Device for in-situ research of laser powder bed machining process

Abstract

The invention relates to the technical field of additive manufacturing, and particularly discloses a device for in-situ research of a laser powder bed machining process, which comprises a sealed cabin, a three-dimensional motion system, a heating platform, a sample groove and a powder feeding mechanism, the heating platform is arranged on the three-dimensional motion system; the sample tank is detachably arranged on the heating platform; the sealed cabin is provided with an incident window, an emergent window, an observation window and a laser beam passing window, and films cover the incident window and the emergent window; a camera and an infrared thermal imager are arranged outside the sealed cabin; the device for the in-situ research of the laser powder bed processing process can be combined with a synchrotron radiation technology and a neutron scattering technology to realize real-time recording of transient information such as an organization structure and temperature of a processed sample, and helps to understand phenomena such as molten pool evolution, material phase change and a defect forming process in the laser powder bed processing process; the influence of different process parameters on the tissue structure and performance of the sample can be clarified.

Description

Technical Field

[0001] The invention relates to the technical field of additive manufacturing, and in particular to a device for in-situ research of a laser powder bed machining process. Background Art

[0002] Laser powder bed processing technology includes laser cladding technology, laser powder bed melting additive manufacturing technology, etc. In the laser cladding process, the laser beam is irradiated on the powder surface. By controlling the process parameters, the powder and the substrate surface are melted and then re-solidified to achieve metallurgical bonding. In the laser powder bed melting additive manufacturing process, each layer of material is added by laser heating the powder to melt it, and then cooling and solidifying it. In the process of stacking multiple layers of materials, the material will undergo multiple thermal cycles. The solidification of each layer needs to be well combined with the next layer to ensure the integrity and strength of the part. In the laser powder bed processing technology, there are interactions between the laser and the powder, solid phase transformation of the powder and the substrate during heating, melting, solidification and cooling. In the molten pool formed by the melting of the material, phenomena such as Marangoni flow will also occur, accompanied by defects such as pores or microcracks. The phenomena involved in the processing process are very complex, and these organizational structure evolution processes usually occur in a very short time and at a microscale. The evolution of organizational structure and the formation of pores will affect the final performance of the material. It is difficult to capture the intermediate changes of the microstructure during the melting process through conventional, non-in-situ experiments, which makes it difficult to deeply reveal the phase change law, the evolution law of the molten pool and the pore formation mechanism during the melting process. Synchrotron X-ray and neutron scattering technology has the advantages of high temporal and spatial resolution and high penetration, and can characterize the material microstructure in situ and non-destructively, and can perform rapid and accurate structural analysis and imaging in a short time. In-situ experiments are carried out using synchrotron X-ray and neutron scattering technology. Laser powder bed processing experiments are carried out by adjusting process parameters such as laser power and scanning rate. At the same time, synchrotron X-ray or neutron scattering data are collected to track the phase composition and structural evolution of the material during the melting process, and to record the sputtering behavior of the powder during the interaction between the laser and the powder, the evolution of the molten pool morphology, the formation and migration of pores, etc., which can reveal the phase change law, obtain the formation mechanism of defects such as phases and pores during the melting process, and then clarify the mechanism by which process parameters such as laser power and scanning rate affect the formation of microstructure and pores, etc., and provide support for controlling the material microstructure and regulating performance by adjusting process parameters. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a device for in-situ research on laser powder bed processing, which can record in real time the phase composition and structural evolution during the melting process, the sputtering behavior of the powder during the action of the laser and the powder, the evolution of the molten pool morphology, pore formation and other transient information, to help understand the physical and chemical phenomena in the powder bed manufacturing and processing process, and combine the material structure evolution information obtained under different process parameters to help clarify the influence of different process parameters on the sample, thereby providing support for regulating the organizational structure and performance of additive manufacturing samples.

[0004] To solve the above problems, the present invention adopts the following technical solutions:

[0005] A device for in-situ research of laser powder bed processing comprises a sealed cabin, a three-dimensional motion system, a heating platform, a sample slot and a powder feeding mechanism.

[0006] The three-dimensional motion system is fixedly arranged in the sealed cabin.

[0007] The heating platform is arranged on the three-dimensional motion system and moves following the three-dimensional motion system.

[0008] The sample slot is detachably disposed on the heating platform and is heated by the heating platform.

[0009] The powder feeding mechanism is used to feed metal powder to the sample slot.

[0010] The sealed cabin is provided with an incident window, an exit window, an observation window and a laser beam passing window, and the incident and exit windows are both covered with films to seal the incident and exit windows.

[0011] The signal generated by the film and the light source does not interfere with the signal generated by the light source and the sample.

[0012] A camera is arranged outside the sealed cabin for monitoring the overall appearance of the sample stage during the processing through the observation window.

[0013] An infrared thermal imager is arranged outside the sealed cabin to record the temperature information of the processed sample during the processing.

[0014] The camera and the infrared thermal imager are both located on one side of the observation window.

[0015] In the device for in-situ research on laser powder bed machining process provided by at least one embodiment of the present disclosure, the sealed cabin also has a cabin door, and the cabin door is hingedly connected to the sealed cabin.

[0016] In the device for in-situ research on laser powder bed machining process provided by at least one embodiment of the present disclosure, the film is configured to be detachably connected to the sealed cabin.

[0017] In the device for in-situ research on laser powder bed machining process provided by at least one embodiment of the present disclosure, the powder feeding mechanism includes: a storage container and a powder feeding tube.

[0018] The storage container is fixedly arranged on the outer top surface of the sealed cabin.

[0019] The powder delivery pipe is configured to communicate with the storage container.

[0020] The top of the sealed cabin is provided with a perforation, and the powder delivery pipe is inserted into the sealed cabin through the perforation.

[0021] The device for in-situ research on the laser powder bed machining process provided by at least one embodiment of the present disclosure further includes: a protective gas supply system, wherein the protective gas supply system is used to supply protective gas to the sealed cabin.

[0022] In the device for in-situ research of laser powder bed machining process provided by at least one embodiment of the present disclosure, the sample slot is arranged in a groove shape;

[0023] The sample groove is parallel to the film.

[0024] In the device for in-situ research on laser powder bed machining process provided by at least one embodiment of the present disclosure, the powder feeding pipe is provided with an electric control valve for controlling the on-off of the powder feeding pipe.

[0025] In the device for in-situ research on laser powder bed machining process provided by at least one embodiment of the present disclosure, a gas channel is arranged on the sealed cabin, and the gas channel is configured to be connected to the protective gas supply system.

[0026] There are two gas channels.

[0027] The two gas passages are respectively arranged on both sides of the sealed cabin, and the two gas passages are distributed in high and low positions.

[0028] One of the gas channels is used to connect to the protective gas supply system.

[0029] The other gas passage is used to exhaust air.

[0030] In the device for in-situ research on laser powder bed machining process provided by at least one embodiment of the present disclosure, the three-dimensional motion system is located on the inner bottom surface of the sealed cabin.

[0031] The three-dimensional motion system is a three-axis electric control displacement platform.

[0032] In the device for in-situ research on laser powder bed machining process provided by at least one embodiment of the present disclosure, the bottom surface of the sample slot is provided with a connecting slot, the heating platform is provided with a connecting portion matching the connecting slot, and the sample slot and the heating platform are configured to be detachably connected via the connecting slot and the connecting portion.

[0033] The beneficial effects of the present invention are: it can record transient information in real time, help understand the physical and chemical phenomena of materials during laser powder bed manufacturing and processing, and combine the material structure evolution information obtained under different process parameters to help clarify the impact of different process parameters on samples, thereby providing support for regulating the structure and performance of additively manufactured samples.

[0034] The sample can be easily replaced according to the research purpose, the powder and substrate preheating function can be realized, the instantaneous temperature of the sample and the processing image can be recorded during the processing, and it can be used for synchrotron radiation X-ray and neutron scattering in-situ experiments. The film is made of polyimide film in synchrotron radiation X-ray experiments, and aluminum foil in neutron scattering in-situ experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 The figure is a schematic diagram of the internal structure of a device for in-situ research of laser powder bed machining process according to the present invention.

[0037] Figure 2 Schematic diagram of the connection between the heating platform and the sample tank.

[0038] In the figure:

[0039] 10. Sealed cabin; 11. Observation window; 12. Film; 13. Camera; 14. Gas channel; 15. Entrance window; 16. Exit window; 17. Infrared thermal imager; 18. Laser beam passing window;

[0040] 20. Three-dimensional motion system;

[0041] 30. Heating platform; 31. Connecting part;

[0042] 40. Sample slot; 41. Connection slot;

[0043] 50. Powder delivery mechanism; 51. Storage container; 52. Powder delivery pipe. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments will be described clearly and completely below in conjunction with the drawings in the embodiments. Obviously, the described embodiments are only a part of the embodiments, rather than all the embodiments.

[0045] The present invention provides a device for in-situ research on a laser powder bed machining process. When in use, metal powder is spread on a sample table, and X-rays generated by a synchrotron radiation source are injected from the left side. A protective gas can be filled into a sealed cabin to ensure that the sample is not oxidized or has other reactions with the air. The X-rays are irradiated on the sample, and signals generated by the interaction with the sample pass through an exit window, and the signals are received by a receiving screen. Background information generated by the polyimide films of the X-rays through the incident and exit windows can be distinguished and deducted later through data processing, and the experimental process is monitored by an external camera.

[0046] In neutron scattering experiments, the selected window film material needs to ensure that the neutron beam has good penetration through it, and the signal generated by the neutrons will not interfere with the experimental results. Neutrons have good penetration through aluminum foil, and the signal generated by neutrons is weak and can be easily deducted, so it is used as a window film for neutron scattering experiments.

[0047] Implementation of the device for in-situ investigation of laser powder bed machining processes Figures 1 to 2 As shown, it includes a sealed cabin 10, a three-dimensional motion system 20, a heating platform 30, a sample slot 40 and a powder feeding mechanism 50.

[0048] Specifically, the three-dimensional motion system 20 is fixedly disposed in the sealed cabin 10. The heating platform 30 is disposed on the three-dimensional motion system 20 and moves along with the three-dimensional motion system 20.

[0049] Specifically, the sample slot 40 is detachably disposed on the heating platform 30 and is heated by the heating platform 30 .

[0050] Specifically, the powder feeding mechanism 50 is used to feed metal powder to the sample slot 40 .

[0051] Specifically, the sealed cabin 10 is provided with an incident window 15, an exit window 16, an observation window 11 and a laser beam passing window 18, and the incident window 15 and the exit window 16 are both covered with a film 12 to seal the incident and exit windows 16. The signal generated by the film 12 and the light source does not interfere with the signal generated by the light source and the sample.

[0052] Furthermore, the sealed cabin 10 is in a rectangular parallelepiped shape as a whole, and the incident window 15 and the observation window 11 are both located on one side of the sealed cabin 10; three exit windows 16 are provided, one of which is located on the other side of the sealed cabin 10 and opposite to the incident window 15, and the other two exit windows 16 are located on the remaining two sides of the sealed cabin 10, and the three exit windows are used for synchronous radiation X-rays and neutron exit signals to pass through. The laser beam passing window 18 is located on the top surface of the sealed cabin 10, so that the laser beam passes through and acts on the sample.

[0053] Furthermore, in the synchrotron radiation experiment, the film 12 is made of polyimide film, and in the neutron scattering in-situ experiment, the film 12 is made of aluminum foil. When conducting the experiment, a signal receiver is placed in the direction corresponding to the exit window to receive the exiting synchrotron radiation X-ray and neutron signals.

[0054] Specifically, a camera 13 is disposed outside the sealed cabin 10, and the camera 13 is used to monitor the overall view of the sample stage during the processing through the observation window 11. An infrared thermal imager is disposed outside the sealed cabin 10, and the sealed cabin 10 is used to record the temperature information of the processed sample during the processing. The camera 13 and the infrared thermal imager are both located on one side of the observation window 11.

[0055] It should be noted that the height of the sample slot should be consistent with the center height of the incident window and the exit window, and the sample should be consistent with the incident X-ray height, so that the incident X-ray can be incident on the sample and the outgoing X-ray can pass through the exit window smoothly. The position of the sample slot is adjusted by the three-dimensional motion system 20.

[0056] In this embodiment, the sealed cabin 10 further has a cabin door (not shown), which is hingedly connected to the sealed cabin 10 ; by providing the cabin door, it is convenient for the user to operate the three-dimensional motion system 20 and to assemble and disassemble the sample tank 40 .

[0057] In this embodiment, the film 12 is configured to be detachably connected to the sealed cabin 10; the film 12 can be replaced in time according to the wear and tear, which is convenient.

[0058] Exemplarily, the film 12 is fixed to the metal frame using screws or rivets to ensure the firmness of the connection, and the metal frame is connected to the outer wall of the sealed cabin 10 using screws.

[0059] In this embodiment, the powder feeding mechanism 50 includes a storage container 51 and a powder feeding pipe 52 .

[0060] Specifically, the storage container 51 is fixedly arranged on the outer top surface of the sealed cabin 10; the powder delivery pipe 52 is arranged to be connected with the storage container 51; a through hole (not shown) is provided on the top of the sealed cabin 10, and the powder delivery pipe 52 is inserted into the sealed cabin 10 through the through hole.

[0061] Specifically, the powder delivery pipe 52 is provided with an electric control valve (not shown), and the electric control valve is used to control the on-off of the powder delivery pipe 52 .

[0062] When in use, the sample tank 40 can be moved to just below the powder delivery tube 52 by the three-dimensional motion system 20 , so that the powder can fall into the sample tank 40 .

[0063] In this embodiment, the device for in-situ research on the laser powder bed machining process further includes a protective gas supply system (not shown), which is used to supply protective gas to the sealed cabin 10 .

[0064] Specifically, a gas channel 14 is arranged on the sealed cabin 10, and the gas channel 14 is configured to be connected to the protective gas supply system; there are two gas channels 14, and the two gas channels 14 are respectively arranged on both sides of the sealed cabin 10, and the two gas channels 14 are distributed in high and low positions, one gas channel 14 is used to be connected to the protective gas supply system, and the other gas channel 14 is used to exhaust air.

[0065] In this embodiment, the sample groove 40 is provided in a groove shape, and the sample groove 40 is parallel to the film 12 .

[0066] In some embodiments, the three-dimensional motion system 20 is located on the inner bottom surface of the sealed cabin 10. The three-dimensional motion system 20 is a three-axis manual displacement platform. The three-axis manual displacement platform can flexibly adjust the position of the sample stage in the three directions of X, Y, and Z, so that experiments can be carried out conveniently, quickly, and accurately, and the experimental purpose can be achieved efficiently and quickly.

[0067] Specifically, the movement stroke of the XY axis is 100mm*100mm, the positioning accuracy of the XY axis is ±0.05mm, the movement speed of the XY axis is ≤100mm / s, and the minimum adjustment amount of the Z axis is 0.25μm.

[0068] In some embodiments, the three-dimensional motion system is an electric three-axis displacement platform, which can automatically control the position of the sample stage through programming to move the sample trough to the position directly below the powder delivery tube.

[0069] In this embodiment, a connecting groove 41 is disposed on the bottom surface of the sample groove 40 , and a connecting portion 31 matching the connecting groove 41 is disposed on the heating platform 30 . The sample groove 40 and the heating platform 30 are configured to be detachably connected via the connecting groove 41 and the connecting portion 31 .

[0070] Although the embodiments of the present application have been shown and described above, the scope of protection of the present invention is not limited thereto, and any changes or substitutions that are not conceivable through creative work should be included in the scope of protection of the present invention; unless explicitly stated, any elements, actions or instructions used in this document should not be interpreted as critical or necessary.

Claims

1. A device for in-situ research of laser powder bed processing, characterized in that: include: Sealed cabin; A three-dimensional motion system is fixedly disposed in the sealed cabin; A heating platform is arranged on the three-dimensional motion system and moves along with the three-dimensional motion system; A sample slot is detachably disposed on the heating platform and is heated by the heating platform; and A powder feeding mechanism, used for feeding metal powder to the sample tank; Wherein, the sealed cabin is provided with an incident window, an exit window, an observation window and a laser beam passing window, and the incident and exit windows are both covered with a film to seal the incident and exit windows; The signal generated by the film and the light source does not interfere with the signal generated by the light source and the sample; A camera is arranged outside the sealed cabin for monitoring the overall appearance of the sample stage during the processing through the observation window; An infrared thermal imager is arranged outside the sealed cabin to record the temperature information of the processed sample during the processing; The camera and the infrared thermal imager are both located on one side of the observation window.

2. The device for in-situ research of laser powder bed processing according to claim 1, characterized in that: The sealed cabin also has a cabin door, and the cabin door is hingedly connected to the sealed cabin.

3. The device for in-situ research of laser powder bed processing according to claim 1, characterized in that: The film is configured to be detachably connected to the sealed cabin.

4. The device for in-situ research of laser powder bed processing according to claim 1, characterized in that: The powder feeding mechanism comprises: A storage container is fixedly arranged on the outer top surface of the sealed cabin; as well as a powder delivery pipe, configured to communicate with the storage container; The top of the sealed cabin is provided with a perforation, and the powder delivery pipe is inserted into the sealed cabin through the perforation.

5. The device for in-situ research of laser powder bed processing according to claim 1, characterized in that: Also includes: The protective gas supply system is used to supply protective gas to the sealed cabin.

6. The device for in-situ research of laser powder bed processing according to claim 1, characterized in that: The sample slot is arranged in a groove shape; The sample groove is parallel to the film.

7. The device for in-situ research of laser powder bed processing according to claim 4, characterized in that: The powder delivery pipe is provided with an electric control valve for controlling the on and off of the powder delivery pipe.

8. The device for in-situ research of laser powder bed processing according to claim 5, characterized in that: The sealed cabin is provided with a gas channel, and the gas channel is configured to be connected to the protective gas supply system; The gas passages are provided with two; The two gas passages are respectively arranged on both sides of the sealed cabin, and the two gas passages are distributed in high and low positions; One of the gas channels is used to connect to the protective gas supply system; The other gas passage is used to exhaust air.

9. The device for in-situ research of laser powder bed processing according to claim 1, characterized in that: The three-dimensional motion system is located on the inner bottom surface of the sealed cabin; The three-dimensional motion system is a three-axis electric control displacement platform.

10. The device for in-situ research of laser powder bed machining process according to claim 6, characterized in that: The bottom surface of the sample slot is provided with a connecting slot, the heating platform is provided with a connecting portion that matches the connecting slot, and the sample slot and the heating platform are configured to be detachably connected via the connecting slot and the connecting portion.

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