3D printing additive and subtractive composite manufacturing equipment and forming method

Abstract

The invention discloses 3D printing additive and subtractive composite manufacturing equipment and a forming method. The 3D printing additive and subtractive composite manufacturing equipment comprises a forming platform, a rotary driving mechanism, an extrusion unit, a subtractive unit and a three-dimensional linkage mechanism. The forming platform is used for bearing and fixing a printing base body. The output end of the rotation driving mechanism is connected with the forming platform and used for driving the forming platform to rotate around the central axis perpendicular to the bearing plane of the forming platform. The extrusion unit is arranged above the forming platform and is provided with an extrusion end capable of directionally extruding a molten or semi-molten printing material; the material reducing unit is arranged above or on the side portion of the forming platform, and the emitting direction of the laser emitting end of the material reducing unit faces the forming platform. High polymer materials are processed through non-contact laser energy, damage to material performance caused by high temperature generated by friction during contact processing of a traditional milling cutter is effectively avoided, and meanwhile, laser cutting has higher processing precision and efficiency.

Description

Technical Field

[0001] This invention relates to the field of medical device printing technology, specifically to a 3D printing additive and subtractive composite manufacturing equipment and molding method. Background Technology

[0002] With the development of medical 3D printing technology, customized assistive medical devices are better suited to the current market demand. 3D printing technology can rapidly manufacture highly functional, complex, and aesthetically pleasing assistive medical devices without design limitations, solving the problems of low efficiency, poor comfort, and poor economy associated with traditional manufacturing methods.

[0003] Current 3D printing manufacturing of braces and orthotics can guarantee precision and aesthetics, but it is inefficient. The materials used in braces and orthotics are polymers, and during large-scale, rapid, one-piece printing, especially when the printed model contains holes, problems such as poor boundary forming accuracy and uneven surface smoothness occur, affecting aesthetics and usability. Rapidly prototyping large-scale models adds a post-processing step to increase the model's forming accuracy, but this is time-consuming and labor-intensive. Chinese Patent 202210866206.7 discloses a 3D printing and milling integrated additive and subtractive manufacturing machine for polymer materials, which achieves additive manufacturing through a 3D printing module and subtractive manufacturing through a milling module, realizing a rapid and high-precision additive and subtractive manufacturing process for polymer materials.

[0004] However, when this solution is actually applied to polymer materials, the method of using a milling cutter to contact the polymer material during the subtractive manufacturing process can easily generate high temperatures, which can affect the subtractive effect of the polymer material. In addition, the process usually requires switching to the subtractive process after each printing layer is completed, and the frequent process switching seriously reduces the overall molding efficiency. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a 3D printing additive-subtractive composite manufacturing equipment and molding method, which solves the technical problems in the prior art where high temperatures are easily generated when milling cutters are used to process polymer materials, affecting the processing effect, and where frequent process alternation leads to low molding efficiency.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a 3D printing additive-subtractive composite manufacturing equipment, comprising a forming platform, a rotary drive mechanism, an extrusion unit, a subtractive unit, and a three-dimensional linkage mechanism; the forming platform is used to support and fix the printing substrate; the output end of the rotary drive mechanism is connected to the forming platform and is used to drive the forming platform to rotate around a central axis perpendicular to its supporting plane; the extrusion unit is located above the forming platform and has an extrusion end capable of directionally extruding molten or semi-molten printing material; the subtractive unit is located above or to the side of the forming platform, with the emission direction of its laser emission end facing the forming platform, and is used to selectively laser cut, mill, or engrave the printing substrate; the three-dimensional linkage mechanism is connected to at least one of the forming platform, the extrusion unit, and the subtractive unit, and is used to drive the forming platform, the extrusion unit, and the subtractive laser device to perform multi-degree-of-freedom relative motion in three-dimensional space.

[0007] In some embodiments, the three-dimensional linkage mechanism includes an additive motion mechanism, a subtractive motion mechanism, and a lifting motion mechanism; the output end of the additive motion mechanism is connected to the extrusion unit and is used to drive the extrusion unit to perform translational motion in a plane; the output end of the subtractive motion mechanism is connected to the subtractive unit and is used to drive the subtractive unit to perform translational motion in a plane; the output end of the lifting motion mechanism is connected to the molding platform and is used to drive the molding platform to perform lifting motion in a direction perpendicular to its supporting plane.

[0008] In some embodiments, the additive motion mechanism includes a Y-axis motion structure and an X-axis motion structure; The Y-axis motion structure is arranged in the horizontal direction, and its moving end is connected to the X-axis motion structure to drive the X-axis motion structure to translate along the Y-axis direction. The X-axis motion structure is arranged in a horizontal direction perpendicular to the Y-axis, and its moving end is connected to the extrusion unit to drive the extrusion unit to translate along the X-axis direction.

[0009] In some embodiments, the subtractive motion mechanism includes a radial motion structure and a transverse motion structure; the radial motion structure is arranged in a horizontal direction, and its moving end is connected to the transverse motion structure for driving the transverse motion structure to translate in the radial direction; the transverse motion structure is arranged in a horizontal direction perpendicular to the radial direction, and its moving end is connected to the subtractive unit for driving the subtractive unit to translate in the transverse direction.

[0010] In some embodiments, the lifting mechanism includes at least two sets of lead screw lifting structures and at least two lifting platforms; at least two sets of lead screw lifting structures are respectively disposed on both sides of the forming platform, and their lifting drive ends are connected to the corresponding lifting platforms; at least two lifting platforms are connected to the forming platform to drive the lifting platforms to move vertically under the synchronous drive of the lead screw lifting structures.

[0011] In some embodiments, the rotary drive mechanism includes a platform support frame and a rotary drive component; the platform support frame has a plurality of support portions extending radially along the molding platform, and each of the support portions is arranged in a ring array with respect to the central axis of the molding platform; The rotary drive is connected to the platform support frame, and its output shaft is collinear with the central axis of the forming platform, used to drive the platform support frame to rotate the forming platform around the central axis.

[0012] In some embodiments, the extrusion unit includes an extrusion nozzle, an extrusion drive assembly, and an extrusion cooling fan; the extrusion nozzle is disposed corresponding to the forming platform, and a flow channel for conveying printing material is formed inside it; the extrusion drive assembly is connected to the flow channel of the extrusion nozzle and is used to push the printing material to the extrusion nozzle at a preset pressure and speed; the extrusion cooling fan is disposed on the side of the extrusion nozzle, and its air outlet faces the extrusion end of the extrusion nozzle, and is used to cool and shape the extruded printing material.

[0013] In some embodiments, the subtractive material unit includes a focusing head, a reflecting component, and a laser; the laser emitting end of the focusing head is positioned facing the forming platform, and its interior is provided with a focusing lens group for converging the laser beam; the reflecting component includes at least two reflecting modules, which are sequentially arranged on the optical path between the laser and the focusing head to change the laser transmission direction of the laser and guide the laser beam to the focusing head.

[0014] Secondly, the present invention also provides a 3D printing additive-subtractive composite molding method, comprising the 3D printing additive-subtractive composite manufacturing equipment as described in any one of the above claims, the method comprising: Separate the solid 3D printing model without holes from the original 3D model, and extract the hole outline and the outer boundary outline to generate the corresponding 3D printing path and laser cutting path respectively. The solid 3D printed model is imported into the 3D printing additive and subtractive composite manufacturing equipment. While the rotary drive mechanism drives the work platform to rotate, the extrusion unit extrudes the material according to the preset printing parameters. In conjunction with the 3D linkage mechanism, the material is stacked layer by layer along the planned path to quickly form a solid model without holes. The laser subtractive cutting paths are classified into small hole paths, large hole paths, and outer contour boundary paths; and laser processing parameters are set to match the different types of paths. Based on the classification path and matching parameters, the subtractive material unit is activated, and the three-dimensional linkage mechanism is controlled to drive the subtractive material unit, so that the laser focusing head moves along the surface contour of the solid blank; the holes and contours on the solid model are laser-cut to finally obtain the finished structural product.

[0015] In some embodiments, during the laser cutting process: For the path of the small hole, the laser focus is controlled to scan and cut along a circular trajectory with the center point of the hole as the center. For the large hole path and the outer contour boundary path, the laser focus is controlled to be offset along the normal direction of each discrete point on the contour to form a cutting trajectory equidistant from the original contour.

[0016] Compared with existing technologies, the 3D printing additive and subtractive composite manufacturing equipment and molding method provided by this invention, by setting up a rotatable molding platform, and cooperating with a three-dimensional linkage mechanism to drive the extrusion unit and the non-contact laser subtractive unit to work together, after completing the overall additive deposition of the solid model, the subtractive unit is used to perform precise laser cutting on the holes and outer contours, avoiding the high temperature damage of traditional milling, and reducing the number of process changes. It effectively solves the problems in existing technologies where high temperatures caused by contact milling during 3D printing subtractive processing of polymer materials easily affect material properties and the low molding efficiency caused by frequent process changes, significantly improving the molding accuracy and production efficiency of complex structural parts such as medical assistive devices. Attached Figure Description

[0017] Figure 1 This is a frontal three-dimensional structural diagram of the 3D printing additive and subtractive composite manufacturing equipment and molding method provided in the embodiments of the present invention; Figure 2 This is a schematic diagram of the overall back three-dimensional structure of the 3D printing additive and subtractive composite manufacturing equipment and molding method provided in the embodiments of the present invention; Figure 3 This is a three-dimensional structural diagram of the molding platform and rotary drive mechanism installed in the 3D printing additive and subtractive composite manufacturing equipment and molding method provided in the embodiments of the present invention; Figure 4 This is a three-dimensional structural diagram of the subtractive unit and subtractive motion mechanism of the 3D printing additive and subtractive composite manufacturing equipment and molding method provided in the embodiments of the present invention; Figure 5 yes Figure 1 Enlarged structural diagram at point A in the middle.

[0018] Explanation of reference numerals in the attached figures: 1. Molding platform; 2. Rotary drive mechanism; 21. Rotary drive component; 211. Electric rotary table; 22. Platform support frame; 23. Platform support rod. 3. Extrusion unit; 31. Extrusion servo motor; 32. Extrusion single screw module; 33. Extrusion nozzle; 34. Extrusion cooling fan. 4. Subtractive manufacturing unit; 41. Laser; 42. Focusing head; 43. First reflecting device; 44. Second reflecting device; 45. Third reflecting device; 46. Fourth reflecting device; 47. Support plate. 5. Three-dimensional linkage mechanism; 51. Additive motion mechanism; 511. Y-axis motion structure; 512. X-axis motion structure; 52. Subtractive motion mechanism; 521. Radial motion structure; 522. Lateral motion structure; 53. Lifting motion mechanism; 531. Lifting servo motor; 532. Drive screw; 533. Optical axis; 6. Overall framework; 7. Operation screen. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] To address the technical problems of high temperatures affecting processing results when using milling cutters to process polymer materials in 3D printing additive-subtractive composite manufacturing equipment, and low forming efficiency due to frequent process alternation, this invention provides a 3D printing additive-subtractive composite manufacturing equipment and forming method. This method uses non-contact laser energy to process polymer materials, effectively avoiding the damage to material properties caused by high temperatures from friction during traditional milling cutter processing. Simultaneously, laser cutting offers higher processing precision and efficiency. In terms of the forming method, a hole-free solid model is first rapidly formed through additive manufacturing, followed by concentrated subtractive cutting to remove holes and contours. This reduces the frequent switching between additive and subtractive processes, significantly improving overall forming efficiency.

[0021] Please see Figures 1 to 3In a first aspect, embodiments of this application provide a 3D printing additive-subtractive composite manufacturing equipment, including a forming platform 1, a rotary drive mechanism 2, an extrusion unit 3, a subtractive unit 4, and a three-dimensional linkage mechanism 5; the forming platform 1 is used to support and fix the printing substrate; the output end of the rotary drive mechanism 2 is connected to the forming platform 1 and is used to drive the forming platform 1 to rotate around a central axis perpendicular to its supporting plane; the extrusion unit 3 is located above the forming platform 1 and has an extrusion end capable of directionally extruding molten or semi-molten printing material; the subtractive unit 4 is located above or to the side of the forming platform 1, with the emission direction of its laser emission end facing the forming platform 1, and is used to selectively laser cut, mill, or carve the printing substrate; the three-dimensional linkage mechanism 5 is connected to at least one of the forming platform 1, the extrusion unit 3, and the subtractive unit 4, and is used to drive the forming platform 1, the extrusion unit 3, and the subtractive laser device to perform multi-degree-of-freedom relative motion in three-dimensional space.

[0022] In this device, the output end of the rotary drive mechanism 2 is connected to the forming platform 1. The rotary drive mechanism 2 can drive the forming platform 1 to rotate, enabling the forming platform 1 to rotate continuously 360 degrees during the printing process. The three-dimensional linkage mechanism 5 is connected to at least one of the forming platform 1, the extrusion unit 3, and the subtractive processing unit 4. The cooperation between the rotary drive mechanism 2 and the three-dimensional linkage mechanism 5 enables the forming platform 1 to achieve multi-degree-of-freedom relative motion with the extrusion unit 3 and the subtractive processing unit 4, which is convenient for handling support and orthotic structures with rotational symmetry or complex spatial curves. The extrusion unit 3 can construct the three-dimensional structure of the printing substrate layer by layer on the rotating forming platform 1 by directionally extruding molten or semi-molten printing material. The subtractive processing unit 4 adopts a non-contact laser processing method, avoiding the high temperature problem caused by the contact between traditional milling processes and polymer materials. By focusing the laser energy precisely on the processing area through a focusing lens group, high-precision cutting, engraving, and contour trimming of the printing substrate are achieved.

[0023] To achieve integrated installation of each module, please refer to [link / reference]. Figure 1 and Figure 2 In this embodiment, the equipment also includes an overall frame 6, which is a frame structure built with high-strength aluminum alloy profiles. The modular design reserves installation positions for the forming platform 1, the rotary drive mechanism 2, the extrusion unit 3 and the subtractive material unit 4.

[0024] To further improve the dynamic performance and machining accuracy of the equipment, please refer to [link / reference]. Figure 1 and Figure 2In some possible embodiments, the three-dimensional linkage mechanism 5 includes an additive motion mechanism 51, a subtractive motion mechanism 52, and a lifting motion mechanism 53. The output end of the additive motion mechanism 51 is connected to the extrusion unit 3, and is used to drive the extrusion unit 3 to perform translational motion in a plane. The output end of the subtractive motion mechanism 52 is connected to the subtractive unit 4, and is used to drive the subtractive unit 4 to perform translational motion in a plane. The output end of the lifting motion mechanism 53 is connected to the forming platform 1, and is used to drive the forming platform 1 to perform lifting motion in a direction perpendicular to its supporting plane. Through this design, the forming platform 1 can achieve precise height adjustment through the lifting motion mechanism 53. The extrusion unit 3 and the subtractive unit 4 can respectively complete translation in a plane through the independent additive motion mechanism 51 and the subtractive motion mechanism 52, which can realize the three-dimensional spatial movement of the forming platform 1 relative to the extrusion unit 3 and the subtractive unit 4. At the same time, combined with the rotation function of the rotary drive mechanism 2, the relative positional relationship between the printing substrate and the processing device can be flexibly adjusted.

[0025] In actual processing, when additive manufacturing is required, the additive motion mechanism 51 drives the extrusion unit 3 to be precisely positioned in the plane. The extrusion unit 3 extrudes printing material according to a preset path, and in conjunction with the rotation and lifting motion of the forming platform 1, it accumulates layer by layer to form a basic structure with complex curved surfaces or rotational features. After additive printing is completed, the subtractive motion mechanism 52 drives the subtractive unit 4 to move to the designated processing area of ​​the printed substrate. The laser emitting end emits a laser beam according to the processing path to selectively cut, mill, or engrave excess material on the surface of the printed substrate to correct printing accuracy errors and form a smooth surface. During this process, the rotation drive mechanism 2 can drive the forming platform 1 to rotate continuously or intermittently according to processing requirements, so that laser processing can evenly cover the outer surface or inner contour of the rotationally symmetrical structure; the lifting motion mechanism 53 can adjust the height of the forming platform 1 in real time to ensure that the laser focus is always at the optimal processing plane, realizing seamless connection between additive and subtractive processes, and effectively improving overall processing efficiency and forming quality.

[0026] Please see Figure 1 and Figure 2In one possible embodiment, the additive motion mechanism 51 consists of an X-axis motion structure 512 and a Y-axis motion structure 511. Both the X-axis motion structure 512 and the Y-axis motion structure 511 employ high-precision linear modules, which are automated motion units composed of linear guides, ball screws, and other components. Two sets of Y-axis motion structures 511 are arranged side-by-side on the top two sides of the overall frame 6 and horizontally. The forming platform 1 is rotatably mounted within the overall frame 6 via a rotary drive mechanism 2, positioned between the two Y-axis motion structures 511 and arranged horizontally perpendicular to the Y-axis. The two ends of the X-axis motion structure 512 are connected to the sliding seats of the two sets of Y-axis motion structures 511, thereby enabling the X-axis motion structure 512 to translate along the Y-axis. The extrusion unit 3 is mounted on the sliding seat of the X-axis motion structure 512 and moves along the X-axis with the X-axis motion structure 512, thereby driving the extrusion unit 3 to complete two-dimensional movement in the XY plane.

[0027] Please see Figure 1 , Figure 2 and Figure 4 In one possible embodiment, the subtractive motion mechanism 52 consists of a radial motion structure 521 and a lateral motion structure 522. The radial motion structure 521 and the transverse motion structure 522 both adopt high-precision linear modules. The radial motion structure 521 is set horizontally at the height of the middle of the overall frame 6, and its motion direction is parallel to the motion direction of the X-axis motion structure 512. The transverse motion structure 522 is set horizontally, and its motion direction is perpendicular to the radial motion structure 521 and parallel to the motion direction of the Y-axis motion structure 511. The transverse motion structure 522 is connected to the sliding seat of the radial motion structure 521, so that the transverse motion structure 522 can move radially with the radial motion structure 521. The subtractive material unit 4 is installed on the sliding seat of the transverse motion structure 522 and can move laterally under the drive of the transverse motion structure 522. Through the cooperation of the radial motion structure 521 and the transverse motion structure 522, the subtractive material unit 4 can move in two dimensions in two vertical directions on the horizontal plane. Combined with the movement of the lifting motion mechanism 53, the printing substrate at different positions on the forming platform 1 can be precisely laser-cut.

[0028] Please see Figure 1 and Figure 2In one possible embodiment, the lifting mechanism 53 includes at least two sets of lead screw lifting structures and at least two lifting platforms. Each lead screw lifting structure consists of a lifting servo motor 531 and a drive lead screw 532. The servo motor is mounted at the bottom of the overall frame 6, and its output shaft is connected to one end of the drive lead screw 532 via a coupling. The drive lead screw 532 is vertically positioned, and its other end is rotatably mounted on the upper part of the overall frame 6 via a bearing seat. The lifting platform is fixedly connected to a nut seat, and the nut seat is threadedly connected to the drive lead screw 532. At least two sets of lead screw lifting structures are respectively arranged on both sides of the forming platform 1, with their lifting drive ends connected to the corresponding lifting platforms. At least two lifting platforms are connected to the forming platform 1 via a rotary drive mechanism 2, used to drive the lifting platforms to move vertically under the synchronous drive of the lead screw lifting structures, thereby achieving stable adjustment of the forming platform 1 in the height direction.

[0029] Specifically, in this embodiment, the lifting mechanism 53 consists of four sets of lead screw lifting structures, symmetrically distributed at the four corners of the forming platform 1. Each set of lead screw lifting structures also includes an optical shaft 533 arranged in parallel on one side of the drive lead screw 532. The two ends of the optical shaft 533 are fixedly connected to the overall frame 6, and the lifting platform slides with the optical shaft 533 through linear bearings. Large-sized forming models are heavy; the symmetrical distribution design of the four sets of lead screw lifting structures ensures that the forming platform 1 is subjected to uniform force during lifting, effectively avoiding platform tilting or swaying caused by single-point support or asymmetrical support. The cooperation between the optical shaft 533 and the linear bearings further improves the straightness and stability of the lifting platform's movement, reduces frictional resistance during lifting, and ensures high-precision positioning of the forming platform 1 during height adjustment. Simultaneously, the lifting servo motors 531 in each set of lead screw lifting structures are synchronously controlled by the same controller, ensuring that the four lifting platforms maintain consistent height during lifting. The rotary drive mechanism 2 is fixedly installed on the four lifting platforms, with its output axis extending upwards and fixedly connected to the center of the bottom surface of the forming platform 1.

[0030] Of course, in other possible embodiments, the specific structural form of the three-dimensional linkage mechanism 5 is not limited to this, and other combinations can also be adopted. For example, the three-dimensional linkage mechanism 5 can be designed to drive only the extrusion unit 3 and the subtractive material unit 4 to perform three-dimensional movement, while the forming platform 1 remains fixed. The printing and processing operations are completed by the movement of the extrusion unit 3 and the subtractive material unit 4 in space. Alternatively, the three-dimensional linkage mechanism 5 can be connected separately to the forming platform 1 to drive the forming platform 1 to move in three-dimensional space, while the extrusion unit 3 and the subtractive material unit 4 are fixedly set. The movement of the forming platform 1 is used to achieve the position matching of material accumulation and laser processing.

[0031] To improve the stability of the molding platform 1 during rotation, please refer to... Figures 1 to 3In some possible embodiments, the rotary drive mechanism 2 includes a platform support frame 22 and a rotary drive component 21; the platform support frame 22 has multiple support portions extending radially along the forming platform 1. Preferably, in this embodiment, the platform support frame 22 adopts a four-corner support design, with its four support portions arranged in a circular array with the central axis of the forming platform 1 as a reference. The ends near the central axis of the forming platform 1 are connected to each other, and each support portion extends radially along the forming platform 1, with one side fixedly connected to the forming platform 1. The rotary drive component 21 is an electric rotary table 211, which is mounted on a platform support rod 23. Both ends of the platform support rod 23 are fixedly connected to two lifting platforms, respectively. The stator of the electric rotary table 211 is rigidly connected to the platform support rod 23, and the rotor is collinear with the central axis of the forming platform 1. It is fixedly connected to the center of the platform support frame 22 via a coupling, thereby driving the platform support frame 22 to rotate the forming platform 1 around its own central axis, achieving continuous and stable 360-degree rotation of the forming platform 1. The four-corner support design of the platform support frame 22 can evenly distribute the weight of the molding platform 1 to multiple support parts, which can further improve the rigidity and stability of the molding platform 1 and prevent deformation when rotating at high speed or bearing a heavy printing substrate.

[0032] Of course, in other possible embodiments, the specific structural form of the rotary drive mechanism 2 is not limited to this. Depending on the actual application scenario, a DD direct drive motor can be used to directly drive the molding platform 1 to rotate, or power can be transmitted through indirect transmission methods such as gear transmission and belt transmission.

[0033] For information on additive extrusion molding, please refer to [link / reference]. Figure 1 and Figure 5 In some possible embodiments, the extrusion unit 3 includes an extrusion nozzle 33, an extrusion drive assembly, and an extrusion cooling fan 34. The extrusion drive assembly includes an extrusion single screw module 32 and an extrusion servo motor 31. The extrusion servo motor 31 can provide high torque and achieve non-stepping rotation, thereby improving the extrusion accuracy of polymer materials and improving molding accuracy. The extrusion single screw module 32 can achieve a high-flow extrusion effect and can quickly extrude polymer materials from the extrusion nozzle 33. Specifically, the extrusion nozzle 33 is set corresponding to the molding platform 1, and its interior forms a flow channel for conveying printing material; the feeding end of the extrusion single screw module 32 is connected to an external feeding mechanism, and the discharge end is connected to the flow channel inlet of the extrusion nozzle 33; the output shaft of the extrusion servo motor 31 is connected to the screw drive of the single screw module, and is used to drive the screw to rotate to push the printing material along the flow channel to the extrusion end; the extrusion cooling fan 34 is located on the outside of the extrusion nozzle 33, and is fixedly installed outside the extrusion single screw module 32, with the air outlet facing the extrusion end of the extrusion nozzle 33, which can quickly cool the polymer material extruded by the extrusion nozzle 33, reduce flow, and improve molding quality.

[0034] Please see Figure 1 , Figure 2 and Figure 4 In order to achieve precise control of subtractive laser processing, in some possible embodiments, the subtractive unit 4 includes a laser 41, a focusing head 42 and a reflection component; the focusing head 42 is mounted on a sliding seat of the transverse motion structure 522, with its laser emitting end facing the forming platform 1, and its interior is provided with a focusing lens group for converging the laser beam; the high-pressure laser 4152, which is cooled by water, is relatively heavy and is placed at the lower end of the back of the overall frame 6, which is stable and safe, and is fixedly connected to the overall frame 6 through a support plate 47. The reflective assembly includes four reflective modules, which, for ease of explanation, are defined as the first reflective device 43, the second reflective device 44, the third reflective device 45, and the fourth reflective device 46. These four modules are sequentially positioned along the optical path between the laser 41 and the focusing head 42. The first reflective device 43 is installed at the light outlet of the laser 41 to deflect the original laser beam emitted by the laser 41 by 90 degrees, changing its direction from horizontal to vertical upward propagation. The second reflective device 44 and the third reflective device 45 are both installed in the middle of the back of the overall frame 6. The second reflective device 44 is located above the first reflective device 43 and is used to receive light emitted from the first reflective device 43. The vertically upward laser beam, after being redirected, undergoes another 90-degree turn. The third reflecting device 45 is at the same horizontal height as the second reflecting device 44, and its reflection direction is perpendicular to the second reflecting device 44. It is used to redirect the horizontally propagating laser beam by another 90 degrees, allowing the laser beam to propagate horizontally into the interior of the overall frame 6. The fourth reflecting device 46 is located at the incident end of the focusing head 42 and fixed on the fixed guide rail of the transverse motion structure 522. It is used to receive the laser beam redirected by the third reflecting device 45 and adjust the laser beam to be horizontally incident into the interior of the focusing head 42 through the reflecting lens. After being focused by the focusing lens group, a high-energy-density laser spot is formed, which precisely acts on the surface of the printing substrate. Among them, the exit end of the third reflecting device 45 is parallel to the movement direction of the radial motion structure 521. When the fourth reflecting device 46 moves radially with the radial motion structure 521, the optical path between it and the third reflecting device 45 always remains on the same straight line, effectively avoiding optical path deviation or energy loss caused by the movement of the subtractive unit 4.

[0035] Of course, in other possible embodiments, the specific structural forms of the extrusion unit 3 and the subtractive manufacturing unit 4 are not limited to this. For example, the extrusion unit 3 can select a twin-screw extrusion module according to the characteristics of the printing material to improve the uniformity of material mixing, or add a heating temperature gradient control system to accurately adjust the melting state of different materials; the subtractive manufacturing unit 4 can also use a fiber laser 41 in conjunction with a galvanometer scanning system to achieve higher speed laser processing, or integrate a real-time laser power monitoring module to ensure the stability of processing energy through feedback adjustment.

[0036] Furthermore, the equipment also includes an operation screen 7, which is mounted on the overall frame 6, allowing operators to intuitively set equipment parameters, plan processing paths, and monitor in real time. The operation screen 7 has a built-in industrial-grade embedded system that can communicate with the equipment's control system in real time via a high-speed data bus. It can dynamically display the position coordinates of the forming platform 1, the movement status of the extrusion unit 3 and the subtractive processing unit 4, laser power, printing temperature, and other key processing parameters. It also has functions such as processing process simulation preview, historical processing data query, and fault alarm prompts.

[0037] Secondly, embodiments of this application also provide a 3D printing additive-subtractive composite molding method, including a 3D printing additive-subtractive composite manufacturing apparatus as described in any of the above embodiments, the method comprising: S1: Separate the solid 3D printing model without holes from the original 3D model, and extract the hole outline and the outer boundary outline to generate the corresponding 3D printing path and laser cutting path respectively; S2: Import the solid 3D printing model into the 3D printing additive and subtractive composite manufacturing equipment. While the rotary drive mechanism 2 drives the work platform to rotate, the extrusion unit 3 extrudes the material according to the preset printing parameters. In conjunction with the 3D linkage mechanism 5, the material is stacked layer by layer along the planned path to quickly form a solid model without holes. S3: Classify the laser subtractive cutting path into small hole path, large hole path and outer contour boundary path; set appropriate laser processing parameters for each type of path. S4: Based on the classification path and matching parameters, start the subtractive material unit 4, control the three-dimensional linkage mechanism 5 to drive the subtractive material unit 4, so that the laser focusing head 42 moves along the surface contour of the solid blank; perform laser cutting on the holes and contours on the solid model, and finally obtain the finished structural product.

[0038] In terms of the forming method, by pre-separating the solid model and the hole structure, and adopting a step-by-step process of additive manufacturing followed by subtractive manufacturing, the frequency of alternation between additive and subtractive manufacturing processes is reduced. After the solid blank is formed as a whole, concentrated laser processing is performed based on the classified holes and contour paths. This not only ensures the material stacking efficiency, but also optimizes the circular scanning accuracy of small holes and the cutting surface quality of large contours through differentiated laser parameter settings, effectively solving the problem that it is difficult to balance the forming efficiency and accuracy of polymer materials in the existing technology.

[0039] In some possible embodiments, during the laser cutting process: for small hole paths, the laser focus is controlled to scan and cut along a circular trajectory with the center point of the hole as the center; for large hole paths and outer contour boundary paths, the laser focus is controlled to be offset along the normal direction of each discrete point on the contour to form a cutting trajectory equidistant from the original contour.

[0040] Further, please refer to Figures 1 to 5 This solution also provides a specific implementation method to explain in detail steps S1 to S4 above. The specific details are as follows: Step 1: Separate the solid 3D printing model (without holes) from the original 3D model, and extract the hole contours and outer boundary contours to generate corresponding 3D printing paths and laser cutting paths. The scanned positive mold is processed into a negative mold without holes. Then, based on the patient's characteristics, the boundaries and holes are drawn on the negative mold. The negative mold can be saved as a printable model, and the 3D printing path is formed by slicing, while the boundaries and holes are the laser cutting paths.

[0041] Step 2: Import the solid 3D printing model into the 3D printing additive and subtractive composite manufacturing equipment. Based on the model characteristics processed by S1, start the extrusion unit 3 and the Y-axis motion structure 511 and X-axis motion structure 512 connected to the extrusion unit 3. At the same time, start the rotary drive mechanism 2 and the lifting motion mechanism 53 connected to the forming platform 1, and adopt appropriate extrusion ratio, extrusion temperature and extrusion speed, etc.

[0042] Through the coordinated action of the X-axis motion structure 512 and the Y-axis motion structure 511, the extrusion unit 3 is driven to move precisely in the XY plane according to the preset 3D printing path. At the same time, the lifting motion mechanism 53 drives the forming platform 1 to gradually descend in the vertical direction according to the printing layer thickness requirements, ensuring that each layer of printing material can be evenly accumulated on the previous layer. The rotation drive mechanism 2 drives the forming platform 1 to rotate in a timely manner according to the complex structural requirements of the model, so that the extrusion nozzle 33 can fill the complex areas such as the sides and slopes of the model with material from different angles.

[0043] S3. Classify the holes on the model into small holes, large holes, and boundary paths. Use different laser position, attitude, speed, and power parameters for each path to improve cutting efficiency and quality. Different laser paths are used for different paths. Due to the limited focusing distance of the focusing head 42, small holes are cut using a centering method, while large holes and boundaries are cut radially to avoid collisions between the focusing head 42 and the model. Small holes are circular holes with a diameter of 10mm or less. During the cutting process, the laser power needs to be controlled within the range of 15-25W, and the scanning speed needs to be set to 300-500mm / s. The material is removed layer by layer through multiple scans of the circular trajectory to ensure the smoothness of the inner wall of the hole. Large holes refer to circular or irregular holes with a diameter greater than 10mm. The outer contour boundary is the outer perimeter edge of the model. For these two types of paths, the laser power is adjusted to 30-45W, the cutting speed is reduced to 150-250mm / s, and the laser focus is offset by 0.1-0.3mm along the contour normal direction to compensate for the heat-affected zone during the cutting process and ensure the accuracy of the contour dimensions.

[0044] S4. Based on the classification path and matching parameters, the subtractive processing unit 4 and its connected radial motion structure 521 and lateral motion structure 522 are activated. Simultaneously, the rotary drive mechanism 2 and lifting motion mechanism 53 connected to the forming platform 1 are activated. Through the coordinated drive of the radial motion structure 521 and lateral motion structure 522, the laser focusing head 42 of the subtractive processing unit 4 is precisely moved two-dimensionally on the horizontal plane of the forming platform 1. Meanwhile, the lifting motion mechanism 53 adaptively adjusts the forming platform 1 in the vertical direction according to the height requirements of laser cutting. The rotary drive mechanism 2 drives the forming platform 1 to perform necessary rotational movements according to the direction of the cutting path, ensuring that the laser focusing head 42 always acts on the area to be cut of the solid blank at the optimal angle and position. During the cutting process, the laser focusing head 42 performs circular scanning cutting on small holes and equidistant trajectory cutting with normal offset on large holes and outer contour boundaries according to the preset classification path and matching parameters. Through the close coordination between the three-dimensional linkage mechanism 5 and the forming platform 1, the laser focusing head 42 moves along the surface contour of the solid blank; the holes and contours on the solid model are laser-cut to finally obtain the finished structural product.

[0045] Because the cutting surface is an irregular surface in space, and there are problems such as the cooling and shrinkage of polymer materials and the inconsistent center points of the model, the laser cutting process uses the focusing head 42 with automatic distance adjustment in conjunction with the cutting path in S3 to cut the model with high precision and efficiency, achieving the effect of material reduction.

[0046] The 3D printing additive and subtractive composite manufacturing equipment and molding method provided by this invention, by setting up a rotatable molding platform 1, and cooperating with the three-dimensional linkage mechanism 5 to drive the extrusion unit 3 and the non-contact laser subtractive unit 4 to work together, after the overall additive deposition of the solid model is completed, the subtractive unit 4 is used to perform precise laser cutting on the holes and outer contours, avoiding the high temperature damage of traditional milling, and reducing the number of process changes. It effectively solves the problems in the prior art that the high temperature generated by contact milling during the subtractive processing of polymer materials in 3D printing easily affects the material properties and the low molding efficiency caused by frequent process changes. It significantly improves the molding accuracy and production efficiency of complex structural parts such as medical assistive devices.

[0047] In the description of this application, it should be noted that the terms "upper" and "lower," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0048] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0049] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A 3D printing additive-subtractive composite manufacturing equipment, characterized in that, include: The molding platform is used to support and fix the printing substrate; A rotary drive mechanism, the output end of which is connected to the forming platform, is used to drive the forming platform to rotate about a central axis perpendicular to its supporting plane; An extrusion unit is located above the forming platform and has an extrusion end capable of directionally extruding molten or semi-molten printing material; The subtractive material unit is located above or to the side of the forming platform, with its laser emission end facing the forming platform, and is used to selectively laser cut, mill, or engrave the printed substrate. as well as A three-dimensional linkage mechanism is connected to at least one of the forming platform, extrusion unit, and subtractive processing unit, and is used to drive the forming platform, extrusion unit, and subtractive processing laser device to perform multi-degree-of-freedom relative motion in three-dimensional space.

2. The 3D printing additive-subtractive composite manufacturing equipment according to claim 1, characterized in that, The three-dimensional linkage mechanism includes an additive motion mechanism, a subtractive motion mechanism, and a lifting motion mechanism; The output end of the additive motion mechanism is connected to the extrusion unit and is used to drive the extrusion unit to perform translational motion in the plane; The output end of the subtractive motion mechanism is connected to the subtractive unit and is used to drive the subtractive unit to perform translational motion in the plane; The output end of the lifting mechanism is connected to the forming platform, and is used to drive the forming platform to move up and down in a direction perpendicular to its supporting plane.

3. The 3D printing additive-subtractive composite manufacturing equipment according to claim 2, characterized in that, The additive motion mechanism includes a Y-axis motion structure and an X-axis motion structure; The Y-axis motion structure is arranged in the horizontal direction, and its moving end is connected to the X-axis motion structure to drive the X-axis motion structure to translate along the Y-axis direction. The X-axis motion structure is arranged in a horizontal direction perpendicular to the Y-axis, and its moving end is connected to the extrusion unit to drive the extrusion unit to translate along the X-axis direction.

4. The 3D printing additive-subtractive composite manufacturing equipment according to claim 2, characterized in that, The subtractive motion mechanism includes a radial motion structure and a lateral motion structure; The radial motion structure is arranged in the horizontal direction, and its moving end is connected to the transverse motion structure to drive the transverse motion structure to translate in the radial direction. The lateral motion structure is arranged in a horizontal direction perpendicular to the radial direction, and its moving end is connected to the subtractive material unit to drive the subtractive material unit to translate in the lateral direction.

5. The 3D printing additive-subtractive composite manufacturing equipment according to claim 2, characterized in that, The lifting mechanism includes at least two sets of lead screw lifting structures and at least two lifting platforms; At least two sets of lead screw lifting structures are respectively arranged on both sides of the forming platform, and their lifting drive ends are connected to the corresponding lifting platforms; At least two of the lifting platforms are connected to the forming platform to drive the lifting platforms to move vertically under the synchronous drive of the screw lifting structure.

6. The 3D printing additive-subtractive composite manufacturing equipment according to claim 1, characterized in that, The rotary drive mechanism includes a platform support frame and a rotary drive component; The platform support frame has multiple support portions extending radially along the molding platform, and each of the support portions is arranged in a ring array with the central axis of the molding platform as a reference. The rotary drive is connected to the platform support frame, and its output shaft is collinear with the central axis of the forming platform, used to drive the platform support frame to rotate the forming platform around the central axis.

7. The 3D printing additive-subtractive composite manufacturing equipment according to claim 1, characterized in that, The extrusion unit includes an extrusion nozzle, an extrusion drive assembly, and an extrusion cooling fan; The extrusion nozzle is configured to correspond to the molding platform, and its interior forms a flow channel for conveying printing material. The extrusion drive assembly is connected to the flow channel of the extrusion nozzle and is used to push the printing material to the extrusion nozzle at a preset pressure and speed. The extrusion cooling fan is located on the side of the extrusion nozzle, with its air outlet facing the extrusion end of the extrusion nozzle, and is used to cool and shape the extruded printing material.

8. The 3D printing additive-subtractive composite manufacturing equipment according to claim 1, characterized in that, The subtractive material unit includes a focusing head, a reflective assembly, and a laser; The laser emitting end of the focusing head is positioned directly opposite the forming platform, and its interior is equipped with a focusing lens group for converging the laser beam. The reflection component includes at least two reflection modules, which are sequentially arranged on the optical path between the laser and the focusing head to change the laser transmission direction of the laser and guide the laser beam to the focusing head.

9. A 3D printing method for additive-subtractive composite molding, characterized in that, Including the 3D printing additive-subtractive composite manufacturing equipment as described in any one of claims 1-8, the method includes: Separate the solid 3D printing model without holes from the original 3D model, and extract the hole outline and the outer boundary outline to generate the corresponding 3D printing path and laser cutting path respectively. The solid 3D printed model is imported into the 3D printing additive and subtractive composite manufacturing equipment. While the rotary drive mechanism drives the work platform to rotate, the extrusion unit extrudes the material according to the preset printing parameters. In conjunction with the 3D linkage mechanism, the material is stacked layer by layer along the planned path to quickly form a solid model without holes. The laser subtractive cutting paths are classified into small hole paths, large hole paths, and outer contour boundary paths; and laser processing parameters are set to match the different types of paths. Based on the classification path and matching parameters, the subtractive material unit is activated, and the three-dimensional linkage mechanism is controlled to drive the subtractive material unit, so that the laser focusing head moves along the surface contour of the solid blank; the holes and contours on the solid model are laser-cut to finally obtain the finished structural product.

10. The 3D printing additive-subtractive composite molding method according to claim 9, characterized in that, During laser cutting: For the path of the small hole, the laser focus is controlled to scan and cut along a circular trajectory with the center point of the hole as the center. For the large hole path and the outer contour boundary path, the laser focus is controlled to be offset along the normal direction of each discrete point on the contour to form a cutting trajectory equidistant from the original contour.

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