Additive manufacturing device and method for monitoring stress evolution

Abstract

The invention discloses an additive manufacturing device and method for monitoring stress evolution, the device comprises an optical system, a powder removing mechanism, a forming system and a neutron diffractometer, the optical system is arranged at the top of the forming system, and the powder removing mechanism is arranged in the forming system; the forming system is provided with three diffraction windows, one diffraction window serves as a neutron incidence window, and the other two diffraction windows serve as neutron signal transmission windows; the neutron diffractometer is arranged outside the forming system and comprises a neutron emission gun and two neutron diffraction signal receivers; the neutron emission gun is used for emitting neutron beams at the center of the neutron incidence window, and the two neutron diffraction signal receivers are used for receiving diffraction signals penetrating through the neutron signal transmission window. The additive manufacturing device and the neutron diffractometer are combined, and operators are helped to obtain changes of internal stress of parts under different printing parameters and in the printing process.

Description

Technical Field

[0001] The present invention belongs to the technical field of additive manufacturing, and in particular relates to an additive manufacturing device and method for monitoring stress evolution. Background Art

[0002] Additive manufacturing technology is an advanced manufacturing technology that has developed rapidly in recent years and is widely used in jewelry manufacturing, aerospace, automobile manufacturing and other fields. Compared with traditional manufacturing methods, additive manufacturing has the advantages of fast speed, low cost and environmental protection. However, due to the melting and accumulation of materials during the printing process, the printed parts often face the problem of uneven internal and surface stress, which may cause deformation or even damage to the printed parts, thus affecting their function and quality. On the other hand, the internal stress of the parts is significantly affected by the printing parameters. Therefore, how to obtain the influence law of printing parameters and the internal stress of parts, clarify the changes in the internal stress of parts during the printing process, and thus reduce the stress during the forming process of parts, has become a difficult problem for additive manufacturing to further develop towards large size and high efficiency. Summary of the invention

[0003] The main purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide an additive manufacturing device and method for monitoring stress evolution.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] An additive manufacturing device for monitoring stress evolution includes an optical system, a powder removal mechanism, a forming system and a neutron diffractometer, wherein the optical system is arranged on the top of the forming system, and the powder removal mechanism is arranged inside the forming system;

[0006] The forming system is equipped with three diffraction windows, one of which is used as a neutron incident window, and the other two are used as neutron signal transmission windows;

[0007] The neutron diffractometer includes a neutron emission gun and two neutron diffraction signal receivers; the neutron emission gun and the two neutron diffraction signal receivers are arranged outside the forming system; the neutron emission gun is used to emit a neutron beam from the center of the neutron incident window, and the two neutron diffraction signal receivers are used to receive the diffraction signal transmitted from the neutron signal transmission window.

[0008] Furthermore, the forming system specifically includes a forming chamber, a forming cylinder, a feeding cylinder, and a low-neutron shielding material cover plate;

[0009] The forming cylinder and the feeding cylinder are arranged at the bottom of the forming chamber;

[0010] Diffraction windows are opened on the front, rear and left side walls of the forming chamber. The center points of the three diffraction windows are on the same horizontal plane. The diffraction window on the left is the neutron incident window, and the diffraction windows on the front and back sides are neutron signal transmission windows. The low-neutron shielding cover is set on the diffraction window for sealing, so as to realize the filling of protective gas in the forming chamber and the transmission of neutron diffraction signals.

[0011] Furthermore, the powder removal mechanism specifically includes a moving mechanism, a scraper, a powder suction port, a powder suction pipe and a mounting frame;

[0012] The moving mechanism is arranged on the upper part of the rear side wall of the forming chamber, the mounting frame is fixedly connected to the moving mechanism, the scraper and the powder suction port are both fixedly arranged on the mounting frame, and the powder suction pipe is connected to the powder suction port.

[0013] Furthermore, the moving mechanism specifically includes a motor, a slide, a ball screw, a linear guide, a synchronous belt and a synchronous wheel;

[0014] The linear guide is arranged in a groove on the rear side wall of the forming chamber, the ball screw is arranged in the groove and is located above the linear guide, the slide is connected and cooperated with the ball screw, and the mounting frame is fixed to the slide; the motor shaft and the ball screw are connected through a synchronous belt and a synchronous wheel, and the motor drives the ball screw to move the slide along the linear guide, thereby moving the scraper and the powder suction port.

[0015] Furthermore, it also includes a powder absorber, which is arranged outside the in-situ monitoring device for stress evolution in the additive manufacturing process. The powder absorber is connected to a powder suction pipe, which is connected to a powder suction port through the powder suction pipe, and is used to provide negative pressure for the powder suction port to extract powder.

[0016] Furthermore, it also includes a frame, and the forming system is fixed on the frame.

[0017] Furthermore, the optical system specifically includes a laser, a galvanometer, a field lens, a protective lens, and an optical mounting plate;

[0018] The optical mounting plate is arranged on the upper wall of the forming chamber, the galvanometer is fixed on the optical mounting plate, the field mirror is arranged below the galvanometer, the protective mirror is arranged on the upper wall of the forming chamber, and the laser is fixed on the frame.

[0019] Furthermore, a light path incident port is opened on the upper wall of the forming chamber for installing a protective mirror of the optical system and serving as a laser incident channel; a protective gas inlet and a protective gas outlet are also opened on the side wall of the forming chamber for conveying and discharging the protective gas in the forming chamber.

[0020] Furthermore, it also includes a host computer, which is connected to the optical system, powder removal mechanism, forming system and neutron diffractometer respectively, and is used to control the operation of the optical system, powder removal mechanism, forming system and neutron diffractometer, input slice file information and process neutron diffraction signals.

[0021] The present invention also includes an additive manufacturing method for monitoring stress evolution based on the provided additive manufacturing device, comprising the following steps:

[0022] S1, opening the protective gas inlet and the protective gas outlet on the side wall of the forming chamber, and passing the inert protective gas into the forming chamber through the protective gas inlet, so that the forming chamber is filled with the protective gas;

[0023] S2, the optical system selects and melts the material in the forming cylinder according to the slice file information to form the part matrix;

[0024] S3, when the part is printed to the test layer, the optical system enters the standby state, and the moving mechanism moves the powder suction port to the edge of the forming cylinder;

[0025] S4, the powder suction device starts, and the moving mechanism continues to move, driving the powder suction port to extract the powder in the forming cylinder and the surface of the formed parts;

[0026] S5, the moving mechanism is reset, the forming platform in the forming cylinder moves upward, and the part testing area is raised to the diffraction window;

[0027] S6. The neutron emission gun emits a neutron beam and injects it into the diffraction window on the left. The neutron diffraction signal receiver receives the diffraction signals of the test area from the front and rear diffraction windows to obtain the neutron diffraction signal of the part test area. After the neutron diffraction signal is processed by the host computer, the internal stress of the area is obtained.

[0028] S7, the forming platform in the forming cylinder moves downward, and the moving mechanism drives the scraper to spread a new layer of powder onto the forming plane;

[0029] S8. Repeat steps S2 to S7 until the entire part is manufactured and the stress evolution of the target area during the additive manufacturing process is measured.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] 1. The present invention combines an additive manufacturing device with a neutron diffractometer to perform quasi-in-situ real-time monitoring of the stress of the material during the printing process, obtain the stress evolution of different areas of the parts and under different forming processes during the additive manufacturing process, and provide an effective means for optimizing the forming process of different parts and different materials, helping researchers to improve the reliability and stability of additive manufacturing technology in the manufacture of complex parts.

[0032] 2. The present invention realizes full automation through the combination of additive manufacturing equipment and powder removal mechanism; the powder removal mechanism is added to the additive manufacturing equipment so that the parts to be tested can be completely exposed from the powder bed, thereby improving the accuracy of the test, and through the fully automated forming, cleaning, and testing process, the danger of long-term exposure to the radiation environment during manual cleaning of powder is avoided, thereby improving the detection efficiency.

[0033] 3. The stress evolution detection based on the same part has extremely high accuracy. Although the method of using parts in multiple different printing stages for stress measurement comparison can also indirectly obtain the stress changes of parts in different printing stages, it is difficult to make the printing conditions of parts from different batches completely consistent, which will lead to differences in detection, thereby reducing the accuracy of the results. The device and method proposed in the present invention can avoid the influence of differences between parts from different batches on the results, greatly improving the accuracy of the results. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is an overall schematic diagram of the device of the present invention;

[0035] Figure 2 It is a structural schematic diagram of the forming system;

[0036] Figure 3 It is a schematic diagram of the front diffraction window and the powder absorber;

[0037] Figure 4 is a schematic diagram of the structure of the powder removal mechanism;

[0038] Explanation of the accompanying drawings: 1-optical system; 2-forming system; 21-forming chamber; 22-forming cylinder; 23-feeding cylinder; 24-low-neutron shielding material cover; 25-left diffraction window; 26-front diffraction window; 27-rear diffraction window; 31-moving mechanism; 32-scraper; 33-powder suction port; 34-powder suction pipe; 35-mounting frame; 36-powder absorber. DETAILED DESCRIPTION

[0039] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0040] Example

[0041] like Figure 1 , Figure 2 , Figure 3 as well as Figure 4 As shown, the present invention is an additive manufacturing device for monitoring stress evolution, comprising an optical system 1, a powder removing mechanism, a forming system 2, a neutron diffractometer and a frame; the optical system is arranged on the top of the forming system, the powder removing mechanism is arranged inside the forming system; the forming system is fixed on the frame.

[0042] The optical system is used to provide energy during the forming process, and the powder removal mechanism provides an environment for the stress evolution monitoring process.

[0043] In this embodiment, the forming system specifically includes a forming chamber 21, a forming cylinder 22, a feeding cylinder 23, and a low-neutron shielding material cover plate 24;

[0044] The forming cylinder and the feeding cylinder are arranged at the bottom of the forming chamber; the forming cylinder is used to control the lifting and lowering of the parts during the forming process so that the forming plane is consistent with the focal plane of the optical system; the feeding cylinder is used to supply powder during the forming process.

[0045] Diffraction windows are provided on the front, rear and left side walls of the forming chamber, namely the left diffraction window 25, the front diffraction window 26 and the rear diffraction window 27. The center points of the three diffraction windows are in the same horizontal plane. The left diffraction window is the neutron incident window, and the front diffraction window and the rear diffraction window are the neutron signal transmission windows. The low-neutron shielding cover is arranged on the diffraction window for sealing, so as to realize the filling of protective gas in the forming chamber and the transmission of neutron diffraction signals.

[0046] In this embodiment, the neutron diffractometer includes a neutron emission gun and two neutron diffraction signal receivers; Figure 1 As shown, the neutron emission gun is mounted on the left side of the outside of the forming system and is aimed at the left diffraction window; two neutron diffraction signal receivers are respectively mounted on the front and rear sides of the outside of the forming system and are respectively aimed at the front diffraction window and the rear diffraction window; the neutron emission gun is used to emit a neutron beam from the center of the neutron incident window, and the two neutron diffraction signal receivers are used to receive the diffraction signal transmitted through the neutron signal transmission window.

[0047] In this embodiment, the powder removal mechanism specifically includes a moving mechanism 31, a scraper 32, a powder suction port 33, a powder suction pipe 34 and a mounting frame 35;

[0048] The moving mechanism is arranged on the upper part of the rear side wall of the forming chamber to avoid blocking the neutron diffraction signal; the mounting frame is fixedly connected to the moving mechanism, the scraper and the powder suction port are fixedly arranged on the mounting frame, and the powder suction pipe is connected to the powder suction port.

[0049] In this embodiment, the moving mechanism specifically includes a motor, a slide, a ball screw, a linear guide rail, a synchronous belt and a synchronous wheel;

[0050] The linear guide is arranged in a groove on the rear side wall of the forming chamber, the ball screw is arranged in the groove and is located above the linear guide, the slide is connected and cooperated with the ball screw, and the mounting frame is fixed to the slide; the motor shaft and the ball screw are connected through a synchronous belt and a synchronous wheel, and the motor drives the ball screw to move the slide along the linear guide, thereby moving the scraper and the powder suction port.

[0051] In this embodiment, a powder absorber 36 is also included. The powder absorber is arranged outside the in-situ monitoring device for stress evolution in the additive manufacturing process. The powder absorber is connected to a powder suction pipe, which is connected to a powder suction port through the powder suction pipe, and is used to provide negative pressure for the powder suction port to extract powder.

[0052] In this embodiment, the optical system specifically includes a laser, a galvanometer, a field lens, a protective lens, and an optical mounting plate;

[0053] The optical mounting plate is arranged on the upper wall of the forming chamber, the galvanometer is fixed on the optical mounting plate, the field mirror is arranged below the galvanometer, the protective mirror is arranged on the upper wall of the forming chamber, and the laser is fixed on the frame.

[0054] In this embodiment, a light path incident port is opened on the upper wall of the forming chamber for installing a protective mirror of the optical system and serving as a laser incident channel; a protective gas inlet and a protective gas outlet are opened on the side wall of the forming chamber for conveying and discharging the protective gas in the forming chamber.

[0055] In this embodiment, a host computer is also included, which is connected to the optical system, the powder removing mechanism, the forming system and the neutron diffractometer respectively, and is used to control the operation of the optical system, the powder removing mechanism, the forming system and the neutron diffractometer, the input of slice file information and the processing of neutron diffraction signals.

[0056] In another embodiment, an additive manufacturing method for monitoring stress evolution based on the device of the above embodiment is also provided, comprising the following steps:

[0057] S1, opening the protective gas inlet and the protective gas outlet on the side wall of the forming chamber, and passing the inert protective gas into the forming chamber through the protective gas inlet, so that the forming chamber is filled with the protective gas;

[0058] S2, the optical system selects and melts the material in the forming cylinder according to the slice file information to form the part matrix;

[0059] S3, when the part is printed to the test layer, the optical system enters the standby state, and the moving mechanism moves the powder suction port to the edge of the forming cylinder;

[0060] S4, the powder suction device starts, and the moving mechanism continues to move, driving the powder suction port to extract the powder in the forming cylinder and the surface of the formed parts;

[0061] S5, the moving mechanism is reset, the forming platform in the forming cylinder moves upward, and the part testing area is raised to the diffraction window;

[0062] S6. The neutron emission gun emits a neutron beam and injects it into the diffraction window on the left. The neutron diffraction signal receiver receives the diffraction signals of the test area from the front and rear diffraction windows to obtain the neutron diffraction signal of the part test area. After the neutron diffraction signal is processed by the host computer, the internal stress of the area is obtained.

[0063] S7, the forming platform in the forming cylinder moves downward, and the moving mechanism drives the scraper to spread a new layer of powder onto the forming plane;

[0064] S8. Repeat steps S2 to S7 until the entire part is manufactured and the stress evolution of the target area during the additive manufacturing process is measured.

[0065] It should also be noted that in this specification, terms such as "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0066] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An additive manufacturing device for monitoring stress evolution, It is characterized in that It includes an optical system, a powder removal mechanism, a forming system and a neutron diffractometer, wherein the optical system is arranged on the top of the forming system, and the powder removal mechanism is arranged inside the forming system; The forming system is equipped with three diffraction windows, one of which is used as a neutron incident window, and the other two are used as neutron signal transmission windows; The neutron diffractometer includes a neutron emission gun and two neutron diffraction signal receivers; the neutron emission gun and the two neutron diffraction signal receivers are arranged outside the forming system; the neutron emission gun is used to emit a neutron beam from the center of the neutron incident window, and the two neutron diffraction signal receivers are used to receive the diffraction signal transmitted from the neutron signal transmission window.

2. An additive manufacturing device for monitoring stress evolution according to claim 1, It is characterized in that The forming system specifically includes a forming chamber, a forming cylinder, a feeding cylinder and a low-neutron shielding material cover plate; The forming cylinder and the feeding cylinder are arranged at the bottom of the forming chamber; Diffraction windows are opened on the front, rear and left side walls of the forming chamber. The center points of the three diffraction windows are on the same horizontal plane. The diffraction window on the left is the neutron incident window, and the diffraction windows on the front and back sides are neutron signal transmission windows. The low-neutron shielding cover is set on the diffraction window for sealing, so as to realize the filling of protective gas in the forming chamber and the transmission of neutron diffraction signals.

3. The additive manufacturing device for monitoring stress evolution according to claim 1, It is characterized in that The powder removal mechanism specifically includes a moving mechanism, a scraper, a powder suction port, a powder suction pipe and a mounting frame; The moving mechanism is arranged on the upper part of the rear side wall of the forming chamber, the mounting frame is fixedly connected to the moving mechanism, the scraper and the powder suction port are both fixedly arranged on the mounting frame, and the powder suction pipe is connected to the powder suction port.

4. The additive manufacturing device for monitoring stress evolution according to claim 3, It is characterized in that The moving mechanism specifically includes a motor, a slide, a ball screw, a linear guide, a synchronous belt and a synchronous wheel; The linear guide is arranged in a groove on the rear side wall of the forming chamber, the ball screw is arranged in the groove and is located above the linear guide, the slide is connected and cooperated with the ball screw, and the mounting frame is fixed to the slide; the motor shaft and the ball screw are connected through a synchronous belt and a synchronous wheel, and the motor drives the ball screw to move the slide along the linear guide, thereby moving the scraper and the powder suction port.

5. The additive manufacturing device for monitoring stress evolution according to claim 3, It is characterized in that It also includes a powder absorber, which is arranged outside the in-situ monitoring device for stress evolution in the additive manufacturing process. The powder absorber is connected to a powder suction pipe, which is connected to a powder suction port through the powder suction pipe, and is used to provide negative pressure for the powder suction port to extract powder.

6. The additive manufacturing device for monitoring stress evolution according to claim 1, It is characterized in that The utility model also comprises a frame, on which the forming system is fixedly arranged.

7. The additive manufacturing device for monitoring stress evolution according to claim 6, It is characterized in that The optical system specifically includes a laser, a galvanometer, a field lens, a protective lens, and an optical mounting plate; The optical mounting plate is arranged on the upper wall of the forming chamber, the galvanometer is fixed on the optical mounting plate, the field mirror is arranged below the galvanometer, the protective mirror is arranged on the upper wall of the forming chamber, and the laser is fixed on the frame.

8. The additive manufacturing device for monitoring stress evolution according to claim 7, It is characterized in that An optical path incident port is opened on the upper wall of the forming chamber for installing a protective mirror of the optical system and serving as a laser incident channel; a protective gas inlet and a protective gas outlet are also opened on the side wall of the forming chamber for conveying and discharging the protective gas in the forming chamber.

9. The additive manufacturing device for monitoring stress evolution according to claim 1, It is characterized in that It also includes a host computer, which is connected to the optical system, the powder removing mechanism, the forming system and the neutron diffractometer respectively, and is used to control the operation of the optical system, the powder removing mechanism, the forming system and the neutron diffractometer, input slice file information and process neutron diffraction signals.

10. An additive manufacturing method for monitoring stress evolution based on the device according to any one of claims 1 to 9, It is characterized in that The following steps are involved: S1, opening the protective gas inlet and the protective gas outlet on the side wall of the forming chamber, and passing the inert protective gas into the forming chamber through the protective gas inlet, so that the forming chamber is filled with the protective gas; S2, the optical system selects and melts the material in the forming cylinder according to the slice file information to form the part matrix; S3, when the part is printed to the test layer, the optical system enters the standby state, and the moving mechanism moves the powder suction port to the edge of the forming cylinder; S4, the powder suction device starts, and the moving mechanism continues to move, driving the powder suction port to extract the powder in the forming cylinder and the surface of the formed parts; S5, the moving mechanism is reset, the forming platform in the forming cylinder moves upward, and the part testing area is raised to the diffraction window; S6. The neutron emission gun emits a neutron beam and injects it into the diffraction window on the left. The neutron diffraction signal receiver receives the diffraction signals of the test area from the front and rear diffraction windows to obtain the neutron diffraction signal of the part test area. After the neutron diffraction signal is processed by the host computer, the internal stress of the area is obtained. S7, the forming platform in the forming cylinder moves downward, and the moving mechanism drives the scraper to spread a new layer of powder onto the forming plane; S8. Repeat steps S2 to S7 until the entire part is manufactured and the stress evolution of the target area during the additive manufacturing process is measured.

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