A printing processing method and device of a sand mold 3D printing equipment and related equipment

Abstract

This invention discloses a printing processing method, apparatus, and related equipment for sand mold 3D printing, relating to the field of sand mold 3D printing technology, to solve the efficiency problem of existing sand mold 3D printing technologies. The method includes: acquiring sand casting product information of the sand casting product to be printed; slicing the STL format 3D model to obtain CLI format slice files; converting the CLI format slice files into corresponding PRT format image files, and, while using the sand spreader in the sand mold 3D printing equipment for sand spreading, processing the PRT format image files based on a preset fractional frequency division method of the grating signal to complete the printing; determining the actual sand casting size of the sand casting product after printing, and determining a scaling factor based on the actual sand casting size and the designed sand casting size; processing the CLI format slice files based on the scaling factor to obtain a target PRT format image file, and processing the target PRT format image file for printing. This improves printing efficiency.

Description

Technical Field

[0001] This invention relates to the field of sand mold 3D printing technology, and in particular to a printing process method, apparatus and related equipment for sand mold 3D printing equipment. Background Technology

[0002] To improve printing efficiency, the foundry industry now widely uses sand mold 3D inkjet printing equipment. 3D inkjet printing technology combines inkjet printing and 3D printing, enabling the precise and efficient fabrication of complex materials in three-dimensional space. Its unique working principle and wide applicability demonstrate its enormous application potential, making it a crucial engine for driving innovation in new materials.

[0003] In existing technologies, when using sand mold 3D printing equipment, it is often necessary to first generate a 3D model of the sand-cast product to be printed in a fixed format according to user requirements, and then slice it. After slicing, sand is laid and ink is sprayed layer by layer according to the specifications of the slices. The process of laying sand and spraying ink is repeated layer by layer until the 3D inkjet printing is completed. When it is necessary to adjust the size of the printed 3D product, the 3D model is usually regenerated and sliced ​​again, making the printing process cumbersome and inefficient.

[0004] It is evident that improving the efficiency of 3D inkjet printing is a pressing technical issue that needs to be addressed. Summary of the Invention

[0005] The purpose of this invention is to provide a printing process method, apparatus and related equipment for sand mold 3D printing equipment, which improves the printing efficiency of sand mold 3D printing equipment.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a printing process method for a sand mold 3D printing device, comprising:

[0008] Obtain sand casting product information for the sand casting product to be printed; the sand casting product information includes at least an STL format 3D model corresponding to the sand casting product to be printed and the designed sand casting dimensions;

[0009] The STL format 3D model is sliced ​​to obtain a CLI format slice file; the CLI format slice file includes N layers of CLI format slices; where N is a positive integer greater than 2;

[0010] The CLI format slice file is converted into the corresponding PRT format image file, and when sand is laid using the sand spreader in the sand mold 3D printing equipment, the PRT format image file is printed based on the preset grating signal fractional frequency division method to complete the printing.

[0011] Determine the actual sand casting size of the sand casting product after printing, and determine the scaling factor based on the actual sand casting size and the designed sand casting size;

[0012] The CLI format slice file is processed based on the scaling factor to obtain the target PRT format image file, and the target PRT format image file is then printed.

[0013] Optionally, the process of processing the CLI format slice file based on the scaling factor to obtain the target PRT format image file includes:

[0014] Parse all vector elements in the CLI format slice file;

[0015] Based on the scaling factor, each vector element in all vector elements is processed to obtain the target PRT format image file.

[0016] Optionally, the step of processing each vector element among all vector elements based on the scaling factor to obtain the target PRT format image file includes:

[0017] Multiply the dot matrix coordinates obtained by splitting each vector element by the scaling factor to obtain the scaled dot matrix value;

[0018] The scaled bit values ​​are filled and drawn onto an RPT format image to obtain the target PRT format image file.

[0019] Optionally, the PRT format image file includes N PRT format image sub-files corresponding to the N layers of the CLI format slices;

[0020] The printing process of the PRT format image file based on the preset fractional frequency division method of the grating signal and the sand spreader in the sand mold 3D printing equipment includes:

[0021] Determine the frequency division ratio based on printing requirements;

[0022] When sand is spread using the sand spreader, the printing carriage in the sand mold 3D printing equipment is controlled based on the frequency division ratio to spray the binder onto the sand casting product to be printed, thereby completing the printing of each PRT format image sub-file.

[0023] Optionally, determining the frequency division ratio according to printing requirements includes:

[0024] Determine the initial resolution and target resolution of the sand casting product to be printed;

[0025] The frequency division ratio is determined based on the initial resolution and the target resolution.

[0026] Optionally, determining the frequency division ratio based on the initial resolution and the target resolution includes:

[0027] Calculate the greatest common divisor of the initial resolution and the target resolution;

[0028] Substituting the greatest common divisor and the target resolution into the formula:

[0029] ;

[0030] The frequency division ratio is calculated; wherein, The frequency division ratio is... The target resolution. The greatest common divisor is denoted as .

[0031] Alternatively, the printing process of the sand mold 3D printing equipment also includes:

[0032] When printing the current PRT format image sub-file, the next CLI format slice is converted to obtain the next PRT format image sub-file corresponding to the next CLI format slice.

[0033] Compared with existing technologies, the present invention provides a printing processing method for sand mold 3D printing equipment. After slicing the STL format 3D model, the CLI format slice file is converted into a corresponding PRT format image file. In this way, when there is a difference between the actual sand casting size of the printed product and the designed sand casting size, the CLI format slice file can be directly adjusted by scaling factor, without having to readjust the original 3D model and then slice it again as in traditional technology. This greatly improves printing efficiency. In addition, a preset raster signal fractional frequency division method is used in the printing process, which improves printing accuracy and reduces the number of repeated printing adjustments, further improving printing efficiency.

[0034] Secondly, the present invention provides a printing processing apparatus for a sand mold 3D printing device, comprising:

[0035] The acquisition module is used to acquire sand casting product information of the sand casting product to be printed; the sand casting product information includes at least the STL format three-dimensional model corresponding to the sand casting product to be printed and the designed sand casting dimensions.

[0036] The slicing module is used to slice the STL format 3D model to obtain a CLI format slice file; the CLI format slice file includes N layers of CLI format slices; where N is a positive integer greater than 2;

[0037] The first processing module is used to convert the CLI format slice file into the corresponding PRT format image file, and when sand is laid using the sand spreader in the sand mold 3D printing equipment, the PRT format image file is printed based on a preset grating signal fractional frequency division method to complete the printing.

[0038] The determination module is used to determine the actual sand casting size of the sand casting product after printing, and to determine the scaling factor based on the actual sand casting size and the designed sand casting size;

[0039] The second processing module is used to process the CLI format slice file based on the scaling factor to obtain the target PRT format image file, and to print the target PRT format image file.

[0040] Thirdly, the present invention provides an electronic device, comprising: a processor, a communication interface, a memory, and a communication bus; wherein the processor, the communication interface, and the memory communicate via the communication bus; the memory stores a computer program executable by the processor; when the processor runs the computer program, it executes the printing process method of the sand mold 3D printing device described in any of the preceding claims.

[0041] Fourthly, the present invention provides a computer storage medium storing instructions that, when executed, implement the printing process method of the sand mold 3D printing equipment described in any of the preceding claims. Attached Figure Description

[0042] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0043] Figure 1 One of the schematic flowcharts of a printing process for a sand mold 3D printing device provided in an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of a frequency division process provided for one embodiment of the present invention;

[0045] Figure 3 A second schematic flowchart of a printing process for a sand mold 3D printing device provided in an embodiment of the present invention;

[0046] Figure 4 A schematic diagram of the printing processing device of a sand mold 3D printing equipment provided in one embodiment of the present invention;

[0047] Figure 5 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present invention. Detailed Implementation

[0048] To facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are merely used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0049] It should be noted that in this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0050] In this invention, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between the associated objects, indicating that three relationships can exist.

[0051] In existing technologies, 3D inkjet printing typically involves first generating a fixed-format 3D model of the sand-cast product to be printed based on user requirements, and then slicing it. After slicing, sand is laid and ink is sprayed layer by layer according to the slicing specifications. This process of laying sand and spraying ink is repeated until the 3D inkjet printing is complete. When the dimensions of the printed 3D product need to be adjusted, the 3D model is usually regenerated and sliced ​​again, making the printing process cumbersome and inefficient. To solve the above problems, see [reference needed]. Figure 1 This invention provides a printing process method for a sand mold 3D printing device, which may include:

[0052] Step 110: Obtain the sand casting product information of the sand casting product to be printed; the sand casting product information shall include at least the STL format 3D model corresponding to the sand casting product to be printed and the designed sand casting dimensions;

[0053] In one embodiment, the system can receive model files transmitted by users, who may be customers requiring 3D inkjet printing or engineers conducting testing. The model file to be printed is exported to STL format using common CAD software, such as SolidWorks, Creo, and ZBrush. Alternatively, modeling software such as Blender and MeshMixer can be used to directly generate the STL file. After generating the original product model to be printed, it is exported as an STL file. The topology of the STL model file can be checked by relevant personnel or by the software's built-in function. If topology issues are found, they are corrected, and the STL model file is regenerated. This process of checking and correcting is repeated until no topology issues exist. If no topology issues are found, sand casting product information is generated based on the STL model file. The STL model file, i.e., the STL format 3D model corresponding to the sand casting product to be printed, is then input into slicing software for slicing. The topology detection process of the STL model file in this embodiment can improve the success rate of one-time molding from the digital model to the physical sand mold, thereby improving printing efficiency.

[0054] Sand mold 3D printing equipment is a core piece of equipment that uses 3D printing technology to manufacture sand casting molds or sand patterns. It can quickly and accurately produce sand molds with complex shapes, simplifying the casting process.

[0055] The sand mold 3D printing equipment in this embodiment of the invention includes at least components such as a sand spreader, a printing carriage, and a grating signal generator. The printing carriage employs binder jetting technology.

[0056] STL (Stereo Lithography) format is a widely used 3D model file format used to represent the surface geometry of 3D solid models. It discretizes the model surface into a series of small triangular facets, thus approximating the shape of the 3D solid. An STL file consists of a series of triangular facets, each containing three vertex coordinates and a normal vector pointing outwards from the facet. These facets collectively define the surface of the 3D model.

[0057] The STL format contains only geometric information and does not involve advanced attributes such as color and material, so the file format is relatively simple.

[0058] STL files have two main formats: ASCII format and binary format. ASCII format stores triangular facet information in text form, which is easy to read and edit, but the file size is relatively large, making it unsuitable for large-scale data transfer. Binary format stores triangular facet information in binary form, resulting in a smaller file size and faster read speed, making it more suitable for data transfer and storage in practical applications.

[0059] Step 120: Slice the STL format 3D model to obtain a CLI format slice file; the CLI format slice file includes N layers of CLI format slices; where N is a positive integer greater than 2;

[0060] CLI (Common Layer Interface) is a slice file format.

[0061] The CLI format slice file contains printing instructions after slicing the STL format 3D model, such as layer height, infill density, and printing speed. It is used to guide the sand mold 3D printing equipment to build sand casting products layer by layer according to the N-layer CLI format slice.

[0062] Step 120 may specifically include the following steps:

[0063] Step 1: Choose the appropriate slicing software. Slicing software is a tool specifically designed to convert 3D models into slice files that can be recognized by 3D printers. Common slicing software includes Cura, Slic3r, and Simplify3D. These software programs typically support STL format as input and can output slice files in various formats, including CLI format (which may be called by other specific names in some software, but is essentially similar).

[0064] The second step: In the slicing software, you first need to import the 3D model in STL format. This is usually done using the software's "Open" or "Import" function. After importing, the model will be displayed in the software's 3D view, where users can perform operations such as rotation, scaling, and movement for a better viewing experience.

[0065] Step 3: Next, you need to set the slicing parameters. These parameters include layer thickness, printing speed, infill rate, and support structure, which directly affect the quality and effect of 3D printing. Choose appropriate parameters based on actual needs, such as printer performance, material properties, and printing requirements.

[0066] Step 4: After setting the parameters, perform the slicing operation. The slicing software will cut the 3D model into a series of horizontal layers according to the set parameters, and generate a slice file containing printing information for each layer.

[0067] Step 5: After slicing, choose to export the slice file as CLI format (or another similar format supported by the software). When exporting, choose the save path and file name, and ensure the file format is correct. Once the export is successful, the CLI format slice file can be transferred to the 3D printer for printing.

[0068] In an optional embodiment, the STL format model file is input into format conversion software, which may include Autodesk Netfabb, Materialise Magics, and 3DSystems 3DPrint, etc. These software programs output CLI format files in versions CLI 2.0, CLI 1.0, and CLI 1.2, respectively. CLI 1.0 files can be preferred as they are compatible with most industrial equipment on the market. After inputting the STL format model file into the conversion software, the software's built-in automatic repair function can be used to repair the model, or relevant personnel can manually repair it based on experience. After repair, the software receives slicing parameters input by relevant personnel or from the sand casting product information. Slicing parameters include the thickness of each slice, slice contour accuracy, adhesive parameters, interlayer curing time, edge reinforcement spraying times, and designed sand casting dimensions. After obtaining the CLI format slicing file, a trial print can be performed using a printer. Once the print results match the user's requirements, batch printing can proceed, thereby improving printing efficiency.

[0069] Step 130: Convert the CLI format slice file into the corresponding PRT format image file, and when the sand is laid in the sand mold 3D printing equipment, print the PRT format image file based on the preset grating signal fractional frequency division method to complete the printing.

[0070] In one implementation, since the printer can only read PRT format images, the CLI format slice file needs to be converted into the corresponding PRT format image file before being input into the 3D printer for printing. If the personnel have CLI-PRT format conversion RIP software, they can use the built-in function of the existing RIP software to convert the CLI format slice file into the corresponding PRT format image file. Alternatively, the personnel can manually convert the CLI format file layer by layer to obtain the PRT format image.

[0071] This embodiment provides a method for relevant personnel to convert CLI format slice files into PRT format image files. The specific implementation is as follows: Read the CLI format file corresponding to a slice and parse it. First, read the file header of the CLI format file and obtain information such as the actual unit of pixels, model size, creation time, and slice thickness in the file header. The actual unit of pixels is the actual length between the coordinates of adjacent pixels. Next, the geometry section of the CLI file is read. Each layer of the image contains multiple polygonal contours. Each polygonal contour is obtained by the number of points and coordinates of those points in the geometry section file. For example, if the geometry section contains 4; 0, 0; 50, 0; 50, 50; 0, 50; 3; 20, 10; 30, 20; 30, 10, we can determine that the image in that layer has two polygonal contours with 4 and 3 vertices respectively. That is, the polygons are a quadrilateral and a trilateral. The coordinates of the four vertices of the quadrilateral are (0, 0), (50, 0), (50, 50), and (0, 50), and the coordinates of the three vertices of the trilateral are (20, 10), (30, 20), and (30, 10). The geometry section may also contain straight lines formed by two vertices, etc. Further, the color section of the CLI file is read. The color section contains pixel coordinates and their corresponding color information, which is usually stored in RGB format.

[0072] After parsing the CLI format file, the required print resolution and color depth are obtained. A binary image corresponding to this resolution and color depth is generated, with all initial values ​​in the binary image set to 0. Based on the actual pixel units in the CLI header file, the coordinates of the polygon outlines in the geometry section, and the pixel coordinates in the color section, the positions to be filled in the binary image are obtained, and a mapping relationship is established between the coordinates of these positions and the coordinates in the coordinate file. A preset RGB-YMCK conversion template is retrieved, and based on the conversion template, the mapping relationship, and the color information corresponding to the pixel coordinates in the color section, binary filling is performed on the positions to be filled. This results in a PRT format image file.

[0073] Understandably, after converting the CLI format slice file to the corresponding PRT format image file, the PRT format image file includes N PRT format image sub-files corresponding to the N CLI format slices. Therefore, step 130 can specifically include:

[0074] The first step is to determine the frequency division ratio based on the printing requirements. The printing requirements generally involve the resolution of the sand casting product to be printed. The original sand casting product received by the product manufacturer has its own initial resolution, while the actual product printing often has a target resolution.

[0075] The second step: When spreading sand using a sand spreader, the printing carriage in the sand mold 3D printing equipment sprays binder onto the sand casting product to be printed based on the frequency division ratio, thus completing the printing of each PRT format image sub-file.

[0076] The first step can specifically include:

[0077] Step 1: Determine the initial resolution and target resolution of the sand casting product to be printed;

[0078] Step 2: Determine the frequency division ratio based on the initial resolution and the target resolution.

[0079] In step 1, the first step is to understand the initial resolution of the sand-cast product to be printed. This is usually provided by the product designer or manufacturer and reflects the level of detail in the product's original data.

[0080] Secondly, based on printing requirements, determine the target resolution needed for printing the actual product. The target resolution should take into account the product's end use, dimensional accuracy requirements, and the performance limitations of the printing equipment.

[0081] Understandably, the initial resolution can also be determined by the printer's own properties. In this embodiment, the printer typically has a grating ruler along the printhead's movement path to assist in controlling the printhead's movement and firing frequency. During printhead movement, the reader on the printhead reads the position on the grating ruler in real time and feeds the position information back to the host computer. The host computer then controls the printhead to spray ink based on the printhead's position coordinates. The time interval for ink spraying is usually determined by the grating interval at the printer's factory settings, which in turn determines the printhead's firing frequency. Typically, the host computer stores a fixed grating interval on its board at the factory, meaning it stores a fixed printhead firing frequency. Therefore, the printer's firing interval determines the printhead's movement speed. In this embodiment, the grating interval stored on the board is updated, and the grating is further subdivided. This allows for an increase in the firing frequency without changing the movement speed, thereby improving the resolution.

[0082] Therefore, to further improve the printing efficiency of 3D printers, this embodiment provides a method for frequency division of printer printing control. For example, previously, when the printhead moved parallel to the grating for one unit length, there were two feedback signals sent to the board after the grating reader read the motion signal. Each feedback signal triggered one printhead ejection action, meaning that the distance the printhead moved for one unit length contained two ejection control signals. After performing three-segment frequency division on the grating control method, the grating length corresponding to the two adjacent feedback motion signals is divided into one-third of the previous length. Now, when the printhead moves parallel to the grating for one unit length, there are six feedback signals sent to the board after the grating reader reads the motion signal, meaning that the distance the printhead moved for one unit length contains six ejection control signals. It can be seen that after performing three-segment frequency division on the printer, the number of ink ejections per unit length changes from two to six. If the moving speed is not changed, the ink ejection frequency can be increased, thereby improving the printing resolution of 3D printing.

[0083] In existing technologies, increasing print resolution typically requires increasing the number of print passes. The number of print passes refers to the number of times the print carriage with the printhead moves back and forth during the scanning process without stepping. The scan path refers to the path the print carriage takes to print a complete row or column in one pass, while the stepping path is a path perpendicular to the scan path. The print carriage moves back and forth along the scan path according to a preset pass. After completing the scan path, the print carriage steps to the adjacent scan path and continues to move back and forth according to the preset pass.

[0084] Different printing products require different pass-based printing methods. Each additional pass in the scanning process after each step doubles the printing time, and the more passes, the lower the printing efficiency. The frequency division method for the raster signal provided in this embodiment can avoid using a large number of passes for printing, ensuring different resolutions while improving the efficiency of 3D printing.

[0085] In step 2, the division ratio refers to the proportion by which the printing device divides the raster signal when processing an image file. To obtain a clear and accurate print, the division ratio needs to be calculated based on the initial resolution and the target resolution. If the initial resolution is higher than the target resolution, it may be necessary to reduce the resolution through division to accommodate the performance of the printing device. Conversely, if the initial resolution is lower than the target resolution, it may be necessary to increase the resolution through other means (such as interpolation).

[0086] Understandably, after determining the division ratio, some printing parameters, such as sand spreading speed and raster scanning frequency, may be adjusted to ensure that the printing process can accurately print at the set resolution.

[0087] Step 2 may specifically include:

[0088] Calculate the greatest common divisor of the initial resolution and the target resolution;

[0089] Substituting the greatest common divisor and the target resolution into the formula:

[0090] (1)

[0091] The frequency division ratio is calculated; where, It is the frequency division ratio. For the target resolution, It is the greatest common divisor.

[0092] For example, if the initial resolution is 1000 and the target resolution is 2000, their greatest common divisor is 1000. Substituting the target resolution 2000 and the greatest common divisor 1000 into formula (1), we get the frequency division ratio = 2000 / 1000 = 2. For example... Figure 2 As shown, if the frequency division ratio is 2, that is, two signals are inserted into the original grating ruler spacing, so that the frequency of the output signal fout becomes twice the frequency of the input signal fin.

[0093] The above methods can be used to divide the original grating ruler signal (the grating signal initially set in the sand mold 3D printing equipment) by frequency. For example, if the original grating ruler signal spacing is 1mm, the highest printing accuracy is 1mm. If the grating signal fractional frequency division method in this embodiment of the invention is applied, and 1mm is further subdivided into 10 equal parts, a printing accuracy of 0.1mm can be achieved. In other words, the printing processing method of the sand mold 3D printing equipment in this embodiment of the invention can improve the printing accuracy of sand casting products. The higher the accuracy, the stronger the adaptability to sand casting products of different scenarios and sizes, and the fewer times the scaling factor needs to be adjusted, which further improves printing efficiency.

[0094] Step 140: Determine the actual sand casting size of the sand casting product after printing, and determine the scaling factor based on the actual sand casting size and the designed sand casting size;

[0095] For example, the ratio of the actual sand casting size to the designed sand casting size is determined as the scaling factor.

[0096] Step 150: Process the CLI format slice file based on the scaling factor to obtain the target PRT format image file, and then print the target PRT format image file.

[0097] Step 150 may specifically include:

[0098] Parsing steps: Parse all vector elements in the CLI format slice file;

[0099] The CLI format slice file stores vector data (vector elements can accurately describe the geometric features of the graphic, such as the coordinates of lines and contours, and are not easily distorted when scaled up or down). This step is to use a program or corresponding parsing tool to extract these vector elements from the CLI file, understand their structure and meaning, and prepare for subsequent transformations (such as scaling) of each layer of the graphic.

[0100] Element processing steps: Based on the scaling factor, process each vector element in all vector elements to obtain the target PRT format image file.

[0101] The element processing steps may include: 1) multiplying the dot matrix coordinates obtained by splitting each vector element by the scaling factor to obtain the scaled dot matrix value; 2) filling the scaled dot matrix value onto the prt image to obtain the target PRT format image file.

[0102] Next, the element processing steps will be illustrated with an example. The CLI format slice file stores a rectangle, and its outline is described by the coordinates of its four vertices. The vector data is [(1,1), (5,1), (5,4), (1,4)] (these four coordinate points represent the four corners of the rectangle). The scaling factor is 3 in both the x and y directions (that is, the rectangle will be enlarged by a factor of 3 in both the x and y directions). For step 1), firstly, the raster is split. The vector element (rectangle) is to be converted into a raster by filling and describing the outline and interior of the rectangle with multiple coordinate points (similar to breaking down the lines and surfaces of a rectangle into many small "pixel" coordinates). To simplify the description, this embodiment only splits the rectangle into its four vertices and three midpoints of its edges. The resulting point coordinates are as follows: [(1,1), (2,1), (3,1), (4,1), (5,1), (5,2), (5,3), (5,4), (1,2), (1,3), (1,4)]. Next, the x and y values ​​of each point coordinate are multiplied by a scaling factor of 3 to obtain the scaled point values: [(3,3), (6,3), (9,3), (12,3), (15,3), (15,6), (15,9), (15,12), (3,6), (3,9), (3,12)]. For step 2), firstly, the bitmap values ​​are filled into the PRT image. For each scaled bitmap coordinate, the PRT image will record these points at the corresponding (x,y) position. After all the scaled bitmap values ​​have been filled into the corresponding positions in the PRT image, the PRT image will encapsulate these bitmap data into a target PRT format image file according to its own format rules (such as how to store the coordinates of these points, how to associate the image resolution, color and other attributes).

[0103] To illustrate the filling problem, filling involves assigning printable attributes to the scaled dot matrix, such as filling a rectangle with blue (RGB:0,0,255). Assigning color attributes (fill color values) to the scaled dot matrix means adding color data (RGB values) to each scaled dot coordinate, forming composite data of coordinates and color: [(3,3,0,0,255),(6,3,0,0,255),(9,3,0,0,255),(12,3,0,0,255),(15,3,0,0,255),(15,6,0,0,255),(15,9,0,0,255),(15,12,0,0,255),(3,6,0,0,255),(3,9,0,0,255),(3,12,0,0,255)]. The PRT image rules are set as follows: resolution 100×100 pixels, coordinates corresponding to pixel positions (x corresponds to column, y corresponds to row). Based on these rules, colored dots are "drawn" one by one: for (3, 3, 0, 0, 255), the color is set to blue (RGB: 0, 0, 255) at the 3rd column and 3rd row pixel position of the PRT image. This process continues, embedding all colored dots into their corresponding pixel positions in the PRT image. Once all dots are drawn, the PRT image will display an enlarged rectangle composed of discrete blue dots.

[0104] In one embodiment, a 3D model of the sand-cast product to be printed is generated in CLI format according to user requirements, and then sliced. Upon receiving a scaling instruction from the user, the CLI format slices or PRT format images are multiplied by a scaling factor to scale them. It should be noted that the sand-laying height also needs to be scaled accordingly; that is, the sand-laying height data under each slice is also multiplied by a scaling factor. Then, sand-laying and inkjet printing are performed sequentially based on the slice data or PRT image data and the sand-laying height data. Specifically, this can be as follows: acquire slice data or PRT image data, control the printer nozzle to spray ink containing binder based on the slice data or PRT image data, then the printing platform descends to the height corresponding to that layer, the first scraper pushes the sand on the sand table onto the printing platform, and the second scraper smooths the sand on the printing platform. Acquire the next slice data or PRT image data, and control the printer nozzle to spray ink containing binder based on the next slice data or PRT image data, then the printing platform descends to the height corresponding to that layer, the first scraper pushes the sand on the sand table onto the printing platform, and the second scraper smooths the sand on the printing platform. Repeat the sand-laying and ink-jetting process layer by layer until the 3D inkjet printing is complete.

[0105] In one optional implementation, first confirm the format of the slice file. Then, use a programming language (such as Python) to read the file content. Parse the move and extrusion instructions according to the file format; these instructions typically contain the coordinate information of vector elements. Extract the coordinate value of each vector element from the parsed instructions. Multiply each coordinate value by a scaling factor to obtain the scaled coordinate values. Store the scaled coordinate values ​​in an appropriate data structure for subsequent processing. Determine how to color fill the scaled coordinate values ​​according to requirements. This may involve converting vector elements into polygons and filling them using a graphics library. Use a graphics library (such as Pillow, OpenCV, etc.) to generate an image according to the filling strategy. In this process, it may be necessary to convert vector data into pixel data. Determine parameters such as image resolution and color depth to ensure that the image quality meets requirements. Determine the specifications and requirements of the PRT format to ensure that the generated image file conforms to the standard of this format. Write code using a programming language to save the generated image as a PRT format file. After saving as a PRT format file, use appropriate software or tools to open and verify that the file is correct. Understandably, when selecting a graphics library, it is necessary to choose a suitable graphics library based on the requirements to ensure that images that meet the requirements can be generated.

[0106] In existing technologies, when the current sand casting size differs from the required sand casting size and needs to be modified, or when multiple sand castings of different sizes need to be printed, the original STL 3D model is often scaled. After scaling, it needs to be re-sliced, but scaling the original STL 3D model is time-consuming. However, in this embodiment of the invention, there is no need to scale the original STL 3D model. Instead, the vector elements of the sliced ​​CLI format file are directly parsed using a parsing method. Then, each vector element is processed based on the scaling factor to obtain the target PRT format image file. This eliminates the steps of regenerating the 3D model and slicing the 3D model, allowing for direct printing and improving the printing speed compared to existing technologies.

[0107] In an optional embodiment, either CLI slices or PRT format images can be scaled. Compared to existing technologies, this implementation method involves re-enlarging or reducing the 3D model when a user needs to enlarge or reduce the product to be printed, re-slicing the enlarged or reduced 3D model, converting the slices into a printer-recognizable PRT format, and transmitting them to the printer one by one, which is inefficient. In some scenarios, such as when multiple copies of the same product need to be printed, or when a user needs to print a decorative item to place in an exhibition hall, multiple products of different sizes are usually requested for on-site viewing and selection of the most suitable one. Another example is when a user needs to repeatedly adjust the size of a 3D product, such as printing flowerpots for multiple flowers of different sizes. Each flower has a different size, therefore the flowerpot size is also different. Typically, the size of the product to be printed is adjusted in real-time based on the measured flower size, i.e., the size of the product to be printed is repeatedly adjusted.

[0108] In these scenarios, the method of directly adjusting the size of CLI slices and PRT format images in this embodiment saves printing steps and improves printing efficiency. Industrial mass production scenarios are usually characterized by a large number of products to be printed and frequent adjustments; therefore, the solution in this embodiment greatly improves printing efficiency in industrial 3D mass production scenarios.

[0109] Understandably, the printing process of sand mold 3D printing equipment may also include:

[0110] When printing the current PRT format image sub-file, the next CLI format slice is converted to obtain the next PRT format image sub-file corresponding to the next CLI format slice.

[0111] As can be seen from the above, converting the format while printing can improve printing efficiency.

[0112] In an optional embodiment, to further optimize printing efficiency in scenarios with high printing efficiency requirements, such as large-scale 3D printing scenarios or continuous 3D printing scenarios, in the step of converting CLI format slice files into corresponding PRT format image files, the printer can be directly controlled to start printing the first PRT format image file when converting the first CLI format slice file into a PRT format image file. During the printing of the first PRT format image file, the subsequent CLI format slice files are converted into PRT format image files. After the printing task of the first PRT format image file is completed, the memory of the first PRT format image file is released. The above operation of converting the next slice from CLI format file to PRT format image file is repeated when printing the current PRT format image file. When the printing task of the current PRT format image file is completed, the memory of the current PRT format image file is released until all printing tasks are completed or a stop printing command is received.

[0113] This embodiment controls the printer head to begin printing after the first CLI format slice file has been converted to a PRT format image file, and before all CLI format slice files have been converted to PRT format image files. While the first CLI format slice file is being converted to a PRT format image file, the printer is directly controlled to print the first PRT format image file, shortening the preprocessing time and improving 3D printing efficiency. Simultaneously, the conversion of unfinished CLI format slice files to PRT format image files is completed, shortening the overall printing process time and improving 3D printing efficiency. After the printing of the current PRT format image file is completed, the memory for that PRT format image file is released, saving storage memory. When a print stop command is received, only a portion of the CLI format slice file conversion to PRT format image files is completed, reducing the workload on the PC and saving operating memory.

[0114] Combination Figure 3 This section explains the overall process of sand mold 3D printing equipment:

[0115] Step 310: Obtain the 3D model of the sand-cast product to be printed; the 3D model is an STL file;

[0116] Step 320: Slice the STL file;

[0117] Step 330: Generate CLI format slice files and convert them to PRT format image files;

[0118] Step 340: Perform 3D printing using a preset fractional frequency division method for the grating signal;

[0119] Step 350: Determine the actual sand casting dimensions of the printed product;

[0120] Step 360: Compare the actual sand casting dimensions with the designed sand casting dimensions;

[0121] Step 370: Determine if scaling is needed. If scaling is needed, proceed to step 371; otherwise, proceed to step 380.

[0122] Step 371: Parse all vector elements in the CLI format slice file;

[0123] Step 372: Multiply the coordinate value of each vector element by the scaling factor in the xy direction;

[0124] Step 373: Fill the image corresponding to the scaled coordinate values ​​with a single color and draw it to a PRT format image file;

[0125] Step 374: Generate the target PRT format image file;

[0126] Step 375: 3D print the target PRT format image file, proceed to step 380;

[0127] Step 380: Printing complete.

[0128] To improve 3D printing efficiency, this embodiment first modifies the existing 3D inkjet printing process using a first approach. The existing technology, which requires regenerating a new model and slicing it to scale the 3D printed product, eliminates the need for model regeneration and slicing. Instead, the original slices and sand thickness parameters are directly multiplied by a scaling factor, significantly improving printing efficiency, particularly in mass production and large-scale 3D printing scenarios. Building upon this improved process, this embodiment also provides a second approach, introducing grating frequency division technology to avoid multi-pass printing. By modifying the nozzle ignition control method on the printing board, printing efficiency is further improved while maintaining printing resolution, resulting in even better printing efficiency in mass production and large-scale 3D printing scenarios. In actual production, personnel can flexibly choose to use the first approach or a combination of both approaches based on the specific printing scenario and desired printing effect.

[0129] The printing processing apparatus of the sand mold 3D printing equipment provided by the present invention is described below. The printing processing apparatus of the sand mold 3D printing equipment described below can be referred to in correspondence with the printing processing method of the sand mold 3D printing equipment described above.

[0130] like Figure 4As shown, this embodiment of the invention also provides a printing processing apparatus for a sand mold 3D printing device, used to implement the printing processing method of the sand mold 3D printing device in any of the above embodiments. The printing processing apparatus for the sand mold 3D printing device may include:

[0131] The acquisition module 410 is used to acquire sand casting product information of the sand casting product to be printed; the sand casting product information includes at least the STL format 3D model corresponding to the sand casting product to be printed and the designed sand casting dimensions.

[0132] The slicing module 420 is used to slice the STL format 3D model to obtain a CLI format slice file; the CLI format slice file includes N layers of CLI format slices; where N is a positive integer greater than 2;

[0133] The first processing module 430 is used to convert the CLI format slice file into the corresponding PRT format image file, and when sand is laid by the sand spreader in the sand mold 3D printing equipment, it processes the PRT format image file for printing based on the preset grating signal fractional frequency division method to complete the printing.

[0134] The module 440 is used to determine the actual sand casting size of the sand casting product after printing, and to determine the scaling factor based on the actual sand casting size and the designed sand casting size;

[0135] The second processing module 450 is used to process the CLI format slice file based on the scaling factor to obtain the target PRT format image file, and to print the target PRT format image file.

[0136] Compared with existing technologies, the present invention provides a printing processing method for sand mold 3D printing equipment. After slicing the STL format 3D model, the CLI format slice file is converted into the corresponding PRT format image file. In this way, when there is a difference between the actual sand casting size of the printed product and the designed sand casting size, the CLI format slice file can be directly adjusted by scaling factor, without having to readjust the original 3D model and then slice it again as in traditional technology. This greatly improves printing efficiency. In addition, a preset raster signal fractional frequency division method is used in the printing process, which improves printing accuracy and reduces the number of repeated printing adjustments, further improving printing efficiency.

[0137] In one alternative implementation, the second processing module 450 is specifically used for:

[0138] Parse all vector elements in a CLI format slice file;

[0139] Based on the scaling factor, each vector element in all vector elements is processed to obtain the target PRT format image file.

[0140] In one alternative implementation, the second processing module 450 is specifically used for:

[0141] Multiply the matrix coordinates of each vector element by the scaling factor to obtain the scaled matrix values;

[0142] The scaled bitmap values ​​are filled and drawn onto the RPT format image to obtain the target PRT format image file.

[0143] The PRT format image file includes N PRT format image sub-files corresponding to N layers of CLI format slices; the first processing module 430 is specifically used for:

[0144] Determine the frequency division ratio based on printing requirements;

[0145] When sand is laid using a sand spreader, the printing carriage in the sand mold 3D printing equipment sprays binder onto the sand casting product to be printed based on the frequency division ratio, thus completing the printing of each PRT format image sub-file.

[0146] The first processing module 430 is specifically used for:

[0147] Determine the initial resolution and target resolution of the sand casting product to be printed;

[0148] The frequency division ratio is determined based on the initial resolution and the target resolution.

[0149] The first processing module 430 is specifically used for:

[0150] Calculate the greatest common divisor of the initial resolution and the target resolution;

[0151] Substituting the greatest common divisor and the target resolution into the formula:

[0152] ;

[0153] The frequency division ratio is calculated; where, It is the frequency division ratio. For the target resolution, It is the greatest common divisor.

[0154] The printing processing unit of the sand mold 3D printing equipment is also used to: convert the format of the next CLI format slice when printing the current PRT format image sub-file, so as to obtain the next PRT format image sub-file corresponding to the next CLI format slice.

[0155] like Figure 5As shown, this embodiment of the invention also provides an electronic device, which may include: a processor 510, a communication interface 520, a memory 530, and a communication bus, wherein the processor 510, the communication interface 520, and the memory 530 communicate with each other through the communication bus. The memory 530 stores a computer program that can be executed by the processor 510; when the processor 510 executes the computer program, it can perform the printing process method of the sand mold 3D printing device in any of the above embodiments.

[0156] Furthermore, the logical instructions in the aforementioned memory 530 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.

[0157] In another aspect, the present invention also provides a non-transitory computer-readable storage medium, wherein the computer storage medium stores instructions that, when executed, implement the printing process method of the sand mold 3D printing device in any of the above embodiments.

[0158] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer programs or instructions. When a computer program or instruction is loaded and executed on a computer, the processes or functions of the embodiments of this application are performed, in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a terminal, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, a computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video disc (DVD); or it can be a semiconductor medium, such as a solid-state drive (SSD).

[0159] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, the disclosure, and the appended claims in carrying out the claimed invention. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0160] Although the invention has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made therein without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely exemplary descriptions of the invention as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if such modifications and modifications of the invention fall within the scope of the claims and their equivalents, the invention is also intended to include such modifications and modifications.

Claims

1. A printing process for a sand mold 3D printing device, characterized in that, include: Obtain sand casting product information for the sand casting product to be printed; the sand casting product information includes at least an STL format 3D model corresponding to the sand casting product to be printed and the designed sand casting dimensions; The STL format 3D model is sliced ​​to obtain a CLI format slice file; the CLI format slice file includes N layers of CLI format slices; where N is a positive integer greater than 2; The CLI format slice file is converted into a corresponding PRT format image file. When sand is spread using the sand spreader in the sand mold 3D printing equipment, the PRT format image file is printed based on a preset grating signal fractional frequency division method to complete the printing. The PRT format image file includes N PRT format image sub-files corresponding to the N layers of CLI format slices. Determine the actual sand casting size of the sand casting product after printing, and determine the scaling factor based on the actual sand casting size and the designed sand casting size; The CLI format slice file is processed based on the scaling factor to obtain the target PRT format image file, and the target PRT format image file is then printed. The process of processing the CLI format slice file based on the scaling factor to obtain the target PRT format image file includes: Parse all vector elements in the CLI format slice file; Multiply the dot matrix coordinates obtained by splitting each vector element by the scaling factor to obtain the scaled dot matrix value; The scaled bit values ​​are filled and drawn onto an RPT format image to obtain the target PRT format image file.

2. The printing process of the sand mold 3D printing equipment according to claim 1, characterized in that, The printing process of the PRT format image file based on the preset fractional frequency division method of the grating signal and the sand spreader in the sand mold 3D printing equipment includes: Determine the frequency division ratio based on printing requirements; When sand is spread using the sand spreader, the printing carriage in the sand mold 3D printing equipment is controlled based on the frequency division ratio to spray the binder onto the sand casting product to be printed, thereby completing the printing of each PRT format image sub-file.

3. The printing process of the sand mold 3D printing equipment according to claim 2, characterized in that, Determining the frequency division ratio based on printing requirements includes: Determine the initial resolution and target resolution of the sand casting product to be printed; The frequency division ratio is determined based on the initial resolution and the target resolution.

4. The printing process of the sand mold 3D printing equipment according to claim 3, characterized in that, Determining the frequency division ratio based on the initial resolution and the target resolution includes: Calculate the greatest common divisor of the initial resolution and the target resolution; Substituting the greatest common divisor and the target resolution into the formula: The frequency division ratio is calculated; where, The frequency division ratio is... The target resolution. The greatest common divisor is denoted as .

5. The printing process of the sand mold 3D printing equipment according to claim 2, characterized in that, Also includes: When printing the current PRT format image sub-file, the next CLI format slice is converted to obtain the next PRT format image sub-file corresponding to the next CLI format slice.

6. A printing processing device for a sand mold 3D printing equipment, characterized in that, include: The acquisition module is used to acquire sand casting product information of the sand casting product to be printed; the sand casting product information includes at least the STL format three-dimensional model corresponding to the sand casting product to be printed and the designed sand casting dimensions. The slicing module is used to slice the STL format 3D model to obtain a CLI format slice file; the CLI format slice file includes N layers of CLI format slices; where N is a positive integer greater than 2; The first processing module is used to convert the CLI format slice file into the corresponding PRT format image file, and when sand is laid using the sand spreader in the sand mold 3D printing equipment, the PRT format image file is printed based on a preset grating signal fractional frequency division method to complete the printing. The determination module is used to determine the actual sand casting size of the sand casting product after printing, and to determine the scaling factor based on the actual sand casting size and the designed sand casting size; The second processing module is used to process the CLI format slice file based on the scaling factor to obtain the target PRT format image file, and to print the target PRT format image file. The first processing module is specifically used for: Parse all vector elements in the CLI format slice file; Multiply the dot matrix coordinates obtained by splitting each vector element by the scaling factor to obtain the scaled dot matrix value; The scaled bit values ​​are filled and drawn onto an RPT format image to obtain the target PRT format image file.

7. An electronic device, characterized in that, include: The processor, the communication interface, the memory, and the communication bus; wherein the processor, the communication interface, and the memory communicate via the communication bus. The memory stores a computer program that can be run by the processor; when the processor runs the computer program, it executes the printing process method of the sand mold 3D printing equipment as described in any one of claims 1-5.

8. A computer storage medium, characterized in that, The computer storage medium stores instructions that, when executed, implement the printing process method of the sand mold 3D printing equipment according to any one of claims 1-5.

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