Surface printing method, device and system for shaped products

Abstract

The application relates to the field of inkjet printing technology, and particularly discloses a surface inkjet printing method, device and system for special-shaped products, which comprises the following steps: scanning a special-shaped product to be inkjet printed to determine the surface contour of the special-shaped product; determining the inkjet printing track of a nozzle and the surface to be inkjet printed according to the surface contour, the inkjet printing track and the surface of the special-shaped product always maintaining a preset distance; and controlling the nozzle to inkjet print the surface to be inkjet printed of the special-shaped product along the inkjet printing track. In this way, the inkjet printing track of the nozzle and the surface to be inkjet printed is determined according to the obtained surface contour, and the inkjet printing track and the surface of the special-shaped product always maintain a preset distance. The coating deposition amount difference caused by the distance change between the nozzle and the product surface is effectively solved, and the uniform distribution of the coating thickness in different areas is realized.

Description

Technical Field

[0001] This invention relates to the field of inkjet printing technology, and in particular to a method, apparatus and system for surface printing on irregularly shaped products. Background Technology

[0002] In modern industrial manufacturing, inkjet printing technology for coating irregularly shaped products has been widely used. This technology aims to impart specific functional or decorative coatings to products with unique shapes and complex structures to meet diverse market demands. With continuous technological advancements, inkjet printing technology has achieved significant progress in terms of precision, speed, and material adaptability.

[0003] However, despite these advancements, some unavoidable technical challenges remain. In the actual process of coating printing on irregularly shaped products, the varying surface shapes, curvatures, uneven structures, and angles make it difficult to maintain a constant distance and angle between the printhead and the product surface. This results in differences in coating deposition across different areas, leading to uneven coating thickness on irregularly shaped products. For example, in curved areas, the distance between the printhead and the surface may suddenly increase, causing the coating to be sprayed in a dispersed manner and resulting in a thinner coating; while in recessed areas, the distance between the printhead and the surface decreases, allowing the coating to accumulate more easily and increasing its thickness.

[0004] This uneven surface coating thickness severely impacts product quality and performance. Uneven coating thickness can lead to cosmetic defects, affecting the product's aesthetic appeal; in terms of functional coatings, it may result in localized areas failing to meet expected standards for protective performance, abrasion resistance, or conductivity, thus reducing product reliability and lifespan. Therefore, resolving the issue of uneven coating thickness on irregularly shaped products is crucial for improving product quality and enhancing market competitiveness, and represents a key technological bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0005] This invention provides a method, apparatus, and system for surface printing on irregularly shaped products, aiming to improve the uniformity of the surface coating on irregularly shaped products.

[0006] On one hand, the present invention proposes a surface printing method for irregularly shaped products, comprising:

[0007] Scan the irregularly shaped product to be printed to determine the surface contour of the irregularly shaped product;

[0008] Based on the surface profile, the printing trajectory between the nozzle and the surface to be printed is determined, and the printing trajectory always maintains a preset distance from the surface of the irregular product.

[0009] The printhead is controlled to print on the surface of the irregularly shaped product along the printing trajectory.

[0010] In some embodiments, scanning the irregularly shaped product to be printed to determine the surface contour of the irregularly shaped product includes:

[0011] The irregularly shaped product is visually scanned to determine its surface contour.

[0012] Alternatively, obtain the drawing file of the irregularly shaped product, and determine the surface contour of the irregularly shaped product based on the drawing file.

[0013] In some embodiments, determining the printing trajectory between the printhead and the surface to be printed based on the surface profile includes:

[0014] Based on the surface contour data, a preset distance is determined between the nozzle and the surface to be sprayed on the irregularly shaped product;

[0015] Obtain multiple contour coordinates corresponding to the surface contour, each contour coordinate including coordinate information corresponding to different positions of the irregular product;

[0016] Based on preset conversion rules, the multiple contour coordinates are converted into corresponding printing trajectories according to the preset distance.

[0017] In some embodiments, determining the preset distance between the nozzle and the surface to be sprayed of the irregularly shaped product based on the surface contour data includes:

[0018] Calculate the curvature of the surface profile;

[0019] Based on the curvature of the surface profile, a preset distance is determined between the nozzle and the surface to be sprayed on the irregularly shaped product.

[0020] In some implementations, the step of converting the plurality of contour coordinates into corresponding printing trajectories based on preset conversion rules and the preset distance includes:

[0021] Based on the coordinate information of the target contour coordinates and the preset distance, the trajectory coordinates of the printing position corresponding to the target contour coordinates are calculated, wherein the target contour coordinates are any one of the plurality of contour coordinates;

[0022] Calculate the trajectory angle change of the printing position corresponding to the target contour coordinates based on two adjacent contour coordinates of the target contour coordinates;

[0023] The trajectory coordinates and trajectory angle changes of the printing position corresponding to each contour coordinate are calculated to obtain the printing trajectory corresponding to the irregular product. The distance between each contour coordinate and the corresponding trajectory coordinate is maintained at the same preset distance.

[0024] In some embodiments, the printing trajectory includes multiple printing trajectory segments, each of which includes a feathered area and a non-feathered area;

[0025] The control of the printhead to print on the surface of the irregularly shaped product along the printing trajectory includes:

[0026] The printhead is controlled to sequentially spray ink onto the surfaces corresponding to the multiple printing trajectory segments along the printing trajectory.

[0027] In the non-feathering zone, the printhead is controlled to spray ink onto the surface to be printed corresponding to the printing trajectory segment;

[0028] In the feathering zone, the nozzle is controlled to perform wedge-shaped feathering on the surface to be printed corresponding to the printing trajectory segment, so as to connect every two printing trajectory segments in the multiple printing trajectory segments.

[0029] In some embodiments, the multi-segment printing trajectory segment includes a first printing trajectory segment and a second printing trajectory segment, wherein the first printing trajectory segment is any one of the multi-segment printing trajectory segments, and the second printing trajectory segment is the trajectory segment following the second printing trajectory segment.

[0030] The control of the printhead to perform wedge-shaped feathering processing on the surface to be printed corresponding to the printing trajectory segment includes:

[0031] In the feathering zone of the first printing trajectory segment, the amount of ink sprayed by the printhead onto the surface to be sprayed corresponding to the feathering zone of the first printing trajectory segment is reduced.

[0032] Adjust the relative position of the nozzle and the surface to be sprayed, and take the feathering area of ​​the first printing trajectory segment as the printing starting point to print the second printing trajectory segment;

[0033] At the starting point of the printing process, the amount of ink applied by the printhead to the surface to be printed corresponding to the feathered area of ​​the first printing trajectory segment is increased until the non-feathered area of ​​the second printing trajectory segment is reached.

[0034] In some embodiments, after the step of converting the plurality of contour coordinates into corresponding printing trajectories based on preset conversion rules and the preset distance, the surface printing method for irregularly shaped products further includes:

[0035] Calculate the distance between every two contour coordinates to obtain the first distance;

[0036] Calculate the distance between every two trajectory coordinates to obtain the second distance;

[0037] The speed ratio is determined based on the first distance and the second distance;

[0038] The speed at which the printhead moves to print on the surface of the irregularly shaped product is determined based on the speed ratio.

[0039] Secondly, the present invention also provides a surface printing apparatus for irregularly shaped products, the surface printing apparatus for irregularly shaped products comprising:

[0040] A scanning unit is used to scan the irregularly shaped product to be printed in order to determine the surface contour of the irregularly shaped product.

[0041] The determining unit is used to determine the printing trajectory between the nozzle and the surface to be printed based on the surface contour, wherein the printing trajectory and the surface of the irregular product are always kept at a preset distance.

[0042] A control unit is used to control the printhead to print on the surface of the irregularly shaped product along the printing trajectory.

[0043] Thirdly, the present invention also proposes a surface printing system for irregularly shaped products. This surface printing system for irregularly shaped products includes a memory and a processor. The memory stores a computer program, and the processor invokes the computer program to implement the steps of the surface printing method for irregularly shaped products disclosed in this application.

[0044] In this embodiment, the surface contour of the irregular product to be printed can be determined by scanning the irregular product to be printed; based on the surface contour, the printing trajectory between the printhead and the surface to be printed is determined, and the printing trajectory always maintains a preset distance from the surface of the irregular product; the printhead is controlled to print on the surface of the irregular product along the printing trajectory.

[0045] The beneficial effects of this invention are as follows: First, by scanning the irregularly shaped product to be printed to determine its surface contour, the shape characteristics of the product surface can be accurately obtained, including information such as various curvatures, concave and convex structures, and angle changes. This provides an accurate data basis for subsequent printing trajectory planning, thereby avoiding the problem of uneven coating caused by blindly printing without knowing the product shape. The printing trajectory between the printhead and the surface to be printed is determined according to the obtained surface contour, and the printing trajectory maintains a preset distance from the surface of the irregularly shaped product at all times. This means that the printhead can adjust its position in real time according to the specific shape of the product surface, ensuring that the distance between the printhead and the product surface remains relatively constant throughout the printing process. In this way, in curved areas, the coating thinning caused by the increased distance between the printhead and the surface to be printed can be controlled; in recessed areas, the distance between the printhead and the surface to be printed can be controlled to prevent coating accumulation caused by too small a distance. Thus, the difference in coating deposition caused by changes in the distance between the printhead and the product surface is effectively solved, and a uniform distribution of coating thickness in different areas is achieved. Controlling the printhead to print along a pre-planned printing trajectory onto the surface of irregularly shaped products ensures the accuracy and stability of the printing process. This allows the coating to cover the product surface evenly, avoiding uneven thickness. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of a printing system provided in an embodiment of the present invention;

[0047] Figure 2 This is a schematic flowchart of a surface printing method for irregularly shaped products according to an embodiment of the present invention.

[0048] Figure 3 This is another schematic flowchart of a surface printing method for irregularly shaped products provided in an embodiment of the present invention.

[0049] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0050] The solutions in 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 a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] It should be noted that the descriptions involving "first," "second," etc., in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0053] To enable those skilled in the art to better understand the solution of this application, the application environment of the solution will first be described. The surface printing method for irregularly shaped products provided in this application can be applied to, for example... Figure 1 In the system architecture shown.

[0054] Please see Figure 1 , Figure 1 This is a schematic diagram of a system architecture for a printing system 100 provided in an embodiment of this application. For example... Figure 1 As shown, the printing system 100 may include a scanning and detection device 101, a work unit 102, and a control processor 103. The control processor 103 can communicate with the scanning and detection device 101 and the work unit 102 respectively.

[0055] The scanning and detection device 101 can be used to scan and detect irregularly shaped products to determine their surface contours. The scanning and detection device 101 can be a device located inside the control processor 103, directly determining the surface contour of the irregularly shaped product through visual scanning. Alternatively, the scanning and detection device 101 can exist independently of the control processor 103, generating CAD drawings, 3D model files, and other drawing documents, and sending the receipt documents to the control processor 103 to confirm the determined surface contour of the irregularly shaped product.

[0056] The printing device 102 may include a printhead, a motion device, an ink supply device, etc. The printing device 102 can complete the printing operation of irregularly shaped products to be printed.

[0057] The control processor 103 possesses powerful computing and data processing capabilities, enabling it to coordinate the operation of various components. It can perform multiple steps, including determining the printing trajectory between the printhead and the surface to be printed based on the surface contour, and controlling the printhead to print along the printing trajectory onto the surface of the irregularly shaped product.

[0058] The above-described inkjet printing system 100 is an example of an inkjet printing system 100 involved in a surface inkjet printing method for irregularly shaped products disclosed in this application. It is intended to better explain the various steps of the surface inkjet printing method for irregularly shaped products when describing the surface inkjet printing method for irregularly shaped products in this application, and does not limit this application.

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0060] This invention proposes a surface printing method for irregularly shaped products.

[0061] Please see Figure 2 , Figure 2 This is a schematic flowchart illustrating a surface printing method for irregularly shaped products disclosed in an embodiment of this application. This surface printing method for irregularly shaped products can be applied to a printing system. Figure 2 As shown, the surface printing method for this irregularly shaped product may include the following steps.

[0062] Step 201: Scan the irregularly shaped product to be printed to determine the surface contour of the irregularly shaped product.

[0063] The surface profile can be the shape and boundary features of the outer surface of an irregularly shaped product. It includes various shape variations such as undulations, bends, and unevenness of the product surface, as well as the transitions between different parts. By describing the surface profile, the external characteristics of the product can be accurately reflected.

[0064] These irregularly shaped products can be those with irregular shapes or those that do not have common standard geometric shapes. These products may have complex and unique shapes, such as special curves, asymmetrical structures, complex three-dimensional shapes, or be composed of multiple different shaped parts.

[0065] It should be noted that scanning irregularly shaped products to be printed can be done using specific scanning technologies or equipment such as lasers or optical sensors. This allows for comprehensive detection and measurement of products with special or irregular shapes to be printed, thereby obtaining information on their surface shape and features, and providing accurate basic data for subsequent printing processes.

[0066] For example, in automobile manufacturing, certain specially shaped parts; in electronic products, non-standard shaped housings, etc., can all be considered irregularly shaped products. Before applying surface coating printing to these products, these specially shaped parts can be scanned to determine their surface contours, so that subsequent printing operations can be performed accurately, ensuring printing quality and effect.

[0067] In some specific implementations, scanning the irregularly shaped product to be printed to determine the surface contour of the irregularly shaped product can be achieved by visually scanning the irregularly shaped product to determine its surface contour.

[0068] It should be noted that in some practical operations, determining the surface contour of an irregularly shaped product to be printed can be achieved by visual scanning of the product. Visual scanning typically involves using optical equipment and related image processing technology to photograph, measure, and analyze the surface of the irregularly shaped product, thereby obtaining detailed information about its shape, size, curvature, etc., to accurately depict the surface contour of the product.

[0069] For example, high-precision industrial cameras, laser scanners, and other equipment can be used to photograph or scan irregularly shaped products from different angles. The acquired data is then processed and calculated using computer software to generate a contour model or data that accurately reflects the product's surface shape. This visual scanning method has advantages such as being non-contact, fast, and accurate, effectively acquiring the complex surface features of irregularly shaped products and providing a reliable basis for subsequent printing work.

[0070] Alternatively, in some other specific implementations, scanning the irregularly shaped product to be printed to determine the surface contour of the irregularly shaped product can also be done by obtaining a drawing file of the irregularly shaped product and determining the surface contour of the irregularly shaped product based on the drawing file.

[0071] It should be noted that in some practical operations, to determine the surface contour of the irregularly shaped product to be printed, it is also possible to obtain a drawing file of the irregularly shaped product and then determine its surface contour based on this drawing file. This drawing file can be a detailed design drawing of the irregularly shaped product created using professional drawing software or design tools. The drawing file can include a two-dimensional plan view, a three-dimensional model view of the irregularly shaped product, and precise information such as dimensions, shapes, and angles.

[0072] For example, CAD drawings and 3D model files generated during the product design phase can be used as drawing files. By reading and analyzing the data in these drawings, surface contour information about irregularly shaped products can be directly obtained without additional measurement or scanning work. This method can save time and cost in determining the surface contour and improve work efficiency when complete and accurate drawing files are already available.

[0073] Step 202: Determine the printing trajectory between the printhead and the surface to be printed based on the surface profile.

[0074] The printing trajectory always maintains a preset distance from the surface of the irregularly shaped product.

[0075] The printing trajectory can be the path followed by the printhead during the printing operation, and the printing trajectory can be a trajectory that maintains the same preset distance as the surface contour of the irregular product.

[0076] It should be noted that, based on the surface contour shape and features of the irregularly shaped product obtained through scanning, the specific route that the printhead should move when performing a printing operation on the product surface can be planned and calculated.

[0077] The preset distance can be a pre-set interval between the printhead and the surface to be printed. This preset distance can be a distance value determined based on the curvature of the irregularly shaped product's surface contour. It can also be the distance value used for surface printing on irregularly shaped products with different surface contours to achieve a preset printing effect.

[0078] It's important to note that when dealing with surfaces with significant curvature, if the preset distance is too small, the paint sprayed from the nozzle may become overly concentrated in localized areas, resulting in an excessively thick and clumped coating, affecting the uniformity and quality of the print. Conversely, if the preset distance is too large, the paint may become excessively dispersed upon reaching the surface, resulting in a thinner coating that may not achieve the desired coverage. On the other hand, for relatively flat surfaces with less curvature, appropriately reducing the preset distance allows for a more concentrated and even distribution of the paint, forming a coating of moderate thickness. However, if the preset distance is too small, clumping may still occur; if the preset distance is too large, the coating may become too thin.

[0079] In some embodiments, determining the printing trajectory between the printhead and the surface to be printed based on the surface profile can be achieved by determining a preset distance between the printhead and the surface to be printed based on the surface profile after determining the surface profile of the irregularly shaped product. After determining the preset distance, the printing trajectory between the printhead and the surface to be printed corresponding to the surface profile is determined based on the preset distance.

[0080] Step 203: Control the printhead to print on the surface of the irregular product along the printing trajectory.

[0081] After determining the printing trajectory, printing can be performed on the surface of the irregularly shaped product according to the printing trajectory. Specifically, after determining the printing trajectory for the surface contour of the irregularly shaped product and the preset distance between the printing trajectory and the surface to be printed, the printhead can be precisely controlled to move according to the printing trajectory and perform the printing operation during the movement.

[0082] For example, the printing process for an irregularly shaped product resembling an olive can be achieved by scanning its surface contour, which reveals that the two ends are pointed and the middle is rounded. For this surface contour, the determined printing trajectory might start from the pointed end and gradually move towards the middle along the surface's curvature. At the pointed end, due to the greater surface curvature, the preset distance might be set to a smaller value, such as 5 cm, to ensure that the paint sprayed from the printhead accurately covers the pointed area, avoiding excessive paint dispersion and a thinner coating. When the printhead moves to the rounded middle section, due to the relatively flat surface and smaller curvature, the preset distance might be adjusted to 8 cm, allowing the paint to be evenly distributed in this area, preventing paint accumulation and an excessively thick coating. Throughout the entire printing trajectory, the preset distance, set according to the surface contour characteristics of that location, is maintained at different positions on the product surface, thereby achieving a uniform and accurate printing effect.

[0083] For example, consider printing on an irregularly shaped part with a complex, uneven structure. On raised sections with greater surface curvature, a preset distance of 4 cm is used to ensure the paint is concentrated and covers the raised area. On recessed sections, the preset distance might be increased to 6 cm to prevent excessive paint concentration and an overly thick coating. The printhead moves along the designed trajectory, maintaining the corresponding preset distance at each position to achieve high-quality printing.

[0084] exist Figure 2 In the described method embodiment, the surface contour of the irregularly shaped product to be printed is determined by scanning the product. Based on the surface contour, the printing trajectory between the printhead and the surface to be printed is determined, and this printing trajectory maintains a preset distance from the surface of the irregularly shaped product. The printhead is then controlled to print on the surface of the irregularly shaped product along the printing trajectory. Thus, the printing trajectory between the printhead and the surface to be printed is determined based on the obtained surface contour, and the printing trajectory maintains a preset distance from the surface of the irregularly shaped product. This effectively solves the problem of coating deposition differences caused by variations in the distance between the printhead and the product surface, achieving a uniform distribution of coating thickness in different areas. Controlling the printhead to print on the surface of the irregularly shaped product along the planned printing trajectory ensures the accuracy and stability of the printing process. This allows the coating to uniformly cover the product surface, avoiding uneven thickness.

[0085] Please see Figure 3 , Figure 3This is a schematic flowchart of another surface inkjet printing method for irregularly shaped products disclosed in an embodiment of this application. This surface inkjet printing method for irregularly shaped products can be applied to chip testing systems. Figure 3 As shown, the surface printing method for this irregularly shaped product may include the following steps.

[0086] Step 301: Scan the irregularly shaped product to be printed to determine the surface contour of the irregularly shaped product.

[0087] The specific details of step 301 can be found in the explanation of step 201, and will not be repeated here.

[0088] Step 302: Determine the preset distance between the nozzle and the surface to be sprayed on the irregularly shaped product based on the surface contour data.

[0089] The preset distance can be a preset distance determined based on the surface contour data of the irregular product. The preset distance can be the distance maintained by the printhead when it is printing on the surface of the irregular product.

[0090] This data information can be the surface contour feature information of the irregularly shaped product, which can include detailed feature information such as the surface shape, curvature, and unevenness of the irregularly shaped product. This data information can be used to calculate the preset distance between the printhead and the surface to be printed in order to achieve a uniform and accurate printing effect at different positions.

[0091] It should be noted that for irregularly shaped products with different surface shapes, curvatures, or unevenness, a predetermined distance between the nozzle and the surface to be sprayed on the irregularly shaped product can be set based on the surface contour data of that irregularly shaped product.

[0092] As an example, determining the preset distance between the nozzle and the surface to be sprayed on the irregularly shaped product based on the surface profile data may include: calculating the curvature of the surface profile; and determining the preset distance between the nozzle and the surface to be sprayed on the irregularly shaped product based on the curvature of the surface profile.

[0093] Among them, the curvature of the surface contour of irregularly shaped products is negatively correlated with the preset distance.

[0094] Specifically, when the surface contour has a large curvature, it means the surface is highly curved. To ensure the uniformity and accuracy of printing, the preset distance usually needs to be set relatively small. This allows the printhead to be closer to the surface, reducing paint dispersion during spraying and ensuring sufficient paint deposition even in areas with high curvature, preventing the coating from becoming thin. Conversely, when the surface contour has a small curvature, i.e., the surface is relatively flat, the preset distance can be appropriately increased. In this case, even with a slightly greater distance between the printhead and the surface, the spraying and distribution of paint can still be relatively uniform, without excessive concentration or accumulation. By reasonably determining this preset distance, the distribution of paint sprayed from the printhead on the product surface can be effectively controlled, reducing uneven coating thickness and improving printing quality.

[0095] For example, for an irregularly shaped sphere, the preset distance should be smaller in the area with a large curvature at the top of the sphere, while the preset distance can be larger in the relatively flat area near the center of the circle.

[0096] Step 303: Obtain multiple contour coordinates corresponding to the surface contour.

[0097] Each contour coordinate includes coordinate information corresponding to different positions on the irregularly shaped product.

[0098] The contour coordinates can be the coordinate information corresponding to any number of points on the surface contour of the irregularly shaped product. These points can be randomly determined points on the surface contour, or they can be contour key points on the surface contour.

[0099] These contour key points are specific points on the surface contour that have significant characteristics or importance, and can significantly affect the overall shape and structure of the product. They are representative of the geometric features of the product surface, and the contour shape of the product can be roughly outlined through these points. For example, the vertices of a curved surface, the endpoints of an edge, and the extreme points of concave or convex parts. For example, for an irregularly shaped product resembling a cone, its vertex and the edge points of the base circle can be regarded as contour key points; for a part with a complex curved surface, the point where the curvature of the surface changes abruptly may be a contour key point.

[0100] Step 304: Based on the preset conversion rules and according to the preset distance, convert multiple contour coordinates into corresponding printing trajectories.

[0101] The conversion rule can be a formula used to convert multiple obtained contour coordinates from points to lines.

[0102] It should be noted that this conversion rule can convert any one of multiple contour coordinates into the coordinates and angle information of a trajectory path using predetermined product contour coordinates. Specifically, the converted contour coordinates can be determined by calculating the angle difference between each contour coordinate and the reference point coordinates, and combining this with the modulus of each contour coordinate, and then the corresponding trajectory angle change can be calculated. After determining the converted contour coordinates and trajectory angle change, the corresponding trajectory path can be calculated based on the trajectory coordinates and trajectory angle changes corresponding to multiple contour coordinates. This trajectory path can be the printing trajectory for printing on irregularly shaped products.

[0103] After scanning the surface of the irregularly shaped product to be printed, a series of multiple contour coordinates can be obtained, such as (X1, Z1), (X2, Z2), (X3, Z3), etc. Then, these contour coordinates are calculated and transformed using preset transformation rules. In the transformation process, the preset distance plays a crucial role. The preset distance determines the desired distance between the printhead and the product surface during printing, and this distance affects the transformed trajectory coordinate values. For example, for a specific contour coordinate (Xn, Zn), the corresponding trajectory coordinate position (xn, zn) and the corresponding angle change information cn are calculated according to the transformation formula. The coordinate information and angle information of this trajectory coordinate constitute a trajectory coordinate (xn, zn, cn) on the printing trajectory. After performing this transformation and processing on all contour coordinates, a complete printing trajectory that meets the preset distance requirements can be obtained.

[0104] In some specific implementations, converting multiple contour coordinates into corresponding printing trajectories based on preset conversion rules and according to preset distances may include:

[0105] (1) Calculate the trajectory coordinates of the printing position corresponding to the target contour coordinates based on the coordinate information of the target contour coordinates and the preset distance. The target contour coordinates can be any one of multiple contour coordinates.

[0106] Here, the trajectory coordinates can be the coordinate values ​​of any position along the printing trajectory of the printhead during the printing process on the irregularly shaped product. These trajectory coordinates can correspond to the outline coordinates. Each outline coordinate can have a corresponding trajectory coordinate, and the correspondence between each outline coordinate and its corresponding trajectory coordinate can be based on coordinate value transformations in different coordinate systems. The difference between the trajectory coordinates and the outline coordinates is based on the expected ink thickness and the height of the printhead.

[0107] It should be noted that the trajectory coordinates of the printing position corresponding to the target contour coordinates are calculated based on the coordinate information of the target contour coordinates and the preset distance by transforming the coordinates of the target contour to another coordinate system in order to determine the printing trajectory that extends outward from the surface to be printed on the irregularly shaped product at a certain preset distance.

[0108] (2) Calculate the trajectory angle change of the printing position corresponding to the target contour coordinate based on the two adjacent contour coordinates of the target contour coordinate.

[0109] The trajectory angle change can be the change in angle formed by the direction of printhead movement when moving from the target contour coordinate position to its two adjacent contour coordinate positions in the printing trajectory.

[0110] It's important to note that after determining multiple contour coordinates, the two adjacent contour coordinates to the left and right of the target contour coordinate can be identified. By analyzing the relative positional relationship between these three coordinates, the angle change in the printhead's movement direction during the printing process, as the printhead moves from the two adjacent coordinates to the target coordinate, can be calculated. This allows for more precise planning of the printhead's movement path (printing trajectory). Because the surface shape is irregular when printing on irregularly shaped products, the printhead needs to continuously adjust its movement direction according to surface variations. By calculating the trajectory angle changes, the angle adjustments required by the printhead at each position can be predicted in advance, ensuring the printing trajectory more closely matches the product surface contour and guaranteeing printing quality and accuracy.

[0111] (3) Calculate the trajectory coordinates and trajectory angle changes of the printing position corresponding to each contour coordinate to obtain the printing trajectory corresponding to the irregular product. The distance between each contour coordinate and the corresponding trajectory coordinate is maintained at the same preset distance.

[0112] For all the obtained contour coordinates of the irregular product surface, the trajectory coordinates and trajectory angle changes are calculated as described in steps (1) and (2) above. The trajectory coordinates and trajectory angle changes corresponding to each contour coordinate are obtained. The relevant data of all points are integrated to form a complete printing path that can accurately cover the surface of the irregular product.

[0113] Specifically, the printing trajectory corresponding to the irregular product can be calculated by calculating the trajectory coordinates corresponding to each contour coordinate, and then determining the corresponding printing trajectory based on these multiple trajectory coordinates.

[0114] For example, multiple contour coordinates can be defined as (X1,Z1), (X2,Z2), (X3,Z3), etc. It is known that each contour coordinate has a corresponding trajectory coordinate. The multiple trajectory coordinates corresponding to these multiple contour coordinates can be initially defined as unknown (x1,y1,z1), (x2,y2,z2), (x3,y3,z3), etc., with a preset distance of d.

[0115] Multiple contour coordinates can be converted into corresponding trajectory coordinates. These trajectory coordinates can include the coordinate position and angle change information of the trajectory coordinates. The conversion formula is as follows:

[0116] x1=COS(ATAN2(X1,Z1)-ATAN2((X2-X0),(Z2-Z0)))*SQRT(X1 2 +Z1 2 )

[0117] z1=-SIN(ATAN2(X1,Z1)-ATAN2((X2-X0),(Z2-Z0)))*SQRT(X1 2 +Z1 2 )

[0118] c1=180(1-ATAN2((X2-X0),(Z2-Z0)) / π)

[0119] Where (x1, z1) are the coordinates of the transformed trajectory coordinates in different dimensions, and c1 can be the angle change information determined after the trajectory coordinates are transformed and calculated.

[0120] By analogy, the trajectory coordinates and trajectory angle changes of all contour coordinates are calculated, and finally the complete printing trajectory is obtained.

[0121] For example, calculating the trajectory coordinates and trajectory angle changes corresponding to a certain contour coordinate may include the following steps: Assume X0 = 0, Z0 = 0, X1 = 3, Z1 = 4, X2 = 6, Z2 = 8.

[0122] First, calculate ATAN2(X1,Z1) and ATAN2((X2-X0),(Z2-Z0)): ATAN2(X1,Z1)=ATAN2(3,4)≈0.927; ATAN2((X2-X0),(Z2-Z0))=ATAN2(6,8)≈0.927. Then calculate X1 and Z1: X1=COS(0.927-0.927)*SQRT(3^2+4^2)=COS(0)*5=5; Z1=-SIN(0.927-0.927)*SQRT(3^2+4^2)=-SIN(0)*5=0. Finally, calculate C1: C1=180*(1-0.927 / π)≈32.7°, and finally determine the corresponding trajectory coordinates as (5,0,32.7°).

[0123] Step 305: Control the printhead to sequentially spray ink onto the surfaces to be printed along the printing trajectory segments.

[0124] The printing trajectory may include multiple printing trajectory segments, and the number of these multiple printing trajectory segments can be determined based on the curvature, unevenness, and other characteristics of the printing trajectory.

[0125] It should be noted that since the printing trajectory corresponds to the surface of the irregularly shaped product, and is a curve corresponding to that surface, the curvature of this curve is positively correlated with the number of trajectory segments. A greater curvature allows the trajectory to be divided into as many segments as possible, improving printing quality. Conversely, a smaller curvature allows for overall printing of the entire trajectory.

[0126] In some implementations, after determining the printing trajectory, the printing trajectory can be divided into multiple printing trajectory segments.

[0127] It should be noted that dividing the printing trajectory into multiple segments can better adapt to the complex variations on the product surface. For example, the product surface may have areas of varying heights, parts with significant curvature changes, or locations requiring different printing precision. By dividing the trajectory appropriately, more targeted printing parameters can be set for each segment, such as printhead movement speed, ink volume, and preset distance.

[0128] Specifically, the division can be based on the geometric features of the surface, such as curvature, slope, and unevenness; or on differences in printing requirements, such as the need for a thicker coating or higher color accuracy in certain areas. Dividing the printing trajectory into multiple segments helps to achieve a finer, more accurate, and more efficient printing process, thereby improving product quality and production efficiency.

[0129] After determining the multiple printing trajectory segments, the printhead can be controlled to perform inkjet operations on the surfaces to be printed, corresponding to the multiple different printing trajectory segments, in order to achieve complete and accurate printing on the entire irregular product surface.

[0130] For example, suppose the printing path on the surface of an irregularly shaped product is divided into three segments: the first segment is the curved top part of the product, the second segment is the sloping side part, and the third segment is the flat bottom part. The control system will first guide the printhead to spray ink along the first segment, then spray ink along the second segment, and finally the third segment, thus ensuring that the entire product surface is uniformly and accurately printed with the desired pattern or coating.

[0131] Step 306: In the non-feathered area, control the printhead to spray ink onto the surface to be printed corresponding to the printing trajectory segment.

[0132] It should be noted that after dividing the printing trajectory, at the junction between each two printing trajectory segments, the printing process will cause differences in parameters such as printhead movement speed, ink volume, or preset distance, resulting in inconsistent coating thickness between the two printing trajectory segments. Therefore, the printing trajectory during the printing operation can be divided into corresponding feathered and non-feathered areas to perform inkjet printing on irregularly shaped products with trays based on the different area divisions of the printing trajectory.

[0133] The non-feathered area is the region corresponding to the edge area in each segment of the printing trajectory after the printing trajectory is segmented.

[0134] In the non-feathered area of ​​each printing trajectory segment, the printhead can be directly controlled to perform inkjet operation on the corresponding surface to be printed along the printing trajectory segment.

[0135] Step 307: In the feathering zone, control the printhead to perform wedge-shaped feathering on the surface to be printed corresponding to the printing trajectory segment, so as to connect every two printing trajectory segments in the multiple printing trajectory segments.

[0136] The feathering zone can be the connecting area between every two printing trajectory segments. The feathering zone usually refers to the area in the printing area that needs to be specially treated so that the printing effect gradually transitions from clear and obvious to blurry and soft.

[0137] When the printhead's printing area enters the surface to be printed corresponding to the feathering zone, the printhead can be controlled to perform a special treatment on the surface to be printed, namely wedge feathering. The purpose of this treatment is to enable adjacent segments in multiple printing trajectory segments to connect naturally and smoothly, eliminating any obvious boundaries or discontinuities.

[0138] Among them, wedge feathering can be a process in which the ink jetting pattern of the printhead in the feathering zone gradually changes. For example, the ink jetting volume gradually decreases from a large amount, or the printhead moving speed gradually increases from a slow amount, forming a wedge-shaped transition effect. This makes the connection between two adjacent printing trajectory segments smoother and more uniform, improving printing quality and visual effect.

[0139] In some specific implementations, the multi-segment printing trajectory segment may include a first printing trajectory segment and a second printing trajectory segment. The first printing trajectory segment is any one of the multi-segment printing trajectory segments, and the second printing trajectory segment is the trajectory segment following the second printing trajectory segment.

[0140] The step of controlling the printhead to perform wedge feathering treatment on the surface to be printed corresponding to the printing trajectory segment may include: (1) in the feathering area of ​​the first printing trajectory segment, reducing the amount of ink sprayed by the printhead on the surface to be printed corresponding to the feathering area of ​​the first printing trajectory segment.

[0141] In the feathering zone near the end of the first printing trajectory segment, where it connects with the second printing trajectory segment, the ink volume ejected by the printhead can be gradually reduced. Simply put, reducing the ink volume in the feathering zone is a "prelude" to the upcoming transition, causing the color or coating thickness at the end of the first printing trajectory segment to gradually lighten and thin.

[0142] For example, the printhead initially operates with a stable, large ink volume. After the printing area reaches the feathering zone, the ink volume gradually decreases, from 10 ml per second initially to 5 ml per second.

[0143] (2) Adjust the relative position of the nozzle and the surface to be sprayed, and take the feathering area of ​​the first printing trajectory segment as the printing start point to print the second printing trajectory segment.

[0144] After finishing printing the feathered area of ​​the first printing trajectory, the relative position of the printhead and the surface to be printed can be adjusted, and the feathered area of ​​the first printing trajectory segment can be used as a new starting point to start printing the second printing trajectory segment.

[0145] (3) At the starting point of printing, increase the amount of ink on the surface to be printed corresponding to the feathered area of ​​the first printing trajectory segment until the non-feathered area of ​​the second printing trajectory segment.

[0146] By using the feathered area of ​​the first printing trajectory segment as the starting point for the second printing trajectory segment, the ink volume can be gradually increased directly from this starting point. That is, starting from this new starting point, the feathered area of ​​the first printing trajectory segment, the ink volume ejected from the printhead is gradually increased, creating a wedge-shaped transition effect and improving the printing quality from the first printing trajectory segment to the second printing trajectory segment.

[0147] For example, the ink flow rate is gradually increased from 5 ml / s to 10 ml / s until it enters the non-feathered zone of the second printing trajectory segment, achieving a smooth transition in ink flow. This allows the two printing trajectories to connect naturally and smoothly without abrupt boundaries or obvious differences in color or thickness. Thus, through precise control of ink flow and printhead position, wedge-shaped feathering is achieved between printing trajectory segments, improving printing quality and aesthetics.

[0148] In other embodiments, after the step of converting multiple contour coordinates into corresponding printing trajectories based on preset conversion rules and preset distances, the surface printing method for irregularly shaped products further includes: calculating the distance between every two contour coordinates to obtain a first distance; calculating the distance between every two trajectory coordinates to obtain a second distance; determining a speed ratio based on the first distance and the second distance; and determining the movement speed of the printhead on the surface of the irregularly shaped product based on the speed ratio.

[0149] The first distance can refer to the straight-line distance between any two adjacent contour coordinates in the original multiple contour coordinates. This first distance can be used to reflect the actual spacing between contour points on the surface of an irregularly shaped product before the printing trajectory conversion is performed.

[0150] The second distance can be the straight-line distance between every two adjacent trajectory coordinates in the converted printing trajectory. Unlike the first distance, the second distance is the spacing calculated on the trajectory after processing by the conversion rules.

[0151] The speed ratio can be calculated by comparing a first distance with a second distance. The speed ratio can be used to reflect the proportional relationship between the profile coordinate spacing and the trajectory coordinate spacing.

[0152] The movement speed refers to the speed at which the printhead moves when printing on the surface of an irregularly shaped product. This movement speed can be used to determine the movement speed so that the movement of the printhead can adapt to changes in the spacing of the contour and trajectory, thereby achieving uniform and accurate printing.

[0153] It should be noted that the printhead's movement speed is precisely controlled based on the product's original outline and the converted printing trajectory. By calculating the speed ratio between the first and second distances, and then determining the printhead's movement speed based on this ratio, it can be ensured that the printhead can reasonably adjust its movement speed according to changes in surface shape and trajectory during the printing process.

[0154] For example, if the second distance in a certain segment increases relative to the first distance, the speed ratio increases, and the printhead's movement speed in that segment will increase accordingly; conversely, if the second distance decreases, the speed ratio decreases, and the printhead's movement speed will decrease. This avoids underprinting in areas with larger spacing or overprinting in areas with smaller spacing, thereby improving print quality and consistency.

[0155] exist Figure 3 In the described method embodiment, the surface contour of the irregularly shaped product to be printed is determined by scanning the product. Based on the surface contour, the printing trajectory between the printhead and the surface to be printed is determined, and this printing trajectory maintains a preset distance from the surface of the irregularly shaped product. The printhead is then controlled to print on the surface of the irregularly shaped product along the printing trajectory. Thus, the printing trajectory between the printhead and the surface to be printed is determined based on the obtained surface contour, and the printing trajectory maintains a preset distance from the surface of the irregularly shaped product. This effectively solves the problem of coating deposition differences caused by variations in the distance between the printhead and the product surface, achieving a uniform distribution of coating thickness in different areas. Controlling the printhead to print on the surface of the irregularly shaped product along the planned printing trajectory ensures the accuracy and stability of the printing process. This allows the coating to uniformly cover the product surface, avoiding uneven thickness.

[0156] It should be understood that the same or corresponding information in the different embodiments described above can be referenced in relation to each other.

[0157] It should be understood that, although Figure 2 , Figure 3 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 2 and Figure 3 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0158] The above are merely specific embodiments of this application. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for surface printing on irregularly shaped products, characterized in that, include: Scan the irregularly shaped product to be printed to determine the surface contour of the irregularly shaped product; Based on the surface profile, the printing trajectory between the nozzle and the surface to be printed is determined, and the printing trajectory always maintains a preset distance from the surface of the irregular product. Control the printhead to print on the surface of the irregularly shaped product along the printing trajectory; Determining the printing trajectory between the printhead and the surface to be printed based on the surface contour includes: Based on the surface contour data, a preset distance is determined between the nozzle and the surface to be sprayed on the irregularly shaped product; Obtain multiple contour coordinates corresponding to the surface contour, each contour coordinate including coordinate information corresponding to different positions of the irregular product; Based on preset conversion rules, the multiple contour coordinates are converted into corresponding printing trajectories according to the preset distance; The method based on preset conversion rules, according to the preset distance, converts the multiple contour coordinates into corresponding printing trajectories, including: Based on the coordinate information of the target contour coordinates and the preset distance, the trajectory coordinates of the printing position corresponding to the target contour coordinates are calculated, wherein the target contour coordinates are any one of the plurality of contour coordinates; Calculate the trajectory angle change of the printing position corresponding to the target contour coordinates based on two adjacent contour coordinates of the target contour coordinates; Calculate the trajectory coordinates and trajectory angle changes of the printing position corresponding to each contour coordinate to obtain the printing trajectory corresponding to the irregular product. The distance between each contour coordinate and the corresponding trajectory coordinate is maintained at the same preset distance. Determining the preset distance between the nozzle and the surface to be sprayed of the irregularly shaped product based on the surface contour data includes: Calculate the curvature of the surface profile; Based on the curvature of the surface profile, a preset distance is determined between the nozzle and the surface to be sprayed on the irregularly shaped product; The curvature of the surface contour of the irregularly shaped product is negatively correlated with the preset distance.

2. The surface printing method for irregularly shaped products according to claim 1, characterized in that, The scanning of the irregularly shaped product to be printed, to determine the surface contour of the irregularly shaped product, includes: The irregularly shaped product is visually scanned to determine its surface contour. Alternatively, obtain the drawing file of the irregularly shaped product, and determine the surface contour of the irregularly shaped product based on the drawing file.

3. The surface printing method for irregularly shaped products according to claim 1, characterized in that, The printing trajectory includes multiple printing trajectory segments, and each printing trajectory segment includes a feathered area and a non-feathered area; The control of the printhead to print on the surface of the irregularly shaped product along the printing trajectory includes: The printhead is controlled to sequentially spray ink onto the surfaces corresponding to the multiple printing trajectory segments along the printing trajectory. In the non-feathering zone, the printhead is controlled to spray ink onto the surface to be printed corresponding to the printing trajectory segment; In the feathering zone, the nozzle is controlled to perform wedge-shaped feathering on the surface to be printed corresponding to the printing trajectory segment, so as to connect every two printing trajectory segments in the multiple printing trajectory segments.

4. The surface printing method for irregularly shaped products according to claim 3, characterized in that, The multi-segment printing trajectory segment includes a first printing trajectory segment and a second printing trajectory segment. The first printing trajectory segment is any one of the multi-segment printing trajectory segments, and the second printing trajectory segment is the trajectory segment following the second printing trajectory segment. The control of the printhead to perform wedge-shaped feathering processing on the surface to be printed corresponding to the printing trajectory segment includes: In the feathering zone of the first printing trajectory segment, the amount of ink sprayed by the printhead onto the surface to be sprayed corresponding to the feathering zone of the first printing trajectory segment is reduced. Adjust the relative position of the nozzle and the surface to be sprayed, and take the feathering area of ​​the first printing trajectory segment as the printing starting point to print the second printing trajectory segment; At the starting point of the printing process, the amount of ink applied by the printhead to the surface to be printed corresponding to the feathered area of ​​the first printing trajectory segment is increased until the non-feathered area of ​​the second printing trajectory segment is reached.

5. The surface printing method for irregularly shaped products according to any one of claims 1 to 4, characterized in that, After the step of converting the multiple contour coordinates into corresponding printing trajectories based on preset conversion rules and the preset distance, the surface printing method for irregularly shaped products further includes: Calculate the distance between every two contour coordinates to obtain the first distance; Calculate the distance between every two trajectory coordinates to obtain the second distance; The speed ratio is determined based on the first distance and the second distance; The speed at which the printhead performs printing on the surface of the irregularly shaped product is determined based on the speed ratio. The speed ratio is a ratio calculated by comparing the first distance with the second distance; the speed ratio is used to reflect the proportional relationship between the contour coordinate spacing and the trajectory coordinate spacing.

6. A surface printing device for irregularly shaped products, characterized in that, include: A scanning unit is used to scan the irregularly shaped product to be printed in order to determine the surface contour of the irregularly shaped product. The determining unit is used to determine the printing trajectory between the nozzle and the surface to be printed based on the surface contour, wherein the printing trajectory and the surface of the irregular product are always kept at a preset distance. A control unit is used to control the printhead to print on the surface of the irregularly shaped product along the printing trajectory. The step of determining the printing trajectory between the printhead and the surface to be printed based on the surface contour includes: Based on the surface contour data, a preset distance is determined between the nozzle and the surface to be sprayed on the irregularly shaped product; Obtain multiple contour coordinates corresponding to the surface contour, each contour coordinate including coordinate information corresponding to different positions of the irregular product; Based on preset conversion rules, the multiple contour coordinates are converted into corresponding printing trajectories according to the preset distance; The method based on preset conversion rules, according to the preset distance, converts the multiple contour coordinates into corresponding printing trajectories, including: Based on the coordinate information of the target contour coordinates and the preset distance, the trajectory coordinates of the printing position corresponding to the target contour coordinates are calculated, wherein the target contour coordinates are any one of the plurality of contour coordinates; Calculate the trajectory angle change of the printing position corresponding to the target contour coordinates based on two adjacent contour coordinates of the target contour coordinates; Calculate the trajectory coordinates and trajectory angle changes of the printing position corresponding to each contour coordinate to obtain the printing trajectory corresponding to the irregular product. The distance between each contour coordinate and the corresponding trajectory coordinate is maintained at the same preset distance. Determining the preset distance between the nozzle and the surface to be sprayed of the irregularly shaped product based on the surface contour data includes: Calculate the curvature of the surface profile; Based on the curvature of the surface profile, a preset distance is determined between the nozzle and the surface to be sprayed on the irregularly shaped product; The curvature of the surface contour of the irregularly shaped product is negatively correlated with the preset distance.

7. A surface printing system for irregularly shaped products, characterized in that, The surface printing system for irregularly shaped products includes a memory and a processor. The memory stores a computer program, and the processor calls the computer program to implement the steps of the surface printing method for irregularly shaped products as described in any one of claims 1 to 6.

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