Scraper mechanism and 3D printing powder spreading method

Abstract

The invention relates to the technical field of additive manufacturing, in particular to a scraper mechanism and a 3D printing powder laying method. The scraper mechanism comprises a support, a scraper assembly, a grinding assembly and a detection assembly. The support is used for moving in the powder laying direction. The detection assembly is used for acquiring information of a flat surface of a current printing position and a printing surface bulge; the polishing assembly is used for polishing the printing face protrusions. And the scraper assembly is used for spreading powder on the leveled printing position. The 3D printing powder laying method is based on the scraper mechanism and comprises the steps that the support is controlled to move in the powder laying direction; controlling a detection assembly to detect whether a printing surface bulge exists on the flat surface or not; controlling the detection assembly to measure the height of a printing surface bulge when the printing surface bulge exists on the flat surface; the polishing assembly is controlled to polish the printing face protrusion when the height of the printing face protrusion is larger than the preset height; and controlling the scraper assembly to spread powder. According to the scraper mechanism and the 3D printing powder laying method, protrusions on the printing face can be detected and polished before powder laying, and the powder laying effect is good.

Description

Technical Field

[0001] This application relates to the field of additive manufacturing technology, specifically to a scraper mechanism and a 3D printing powder spreading method. Background Technology

[0002] Selective laser melting (SLM) technology, as one of the important processes in metal 3D printing, has significant advantages in manufacturing complex structural parts. However, in actual printing processes, factors such as thermal stress accumulation, uneven powder spreading, or fluctuations in process parameters often lead to warping or localized protrusions in the cured layer. If these defects are not addressed in time, they will affect the quality of subsequent powder spreading and may even cause squeegee collisions, printing interruptions, or the scrapping of the entire part.

[0003] Traditional SLM equipment typically requires pausing the printing process, opening the forming chamber door, and manually sanding the raised areas when encountering protrusions on the printing surface. This method is not only inefficient and reliant on operator experience, but also struggles to guarantee a uniform and smooth finish, easily leading to secondary damage or subsequent printing failures. Furthermore, the human interference and changes in the chamber environment introduced during manual processing can adversely affect the forming quality and process stability. Summary of the Invention

[0004] In view of the above, it is necessary to propose a scraper mechanism and a 3D printing powder spreading method, which can detect and polish the protrusions on the printing surface before powder spreading, resulting in good powder spreading effect.

[0005] This application provides a scraper mechanism, including a support and a scraper assembly, a polishing assembly, and a detection assembly sequentially arranged on the support along the powder spreading direction; wherein, the support is used to move along the powder spreading direction under the drive of an external driving device; the detection assembly is used to acquire information on the flat surface of the current printing position and the printing surface protrusion above the flat surface, and is used to detect the height of the printing surface protrusion; the polishing assembly is used to polish the printing surface protrusion to be flush with the flat surface or to a preset height; the scraper assembly is used to spread powder on the polished printing surface.

[0006] In some embodiments, the detection component includes a transmitter and a receiver. The transmitter is connected to a bracket and is used to emit a laser plane toward the flat surface in a direction perpendicular to the flat surface. The receiver is connected to the bracket and is used to receive the reflected light after the laser plane illuminates the flat surface or the printing surface protrusion, so as to detect whether there is a printing surface protrusion on the flat surface and to detect the height and volume of the printing surface protrusion.

[0007] In some embodiments, the height of the test point on the printed surface protrusion satisfies the following relationship: H=L / sinθ; where the test point is any position where the printed surface protrudes from the flat surface, the line where the laser plane intersects the flat surface is l, θ is the angle between the reflection plane of the receiver receiving the line l and the laser plane, L is the minimum distance between the test point and the reflection plane of the receiver receiving the line l, and H is the height of the test point.

[0008] In some embodiments, the volume of the printed surface protrusion satisfies the following relationship: V=∑d s ×d y d s =∑d x ×d h The rotational speed of the grinding component satisfies the following formula: S = S0 × (V / V0); the travel speed of the grinding component satisfies the following formula: F = F0 ÷ (V / V0); where V is the volume of the printing surface protrusion, d y When the printing surface protrusion is divided into multiple slices along the powder spreading direction, d represents the width of each slice along the powder spreading direction. s The area of ​​each slice, d x The length of each segment when each slice is divided into multiple segments along the horizontal direction, d h For each segment, V0 is the volume of the standard printed surface protrusion, S0 is the rotational speed of the grinding component when the volume of the standard printed surface protrusion V0 is reached, F0 is the travel speed of the grinding component when the volume of the standard printed surface protrusion V0 is reached, S is the actual rotational speed of the grinding component, and F is the actual travel speed of the grinding component.

[0009] In some embodiments, the polishing assembly includes a polishing drive, a polishing disc, and a plurality of polishing components. The polishing drive is connected to a bracket, the polishing disc is rotatably connected to the bracket and driven by the polishing drive. The polishing drive is used to drive the polishing disc to rotate, and the plurality of polishing components are all connected to the polishing disc and are used to polish the protrusions on the printed surface.

[0010] In some embodiments, the grinding disc includes a connecting portion and a mounting portion connected together. The connecting portion is connected to a bracket and has a connecting hole, and the mounting portion has a cavity communicating with the connecting hole. The connecting portion is used to connect to an external air extraction device to extract grinding waste from the cavity through the connecting hole.

[0011] In some embodiments, a plurality of grinding elements are disposed on the side of the mounting portion away from the communicating portion, and each grinding element is arc-shaped, with the concave side of each grinding element facing the rotation direction of the mounting portion.

[0012] In some embodiments, the grinding assembly further includes a lifting drive, which is connected to the bracket. The grinding disc is connected to the bracket via the lifting drive, and the lifting drive is used to drive the grinding disc to move closer to or away from the bracket.

[0013] In some embodiments, the scraper mechanism includes multiple sets of the grinding components and multiple sets of the detection components. The multiple sets of grinding components and multiple sets of the detection components are arranged sequentially along the length direction of the scraper component, and the grinding range of the grinding element of the multiple grinding components covers the powder spreading range of the scraper component.

[0014] The aforementioned scraper mechanism includes a scraper assembly, a grinding assembly, and a detection assembly, all sequentially fixed to the same support along the powder spreading direction. When the support moves along the powder spreading direction under the drive of an external drive device, the detection assembly, grinding assembly, and scraper assembly move synchronously with the support. Before the scraper assembly spreads powder, the detection assembly can detect the already printed cured layer to obtain information on the flatness of the current printing position and any protrusions on the printed surface above the flatness, i.e., to detect whether there are any protrusions on the cured layer. When the detection assembly detects a protrusion on the cured layer, the grinding assembly, upon moving to the protrusion's position, grinds the protrusion to eliminate it, and the scraper assembly then spreads powder. Through the cooperation of the detection assembly, grinding assembly, and scraper assembly, the aforementioned scraper mechanism can effectively eliminate the impact of protrusions on the powder spreading process, effectively improving the powder spreading effect.

[0015] This application also provides a 3D printing powder spreading method. Based on the scraper mechanism of any of the above embodiments, the powder spreading method includes the following steps: Control the support to move along the powder spreading direction; The control and detection components detect whether there are any printing surface protrusions on the flat surface; When the control detection component has a printing surface protrusion on a flat surface, it measures the height of the printing surface protrusion. The control unit grinds the printing surface protrusions when the height of the protrusions on the printing surface is greater than the preset height, and the preset height is less than the powder thickness. Control the scraper assembly to spread the powder.

[0016] The powder spreading method described above has at least the same advantages as the scraper mechanism described in any of the above embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the scraper mechanism provided in an embodiment of this application.

[0018] Figure 2 for Figure 1 The scraper mechanism shown is a cross-sectional view along the II-II direction.

[0019] Figure 3 for Figure 1 The scraper mechanism shown is a cross-sectional view along the III-III direction.

[0020] Figure 4 for Figure 1 The diagram shows the structure of the scraper mechanism when the emitter illuminates the raised printing surface.

[0021] Figure 5 for Figure 2 The diagram shows the structure of the detection component of the scraper mechanism when detecting a protrusion on the printed surface.

[0022] Figure 6 for Figure 4 The diagram shows the structure when the printed surface is divided into multiple slices by raised sections.

[0023] Figure 7 for Figure 6 The diagram shows the structure of the raised slice on the printed surface.

[0024] Figure 8 for Figure 1 The diagram shows another angle of the grinding disc of the scraper mechanism.

[0025] Figure 9 A flowchart of the 3D printing powder spreading method provided in the embodiments of this application.

[0026] Explanation of main component symbols: scraper mechanism 100, bracket 10, scraper assembly 20, powder adding tube 21, scraper 22, grinding assembly 30, grinding drive 31, grinding disc 32, connecting part 321, connecting hole 3211, mounting part 322, cavity 3221, grinding part 33, lifting drive 34, detection assembly 40, transmitter 41, laser plane a, receiver 42, reflecting plane b, flat surface 200, printing surface protrusion 201. Detailed Implementation

[0027] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0028] In the description of this application, it should be understood that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, it should be noted that "a plurality of" means two or more, unless otherwise explicitly specified.

[0029] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a connection that allows communication between the two components; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0030] The following will describe some embodiments of this application in detail with reference to the accompanying drawings. To facilitate understanding and explanation of the embodiments of this application, a three-dimensional coordinate system is established in some of the drawings, with the X-axis direction being the powder spreading direction, the Y-axis direction being the extension direction of the scraper 22 described below, and the Z-axis direction being the vertical direction. The X-axis, Y-axis, and Z-axis directions are perpendicular to each other.

[0031] Please see Figure 1 , Figure 2 and Figure 3 This application provides a scraper mechanism 100, applied to a 3D printing device (not shown), used for spreading powder during 3D printing. For ease of understanding, the 3D printing process is briefly described below: During printing, the printing device first spreads a layer of powder on the printing platform, and then emits light through a laser or other means according to preset parameters to solidify the powder layer at preset positions, forming a solidified layer. The upper surface of the solidified layer is the flat surface 200. Then, another layer of powder is spread on the solidified layer and solidified again until the desired structure is printed. In actual printing, due to factors such as thermal stress accumulation, uneven powder spreading, or fluctuations in process parameters, the flat surface 200 on the solidified layer often warps or locally protrudes, thus forming a printing surface protrusion 201 (see [link to relevant documentation]). Figure 4 The raised area 201 on the printing surface can affect the uniformity of powder distribution on the cured layer, thus affecting print quality.

[0032] The scraper mechanism 100 includes a support 10 and a scraper assembly 20, a grinding assembly 30 and a detection assembly 40 arranged sequentially on the support 10 along the powder spreading direction.

[0033] The bracket 10 is used to move along the powder spreading direction under the drive of the external drive device. The detection component 40 is used to obtain information about the flat surface 200 at the current printing position and the printing surface protrusion 201 that is higher than the flat surface 200, and to detect the height of the printing surface protrusion 201. The polishing component 30 is used to polish the printing surface protrusion 201 to be flush with the flat surface 200 or to a preset height. The scraper component 20 is used to spread powder on the polished printing surface.

[0034] The external drive device can be a drive structure in the 3D printing equipment (not shown). When spreading powder, the external drive device drives the support 10 to move along the powder spreading direction, thereby driving the detection component 40, the grinding component 30 and the scraper component 20 to move synchronously.

[0035] The grinding component 30 is used to grind the printing surface protrusions 201. It can be understood that the first layer of powder is laid on the printing platform; therefore, during the laying of the first layer of powder, the detection component 40 and the grinding component 30 do not need to operate, and only the scraper component 20 is needed for powder spreading. When powder is laid on the cured layer, the detection component 40, as it moves with the support 10, detects the flat surface 200 of the cured layer to check for printing surface protrusions 201. When the detection component 40 detects a printing surface protrusion 201 on the flat surface 200, the grinding component 30 operates to grind the printing surface protrusion 201 as it passes over it, thus eliminating the protrusion. After the grinding component 30 grinds the printing surface protrusion 201, the scraper component 20 evenly spreads powder on the cured layer, thus completing the powder spreading operation.

[0036] In some embodiments, the scraper assembly 20 includes a powder feeding tube 21 and a scraper 22 connected to the bracket 10. It is understood that the powder feeding tube 21 is located on the side of the scraper 22 closest to the grinding assembly 30. In actual operation, the powder feeding tube 21 is connected to an external powder supply device (not shown) to provide powder. As the scraper 22 moves along the powder spreading direction, it spreads the powder evenly, thus completing the powder spreading process.

[0037] The scraper mechanism 100 provided in this application embodiment includes a scraper assembly 20, a polishing assembly 30, and a detection assembly 40, which are sequentially fixed on the same support 10 along the powder spreading direction. When the support 10 moves along the powder spreading direction under the drive of an external drive device, the detection assembly 40, the polishing assembly 30, and the scraper assembly 20 move synchronously with the support 10. Before the scraper assembly 20 spreads powder, the detection assembly 40 can detect the already printed cured layer to obtain information on the flat surface 200 at the current printing position and the printing surface protrusion 201 that is higher than the flat surface 200, i.e., to detect whether there is a printing surface protrusion 201 on the cured layer. When the detection assembly 40 detects a printing surface protrusion 201 on the cured layer, the polishing assembly 30 polishes the printing surface protrusion 201 when it moves to the position of the printing surface protrusion 201 to eliminate the printing surface protrusion 201, and then the scraper assembly 20 spreads powder. The scraper mechanism 100 provided in this application embodiment, through the cooperation of the detection component 40, the polishing component 30 and the scraper component 20, can effectively eliminate the influence of the printing surface protrusion 201 on the powder spreading process and effectively improve the powder spreading effect.

[0038] In some embodiments, see Figure 2 , Figure 4 and Figure 5 The detection component 40 includes a transmitter 41 and a receiver 42. The transmitter 41 is connected to the bracket 10 and is used to emit a laser plane a toward the flat surface 200 in a direction perpendicular to the flat surface 200. The receiver 42 is connected to the bracket 10 and is disposed on the side of the transmitter 41 near the polishing component 30. The receiver 42 is used to receive the reflected light after the laser plane a illuminates the flat surface 200 or the printed surface protrusion 201, so as to detect whether the flat surface 200 has a printed surface protrusion 201 and to detect the height and volume of the printed surface protrusion 201.

[0039] The transmitter 41 can be a line laser, etc., and the receiver 42 can be a CCD camera, etc. The transmitter 41 emits a laser plane a in a direction perpendicular to the flat surface 200. The laser plane a intersects with the flat surface 200 to form a line and undergoes diffuse reflection. The receiver 42 can acquire the light rays at the intersection of the laser plane a and the flat surface 200, and thus identify the image information at the intersection of the laser plane a and the flat surface 200. When there is a printing surface protrusion 201 on the flat surface 200, the intersection of the laser plane a and the printing surface protrusion 201 is not a straight line. For example, if the printing surface protrusion 201 is hemispherical, the intersection line formed by the laser plane a and the printing surface protrusion 201 is an arc. The receiver 42 can determine whether there is a printing surface protrusion 201 on the flat surface 200 based on the image information of the intersection of the laser plane a and the flat surface 200. When there is a printing surface protrusion 201 on the flat surface 200, the detection component 40 can transmit the position information of the printing surface protrusion 201 to the polishing component 30 so that the polishing component 30 can perform polishing processing when passing the printing surface protrusion 201.

[0040] In some embodiments, see Figure 2 , Figure 4 and Figure 5 The height of the test point of the printing surface protrusion 201 satisfies the following relationship: H=L / sinθ; where the test point is any position where the printing surface protrusion 201 protrudes from the flat surface 200, the line where the laser plane a intersects with the flat surface 200 is l, θ is the angle between the reflection plane b of the receiver 42 receiving the line l and the laser plane a, L is the minimum distance between the test point and the reflection plane b of the receiver 42 receiving the line l, and H is the height of the test point.

[0041] After the transmitter 41 is installed on the bracket 10, its position is fixed. The position where the laser plane a emitted by the transmitter 41 intersects with the flat surface 200 is fixed relative to the scraper mechanism 100, that is, the position of the straight line l is fixed relative to the scraper mechanism 100. After the receiver 42 is installed on the bracket 10, its position and angle are fixed. The angle between the reflection plane b of the receiver 42 receiving the straight line l and the laser plane a is fixed, that is, θ is a constant value after the receiver 42 is installed.

[0042] It is understandable that when there is a printing surface protrusion 201 on the flat surface 200, the intersection line formed by the laser plane a emitted by the transmitter 41 and the printing surface protrusion 201 changes and is no longer a straight line, and it shifts away from the reflection plane b of the line l received by the receiver 42. The minimum distance L between the test point and the reflection plane b of the line l received by the receiver 42 is the distance between the test point and the line l from the perspective of the receiver 42. Therefore, by receiving the image information of the intersection of the laser plane a with the flat surface 200 and the printing surface protrusion 201, the minimum distance L between the test point and the reflection plane b of the line l received by the receiver 42 can be directly obtained, and the height of the corresponding test point can be calculated according to the Pythagorean theorem.

[0043] Taking the highest point of the printed surface protrusion 201 as an example, when the laser plane a emitted by the transmitter 41 scans to the highest point of the printed surface protrusion 201, the receiver 42 obtains the minimum distance L between the highest point and the reflection plane b of the receiving line l, and calculates the height H of the highest point. In the actual printing process, the powder layer has a predetermined thickness. Therefore, if the height of the highest point of the printed surface protrusion 201 is not greater than the predetermined thickness of the powder layer, the printed surface protrusion 201 does not need to be polished, reducing polishing time and improving powder spreading efficiency. Furthermore, when the transmitter 41 and receiver 42 cooperate to scan the printed surface protrusion 201, if the height of a certain position of the printed surface protrusion 201 is detected to be greater than the powder spreading thickness, the polishing component 30 can be activated to polish the printed surface protrusion 201. Of course, it can also be set to drive the polishing component 30 to polish as soon as the printed surface protrusion 201 is detected, so as to eliminate all the printed surface protrusions 201 before powder spreading.

[0044] In some embodiments, see Figure 5 , Figure 6 and Figure 7 The volume of the printed surface protrusion 201 satisfies the following relationship: V=∑d s ×d y d s =∑d x ×d h The rotational speed of the grinding component 30 satisfies the following formula: S = S0 × (V / V0); the travel speed of the grinding component 30 satisfies the following formula: F = F0 ÷ (V / V0). Where V is the volume of the printing surface protrusion 201, and d... y When the printing surface protrusion 201 is divided into multiple slices along the powder spreading direction, the width d of each slice along the powder spreading direction is... s The area of ​​each slice, d x The length of each segment when each slice is divided into multiple segments along the horizontal direction, d h For each segment, V0 is the volume of the standard printing surface protrusion 201, S0 is the rotational speed of the grinding component 30 when the volume of the standard printing surface protrusion 201 is V0, F0 is the travel speed of the grinding component 30 when the volume of the standard printing surface protrusion 201 is V0, S is the actual rotational speed of the grinding component 30, and F is the actual travel speed of the grinding component 30.

[0045] Please see also Figure 2 The width of the printing surface protrusion 201 along the powder spreading direction can be obtained from the relationship between the speed and time when the detection component 40 scans and detects the printing surface protrusion 201. Then, the width d of each slice along the powder spreading direction when the printing surface protrusion 201 is divided into multiple slices along the powder spreading direction can be calculated. yThe detection component 40 can directly measure the length of each slice in the X-axis direction during the detection of the printed surface protrusion 201, and thus determine the length d of each segment. x The height of each segment can be calculated using the height formula, thus obtaining the height d of each segment. h The volume of the printing surface protrusion 201 can be calculated by substituting it into the volume formula. Based on the volume of the printing surface protrusion 201, the required rotational speed and travel speed for each printing surface protrusion 201 can be obtained by substituting the rotational speed formula and travel speed formula of the polishing component 30.

[0046] V0 represents the volume of the standard printing surface protrusion 201. This volume is manually set and can be adjusted based on the volume of printing surface protrusions 201 commonly encountered in actual production. V0 is used to calibrate the standard rotational speed S0 and standard travel speed F0; specific values ​​are not limited here. It can be understood that when the volume of the printing surface protrusion 201 is the standard volume V0, the printing surface protrusion 201 with a volume of V0 can be eliminated by setting the rotational speed of the polishing component 30 to S0 and the travel speed to F0. In actual production, the rotational speed S0 and travel speed F0 are related to the material of the curing layer and the material of the polishing component 30. Under the same standard volume V0, different curing layer materials or different materials of the polishing component 30 will affect the rotational speed S0 and travel speed F0. Therefore, the rotational speed S0 and travel speed F0 need to be tested based on the actual production materials; their specific values ​​are not limited here.

[0047] The printed surface protrusion 201 is part of the cured layer. Therefore, when sanding the printed surface protrusion 201, a corresponding travel speed needs to be matched. It can be understood that when sanding the printed surface protrusion 201, the travel speed of the scraper mechanism 100 is lower than when only toner needs to be spread. In actual production, if the travel speed of the scraper mechanism 100 is set to a fixed value, larger printed surface protrusions 201 will not be sanded flat, and smaller printed surface protrusions 201 will be over-sanded, affecting the toner spreading speed. Adjusting the printing parameters in real time according to the different sizes of the printed surface protrusions 201 can improve sanding efficiency while ensuring the sanding effect.

[0048] In some embodiments, see Figure 1 , Figure 2 and Figure 8The polishing assembly 30 includes a polishing drive 31, a polishing disc 32, and multiple polishing components 33. The polishing drive 31 is connected to the bracket 10, and the polishing disc 32 is rotatably connected to the bracket 10 and driven by the polishing drive 31. The polishing drive 31 drives the polishing disc 32 to rotate. Multiple polishing components 33 are connected to the side of the polishing disc 32 near the cured layer, and are used to polish the printing surface protrusions 201. The polishing drive 31 can be a rotary motor, etc. A drive gear can be provided at the output end of the polishing drive 31, and a driven gear can be provided at the position opposite to the drive gear on the polishing disc 32. The drive gear and the driven gear mesh, thereby enabling the polishing drive 31 to drive the polishing disc 32 to rotate. Four, six, eight, etc., polishing components 33 can be provided, and the multiple polishing components 33 can be arranged symmetrically around the rotation axis of the polishing disc 32. When the polishing disc 32 passes over the printing surface protrusion 201, multiple polishing parts 33 can perform multiple polishing operations per unit time. Compared with a single polishing part 33 or a reciprocating tool, the material removal rate is significantly higher, and it can quickly and efficiently flatten the large printing surface protrusion 201.

[0049] In some embodiments, see Figure 1 , Figure 2 and Figure 8 The grinding disc 32 includes a connecting portion 321 and a mounting portion 322 connected together. The connecting portion 321 is connected to the support 10 and has a connecting hole 3211. The mounting portion 322 is located at the end of the connecting portion 321 away from the support 10, and the mounting portion 322 has a cavity 3221 communicating with the connecting hole 3211. The connecting portion 321 is used to connect to an external air extraction device (not shown) to extract grinding waste from the cavity 3221 through the connecting hole 3211. The connecting portion 321 can be a tubular structure, and the mounting portion 322 can be a trumpet-shaped structure. It is understood that when the grinding part 33 grinds the printing surface protrusion 201, it will generate debris. The remaining debris has high hardness; if mixed with powder, it will be melted into the part by the laser during subsequent printing, becoming a stress concentration point or internal defect, weakening the compactness and mechanical properties of the part. By designing a cavity 3221 inside the grinding disc 32 and using an external suction device to generate negative pressure, the generated debris and metal slag can be sucked away while the grinding part 33 is grinding the printing surface protrusion 201. This on-demand cleaning mode eliminates the possibility of grinding waste splashing, spilling, or being crushed back into the powder layer, maintaining a clean printing environment and avoiding defects in subsequent printing layers caused by the introduction of impurities.

[0050] In some embodiments, see Figure 1 , Figure 2 and Figure 8Multiple grinding elements 33 are disposed on the side of the mounting portion 322 opposite to the connecting portion 321, and each grinding element 33 is arc-shaped, with its concave side facing the rotation direction of the mounting portion 322. Thus, when the grinding disc 32 rotates in a specified direction, the arc-shaped concave side facing the rotation direction forms a guide channel. Under the action of centrifugal force, the cut debris is guided along the arc-shaped surface of the blade to the central area of ​​the grinding disc 32, thereby corresponding to the position of the connecting hole 3211, facilitating the removal of debris.

[0051] In some embodiments, see Figure 1 , Figure 2 and Figure 5 The polishing assembly 30 also includes a lifting drive 34, which is connected to the bracket 10. The polishing disc 32 is connected to the bracket 10 via the lifting drive 34. The lifting drive 34 is used to drive the polishing disc 32 closer to or further away from the bracket 10. The lifting drive 34 can be a telescopic cylinder, which controls the lifting and lowering of the polishing disc 32. When the detection assembly 40 does not detect a protrusion, the lifting drive 34 can lift the polishing disc 32 to maintain a safe distance from the cured layer, preventing the polishing disc 32 and polishing element 33 from scratching and abrading the flat cured layer when not in operation. This protects the fine surface of the cured layer and reduces the ineffective wear of the polishing element 33. When the detection assembly 40 detects a printing surface protrusion 201, the lifting drive 34 drives the polishing disc 32 to descend, allowing the polishing element 33 to polish the printing surface protrusion 201.

[0052] In some embodiments, see Figure 1 , Figure 3 and Figure 5 The scraper mechanism 100 includes multiple sets of polishing components 30 and multiple sets of detection components 40. These components are arranged sequentially along the length of the scraper assembly 20, and the polishing range of the polishing parts 33 of each polishing component 30 covers the powder-spreading range of the scraper assembly 20. Two, three, or four sets of polishing components 30 and detection components 40 can be provided, sufficient to cover the entire width of the cured layer along the Y-axis. By providing multiple sets of polishing components 30 and detection components 40, they can cooperate to polish each printed surface protrusion 201. Each set of polishing components 30 and detection components 40 operates independently. When only a localized area of ​​the cured layer has a printed surface protrusion 201, the corresponding detection component 40 detects the protrusion, and the corresponding polishing component 30 operates to polish the protrusion 201 in that area, while the polishing components 30 in other areas do not need to operate. This reduces equipment idle time, saves energy, and avoids interference with normal areas.

[0053] The working process of the scraper mechanism 100 provided in this embodiment is roughly as follows: Driven by an external drive device, the scraper mechanism 100 moves along the powder spreading direction. During the movement of the scraper mechanism 100, the detection component 40 works synchronously. Specifically, the transmitter 41 emits a laser plane a towards the surface of the cured layer, and the receiver 42 receives the reflected light. By analyzing the shape of the reflected light, the system can determine in real time whether there is a printing surface protrusion 201 on the printing surface of the current scanning path, and can also calculate the height and volume of the printing surface protrusion 201.

[0054] When the cured layer has a printing surface protrusion 201 and the height of the printing surface protrusion 201 is greater than a preset height, the polishing component 30 corresponding to the detection component 40 operates. The speed at which the external drive device drives the printing mechanism is adjusted according to the volume of the printing surface protrusion 201, and the rotational speed of the polishing drive component 31 driving the polishing disc 32 is also adjusted. During polishing, the lifting drive component 34 drives the polishing disc 32 to descend, allowing the polishing component 33 to polish the printing surface protrusion 201. Simultaneously, the external air extraction device removes polishing debris through the polishing disc 32 to prevent the debris from affecting powder spreading. After polishing is complete, the lifting drive component 34 drives the polishing disc 32 to rise away from the cured layer.

[0055] During the movement of the scraper mechanism 100, the powder feeding pipe 21 of the scraper assembly 20 is connected to the external powder supply device to provide powder. When the scraper 22 moves along the powder spreading direction, it spreads the powder evenly, thereby completing the powder spreading.

[0056] Please see Figure 1 , Figure 2 and Figure 9 This application also provides a 3D printing powder spreading method, based on the scraper mechanism 100 in any of the above embodiments, the powder spreading method includes steps S10 to S50.

[0057] Step S10: Control the support 10 to move along the powder spreading direction.

[0058] Step S20: Control the detection component 40 to detect whether there is a printing surface protrusion 201 on the flat surface 200.

[0059] Step S30: When the detection component 40 has a printing surface protrusion 201 on the flat surface 200, it measures the height of the printing surface protrusion 201.

[0060] Step S40: Control the grinding component 30 to grind the printing surface protrusion 201 when the height of the printing surface protrusion 201 is greater than the preset height, and the preset height is less than the powder thickness.

[0061] Step S50: Control the scraper assembly 20 to spread powder.

[0062] In the above-described powder spreading method, as the support 10 moves along the powder spreading direction, the detection component 40, the polishing component 30, and the scraper component 20 move synchronously with the support 10. Before the scraper component 20 spreads the powder, the detection component 40 detects the already printed cured layer to identify whether there are printing surface protrusions 201 on the flat surface 200. When the detection component 40 detects a printing surface protrusion 201 on the flat surface 200 and the height of the printing surface protrusion 201 is greater than a preset height, the polishing component 30 polishes the printing surface protrusion 201 when it moves to the position of the printing surface protrusion 201 to eliminate the printing surface protrusion 201. The scraper component 20 then spreads the powder. The above-described powder spreading method, through the cooperation of the detection component 40, the polishing component 30, and the scraper component 20, can effectively eliminate the influence of the printing surface protrusion 201 on the powder spreading process and effectively improve the powder spreading effect.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application.

Claims

1. A scraper mechanism, characterized in that, It includes a support frame and a scraper assembly, a grinding assembly, and a detection assembly sequentially arranged along the powder spreading direction on the support frame; wherein, The support is used to move along the powder spreading direction under the drive of an external drive device; The detection component is used to acquire information about the flat surface of the current printing position and the printing surface protrusion above the flat surface, and to detect the height of the printing surface protrusion. The polishing component is used to polish the printing surface protrusions until they are flush with the flat surface or to a preset height; The scraper assembly is used to spread powder on the polished printing surface.

2. The scraper mechanism as described in claim 1, characterized in that, The detection component includes: A transmitter, connected to the bracket, is used to emit a laser plane toward the flat surface in a direction perpendicular to the flat surface; and A receiver, connected to the bracket, is used to receive the reflected light from the laser plane after it illuminates the flat surface or the printing surface protrusion, in order to detect whether the flat surface has the printing surface protrusion and to detect the height and volume of the printing surface protrusion.

3. The scraper mechanism as described in claim 2, characterized in that, The height of the test point on the convex printed surface satisfies the following relationship: H = L / sinθ; Wherein, the point to be measured is any position where the printed surface protrudes from the flat surface, the straight line where the laser plane intersects the flat surface is l, θ is the angle between the reflection plane of the receiver receiving the straight line l and the laser plane, L is the minimum distance between the point to be measured and the reflection plane of the receiver receiving the straight line l, and H is the height of the point to be measured.

4. The scraper mechanism as described in claim 3, characterized in that, The volume of the printed surface protrusion satisfies the following relationship: V=∑d s ×d y ,d s =∑d x ×d h ; The rotational speed of the grinding component satisfies the following relationship: S = S0 × (V / V0); The traveling speed of the grinding component satisfies the following relationship: F = F0 ÷ (V / V0); Where V is the volume of the convex printing surface, and d y When the printing surface protrusion is divided into multiple slices along the powder spreading direction, d represents the width of each slice along the powder spreading direction. s The area of ​​each slice, d x The length d of each segment when each slice is divided into multiple segments along the horizontal direction. h For each segment, V0 is the volume of the standard printed surface protrusion, S0 is the rotational speed of the polishing component when the volume V0 of the standard printed surface protrusion is given, F0 is the travel speed of the polishing component when the volume V0 of the standard printed surface protrusion is given, S is the actual rotational speed of the polishing component, and F is the actual travel speed of the polishing component.

5. The scraper mechanism as described in claim 1, characterized in that, The polishing components include: A grinding drive component is connected to the bracket; A grinding disc is rotatably connected to the bracket and driven by the grinding drive component, the grinding drive component being used to drive the grinding disc to rotate; and Multiple grinding components are connected to the grinding disc, and all of the grinding components are used to grind the protrusions on the printed surface.

6. The scraper mechanism as described in claim 5, characterized in that, The grinding disc includes a connecting portion and a mounting portion connected together. The connecting portion is connected to the bracket and has a connecting hole. The mounting portion has a cavity communicating with the connecting hole. The connecting part is used to connect to an external air extraction device to extract grinding waste from the cavity through the connecting hole.

7. The scraper mechanism as described in claim 6, characterized in that, Each of the grinding parts is arc-shaped, and the concave side of each of the grinding parts faces the rotation direction of the mounting part.

8. The scraper mechanism as described in claim 6, characterized in that, The grinding assembly also includes a lifting drive component connected to the bracket. The grinding disc is connected to the bracket via the lifting drive component, and the lifting drive component is used to drive the grinding disc to move closer to or away from the bracket.

9. The scraper mechanism as described in claim 5, characterized in that, The scraper mechanism includes multiple sets of grinding components and multiple sets of detection components. The multiple sets of grinding components and multiple sets of detection components are arranged sequentially along the length direction of the scraper component, and the grinding range of the grinding parts of the multiple grinding components covers the powder spreading range of the scraper component.

10. A 3D printing powder spreading method, based on the scraper mechanism as described in any one of claims 1-9, characterized in that, The powder spreading method includes the following steps: Control the support to move along the powder spreading direction; The control and detection components detect whether there are any printing surface protrusions on the flat surface; When the detection component is controlled to have a printing surface protrusion on the flat surface, it measures the height of the printing surface protrusion. The control polishing component polishes the printing surface protrusion when the height of the protrusion is greater than a preset height, and the preset height is less than the powder thickness; Control the scraper assembly to spread the powder.

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