A method and system for online warpage detection based on 3D printing

Abstract

This invention belongs to the field of additive manufacturing technology, specifically relating to an online warpage detection method and system based on 3D printing. The invention involves setting an extended model around a model of a part to be printed, forming a printing model; performing multi-layer 3D printing based on the printing model, and obtaining the height of the extended model for each printing layer to obtain actual height data; calculating the height difference between the actual height data and the corresponding standard height data to obtain warpage data; and controlling the 3D printer to continue or stop 3D printing based on the warpage data. This invention can avoid direct printing failure due to severe warpage deformation during printing, thus improving the printing success rate and the forming quality and precision of the part itself.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, specifically relating to an online warpage detection method and system based on 3D printing. Background Technology

[0002] In aerospace, shipbuilding, and other industrial sectors, large-sized complex components increasingly utilize complex structural designs and polymer-based composite materials to replace metal materials due to the technical requirements of lightweight, high strength, and multifunctionality. This results in lightweight, high-strength functional components. Fused deposition modeling (FDM) 3D printing technology, in principle, can achieve one-piece molding of complex structures of any size and is compatible with most 3D printing polymers and composite materials, making it the most suitable manufacturing method for large-sized composite component parts. However, the severe warping and deformation phenomenon that occurs during the printing process of high-performance composite materials, such as polyetheretherketone (PEEK) composites, has always been one of the most prominent technological challenges in FDM 3D printing.

[0003] The warping deformation of large-size composite material fused deposition modeling (FDM) is mainly due to the internal stress generated in the structure caused by the uneven melting and solidification of the material. The anisotropy of 3D printing exacerbates the accumulation of internal stress. This deformation is an inherent phenomenon of uneven material morphology and is difficult to completely avoid. Summary of the Invention

[0004] The purpose of this invention is to provide an online warpage detection method based on 3D printing, which can solve the technical problem of severe warpage deformation during large-size composite material fused deposition modeling 3D printing.

[0005] The technical solution of the present invention: In order to achieve the above-mentioned objective, in a first aspect, the present disclosure provides a warpage detection method based on 3D printing, comprising: setting an extended model around a model of a part to be printed to form a printing model; performing multi-layer 3D printing according to the printing model, and obtaining the height of the extended model of each printing layer to obtain actual height data; calculating the height difference based on the actual height data and the corresponding standard height data to obtain warpage data; and controlling the 3D printer to continue or stop 3D printing based on the warpage data.

[0006] Optionally, the extended model is a model of multiple cross-shaped prisms; the model of multiple cross-shaped prisms surrounds the model of the part to be printed; the cross-shaped prisms have a cross-shaped cross section along the plane parallel to the printing base surface.

[0007] Optionally, the cross-shaped column, with the intersection as the boundary, includes: a first expansion plate, which is a plate on the side away from the model of the part to be printed; a second expansion plate, which is a plate perpendicular to the first expansion plate; a third expansion plate, which is a plate perpendicular to the first expansion plate and symmetrical to the second expansion plate along the intersection; and a fourth expansion plate, which is a plate on the side closer to the model of the part to be printed, and is used to connect the model of the part to be printed; the actual height data of the first expansion plate, the actual height data of the second expansion plate, and the actual height data of the third expansion plate are respectively compared with the corresponding standard height data to calculate the height difference, and then the height difference is quantitatively analyzed to obtain warping data.

[0008] Optionally, calculating the height difference between the actual height data of the first expansion board, the second expansion board, and the third expansion board and their corresponding standard height data, and then quantifying and analyzing the height difference to obtain warping data includes: extracting the actual height data of the first expansion board, the second expansion board, and the third expansion board using a feature recognition algorithm; comparing the actual height data with the corresponding standard height data to obtain the height difference; establishing a discrete distribution coordinate system for the height difference based on the height difference; performing fitting operations on the discrete points of the height difference in the discrete distribution coordinate system to obtain a warping deformation distribution surface; and using the warping deformation distribution surface to determine the warping data.

[0009] Optionally, fitting the discrete points of the height difference in the discrete distribution coordinate system to obtain the warped deformation distribution surface includes: performing interpolation fitting on the discrete points corresponding to the height difference between the second extension plate and the third extension plate in the discrete distribution coordinate system to obtain the warped deformation distribution curve; and fitting the warped deformation distribution surface based on the discrete points of the height difference of the first extension plate and the warped deformation distribution curve.

[0010] Optionally, determining the warping data using the warped deformation distribution surface includes: calculating the maximum height difference between the actual height data of the i-th layer and the standard height data of the i-th layer to obtain the deformation data of the i-th layer; where i is a natural number greater than or equal to 1; the warping data includes the deformation data.

[0011] Optionally, controlling the 3D printer to continue or stop 3D printing based on the warp data includes: stopping 3D printing if the deformation data of the i-th layer is greater than or equal to a first threshold.

[0012] Optionally, if the deformation data of the i-th layer is less than a first threshold, determining the warped data using the warped deformation distribution surface further includes: based on the warped deformation distribution surface, setting a preset data acquisition cycle time; calculating the height difference between the actual height data printed at the initial moment of the n-th cycle and the standard height data at the initial moment of the n-th cycle; calculating the height difference between the actual height data printed at the end moment of the n-th cycle and the standard height data at the end moment of the n-th cycle; calculating the difference between the height differences at the same horizontal and vertical coordinate positions at the initial moment and the end moment of the n-th cycle in a discrete distribution coordinate system, taking the maximum difference to obtain the deformation increment of the n-th cycle; where n is a natural number greater than or equal to 1; the warped data includes the deformation increment.

[0013] Optionally, controlling the 3D printer to continue or stop 3D printing based on the warp data includes: stopping 3D printing if the deformation increment of the nth period is greater than or equal to a second threshold.

[0014] Optionally, if the deformation increment of the i-th layer is less than the second threshold, determining the warping data using the warped deformation distribution surface further includes: based on the warped deformation distribution surface, calculating the sum of the height differences at the same horizontal and vertical coordinate positions in each period from the m-th to the n-th period in the discrete distribution coordinate system, taking the minimum cumulative value to obtain the cumulative deformation increment; if the cumulative deformation increment is less than the third threshold, continuing 3D printing; if the cumulative deformation increment is greater than or equal to the third threshold, stopping 3D printing; where m is a natural number less than n; the warping data includes the cumulative deformation increment.

[0015] According to a specific embodiment proposed in the specific implementation process of the present invention, in a second aspect, the present disclosure provides a 3D printing-based online warpage detection system, comprising: a modeling unit, the modeling unit being used to set an extended model around a model of a part to be printed to form a printing model; a data acquisition unit, the data acquisition unit being used to acquire the height of the extended model of each printing layer during multi-layer 3D printing to obtain actual height data; a processing unit, the processing unit being used to calculate the height difference based on the actual height data and the corresponding standard height data to obtain warpage data; and a control unit, the control unit being used to control the 3D printer to continue or stop 3D printing based on the warpage data.

[0016] Compared with existing technologies, the technical solution proposed in this invention has at least the following beneficial effects: The online warpage detection method proposed in this invention is an online detection method for warpage deformation of large-size high-performance polymer and composite material parts in 3D printing, effectively solving the technical problem of severe warpage deformation during large-size composite material fused deposition modeling 3D printing; the online warpage detection method proposed in this invention has low execution cost and wide applicability to parts. By performing real-time image acquisition and in-depth analysis of the printed structure, this invention can promptly detect severe unevenness of the top surface of the printed structure and severe deterioration of the adhesion between the bottom and the printing base surface caused by excessive warpage deformation at any time. It can also detect severe deterioration of warpage deformation and interlayer splitting and detachment, and immediately pause printing, effectively avoiding further damage to the nozzle and the printed structure, and a large waste of materials and time. After processing and repair, normal printing can continue, avoiding direct failure of printing parts due to severe warpage deformation without detection, thus improving the printing success rate. Attached Figure Description

[0017] Figure 1 This is a flowchart of the online warpage detection method based on 3D printing of the present invention;

[0018] Figure 2 This is a schematic diagram of the 3D printing state according to an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of a discrete distribution coordinate system according to an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the warping deformation distribution curve of an embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of a warped deformation distribution surface according to an embodiment of the present invention;

[0022] Figure 6 This is a schematic diagram of a cross-shaped column according to an embodiment of the present invention;

[0023] Wherein: 100: cross-shaped column; 110: first expansion plate; 120: second expansion plate; 130: third expansion plate; 140: fourth expansion plate; 200: part to be printed; 300: filling part; 400: acquisition unit. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] According to specific embodiments proposed in the implementation process of the present invention, in a first aspect, the present disclosure provides a 3D printing-based online warpage detection method, which may include: setting an extended model around a model of a part to be printed to form a printing model; performing multi-layer 3D printing according to the printing model, and obtaining the height of the extended model of each printing layer to obtain actual height data; calculating the height difference based on the actual height data and the corresponding standard height data to obtain warpage data; and controlling the 3D printer to continue or stop 3D printing based on the warpage data.

[0026] The online warpage detection method proposed in this invention is an online detection method for warpage deformation of large-size high-performance polymer and composite material parts in 3D printing. This method is low-cost and applicable to a wide range of parts. It can avoid direct printing failure due to severe warpage deformation, thus improving the printing success rate and the forming quality and precision of the part itself.

[0027] The online warpage detection method proposed in this invention pertains to the monitoring of the fused deposition modeling process. By acquiring and analyzing real-time images of the printed structure, it can promptly detect severe unevenness on the top surface of the printed structure and serious deterioration of the adhesion between the bottom and the printing substrate caused by excessive warpage at any given moment. Simultaneously, it can detect severe deterioration of warpage deformation and interlayer splitting and detachment, and immediately pause printing. This effectively avoids further damage to the nozzle and the printed structure, as well as significant waste of materials and time. Furthermore, after processing and repair, normal printing can continue, preventing direct failure of part printing due to severe warpage deformation without detection, thus improving the printing success rate.

[0028] The online warpage detection method proposed in the specific implementation of this invention extends the design of the part structure, and uniformly uses the cross-shaped feature structure (i.e., cross-shaped column 100) which is easy to form and convenient for online detection as the structural feature object for warpage deformation analysis and calculation. Combined with the technical idea of ​​deriving the overall warpage deformation of the structure from the boundary warpage deformation, the warpage deformation analysis algorithm is greatly simplified, and the compatibility of the online detection method with various complex structures is fully guaranteed.

[0029] The online warpage detection method proposed in this invention utilizes a 3D printing system with online image detection capabilities. This system can acquire image data of the printed structure during the part printing process. Simultaneously, it employs a warpage deformation analysis algorithm targeting the Z-axis (the direction perpendicular to the plane where the printing base is located during 3D printing) to perform real-time quantitative analysis of the warpage deformation state. By comparing the warpage deformation state with previous states, it further analyzes the degree of warpage deformation deterioration over a period of time, thereby achieving online warpage detection in large-size high-performance polymer and composite material 3D printing.

[0030] Figure 1 A flowchart of an online warp detection method based on 3D printing according to an embodiment of the present disclosure is shown. Figure 2 A schematic diagram of a 3D printing state according to an embodiment of the present disclosure is shown.

[0031] like Figure 1 and Figure 2 As shown, in some embodiments, the online warpage detection method includes at least the following steps:

[0032] S100. Set up an extended model around the model of the part to be printed to form a printing model.

[0033] S200. Perform multi-layer 3D printing based on the printing model, and obtain the height of the extended model for each printing layer to obtain the actual height data.

[0034] S300. Calculate the height difference based on the actual height data and the corresponding standard height data to obtain the warping data.

[0035] S400: Based on the warping data, control the 3D printer to continue or stop 3D printing.

[0036] In some embodiments, step S400 may include:

[0037] S410. Based on the warping data, control the 3D printer to stop 3D printing.

[0038] S420: Based on the warping data, control the 3D printer to continue 3D printing.

[0039] In some embodiments, step S300 may include:

[0040] S310. Calculate the height difference between the actual height data of the first expansion plate 110, the actual height data of the second expansion plate 120 and the actual height data of the third expansion plate 130 and the corresponding standard height data, and then perform quantitative analysis on the height difference to obtain warping data.

[0041] Figure 3A schematic diagram of a discrete distributed coordinate system according to an embodiment of the present disclosure is shown.

[0042] Figure 4 A schematic diagram of a warping deformation distribution curve according to an embodiment of the present disclosure is shown.

[0043] Figure 5 A schematic diagram of a warped deformation distribution surface according to an embodiment of the present disclosure is shown.

[0044] like Figure 3 , Figure 4 and Figure 5 As shown, in some embodiments, step S310 may include:

[0045] S311. Use a feature recognition algorithm to extract the actual height data of the first expansion plate 110, the second expansion plate 120 and the third expansion plate 130 respectively.

[0046] S312. The actual height data of the first expansion plate 110, the second expansion plate 120 and the third expansion plate 130 are compared with the corresponding standard height data to obtain the height difference.

[0047] S313. Establish a discrete distribution coordinate system for the height difference based on the height difference.

[0048] In step S313, a discrete coordinate system for the height difference is established, with the height difference as the Z-axis, the horizontal axis of the plane containing the printing base surface as the X-axis, and the vertical axis of the plane containing the printing base surface as the Y-axis. It should be noted that, in a preferred embodiment, during the 3D printing process, the shape formed by the second extension plates 120 and the third extension plates 130 of all the cross-shaped prisms 100 is a polygonal prism frame. The extended model and the model of the part to be printed are connected together by the filling part 300. For ease of calculation, the values ​​of the X-axis, Y-axis, and Z-axis are all positive values ​​at the 0 point, i.e., all are positive numbers.

[0049] S314. Perform fitting operations on the discrete points of the height difference in the discrete distribution coordinate system to obtain the warped deformation distribution surface.

[0050] S315. Determine the warping data using the warping deformation distribution surface;

[0051] The actual height data of the first expansion plate 110 extracted in step S311 is the actual height data of the free end of the first expansion plate 110.

[0052] The actual height data of the second expansion plate 120 extracted in step S311 is the actual height data of the free end of the second expansion plate 120.

[0053] The actual height data of the third expansion plate 130 extracted in step S311 is the actual height data of the free end of the third expansion plate 130.

[0054] In some embodiments, step S314 may include:

[0055] S3141. In the discrete distribution coordinate system, the discrete points corresponding to the height difference between the second expansion plate 120 and the third expansion plate 130 are interpolated and fitted to obtain the warping deformation distribution curve.

[0056] S3142. Based on the discrete points of the height difference of the first extension plate 110 and the warping deformation distribution curve, a warping deformation distribution surface is obtained by fitting.

[0057] In step S3141, a one-dimensional interpolation method is used to fit the discrete points of the height difference to obtain the warping deformation distribution curve.

[0058] In step S3142, a two-dimensional interpolation method is used to fit the discrete points of the height difference of the first expansion plate 110 and the warping deformation distribution curve to obtain a warping deformation distribution surface. In this step, the center of the smallest circumcircle of the pattern enclosed by the cross-shaped prism 100 on the plane where the printing base is located is used as the vertex, and a surface passing through the discrete points of the warping deformation distribution curve and the height difference of the first expansion plate 110 is fitted in the Z-axis extension direction, that is, the warping deformation distribution surface.

[0059] In some embodiments, step S315 may include:

[0060] S3151. Calculate the maximum value of the height difference between the actual height data of the i-th layer and the standard height data of the i-th layer to obtain the deformation data of the i-th layer;

[0061] Where i is a natural number greater than or equal to 1.

[0062] If the deformation data of the i-th layer is greater than or equal to the first threshold, proceed to step S410.

[0063] It should be noted that the first threshold is the critical top surface unevenness data. If the unevenness exceeds the first threshold, it is considered that the warping deformation makes it impossible to deposit and form normally on the printed structure. Printing is immediately paused, and the current warping deformation status is reported while waiting for the top surface to be repaired and flattened.

[0064] If the deformation data of the i-th layer is less than the first threshold, execute steps S3152 and S3153.

[0065] S3152. Based on the warped deformation distribution surface, a preset data acquisition cycle time is set; the height difference between the actual height data printed at the initial moment of the nth cycle and the standard height data at the initial moment of the nth cycle is calculated.

[0066] S3153. Calculate the height difference between the actual height data printed at the end of the nth cycle and the standard height data at the end of the nth cycle.

[0067] S3154. Calculate the height difference between the same horizontal and vertical coordinate positions at the initial and final times of the nth period in the discrete coordinate system, and take the maximum difference to obtain the deformation increment of the nth period. If the deformation increment of the nth period is greater than or equal to the second threshold, proceed to step S410. If the deformation increment of the nth period is less than the second threshold, proceed to step S3155.

[0068] It should be noted that the second threshold is the critical maximum deformation increment for a single cycle. If it is greater than or equal to the second threshold, it is considered that the warping deformation state has deteriorated drastically or there is interlayer splitting and separation. Printing is immediately suspended, and the warping deformation increment is fed back, waiting for the printed structure to be repaired or reinforced.

[0069] S3155. Based on the warped deformation distribution surface, calculate the sum of the height differences at the same horizontal and vertical coordinate positions in each period from the mth to the nth period in the discrete distribution coordinate system, and take the minimum cumulative value to obtain the cumulative deformation increment.

[0070] If the cumulative deformation increment is less than the third threshold, proceed to step S420.

[0071] If the cumulative deformation increment is greater than or equal to the third threshold, proceed to step S410.

[0072] It should be noted that the third threshold is the critical minimum deformation increment over several cycles. If the third threshold is exceeded, it is considered that the warping deformation has caused a severe deterioration in the adhesion between the bottom layer of the printed structure and the printing base surface. Printing is immediately suspended, and the warping deformation increment is fed back while waiting for the bottom of the printed structure to be bonded and strengthened.

[0073] In some embodiments, after steps S3151, S3152, S3153, S3154, and S3155 are completed, steps S3152, S3153, S3154, and S3155 are repeated several times.

[0074] In some embodiments, step S3151 is repeated after steps S3152, S3153, S3154, and S3155.

[0075] Figure 6A schematic diagram of a cross-shaped column according to an embodiment of the present disclosure is shown.

[0076] like Figure 6 As shown, in some embodiments, the extended model is a plurality of cross-shaped column models 100, which surround the model of the part to be printed 200. The cross-shaped column 100 has a cross-shaped cross section along the plane parallel to the printing base surface.

[0077] It should be noted that the model of the part to be printed 200 is a model of the part to be printed 200, that is, a model of the part to be printed 200 formed in the computer before 3D printing. The model of the cross-shaped prism 100 is a model of the cross-shaped prism 100, that is, a model of the cross-shaped prism 100 formed in the computer before 3D printing. The model of the filling part 300 is a model of the filling part 300, that is, a model of the filling part 300 formed in the computer before 3D printing. Since the warping deformation is mainly manifested at the top boundary of the structure, in order to reduce the difficulty of image acquisition and analysis, the technical idea of ​​using the top boundary as the direct detection object and deriving the overall warping deformation of the structure based on the boundary warping deformation is adopted.

[0078] Furthermore, to simplify the warpage deformation analysis algorithm and ensure the compatibility of the online detection method with various complex structures, the warpage online detection method proposed in the specific implementation of this invention extends the design of the part by arranging an outer shell with a cross-shaped feature structure on the outside of the part. The two are connected by a filling part, and the cross-shaped feature structure (i.e., the cross-shaped column 100) is uniformly used as the structural object for warpage deformation analysis. The cross-shaped feature structure is easy to model, easy to form, easy to identify and extract features, and the extracted features are easy to calculate and analyze.

[0079] like Figure 2 As shown, in some embodiments, the extended model is a plurality of cross-shaped pillars, which surround the model of the part to be printed 200, and the cross-shaped pillars have a cross-shaped cross section along the plane parallel to the printing base surface.

[0080] In some embodiments, the step of setting an extension model around the model of the part to be printed 200 to form a printable model includes: setting a filling part 300 model between the model of the part to be printed 200 and the extension model to obtain the printable model, wherein the filling part 300 model is used to connect the model of the part to be printed 200 and the extension model into a whole.

[0081] In some embodiments, the filling part 300 model is one or more of a linear structure, a mesh structure, a solid structure, etc.

[0082] In some embodiments, the filling part 300 model is a straight line structure, and the filling part 300 model is connected to the fourth expansion plate 140.

[0083] In some embodiments, the filling part 300 model is an extension of the free end of the fourth expansion plate 140 of the cross-shaped column 100, and the free end of the fourth expansion plate 140 extends to contact the model of the part to be printed 200.

[0084] In some embodiments, obtaining the height of the extended model for each printed layer includes: acquiring an image of the cross-shaped column 100 during 3D printing using an image acquisition device, and extracting the actual height of each position of the cross-shaped column 100 (i.e., the first extended plate 110, the second extended plate 120, and the third extended plate 130) in the image using a feature recognition algorithm.

[0085] In practical applications, before 3D printing, a model of the part to be printed (200) is designed. This disclosure involves designing the model of the part to be printed (200) and simultaneously setting up an extension model around it to form a printing model. Then, the printing model is processed to generate a Gcode file, which is imported into the 3D printing system to begin 3D printing. During the 3D printing process, the 3D printer prints layer by layer.

[0086] In some embodiments, an image acquisition device is used to obtain the actual height of the extended model for each printed layer.

[0087] It should be noted that the standard height data refers to the height data of the 200 model of the part to be printed, including the height data of each layer.

[0088] In some embodiments, the cross-shaped column 100 is divided by the intersection position, and the cross-shaped column 100 may include: a first extension plate 110, which is a plate on the side away from the model of the part to be printed 200.

[0089] In some embodiments, the cross-shaped column 100 may include a second extension plate 120, which is a plate perpendicular to the first extension plate 110.

[0090] In some embodiments, the cross-shaped column 100 may include a third extension plate 130, which is a plate perpendicular to the first extension plate 110 and symmetrical to the second extension plate 120 along the intersection position.

[0091] In some embodiments, the cross-shaped column 100 may include a fourth expansion plate 140, which is a plate close to the side of the model of the part to be printed 200, and the fourth expansion plate 140 is used to connect the model of the part to be printed 200.

[0092] It should be noted that the cross-shaped column 100 can be regarded as two intersecting plates, and the straight line where the two plates intersect is considered the intersection point, which is perpendicular to the printing base surface. One plate consists of the second expansion plate 120 and the third expansion plate 130, which are divided into the second expansion plate 120 and the third expansion plate 130 at the intersection point; the other plate consists of the first expansion plate 110 and the fourth expansion plate 140, which are also divided into the first expansion plate 110 and the fourth expansion plate 140 at the intersection point.

[0093] In some embodiments, calculating the height difference based on the actual height data and the corresponding standard height data to obtain warpage data may include: calculating the height difference between the actual height data of the first expansion board 110, the second expansion board 120, and the third expansion board 130 and their corresponding standard height data, and then quantifying and analyzing the height difference to obtain warpage data. It should be noted that the height difference is calculated between the actual height data of the first expansion board 110 and the corresponding standard height data, the actual height data of the second expansion board 120 and the corresponding standard height data, and the actual height data of the third expansion board 130 and the corresponding standard height data.

[0094] In some embodiments, the actual height data of the first expansion plate 110, the second expansion plate 120, and the third expansion plate 130 are respectively compared with the corresponding standard height data to calculate the height difference. The height difference is then quantified to obtain warping data. This includes: extracting the actual height data of the first expansion plate 110, the second expansion plate 120, and the third expansion plate 130 using a feature recognition algorithm; comparing the actual height data with the corresponding standard height data to obtain the height difference; establishing a discrete distribution coordinate system for the height difference based on the height difference; performing fitting operations on the discrete points of the height difference in the discrete distribution coordinate system to obtain a warping deformation distribution surface; and using the warping deformation distribution surface to determine the warping data.

[0095] In some embodiments, fitting the discrete distribution coordinate system to obtain the warped deformation distribution surface includes: performing interpolation fitting on the discrete points corresponding to the height difference between the second extension plate and the third extension plate in the discrete distribution coordinate system to obtain the warped deformation distribution curve; and fitting the warped deformation distribution surface based on the discrete points of the height difference of the first extension plate and the warped deformation distribution curve.

[0096] In the discrete distribution coordinate system, discrete points of the height difference between the second expansion plate 120 and the third expansion plate 130 are selected to construct a two-dimensional coordinate system for distribution curve fitting calculation. The vertical axis is the same as the vertical axis of the discrete distribution coordinate system, which is the height difference. The horizontal axis is set as T(x, y), where x is the plane X-axis coordinate value during actual printing, and y is the plane Y-axis coordinate value during actual printing.

[0097] Based on the arrangement of the second expansion plates 120 and the third expansion plates 130 around the outer ring of the model to be printed 200, starting from any expansion plate, adjacent expansion plates are selected sequentially in a fixed clock direction (either clockwise or counterclockwise). The discrete points of the height difference between adjacent expansion plates are arranged along a fixed coordinate axis on the horizontal axis T of the two-dimensional coordinate system (either positive or negative). The distance between the discrete points of the height difference between two adjacent expansion plates L_1 and L_2 on the T-axis is the actual XY plane distance during printing, i.e., √((x_1-x_2)^2+(y_1-y_2)^2), where x_1 and y_1 are the actual X-axis and Y-axis coordinates of expansion plate L_1 during printing, and x_2 and y_2 are the actual X-axis and Y-axis coordinates of expansion plate L_2 during printing.

[0098] In the two-dimensional coordinate system, a one-dimensional interpolation method is used to fit the discrete points of the height difference between each of the second extension plate 120 and the third extension plate 130 to generate a distribution curve of the height difference on the T-axis. Optionally, B-spline interpolation fitting method is used.

[0099] The height difference distribution curve on the T-axis is transformed into the warped deformation distribution curve located within the boundary of the discrete distribution coordinate system. Optionally, the method is as follows: using the vertical coordinate value in the two-dimensional coordinate system as the vertical coordinate value in the discrete distribution coordinate system, the horizontal coordinate value T(x, y) in the two-dimensional coordinate system is restored to the planar coordinate points on the actual printing distance X of the horizontal axis and the actual printing distance Y of the vertical axis in the discrete distribution coordinate system, forming the warped deformation distribution curve in the discrete coordinate system.

[0100] It should be noted that a two-dimensional interpolation method is used to fit the Z-axis warping deformation (i.e., the height difference) on the top surface of the extended model, generating a warping deformation distribution surface for the entire printed model. This warping deformation distribution surface passes through the distribution curve and the discrete points of each height difference, thus obtaining the overall real-time warping deformation state. Optionally, Parabolic 2D nonlinear fitting is used, z = a*x² + b*y² + c*x + d*y + z₀. a, b, c, d, and z₀ are constants, x and y are the X-axis and Y-axis coordinates at the same discrete point, and z is the height difference at the (x, y) coordinate.

[0101] In some embodiments, determining the warping data using the warped deformation distribution surface includes: calculating the maximum value of the height difference between the actual height data of the i-th layer and the standard height data of the i-th layer to obtain the deformation data of the i-th layer; wherein i is a natural number greater than or equal to 1, and the warping data includes the deformation data.

[0102] In some embodiments, controlling the 3D printer to continue or stop 3D printing based on the warp data includes: stopping 3D printing if the deformation data of the i-th layer is greater than or equal to a first threshold.

[0103] In some embodiments, determining the warped data using the warped deformation distribution surface if the deformation data of the i-th layer is less than a first threshold further includes: based on the warped deformation distribution surface, setting a preset data acquisition cycle time; calculating the height difference between the actual height data printed at the initial moment of the n-th cycle and the standard height data at the initial moment of the n-th cycle; calculating the height difference between the actual height data printed at the end moment of the n-th cycle and the standard height data at the end moment of the n-th cycle; calculating the difference between the height differences at the same horizontal and vertical coordinate positions at the initial moment and the end moment of the n-th cycle in a discrete distribution coordinate system, taking the maximum difference to obtain the deformation increment of the n-th cycle; wherein, n is a natural number greater than or equal to 1; the warped data includes the deformation increment.

[0104] In some embodiments, the data acquisition cycle time is manually defined and can be preset according to factors such as the size and shape of the part to be printed.

[0105] In some embodiments, the time for printing one layer is divided into several data acquisition cycle times.

[0106] In some embodiments, controlling the 3D printer to continue or stop 3D printing based on the warp data includes: stopping 3D printing if the deformation increment of the nth period is greater than or equal to a second threshold.

[0107] In some embodiments, if the deformation increment of the nth period is less than a second threshold, determining the warping data using the warped deformation distribution surface further includes: based on the warped deformation distribution surface, calculating the sum of the height differences at the same horizontal and vertical coordinate positions in each period from the mth to the nth period in a discrete distribution coordinate system, taking the minimum cumulative value to obtain the cumulative deformation increment; if the cumulative deformation increment is less than a third threshold, continuing 3D printing; if the cumulative deformation increment is greater than or equal to the third threshold, stopping 3D printing; where m is a natural number less than n; the warping data includes the cumulative deformation increment.

[0108] According to the specific embodiments proposed in the specific implementation process of the present invention, in another aspect, the present disclosure provides a 3D printing-based online warpage detection system, which may include: a modeling unit, the modeling unit being used to set an extended model around the model of the part to be printed 200 to form a printing model; a data acquisition unit 400, the data acquisition unit 400 being used to perform multi-layer 3D printing according to the printing model, and to acquire the height of the extended model of each printing layer to obtain actual height data; a processing unit, the processing unit being used to calculate the height difference based on the actual height data and the corresponding standard height data to obtain warpage data; and a control unit, the control unit being used to control the 3D printer to continue or stop 3D printing based on the warpage data.

[0109] In the specific implementation of this invention, the online warping detection system uses the acquired image data and a warping deformation analysis algorithm to judge the warping deformation state of the printed structure in real time, and compares and analyzes the warping deformation increment over a period of time. For severe and drastically deteriorated warping deformation, the printing process is paused in time and corresponding feedback is given.

[0110] The processing unit is further configured to calculate the height difference between the actual height data of the first expansion plate 110, the actual height data of the second expansion plate 120 and the actual height data of the third expansion plate 130 and the corresponding standard height data, and then perform quantitative analysis on the height difference to obtain warping data.

[0111] The processing unit is also used to extract the actual height data of the first expansion plate 110, the second expansion plate 120 and the third expansion plate 130 respectively using a feature recognition algorithm.

[0112] The processing unit is further configured to compare the actual height data with the corresponding standard height data to obtain the height difference.

[0113] The processing unit is also used to establish a discrete distribution coordinate system for the height difference based on the height difference.

[0114] The processing unit is also used to perform fitting operations on the discrete points of the height difference in the discrete distribution coordinate system to obtain the warped deformation distribution surface.

[0115] The processing unit is also used to determine the warping data using the warping deformation distribution surface.

[0116] The processing unit is further configured to perform interpolation fitting operations on discrete points corresponding to the height difference between the second expansion plate 120 and the third expansion plate 130 in the discrete distribution coordinate system to obtain the warping deformation distribution curve.

[0117] The processing unit is also used to fit a warping deformation distribution surface based on the discrete points of the height difference of the first extension plate 110 and the warping deformation distribution curve.

[0118] The processing unit is further configured to calculate the maximum height difference between the actual height data of the i-th layer and the standard height data of the i-th layer, to obtain the deformation data of the i-th layer; wherein i is a natural number greater than or equal to 1; the warping data includes the deformation data.

[0119] The processing unit is further configured to compare the deformation data of the i-th layer with a first threshold; if the deformation data of the i-th layer is greater than or equal to the first threshold, a stop command is sent to the control unit, and the control unit controls the 3D printer to stop 3D printing according to the stop command.

[0120] If the deformation data of the i-th layer is less than a first threshold, the processing unit is further configured to: preset a data acquisition cycle time based on the warped deformation distribution surface; calculate the height difference between the actual height data printed at the initial moment of the n-th cycle and the standard height data at the initial moment of the n-th cycle; calculate the height difference between the actual height data printed at the end moment of the n-th cycle and the standard height data at the end moment of the n-th cycle; calculate the height difference between the same horizontal and vertical coordinate positions at the initial moment and the end moment of the n-th cycle in a discrete distribution coordinate system, take the maximum difference, and obtain the deformation increment of the n-th cycle; where n is a natural number greater than or equal to 1; the warped data includes the deformation increment.

[0121] The processing unit is further configured to compare the deformation increment of the nth period with a second threshold; if the deformation increment of the nth period is greater than or equal to a first threshold, a stop command is sent to the control unit, and the control unit controls the 3D printer to stop 3D printing according to the stop command.

[0122] If the deformation increment of the nth period is less than the second threshold, the processing unit is further configured to calculate the sum of the height differences at the same horizontal and vertical coordinate positions in each period from the mth period to the nth period in the discrete distribution coordinate system based on the warped deformation distribution surface, and take the minimum cumulative value to obtain the cumulative deformation increment; wherein, m is a natural number less than n; the warped data includes the cumulative deformation increment.

[0123] The processing unit is further configured to compare the cumulative deformation increment with a third threshold; if the cumulative deformation increment is greater than or equal to the third threshold, a stop command is sent to the control unit, and the control unit controls the 3D printer to stop 3D printing according to the stop command.

[0124] The warping data may include one or more of the deformation data, the deformation increment, and the cumulative deformation increment.

[0125] This disclosure provides a 3D printer, which includes the online warpage detection system described in any of the above technical solutions, and can execute the online warpage detection method described in any of the above technical solutions.

[0126] This disclosure provides a 3D printing system, which includes the 3D printer described in any of the above technical solutions.

[0127] Large-sized, complex structural parts are fabricated using a fused deposition modeling (FDM) 3D printing system with online image inspection capabilities. In addition to the mechanical components and control system required for a fused deposition modeling 3D printer, the system also includes two image acquisition devices with data transmission channels, an image data storage device, and an image data processing system. The printing material is a PEEK-based composite material.

[0128] In another embodiment of this disclosure, an electronic device is provided for an audio / video processing method based on display position. The electronic device includes: at least one processor; and a memory communicatively connected to the at least one processor. The memory stores instructions executable by the at least one processor, which, when executed, enable the at least one processor to: set an extended model around a model of a part to be printed, forming a printable model; perform multi-layer 3D printing based on the printable model, and obtain the height of the extended model for each print layer to obtain actual height data; calculate the height difference based on the actual height data and corresponding standard height data to obtain warpage data; and control the 3D printer to continue or stop 3D printing based on the warpage data.

[0129] In yet another embodiment of this disclosure, a non-volatile computer storage medium is provided, the computer storage medium storing computer-executable instructions that can execute the 3D printing-based online warpage detection method in any of the above method embodiments.

[0130] This disclosure aims to protect a method and system for online warpage detection based on 3D printing. The online warpage detection method may include: setting an extended model around a model of a part to be printed to form a printed model; performing multi-layer 3D printing based on the printed model and obtaining the height of the extended model for each printed layer to obtain actual height data; calculating the height difference based on the actual height data and the corresponding standard height data to obtain warpage data; and controlling the 3D printer to continue or stop 3D printing based on the warpage data. The online warpage detection method proposed in this invention is an online detection method for warpage deformation of large-size high-performance polymer and composite material parts printed by 3D printing. This method has low execution cost and wide applicability to various parts. It can avoid direct printing failure due to severe warpage deformation during printing, thus improving the printing success rate and the forming quality and accuracy of the part itself.

[0131] The units described in the embodiments of this disclosure can be implemented in software or in hardware. The names of the units are not necessarily limiting in certain circumstances; for example, a modeling unit can also be described as "a unit that sets an extended model around a model of a part to be printed to form a printable model."

[0132] The above description is merely a specific embodiment of the present invention, providing a detailed description of the invention. Parts not covered herein are conventional techniques. However, the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for online warpage detection based on 3D printing, characterized in that, An extended model is set around the model of the part to be printed to form a printing model; multi-layer 3D printing is performed according to the printing model, and the height of the extended model of each printing layer is obtained to obtain actual height data; the height difference is calculated based on the actual height data and the corresponding standard height data to obtain warping data; the 3D printer is controlled to continue or stop 3D printing based on the warping data. The extended model is a model of multiple cross-shaped prisms; the model of multiple cross-shaped prisms surrounds the model of the part to be printed; the cross-shaped prisms have a cross-shaped cross section along the plane parallel to the printing base surface; The cross-shaped prism, divided by its intersection, includes: a first expansion plate, located away from the model to be printed; a second expansion plate, perpendicular to the first expansion plate; a third expansion plate, perpendicular to the first expansion plate and symmetrical to the second expansion plate along the intersection; and a fourth expansion plate, located closer to the model to be printed, used to connect the model. The actual height data of the first, second, and third expansion plates are compared with their corresponding standard height data to calculate the height difference. This height difference is then quantified to obtain warping data. During 3D printing, the shape formed by the second and third expansion plates of all the cross-shaped prisms constitutes a polygonal prism frame.

2. The online warpage detection method based on 3D printing as described in claim 1, characterized in that, The actual height data of the first expansion board, the second expansion board, and the third expansion board are compared with their corresponding standard height data to calculate the height difference. The height difference is then quantified to obtain warping data. This process includes: extracting the actual height data of the first expansion board, the second expansion board, and the third expansion board using a feature recognition algorithm; comparing the actual height data with the corresponding standard height data to obtain the height difference; establishing a discrete distribution coordinate system for the height difference; performing fitting operations on the discrete points of the height difference in the discrete distribution coordinate system to obtain a warping deformation distribution surface; and using the warping deformation distribution surface to determine the warping data.

3. The online warpage detection method based on 3D printing as described in claim 2, characterized in that, The process of fitting discrete points of the height difference in the discrete distribution coordinate system to obtain a warped deformation distribution surface includes: performing interpolation fitting operations on discrete points corresponding to the height difference between the second extension plate and the third extension plate in the discrete distribution coordinate system to obtain a warped deformation distribution curve; and fitting a warped deformation distribution surface based on the discrete points of the height difference of the first extension plate and the warped deformation distribution curve.

4. The online warpage detection method based on 3D printing as described in claim 3, characterized in that, Determining the warping data using the warped deformation distribution surface includes: calculating the maximum height difference between the actual height data of the i-th layer and the standard height data of the i-th layer to obtain the deformation data of the i-th layer; where i is a natural number greater than or equal to 1; the warping data includes the deformation data.

5. The online warpage detection method based on 3D printing as described in claim 4, characterized in that, The method of controlling the 3D printer to continue or stop 3D printing based on the warping data includes: stopping 3D printing if the deformation data of the i-th layer is greater than or equal to a first threshold; and determining the warping data using the warping deformation distribution surface if the deformation data of the i-th layer is less than the first threshold. This further includes: setting a preset data acquisition cycle time based on the warping deformation distribution surface; calculating the height difference between the actual height data printed at the initial moment of the n-th cycle and the standard height data at the initial moment of the n-th cycle; calculating the height difference between the actual height data printed at the end moment of the n-th cycle and the standard height data at the end moment of the n-th cycle; calculating the height difference between the same horizontal and vertical coordinate positions at the initial moment and the end moment of the n-th cycle in a discrete coordinate system, taking the maximum difference to obtain the deformation increment of the n-th cycle; where n is a natural number greater than or equal to 1; and the warping data includes the deformation increment.

6. The online warpage detection method based on 3D printing as described in claim 5, characterized in that, The method of controlling the 3D printer to continue or stop 3D printing based on the warp data includes: stopping 3D printing if the deformation increment of the nth period is greater than or equal to a second threshold.

7. The online warpage detection method based on 3D printing as described in claim 5, characterized in that, If the deformation increment of the i-th layer is less than the second threshold, determining the warping data using the warped deformation distribution surface further includes: based on the warped deformation distribution surface, calculating the sum of the height differences at the same horizontal and vertical coordinate positions in each period from the m-th to the n-th period in the discrete distribution coordinate system, taking the minimum cumulative value to obtain the cumulative deformation increment; if the cumulative deformation increment is less than the third threshold, continuing 3D printing; if the cumulative deformation increment is greater than or equal to the third threshold, stopping 3D printing; where m is a natural number less than n; the warping data includes the cumulative deformation increment.

8. A 3D-printed online warpage detection system, used to implement the detection method as described in any one of claims 1 to 7, characterized in that, include: The system comprises: a modeling unit for setting an extended model around the model of the part to be printed to form a printing model; a data acquisition unit for acquiring the height of the extended model in each printing layer during multi-layer 3D printing to obtain actual height data; a processing unit for calculating the height difference based on the actual height data and the corresponding standard height data to obtain warpage data; and a control unit for controlling the 3D printer to continue or stop 3D printing based on the warpage data.

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