Powder spreading device for a laser powder bed fusion apparatus and method thereof

Abstract

The application provides a powder spreading device for a laser selective melting equipment and a method thereof, the powder spreading device comprises a forming cabin, a forming system with a printing substrate, a powder spreading system with a plurality of switchable scrapers, a powder recycling system, a laser light path system for melting the laid metal powder on the printing substrate of the forming system according to a preset printing program, a brush moving system capable of reciprocating on the upper surface of the powder recycling system and brushing off the powder sticking to the lower surface of the scraper during the reciprocation, an optical imaging monitoring system comprising a CCD camera for shooting a powder spreading image of each layer of powder spreading, and a control system for controlling the brush moving system to clean the powder sticking to the scraper and automatically switching the scraper according to the comparison result of the quality of the powder spreading image. The powder spreading system and the method thereof can solve the problem that the printing task cannot be completed with quality and quantity due to the wear of the powder spreading scraper during the long-time printing process of the laser selective melting equipment.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, particularly laser selective melting technology, and more specifically to a powder spreading device and method for laser selective melting equipment. Background Technology

[0002] Laser selective melting (LSM) metal 3D printers are high-end 3D printing equipment developed in recent years to adapt to the small-batch production of single-piece metal parts. They are suitable for various materials such as stainless steel, mold steel, aluminum alloys, nickel alloys, and titanium alloys. LSM printers offer advantages such as no need for mold making, digitalization, environmental friendliness, and facilitating rapid product iteration by the design team. They are increasingly favored in industries such as aerospace, mold making, automotive, dental, nuclear power, and petrochemicals. With the continuous expansion of demand, related technologies for LSM equipment have also been updated and developed, significantly improving the range, quality, and efficiency of the forming process.

[0003] As the forming size of equipment continues to increase, the structural forms of the parts to be produced become more and more diverse, and the requirements for the stability of the equipment during long-term printing become higher and higher. The uniformity of powder spreading in the forming chamber during the printing process is directly related to the stability of the forming quality of the parts. In addition to the printing process and powder quality, the structure and motion control system of the powder spreading system are key factors affecting the powder spreading quality, influencing the entire printing process and the forming quality. Summary of the Invention

[0004] The purpose of this invention is to provide a powder spreading device for laser selective melting equipment, which aims to solve the problem that the printing task cannot be completed with guaranteed quality and quantity due to the wear of the powder spreading scraper during long-term printing in laser selective melting equipment.

[0005] To achieve the above objectives, according to a first aspect of the present invention, a powder spreading device for a laser selective melting equipment is provided, capable of monitoring printing quality and automatically changing the doctor blade, comprising:

[0006] Molded compartment;

[0007] A molding system having a printing substrate located within the molding chamber;

[0008] The powder spreading system is located inside the forming chamber and on one side of the forming system. It has multiple squeegees that can switch between working positions. When any squeegee is switched to the working position, it can move along the powder spreading direction to spread metal powder from the powder feeder onto the surface of the printing substrate.

[0009] A powder recovery system, located inside the molding chamber and on the other side of the molding system, is used to recover powder.

[0010] The laser optical path system is located above the molding chamber and is used to melt the metal powder laid on the printing substrate of the molding system according to the preset printing program.

[0011] The brush motion system is located inside the forming chamber and can be driven to reciprocate on the upper surface of the powder return system, brushing away the sticky powder on the lower surface of the scraper during the reciprocating motion.

[0012] An optical imaging monitoring system includes at least one CCD camera oriented toward the molding system for capturing images of each layer of powder.

[0013] The control system is configured to control the reciprocating motion of the brush motion system to clean the powder adhering to the scraper and automatically switch scrapers based on the quality comparison results of the powder spreading image.

[0014] In an optional embodiment, the control system is configured to control the brush motion system to periodically clean the scraper according to a preset number of powder layers.

[0015] In an optional embodiment, the control system controls to pause printing and control the brush motion system to clean the scraper based on fine or deep scratches present in the powder-spreading image.

[0016] In an optional embodiment, the fine marks refer to powder-spreading marks with a width exceeding a preset value, and the deep marks refer to powder-spreading marks with a depth or height exceeding a preset value.

[0017] In an optional embodiment, the control system controls the brush motion system to clean the scraper based on the fine or deep marks present in the toner-spreading image, then controls the re-spreading of toner and compares the toner-spreading image. If the fine or deep marks still exist, the control system controls the replacement of the scraper; otherwise, the current scraper is used to continue printing.

[0018] In an optional embodiment, the powder spreading device further includes:

[0019] The reference plane located between the forming system and the powder return system serves as a reference plane for leveling the scraper.

[0020] During the printing process, as the toner spreading system spreads toner with its scraper and moves toward the toner return system, the reference plane is covered with toner. The toner accumulation at the reference plane position is photographed by a CCD camera to determine the wear of the scraper.

[0021] The control system is configured to switch the scraper in the powder spreading system when the powder spreading area in the region exceeds a set threshold.

[0022] In an optional embodiment, the powder spreading system includes a slider, a motor, a rotary motion shaft, a scraper clamp, a scraper, a scraper holder, and a cantilever beam;

[0023] The scraper holder is cylindrical and is installed horizontally inside the cantilever beam;

[0024] The motor is fixed on the cantilever beam and connected to the cylindrical scraper frame via a rotary motion shaft, for driving the cylindrical scraper frame to transmit power along its central axis; the output shaft of the motor, the rotary motion shaft and the scraper frame are coaxially mounted.

[0025] Multiple scrapers are mounted on the surface of the scraper holder by their respective scraper clamps, and each scraper is mounted along the length of the scraper holder;

[0026] The slider is fixed to the outside of the cantilever beam and connected to the powder spreading motion control system installed in the molding chamber. The control system drives the slider to move, thereby making the cantilever beam and the scraper move synchronously to achieve powder spreading.

[0027] The control system can control the movement of the motor to control the rotation of the scraper frame, thereby switching the scraper.

[0028] In an optional embodiment, the plurality of scrapers includes soft scrapers made of rubber and hard scrapers made of ceramic or high-speed steel.

[0029] According to a second aspect of the present invention, a powder spreading method for a laser selective melting device is also provided, the powder spreading method comprising the following steps:

[0030] During the printing process, the CCD camera captures images of each layer of powder to obtain powder-spreading images;

[0031] Identify whether there are fine or deep scratches in the powder-spreading image:

[0032] If fine or deep scratches are present, the system pauses printing and controls the brush motion system to reciprocate on the surface of the toner return system to clean the toner stuck to the bottom of the scraper. After cleaning, the system re-spreads toner and takes a toner-spreading image, then compares the toner-spreading image again. If fine or deep scratches still exist, the system replaces the scraper; otherwise, printing continues using the currently cleaned scraper.

[0033] In an optional embodiment, the powder spreading method further includes the following steps:

[0034] A reference plane is set at the midpoint between the forming system and the powder return system, serving as a reference surface for leveling the scraper;

[0035] During the printing process, as the toner spreading system spreads toner with its scraper and moves toward the toner return system, the reference plane is covered with toner. The toner accumulation at the reference plane position is photographed by the CCD camera to determine the wear of the scraper.

[0036] The control system is used to control the powder spreading system to switch the scraper when the powder spreading area in the region exceeds a set threshold.

[0037] In an optional embodiment, the powder spreading method further includes the following steps:

[0038] The scraper cleaning cycle is pre-configured. After the powder spreading system completes the preset number of powder layers, printing is paused, and the brush motion system is controlled to reciprocate on the upper surface of the powder return system to scrape off the powder adhering to the lower surface of the scraper and perform periodic cleaning of the scraper.

[0039] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below may be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other. Furthermore, all combinations of the claimed subject matter are considered part of the inventive subject matter of this disclosure.

[0040] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0041] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings.

[0042] Figure 1 This is a schematic diagram of a powder spreading device for a laser selective melting equipment according to an embodiment of the present invention.

[0043] Figure 2 This is a schematic diagram of a powder spreading system according to an embodiment of the present invention. Detailed Implementation

[0044] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0045] Various aspects of the invention are described in this disclosure with reference to the accompanying drawings, which illustrate numerous illustrative embodiments. The embodiments of this disclosure are not necessarily intended to encompass all aspects of the invention. It should be understood that the various concepts and embodiments described above, as well as those described in more detail below, can be implemented in any of many ways, because the concepts and embodiments disclosed herein are not limited to any particular implementation. Furthermore, some aspects of the invention disclosed may be used alone or in any suitable combination with other aspects of the invention disclosed.

[0046] {Powder spreading device for laser selective melting equipment}

[0047] Combination Figure 1 As shown, the powder spreading device for a laser selective melting equipment according to an embodiment of the present invention includes a forming chamber 100, a forming system 110, a powder spreading system 120, a powder return system 130, a laser optical path system 140, a brush motion system 150, an optical imaging monitoring system 160, and a control system 200.

[0048] The control system 200 serves as the control center and can control the operation of the molding system 110, the powder spreading system 120, the powder return system 130, the brush motion system 150, and the optical imaging monitoring system 160.

[0049] It should be understood that the aforementioned forming system 110, powder return system 130, and laser optical path system 140 can be designed using existing selective laser melting (SLM) additive manufacturing equipment.

[0050] Combination Figure 1 As shown, the forming chamber 100 constitutes the printing operation space of the laser selective melting equipment. Its interior is usually configured to achieve a protective gas environment and appropriate oxygen content and pressure through a matching atmosphere achieving mechanism.

[0051] The molding system 110 has a printing substrate located within the molding chamber 100. As is typical in prior art designs, the molding system 110 is generally equipped with a molding cylinder capable of vertical movement, which drives the printing substrate to move vertically. Corresponding to each layer of the printing process, the molding cylinder drives the printing substrate downwards a predetermined distance.

[0052] The powder spreading system 120 is located inside the molding chamber 100 and on one side of the molding system 110, such as... Figure 1As shown, it is located on its right side. The powder spreading system 120 is designed with multiple switchable scrapers 10, which, when switched to a working position, can move along the powder spreading direction to spread metal powder from the powder feeder onto the surface of the printing substrate. As is typical in prior art designs, the powder spreading system 120 is usually equipped with a vertically movable powder feeding cylinder. Corresponding to each layer of the printing process, the powder feeding cylinder moves upward a predetermined distance and spreads powder using the scrapers.

[0053] In an embodiment of the present invention, a guide rail groove is provided on the side of the molding chamber 100, and the powder spreading system 120 can be configured with a motor motion control mechanism, such as a DC or AC motor, to drive the powder spreading system 120 to spread powder. Figure 1 As shown, the metal powder is spread onto the printing substrate of the molding system 110 by the movement of the scraper 10 from right to left, and continues to move to the left to recover the powder to the powder recovery system 130. As is typical in prior art, the powder recovery system 130 is usually equipped with a powder recovery cylinder.

[0054] like Figure 1 As shown, the powder recovery system 130 is located inside the molding chamber 100 and on the other side of the molding system 1100, and is used to recover powder.

[0055] The laser optical path system 140 is positioned above the molding chamber 100 and is used to melt and lay metal powder on the printing substrate of the molding system 110 according to a preset printing program.

[0056] Combination Figure 1 In the embodiment shown, the powder spreading device of the present invention is further provided with a brush motion system 150, which is disposed inside the forming chamber 100 and can be driven to reciprocate on the upper surface of the powder return system 130, brushing away the powder adhering to the lower surface of the scraper 10 during the reciprocating motion.

[0057] As an optional embodiment, the brush motion system 150 has a motion mechanism (e.g., driven by a motor) and a brush driven thereby, the brush being able to reciprocate on the upper surface of the powder return system 130, the running direction being the powder spreading motion direction and its return direction, thereby brushing away powder on the scraper.

[0058] As an optional embodiment, the control system 200 controls the brush motion system 150 to periodically clean the scraper 10 according to a preset number of powder layers.

[0059] The system pre-configures a scraper cleaning cycle. After the powder spreading system 120 completes the preset number of powder layers, printing is paused, and the brush motion system 150 is controlled to reciprocate on the upper surface of the powder return system 130 to scrape off the powder adhering to the lower surface of the scraper 10 and perform periodic cleaning of the scraper 10.

[0060] In an embodiment of the invention, printing is paused after every 10 layers of powder to perform periodic cleaning of the squeegee. During the brush's movement, it can be driven to reciprocate 1-2 times, or configured as needed, thereby reducing powder adhering to the lower surface of the squeegee and improving powder spreading quality.

[0061] Combination Figure 1 The optical imaging monitoring system 160 includes at least one CCD camera positioned toward the molding system 110 for capturing images of each layer of powder. The CCD camera may be located inside the molding chamber 100 or outside the molding chamber 100 through a window.

[0062] In an embodiment of the present invention, a CCD camera is mounted on the upper chamber of the molding system and can be embedded to monitor the powder spreading on the printing plane and the reference plane in real time, as well as the forming quality of the printed parts.

[0063] The control system 200 is configured to control the reciprocating motion of the brush motion system 150 to clean the powder adhering to the scraper 10 and to automatically switch the scraper 10 based on the quality comparison results of the powder spreading image.

[0064] In an embodiment of the present invention, the control system 200, based on fine or deep marks present in the toner-laying image, controls to pause printing and controls the brush motion system 150 to clean the scraper. The aforementioned fine marks refer to toner-laying traces with a width exceeding a preset value, and the deep marks refer to toner-laying traces with a depth or height exceeding a preset value.

[0065] In embodiments of the present invention, the powder-spreading image can be identified and processed by image recognition algorithms, such as edge detection and size measurement algorithms, to determine the size of fine and deep marks.

[0066] The control system 200 controls the brush motion system 150 to move based on the fine or deep marks present in the toner-spreading image. After cleaning the scraper, it controls the re-spreading of toner and compares the toner-spreading image. If the fine or deep marks still exist, it controls the replacement of the scraper; otherwise, it continues printing using the current scraper.

[0067] Combination Figure 1 As shown, the powder spreading device, as an example, also includes:

[0068] The reference plane 190, located between the forming system and the powder return system, serves as a reference plane for leveling the scraper 10.

[0069] During the printing process, as the toner spreading system 120 spreads toner through its scraper 10 and moves toward the toner return system 130, the reference plane 190 is covered with toner. The toner accumulation at the reference plane 190 position is photographed by a CCD camera to determine the wear of the scraper.

[0070] The control system 200 is configured to control the powder spreading system 120 to switch the scraper when the powder spreading area in the region exceeds a set threshold.

[0071] Therefore, in the example of the present invention, the reference plane is located in the middle of the forming system and the powder return system. On the one hand, the scraper can be leveled by using this position as a reference plane. On the other hand, the wear of the scraper can be judged by observing the powder accumulation at this position during the printing process.

[0072] For example, during the printing process, powder is spread on reference plane 2, and the area exceeds a set threshold, such as 30-50 mm. 2 If the threshold range is reached, it is determined that the scraper is severely worn and the forming accuracy of the parts cannot be guaranteed. The powder spreading system is then controlled to switch the scraper at 120.

[0073] Combination Figure 1 , 2 As shown, the powder spreading system 120 includes a slider 6, a motor 7, a rotary motion shaft 8, a scraper clamp 9, a scraper 10, a scraper holder 11, and a cantilever beam 12.

[0074] The scraper holder 11 is cylindrical and is horizontally installed inside the cantilever beam 12.

[0075] The motor 7 is fixed on the cantilever beam 12 and connected to the cylindrical scraper holder 11 via the rotary motion shaft 8, for driving the cylindrical scraper holder 11 to transmit power along its central axis; the output shaft of the motor 7, the rotary motion shaft 8 and the scraper holder 11 are coaxially mounted.

[0076] Multiple scrapers 10 are mounted on the surface of the scraper holder 11 by their respective scraper clamps 9, and each scraper 10 is mounted along the length of the scraper holder 11.

[0077] The slider 6 is fixed to the outside of the cantilever beam 12 and connected to the powder spreading motion control system installed inside the forming chamber 100. Specifically, through the cooperation of the guide rail and the slider, the slider 6 is driven to move, thereby causing the cantilever beam 12 and the scraper 10 to move synchronously, achieving powder spreading. In an embodiment of the invention, two sets of sliders are installed at one end of the cantilever beam. The powder spreading operation is completed by the linear movement of the sliders on the guide rail.

[0078] The aforementioned control system 200 can control the movement of the motor 7 to control the rotation of the scraper holder 11, thereby switching the scraper 10. This allows the scraper to be switched freely during the printing process according to the condition of the printed parts and the wear of the scraper, ensuring the uniformity of powder spreading and printing quality.

[0079] In embodiments of the present invention, the plurality of scrapers 10 include soft scrapers made of rubber and hard scrapers made of ceramic or high-speed steel.

[0080] Combination Figure 2 As shown, the scraper clamp is mounted on the scraper holder to fix the scraper and to adjust the parallelism and height distance between the scraper and the reference plane.

[0081] {Powder spreading method for laser selective melting equipment}

[0082] In conjunction with the powder spreading device for laser selective melting equipment described above, the powder spreading method for laser selective melting equipment according to an embodiment of the present invention includes the following steps:

[0083] During the printing process, the CCD camera captures images of each layer of powder to obtain powder-spreading images;

[0084] Identify whether there are fine or deep scratches in the powder-spreading image:

[0085] If fine or deep scratches are present, the system pauses printing and controls the brush motion system 150 to reciprocate on the upper surface of the toner return system 130 to clean the toner stuck to the bottom of the scraper. After cleaning, the system re-spreads toner and takes a toner-spreading image, and compares the toner-spreading image again. If fine or deep scratches still exist, the system replaces the scraper; otherwise, the system continues printing using the currently cleaned scraper.

[0086] In a further embodiment, the powder spreading method further includes the following steps:

[0087] A reference plane 190 is set at the midpoint between the forming system and the powder return system, serving as a reference plane for leveling the scraper 10;

[0088] During the printing process, as the powder spreading system 120 spreads powder through its scraper 10 and moves toward the powder return system 130, the reference plane 190 is covered with powder. The powder accumulation at the reference plane 190 position is photographed by the CCD camera to determine the wear of the scraper.

[0089] The control system 200 is configured to control the powder spreading system 120 to switch the scraper when the powder spreading area in the region exceeds a set threshold.

[0090] As an optional embodiment, during the printing process, the control system 200's operation control process for the toner spreading system 120, toner return system 130, laser optical path system 140, brush motion system 150, and optical imaging monitoring system 160 includes:

[0091] Monitoring the printed surface: The CCD camera takes pictures of each layer of powder after it is laid, saves the pictures, uploads them to the server, and the software algorithm on the server can compare the powder quality and then send the instructions back to the control system 200.

[0092] Squeegee cleaning: During normal printing, the brush motion system 150 is set to clean the squeegee 10 every 10 layers. When the toner quality captured by the CCD camera is compared with the data on the server software and it is determined to exceed the set threshold (e.g., fine or deep marks appear on the toner surface), printing is paused, and the brush motion system 150 is controlled to move on the upper surface of the toner return system 130 to clean the squeegee 10. After cleaning, toner is re-spread and a photo is taken for comparison. If the toner quality is qualified, printing continues. Otherwise, the control system controls the toner spreading mechanism to replace the squeegee 10. After the squeegee 10 replacement process is completed, printing continues.

[0093] Scraper replacement: In the powder spreading system, the scraper holder 11 is rotated by the motor to replace the worn scraper 10 and printing continues. When the wall thickness of the parts exceeds 2mm, the control system issues an instruction to replace the high-speed steel hard scraper. When the wall thickness is less than 2mm, the rubber soft scraper is replaced to ensure the flatness and accuracy of the surface and reduce the deformation of the parts.

[0094] Monitoring the reference plane: During the printing process, the CCD camera monitors the toner accumulation on a reference plane at 190°, saves the data, and uploads it to the server for comparison. The server determines whether the toner accumulation area exceeds a preset threshold, for example, a threshold set at 50mm. 2 The system determines that the scraper is severely worn and cannot guarantee the forming accuracy of the parts, and feeds the result back to the control system 200.

[0095] Scraper replacement: The control system 200 controls the powder spreading system to replace the scraper. The scraper holder 11 is driven by the motor to rotate and replace the scraper with an unworn scraper 10 before printing continues, thus ensuring the forming quality of the parts.

[0096] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A powder spreading device for laser selective melting equipment, characterized in that, include: Molding compartment (100); The molding system (110) has a printing substrate located in the molding chamber; The powder spreading system (120) is disposed inside the forming chamber (100) and located on one side of the forming system (110). The powder spreading system (120) has a scraper holder (11) and a plurality of interchangeable scrapers (10) mounted thereon. When any scraper (10) is switched to the working position, it can move along the powder spreading direction to spread metal powder from the powder feeder on the surface of the printing substrate. A powder recovery system (130) is provided inside the molding chamber (100) and on the other side of the molding system (110) for recovering powder; A laser optical path system (140) is positioned above the molding chamber (100) and is used to melt the metal powder laid on the printing substrate of the molding system (110) according to a preset printing program. The brush motion system (150) is located inside the molding chamber (100) and can be driven to reciprocate on the upper surface of the powder return system (130) to brush away the sticky powder on the lower surface of the scraper (10) during the reciprocating motion. The optical imaging monitoring system (160) includes at least one CCD camera positioned toward the molding system (110) for capturing powder images of each layer of powder; The control system (200) is configured to control the reciprocating motion of the brush motion system (150) to clean the powder adhering to the scraper (10) and automatically switch the scraper (10) based on the quality comparison results of the powder spreading image, specifically including: During the printing process, the CCD camera captures images of each layer of powder to obtain powder-spreading images; Identify whether there are fine or deep scratches in the powder-spreading image: If fine or deep scratches are present, the printing is paused and the brush motion system (150) is reciprocated on the surface of the toner return system (130) to clean the toner stuck to the bottom of the scraper. After cleaning, the toner is re-spread and a toner-spreading image is taken and compared again. If fine or deep scratches are still present, the scraper is replaced; otherwise, the currently cleaned scraper is used to continue printing.

2. The powder spreading device for laser selective melting equipment according to claim 1, characterized in that, The control system (200) is configured to control the brush motion system (150) to periodically clean the scraper (10) according to a preset number of powder layers.

3. The powder spreading device for laser selective melting equipment according to claim 1, characterized in that, The fine marks refer to powder marks whose width exceeds a preset value, and the deep marks refer to powder marks whose depth or height exceeds a preset value.

4. The powder spreading device for laser selective melting equipment according to claim 1, characterized in that, The powder spreading device further includes: The reference plane (190) located between the forming system and the powder return system is used as a reference plane for leveling the scraper (10); During the printing process, as the powder spreading system (120) spreads powder through its scraper (10) and moves toward the powder return system (130), the reference plane (190) is covered with powder. The powder accumulation at the location of the reference plane (190) is photographed by a CCD camera to determine the wear of the scraper. The control system (200) is configured to control the powder spreading system (120) to switch the scraper when the powder spreading area in the region exceeds a set threshold.

5. The powder spreading device for laser selective melting equipment according to any one of claims 1-4, characterized in that, The powder spreading system (120) includes a slider (6), a motor (7), a rotary motion shaft (8), a scraper clamp (9), a scraper (10), a scraper holder (11), and a cantilever beam (12). The scraper holder (11) is cylindrical and is horizontally installed inside the cantilever beam (12); The motor (7) is fixed on the cantilever beam (12) and connected to the cylindrical scraper holder (11) via the rotary motion shaft (8) for driving the cylindrical scraper holder (11) to transmit power along its central axis; the output shaft of the motor (7), the rotary motion shaft (8) and the scraper holder (11) are coaxially mounted. Multiple scrapers (10) are mounted on the surface of the scraper holder (11) by their respective scraper clamps (9), and each scraper (10) is mounted along the length of the scraper holder (11); The slider (6) is fixed on the outside of the cantilever beam (12) and connected to the powder spreading motion control system set in the molding chamber (100) to drive the slider (6) to move, so that the cantilever beam (12) and the scraper (10) move synchronously to achieve powder spreading; The control system (200) can control the movement of the motor (7) to control the rotation of the scraper holder (11), thereby switching the scraper (10).

6. The powder spreading device for laser selective melting equipment according to claim 5, characterized in that, The plurality of scrapers (10) include soft scrapers made of rubber and hard scrapers made of ceramic or high-speed steel.

7. A method for spreading powder in a laser selective melting apparatus according to any one of claims 1-6, characterized in that, The powder spreading method includes the following steps: During the printing process, the CCD camera captures images of each layer of powder to obtain powder-spreading images; Identify whether there are fine or deep scratches in the powder-spreading image: If fine or deep scratches are present, the printing is paused and the brush motion system (150) is reciprocated on the surface of the toner return system (130) to clean the toner stuck to the bottom of the scraper. After cleaning, the toner is re-spread and a toner-spreading image is taken and compared again. If fine or deep scratches are still present, the scraper is replaced; otherwise, the currently cleaned scraper is used to continue printing.

8. The powder spreading method for laser selective melting equipment according to claim 7, characterized in that, The powder spreading method also includes the following steps: A reference plane (190) is set at the middle position between the forming system and the powder return system, which is used as a reference plane for leveling the scraper (10); During the printing process, as the powder spreading system (120) spreads powder through its scraper (10) and moves toward the powder return system (130), the reference plane (190) is covered with powder. The powder accumulation at the location of the reference plane (190) is photographed by the CCD camera to determine the wear of the scraper. The control system (200) is configured to control the powder spreading system (120) to switch the scraper when the powder spreading area in the region exceeds a set threshold.

9. The powder spreading method for laser selective melting equipment according to claim 7, characterized in that, The powder spreading method also includes the following steps: The scraper cleaning cycle is pre-configured. After the powder spreading system (120) completes the preset number of powder spreading layers, printing is paused, and the brush motion system (150) is controlled to reciprocate on the upper surface of the powder return system (130) to scrape off the powder adhering to the lower surface of the scraper (10) and perform periodic cleaning of the scraper (10).

Images