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

Abstract

The invention discloses a printing treatment method and device of sand mold 3D printing equipment and related equipment, relates to the technical field of sand mold 3D printing, and aims to solve the problem of low sand mold 3D printing efficiency in the prior art. The method comprises the steps that sand casting product information of a sand casting product to be printed is obtained; slicing the STL format three-dimensional model to obtain a cli format slice file; the cli-format slice file is converted into a corresponding PRT-format image file, and when a sand paver in the sand mold 3D printing equipment is adopted to pave sand, printing processing is conducted on the PRT-format image file based on a preset grating signal fractional frequency division method, and printing is completed; the actual sand casting size of the sand casting product after printing is completed is determined, and a scaling coefficient is determined based on the actual sand casting size and the designed sand casting size; and processing the cli-format slice file based on the zoom coefficient to obtain a target PRT-format image file, and printing the target PRT-format image file. Therefore, the printing efficiency can be improved.

Description

Technical Field

[0001] The present invention relates to the field of sand mold 3D printing technology, and in particular to a printing processing method, device and related equipment of a sand mold 3D printing device. Background Art

[0002] To improve printing efficiency, the foundry industry is now widely using sand mold 3D inkjet printing equipment. 3D inkjet printing technology, which combines inkjet and 3D printing, can precisely and efficiently produce complex structures in three dimensions. Its unique operating principle and wide applicability have given inkjet 3D printing technology enormous potential, making it a key driver of new material innovation.

[0003] In existing technology, using sand mold 3D printing equipment for printing often requires first generating a fixed-format 3D model of the sand casting product to be printed, based on user requirements. This model is then sliced. After slicing, sanding and inkjetting are performed sequentially according to the slice specifications. This sanding and inkjetting process is repeated layer by layer until the 3D inkjet print is complete. Adjusting the dimensions of the printed 3D product typically requires regenerating the 3D model and slicing it again, making the printing process cumbersome and inefficient.

[0004] It can be seen that how to improve the efficiency of 3D inkjet printing is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The purpose of the present invention is to provide a printing processing method, device and related equipment for sand mold 3D printing equipment to improve the printing efficiency of sand mold 3D printing equipment.

[0006] In order to achieve the above object, the present invention provides the following technical solutions: In a first aspect, the present invention provides a printing processing method of a sand mold 3D printing device, comprising: Acquire sand casting product information of the sand casting product to be printed; the sand casting product information at least includes an STL format three-dimensional model corresponding to the sand casting product to be printed and a designed sand casting size; Slicing the STL format three-dimensional model to obtain a CLI format slice file; the CLI format slice file includes N layers of CLI format slices; wherein N is a positive integer greater than 2; Converting the CLI format slice file into a corresponding PRT format image file, and performing printing processing on the PRT format image file based on a preset grating signal fractional frequency division method when performing sand spreading using a sand spreading device in the sand mold 3D printing device, thereby completing printing; determining an actual sand casting size of the sand casting product after printing is completed, and determining a 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 a target PRT format image file, and the target PRT format image file is printed.

[0007] Optionally, the processing of the CLI format slice file based on the scaling factor to obtain a target PRT format image file includes: Parse all vector elements in the CLI format slice file; Based on the scaling factor, each vector element in all vector elements is processed to obtain the target PRT format image file.

[0008] Optionally, the processing of each vector element in all vector elements based on the scaling factor to obtain the target PRT format image file includes: Multiplying the lattice coordinate value obtained by splitting each vector element by the scaling factor to obtain a scaled lattice value; The scaled dot matrix values are filled and drawn into the RPT format image to obtain the target PRT format image file.

[0009] Optionally, the PRT format image file includes N PRT format image sub-files corresponding to the N layers of CLI format slices; The printing process of the PRT format image file based on the preset grating signal fractional frequency division method and the sand spreading device in the sand mold 3D printing device includes: Determine the frequency division ratio according to printing requirements; When the sand spreader is used for spreading sand, the printing carriage in the sand mold 3D printing device is controlled based on the frequency division ratio to spray the binder on the sand casting product to be printed, thereby completing the printing of each PRT format image sub-file.

[0010] Optionally, determining the frequency division ratio according to printing requirements includes: Determining an initial resolution and a 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.

[0011] Optionally, determining the frequency division ratio based on the initial resolution and the target resolution includes: Calculating 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 obtained by calculation; wherein, is the frequency division ratio, is the target resolution, is the greatest common divisor.

[0012] Optionally, the printing processing method of the sand mold 3D printing device further includes: When the current PRT format image sub-file is printed, the format of the next CLI format slice is converted to obtain the next PRT format image sub-file corresponding to the next CLI format slice.

[0013] Compared with the prior art, the present invention provides a printing processing method for a sand mold 3D printing device. After slicing the STL format three-dimensional model, the CLI format slice file is converted into a corresponding PRT format image file. In this way, when the actual sand casting size of the printed product differs from the designed sand casting size, the CLI format slice file can be directly adjusted by the scaling factor, without having to readjust the original three-dimensional model and then slice it as in traditional technology. This greatly improves printing efficiency. In addition, a preset grating signal fractional frequency division method is also used in the printing process, which improves printing accuracy, reduces the number of repeated printing adjustments, and further improves printing efficiency.

[0014] In a second aspect, the present invention provides a printing processing device for a sand mold 3D printing device, comprising: An acquisition module is used to acquire sand casting product information of the sand casting product to be printed; the sand casting product information at least includes an STL format three-dimensional model corresponding to the sand casting product to be printed and a designed sand casting size; a slicing module, configured to slice the STL format three-dimensional model to obtain a CLI format slice file; the CLI format slice file includes N layers of CLI format slices; wherein N is a positive integer greater than 2; A first processing module is configured to convert the CLI format slice file into a corresponding PRT format image file, and to print the PRT format image file based on a preset grating signal fractional frequency division method when using a sander in the sand mold 3D printing device to complete printing; a determination module, configured to determine an actual sand casting size of the sand casting product after printing is completed, and determine a 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 a target PRT format image file, and print the target PRT format image file.

[0015] In a third aspect, 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 that can be run by the processor; when the processor runs the computer program, it executes the printing processing method of the sand mold 3D printing device described in any one of the above items.

[0016] In a fourth aspect, the present invention provides a computer storage medium having instructions stored therein. When the instructions are executed, the printing processing method of the sand mold 3D printing device described in any one of the above items is implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 One of the flow charts of a printing process method of a sand mold 3D printing device provided in one embodiment of the present invention; Figure 2 A schematic diagram of a frequency division process provided by one embodiment of the present invention; Figure 3 A second flow chart of a printing method for a sand mold 3D printing device according to an embodiment of the present invention; Figure 4 A schematic structural diagram of a printing processing device of a sand mold 3D printing device provided in one embodiment of the present invention; Figure 5 A schematic structural diagram of an electronic device provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0018] To facilitate a clear description of the technical solutions of the embodiments of the present invention, the words "first" and "second" are used in the embodiments of the present invention to distinguish between identical or similar items with substantially the same functions and effects. For example, the first threshold and the second threshold are merely used to distinguish between different thresholds and do not limit their order. Those skilled in the art will understand that the words "first" and "second" do not limit the quantity or execution order, and the words "first" and "second" do not necessarily mean different.

[0019] It should be noted that, in the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present invention should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0020] In the present invention, "at least one" means one or more, "more than one" means two or more, and "and / or" describes the association relationship between associated objects, indicating that three types of relationships can exist.

[0021] In the prior art, when performing 3D inkjet printing, it is usually necessary to first generate a fixed-format three-dimensional model of the sand casting product to be printed according to user needs, and then slice it. After slicing is completed, sand laying and inkjetting are carried out in sequence according to the specification data of the slices. The sand laying and inkjet process is repeated layer by layer until the 3D inkjet printing is completed. When the size of the printed 3D product needs to be adjusted, the three-dimensional model is usually regenerated and sliced. The printing process is cumbersome and inefficient. To solve the above problems, see Figure 1 , an embodiment of the present invention provides a printing processing method of a sand mold 3D printing device, which may include: Step 110: Acquire sand casting product information of the sand casting product to be printed; the sand casting product information at least includes an STL format three-dimensional model corresponding to the sand casting product to be printed and designed sand casting dimensions; In one embodiment, a model file transmitted by a user can be received. The user can be a customer requiring 3D inkjet printing or an engineer conducting testing. The model file to be printed is exported to STL format using commonly used CAD software, such as SolidWorks, Creo, and ZBrush. Alternatively, modeling software such as Blender and MeshMixer can be used to directly generate STL files. After generating the original model of the product to be printed, it is exported to an STL file. The topology of the STL model file can be checked by relevant personnel, or by a built-in function within the software. If any topological issues are found, the STL model file is regenerated, and the checking and correction process is repeated until the topological issues are resolved. If no topological issues are found, sand casting product information is generated based on the STL model file, and the STL model file, i.e., the STL 3D model corresponding to the sand casting product to be printed, is input into slicing software for slicing. This topological structure check of the STL model file in this embodiment can improve the success rate of converting the digital model to a physical sand mold, thereby improving printing efficiency.

[0022] Sand mold 3D printing equipment is a core equipment that uses 3D printing technology to manufacture sand casting molds or sand molds. It can quickly and accurately produce sand molds of complex shapes and simplify the casting process.

[0023] The sand mold 3D printing device in the embodiment of the present invention includes at least a sand paving device, a printing carriage, a grating signal generator, etc. Among them, the printing carriage adopts binder jetting technology.

[0024] The STL (Stereo Lithograph) format is a widely used 3D model file format for representing the surface geometry of 3D solid models. It discretizes the model surface into a series of small triangular facets, 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 outward. Together, these facets define the surface of the 3D model.

[0025] The STL format only contains geometric information and does not involve advanced properties such as color and material, so the file format is relatively simple.

[0026] STL files come in two main formats: ASCII and binary. ASCII stores triangular facet information in text format, making it easier to read and edit. However, the file size is relatively large, making it unsuitable for large-scale data transmission. Binary stores triangular facet information in binary format, resulting in smaller file sizes and faster read speeds, making it more suitable for data transmission and storage in practical applications.

[0027] 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; cli (Common Layer Interface) is a slice file format.

[0028] The CLI format slice file contains the printing instructions after the STL format 3D model is sliced, such as layer height, fill density, printing speed and other parameters. It is used to guide the sand mold 3D printing equipment to build the sand casting product layer by layer according to N layers of CLI format slices.

[0029] Step 120 may specifically include the following steps: Step 1: Choose the right slicing software. Slicing software is a tool specifically designed to convert 3D models into slice files that can be read by 3D printers. Common slicing software includes Cura, Slic3r, and Simplify3D. These programs generally support the STL format as input and can output slice files in a variety of formats, including CLI (which may be called by other specific names in some software, but is essentially similar).

[0030] Step 2: In the slicing software, you first need to import the 3D model in STL format. This is usually done through the software's "Open" or "Import" function. Once imported, the model will be displayed in the software's 3D view, where users can rotate, scale, and move the model for a better view.

[0031] Step 3: Next, you need to set the slicing parameters. These parameters include layer thickness, print speed, infill ratio, and support structure, which directly affect the quality and effect of 3D printing. Choose appropriate parameters based on your actual needs, such as printer performance, material properties, and printing requirements.

[0032] Step 4: After setting the parameters, proceed to 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 the printing information of each layer.

[0033] Step 5: Once slicing is complete, choose to export the slice file to CLI format (or another similar format supported by the software). When exporting, select the save path and file name, and ensure the file format is correct. Once the export is successful, you can transfer the CLI format slice file to your 3D printer for printing.

[0034] In an optional embodiment, the STL model file is input into format conversion software. Conversion software such as Autodesk Netfabb, Materialise Magics, and 3DSystems 3DPrint outputs CLI format files in versions cli2.0, cli1.0, and cli1.2, respectively. Version cli1.0 is preferred because it is compatible with most commercially available industrial equipment. After the STL model file is input into the format conversion software, the model can be repaired using the software's built-in automatic repair function, or personnel can manually repair problems based on experience. After the repair is complete, the slicing parameters entered by front-end personnel or from the sand casting product information are received. These slicing parameters include slice thickness, slice profile accuracy, adhesive parameters, interlayer curing time, number of edge reinforcement injections, and designed sand casting dimensions. After obtaining the CLI-formatted slice file, a trial print can be performed using a printer. Once the print results match the user's requirements, batch printing can be performed, thereby improving printing efficiency.

[0035] Step 130: Convert the CLI format slice file into a corresponding PRT format image file, and when using a sander in a sand mold 3D printing device to perform sand spreading, print the PRT format image file based on a preset grating signal fractional frequency division method to complete printing; In one embodiment, because the printer can only read PRT images, the CLI slice file needs to be converted into a corresponding PRT image file before being input into the 3D printer for printing. If the relevant personnel have RIP software capable of CLI-to-PRT conversion, the existing RIP software's built-in function can be used to convert the CLI slice file into the corresponding PRT image file. Alternatively, the relevant personnel can convert the CLI file layer by layer to obtain the PRT image.

[0036] This embodiment provides a method for relevant personnel to convert a CLI format slice file into a PRT format image file. The specific implementation method 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 to obtain information such as the actual pixel unit, model size, creation time, and slice thickness in the file header. The actual pixel unit is the actual length between the coordinates of adjacent pixel points. Next, the geometry section of the CLI file is read. Each layer of the image contains multiple polygonal outlines. Each polygonal outline is obtained by the number and coordinates of the points contained in the geometry section. For example, if the geometry section contains 4; 0, 0; 50, 0; 50, 50; 0, 50; 3; 20, 10; 30, 20; 30, 10, it can be seen that there are two polygonal outlines in the image of this layer, with 4 and 3 vertices respectively. That is, the polygons are a quadrilateral and a triangle respectively. The four vertex coordinates of the quadrilateral are (0, 0), (50, 0), (50, 50), and (0, 50), and the three vertex coordinates of the triangle are (20, 10), (30, 20), and (30, 10). The geometry section may also contain a straight line formed by two vertices. Furthermore, the color section of the CLI file is read. The color section contains the pixel coordinate values and the color information corresponding to the coordinate values. This color information is usually stored in RGB format.

[0037] After parsing the CLI file, the user's desired print product resolution and color depth are obtained. A binary image corresponding to the required resolution and color depth is generated based on the resolution and color depth. The initial values in the binary image are all 0. Based on the actual pixel units in the CLI header file, the coordinate information of the polygon outline in the geometry section, and the pixel value coordinates in the color section, the positions to be filled in the binary image are obtained, and a mapping relationship between the coordinates in the coordinate file for the positions to be filled is established. The preset RGB-YMCK conversion template is retrieved, and binary filling is performed on the positions to be filled based on the conversion template, the mapping relationship, and the color information corresponding to the pixel coordinate values in the color section. This results in a PRT-formatted image file.

[0038] It is understandable that after the cli format slice file is converted into the corresponding PRT format image file, the PRT format image file includes N PRT format image sub-files corresponding to the N layers of cli format slices. Then step 130 may specifically include: Step 1: Determine the frequency division ratio based on printing requirements. Printing requirements generally involve the resolution of the sand casting product to be printed. The original sand casting product to be printed received by the product manufacturer has its own initial resolution, and the actual product is often printed with a target resolution. The second step: When using the sand spreader to spread sand, the printing carriage in the sand mold 3D printing equipment is controlled based on the frequency division ratio to spray the binder on the sand casting product to be printed, and the printing of each PRT format image sub-file is completed.

[0039] The first step may specifically include: Step 1: Determine the initial resolution and target resolution of the sand casting product to be printed; Step 2: Based on the initial and target resolutions, determine the division ratio.

[0040] In step 1, first, you need to understand the initial resolution of the sand casting product to be printed. This is usually provided by the product designer or manufacturer and reflects the level of detail of the product's original data.

[0041] Secondly, based on the printing requirements, the target resolution to be achieved when printing the actual product should be determined. The target resolution should take into account the product's end use, dimensional accuracy requirements, and the performance limitations of the printing equipment.

[0042] It is understandable that the initial resolution can also be determined by the properties of the printer itself. In this embodiment, the printer is usually equipped with a grating ruler on the movement path of the nozzle to assist in controlling the movement and ignition frequency of the nozzle. During the movement of the nozzle, the reader on the nozzle reads the position on the grating ruler in real time and feeds the position information back to the host computer. The host computer controls the nozzle to spray ink according to the position coordinates of the nozzle. The time interval for the nozzle to spray ink is usually determined by the grating interval when the printer leaves the factory, and the grating interval of the printer determines the ignition frequency of the nozzle. When the printer leaves the factory, a fixed grating interval is usually stored on the board in the host computer, that is, a fixed nozzle ignition frequency is stored in the board. It can be seen that the ignition interval of the printer determines the movement speed of the nozzle. In this embodiment, the grating interval stored in the board is updated, and the grating is further divided. At this time, the movement speed can be kept unchanged, and the ignition frequency can be increased to improve the resolution.

[0043] Therefore, in order to further improve the printing efficiency of the 3D printer, this embodiment provides a method for frequency division of the printer print control. For example, before, when the nozzle moves parallel to the grating within a unit length, there are two feedbacks sent to the board after the motion signal read by the grating reader. Each feedback of the motion signal will trigger the nozzle's spraying action once, that is, the nozzle movement of a unit length contains two spray control signals; after the grating control method is divided into three sections, the grating length corresponding to the feedback between two adjacent motion signals is divided into one third of the previous one. At this time, when the nozzle moves parallel to the grating within a unit length, there are six feedbacks sent to the board after the motion signal read by the grating reader, that is, the nozzle movement of a unit length contains six spray control signals. It can be seen that after the printer is divided into three sections, the inkjet is changed from two times to six times within the same unit length. At this time, if the movement speed is not changed, the inkjet frequency can be accelerated, thereby improving the printing resolution of the 3D printer.

[0044] In existing technologies, increasing print resolution typically requires increasing the number of print passes. This number refers to the number of times the print carriage, equipped with the nozzle, prints back and forth without stepping, i.e., during the scanning process. A scan path is the path along which the print carriage prints a complete row or column at a time. A step path is a path perpendicular to the scan path. The print carriage prints back and forth along the scan path according to a preset pass. After completing the scan path, the print carriage steps onto the adjacent scan path and continues printing back and forth according to the preset pass.

[0045] Different printing products require different PASS printing methods. Each additional PASS in the scanning process after each step doubles the time. The more PASSes there are, the lower the printing efficiency. The method for frequency-dividing the grating signal provided in this embodiment avoids the need for a large number of PASSes for printing, ensuring different resolutions while improving 3D printing efficiency.

[0046] In step 2, the division ratio refers to the ratio by which the printing device divides the raster signal when processing the image file. To achieve clear and accurate printing, the division ratio must be calculated based on the initial and target resolutions. 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, other methods (such as interpolation) may be necessary to increase the resolution.

[0047] It is understandable that after determining the frequency division ratio, some printing parameters may also be adjusted, such as the sanding speed, the raster scanning frequency, etc., to ensure that the printing process can accurately print according to the set resolution.

[0048] Step 2 may specifically include: Calculate the greatest common divisor of the initial resolution and the target resolution; Substitute the greatest common divisor and the target resolution into the formula: (1) The frequency division ratio is calculated; where, is the frequency division ratio, is the target resolution, is the greatest common divisor.

[0049] For example, if the initial resolution is 1000 and the target resolution is 2000, the greatest common divisor of the two is 1000. Then, substituting the target resolution 2000 and the greatest common divisor 1000 into formula (1), we get the frequency division ratio = 2000 / 1000 = 2. Figure 2 As shown, if the frequency division ratio is 2, that is, two signals are inserted into the original grating scale interval, the frequency of the output signal fout becomes twice the frequency of the input signal fin.

[0050] The above-described method can be used to frequency-divide the original grating scale signal (the grating signal initially set by the sand mold 3D printing device). For example, if the original grating scale signal spacing is 1mm, the maximum printing accuracy is 1mm. If the grating signal fractional frequency division method described in the embodiments of the present invention is applied, 1mm is further divided into 10 equal parts, and printing with an accuracy of 0.1mm can be achieved. In other words, the printing processing method of the sand mold 3D printing device described in the embodiments of the present invention can improve the printing accuracy of sand casting products. This improved accuracy improves the adaptability to different scenarios and sand casting products of different sizes, and the number of repeated adjustments using the scaling factor can be reduced, further improving printing efficiency.

[0051] Step 140: determining the actual sand casting size of the sand casting product after printing is completed, and determining a scaling factor based on the actual sand casting size and the designed sand casting size; For example, the ratio of the actual sand casting size to the designed sand casting size is determined as the scaling factor.

[0052] Step 150: Process the cli format slice file based on the scaling factor to obtain a target PRT format image file, and print the target PRT format image file.

[0053] Step 150 may specifically include: Parsing step: parse out all vector elements in the CLI format slice file; The CLI slice file stores vector data (vector elements can accurately describe the geometric features of graphics, such as the coordinates of lines and contours, and are not easily distorted when zoomed in or out). This step involves using 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 graphics. Element processing step: Based on the scaling factor, each vector element in all vector elements is processed to obtain a target PRT format image file.

[0054] Among them, the element processing step can include: 1) multiplying the dot coordinate value obtained by splitting each vector element by the scaling factor to obtain the scaled dot value; 2) filling and drawing the scaled dot value into the prt image to obtain the target PRT format image file.

[0055] Next, let's illustrate the element processing steps. A CLI-format slice file stores a rectangle, whose 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 in both the x and y directions is 3 (meaning that the rectangle will be magnified by 3 in both the x and y directions). For step 1), first, the lattice is split. To convert the vector element (rectangle) into a lattice, the outline and interior of the rectangle are filled with multiple coordinate points (similar to breaking down the lines and surface of a rectangle into many small "pixel" coordinates). To simplify the description, this embodiment only splits the four vertices and three edge midpoints of the rectangle. The resulting lattice 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)]. Secondly, the x and y values of each lattice coordinate are multiplied by a scaling factor of 3 to obtain the scaled lattice 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), first fill the dot matrix values into the PRT image. For each scaled dot matrix coordinate, the PRT image will record these points at the corresponding (x, y) position. When all the scaled dot matrix values are filled into the corresponding positions of the PRT image, the PRT image will encapsulate these dot matrix 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).

[0056] To illustrate the filling problem, filling is to assign printing attributes to the scaled dot matrix, for example, filling a rectangle with blue (RGB: 0, 0, 255). To assign color attributes (fill color values) to the scaled dot matrix, color data (RGB values) must be added to each scaled dot matrix coordinate, forming a composite data of coordinates + colors: [(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)]. Set the PRT image format to 100×100 pixel resolution and coordinates corresponding to pixel locations (x corresponds to column, y corresponds to row). Based on this PRT image format, "draw" colored dots one by one: for (3, 3, 0, 0, 255), set the color to blue (RGB: 0, 0, 255) at the pixel location in the third column and third row of the PRT image. Similarly, all colored dots will be embedded in the corresponding pixel locations of the PRT image. When all dots are drawn, the PRT image will appear as an enlarged rectangle composed of discrete blue dots.

[0057] In one embodiment, a 3D model of a sand casting product to be printed is generated in CLI format based on user requirements and then sliced. Upon receiving a scaling command from the user, the CLI slice or PRT image is multiplied by a scaling factor based on the scaling command to perform scaling. It should be noted that the sand layer height also needs to be scaled accordingly; that is, the sand layer height data for each slice is also multiplied by the scaling factor. Sand layering and inkjet printing are then performed sequentially based on the slice data or PRT image data and the sand layer height data. Specifically, the following steps may be performed: Slice data or PRT image data is acquired, and based on the slice data or PRT image data, the printer nozzle is controlled to spray ink containing a binder. The printing platform is then lowered to a height corresponding to the layer. A first scraper pushes the sand on the sand table onto the printing platform, and a second scraper smoothes the sand on the printing platform. Next slice data or PRT image data is acquired, and based on the next slice data or PRT image data, the printer nozzle is controlled to spray ink containing a binder. The printing platform is then lowered to a height corresponding to the layer. The first scraper pushes the sand on the sand table onto the printing platform, and a second scraper smoothes the sand on the printing platform. Repeat the above sanding and inkjet process layer by layer until the 3D inkjet printing is completed.

[0058] In one optional embodiment, the format of the slice file is first confirmed. The file contents are then read using a programming language (e.g., Python). Move and extrude instructions are parsed according to the file format. These instructions typically contain coordinate information for vector elements. The coordinate values of each vector element are extracted from the parsed instructions. Each coordinate value is multiplied by a scaling factor to obtain the scaled coordinate value. The scaled coordinate values are stored in an appropriate data structure for subsequent processing. Determine how to color-fill the scaled coordinate values based on requirements. This may involve converting the vector elements into polygons and filling them using a graphics library. Use a graphics library (e.g., Pillow, OpenCV, etc.) to generate an image based on the filling strategy. During this process, it may be necessary to convert the vector data into pixel data. Determine image parameters such as resolution and color depth to ensure that the image quality meets requirements. Determine the specifications and requirements for the PRT format to ensure that the generated image file complies with the standards of that format. Write code using a programming language and save the generated image as a PRT format file. After saving in PRT format, the file can be opened and verified to be correct using appropriate software or tools. It is understandable that when selecting a graphics library, you need to choose an appropriate graphics library according to your needs to ensure that you can generate images that meet your requirements.

[0059] In the prior art, when the current sand casting dimensions differ from the desired dimensions and need to be modified, or when printing multiple sand castings of different sizes, the original STL 3D model is often scaled. After scaling, the model must then be re-sliced. However, scaling the original STL 3D model is time-consuming. However, in the embodiments of the present invention, scaling the original STL 3D model is unnecessary. Instead, the vector elements in the sliced CLI format slice file are directly parsed through a parsing method. Each vector element is then processed based on the scaling factor to generate the target PRT format image file. This eliminates the steps of regenerating and slicing the 3D model and allows for direct printing, resulting in a higher printing speed than the prior art.

[0060] In an optional embodiment, either CLI slices or PRT format images can be scaled. Compared to the prior art, this embodiment is less efficient than the conventional method in which, when a user needs to enlarge or reduce a 3D-printed product, the user first re-enlarges or reduces the 3D model, re-slices the enlarged or reduced 3D model, and then converts the slices into a PRT format recognizable by the printer and transmits them one by one to the printer. In certain scenarios, such as when multiple copies of the same product need to be printed, or when a user needs to print an ornament to be placed in an exhibition hall, multiple copies of different sizes are typically printed, displayed on-site for viewing, and the most suitable one selected. For another example, when a user needs to repeatedly adjust the size of a 3D product, such as printing flower pots for multiple flowers of different sizes, each flower has a different size, and therefore the flower pots also have different sizes, the size of the product to be printed is typically adjusted in real time based on the measured flower sizes, i.e., the size of the product to be printed is repeatedly adjusted.

[0061] In these scenarios, this embodiment directly resizes images in CLI slices and PRT formats, saving time and improving printing efficiency. Industrial mass printing scenarios typically involve printing numerous products and requiring frequent adjustments. Therefore, the solution in this embodiment significantly improves printing efficiency in these scenarios.

[0062] It is understandable that the printing processing method of the sand mold 3D printing device may also include: When the current PRT format image sub-file is printed, the next CLI format slice is format-converted to obtain the next PRT format image sub-file corresponding to the next CLI format slice.

[0063] From the above content, it can be seen that during the printing process, converting the format while printing can improve printing efficiency.

[0064] In an optional embodiment, in order to further optimize the printing efficiency in scenarios with higher requirements for printing efficiency, such as large-scale 3D printing scenarios, or continuous 3D printing scenarios, in the step of converting the CLI format slice file into the corresponding PRT format image file, when the first CLI format slice file is converted into a PRT format image file, the printer can be directly controlled to print the first PRT format image file. During the printing process of the first PRT format image file, the subsequent CLI format slice files are converted into PRT format image files. After completing the printing task of the first PRT format image file, the memory of the first PRT format image file is released. When repeating the above printing of the current PRT format image file, the operation of converting the next slice from the CLI format file to the PRT format image file is completed. 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 print termination instruction is received.

[0065] This embodiment controls the printer nozzle to start printing after the first cli format slice file is converted into a PRT format image file and before all cli format slice files are converted into PRT format image files. When the first cli format slice file is converted into a PRT format image file, the printer is directly controlled to print the first PRT format image file, which shortens the preprocessing time of printing and improves the efficiency of 3D printing; while the printer is printing, the task of converting the unfinished cli format slice file into a PRT format image file is completed, which shortens the time of the entire printing process and improves the efficiency of 3D printing; when the printing task of the current PRT format image file is completed, the memory of the current PRT format image file is released, saving storage memory; when a print abort command is received, only the task of converting part of the cli format slice file into a PRT format image file is completed, which reduces the task processing amount on the PC side and saves running memory.

[0066] Combine Figure 3 , explaining the overall process of the printing processing method of the sand mold 3D printing equipment: Step 310: Obtain a three-dimensional model of the sand casting product to be printed; the three-dimensional model is an STL file; Step 320: Slice the STL file; Step 330: Generate a cli format slice file and convert it into a PRT format image file; Step 340: Perform 3D printing using a preset grating signal fractional frequency division method; Step 350: Determine the actual sand casting dimensions of the printed product; Step 360: Compare the actual sand casting size with the designed sand casting size; Step 370: Determine whether scaling is required. If scaling is required, proceed to step 371. If scaling is not required, proceed to step 380. Step 371: parse out all vector elements in the CLI format slice file; Step 372: Multiply the coordinate value of each vector element by the scaling factor in the xy direction; Step 373: The image corresponding to the scaled coordinate value is filled with a single color and drawn into a PRT format image file; Step 374: Generate a target PRT format image file; Step 375: Perform 3D printing on the target PRT format image file and proceed to step 380; Step 380: Printing completed.

[0067] In order to improve 3D printing efficiency, the embodiment of the present application first modifies the existing 3D inkjet printing process through the first solution. The process of scaling the size of 3D printed products in the prior art, which requires regenerating a model of a new size and slicing the new model, is improved to a process that does not require regeneration of a new model and no need for re-slicing. The thickness parameters of the original slice and the sanding are directly multiplied by the scaling factor, thereby improving the 3D printing efficiency. The improvement in printing efficiency is particularly obvious in large-scale 3D printing scenarios and large-scale 3D printing scenarios. Based on the above-mentioned improved 3D printing process, this embodiment also provides a second solution, which introduces the technology of grating frequency division to avoid multi-pass printing. By changing the nozzle ignition control method on the board, the printing resolution is met while further improving the printing efficiency, so that the printing efficiency in large-scale 3D printing scenarios and large-scale 3D printing scenarios is better. In the actual production process, relevant personnel can flexibly choose to use the first solution or combine the two solutions according to the specific printing scenario and the requirements for the printing effect.

[0068] The printing processing device of the sand mold 3D printing device provided by the present invention is described below. The printing processing device of the sand mold 3D printing device described below and the printing processing method of the sand mold 3D printing device described above can be referred to each other.

[0069] like Figure 4 As shown, an embodiment of the present invention further provides a printing processing device for a sand mold 3D printing device, which is used to implement the printing processing method for a sand mold 3D printing device in any of the above embodiments. The printing processing device for a sand mold 3D printing device may include: An acquisition module 410 is configured to acquire sand casting product information of the sand casting product to be printed; the sand casting product information at least includes an STL format three-dimensional model corresponding to the sand casting product to be printed and a designed sand casting size; 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; The first processing module 430 is used to convert the CLI format slice file into a corresponding PRT format image file, and when using a sander in a sand mold 3D printing device to perform sand spreading, print the PRT format image file based on a preset grating signal fractional frequency division method to complete printing; a determination module 440 for determining the actual sand casting size of the sand casting product after printing is completed, and determining a scaling factor based on the actual sand casting size and the designed sand casting size; The second processing module 450 is configured to process the cli format slice file based on the scaling factor to obtain a target PRT format image file, and print the target PRT format image file.

[0070] Compared with the prior art, the present invention provides a printing processing method for a sand mold 3D printing device. After slicing the STL format three-dimensional model, the CLI format slice file is converted into a corresponding PRT format image file. In this way, when the actual sand casting size of the printed product differs from the designed sand casting size, the CLI format slice file can be directly adjusted by the scaling factor, without having to readjust the original three-dimensional model and then slice it as in traditional technology. This greatly improves printing efficiency. In addition, a preset grating signal fractional frequency division method is also used in the printing process, which improves printing accuracy, reduces the number of repeated printing adjustments, and further improves printing efficiency.

[0071] In an optional implementation, the second processing module 450 is specifically configured to: Parse all vector elements in the CLI format slice file; Based on the scaling factor, each vector element in all vector elements is processed to obtain a target PRT format image file.

[0072] In an optional implementation, the second processing module 450 is specifically configured to: Multiply the lattice coordinate value obtained by splitting each vector element by the scaling factor to obtain the scaled lattice value; The scaled dot matrix value is filled and drawn into the RPT format image to obtain the target PRT format image file.

[0073] 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 configured to: Determine the frequency division ratio according to printing requirements; When using a sand spreader for sand spreading, the printing carriage in the sand mold 3D printing equipment is controlled based on the frequency division ratio to spray the binder on the sand casting product to be printed, completing the printing of each PRT format image sub-file.

[0074] The first processing module 430 is specifically configured to: Determine the initial resolution and target resolution of the sand casting product to be printed; Based on the initial resolution and the target resolution, the division ratio is determined.

[0075] The first processing module 430 is specifically configured to: Calculate the greatest common divisor of the initial resolution and the target resolution; Substitute the greatest common divisor and the target resolution into the formula: ; The frequency division ratio is calculated; where, is the frequency division ratio, is the target resolution, is the greatest common divisor.

[0076] The printing processing device of the sand mold 3D printing equipment is also used to: when printing the current PRT format image subfile, convert the format of the next CLI format slice to obtain the next PRT format image subfile corresponding to the next CLI format slice.

[0077] like Figure 5 As shown, an embodiment of the present invention further provides an electronic device, which may include: a processor 510, a communication interface 520, a memory 530, and a communication bus. The processor 510, the communication interface 520, and the memory 530 communicate with each other via the communication bus. The memory 530 stores a computer program executable by the processor 510; when the processor 510 executes the computer program, it can execute the printing processing method of the sand mold 3D printing device in any of the above-mentioned embodiments.

[0078] Furthermore, the logic instructions in the aforementioned memory 530 can be implemented as software functional units and, when sold or used as independent products, stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product, stored in a storage medium, includes instructions for causing a computer device (such as a personal computer, server, or network device) to execute all or part of the steps of the various embodiments of the method of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a mobile hard drive, a read-only memory, a random access memory, a magnetic disk, or an optical disk.

[0079] On the other hand, the present invention also provides a non-transitory computer-readable storage medium, in which instructions are stored. When the instructions are executed, the printing processing method of the sand mold 3D printing device in any of the above embodiments is implemented.

[0080] The above embodiments can be implemented in whole or in part using software, hardware, firmware, or any combination thereof. When implemented using software, they can be implemented in whole or in part in the form of a computer program product. A computer program product includes one or more computer programs or instructions. When the computer programs or instructions are loaded and executed on a computer, the processes or functions of the embodiments of the present application are fully or partially executed. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a terminal, a user device, 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, the 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 can be accessed by a computer, or a data storage device such as a server or data center that integrates one or more available media. Available media can be magnetic media, such as floppy disks, hard disks, or magnetic tapes; optical media, such as digital video discs (DVDs); or semiconductor media, such as solid-state drives (SSDs).

[0081] Although the present invention has been described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0082] Although the present invention has been described with reference to specific features and embodiments thereof, it will be apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the invention as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the invention. It will be apparent that various modifications and variations may be made to the present invention by those skilled in the art without departing from the spirit and scope of the invention. Thus, the present invention is intended to include such modifications and variations as fall within the scope of the claims of the present invention and their equivalents.

Claims

1. A printing processing method for a sand mold 3D printing device, characterized in that: include: Acquire sand casting product information of the sand casting product to be printed; the sand casting product information at least includes an STL format three-dimensional model corresponding to the sand casting product to be printed and a designed sand casting size; Slicing the STL format three-dimensional model to obtain a CLI format slice file; the CLI format slice file includes N layers of CLI format slices; wherein N is a positive integer greater than 2; Converting the CLI format slice file into a corresponding PRT format image file, and performing printing processing on the PRT format image file based on a preset grating signal fractional frequency division method when performing sand spreading using a sand spreading device in the sand mold 3D printing device, thereby completing printing; determining an actual sand casting size of the sand casting product after printing is completed, and determining a 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 a target PRT format image file, and the target PRT format image file is printed.

2. The printing processing method of the sand mold 3D printing device according to claim 1, characterized in that: The step of processing the CLI format slice file based on the scaling factor to obtain a target PRT format image file includes: Parse all vector elements in the CLI format slice file; Based on the scaling factor, each vector element in all vector elements is processed to obtain the target PRT format image file.

3. The printing processing method of the sand mold 3D printing device according to claim 2, characterized in that: The step of processing each vector element in all vector elements based on the scaling factor to obtain the target PRT format image file includes: Multiplying the lattice coordinate value obtained by splitting each vector element by the scaling factor to obtain a scaled lattice value; The scaled dot matrix values are filled and drawn into the RPT format image to obtain the target PRT format image file.

4. The printing processing method of the sand mold 3D printing device according to claim 1, characterized in that: The PRT format image file includes N PRT format image sub-files corresponding to the N layers of CLI format slices; The printing process of the PRT format image file based on the preset grating signal fractional frequency division method and the sand spreading device in the sand mold 3D printing device includes: Determine the frequency division ratio according to printing requirements; When the sand spreader is used for spreading sand, the printing carriage in the sand mold 3D printing device is controlled based on the frequency division ratio to spray the binder on the sand casting product to be printed, thereby completing the printing of each PRT format image sub-file.

5. The printing processing method of the sand mold 3D printing device according to claim 4, characterized in that: Determining the frequency division ratio according to printing requirements includes: Determining an initial resolution and a 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.

6. The printing processing method of the sand mold 3D printing device according to claim 5, characterized in that: The determining the frequency division ratio based on the initial resolution and the target resolution includes: Calculating 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 obtained by calculation; wherein, is the frequency division ratio, is the target resolution, is the greatest common divisor.

7. The printing processing method of the sand mold 3D printing device according to claim 4, characterized in that: Also includes: When the current PRT format image sub-file is printed, the format of the next CLI format slice is converted to obtain the next PRT format image sub-file corresponding to the next CLI format slice.

8. A printing processing device for a sand mold 3D printing device, characterized in that: include: An acquisition module is used to acquire sand casting product information of the sand casting product to be printed; the sand casting product information at least includes an STL format three-dimensional model corresponding to the sand casting product to be printed and a designed sand casting size; a slicing module, configured to slice the STL format three-dimensional model to obtain a CLI format slice file; the CLI format slice file includes N layers of CLI format slices; wherein N is a positive integer greater than 2; A first processing module is configured to convert the CLI format slice file into a corresponding PRT format image file, and to print the PRT format image file based on a preset grating signal fractional frequency division method when using a sander in the sand mold 3D printing device to complete printing; a determination module, configured to determine an actual sand casting size of the sand casting product after printing is completed, and determine a 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 a target PRT format image file, and print the target PRT format image file.

9. An electronic device, characterized in that: include: 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 that can be run by the processor; when the processor runs the computer program, it executes the printing processing method of the sand mold 3D printing device according to any one of claims 1 to 7.

10. A computer storage medium, characterized in that The computer storage medium stores instructions, and when the instructions are executed, the printing processing method of the sand mold 3D printing device according to any one of claims 1 to 7 is implemented.

Images