A method for generating path trajectories for additive manufacturing of variable-thickness soft-core supports based on ceramic core free-form surfaces

Abstract

The present invention relates to the field of additive manufacturing technology, and more specifically, to a method for generating a path trajectory for additive manufacturing of variable-thickness soft core struts based on a ceramic core free-form surface. The method comprises: importing a ceramic core model and a fixture model, constructing the soft core strut model at the soft core strut modeling locations determined on the ceramic core model; determining the additive manufacturing process for each soft core strut model on the free-form surface of the ceramic core model; designing a printing model; determining the path trajectory corresponding to each soft core strut model; and determining a final total path trajectory. The present invention reduces non-printing paths, thereby improving printing efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a method for generating a path trajectory for additive manufacturing of a variable-thickness soft core support based on a ceramic core free-form surface. Background Art

[0002] Regarding conformal printing on free-form surfaces. First, the existing slicing software on the market is mainly targeted at 3-axis 3D printers and lacks the processing function for slicing printed objects on free-form surfaces. Second, for customized 3D printers, mainstream slicing software lacks corresponding configuration files, and the generated path trajectories cannot be effectively utilized. Finally, the current trajectory planning for conformal printing mainly focuses on printing circuits using principles such as lasers and inkjets, and there are few path planning methods for additive manufacturing on free-form surfaces using FDM principles.

[0003] The prior art discloses a path trajectory method for 3D printing a single-layer circuit on a free-form surface, which primarily utilizes external force to discretize the circuit to be printed on the surface to obtain point cloud data. The resulting point cloud data is then processed and connected to generate a printing trajectory. A method for generating a single-layer printing trajectory using CAM technology is also disclosed, which primarily involves mapping the designed circuit onto a curved substrate, using CAM technology to generate a CLSF file from the corresponding circuit diagram, and then combining this file with post-processing to generate a printing trajectory. A method for slicing and generating a path trajectory for a curved multi-layer circuit is also disclosed, which primarily involves exporting an EDA design file into a file format recognizable by MCAD, performing a wrapping design on the model, and then generating a printing path trajectory for the curved multi-layer circuit using MCAD software.

[0004] However, the main path planning methods for common printing on free-form surfaces are currently to use traditional CAM milling processes to generate paths, or to use discrete point cloud data to generate printing paths, but most of these methods focus on single-layer printing. For multi-layer printing on curved surfaces, the currently generated printing paths are based on traditional subtractive manufacturing to generate printing trajectories, but the neutral files generated require a lot of work to change the tool sequence to adapt to additive manufacturing. Therefore, their existence results in a large workload for programmers and low efficiency, especially for the problem of inaccurate printing path trajectory generation for complex products.

[0005] Based on the above problems, the present invention proposes to use the latest additive manufacturing module of UG / NX software to solve the printing path trajectory planning problem of additive manufacturing of variable thickness soft core supports on ceramic core free-form surfaces. Summary of the Invention

[0006] The present invention provides a method for generating a path trajectory for additive manufacturing of a variable-thickness soft core support based on a ceramic core free-form surface, so as to solve the problem that the existing technology uses a traditional CAM milling process to generate a path, or uses a discrete point cloud data method to generate a printing path, but most of these methods focus on single-layer printing; for the need for multi-layer printing on a curved surface, the currently generated printing path is based on traditional subtractive manufacturing to generate a printing trajectory, but the generated neutral file still requires a lot of work to change the tool path sequence to adapt to additive manufacturing. Therefore, its existence causes a large workload for programmers and low efficiency, especially for the problem of inaccurate generation of printing path trajectories for complex products.

[0007] The present invention provides a method for generating a path trajectory for additive manufacturing of a variable thickness soft core support based on a ceramic core free-form surface, which adopts the following technical solutions, including:

[0008] Importing the ceramic core model and the fixture model into the 3D modeling software, performing fluid analysis on the ceramic core model to obtain the soft core support modeling position points, clamping the ceramic core model in the fixture model and performing variable thickness soft core support entity modeling at the soft core support modeling position points according to the design dimensions of the soft core support to obtain the soft core support models corresponding to the soft core support modeling position points;

[0009] A machining reference coordinate system is set, and the additive manufacturing process of each soft core support model on the free-form surface of the ceramic core model is sequentially obtained using the additive manufacturing module of the 3D software in the machining reference coordinate system;

[0010] According to the external dimensions of the print head used in the additive manufacturing process, a print head envelope block with the same external dimensions used for path planning is established, and a printing model is designed;

[0011] The free-form surface of the ceramic core model is used as the printing base surface, and the additive manufacturing module of the 3D software is used to plan the path trajectory of each soft core support model under the additive manufacturing process corresponding to the soft core support model to obtain the initial path trajectory corresponding to each soft core support model;

[0012] Using the printing model to perform printing simulation on the soft core support model according to the initial path trajectory, and determining the path trajectory corresponding to each soft core support model based on whether there is interference between the print head and the ceramic core model, or between the print head and the fixture model;

[0013] The path trajectories of all soft core support models are spliced ​​in sequence to generate a total path trajectory. The printing model is used to perform printing simulation of the soft core support model according to the total path trajectory. The final total path trajectory is determined based on whether there is interference between the printing nozzle and the ceramic core model, or between the printing nozzle and the fixture model during the printing simulation of the soft core support model according to the total path trajectory.

[0014] Preferably, each soft core support model and the ceramic core model are set as different entities.

[0015] Preferably, the steps of performing fluid analysis on the ceramic core model to obtain the soft core support modeling position points are:

[0016] Extract multiple stress concentration areas in the force distribution diagram;

[0017] Select any point in the stress concentration area as the soft core support modeling point.

[0018] Preferably, the steps of establishing a machining reference coordinate system for each soft core support model are:

[0019] The origins of all soft core support models are defined as the same origin; and the X, Y, and Z coordinate systems of the machining reference coordinate system follow the right-handed Cartesian coordinate system.

[0020] Preferably, the steps of performing printing simulation on each soft core support model in sequence according to the initial path trajectory are:

[0021] According to the external dimensions of the print head used in the additive manufacturing process, a print head envelope block with the same external dimensions used for path planning is established;

[0022] According to the established print head envelope block, each soft core support model is printed and simulated in turn according to the initial path trajectory in the simulation model.

[0023] Preferably, the step of determining the path trajectory corresponding to each soft core support model is:

[0024] If the print head interferes with the ceramic core model and the fixture model, the initial path trajectory is regenerated until the print head does not interfere with the ceramic core model and the fixture model under the regenerated initial path trajectory. The initial path trajectory without interference is used as the path trajectory corresponding to each soft core support model;

[0025] If there is no interference between the print head and the ceramic core model and the fixture model, the initial path trajectory is used as the path trajectory corresponding to each soft core support model.

[0026] Preferably, the steps of determining the final total path trajectory are:

[0027] If the print head interferes with the ceramic core model and the fixture model, the total path trajectory is regenerated until the print head and the ceramic core model are regenerated, and the print head and the fixture model do not interfere with each other. The total path trajectory without interference is used as the final total path trajectory.

[0028] If there is no interference between the print head and the ceramic core model, or between the print head and the fixture model, the total path trajectory without interference is taken as the final total path trajectory.

[0029] Preferably, the steps of sequentially splicing the path trajectories of all the soft core support models to generate a total path trajectory are:

[0030] Number all soft core support models in sequence;

[0031] Connect the end point of the path track corresponding to the first numbered soft core support model with the starting point of the path track corresponding to the next numbered soft core support model in the order of numbering, and so on. Connect the path tracks corresponding to all soft core support models in the order of numbering to form a total path track.

[0032] Preferably, the method further includes: generating a tool location file according to the final total path trajectory; converting the generated tool location file into an NC code recognizable by the additive manufacturing device; and inputting the NC code into the additive manufacturing device for manufacturing.

[0033] The beneficial effects of the present invention are:

[0034] By directly performing 3D modeling of a variable thickness soft core support on the free-form surface of the ceramic core model in the 3D software, and then switching to the built-in CAM module for printing path trajectory planning, the data loss caused by data transmission between different software systems can be reduced; the final total path trajectory is determined based on interference analysis, that is, different processing reference coordinate systems are set and the origin positions of all processing reference coordinate systems are the same, and then the path trajectories of all soft core support models are spliced ​​in sequence to generate a total path trajectory. For the printing of a single soft core support, there are four position points, namely the starting point of the additive manufacturing trajectory, the start printing point, the end printing point, and the end point of the additive manufacturing trajectory. When the path trajectory is made into a total path trajectory, the path from the end printing point to the end point of the additive manufacturing trajectory is reduced, thereby improving printing efficiency and reducing non-printing paths, thereby improving printing efficiency.

[0035] Secondly, the present invention performs trajectory planning for soft core support additive manufacturing on the free-form surface of the ceramic core model. Different free-form surfaces can be set to realize direct additive manufacturing on the surface of any complex structure. By adjusting the rotation angle of the rotation axis of the machine tool, it can be ensured that the surface and the print head are always in a vertical state at the printing position point, thereby achieving high-speed and simple printing. After obtaining the final total path trajectory, the programmer only needs to convert the CLSF file into NC code that can be recognized by the additive manufacturing equipment, so that the NC code can be used to accurately control the movement of each motion axis of the additive manufacturing equipment, thereby achieving precise control of printing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 This is a flow chart of a method for generating a path trajectory for additive manufacturing of a variable thickness soft core support based on a ceramic core free-form surface according to the present invention;

[0038] Figure 2 Schematic diagram of the ceramic core model being clamped in the fixture model in this embodiment;

[0039] Figure 3 1 is a modeling diagram of the soft core support model on the free-form surface of the ceramic core model in this embodiment;

[0040] Figure 4 Schematic diagram of the structure of the print head envelope block in this embodiment;

[0041] Figure 5 This is a path trajectory diagram of a single soft core support model in this embodiment for additive manufacturing printing;

[0042] Figure 6 1 is a trajectory diagram of the additive manufacturing printing of different soft core support models in a single process in this embodiment;

[0043] Figure 7 1 is a path trajectory diagram of additive manufacturing printing of different soft core support models under multiple processes in this embodiment;

[0044] Figure 8 Schematic diagram of the additive manufacturing process menu for all soft core support models in this embodiment;

[0045] Figure 9 Schematic diagram of setting simulation conditions for interference analysis in this embodiment;

[0046] Figure 10 This is a schematic diagram of generating a CLSF file in this embodiment;

[0047] Figure 11 It is a schematic diagram of generating NC code in this embodiment. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] An embodiment of a method for generating a path trajectory for additive manufacturing of a variable thickness soft core support based on a ceramic core free-form surface of the present invention is as follows: Figure 1 Shown, including:

[0050] S1. Import the ceramic core model and the fixture model, and build the soft core support model at the soft core support modeling position points determined on the ceramic core model;

[0051] Specifically, the ceramic core model and the fixture model are imported into 3D modeling software such as UG or NX, and the fluid analysis of the ceramic core model is performed to obtain the soft core support modeling position points. The ceramic core model is clamped in the fixture model and the variable thickness soft core support is solidified and modeled according to the design size of the soft core support at the soft core support modeling position points to obtain the soft core support models corresponding to each soft core support modeling position point. It should be noted that each soft core support model and the ceramic core model need to be set as different entities to facilitate the subsequent selection and numbering of different soft core support models.

[0052] Specifically, the steps of clamping the ceramic core model in the fixture model are as follows: clamping the ceramic core model according to the preset clamping position points of the ceramic core model, and the ceramic core model in the clamped state is as follows: Figure 2 shown.

[0053] like Figure 3 As shown, the size of the soft core support model is 5 cylinders with a diameter of 5 mm and cylinders with heights ranging from 1 to 3 mm. In this embodiment, after the soft core support models are numbered, the height of soft core support model No. 1 is 1.4 mm; the height of soft core support model No. 2 is 1.6 mm; the height of soft core support model No. 3 is 1.7 mm; the height of soft core support model No. 4 is 2.2 mm; and the height of soft core support model No. 5 is 2.8 mm.

[0054] S2. determining an additive manufacturing process for each soft core support model on the free-form surface of the ceramic core model;

[0055] Specifically, a machining reference coordinate system is set, and the additive manufacturing process of each soft core support model on the free-form surface of the ceramic core model is sequentially obtained using the additive manufacturing module of the three-dimensional software in the machining reference coordinate system.

[0056] In this embodiment, in the CAM module of the 3D software, the additive manufacturing module is called to establish an MCS coordinate system (machining reference coordinate system). For each soft core support model, under the established machining reference coordinate system, the additive manufacturing module of the 3D software is used to sequentially obtain the additive manufacturing process (FREEFORM_ADDITIVE process) of each soft core support model on the free surface of the ceramic core model, such as Figure 8 As shown, a schematic diagram of the additive manufacturing process menu corresponding to each soft core support model is shown.

[0057] S3, design printing model;

[0058] According to the external dimensions of the print head used in the additive manufacturing process, a print head envelope block with the same external dimensions used for path planning is established, and a printing model is designed based on the print head envelope block, such as Figure 4 As shown, the dimensions of the printed model must be exactly the same as the actual object to facilitate subsequent interference checks. The print head type is set to MATERIAL_EXTRUDER, which is consistent with the principle type in the actual printing process.

[0059] S4, determining the path trajectory corresponding to each soft core support model;

[0060] Specifically, the free-form surface of the ceramic core model is used as the printing base surface, and the additive manufacturing module of the three-dimensional software is used to plan the path trajectory of each soft core support model under the additive manufacturing process corresponding to the soft core support model to obtain the initial path trajectory corresponding to each soft core support model; the soft core support model is printed and simulated according to the initial path trajectory, and the path trajectory corresponding to each soft core support model is determined based on whether there is interference between the printing nozzle and the ceramic core model, or between the printing nozzle and the fixture model.

[0061] In this embodiment, first, before planning the path trajectory of a single soft core support model, it is necessary to determine the printing reference surface and filler characteristics, select boundary conditions, and specify the printing range and printing position. That is, the free-form surface of the ceramic core model is used as the printing base surface, and the shape and size of the soft core support model to be printed are determined according to the filler characteristics, boundary conditions, and the specified printing range. Secondly, since the additive manufacturing equipment is a four-axis B Reinaker CNC system, the output axis is set to a four-axis, perpendicular to the free-form surface, such as Figure 10 As shown in the figure, the j value in i, j, and k in the generated CLSF file is 0; since the soft core support is a cylinder, the spiral printing strategy is selected, printing from the inside out, and the printing layer thickness is set to 0.24mm (the print nozzle diameter is 0.3mm, and 80% of the print nozzle diameter will have higher printing quality). The printing speed is set to 40mm / s to adapt to the extrusion speed of the nozzle; finally, the initial path trajectory of a single soft core support model is generated, as shown in the figure. Figure 5As shown, the soft core support model is printed and simulated according to the obtained initial path trajectory. If the print head interferes with the ceramic core model and the fixture model, the initial path trajectory is regenerated until the print head does not interfere with the ceramic core model and the fixture model under the regenerated initial path trajectory. The initial path trajectory without interference is used as the path trajectory corresponding to each soft core support model; if the print head does not interfere with the ceramic core model and the fixture model, the initial path trajectory is used as the path trajectory corresponding to each soft core support model.

[0062] S4, determining the final total path trajectory;

[0063] Since the additive manufacturing module in UG 3D software lacks the function of sequential printing of multiple targets on the same reference plane, if all the soft core supports are placed in the same coordinate system and the trajectory planning of the soft core support model is performed at the same time, the generated path trajectory is as follows Figure 6 As shown, Figure 6 The conventional method shown in FIG2 needs to perform a printing simulation of the soft core support model according to the path trajectory corresponding to one of the additive manufacturing processes during printing. After completion, the print head of the printing device is reset and the printing simulation of the soft core support model is restarted according to the path trajectory corresponding to the other additive manufacturing process. Figure 6 A large number of redundant non-printing sections appear in the process, which greatly reduces the printing efficiency. Therefore, on the basis of establishing a processing reference coordinate system for each soft core support model in step S2, the path trajectories of all soft core support models are sequentially spliced ​​to generate a coordinate system as shown in FIG. Figure 7 The total path trajectory shown in the figure only requires the printing model to be simulated according to the total path trajectory during printing, thus avoiding the occurrence of non-printing paths. The final total path trajectory is determined based on whether the printing nozzle and the ceramic core model, or the printing nozzle and the fixture model interfere with each other during the printing simulation of the soft core support model according to the total path trajectory.

[0064] Among them, the step of determining the path trajectory corresponding to each soft core support model is: if the print head interferes with the ceramic core model and the fixture model, the initial path trajectory is regenerated until the print head does not interfere with the ceramic core model and the fixture model under the regenerated initial path trajectory, and the initial path trajectory without interference is used as the path trajectory corresponding to each soft core support model; if the print head does not interfere with the ceramic core model and the fixture model, the initial path trajectory is used as the path trajectory corresponding to each soft core support model, such as Figure 9 As shown in the figure, it is a schematic diagram of the simulation condition settings for interference analysis during printing simulation.

[0065] It should be noted that the path trajectory under the additive manufacturing process corresponding to each soft core support model is connected by connecting the end point of the path trajectory corresponding to the first numbered soft core support model with the starting point of the path trajectory corresponding to the next numbered soft core support model according to the numbering order of the soft core support models, and so on. The path trajectories corresponding to all soft core support models are spliced ​​in sequence according to the numbering order to form a total path trajectory.

[0066] Specifically, it also includes: generating the following according to the final total path trajectory: Figure 10 The tool location file (CLSF file) shown in the figure is processed using the developed post-processing pui file to obtain the following Figure 11 The NC code shown can be recognized by the additive manufacturing equipment; the soft core support can be manufactured by inputting the NC code into the additive manufacturing equipment.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for generating a path trajectory for additive manufacturing of a variable thickness soft core support based on a ceramic core free-form surface, characterized in that: include: Importing the ceramic core model and the fixture model into the 3D modeling software, performing fluid analysis on the ceramic core model to obtain the soft core support modeling position points, clamping the ceramic core model in the fixture model and performing variable thickness soft core support entity modeling at the soft core support modeling position points according to the design dimensions of the soft core support to obtain the soft core support models corresponding to the soft core support modeling position points; A machining reference coordinate system is set, and the additive manufacturing process of each soft core support model on the free-form surface of the ceramic core model is sequentially obtained using the additive manufacturing module of the 3D software in the machining reference coordinate system; According to the external dimensions of the print head used in the additive manufacturing process, a print head envelope block with the same external dimensions used for path planning is established, and a printing model is designed; The free-form surface of the ceramic core model is used as the printing base surface, and the additive manufacturing module of the 3D software is used to plan the path trajectory of each soft core support model under the additive manufacturing process corresponding to the soft core support model to obtain the initial path trajectory corresponding to each soft core support model; Using the printing model to perform printing simulation on the soft core support model according to the initial path trajectory, and determining the path trajectory corresponding to each soft core support model based on whether there is interference between the print head and the ceramic core model, or between the print head and the fixture model; The path trajectories of all soft core support models are spliced ​​in sequence to generate a total path trajectory. The printing model is used to perform printing simulation of the soft core support model according to the total path trajectory. The final total path trajectory is determined based on whether there is interference between the printing nozzle and the ceramic core model, or between the printing nozzle and the fixture model during the printing simulation of the soft core support model according to the total path trajectory.

2. The method for generating a path trajectory for additive manufacturing of a variable thickness soft core support based on a ceramic core free-form surface according to claim 1, characterized in that: Set each soft core support model and ceramic core model as different entities.

3. The method for generating a path trajectory for additive manufacturing of a variable thickness soft core support based on a ceramic core free-form surface according to claim 1, characterized in that: The steps for performing fluid analysis on the ceramic core model to obtain the soft core support modeling location points are as follows: Moldflow software was used to simulate the impact of the wax material on the ceramic core model during the wax pressing process, and the force distribution diagram at different positions on the surface of the ceramic core model was obtained; Extract multiple stress concentration areas in the force distribution diagram; Select any point in the stress concentration area as the soft core support modeling point.

4. The method for generating a path trajectory for additive manufacturing of a variable thickness soft core support based on a ceramic core free-form surface according to claim 1, characterized in that: The X, Y, and Z coordinate systems of the machining reference coordinate system follow the right-handed Cartesian coordinate system.

5. The method for generating a path trajectory for additive manufacturing of a variable thickness soft core support based on a ceramic core free-form surface according to claim 1, characterized in that: Steps for printing simulation of each soft core support model in turn according to the initial path trajectory: According to the external dimensions of the print head used in the additive manufacturing process, a print head envelope block with the same external dimensions used for path planning is established; According to the established print head envelope block, each soft core support model is printed and simulated in turn according to the initial path trajectory in the simulation model.

6. The method for generating a path trajectory for additive manufacturing of a variable thickness soft core support based on a ceramic core free-form surface according to claim 1, characterized in that: The steps for determining the path trajectory corresponding to each soft core support model are: If the print head interferes with the ceramic core model and the fixture model, the initial path trajectory is regenerated until the print head does not interfere with the ceramic core model and the fixture model under the regenerated initial path trajectory. The initial path trajectory without interference is used as the path trajectory corresponding to each soft core support model; If there is no interference between the print head and the ceramic core model and the fixture model, the initial path trajectory is used as the path trajectory corresponding to each soft core support model.

7. The method for generating a path trajectory for additive manufacturing of a variable thickness soft core support based on a ceramic core free-form surface according to claim 1, characterized in that: The steps to determine the final total path trajectory are: If the print head interferes with the ceramic core model and the fixture model, the total path trajectory is regenerated until the print head and the ceramic core model are regenerated, and the print head and the fixture model do not interfere with each other. The total path trajectory without interference is used as the final total path trajectory. If there is no interference between the print head and the ceramic core model, or between the print head and the fixture model, the total path trajectory without interference is taken as the final total path trajectory.

8. The method for generating a path trajectory for additive manufacturing of a variable thickness soft core support based on a ceramic core free-form surface according to claim 1, characterized in that: The steps for sequentially splicing the path trajectories of all soft core support models to generate a total path trajectory are as follows: Number all soft core support models in sequence; Connect the end point of the path track corresponding to the first numbered soft core support model with the starting point of the path track corresponding to the next numbered soft core support model in the order of numbering, and so on. Connect the path tracks corresponding to all soft core support models in the order of numbering to form a total path track.

9. The method for generating a path trajectory for additive manufacturing of a variable thickness soft core support based on a ceramic core free-form surface according to claim 1, characterized in that: Also includes: Generate a tool path file based on the final total path trajectory; transform the generated tool path file into NC code that can be recognized by the additive manufacturing equipment; Input the NC code into the additive manufacturing equipment for manufacturing.

Images