air outlet 13, the bottom is provided with a lower air outlet 11, and the middle part is provided with a lower air outlet 11. The inner working chamber is equipped with at least one ventilation opening. The crossflow fan 4 is located inside the upper air outlet 13, and the filter screen 9 is located inside the ventilation opening. An air intake 12 is located at the bottom of the side wall opposite to the partition 3 of the inner working chamber 1. One end of the air duct 6 passes through the outer working chamber 5 and extends to connect with the lower air outlet 11. The other end of the air duct 6 connects to the air intake 12. The dust collector 10, the circulating filter 8, and the circulating fan 7 are sequentially arranged in the air duct 6 from the air intake 12 to the lower air outlet 11. The entire working chamber (including the inner working chamber 1 and the outer working chamber 5) is sealed to ensure normal printing of the workpiece. To facilitate the installation of the air duct 6, one end of the air duct 6 is threaded onto the side wall of the outer working chamber 5, and the other end is threaded onto the bottom of the side wall opposite to the partition 3 of the inner working chamber 1, and is connected to the air intake 12.

[0023] The selective laser sintering circulating air field system of this application includes two circulating structures, inner and outer, and therefore includes two circulating air paths. The printing process of the workpiece is completed in the inner working cavity 1. In the lower-level external circulation air path, inert gas enters the inner working chamber 1 from the lower outlet 11 and is drawn in by the suction port 12, forming a horizontal airflow at the bottom of the inner working chamber 1. This airflow carries away the powder splashes and dust generated during the printing process. Larger dust particles in the gas are then collected by the duct 6 and dust collector 10, and filtered by the circulation filter 8 to meet the operating conditions. Finally, the gas is sent to the lower outlet 11 by the circulation fan 7 through the duct 6, thus entering the inner working chamber 1. In the upper-level circulation air path, the gas in the inner working chamber 1 is filtered by the filter screen 9 and enters the outer working chamber 5. It then enters the inner working chamber 1 through the crossflow fan 4 and the upper outlet 13, forming a horizontal airflow in the area below the window mirror 2. This airflow carries away the powder splashes and dust generated during the printing process in the upper part of the inner working chamber 1, and then enters the circulation air path through the suction port 12 and the filter screen 9.

[0024] In one specific implementation, the lower air outlet 11 and the air intake 12 are located at the same height. Preferably, the distance from the bottom of the air intake 12 to the bottom of the inner working cavity 1 (e.g., Figure 2 The H2 in the middle is 0-5mm to ensure that the airflow formed at the bottom of the inner working cavity 1 can promptly carry away the powder splashes and dust generated during the printing process.

[0025] More preferably, the distance from the top of the upper air outlet 13 to the top of the inner working cavity 1 (e.g., Figure 2 The H1 in the middle is 0-5mm to ensure that the airflow formed at the top of the inner working cavity 1 is close to the window mirror 2, so as to better protect the window mirror 2 from contamination.

[0026] In another specific implementation, there are two ventilation openings. Specifically, the two ventilation openings are located on either side of the vertical line where the upper air outlet 13 is located. Of course, in a specific implementation, there can also be multiple ventilation openings, such as three, the specific number of which can be determined according to specific needs, and will not be listed here.

[0027] Specifically, the inner working cavity 1 is used for sintering and forming the workpiece to be printed; the outer working cavity 5 is used to place printing devices, such as airflow devices, scraper movement devices, etc.

[0028] This utility model also provides an additive manufacturing apparatus, including a working chamber, a window mirror 2 disposed at the top of the working chamber, and a circulating air field system for selective laser sintering as described in any of the above embodiments. It should be noted that the additive manufacturing apparatus of this application also includes other existing components, such as a scanning system and a powder spreading device. Since the core protection of this application lies in the circulating air field system for selective laser sintering, the other existing components included in the additive manufacturing apparatus will not be specifically described here.

[0029] The above embodiments are merely preferred embodiments of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model should be considered within the protection scope of this utility model. It should be noted that any modifications and alterations made without departing from the principle of this utility model should be considered within the protection scope of this utility model.

Claims

1. A circulating airflow system for selective laser sintering, characterized in that, The device includes a crossflow fan, at least one filter, a circulating filter, a dust collector, a circulating fan, a partition, and a duct. The partition is vertically arranged within the working chamber to divide the working chamber into an inner working chamber and an outer working chamber, and the top of the inner working chamber is completely covered by a window mirror installed at the top of the working chamber. The upper part of the partition is provided with an upper air outlet, the bottom part with a lower air outlet, and at least one ventilation opening in the middle. The crossflow fan is located inside the upper air outlet, and the filter is located inside the ventilation opening. An air intake is provided at the bottom of the side wall of the inner working chamber opposite to the partition. One end of the duct penetrates the outer working chamber and extends to connect with the lower air outlet, and the other end of the duct connects to the air intake. The dust collector, the circulating filter, and the circulating fan are arranged sequentially in the duct from the air intake to the lower air outlet.

2. The circulating airflow system for selective laser sintering according to claim 1, characterized in that, The lower air outlet and air intake are located at the same height.

3. The circulating airflow system for selective laser sintering according to claim 2, characterized in that, The distance from the bottom of the air intake to the bottom of the inner working chamber is 0-5mm.

4. The circulating airflow system for selective laser sintering according to claim 1, characterized in that, The distance from the top of the upper air outlet to the top of the inner working cavity is 0-5mm.

5. The circulating airflow system for selective laser sintering according to claim 1, characterized in that, There are two ventilation openings.

6. The circulating airflow system for selective laser sintering according to claim 5, characterized in that, The two ventilation openings are located on either side of the vertical line where the upper air outlet is located.

7. The circulating airflow system for selective laser sintering according to claim 1, characterized in that, The inner working cavity is used for sintering and forming the workpiece to be printed.

8. The circulating airflow system for selective laser sintering according to any one of claims 1 to 7, characterized in that, The outer working cavity is used to house the printing device.

9. The circulating airflow system for selective laser sintering according to claim 8, characterized in that, The printing device includes a wind field device and a scraper movement device.

10. An additive manufacturing apparatus, characterized in that, It includes a working chamber, a window mirror disposed at the top of the working chamber, and a circulating air field system for selective laser sintering as described in any one of claims 1 to 9.

Images