Hot end device of 3D printing equipment and 3D printing equipment

Abstract

The utility model discloses a hot end device of 3D printing equipment and the 3D printing equipment. The hot end device comprises a fixing piece, a heat dissipation mechanism, a heating mechanism, a nozzle and a conveying pipe. The heat dissipation mechanism is slidably connected to the fixing piece. The heating mechanism and the heat dissipation mechanism are arranged in a spaced mode and fixedly connected to the fixing part, the nozzle is arranged at the end, away from the heat dissipation mechanism, of the heating mechanism, the conveying pipe penetrates through the heat dissipation mechanism and the heating mechanism in the extending direction of the conveying pipe and communicates with the nozzle, and the conveying pipe is arranged to be capable of stretching and retracting in the extending direction. When the conveying pipe stretches, negative pressure is generated in the conveying pipe, so that the consumables in the nozzle are pumped back through the negative pressure. In this way, the printing quality of the 3D printing equipment can be improved.

Description

Technical Field

[0001] The present application relates to the field of 3D printing technology, and in particular to a hot end device of a 3D printing device and a 3D printing device. Background Art

[0002] With the development of science and technology and the progress of the times, 3D printing technology has developed rapidly. 3D printing equipment heats and transports printing consumables through a hot end device, processes the consumables through technologies such as fused deposition modeling, and finally forms a three-dimensional entity in three-dimensional space. It has a wide range of applications.

[0003] However, current 3D printing equipment is prone to wire drawing during the printing process, which makes it difficult to meet usage requirements. Utility Model Content

[0004] The main technical problem solved by the present application is to provide a hot end device of a 3D printing device and a 3D printing device, which can improve the printing quality of the 3D printing device.

[0005] In a first aspect, the present application provides a hot end device of a 3D printing device, which includes a fixing part, a heat dissipation mechanism, a heating mechanism, a nozzle, and a delivery pipe. The heat dissipation mechanism is slidably connected to the fixing part. The heating mechanism and the heat dissipation mechanism are arranged at intervals and fixedly connected to the fixing part. The nozzle is arranged at one end of the heating mechanism away from the heat dissipation mechanism. The delivery pipe passes through the heat dissipation mechanism and the heating mechanism along its extension direction and is connected to the nozzle. The delivery pipe is arranged to be able to telescopically move in the extension direction. When the delivery pipe is extended, negative pressure is generated in the delivery pipe to draw back the consumables in the nozzle through the negative pressure.

[0006] In a second aspect, the present application provides a 3D printing device, which includes a device body and a hot end device as described above, wherein the hot end device is connected to the device body.

[0007] The beneficial effects of the present application are as follows: different from the prior art, by setting a hot end device including a fixing part, a heat dissipation mechanism, a heating mechanism, a nozzle and a delivery pipe, wherein the delivery pipe is used to transport consumables, the nozzle is used to receive the consumables transported by the delivery pipe and spray them out, the delivery pipe is penetrated by the heat dissipation mechanism and the heating mechanism along its extension direction, the delivery pipe can telescope in its extension direction, and when the delivery pipe is extending, a negative pressure is generated inside the delivery pipe, that is, the air pressure inside the delivery pipe is lower than the external normal pressure at this time, so that the consumables in the nozzle will be subjected to a force to be drawn back toward the inside of the delivery pipe, so as to realize the consumables in the nozzle being drawn back by negative pressure, which is beneficial to reduce the possibility of the consumables in the molten state in the nozzle overflowing outward and causing wire drawing, effectively improving the accuracy of the printed model of the 3D printing device, and effectively improving the printing quality of the 3D printing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a three-dimensional structural schematic diagram of an embodiment of the 3D printing device of the present application;

[0009] Figure 2 yes Figure 1 A schematic diagram of the three-dimensional structure of the hot end device shown;

[0010] Figure 3 yes Figure 1 A schematic diagram of the disassembled structure of the hot end device shown;

[0011] Figure 4 yes Figure 2 A schematic diagram of the cross-sectional structure shown along the AA cutting line;

[0012] Figure 5 yes Figure 3 A front view schematic diagram of the delivery pipe;

[0013] Figure 6 yes Figure 3 Another front view schematic diagram of the delivery pipe;

[0014] Figure 7 yes Figure 3 Another front view schematic diagram of the delivery pipe;

[0015] Figure 8 yes Figure 3 Another schematic front view of the delivery tube. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0018] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0019] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0020] 3D printing equipment usually heats and transports consumables through a hot end device, and then processes the consumables through technologies such as fused deposition modeling to print out models. The consumables are the materials used for printing by 3D printing equipment, which are generally coils wrapped around a material tray. The consumables are squeezed and transported into the hot end device through an extruder, and the hot end device then heat-melts the input consumables and sprays them out from the nozzle to build the desired model.

[0021] In the process of printing a model with a 3D printing device, since the hot end device performs a heat-melting treatment on the input consumables, the consumables in the nozzle are in a molten state. When the 3D printing device controls the movement of the nozzle, the consumables in the molten state are easily overflowed from the nozzle due to the effect of their own gravity and the pressure generated by the phase change of the consumables due to heat inside the hot end device, thereby leaving unnecessary residues and filaments on the printed part, which is the so-called wire drawing phenomenon, affecting the quality of the model printed by the 3D printing device. In the related art, in order to improve the wire drawing phenomenon, an extruder is usually used to extrude the consumables in the opposite direction of the conveying direction so that the consumables are withdrawn to avoid the overflow of the molten consumables. However, the gears in the extruder repeatedly extrude the consumables, which will deteriorate the extrusion accuracy of the consumables and affect the printing quality of the 3D printing device. In addition, the extruder does not directly contact the nozzle, and the retraction force generated by the extruder extruding the consumables is difficult to be transmitted to the nozzle. The improvement of the wire drawing phenomenon is limited and it is difficult to meet the demand. Based on this, the present application proposes the following embodiments to solve the above technical problems.

[0022] The following 3D printing device embodiments of the present application describe an exemplary structure of a 3D printing device.

[0023] like Figure 1 and Figure 2 As shown, the 3D printing device 1 includes a device body 10 and a hot end device 20, and the hot end device 20 is connected to the device body 10. The device body 10 includes an extruder 11, a carrier platform 12, a motion system 13 and a controller 14, and the hot end device 20 includes a nozzle 220.

[0024] The extruder 11 is used to extrude and transport the consumables to the hot end device 20. The hot end device 20 is used to heat the consumables into a molten state, and use the nozzle 220 to spray the molten consumables to form fiber filaments, so as to spray the fiber filaments to a preset position of the carrier platform 12, so as to build a preset model on the carrier platform 12. The carrier platform 12 is used to carry the fiber filaments sprayed by the nozzle 220, and is the place where the fiber filaments are cooled and formed.

[0025] The motion system 13 is the basis for the 3D printing device 1 to perform three-dimensional parts. The motion system 13 can drive the nozzle 220 to move on the X-axis, Y-axis, and Z-axis, so that the nozzle 220 extrude the fiber filament at the corresponding position of the preset model.

[0026] The controller 14 is used to control the operation of the extruder 11 , the hot end device 20 and the motion system 13 , and is used to control the motion system 13 to move the nozzle 220 to a preset position to print a model.

[0027] like Figure 2 and Figure 3 As shown, the hot end device 20 includes a fixing member 100, a conveying mechanism 200, a heat dissipation mechanism 700 and a heating mechanism 800. The conveying mechanism 200 includes a conveying pipe 210 and a nozzle 220.

[0028] The heat dissipation mechanism 700 is slidably connected to the fixing member 100. The heating mechanism 800 is spaced apart from the heat dissipation mechanism 700 and fixedly connected to the fixing member 100. The nozzle 220 is arranged at one end of the heating mechanism 800 away from the heat dissipation mechanism 700, and the delivery pipe 210 is arranged along its extension direction F1 to penetrate the heat dissipation mechanism 700 and the heating mechanism 800, and the delivery pipe 210 is connected with the nozzle 220. The delivery pipe 210 is used to sequentially transport the consumables through the heat dissipation mechanism 700 and the heating mechanism 800 and transport them to the nozzle 220, and the nozzle 220 sprays the consumables to a preset position of the loading platform 12, so as to build a preset model on the loading platform 12. The delivery pipe 210 is arranged to be able to telescopically move in the extension direction F1, the heat dissipation mechanism 700 is arranged to be able to move relative to the fixing member 100, and then can drive the delivery pipe 210 to telescopically move, and at least a part of the heating mechanism 800 is arranged to be able to follow the telescopic movement of the delivery pipe 210 and move relative to the fixing member 100. When the delivery tube 210 is extended, negative pressure is generated in the delivery tube 210 to draw back the consumables in the nozzle 220 through the negative pressure.

[0029] Alternatively, if Figure 2 and Figure 3As shown, the heating mechanism 800 includes a first heating element 500 and a second heating element 600, which are spaced apart on the outer periphery of the delivery tube 210 along the extension direction F1 of the delivery tube 210, and are used to heat the consumables in the delivery tube 210 respectively, so as to heat the consumables into a molten state, so as to facilitate the nozzle 220 to spray out the fiber filaments for building the model. The first heating element 500 and the second heating element 600 spaced apart on the outer periphery of the delivery tube 210 can effectively improve the heating efficiency and heating quality of the consumables inside the delivery tube 210, facilitate the consumables to be heated into a molten state, and facilitate the subsequent nozzle 220 to spray out the consumables smoothly.

[0030] Furthermore, the delivery tube 210 is configured to be able to telescope in its extension direction F1. The delivery tube 210 is used to generate negative pressure inside when it is extended, that is, the air pressure inside the delivery tube 210 is lower than the external normal pressure when it is extended, so that the molten consumables in the nozzle 220 will be subjected to a force to be drawn back into the delivery tube 210, so as to achieve the consumables in the nozzle 220 to be drawn back by the negative pressure. When the delivery tube 210 is contracted, the negative pressure generated inside the delivery tube 210 will be restored to the air pressure that is balanced with the external normal pressure before the telescopic movement, so that the consumables re-enter the nozzle 220 and are ejected from the nozzle 220. By using negative pressure to draw back the consumables, the drawing back force can be better applied to the consumables in the nozzle 220 , which has high reliability and will not cause the extrusion accuracy of the consumables to deteriorate due to repeated squeezing of the consumables by the gears in the extrusion device 11 , thereby reducing the possibility of affecting the printing quality of the 3D printing device 1 due to the drawing back of the consumables, effectively improving the accuracy of the model printed by the 3D printing device 1 , and effectively improving the printing quality of the 3D printing device 1 .

[0031] Alternatively, if Figure 3 As shown, the delivery tube 210 includes a first tube body 211, a connecting tube body 212 and a second tube body 213 connected in sequence, the end of the first tube body 211 away from the second tube body 212 is fixedly connected to the heat dissipation mechanism 700, and the end of the second tube body 213 away from the first tube body 211 is fixedly connected to the heating mechanism 800. The first tube body 211 and the second tube body 213 can move relative to each other in the extension direction F1 to get closer to or away from each other, and the connecting tube body 212 is used to perform telescopic movement when the first tube body 211 and the second tube body 213 move relative to each other, so as to generate negative pressure during the extension movement. Optionally, the projection of the first tube body 211 and / or the second tube body 214 on a plane perpendicular to the extension direction F1 is located within the range of the projection of the connecting tube body 212 on a plane perpendicular to the extension direction F1.

[0032] Optionally, the heat dissipation mechanism 700 is sleeved on the outer periphery of the first tube body 211, and the heating mechanism 800 is sleeved on the outer periphery of the first tube body 211 and the second tube body 213. The first heating element 500 is sleeved on the outer periphery of the first tube body 211 and fixedly connected to the first tube body 211. The first tube body 211 and the first heating element 500 can be connected by riveting, bonding or other connection methods. The second heating element 600 is sleeved on the outer periphery of the second tube body 213 and fixedly connected to the second tube body 213. The second tube body 213 and the second heating element 600 can be connected by riveting, bonding or other connection methods. The second heating element 600 is fixedly connected to the nozzle 220.

[0033] Alternatively, if Figure 3 and Figure 4 As shown, the connecting tube body 212 is disposed between the first heating element 500 and the second heating element 600. The connecting tube body 212 is used to change the volume of the inner cavity 206 of the connecting tube body 212 through telescopic movement, so as to increase the volume of the inner cavity 206 during the extension movement to generate negative pressure, thereby withdrawing the consumables in the second tube body 213 and the nozzle 220. The first tube body 211 and the second tube body 213 are connected by the connecting tube body 212, and the size of the inner cavity 206 is achieved during the telescopic movement by using the connecting tube body 212. Specifically, when the delivery tube 210 is in the extension movement, the volume of the inner cavity 206 increases, thereby reducing the air pressure of the inner cavity 206 to generate negative pressure for withdrawing the consumables, and the operation is reliable and the withdrawal efficiency is high. The delivery tube 210 is divided into three parts: a first tube body 211, a connecting tube body 212 and a second tube body 213, and the connecting tube body 212 is arranged between the first heating element 500 and the second heating element 600. Compared with arranging the connecting tube body 212 for generating negative pressure at the end of the delivery tube 210 away from the nozzle 220, arranging the connecting tube body 212 in the middle section of the delivery tube 210 can make the inner cavity 206 generating negative pressure closer to the nozzle 220, so as to better apply the retraction force to the consumables in the nozzle 220, shorten the path of applying the retraction force, reduce the loss of the retraction force, effectively improve the retraction efficiency and the reliability of the retraction, and thus help to reduce the possibility of the molten consumables in the nozzle 220 overflowing and causing wire drawing, effectively improve the accuracy of the printed model of the 3D printing device 1, and effectively improve the printing quality of the 3D printing device 1.

[0034] Alternatively, if Figure 5As shown, the connecting pipe body 212 includes a first connecting pipe segment 2121 and a second connecting pipe segment 2122. The first connecting pipe segment 2121 is arranged in a trumpet shape from its first end 201 to the second end 202, and the second connecting pipe segment 2122 is arranged in a trumpet shape from its first end 201 to the second end 202. The first end 201 of the first connecting pipe segment 2121 is connected to the first pipe body 211, the first end 201 of the second connecting pipe segment 2122 is connected to the second pipe body 213, and the second end 202 of the first connecting pipe segment 2121 is connected to the second end 202 of the second connecting pipe segment 2122. When the connecting pipe body 212 telescopes, the first end 201 of the first connecting pipe segment 2121 and the first end 201 of the second connecting pipe segment 2122 are close to or away from each other to adjust the size of the inner cavity 206, thereby changing the air pressure of the inner cavity 206. In some embodiments, when the connecting tube body 212 is extending, the second ends 202 of the first connecting tube segment 2121 and the second connecting tube segment 2122 can, for example, move closer to the center of the connecting tube body 212 to expand the volume of the inner cavity 206. When the connecting tube body 212 is contracting, the second ends 202 of the first connecting tube segment 2121 and the second connecting tube segment 2122 can, for example, diffuse toward the periphery, thereby reducing the volume of the inner cavity 206 until the air pressure in the inner cavity 206 is the same as the normal pressure of the outside.

[0035] Alternatively, if Figure 6 As shown, the connecting tube body 212 is a metal elastic bellows that can be elastically stretched along the extension direction F1. When the connecting tube body 212 stretches, the metal elastic bellows is pulled open to increase the volume of the inner cavity 206, thereby reducing the air pressure in the inner cavity 206 to form a negative pressure.

[0036] Alternatively, if Figure 7 As shown, the connecting tube body 212 is a piston cylinder, and the connecting tube body 212 includes a piston 2123 and a cylinder body 2124. The piston 2123 is connected to the first tube body 211, and the cylinder body 2124 is connected to the second tube body 213. When the delivery tube 210 performs an extension movement, the first tube body 211 moves away from the second tube body 213 in the extension direction F1, thereby driving the piston 2123 to slide relative to the cylinder body 2124, so as to increase the volume of the inner cavity 206, thereby reducing the air pressure of the inner cavity 206 to form a negative pressure.

[0037] Alternatively, if Figure 8 As shown, the connecting tube body 212 is a retractable elastic tube, such as a plastic tube. When stretching, the first tube body 211 moves away from the second tube body 213 in the extension direction F1, thereby applying a pulling force to the connecting tube body 212, causing it to produce elastic deformation to increase the volume of the inner cavity 206, thereby reducing the air pressure in the inner cavity 206 to form a negative pressure.

[0038] Alternatively, if Figure 2 and Figure 3 As shown, the second heating element 600 is provided with a connecting column 610, and the connecting column 610 is fixedly connected to the fixing member 100, so that the nozzle 220 is fixedly connected to the fixing member 100 through the second heating element 600. The number of connecting columns 610 can be, for example, two, four, six, etc., which are symmetrically distributed. When the delivery tube 210 is telescopically moving, the first tube body 211 can move relative to the second tube body 213 in the extension direction F1, so that the first heating element 500 and the second heating element 600 can move relative to each other in the extension direction F1. By fixing one end of the delivery tube 210 and moving the other end relatively to achieve the telescopic movement of the delivery tube 210, compared with the simultaneous movement of both ends, the structure is more reliable, more conducive to the control of the negative pressure size, and conducive to improving the reliability of the use of the hot end device 20.

[0039] Alternatively, if Figure 2 and Figure 4 As shown, the heat dissipation mechanism 700 is fixedly sleeved on the outer periphery of the first tube body 211, and can move relative to the fixing member 100, thereby driving the delivery tube 210 to perform telescopic movement. In some embodiments, the heat dissipation mechanism 700 and the first tube body 211 are connected by a top screw, or can be bonded or connected in other ways. The heat dissipation mechanism 700 can be driven by a power source to drive the delivery tube 210 to perform telescopic movement, and the power source can be, for example, a motor, an electric spring, a hydraulic lifting and retracting rod, etc., of course, it can also be other power sources.

[0040] Furthermore, if Figure 2 and Figure 4 As shown, the hot end device 20 also includes a guide plate 400 and a guide member 310. The guide plate 400 is fixedly connected to the fixing member 100. The guide member 310 is slidably connected to the guide plate 400. The heat dissipation mechanism 700 is arranged opposite to the guide plate 400, and the side of the heat dissipation mechanism 700 away from the nozzle 220 is fixedly connected to the guide member 310. The guide member 310 is used to drive the heat dissipation mechanism 700 to slide relative to the guide plate 400, thereby driving the delivery pipe 210 to telescopic movement.

[0041] Specifically, the guide plate 400 is provided with a guide hole 203, and the guide member 310 is slidably disposed in the guide hole 203, and the guide hole 203 is used to guide the guide member 310 to slide in the extension direction F1. The guide member 310 slides in the guide hole 203 to drive the conveying tube 210 to perform telescopic movement. The structure is simple and effective, and it is convenient to position, install and disassemble. The overall structure is relatively stable, and the possibility of displacement or shaking of the conveying tube 210 during telescopic movement is reduced, which effectively improves the reliability of the retraction, effectively improves the accuracy of the printed model of the 3D printing device 1, and effectively improves the printing quality of the 3D printing device 1.

[0042] Alternatively, if Figure 4As shown, the heat dissipation mechanism 700 is provided with a plurality of heat dissipation plates 320 for dissipating the heat generated by the first heating element 500 and the second heating element 600, thereby reducing the possibility of the first heating element 500 and the second heating element 600 affecting the consumables outside the delivery tube 210 and improving the reliability of the delivery of the consumables.

[0043] Alternatively, if Figure 4 As shown, the guide plate 400 is provided with a delivery hole 204 spaced apart from the guide hole 203, and the delivery hole 204 is arranged opposite to the pipe opening 205 on the side of the delivery pipe 210 away from the nozzle 220, and is used to deliver the consumables to the delivery pipe 210. The delivery hole 204 can limit the consumables delivered into the delivery pipe 210, so that the consumables can smoothly enter the delivery pipe 210, and the consumables are not easy to shake or shift during the telescopic movement of the delivery pipe 210, thereby improving the reliability of the operation of the hot end device 20.

[0044] In summary, by setting the hot end device 20 including the fixing member 100, the heat dissipation mechanism 700, the heating mechanism 800, the nozzle 220 and the delivery pipe 210, wherein the delivery pipe 210 is used to transport the consumables, the nozzle 220 is used to receive the consumables transported by the delivery pipe 210 and spray them out, the delivery pipe 210 is arranged in the heat dissipation mechanism 700 and the heating mechanism 800 along its extension direction F1, and the delivery pipe 210 can be telescopically moved in its extension direction F1. When the delivery pipe 210 is stretched, negative pressure can be generated in its pipeline, that is, at this time, the air pressure inside the pipeline of the delivery pipe 210 is lower than the normal pressure of the outside, so that the consumables in the nozzle 220 will be affected by the consumables inside the pipeline of the delivery pipe 210. The retraction force is used to retract the consumables in the nozzle 220 through negative pressure, which is beneficial to reducing the possibility of the molten consumables in the nozzle 220 overflowing and causing wire drawing. Compared with the related art of retracting the consumables by squeezing the consumables in the opposite direction of the conveying direction through the extrusion device 11, the negative pressure retraction of the consumables can better apply a retraction force to the consumables in the nozzle 220, and the extrusion accuracy of the consumables will not deteriorate due to the repeated squeezing of the consumables by the gears in the extrusion device 11, thereby reducing the possibility of affecting the printing quality of the 3D printing device 1 due to the retraction of the consumables, effectively improving the accuracy of the printed model of the 3D printing device 1, and effectively improving the printing quality of the 3D printing device 1.

[0045] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A hot end device of a 3D printing device, characterized in that: include: Fixings; A heat dissipation mechanism, slidably connected to the fixing member; A heating mechanism is spaced apart from the heat dissipation mechanism and fixedly connected to the fixing member; A nozzle, arranged at an end of the heating mechanism away from the heat dissipation mechanism; A delivery pipe, wherein the delivery pipe passes through the heat dissipation mechanism and the heating mechanism along its extension direction and is connected to the nozzle, and the delivery pipe is configured to be able to telescopically move in the extension direction; wherein, when the delivery pipe is extended, negative pressure is generated in the delivery pipe to draw back the consumables in the nozzle through the negative pressure.

2. The hot end device according to claim 1, characterized in that: The heating mechanism comprises a first heating element and a second heating element, wherein the first heating element and the second heating element are sleeved on the outer circumference of the conveying tube at intervals along the extending direction, and are used to heat the consumables in the conveying tube respectively.

3. The hot end device according to claim 1, characterized in that: The delivery pipe includes a first pipe body, a connecting pipe body and a second pipe body connected in sequence, one end of the first pipe body away from the second pipe body is fixedly connected to the heat dissipation mechanism, and one end of the second pipe body away from the first pipe body is fixedly connected to the heating mechanism; wherein, The connecting tube body realizes the change of the volume of the inner cavity through telescopic movement. When the connecting tube body is extended, the volume of the inner cavity increases so that the air pressure in the inner cavity decreases, thereby generating negative pressure for withdrawing the consumables in the nozzle.

4. The hot end device according to claim 3, characterized in that: The projection of the first tube body and / or the second tube body on a plane perpendicular to the extending direction is located within the range of the projection of the connecting tube body on a plane perpendicular to the extending direction.

5. The hot end device according to claim 3, characterized in that: The heating mechanism includes a first heating element and a second heating element. The first heating element is fixedly connected to the first tube body, and the second heating element is fixedly connected to the second tube body and the nozzle. The connecting tube body is arranged between the first heating element and the second heating element.

6. The hot end device according to claim 5, characterized in that: The second heating element is provided with a connecting column, and the connecting column is fixedly connected to the fixing element so that the nozzle is fixedly connected to the fixing element via the second heating element; when the conveying tube moves in a telescopic manner, the first tube body can move relative to the second tube body in the extension direction, so that the first heating element and the second heating element can move relative to each other in the extension direction.

7. The hot end device according to claim 1, characterized in that: The hot end device also includes a guide plate and a guide member, wherein the guide plate is fixedly connected to the fixing member, and the guide member is slidably connected to the guide plate. The heat dissipation mechanism is arranged opposite to the guide plate, and the side of the heat dissipation mechanism away from the nozzle is fixedly connected to the guide member, and the guide member is used to drive the heat dissipation mechanism to slide relative to the guide plate, thereby driving the delivery pipe to telescopic movement.

8. The hot end device according to claim 7, characterized in that: The guide plate is provided with a guide hole, and the guide member is slidably inserted into the guide hole, and the guide hole is used to guide the guide member to slide in the extending direction.

9. The hot end device according to claim 8, characterized in that: The guide plate is provided with a delivery hole spaced apart from the guide hole, and the delivery hole is arranged opposite to the pipe opening of the delivery pipe on the side away from the nozzle, and is used for delivering consumables to the delivery pipe.

10. A 3D printing device, characterized in that: The 3D printing device comprises a device body and a hot end device as described in any one of claims 1 to 9, wherein the hot end device is connected to the device body.

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