3D printing preheating device

Abstract

The invention relates to the technical field of 3D printing, and discloses a 3D printing preheating device which comprises a nozzle, a preheating pipe is connected to the nozzle, a plurality of heating pipes arranged at equal intervals are arranged in an interlayer of the pipe wall of the preheating pipe, a pipe cover is connected to the top end of the preheating pipe, a feeding pipe is connected to the pipe cover, and a stirring assembly is connected to the pipe cover. The stirring assembly comprises a rotating rod rotationally arranged in the center of the pipe cover, multiple sets of stirring paddles are vertically arrayed on the rotating rod, a power mechanism used for driving the rotating rod to rotate at a low speed is arranged on the pipe cover, and soft scraping plates matched with the inner wall of the preheating pipe are symmetrically connected to the rotating rod. The stirring assembly is adopted, raw materials in the pipe are heated evenly, the melting quality of the raw materials is improved, meanwhile, the soft scraper can scrape the raw materials attached to the inner wall of the preheating pipe, and the condition of discharging blockage is effectively prevented.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, specifically to a 3D printing preheating device. Background Technology

[0002] 3D printing, also known as additive manufacturing, is an advanced manufacturing technology that directly transforms a digital model into a solid part by layer-by-layer accumulation of material, based on 3D CAD digital model data. Unlike traditional subtractive manufacturing and equal-material manufacturing, additive manufacturing eliminates the need for molds, tools, or fixtures. Instead, it progressively stacks points, lines, and surfaces according to a pre-defined 3D structure to form a 3D solid. This enables the rapid prototyping of complex shapes and integrated structures, significantly simplifying traditional manufacturing processes and shortening product development and production cycles. This technology integrates computer graphics processing, digital control, and new material applications, and can utilize various process paths, such as fused deposition modeling, photopolymerization, selective laser sintering, and metal powder bed melting, depending on the material type and forming principle. It enables rapid prototyping, personalized customization, small-batch production, and direct manufacturing of functional parts in fields such as aerospace, medical, automotive, mold making, and cultural and creative education, representing a crucial development direction for intelligent and green manufacturing.

[0003] For thermoplastic granules (rather than thermoplastic wires), the raw material is usually melted and then extruded through a nozzle. A preheating device is typically installed on the nozzle to preheat the raw material granules entering the hot end. However, traditional preheating structures often use straight-through heating tubes, which can lead to uneven heating of the raw material. A temperature difference exists between granules in the center of the preheating tube and those near the outer wall, resulting in unstable output. Furthermore, raw material near the tube wall tends to adhere to it, and over time, this accumulation can cause channel narrowing, affecting output.

[0004] Meanwhile, in existing 3D printing particle preheating technologies, although some devices improve the melting state of raw materials by increasing heating power or extending the preheating path, they still largely rely on heating methods within a single temperature zone, lacking segmented temperature control designs for the material conveying direction. This results in abrupt temperature changes before and after the raw material enters the melting stage, easily leading to problems such as localized overheating, agglomeration, or insufficient melting. Existing stirring structures are mostly of a single form, making it difficult to simultaneously address the different needs of initial material conveying and subsequent enhanced mixing, especially when handling raw materials with different particle sizes or thermal properties. Furthermore, traditional structures have weak control over the flow state of materials within the preheating tube, and localized material stagnation still exists, thus affecting the continuity and stability of overall output. Therefore, how to improve the uniformity of material preheating and conveying stability through the synergistic effect of multi-stage heating and differentiated stirring, while ensuring structural feasibility, has become one of the urgent technical problems to be solved in this field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the issues mentioned in the background art, such as uneven heating of raw material particles in the preheating tube and the easy adhesion of raw materials to the tube wall due to the lack of a clean structure, which affects the discharge of materials. The present invention proposes a 3D printing preheating device.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a 3D printing preheating device, including a nozzle and a preheating tube connected to the nozzle, wherein a heating tube is provided in the interlayer of the preheating tube wall, the heating tube is located in a vacuum environment and heats the powder entering the preheating tube; a stirring assembly is rotatably provided on the inner wall of the preheating tube, the stirring assembly being used to stir the powder while heating it.

[0007] Furthermore, a pipe cap is connected to the top of the preheating pipe, and a feed pipe is connected to the pipe cap.

[0008] Furthermore, the stirring assembly is rotatably mounted on the tube cover, including a rotating rod rotatably mounted at the center of the tube cover, and multiple sets of stirring paddles are vertically arrayed on the rotating rod.

[0009] Furthermore, the pipe cover is provided with a power mechanism for driving the rotating rod to rotate at low speed, and the rotating rod is symmetrically connected with soft scrapers that match the inner wall of the preheating pipe.

[0010] Furthermore, the power mechanism includes a stepper motor fixedly mounted above the pipe cover, the output end of the stepper motor is connected to a worm gear, and one end of the rotating rod extends above the pipe cover and is connected to a worm wheel that meshes with the worm gear.

[0011] Furthermore, a protective cover is provided on the top surface of the pipe cover above the power mechanism.

[0012] Furthermore, the stirring paddle is provided in two sets, and one set of stirring paddles has a three-bladed oblique paddle structure.

[0013] Furthermore, the pipe cover is threaded to the top of the preheating pipe, and the pipe cover has a groove that fits the wall of the preheating pipe, and a sealing ring is provided in the groove.

[0014] Furthermore, the outer wall of the preheating tube is connected to an insulation cover, and there is a vacuum interlayer between the insulation cover and the preheating tube, with the heating tube located in the vacuum interlayer.

[0015] Furthermore, a heat insulation sleeve is provided on the outside of the heat insulation cover.

[0016] The advantages of this invention compared to the prior art are:

[0017] 1. By setting up the stirring component, the stirring paddle on the rotating rod rotates at low speed, which can actively stir the material in the preheating tube, promote the uniformity of the raw material temperature in the tube, prevent local overcooling or overheating, ensure the consistency of the raw material melting quality, and thus improve the quality of the printed parts.

[0018] 2. At the same time, a soft scraper is connected to the rotating rod, which can gently scrape the inner wall of the preheating tube while the rod rotates, thus removing the deposits formed on the inner wall of the preheating tube in time, keeping the discharge channel unobstructed, and greatly reducing the risk of blockage.

[0019] 3. By segmenting and optimizing the internal heating and stirring structures of the preheating tube, a gradient temperature distribution is formed along the material conveying direction. Combined with stirring paddles of different structures on the rotating rod, the material is gradually transitioned from preheating to enhanced mixing. This effectively avoids the problem of uneven heating or local over-melting of the material in a short time, and significantly improves the adaptability to different types of raw materials.

[0020] 4. The segmented and spirally staggered soft scrapers not only clean the inner wall of the preheating pipe, but also provide auxiliary material conveying, reducing material retention and accumulation, and further ensuring the continuity of material output. In addition, by adjusting the speed of the stepper motor, the mixing intensity is matched with the material state, improving mixing efficiency while ensuring material quality. Overall, this further enhances the stability, adaptability, and consistency of the printing quality of the device. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a 3D printing preheating device according to the present invention.

[0022] Figure 2 yes Figure 1 A schematic diagram of the explosion structure.

[0023] Figure 3 yes Figure 2 A schematic diagram of the vertical half-section structure of the preheating pipe.

[0024] Figure 4 yes Figure 2 A schematic diagram of the connection structure between the pipe cover and the stirring assembly.

[0025] Figure 5 yes Figure 4 A magnified schematic diagram of the local A structure.

[0026] Figure 6 yes Figure 4 A schematic diagram of the internal structure of the protective shield viewed from above.

[0027] [Explanation of Labels in the Attached Image]

[0028] 1. Nozzle; 2. Preheating pipe; 3. Heating pipe; 4. Pipe cover; 5. Feed pipe; 6. Rotating rod; 7. Soft scraper; 8. Stepper motor; 9. Worm gear; 10. Worm wheel; 11. Protective cover; 12. Sealing ring; 13. Insulation cover; 14. Heat insulation sleeve; 15. Agitator. Detailed Implementation

[0029] To make the content of this invention easier to understand, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Identical components are indicated by the same reference numerals.

[0030] It should be noted that the terms “front,” “back,” “left,” “right,” “up,” and “down” used in the following description refer to the directions shown in the attached diagram, while the terms “inside” and “outside” refer to the directions toward or away from the geometric center of a specific component, respectively.

[0031] Example 1

[0032] Combined with appendix Figure 1 , Figures 3 to 5 As shown, a 3D printing preheating device includes a nozzle 1, a preheating tube 2 connected to the nozzle 1, a plurality of heating tubes 3 arranged at equal intervals in the tube wall interlayer of the preheating tube 2, a tube cap 4 connected to the top of the preheating tube 2, the tube cap 4 being threadedly connected to the top of the preheating tube 2, a groove adapted to the tube wall of the preheating tube 2 being provided in the tube cap 4, and a sealing ring 12 being provided in the groove.

[0033] In the above structure, the equidistantly arranged heating tubes 3 ensure the uniformity of temperature distribution in the vertical direction inside the preheating tube 2, avoiding temperature differences inside the preheating tube 2. At the same time, the tube cover 4 and the preheating tube 2 form a closed heating wall, effectively reducing heat evaporation. Moreover, the sealing ring 12 can fill the gap at the connection between the tube cover 4 and the preheating tube 2, ensuring the sealing of the top of the preheating tube 2 and preventing excessive heat loss and material leakage.

[0034] The threaded connection between the pipe cover 4 and the preheating pipe 2 facilitates the disassembly of the pipe cover 4, enabling regular cleaning of the interior and ensuring the stability of the subsequent material output, thus preventing material blockage.

[0035] To ensure that the raw material particles inside preheating tube 2 are heated evenly, combined with the attached... Figure 2 and Figure 4 As shown, a feed pipe 5 is connected to the pipe cover 4, and a stirring assembly is connected to the pipe cover 4. The stirring assembly includes a rotating rod 6 rotatably located at the center of the pipe cover 4. Multiple sets of stirring paddles 15 are vertically arrayed on the rotating rod 6. There are two sets of stirring paddles 15, and one set of stirring paddles 15 has a three-bladed oblique paddle structure. The pipe cover 4 is provided with a power mechanism for driving the rotating rod 6 to rotate at low speed. Soft scrapers 7 that match the inner wall of the preheating pipe 2 are symmetrically connected to the rotating rod 6.

[0036] In the above structure, the soft scraper 7 can be made of silicone, which has good flexibility and can fit tightly against the inner wall of the preheating tube 2. It can also deform with the slight unevenness of the inner wall of the preheating tube 2 to achieve effective scraping, while avoiding damage to the hard inner wall of the preheating tube 2. Moreover, silicone is resistant to high temperature and can withstand the high temperature environment inside the preheating tube 2 during the preheating process. The soft scraper 7 made of silicone has a smooth surface, and molten plastic particles are not easy to adhere to the soft scraper 7.

[0037] The inclined blade structure of the stirring blade 15 is conducive to generating axial and radial mixing effects, promoting more thorough circulation and mixing of materials in the preheating tube 2, improving heating uniformity, and the setting of multiple sets of stirring blades 15 can enhance the mixing effect.

[0038] Combined with appendix Figure 1 and Figure 6 As shown, the power mechanism includes a stepper motor 8 fixedly mounted above the tube cover 4. The output end of the stepper motor 8 is connected to a worm gear 9. One end of the rotating rod 6 extends above the tube cover 4 and is connected to a worm wheel 10 that meshes with the worm gear 9. A protective cover 11 is provided on the top surface of the tube cover 4 above the power mechanism. The protective cover 11 can protect the power mechanism mounted above the tube cover 4, so that its internal components are protected from high temperature, dust and other damage, and play a certain safety protection role.

[0039] With the above structure, the stepper motor 8 is fixed above the tube cover 4, providing a power source for precise speed control, thereby driving the worm 9 to rotate. The worm 9 meshes with the worm wheel 10. Since the worm wheel 10 and worm 9 transmission has a significant speed reduction ratio, the rotating rod 6 and the stirring paddle 15 and soft scraper 7 connected to the rotating rod 6 can rotate at low speed. The stirring paddle 15 stirs and mixes the raw materials inside the preheating tube 2, and the soft scraper 7 scrapes the inner wall of the preheating tube 2 to remove the attached molten raw materials or particle agglomerates to ensure heat conduction.

[0040] The low-speed rotation of the stirring paddle 15 can avoid excessive shearing of the raw materials while mixing them, ensuring the quality of the molten raw materials and making them heat evenly.

[0041] With the combined effects of active stirring and wall scraping, the uniformity of material heating inside the preheating tube 2 is ensured, heating efficiency is improved, thereby enhancing the stability of the subsequent 3D printing process and ultimately improving the quality of the printed parts.

[0042] Combined with appendix Figure 3As shown, the outer wall of the preheating pipe 2 is connected to an insulation cover 13. There is a vacuum interlayer between the insulation cover 13 and the preheating pipe 2. In a vacuum state, heat convection and heat conduction are extremely difficult, which has a good heat insulation effect, greatly reduces heat loss, improves heating efficiency, and reduces energy consumption. An insulation sleeve 14 is provided on the outside of the insulation cover 13. The insulation sleeve 14 is set on the outer layer of the insulation cover 13, which provides additional heat insulation protection and reduces the risk of burns to the operator.

[0043] In summary, during actual use, the powder or granular thermoplastic raw material to be processed is added into the preheating pipe 2 through the feed pipe 5. The heating pipe 3, located in the interlayer of the preheating pipe 2 wall, is activated to heat the material. At the same time, the stepper motor 8 is activated, and the rotating rod 6 is driven to rotate at low speed through the meshing transmission of the worm gear 9 and the worm wheel 10. Multiple sets of stirring paddles 15 on the rotating rod 6 continuously stir the material in the preheating pipe 2, so that the material circulates in the axial and radial directions, thereby achieving uniform heating. During the stirring process, the soft scraper 7 set on the rotating rod 6 rotates synchronously along the inner wall of the preheating pipe 2 to scrape off the material adhering to the inner wall and prevent material accumulation. After being fully preheated, the material enters the nozzle 1 from the lower end of the preheating pipe 2 and is extruded and formed. Throughout the process, the vacuum interlayer formed between the heat insulation cover 13 and the preheating pipe 2, as well as the outer heat insulation sleeve 14, work together to reduce heat loss and maintain a stable heating environment.

[0044] By installing a stirring assembly consisting of a rotating rod 6 and a stirring paddle 15 inside the preheating tube 2, the material is continuously agitated and mixed during the heating process, effectively reducing the temperature difference of the material in the radial direction of the preheating tube 2 and improving the consistency and stability of the material melting. At the same time, the soft scraper 7 set on the rotating rod 6 scrapes the inner wall of the preheating tube 2 in real time, which can prevent the material from adhering and gradually accumulating under high temperature conditions, avoiding the narrowing or even blockage of the channel, and ensuring that the material is stably extruded from the nozzle 1. In addition, the structure of the heating tube 3 set in the vacuum jacket and combined with the heat insulation cover 13 and the heat insulation sleeve 14 can effectively reduce heat loss, improve heating efficiency and reduce energy consumption, thereby further improving the overall stability of the device operation and the 3D printing molding quality.

[0045] Example 2

[0046] Based on Example 1, this example further optimizes the heating and material transport coordination method in the preheating tube 2 to improve the adaptability of powders with different particle sizes and different heat-melting characteristics in the preheating stage.

[0047] Specifically, the preheating pipe 2 is divided into a preheating section and an enhanced mixing section along the axial direction. The side closer to the feed pipe 5 is the preheating section, and the side closer to the nozzle 1 is the enhanced mixing section. The heating pipes 3 are arranged in sections within the preheating section and the enhanced mixing section, and the heating pipes 3 in each section can be independently energized and controlled so that a temperature gradient gradually increases along the material conveying direction is formed in the preheating pipe 2.

[0048] More preferably, the rotating rod 6 is equipped with differentiated structures in different sections. In the preheating section, the stirring paddle 15 on the rotating rod 6 is a propulsion type blade with a small inclination angle, which is used to initially tumble the incoming powder and slowly convey it downwards. In the enhanced mixing section, the stirring paddle 15 is a three-bladed oblique paddle structure, which is used to enhance the radial and axial mixing effect of the material, so that the material is fully and evenly heated when it is close to the molten state.

[0049] Furthermore, the soft scraper 7 is configured as a segmented structure along the length of the enhanced mixing section. Each segment of the soft scraper 7 is arranged in a spiral staggered manner relative to the rotating rod 6. Thus, during the rotation process, it can not only scrape off the deposits on the inner wall of the preheating pipe 2, but also generate a certain axial pushing effect on the material, avoiding local material retention.

[0050] Furthermore, the stepper motor 8 adopts an adjustable speed control method, which allows the rotor 6 to run at a lower speed in the preheating section and increase the speed under the corresponding working conditions in the enhanced mixing section, thereby improving the mixing efficiency while ensuring that the material is not subjected to excessive shearing.

[0051] Furthermore, the pipe cover 4 is equipped with a temperature detection element (not shown in the figure) for detecting the internal temperature of the preheating pipe 2, which is used to monitor the temperature of different areas in order to cooperate with the zonal control of the heating pipe 3 and achieve a stable preheating temperature field.

[0052] The working process of this embodiment is as follows: After the material enters the preheating pipe 2 through the feed pipe 5, it is first heated at a lower temperature in the preheating section, and slowly turned and conveyed downward under the action of the stirring paddle 15 driven by the rotating rod 6; then the material enters the enhanced mixing section, where it is fully mixed and uniformly heated under a higher temperature and stronger stirring action. At the same time, the soft scraper 7 continuously cleans the inner wall and assists the material flow. Finally, the fully preheated material is extruded from the nozzle 1.

[0053] With the above structural design, this embodiment further improves the adaptability to different types of powders compared to embodiment 1. By combining zoned heating and segmented stirring, the material is gradually heated and fully mixed during the preheating process, avoiding local over-melting or agglomeration caused by instantaneous high temperature. At the same time, the segmented soft scraper 7 cleans the inner wall while also having a conveying function, effectively preventing material retention and improving the overall conveying stability, thereby further improving the continuity of the 3D printing process and the molding quality.

[0054] In specific implementations of this invention, the contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0055] The present invention and its embodiments have been described above, and this description is not restrictive. If those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A 3D printing preheating device, characterized in that: It includes a nozzle (1) and a preheating tube (2) connected to the nozzle (1). The preheating tube (2) has a heating tube (3) in the interlayer of its wall. The heating tube (3) is located in a vacuum environment and heats the powder entering the preheating tube (2). The inner wall of the preheating tube (2) is equipped with a stirring assembly, which is used to stir the powder while heating it.

2. The 3D printing preheating device according to claim 1, characterized in that: The preheating pipe (2) is connected to a pipe cap (4) at the top, and a feed pipe (5) is connected to the pipe cap (4).

3. The 3D printing preheating device according to claim 2, characterized in that: The stirring assembly is rotatably mounted on the tube cover (4), including a rotating rod (6) rotatably mounted at the center of the tube cover (4), and a plurality of stirring paddles (15) are vertically arrayed on the rotating rod (6).

4. The 3D printing preheating device according to claim 1, characterized in that: The pipe cover (4) is provided with a power mechanism for driving the rotating rod (6) to rotate at low speed. The rotating rod (6) is symmetrically connected with soft scrapers (7) that match the inner wall of the preheating pipe (2).

5. A 3D printing preheating device according to claim 1, characterized in that: The power mechanism includes a stepper motor (8) fixedly mounted above the pipe cover (4). The output end of the stepper motor (8) is connected to a worm gear (9). One end of the rotating rod (6) extends above the pipe cover (4) and is connected to a worm wheel (10) that meshes with the worm gear (9).

6. A 3D printing preheating device according to claim 1, characterized in that: The top surface of the pipe cover (4) is covered with a protective cover (11) above the power mechanism.

7. A 3D printing preheating device according to claim 6, characterized in that: The stirring paddle (15) is provided in two sets, and one set of stirring paddle (15) is a three-bladed oblique paddle structure.

8. A 3D printing preheating device according to claim 7, characterized in that: The pipe cover (4) is threaded to the top of the preheating pipe (2), and the pipe cover (4) has a groove that fits the wall of the preheating pipe (2), and a sealing ring (12) is provided in the groove.

9. A 3D printing preheating device according to claim 8, characterized in that: The preheating tube (2) is connected to an insulation cover (13) on its outer wall. The insulation cover (13) and the preheating tube (2) are separated by a vacuum interlayer. The heating tube (3) is located in the vacuum interlayer.

10. A 3D printing preheating device according to claim 9, characterized in that: The heat insulation cover (13) is fitted with a heat insulation sleeve (14) on the outside.

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