3D printing nozzle feeding device for PVC plastic and 3D printing nozzle

Abstract

The invention discloses a 3D printing spray head feeding device for PVC plastics and a 3D printing spray head, and relates to the technical field of 3D printing spray heads. The 3D printing spray head feeding device for PVC plastics comprises a feeding pipeline, a limiting block is arranged on the outer portion of the feeding pipeline in an attached mode, a heat dissipation pipe is in threaded connection with the outer surface of the bottom end of the limiting block, and a throat pipe is arranged in the heat dissipation pipe in an attached mode; a heating block is detachably and fixedly mounted on the outer surface of the bottom end of the throat pipe, a nozzle is in threaded connection with the inner surface of the bottom end of the throat pipe, and the cleaning assembly is arranged in the feeding pipeline; through the arrangement of the dredging rod, the spiral conveying channel and the supporting spring, the interior of the nozzle is cleaned after 3D printing is completed, then the nozzle is prevented from being blocked, the dredging rod can eject impurities solidified in the nozzle open, and crystals or carbonized residues can be decomposed through shearing force through the rotating motion of the spiral conveying channel; and the spiral structure rotates synchronously when pushing the residues, so that small particles attached to the inner wall of the channel can be taken away, and the risk of secondary accumulation is reduced.

Description

Technical Field

[0001] This invention relates to the field of 3D printing nozzle technology, specifically to a 3D printing nozzle feeding device and a 3D printing nozzle for PVC plastic. Background Technology

[0002] 3D printing (3DP), also known as additive manufacturing technology, is a technology that manufactures solid parts by adding materials layer by layer based on three-dimensional CAD data.

[0003] Existing technology uses PVC plastic melted by a nozzle to be extruded through the nozzle to complete the 3D printing of products. However, in actual use, the material remaining in the nozzle after the last printing gradually loses its fluidity and hardens during natural cooling, forming dense solid blocks. These blocks can directly block the small apertures of the nozzle, causing mechanical resistance when new consumables are extruded. Long-term accumulated residual hard blocks may even scratch the inner wall of the nozzle or react chemically with the newly entered high-temperature material to generate carbonized residues that are difficult to remove, further aggravating the risk of blockage.

[0004] Furthermore, an existing authorized patent with publication number CN117400533A discloses a 3D printing nozzle feeding device and a 3D printing nozzle. This device utilizes an "anti-clogging part, which includes an anti-clogging rod slidably connected to the interior of a heating block and adapted to an extrusion orifice; and a traction part, which is mounted on one end of a base and adapted to a throat tube, and the traction part guides the printing filament; wherein, at room temperature, the anti-clogging rod penetrates the interior of the extrusion orifice, and during operation, the anti-clogging rod and the extrusion orifice are disengaged." This achieves the goal of "sensing the temperature inside the heating block through a driving element; after the printing operation is completed, the temperature inside the heating block gradually decreases; when the temperature is lower than the abnormal temperature of the driving element, the driving element drives the driving rod and the anti-clogging rod to operate, causing the anti-clogging rod to penetrate the interior of the extrusion orifice and remove the residual molten filament inside the extrusion orifice."

[0005] However, in practice, the anti-clogging rod operates through a drive element. When the electronic components are used inside the heated nozzle, their parameters drift due to the high temperature. Furthermore, temperature fluctuations causing changes in the material's microstructure (such as enlarged solder joint pores) increase contact resistance, potentially damaging the drive element.

[0006] To address this issue, we propose a 3D printing nozzle feeding device and a 3D printing nozzle for PVC plastics, thus resolving the aforementioned problems. Summary of the Invention

[0007] Technical problems to be solved In view of this, and in view of the shortcomings of the prior art, the present invention provides a 3D printing nozzle feeding device and a 3D printing nozzle for PVC plastics, so as to solve the problems mentioned in the background art.

[0008] Technical solution To achieve the above objectives, the present invention provides the following technical solution: a 3D printing nozzle feeding device for PVC plastic, including a feeding pipe, a limiting block is attached to the outside of the feeding pipe, a heat dissipation pipe is threadedly connected to the outer surface of the bottom end of the limiting block, a throat is attached to the inside of the heat dissipation pipe, a heating block is detachably fixedly installed on the outer surface of the bottom end of the throat, a nozzle is threadedly connected to the inner surface of the bottom end of the throat, and a cleaning component is also provided inside the feeding pipe. The cleaning assembly includes a flow pipe threaded to the inner wall of the bottom end of the throat tube. A positioning component is fixedly installed between the inner walls of the bottom end of the flow pipe. A dredging rod is set inside the positioning component. A spiral conveying channel is fixedly connected to the outer surface of the top end of the dredging rod in a centrally symmetrical manner. A guide rod is fixedly connected to the inner wall of one side of the positioning component. A spiral groove is opened on the outer surface of the dredging rod. A support spring is sleeved on the outer surface of the dredging rod. A protective plate is fixedly connected to the outer surface of the dredging rod.

[0009] Preferably, the limiting block, throat, heating block and nozzle are arranged sequentially from top to bottom along the outer wall of the feeding pipe, and the inside of the top of the heat dissipation pipe is engaged between the limiting block and the throat.

[0010] Preferably, one end of the feeding pipe extends into the interior of the throat, and the end of the feeding pipe inside the throat abuts against the surface of the top of the flow pipe. The feeding pipe, the flow pipe, and the nozzle interior are arranged in sequence along the vertical direction and are interconnected to form a conveying channel for 3D printing material. An acceleration channel is opened inside the flow pipe, which consists of a top frustum-shaped channel and a bottom trapezoidal channel. The bottom surface of the flow pipe abuts against the top surface of the nozzle.

[0011] Preferably, the diameter of the top frustum channel in the acceleration channel gradually decreases from top to bottom, and the inner wall of the top frustum channel along the vertical direction is set as equidistant elliptical arc surfaces, with the major axis of the inner diameter of the elliptical arc surfaces decreasing sequentially. The inner diameter of the bottom tier channel gradually increases along the vertical direction, and the inner diameter of the bottom of the bottom tier channel is equal to the inner diameter of the top frustum channel.

[0012] Preferably, the top of the unblocking rod is located inside the acceleration channel, and the spiral conveying channel is located inside the bottom of the top frustum channel. The size of the spiral conveying channel is adapted to the inner diameter of the bottom of the top frustum channel in the acceleration channel of the flow pipe, and the bottom of the unblocking rod extends into the interior of the nozzle.

[0013] Preferably, the flow channel is located inside the bottom frustum channel, the guide rod is slidably connected to the inside of the spiral groove, the support spring is located inside the protective plate, and the top end of the support spring abuts against the inner wall of the top of the protective plate, the bottom end of the support spring abuts against the top surface of the flow channel, and the protective plate is slidably connected to the inside of the top of the flow channel.

[0014] Preferably, it also includes auxiliary components disposed inside the heating block; The auxiliary components include a receiving cavity opened inside the bottom end of the heating block, a positioning ring slidably connected inside the receiving cavity, a limit spring fitted to the top surface of the positioning ring, a snap-fit ​​block fixedly connected to the bottom surface of the positioning ring, a piston sealing ring fitted to the outer side of the positioning ring, and a snap-fit ​​rod fixedly installed on the upper surface of the nozzle.

[0015] Preferably, the inner top wall of the positioning ring and the side wall of the receiving cavity form a contraction cavity, the limiting spring is disposed inside the contraction cavity, the top end of the limiting spring is in contact with the top cavity wall of the receiving cavity, the outer side wall of the positioning ring and the receiving cavity form a heat preservation cavity, and the outer wall of the snap-fit ​​block and the side cavity walls of the receiving cavity form a snap-fit ​​cavity.

[0016] Preferably, the snap-fit ​​rod is arranged symmetrically along the central axis of the snap-fit ​​block, and the top of the snap-fit ​​rod is snapped and fixed to the snap-fit ​​block, and the top outer wall of the nozzle seals the snap-fit ​​cavity.

[0017] A 3D printing nozzle includes a 3D printing nozzle feeding device for PVC plastic.

[0018] Compared with the prior art, the present invention provides a 3D printing nozzle feeding device and a 3D printing nozzle for PVC plastics, which have the following beneficial effects: By using a cleaning rod, a spiral conveying channel, and a support spring, the inside of the nozzle is cleaned after 3D printing, thus preventing nozzle blockage. The cleaning rod can push open solidified impurities inside the nozzle, while the rotation of the spiral conveying channel can decompose crystals or carbonized residues through shearing force. Furthermore, the spiral structure rotates synchronously when pushing residues, which can carry away tiny particles attached to the inner wall of the channel, reducing the risk of secondary accumulation.

[0019] By setting up flow channels, the flow rate of molten filament is accelerated. Accelerated filament flow can shorten the printing time of a single layer, which is especially suitable for large-size models or mass production scenarios. It significantly improves the overall printing speed. Accelerated flow helps to reduce the residence time of molten material in the nozzle, reducing the risk of degradation caused by prolonged heating, thereby improving the consistency of extruded material and molding quality.

[0020] In the acceleration channel, the diameter of the top frustum-shaped channel gradually decreases, which can compress the molten material to form a more concentrated flow core and reduce the probability of edge vortices. The equidistant distribution of the elliptical arc surface may further guide the laminar flow state and avoid local pressure fluctuations caused by sudden contraction. The design of the bottom trapezoidal channel with gradually increasing inner diameter may expand the flow cross-sectional area while maintaining the pressure gradient, thereby achieving secondary acceleration while ensuring continuous material supply. This staged variable diameter structure can control the flow velocity curve more accurately than a single conical pipe.

[0021] The rotation of the spiral conveyor channel generates shear force, promoting uniform heating and stabilization of the molten state of the material. It is especially suitable for the initial transport of high-viscosity or infilled composite materials, avoiding material delamination during the initial 3D printing process. The rotation of the spiral conveyor channel also helps to scrape away residues from the inner wall of the flow channel, preventing blockage caused by long-term material accumulation. At the same time, the elliptical cross-section design reduces dead zones.

[0022] The locking rod and locking block work together to form a locking structure. After the nozzle is threadedly connected, the installation between the nozzle and the throat is further completed, preventing the nozzle from becoming loose after long-term use.

[0023] By simultaneously setting up an insulation cavity between the outer wall of the positioning ring and the accommodating cavity, a snap-fit ​​cavity between the outer wall of the snap-fit ​​block and the two side cavities of the accommodating cavity, and a nozzle that seals the accommodating cavity, the nozzle is kept warm when it sprays consumables.

[0024] The heat insulation cavity forms a heat insulation layer through the gap between the outer wall of the positioning ring and the accommodating cavity, which reduces heat loss in the nozzle area and avoids changes in material viscosity caused by temperature fluctuations, thereby ensuring extrusion smoothness and molding accuracy.

[0025] The nozzle's sealing effect on the accommodating cavity, combined with the surrounding layout of the insulation cavity, forms a double sealing system to maintain stability and further ensure the robustness of the nozzle's threaded connection.

[0026] The layered cavity structure (with the insulation cavity on the outside and the snap-fit ​​cavity on the inside) disperses thermal expansion stress, avoids component deformation caused by repeated heating and cooling, and extends the service life of the nozzle and throat. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall appearance and structure of the present invention; Figure 2 For the present invention Figure 1 Another perspective structural diagram; Figure 3 This is a schematic planar cross-sectional view of the internal structure of the limiting block of the present invention; Figure 4This is a schematic diagram of the internal cross-sectional structure of the throat tube of the present invention; Figure 5 This is a schematic planar cross-sectional view of the internal structure of the throat tube of the present invention; Figure 6 This is a schematic diagram of the internal cross-sectional structure of the flow channel of the present invention; Figure 7 This is a schematic planar cross-sectional view of the nozzle of the present invention; Figure 8 For the present invention Figure 7 Enlarged schematic diagram of the structure at point A in the middle; Figure 9 This is a schematic diagram of the connection relationship at the unblocking rod of the present invention; Figure 10 This is a schematic diagram showing the positional relationship of the heating block in this invention; Figure 11 For the present invention Figure 10 Enlarged schematic diagram of the structure at point B.

[0028] In the diagram: 11. Feeding pipe; 12. Limiting block; 13. Heat dissipation pipe; 14. Throat; 15. Heating block; 16. Nozzle; 21. Flow channel; 22. Positioning component; 23. Unblocking rod; 24. Spiral conveyor channel; 25. Guide rod; 26. Spiral groove; 27. Support spring; 28. Protective plate; 31. Receiving cavity; 32. Positioning ring; 33. Limiting spring; 34. Snap-fit ​​block; 35. Piston seal ring; 36. Snap-fit ​​rod. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1 Please see Figures 1 to 11 A 3D printing nozzle feeding device for PVC plastic includes a feeding pipe 11, a limiting block 12 is attached to the outside of the feeding pipe 11, a heat dissipation pipe 13 is threadedly connected to the outer surface of the bottom end of the limiting block 12, a throat 14 is attached to the inside of the heat dissipation pipe 13, a heating block 15 is detachably fixedly installed on the outer surface of the bottom end of the throat 14, and a nozzle 16 is threadedly connected to the inner surface of the bottom end of the throat 14. It also includes a cleaning component disposed inside the feeding pipe 11. The cleaning assembly includes a flow pipe 21 threaded to the inner wall of the bottom end of the throat 14. A positioning element 22 is fixedly installed between the inner walls of the bottom end of the flow pipe 21. A dredging rod 23 is provided inside the positioning element 22. A spiral conveying channel 24 is fixedly connected to the outer surface of the top end of the dredging rod 23 in a centrally symmetrical manner. A guide rod 25 is fixedly connected to the inner wall of one side of the positioning element 22. A spiral groove 26 is opened on the outer surface of the dredging rod 23. A support spring 27 is sleeved on the outer surface of the dredging rod 23. A protective plate 28 is fixedly connected to the outer surface of the dredging rod 23.

[0031] The limiting block 12, the throat 14, the heating block 15 and the nozzle 16 are arranged sequentially from top to bottom along the outer wall of the feeding pipe 11, and the top of the heat dissipation pipe 13 is internally engaged between the limiting block 12 and the throat 14.

[0032] One end of the feeding pipe 11 extends into the interior of the throat 14, and the end of the feeding pipe 11 inside the throat 14 abuts against the top surface of the flow pipe 21. The feeding pipe 11, the flow pipe 21 and the nozzle 16 arranged in sequence along the vertical direction are interconnected to form a conveying channel for 3D printing materials. An acceleration channel is opened inside the flow pipe 21, which consists of a top frustum-shaped channel and a bottom trapezoidal channel. The bottom surface of the flow pipe 21 abuts against the top surface of the nozzle 16.

[0033] In the acceleration channel, the diameter of the top frustum channel gradually decreases from top to bottom, and the inner wall of the top frustum channel along the vertical direction is set as equidistant elliptical arc surfaces, with the major axis of the inner diameter of the elliptical arc surfaces decreasing sequentially. The inner diameter of the bottom truncate channel gradually increases along the vertical direction, and the inner diameter of the bottom of the bottom truncate channel is equal to the inner diameter of the top frustum channel.

[0034] The top of the unblocking rod 23 is located inside the acceleration channel, and the spiral conveying channel 24 is located inside the bottom of the top frustum channel. The size of the spiral conveying channel 24 is adapted to the bottom inner diameter of the top frustum channel in the acceleration channel of the flow pipe 21. The bottom of the unblocking rod 23 extends into the interior of the nozzle 16.

[0035] The flow channel 21 is located inside the bottom frustum channel, the guide rod 25 is slidably connected to the inside of the spiral groove 26, the support spring 27 is located inside the protective plate 28, and the top end of the support spring 27 abuts against the inner wall of the top of the protective plate 28, the bottom end of the support spring 27 abuts against the top surface of the flow channel 21, and the protective plate 28 is slidably connected to the inside of the top of the flow channel 21.

[0036] Please see Figure 5In an optional embodiment, the limiting block 12 is used to limit the position of the feeding pipe 11. The limiting block 12 cooperates with the throat 14 to limit the position of the feeding pipe 11 and the heat dissipation pipe 13. The heat dissipation pipe 13 is used to cool the consumable material after it has been melted and entered the feeding pipe 11 to a certain extent, so as to avoid the consumable material temperature being too high and difficult to be shaped after being formed and discharged through the nozzle 16.

[0037] Please see Figure 5 In an optional embodiment, the feeding pipe 11 is fixedly installed with the output end of the external pneumatic connector, which is used to transport the 3D printing consumables after preliminary hot melting into the inside of the feeding pipe 11, and then transport them through the feeding pipe 11 to the nozzle 16 for discharge, thereby completing the delivery of the 3D printing material.

[0038] Please see Figures 5 to 7 , Figure 10 as well as Figure 11 In an optional embodiment, the consumable material in a molten state after hot melting enters the flow channel through the feeding pipe 11. Since the flow channel 21 has an acceleration channel inside, which consists of a top frustum-shaped channel and a bottom trapezoidal channel, and the diameter of the top frustum-shaped channel gradually decreases from top to bottom, and the inner wall of the top frustum-shaped channel along the vertical direction is set as equidistant elliptical arc surfaces, the inner diameter of the major axis of the elliptical arc surfaces decreases sequentially, and the inner diameter of the bottom trapezoidal channel gradually increases along the vertical direction, as the material is conveyed by the feeding pipe 11, it will be accelerated by the acceleration channel inside the flow channel 21 after passing through the flow channel 21, so that the consumable material flows faster inside the flow channel 21 and avoids blockage of the feeding pipe 11.

[0039] By setting up the flow channel 21, the flow rate of the molten filament is accelerated. Accelerating the flow of filament can shorten the printing time of a single layer, which is especially suitable for large-size models or mass production scenarios. It significantly improves the overall printing speed. Accelerating the flow helps to reduce the residence time of the molten material in the nozzle 16, reducing the risk of degradation caused by prolonged heating, thereby improving the consistency of the extruded material and the molding quality.

[0040] In the acceleration channel, the diameter of the top frustum-shaped channel gradually decreases, which can compress the molten material to form a more concentrated flow core and reduce the probability of edge vortices. The equidistant distribution of the elliptical arc surface may further guide the laminar flow state and avoid local pressure fluctuations caused by sudden contraction. The design of the bottom trapezoidal channel with gradually increasing inner diameter may expand the flow cross-sectional area while maintaining the pressure gradient, thereby achieving secondary acceleration while ensuring continuous material supply. This staged variable diameter structure can control the flow velocity curve more accurately than a single conical pipe.

[0041] Please see Figures 5 to 7 , Figure 10 as well as Figure 11 In an optional embodiment, when the consumable material is accelerated through the flow pipe 21, it will come into contact with the spiral conveying channel 24 on the upper surface of the unblocking rod 23 and contact the surface trajectory of the spiral conveying channel 24. The molten consumable material has a certain pressure when it flows inside the feeding pipe 11. Therefore, after the pressure acts on the spiral conveying channel 24, it will act on the unblocking rod 23 through the spiral conveying channel 24, causing the unblocking rod 23 to move downward inside the positioning member 22.

[0042] Please see Figure 11 During the above process, as the unblocking rod 23 moves vertically downward, the spiral groove 26 on the outer surface of the unblocking rod 23 will cooperate with the guide rod 25, so that the interaction between the inclined surface of the spiral groove 26 and the guide rod 25 forces the unblocking rod 23 to rotate synchronously during the downward movement, thereby driving the spiral conveying channel 24 on its surface to rotate.

[0043] The rotation of the spiral conveying channel 24 generates shear force, which promotes uniform heating and stabilization of the molten state of the material. It is especially suitable for the initial transport of high-viscosity or infilled composite materials, avoiding material delamination during the initial 3D printing process. The rotation of the spiral conveying channel 24 also helps to scrape off residues from the inner wall of the flow channel, preventing blockage of the flow channel caused by long-term material accumulation. At the same time, the elliptical cross-section design reduces dead zones.

[0044] Please see Figure 11 In an optional embodiment, the downward movement of the unblocking rod 23 compresses the support spring 27 disposed between the unblocking rod 23 and the positioning member 22, causing the support spring 27 to contract and deform, and remain in a contracted state after the molten material is conveyed and formed through the feeding pipe 11.

[0045] The protective plate 28 is used to prevent the molten material from affecting the movement of the support spring 27 and causing damage to the support spring 27.

[0046] After 3D printing is completed and the consumables are delivered, the inside of the feeding pipe 11 is emptied. The pressure on the spiral conveying channel 24 and the unblocking rod 23 disappears, and the support spring 27 loses pressure and rebounds, causing the unblocking rod 23 and the spiral conveying channel 24 to return to their initial state. Due to the change in the elastic potential energy of the support spring 27, the support spring 27 will repeatedly undergo elastic deformation until the elastic potential energy of the support spring 27 disappears. In this state, the unblocking rod 23 will simultaneously perform reciprocating motion in the vertical direction.

[0047] Please see Figure 9 and Figure 10In an alternative embodiment, the bottom end of the unblocking rod 23 extends into the interior of the nozzle 16. When the molten consumable is conveyed through the feeding pipe 11, the presence of the unblocking rod 23 reduces the space of the internal channel of the nozzle 16, further increasing the pressure of the consumable ejected from the nozzle 16.

[0048] The reciprocating motion of the aforementioned unblocking rod 23 after the 3D printing process is completed, in conjunction with the spiral conveying channel 24, unblocks the inside of the nozzle 16, further preventing the consumable material from cooling inside the nozzle 16 after 3D printing and thus clogging the nozzle 16.

[0049] Further embodiments Please see Figure 7 and Figure 8 The 3D printing nozzle feeding device for PVC plastic also includes auxiliary components disposed inside the heating block 15; The auxiliary components include a receiving cavity 31 opened inside the bottom end of the heating block 15, a positioning ring 32 slidably connected inside the receiving cavity 31, a limit spring 33 attached to the top surface of the positioning ring 32, a snap-fit ​​block 34 fixedly connected to the bottom surface of the positioning ring 32, a piston sealing ring 35 attached to the outer side of the positioning ring 32, and a snap-fit ​​rod 36 fixedly installed on the upper surface of the nozzle 16.

[0050] The inner top wall of the positioning ring 32 and the side wall of the accommodating cavity 31 form a contraction cavity. The limiting spring 33 is disposed inside the contraction cavity, and the top end of the limiting spring 33 is attached to the top cavity wall of the accommodating cavity 31. The outer side wall of the positioning ring 32 and the accommodating cavity 31 form a heat preservation cavity. The outer wall of the snap-fit ​​block 34 and the two side cavity walls of the accommodating cavity 31 form a snap-fit ​​cavity.

[0051] The snap-fit ​​rod 36 is arranged symmetrically along the central axis of the snap-fit ​​block 34, and the top of the snap-fit ​​rod 36 is snapped and fixed to the snap-fit ​​block 34. The top outer wall of the nozzle 16 seals the snap-fit ​​cavity.

[0052] Please see Figure 7 and Figure 8 In an optional embodiment, the nozzle 16 is threaded into the inside of the throat 14. Therefore, as the nozzle 16 gradually approaches the throat 14, the locking rod 36 on the top of the nozzle 16 will cooperate with the locking block 34. Thus, through the cooperation of the locking rod 36 and the locking block 34, a locking structure is formed. After the threaded connection of the nozzle 16 is completed, the installation between the nozzle 16 and the throat 14 is further completed, preventing the nozzle 16 from becoming loose after long-term use.

[0053] Please see Figure 8In an optional embodiment, the movement of the latching rod 36 toward the latching block 34 will simultaneously compress the latching block 34 to move within the receiving cavity 31, and push the positioning ring 32 to move through the latching block 34, so that the positioning ring 32 abuts against the top cavity wall of the receiving cavity 31 until they are completely fitted.

[0054] Please see Figure 8 In an optional embodiment, the limiting spring 33, under the pressure of the positioning ring 32, contracts within the contraction cavity formed between the top inner wall of the positioning ring 32 and the side wall of the receiving cavity 31, while simultaneously applying pressure in the opposite direction to the positioning ring 32 and the snap-fit ​​block 34, thus reinforcing the threaded installation between the nozzle 16 and the throat 14.

[0055] Please see Figure 8 In an optional embodiment, the movement of the positioning ring 32 within the accommodating cavity 31 is restricted by the piston seal ring 35, which maintains a secure connection between the positioning ring 32 and the inner wall of the accommodating cavity 31 and enhances the sealing performance.

[0056] Please see Figure 8 In an optional embodiment, the outer wall of the positioning ring 32 forms a heat-insulating cavity with the accommodating cavity 31, the outer wall of the snap-fit ​​block 34 forms a snap-fit ​​cavity with the two side walls of the accommodating cavity 31, and the nozzle 16 seals the accommodating cavity 31, thereby achieving heat preservation of the nozzle 16 when the consumable is sprayed out.

[0057] The heat insulation cavity forms a heat insulation layer through the gap between the outer wall of the positioning ring 32 and the accommodating cavity 31, which reduces heat loss in the nozzle 16 area and avoids changes in material viscosity caused by temperature fluctuations, thereby ensuring extrusion smoothness and molding accuracy.

[0058] The sealing effect of the nozzle 16 on the accommodating cavity 31, combined with the surrounding layout of the insulation cavity, forms a double sealing system to maintain stability and further ensure the stability of the threaded connection of the nozzle 16.

[0059] The layered cavity structure (with the insulation cavity on the outside and the snap-fit ​​cavity on the inside) disperses the thermal expansion stress, avoids component deformation caused by repeated heating and cooling, and extends the service life of the nozzle 16 and the throat 14.

[0060] Example 2 A 3D printing nozzle includes a 3D printing nozzle feeding device for PVC plastic.

[0061] It should be noted that, in this document, 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.

[0062] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A 3D printing nozzle feeding device for PVC plastic, comprising a feeding pipe (11), characterized in that: A limiting block (12) is attached to the outside of the feeding pipe (11). A heat dissipation pipe (13) is threaded to the outer surface of the bottom end of the limiting block (12). A throat pipe (14) is attached to the inside of the heat dissipation pipe (13). A heating block (15) is detachably fixed to the outer surface of the bottom end of the throat pipe (14). A nozzle (16) is threaded to the inner surface of the bottom end of the throat pipe (14). A cleaning component is also provided inside the feeding pipe (11). The cleaning assembly includes a flow pipe (21) threaded to the inner wall of the bottom end of the throat (14), a positioning element (22) fixedly installed between the inner walls of the bottom end of the flow pipe (21), a dredging rod (23) is provided inside the positioning element (22), a spiral conveying channel (24) is fixedly connected to the outer surface of the top end of the dredging rod (23) in a centrally symmetrical manner, a guide rod (25) is fixedly connected to the inner wall of one side of the positioning element (22), a spiral groove (26) is opened on the outer surface of the dredging rod (23), a support spring (27) is sleeved on the outer surface of the dredging rod (23), and a protective plate (28) is fixedly connected to the outer surface of the dredging rod (23).

2. The 3D printing nozzle feeding device for PVC plastic according to claim 1, characterized in that: The limiting block (12), the throat (14), the heating block (15) and the nozzle (16) are arranged sequentially from top to bottom along the outer wall of the feeding pipe (11), and the inside of the top of the heat dissipation pipe (13) is engaged between the limiting block (12) and the throat (14).

3. The 3D printing nozzle feeding device for PVC plastics according to claim 1, characterized in that: One end of the feeding pipe (11) extends into the inside of the throat (14), and the end of the feeding pipe (11) inside the throat (14) abuts against the top surface of the flow pipe (21). The feeding pipe (11), the flow pipe (21) and the nozzle (16) arranged in sequence along the vertical direction are interconnected to form a conveying channel for 3D printing materials. An acceleration channel is opened inside the flow pipe (21), which consists of a top frustum-shaped channel and a bottom trapezoidal channel. The bottom surface of the flow pipe (21) abuts against the top surface of the nozzle (16).

4. The 3D printing nozzle feeding device for PVC plastic according to claim 3, characterized in that: The diameter of the top frustum channel in the acceleration channel gradually decreases from top to bottom, and the inner wall of the top frustum channel along the vertical direction is set as equidistant elliptical arc surfaces. The major axis of the inner diameter of the elliptical arc surfaces decreases sequentially. The inner diameter of the bottom truncate channel gradually increases along the vertical direction, and the inner diameter of the bottom of the bottom truncate channel is equal to the inner diameter of the top frustum channel.

5. A 3D printing nozzle feeding device for PVC plastics according to claim 3, characterized in that: The top of the unblocking rod (23) is located inside the acceleration channel, and the spiral conveying channel (24) is located inside the bottom of the top frustum channel. The size of the spiral conveying channel (24) is adapted to the bottom inner diameter of the top frustum channel in the acceleration channel of the flow pipe (21). The bottom of the unblocking rod (23) extends into the interior of the nozzle (16).

6. The 3D printing nozzle feeding device for PVC plastic according to claim 3, characterized in that: The flow channel (21) is located inside the bottom frustum channel. The guide rod (25) is slidably connected to the inside of the spiral groove (26). The support spring (27) is located inside the protective plate (28). The top of the support spring (27) abuts against the inner wall of the top of the protective plate (28), and the bottom of the support spring (27) abuts against the top surface of the flow channel (21). The protective plate (28) is slidably connected to the inside of the top of the flow channel (21).

7. The 3D printing nozzle feeding device for PVC plastic according to claim 1, characterized in that: It also includes auxiliary components disposed inside the heating block (15); The auxiliary components include a receiving cavity (31) opened inside the bottom end of the heating block (15), a positioning ring (32) is slidably connected inside the receiving cavity (31), a limit spring (33) is attached to the top surface of the positioning ring (32), a snap block (34) is fixedly connected to the bottom surface of the positioning ring (32), a piston seal ring (35) is attached to the outer side of the positioning ring (32), and a snap rod (36) is fixedly installed on the upper surface of the nozzle (16).

8. The 3D printing nozzle feeding device for PVC plastic according to claim 7, characterized in that: The inner top wall of the positioning ring (32) and the side wall of the accommodating cavity (31) form a shrinkage cavity. The limiting spring (33) is located inside the shrinkage cavity. The top of the limiting spring (33) fits against the top cavity wall of the accommodating cavity (31). The outer side wall of the positioning ring (32) and the accommodating cavity (31) form a heat preservation cavity. The outer wall of the snap-fit ​​block (34) and the two side cavity walls of the accommodating cavity (31) form a snap-fit ​​cavity.

9. A 3D printing nozzle feeding device for PVC plastics according to claim 8, characterized in that: The snap-fit ​​rod (36) is arranged symmetrically along the central axis of the snap-fit ​​block (34), and the top of the snap-fit ​​rod (36) is snapped and fixed to the snap-fit ​​block (34). The top outer wall of the nozzle (16) seals the snap-fit ​​cavity.

10. A 3D printing nozzle, characterized in that, The device comprises a 3D printing nozzle feeding device for PVC plastic as described in any one of claims 1-9.

Images