Extrusion front shell for 3D printing head, 3D printing head and 3D printer

Abstract

An extrusion front shell suitable for a 3D printing head, the 3D printing head and the 3D printer, the first hot end assembly and the second hot end assembly in the 3D printing head can be switched to use, the extrusion front shell has a first air duct and a second air duct, the first air duct has a first air outlet, the second air duct has a second air outlet, the direction of the first air outlet forms a first included angle with the width direction of the 3D printing head, the direction of the second air outlet forms a second included angle with the opposite direction of the width direction of the 3D printing head, the first air outlet sprays the printing material in molten state sprayed by the first hot end assembly, and the second air outlet is used for spraying the printing material in molten state sprayed by the second hot end assembly; the first air duct can be used for air flow to cool the printing material in molten state sprayed by the first hot end assembly, the second air duct can cool the printing material in molten state sprayed by the second hot end assembly, accelerate the solidification of the three-dimensional product, shorten the solidification time of the three-dimensional product, and improve the quality of the three-dimensional product.

Description

Technical Field

[0001] This application relates to the field of 3D printing technology, and more particularly to an extrusion front shell suitable for a 3D print head, a 3D print head, and a 3D printer. Background Technology

[0002] A 3D print head heats the printing material (filament) to a molten state and then sprays the molten printing material onto a processing platform to form a three-dimensional product.

[0003] Currently, after molten printing material is sprayed onto the processing platform to form a 3D product, the solidification time of the molten printing material is often too long, causing the 3D product to deform during the solidification process, which has a negative impact on the quality of the 3D product. Utility Model Content

[0004] This application provides an extrusion front shell for a 3D print head, a 3D print head, and a 3D printer, which can accelerate the solidification of 3D products, shorten the solidification time of 3D products, and improve the quality of 3D products.

[0005] In a first aspect, this application provides an extrusion front shell suitable for a 3D printing head. The 3D printing head includes a connecting frame, a first hot end assembly, and a second hot end assembly. The first hot end assembly and the second hot end assembly are connected to the connecting frame, and at least one of the first hot end assembly and the second hot end assembly is movably connected to the connecting frame. The first hot end assembly is used to spray molten printing material, and the second hot end assembly is used to spray molten printing material. The extrusion front shell is detachably connected to the connecting frame. The extrusion front shell includes a first part, a second part, and a third part. The first part and the second part are spaced apart along the width direction of the 3D printing head. The third part connects the first part and the second part. The first hot end assembly and the second hot end assembly are spaced apart. The first part and the second part are located on opposite sides between the first hot end assembly and the second hot end assembly, respectively. The first part is provided with a first air duct that runs through the first part along the height direction of the 3D printing head. The first air duct has a first air outlet. The first air outlet is directed toward the molten printing material ejected from the first hot end component. The second part is provided with a second air duct that runs through the second part along the height direction of the 3D printing head. The second air duct has a second air outlet. The second air outlet is used to spray the molten printing material ejected from the second hot end component. The orientation of the first air outlet forms a first angle with the width direction of the 3D printing head, and the orientation of the second air outlet forms a second angle with the opposite direction of the width direction of the 3D printing head. The first angle and the second angle are different in size.

[0006] In conjunction with the first aspect, in one possible implementation, in the depth direction of the 3D printing head, the first part and the second part are located on the same side of the third part, the first part is provided with a first magnetic suction member on the side facing away from the third part, and the second part is provided with a second magnetic suction member on the side facing away from the third part. The connecting frame is equipped with a third magnetic component and a fourth magnetic component. The first magnetic component is attracted to the third magnetic component, and the second magnetic component is attracted to the fourth magnetic component.

[0007] In conjunction with the first aspect, in one possible implementation, the third part is provided with a third air duct that runs through the third part along the height direction of the 3D printing head.

[0008] In conjunction with the first aspect, in one possible implementation, the third air duct has a third air outlet, which is located between the first air outlet and the second air outlet in the projection of the 3D printing head in the depth direction.

[0009] In conjunction with the first aspect, in one possible implementation, a first fan is mounted on the extruded front housing, the first fan being used to input airflow into the first air duct, the second air duct, and the third air duct.

[0010] In conjunction with the first aspect, in one possible implementation, the first fan is located on the side of the first air duct away from the first air outlet, the first fan is located on the side of the second air duct away from the second air outlet, the third air duct has a third air outlet, and the first fan is located on the side of the third air duct away from the third air outlet.

[0011] In a second aspect, this application provides a 3D printing head, which includes a connector, a first hot end assembly, a second hot end assembly, and an extrusion front shell as described in the first aspect; The first hot end assembly and the second hot end assembly are connected to the connecting frame, and at least one of the first hot end assembly and the second hot end assembly is movably connected to the connecting frame; the extrusion front shell is detachably connected to the connecting frame.

[0012] In conjunction with the second aspect, in one possible implementation, the first hot end assembly includes a first heating block and a first nozzle, the first heating block being used to heat the first material line to a molten state, the first nozzle being used to spray the molten first material line, and the first air outlet facing the first nozzle. The second hot end assembly includes a second heating block and a second nozzle. The second heating block is used to heat the second material line to a molten state, and the second nozzle is used to spray the molten second material line. The second air outlet faces the second nozzle.

[0013] In conjunction with the second aspect, one possible implementation also includes a lifting mechanism. The first hot end component is connected to the connecting frame via the lifting mechanism, which is used to drive the first hot end component to move up and down. The second hot end component is fixedly connected to the connecting frame.

[0014] In conjunction with the second aspect, in one possible implementation, the activity trajectory of the first hot end component includes a first position and a second position, the first position being lower than the position of the second hot end component, the position of the second hot end component being lower than the second position, and when the first hot end component is in the first position, the first air outlet faces the first nozzle.

[0015] In conjunction with the second aspect, in one possible implementation, the first hot end assembly further includes a first feed channel and a first heat sink disposed around the periphery of the first feed channel, a first heating block connected between the first feed channel and the first nozzle, and the 3D printing head further includes a second fan blowing air toward the first heat sink.

[0016] In conjunction with the second aspect, in one possible implementation, the second hot end assembly further includes a second feed channel and a second heat sink disposed around the periphery of the second feed channel, the second heating block is connected between the second feed channel and the second nozzle, and the 3D printing head further includes a third fan that blows air toward the second heat sink.

[0017] Thirdly, this application provides a 3D printer that includes a 3D print head as described in the second aspect.

[0018] In this solution, the first hot end component and the second hot end component in the 3D printing head can be switched. The extrusion front shell has a first air duct and a second air duct. The first air duct has a first air outlet, and the second air duct has a second air outlet. The orientation of the first air outlet forms a first angle with the width direction of the 3D printing head, and the orientation of the second air outlet forms a second angle with the opposite direction of the width direction of the 3D printing head. The first angle and the second angle are different in size. The first air outlet is used to spray molten printing material from the first hot end component, and the second air outlet is used to spray molten printing material from the second hot end component. The first air duct can supply airflow to cool the molten printing material sprayed by the first hot end component, and the second air duct can cool the molten printing material sprayed by the second hot end component, thereby accelerating the solidification of the 3D product, shortening the solidification time of the 3D product, and improving the quality of the 3D product. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a 3D printer provided in one embodiment of this application; Figure 2 This is a schematic diagram of the structure of a 3D printing head provided in one embodiment of this application; Figure 3 This is a schematic diagram of the structure of a first extrusion assembly provided in an embodiment of this application; Figure 4 for Figure 3 Top view of the first extrusion assembly; Figure 5 This is a schematic diagram of the structure of a second extrusion assembly provided in an embodiment of this application; Figure 6 A partial structural schematic diagram of a 3D printing head provided in one embodiment of this application; Figure 7 A schematic diagram of the structure when the 3D printing head collides with the collision mechanism according to an embodiment of this application; Figure 8 This is a schematic diagram of the connection between the lifting mechanism and the first hot end assembly according to an embodiment of this application; Figure 9 This is a schematic diagram of the structure of a first hot-end component located at a first position according to an embodiment of this application; Figure 10 A schematic diagram of the structure of the first hot end component located at the second position according to an embodiment of this application; Figure 11 This is a structural schematic diagram of a connecting frame connecting lifting mechanism provided in an embodiment of this application; Figure 12 A partial structural schematic diagram of a 3D printing head provided in one embodiment of this application from another perspective; Figure 13 A partial structural schematic diagram of a 3D printing head provided in one embodiment of this application from another perspective; Figure 14 A partial structural schematic diagram of a 3D printing head provided in one embodiment of this application; Figure 15 for Figure 2 A structural schematic diagram of the 3D printing head from another perspective; Figure 16 A top view of the extruded front shell provided in an embodiment of this application; Figure 17 A three-dimensional structural schematic diagram of the extruded front shell provided in an embodiment of this application; Figure 18 This is a partial structural schematic diagram of a 3D printing head provided in one embodiment of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0022] Please see Figure 1This application provides a 3D printer 1, which may include a first extrusion assembly 11, a drive member 12, a guide member 14 and a 3D printing head 13. The first extrusion assembly 11 and the 3D printing head 13 are separated. The 3D printing head 13 is slidably disposed on the guide member 14, and the drive member 12 is connected to the 3D printing head 13 in a transmission connection.

[0023] Please see Figure 2 The 3D printing head 13 includes a connecting frame 131, a first hot-end assembly 132, a second hot-end assembly 133, and a second extrusion assembly 134. The first hot-end assembly 132, the second hot-end assembly 133, and the second extrusion assembly 134 are connected to the connecting frame 131. The first extrusion assembly 11 drives a first feed line 2 to convey the first feed line 2 to the first hot-end assembly 132, and the second extrusion assembly 134 drives a second feed line 3 to convey the second feed line 3 to the second hot-end assembly 133. At least one of the first hot-end assembly 132 and the second hot-end assembly 133 is movably connected to the connecting frame 131. For example, the first hot-end assembly 132 is movably connected to the connecting frame 131, and the second hot-end assembly 133 is fixedly connected to the connecting frame 131. Alternatively, the first hot-end assembly 132 is movably connected to the connecting frame 131, and the second hot-end assembly 133 is also movably connected to the connecting frame 131.

[0024] In some feasible implementations, the guide 14 can be a carbon rod or a linear guide, and the connecting frame 131 is provided with a through hole for the carbon rod or linear guide to pass through, thereby realizing the sliding connection of the 3D printing head 13 to the guide 14.

[0025] In the embodiments provided in this application, the 3D printer 1 may further include a processing platform, on which the 3D print head 13 prints the product during printing. During the printing process, the first hot-end component 132 heats the first filament 2 to a molten state and then sprays the molten filament onto the processing platform to process the product. The second hot-end component 133 heats the second filament 3 to a molten state and then sprays the molten second filament 3 onto the processing platform to process the product. The processing platform can be raised and lowered; as the printed product gradually thickens during printing, the processing platform can gradually descend to ensure that the 3D print head 13 remains above the product. The above description pertains to core xy structure 3D printers. In some feasible implementations, in cantilever or gantry 3D printers, the first and second hot-end components can heat the filament to a molten state and spray it onto the processing platform. During the process of the hot-end components spraying the molten filament onto the processing platform, the processing platform can move along the y-axis, while the 3D print head moves up and down along the Z-axis and along the X-axis to achieve the processing of three-dimensional objects. The accompanying drawings of this application use a core xy structure 3D printer as an example and do not constitute a limitation on the 3D printer structure of this application. The solution of this application can be applied to other structures such as cantilever and gantry 3D printers.

[0026] The 3D printing head 13 can switch between using the first hot end assembly 132 and the second hot end assembly 133, thereby switching the material line ejected onto the processing platform to form a product. For example, a product can be formed by processing a first wire 2 and a second wire 3. By using the 3D printing head 13 to switch between the first hot end component 132 and the second hot end component 133, the first wire 2 and the second wire 3 can be melted alternately (wherein, the first hot end component 132 can heat the first wire 2 to make it molten, and the second hot end component 133 can heat the second wire 3 to make it molten). The first hot end component 132 sprays the molten first wire 2 onto the processing platform, and the second hot end component 133 sprays the molten second wire 3 onto the processing platform. The molten first wire 2 and the second wire 3 form a product on the processing platform, thereby improving processing efficiency and reducing waste. This is because by adding hot end components, different hot end components can be used to heat different wires. For example, heating wires of different colors eliminates the need to increase rinsing time and waste rinsing wire to clean the residue of the previous wire in the hot end component.

[0027] For example, when printing a product, the 3D printing head 13 ejects material through the first hot end assembly 132 or the second hot end assembly 133. The driving member 12 drives the 3D printing head 13 to move along a preset trajectory. The driving member 12 can drive the 3D printing head 13 to move along a first direction (e.g., the X-axis direction) or a second direction (e.g., the Y-axis direction). When the first hot end assembly 132 is ejecting the first molten material line 2, the 3D printing head 13 moves along a part of the preset trajectory. When the second hot end assembly 133 is ejecting the second molten material line 3, the 3D printing head 13 moves along another part of the preset trajectory.

[0028] In the embodiments provided in this application, when the first hot-end assembly 132 is in the first molten material line 2 in the sprayed state, the first material line 2 can be conveyed to the first hot-end assembly 132 by the first extrusion assembly 11. For details, please refer to... Figure 3 and Figure 4 The first extrusion assembly 11 includes a first motor 111, an extrusion wheel 112, and an extrusion wheel 113. The first motor 111 is drivenly connected to the extrusion wheel 112. In some feasible embodiments, the first motor 111 may be drivenly connected to the extrusion wheel 113. Alternatively, the first motor 111 may be drivenly connected to both the extrusion wheel 112 and the extrusion wheel 113.

[0029] For example, the outer peripheral surface of extrusion wheel 112 may be spaced apart from the outer peripheral surface of extrusion wheel 113. A gap is formed between extrusion wheel 112 and extrusion wheel 113 for the first feed line 2 to pass through, and the first feed line 2 contacts the outer peripheral surfaces of both extrusion wheel 112 and extrusion wheel 113 simultaneously, with both outer peripheral surfaces jointly clamping the first feed line 2. First motor 111 drives extrusion wheel 112 to rotate, and the first feed line 2 is conveyed through the clamping friction of extrusion wheel 112 and extrusion wheel 113, for example, conveying the first feed line 2 from the first extrusion assembly 11 to the first hot end assembly 132. Alternatively, first motor 111 drives extrusion wheel 112 and extrusion wheel 113 simultaneously, and the first feed line 2 is conveyed to the first hot end assembly 132 through the clamping and conveying of the first feed line 2 by extrusion wheel 112 and extrusion wheel 113.

[0030] When the second hot-end assembly 133 is in the second molten material line 3, the second material line 3 can be conveyed to the second hot-end assembly 133 through the second extrusion assembly 134. (See also...) Figure 5The second extrusion assembly 134 includes a second motor 1341, an extrusion wheel 1342, and an extrusion wheel 1343. The second motor 1341 drives the extrusion wheel 1342 to rotate. The outer peripheral surface of the extrusion wheel 1342 is spaced apart from the outer peripheral surface of the extrusion wheel 1343. The gap between the outer peripheral surfaces of the extrusion wheel 1342 and the extrusion wheel 1343 allows the second feed line 3 to pass through. The second feed line 3 is in contact with both the outer peripheral surfaces of the extrusion wheel 1342 and the extrusion wheel 1343, and the outer peripheral surfaces of both wheels clamp the second feed line 3 together. The second motor 1341 drives the extrusion wheel 1342 to rotate. Through the clamping friction of the extrusion wheel 1342 and the extrusion wheel 1343 on the second feed line 3, the second feed line 3 is conveyed, for example, from the second extrusion assembly 134 to the second hot end assembly 133. Alternatively, the second motor 1341 can simultaneously drive the extrusion wheel 1342 and the extrusion wheel 1343 to rotate, and convey the second material line 3 to the second hot end assembly 133 by clamping and conveying it through the extrusion wheel 1342 and the extrusion wheel 1343.

[0031] In this application, the 3D printer 1 has two extrusion components. The second extrusion component 134 is disposed in the 3D print head 13, that is, the second extrusion component 134 is disposed close to the second hot end component 133. The first extrusion component 11 is not disposed in the 3D print head 13, that is, the first extrusion component 11 is disposed relatively far from the first hot end component 132. It can be seen that the 3D printer provided in this application can include a dual hot end printer with one near-field extrusion and one far-field extrusion. When the drive member 12 drives the 3D print head 13, the first extrusion component 11 does not need to move with the 3D print head 13 on the guide member 14, which can reduce the output burden of the drive member 12 in driving the 3D print head 13. The fact that the first extrusion component 11 is not integrated into the 3D print head 13 can also reduce the size and weight of the 3D print head 13, avoid the 3D print head 13 being too bulky under the drive of the drive member 12, and improve the movement speed of the 3D print head 13 when printing products. Therefore, this application can achieve the benefits of dual-hot-end printers, such as improved processing efficiency and reduced waste, while avoiding the problems caused by existing dual-hot-end printers that place both extrusion components on the 3D print head, such as the 3D print head being too bulky and large, resulting in a decrease in the movement speed of the 3D print head 13 and a decrease in control precision.

[0032] In the embodiments provided in this application, the 3D printer 1 is also connected to a feeding device. The first hot end assembly 132 and the second hot end assembly 133 in the 3D print head 13 are respectively connected to the feeding device through the first feed tube 1a and the second feed tube 1b. The feeding device can accommodate the first feed line 2 and the second feed line 3. The feeding device can release the first feed line 2 and the second feed line 3. The first feed line 2 extends from the feeding device, passes through the first feed tube 1a, and is conveyed to the first hot end assembly 132 by the first extrusion assembly 11. The first hot end assembly 132 heats the first feed line 2 and sprays the molten first feed line 2. The first extrusion assembly 11 can drive the first feed line 2 and convey the first feed line 2 to the first hot end assembly 132. The second feed line 3 extends from the feeding device, passes through the second feed tube 1b, and is conveyed by the second extrusion assembly 134 to the second hot end assembly 133. The second hot end assembly 133 heats the second feed line 3 and sprays the molten second feed line 3. The second extrusion assembly 134 can drive the second feed line 3 and convey the second feed line 3 to the second hot end assembly 133.

[0033] In a 3D print head with dual hot-end components, the position of the hot-end component in the working state is lower than the position of the hot-end component in the idle state. For example, when the 3D print head 13 uses the first hot-end component 132 to spray the first molten material filament 2, the lowest point of the second hot-end component 133 is higher than the lowest point of the first hot-end component 132. During the movement of the 3D print head 13, the drive member 12 can prevent interference (e.g., collision) between the second hot-end component 133 and the product. When processing the product, the lowest point of the first hot-end component 132 is slightly higher than the product to improve processing accuracy. If the lowest point of the second hot-end component 133 is lower than the lowest point of the first hot-end component 132, the lowest point of the second hot-end component 133 may be lower than the product, causing interference between the 3D print head 13 and the product during movement.

[0034] When the 3D printing head 13 uses the second hot end component 133 to spray the second material line 3 in a molten state, the lowest point of the first hot end component 132 needs to be higher than the lowest point of the second hot end component 133. This can prevent the lowest point of the first hot end component 132 from being lower than the product. During the movement of the 3D printing head 13, interference (e.g., collision) between the first hot end component 132 and the product can be prevented.

[0035] In the embodiments provided in this application, the first hot-end component 132 is movably connected to the connecting frame 131, and the second hot-end component 133 is fixedly connected to the connecting frame 131. By changing the relative position of the first hot-end component 132 and the connecting frame 131, for example, by raising and lowering the first hot-end component 132 relative to the processing platform on the connecting frame 131, the relative height of the first hot-end component 132 and the second hot-end component 133 can be changed. For example, when the 3D printing head 13 uses the first hot-end component 132 to eject the first material line 2, the relative position of the first hot-end component 132 and the connecting frame 131 can be adjusted so that the lowest point of the first hot-end component 132 is lower than the lowest point of the second hot-end component 133. When the 3D printing head 13 uses the second hot-end component 133 to eject the second material line 3, the relative position of the first hot-end component 132 and the connecting frame 131 can be adjusted so that the lowest point of the first hot-end component 132 is higher than the lowest point of the second hot-end component 133. It is understood that the height difference between the first hot-end assembly 132 and the second hot-end assembly 133 is in the Z-axis direction. Implementing this application, the use of a liftable, movable first hot-end assembly 132 in conjunction with a remote extrusion assembly, such as a first extrusion assembly, ensures the printing effect of the fixed first hot-end assembly 132 and the near-field extrusion second hot-end assembly 133. This is particularly suitable for using the first hot-end assembly 132 to spray support material and the second hot-end assembly 133 to spray the main body components of the 3D product. This is because the first extrusion assembly 11 is relatively far from the first hot-end assembly 132, making it difficult to control the feed rate of the first material line 2 and guarantee print quality. However, it can be used to print support parts that need to be disassembled from the main body of the product, without affecting the appearance of the 3D product due to print quality issues.

[0036] In some embodiments, the 3D printing head 13 further includes a lifting mechanism 135 connected to the connecting frame 131. The lifting mechanism can be connected to at least one of the first hot end assembly 132 and the second hot end assembly 133. For example, please refer to [link to example]. Figure 6 and Figure 7 The 3D printing head 13 also includes a lifting mechanism 135 connected to the connecting frame 131. Figure 6 The following description uses the connection between the lifting mechanism 135 and the first hot-end component 132 as an example. Optionally, in some other embodiments, the lifting mechanism 135 may be connected to the second hot-end component 133. The 3D printer 1 may also include a housing 15 and a collision mechanism 16. The lifting mechanism 135 includes a trigger 1351, which is used to collide with the collision mechanism 16 to drive the hot-end component movably connected to the connecting frame 131 to move up and down. The collision mechanism 16 is mounted on the housing 15.

[0037] In the embodiments provided in this application, the housing 15 may include a base 151, and a processing platform is connected to the base 151. For example, the processing platform may be connected to the base 151 via a lead screw or a slider. The 3D printing head 13 may move relative to the housing 15 along at least one of a first direction (e.g., the X-axis direction) and a second direction (e.g., the Y-axis direction), wherein the first direction and the second direction are perpendicular to each other.

[0038] In one feasible implementation, please refer to Figure 8 The lifting mechanism 135 is connected to the first hot-end component 132. The first hot-end component 132 and the second hot-end component 133 are spaced apart. The second hot-end component 133 is fixed to the connecting frame 131. The lifting mechanism 135 is used to drive the first hot-end component 132 to move up and down. The first hot-end component 132 moves up and down along the Z-axis. By driving the first hot-end component 132 to move up and down through the lifting mechanism 135, the height position of the first hot-end component 132 is changed, thereby changing the relative height position of the first hot-end component 132 and the second hot-end component 133. In another feasible implementation, the lifting mechanism 135 is connected to the first hot end component 132 and also to the second hot end component 133. When the lifting mechanism 135 raises the first hot end component 132, it also raises the second hot end component 133. When the lifting mechanism 135 raises the second hot end component 133, it also raises the first hot end component 132. The first hot end component 132 and the second hot end component 133 can be connected to the two ends of the lifting mechanism 135 respectively.

[0039] Please see Figure 9 and Figure 10 In the embodiments provided in this application, the 3D printing head 13 further includes a connecting frame 131a that is detachably connected to the connecting frame 131, and a lifting mechanism 135 that is rotatably connected to the connecting frame 131a. The lifting mechanism 135 changes the height position of the first hot end assembly 132 and the second hot end assembly 133 by rotating relative to the connecting frame 131a.

[0040] In the embodiments provided in this application, during the lifting and lowering movement of the first hot-end component 132, the trajectory of the first hot-end component 132 includes a first position and a second position. The first position is lower than the second position. The first position can be the lowest position of the first hot-end component 132 during the lifting and lowering movement. When the first hot-end component 132 is in the first position, it is used to spray molten printing material (first feed line 2). The second position can be the highest position of the first hot-end component 132 during the lifting and lowering movement. When the second hot-end component 133 is fixedly connected to the connecting frame 131, the first position is lower than the location of the second hot-end component 133, and the second position is higher than the location of the second hot-end component 133. When the first hot-end component 132 is in the second position, it is used to spray molten printing material (second feed line 3).

[0041] In some embodiments, please continue to see Figure 8 The lifting mechanism 135 includes a gear 1352, and a rack 1321 is fixedly connected to the first hot end assembly 132. The gear 1352 meshes with the rack 1321. The lifting mechanism 135 also includes a first rotating shaft 1353, and a trigger 1351 includes a lever. The first rotating shaft 1353 passes through the gear 1352 and is fixed to the gear 1352. The trigger 1351 is fixedly connected to the first rotating shaft 1353. Specifically, one end of the lever is used to be fixedly connected to the first rotating shaft 1353, and the other end of the lever is used to collide with the collision mechanism 16.

[0042] When the lever collides with the collision mechanism 16, the lever is actuated. The lever drives the gear 1352 to rotate via the first rotating shaft 1353. During the rotation, the gear 1352 drives the rack 1321 to rise and fall, thereby driving the first hot end assembly 132 to rise and fall.

[0043] In some embodiments, the lifting mechanism 135 includes a drive wheel, a driven wheel, and a transmission belt. The drive wheel is connected to a trigger 1351, and the drive wheel and the driven wheel are connected by transmission belt. The trigger 1351 collides with the collision mechanism 16. The trigger 1351 can drive the drive wheel to rotate and drive the transmission belt to move up and down. The transmission belt can be connected to the first hot end assembly 132 and drive the first hot end assembly 132 to move up and down.

[0044] In some embodiments, the lifting mechanism 135 may include a cam and a push rod. The cam may be hinged to the push rod. The end of the push rod away from the cam is connected to the first hot end assembly 132. The cam is also connected to a trigger 1351. The trigger 1351 collides with the collision mechanism 16 to drive the cam to rotate. When the cam rotates, the end of the push rod away from the cam can move up and down in a straight line, thereby driving the first hot end assembly 132 to move up and down.

[0045] In some embodiments, the first hot-end component 132 is detachably connected to a first mounting position and a second mounting position of the connecting frame 131. When the first hot-end component 132 is detachably connected to the first mounting position, its position is lower than that of the second hot-end component 133. When the first hot-end component 132 is detachably connected to the second mounting position, its position is higher than that of the second hot-end component 133. When the first hot-end component 132 is detachably connected to the first mounting position, the 3D printing head 13 can use the first hot-end component 132 to spray molten printing material (first feed line 2). When the first hot-end component 132 is not mounted on the connecting frame 131 or is detachably connected to the second mounting position, the 3D printing head 13 can use the second hot-end component 133 to spray molten printing material (second feed line 3).

[0046] In some embodiments, please combine Figure 8 , Figure 9 and Figure 10 The lifting mechanism 135 may include a gear 1352, a second rotating shaft 1354, a first connecting rod 1355, a second connecting rod 1356, and a third connecting rod 1357. A rack 1321 is fixed to the first hot-end assembly 132, and the gear 1352 meshes with the rack 1321. The trigger 1351 includes a lever. The first rotating shaft 1353 and the second rotating shaft 1354 are spaced apart. The first end of the first connecting rod 1355 is hinged to the first rotating shaft 1353, the second end of the first connecting rod 1355 is hinged to the first end of the second connecting rod 1356, the second end of the second connecting rod 1356 is hinged to the first end of the third connecting rod 1357, and the second end of the third connecting rod 1357 is hinged to the second rotating shaft 1354. The first rotating shaft 1353 and the second rotating shaft 1354 are rotatably connected to the connecting frame 131a. The first rotating shaft 1353, the second rotating shaft 1354, the first connecting rod 1355, the second connecting rod 1356, and the third connecting rod 1357 can form a five-bar linkage, which can limit the rotation angle of the gear 1352, improve the motion accuracy of the lifting mechanism 135, and make the rotation process of the gear 1352 more stable.

[0047] In some embodiments, the lifting mechanism 135 further includes a plug 1358 connected to the second connecting rod 1356; the first hot end assembly 132 includes a first nozzle 1322 and a first heating block 1323, the first heating block 1323 is used to heat the first feed line 2 to a molten state, and the first nozzle 1322 is used to spray the molten first feed line 2; the second hot end assembly 133 includes a second nozzle 1331 and a second heating block 1332, the second heating block 1332 is used to heat the second feed line 3 to a molten state, and the second nozzle 1331 is used to spray the molten second feed line 3; the first nozzle 1322 and the second nozzle 1331 are spaced apart, when the first hot end assembly 132 is in the first position, the plug 1358 blocks the second nozzle 1331, and when the first hot end assembly 132 is in the second position, the plug 1358 blocks the first nozzle 1322. The first hot-end assembly 132 sprays molten first filament 2 onto the processing platform through the first nozzle 1322, and the second hot-end assembly 133 sprays molten second filament 3 onto the processing platform through the second nozzle 1331. During the process of switching the hot-end assembly of the 3D print head 13 to spray printing material, the lifting mechanism 135 moves so that the position of the hot-end assembly that needs to spray printing material is lower than the position of the hot-end assembly in the idle state (when no printing material needs to be sprayed). For example, in the 3D print head 13, if the first hot-end assembly 132 that needs to spray printing material is switched to the second hot-end assembly 133, the trigger 1351 can collide with the collision mechanism 16, causing the lifting mechanism 135 to lift the first hot-end assembly 132 to the second position. At the same time, the plug 1358, which moves with the second connecting rod 1356, moves to the bottom of the first hot-end assembly 132 and seals the first hot-end assembly 132. If the second hot end assembly 133 that needs to spray printing material is switched to the first hot end assembly 132, the trigger 1351 can collide with the collision mechanism 16, causing the lifting mechanism 135 to drive the first hot end assembly 132 down to the second position. At the same time, the plug 1358 that moves with the second link 1356 moves to the bottom of the second hot end assembly 133 and seals the second hot end assembly 133.

[0048] Specifically, when the trigger 1351 collides with the collision mechanism 16, the trigger 1351 is actuated, which in turn drives the first rotating shaft 1353 to rotate. The rotation of the first rotating shaft 1353 drives the first connecting rod 1355 to swing, which in turn drives the second connecting rod 1356 to swing. The swing of the second connecting rod 1356 drives the nozzle plug 1358 to move. At the same time, the rotation of the first rotating shaft 1353 also drives the gear 1352 to rotate. The gear 1352 meshes with the rack 1321, and the gear 1352 drives the rack 1321 to rise and fall along the Z-axis, thereby causing the entire first hot end assembly 132 to rise and fall. When the first hot end assembly 132 moves to the first position, the nozzle plug 1358 moves with the second connecting rod 1356 to the bottom of the second nozzle 1331 and blocks the second nozzle 1331, preventing the second nozzle 1331 from spraying out the molten second material line 3. When the first hot end assembly 132 moves to the second position, the plug 1358 moves with the second connecting rod 1356 to the bottom of the first nozzle 1322 and blocks the first nozzle 1322 to prevent the first nozzle 1322 from spraying out the first material line 2 in a molten state.

[0049] The upper surface of the plug 1358 is provided with a silicone sheet 1359. When the first hot end assembly 132 is in the first position, the silicone sheet 1359 is in contact with the second nozzle 1331. When the first hot end assembly 132 is in the second position, the silicone sheet 1359 is in contact with the first nozzle 1322.

[0050] For example, the silicone sheet 1359 can form a soft wrap around the nozzle when it is necessary to seal the nozzle. The silicone sheet 1359 can effectively seal the nozzle. For instance, when the first hot end assembly 132 is in the first position, the silicone sheet 1359 contacts the second nozzle 1331, effectively sealing the second nozzle 1331. When the first hot end assembly 132 is in the second position, the silicone sheet 1359 contacts the first nozzle 1322, effectively sealing the first nozzle 1322. In addition, the silicone sheet 1359 can provide soft contact between the plug and the nozzle, avoiding damage to the nozzle due to excessive stiffness.

[0051] Please refer to the embodiments provided in this application. Figure 11The gear 1352 is equipped with a circular magnet 13521. Two sensors 1311 for detecting changes in the magnetic field are mounted on the connecting frame 131a, both located on the outer periphery of the circular magnet 13521 and perpendicularly positioned. The two sensors 1311 can be Hall effect sensors. When the circular magnet 13521 rotates, the two sensors 1311 generate pulse signals due to the change in the magnetic field. Since the two Hall effect sensors 1311 are positioned at 90°, they can sense the components of the rotating magnetic field in two orthogonal directions, and then calculate the rotation angle of the gear 1352 through mathematical calculations (usually an arctangent function). For example, the connecting frame 131a includes a circuit board, on which the two sensors 1311 can be placed. For example, the rotation angle of gear 1352 can be obtained by two sensors to determine whether the first shaft 1353 and the second shaft 1354 have rotated into place, thereby knowing whether the first hot end assembly 132 and the second hot end assembly 133 are in the right position.

[0052] In some embodiments, please combine Figure 8 and Figure 12 The 3D printing head 13 further includes a first base 137 detachably connected to the first hot end assembly 132, the first base 137 being slidably connected to the connecting frame 131a; and / or, the 3D printing head 13 further includes a second base 138 detachably connected to the second hot end assembly 133, the second base 138 being fixedly connected to the connecting frame 131a. The connecting frame 131a is movably connected to the first hot end assembly 132 via the first base 137, and the connecting frame 131a is detachably connected to the second hot end assembly 133 via the second base 138.

[0053] Specifically, one of the first base 137 and the connecting frame 131a is provided with a slide rail 1312 and the other is provided with a slide groove 1371, with the slide rail 1312 and the slide groove 1371 slidingly engaged.

[0054] In one feasible implementation, the first base 137 is provided with a slide rail 1312, and the connecting frame 131a is provided with a slide groove 1371, with the slide rail 1312 and the slide groove 1371 slidingly engaged. In another feasible implementation, the first base 137 is provided with a slide groove 1371, and the connecting frame 131a is provided with a slide rail 1312, with the slide rail 1312 and the slide groove 1371 slidingly engaged.

[0055] The connecting bracket 131a is provided with an abutment member 1313, which is disposed above the first base 137, and the first base 137 is in movable contact with the abutment member 1313. The abutment member 1313 is used to limit the extreme position of the first hot end assembly 132, wherein the extreme position of the first hot end assembly 132 can be a second position.

[0056] At least one of the abutment 1313 and the first base 137 is magnetic, and the other may have opposite magnetism or be metallic, so that the abutment 1313 and the first base 137 attract each other. Specifically, when the first hot end assembly 132 is in the second position, the abutment 1313 and the first base 137 are magnetically attracted, which allows the first hot end assembly 132 to remain stable in the second position, or when the first hot end assembly is still a little short of reaching the second position, the abutment 1313 can provide an attractive force to the first base 137, so that the first base 137 can move into position. In the embodiment provided in this application, during the process of the trigger 1351 colliding with the collision mechanism 16 to move the first hot end assembly 132 from the second position to the first position, the trigger 1351 contacts the contact area of ​​the rod in the collision mechanism 16. Since the position of the contact area is lower than the position of the central axis of the rod. The collision mechanism 16 can apply a downward force to the trigger 1351 to overcome the steady state of the first hot end assembly 132 in the second position and do work, so that the first hot end assembly 132 switches from the second position to the first position.

[0057] The abutment 1313 is magnetic, and the first base 137 is magnetic. The magnetism of the side of the abutment 1313 facing the first base 137 is different from the magnetism of the side of the first base 137 facing the abutment 1313; or, one of the abutment 1313 and the first base 137 is magnetic, and the other is metallic. If one of the abutment 1313 and the first base 137 is metallic, the metal can be iron, iron-containing alloys, nickel, nickel-containing alloys, cobalt, and cobalt-containing alloys, etc.

[0058] Please see Figure 13 and Figure 14 The connecting frame 131a is equipped with a first magnet 1314 and a second magnet 1315, and the second connecting rod 1356 is equipped with a third magnet 13561 or metal. When the first hot end assembly 132 is in the first position, the second magnet 1315 and the third magnet 13561 or metal of the second connecting rod 1356 are magnetically attracted, which can keep the first hot end assembly 132 in a stable state in the first position, so that the first hot end assembly 132 can spray a molten material line in a stable state. When the first hot end assembly is in the second position, the first magnet 1314 and the third magnet 13561 or metal of the second connecting rod 1356 are magnetically attracted, which can keep the first hot end assembly 132 in a stable state in the second position. When the second hot end assembly 133 sprays the molten material line 3, it can prevent the first hot end assembly 132 from descending and interfering with the product, thus affecting the product processing progress.

[0059] In some embodiments, the plug 1358 and the third magnet 13561 are located on opposite sides of the second link 1356, and the third magnet 13561 is closer to the connecting frame 131a in the Z-axis direction than the plug 1358.

[0060] In some embodiments, see Figure 10 The first base 137 connects at least one of the power line 1c and the signal line 1d. The first base 137 is provided with a wire tie 1372 for securing at least one of the power line 1c and the signal line 1d. The wire tie 1372 secures the power line 1c and the signal line 1d, preventing them from tangling. When the first hot-end assembly 132 moves up and down, the power line 1c and the signal line 1d move up and down with the first base 137, preventing the first hot-end assembly 132 from pulling on or damaging the power line 1c or the signal line 1d during the movement.

[0061] In the embodiments provided in this application, please refer to Figure 2 and Figure 15 The 3D printing head 13 also includes an extrusion front shell 139, which is detachably connected to the connecting frame 131.

[0062] Please see Figure 16 and Figure 17 The extrusion front shell 139 includes a first part 1391, a second part 1392, and a third part 1393. The first part 1391 and the second part 1392 are spaced apart along the width direction (e.g., the X-axis direction) of the 3D printing head 13. The third part 1393 connects the first part 1391 and the second part 1392. The first hot end assembly 132 and the second hot end assembly 133 are spaced apart. The first part 1391 and the second part 1392 are located on opposite sides between the first hot end assembly 132 and the second hot end assembly 133. Specifically, the first hot end assembly 132 is located between the first part 1391 and the second part 1392, and the second hot end assembly 133 is located between the first part 1391 and the second part 1392.

[0063] In the depth direction (e.g., the Y-axis direction) of the 3D printing head 13, the first part 1391 and the second part 1392 are located on the same side of the third part 1393. The first part 1391 is provided with a first magnetic suction member 13911 on the side facing away from the third part 1393, and the second part 1392 is provided with a second magnetic suction member 13921 on the side facing away from the third part 1393. The connecting frame 131 is provided with a third magnetic element 1316 and a fourth magnetic element 1317. The first magnetic element 13911 is attracted to the third magnetic element 1316, and the second magnetic element 13921 is attracted to the fourth magnetic element 1317.

[0064] The extrusion front shell 139 is magnetically attached to the connecting frame 131, allowing it to be easily installed on and removed from the connecting frame 131.

[0065] The extrusion front shell 139 is magnetically attached to the connecting frame 131. The magnetic field strength generated by the first magnetic attachment 13911 and the second magnetic attachment 13921 in the extrusion front shell 139 is detected by Hall effect, which can determine whether the extrusion front shell 139 is installed in place (installed to the connecting frame 131).

[0066] The first part 1391 is provided with a first air duct 13912 that runs through the first part 1391 along the height direction (Z-axis direction) of the 3D printing head 13 and has a first air outlet 139122. The second part 1392 is provided with a second air duct 13922 that runs through the second part 1392 along the height direction of the 3D printing head 13 and has a second air outlet 139222. The orientation of the first air outlet 139122 forms a first angle 139121 with the width direction of the 3D printing head 13, and the orientation of the second air outlet 139222 forms a second angle 139221 with the opposite direction of the width direction of the 3D printing head 13. The first angle 139121 and the second angle 139221 are different in size.

[0067] In the embodiments provided in this application, the height position of the first hot-end component 132 when spraying the first material line 2 is different from the height position of the second hot-end component 133 when spraying the second material line 3. Specifically, the height position of the first hot-end component 132 when spraying the molten first material line 2 is a first position, which is lower than the position of the second hot-end component 133. The position of the first hot-end component 132 when the second hot-end component 133 sprays the molten second material line 3 is a second position, which is the highest position that the first hot-end component 132 can rise to under the action of the lifting mechanism 135. The second position is higher than the position of the second hot-end component 133.

[0068] The airflow through the first air duct 13912 can cool the material jet from the first hot end component 132, and the airflow through the second air duct 13922 can cool the material jet from the second hot end component 133, which is conducive to the rapid cooling, solidification and molding of the three-dimensional product.

[0069] In the width direction of the 3D printing head 13, the width direction can be parallel to the X-axis direction. A first hot-end assembly 132 is located between a first part 1391 and a second part 1392, and a second hot-end assembly 133 is located between the first part 1391 and the second part 1392. A first air outlet 139122 sprays molten printing material towards the first hot-end assembly 132, and a second air outlet 139222 sprays molten printing material towards the second hot-end assembly 133. The airflow from the first air outlet 139122 is used to accelerate the cooling of the product formed by the printing material sprayed from the first hot-end assembly 132, and the airflow from the second air outlet 139222 is used to accelerate the cooling of the product formed by the printing material sprayed from the second hot-end assembly 133, thus accelerating product solidification. Specifically, the second air outlet 139222 faces the second nozzle 1331, and when the first hot-end assembly 132 is in the first position, the first air outlet 139122 faces the first nozzle 1322.

[0070] The third part 1393 is provided with a third air duct 13931 that runs through the third part 1393 along the height direction of the 3D printing head 13. The height direction of the 3D printing head 13 is parallel to the Z-axis direction. The third air duct 13931 can also cool the molten printing material ejected from the first nozzle 1322 through the third air duct 13931. The third air duct 13931 can also cool the molten printing material ejected from the second nozzle 1331 through the third air duct 13931. It should be noted that there can be multiple third air ducts 13931, each of which has a third air outlet 139311. Multiple third air ducts 13931 can be arranged along the width direction of the 3D printing head 13.

[0071] Projected along the depth direction of the 3D printing head 13, the depth direction of the 3D printing head 13 is parallel to the Y-axis direction. The third air outlet 139311 is located between the first air outlet 139122 and the second air outlet 139222. The first air outlet 139122, the second air outlet 139222, and the third air outlet 139311 partially surround the first nozzle 1322, which can improve the cooling effect of the first nozzle 1322. The first air outlet 139122, the second air outlet 139222, and the third air outlet 139311 partially surround the second nozzle 1331, which can improve the cooling effect of the second nozzle 1331.

[0072] The extrusion front housing 139 is equipped with a first fan 1394, which is used to input airflow to the first air duct 13912, the second air duct 13922 and the third air duct 13931. The first air duct 13912, the second air duct 13922 and the third air duct 13931 can share one first fan 1394.

[0073] The airflow generated by the first fan 1394 can pass through the first air duct 13912, cooling the molten printing material ejected from the first nozzle 1322. The airflow from the first fan 1394 can also pass through the first air duct 13912, cooling the molten printing material ejected from the second nozzle 1331. The airflow from the first fan 1394 can also pass through the second air duct 13922, cooling the molten printing material ejected from the first nozzle 1322. The airflow from the first fan 1394 can also pass through the third air duct 13931, cooling the molten printing material ejected from the first nozzle 1322. The airflow from the first fan 1394 can also pass through the third air duct 13931, cooling the molten printing material ejected from the second nozzle 1331.

[0074] Specifically, the first fan 1394 is located on the side of the first air duct 13912 away from the first air outlet 139122, the first fan 1394 is located on the side of the second air duct 13922 away from the second air outlet 139222, the third air duct 13931 has a third air outlet 139311, and the first fan 1394 is located on the side of the third air duct 13931 away from the third air outlet 139311.

[0075] Please refer to the 3D printing head 13 provided in this application. Figure 18 The first hot end assembly 132 further includes a first feed channel 1324 and a first heat sink 1325 disposed below or around the first feed channel 1324. A first heating block 1323 is connected between the first feed channel 1324 and the first nozzle 1322. The 3D printing head 13 also includes a second fan 13a, which blows air toward the first heat sink 1325. The first feed channel 1324 is used for the first feed line 2 to pass through and extend into the location of the first heating block 1323. The first heating block 1323 heats the first feed line 2 to a molten state, and the first nozzle 1322 sprays the molten first feed line 2 onto the processing platform. While heating the first feed line 2, the first heating block 1323 also transfers heat to the first feed channel 1324. To prevent the first feed line 2 from softening due to excessive temperature in the first feed channel 1324, the second fan 13a blows air onto the first heat sink 1325, allowing it to quickly dissipate heat and rapidly reduce the temperature of the first feed channel 1324. If the temperature of the first feed channel 1324 becomes too high and prematurely softens the first feed line 2, it will hinder the feeding of the first feed line 2 and easily clog the first feed channel 1324.

[0076] The second hot end assembly 133 also includes a second feed channel 1333 and a second heat sink 1334 disposed below or around the second feed channel 1333. A second heating block 1332 is connected between the second feed channel 1333 and the second nozzle 1331. The 3D printing head 13 also includes a third fan 13b, which blows air toward the second heat sink 1334. The second feed channel 1333 is used for the second feed filament 3 to pass through and extend into the location of the second heating block 1332. The second heating block 1332 heats the second feed filament 3 to a molten state, and the second nozzle 1331 sprays the molten second feed filament 3 onto the processing platform. While heating the second feed line 3, the second heating block 1332 also transfers heat to the second feed channel 1333. To prevent the second feed line 3 from softening prematurely due to excessive temperature in the second feed channel 1333, the second fan 13a blows air onto the second heat sink 1334, allowing it to quickly dissipate heat and rapidly reduce the temperature of the second feed channel 1333. If the temperature of the second feed channel 1333 becomes too high and the second feed line 3 softens prematurely, it will hinder the conveying of the second feed line 3 and easily clog the first feed channel 1324.

[0077] In the embodiments provided in this application, the outer shell 15 surrounds and forms a build space. Specifically, the outer shell 15 may further include a frame, which is connected to the base 151. The 3D printing head 13 and the guide 14 are disposed within the build space. The guide 14 is connected to the outer shell 15, and the first extrusion assembly 11 is detachably disposed on the outer shell 15. The guide 14 is specifically connected to the frame.

[0078] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0079] Furthermore, the use of terms such as "first," "second," etc., in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0080] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0081] Furthermore, the technical solutions of the various embodiments of this application can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this application.

[0082] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An extrusion front shell suitable for a 3D printing head, characterized in that, The 3D printing head includes a connecting frame, a first hot end assembly, and a second hot end assembly. The first hot end assembly and the second hot end assembly are connected to the connecting frame, and at least one of the first hot end assembly and the second hot end assembly is movably connected to the connecting frame. The first hot end assembly is used to spray molten printing material, and the second hot end assembly is used to spray molten printing material. The extrusion front shell is detachably connected to the connecting frame. The extrusion front shell includes a first part, a second part, and a third part. The first part and the second part are spaced apart along the width direction of the 3D printing head. The third part connects the first part and the second part. The first hot end assembly and the second hot end assembly are spaced apart. The first part and the second part are located on opposite sides between the first hot end assembly and the second hot end assembly. The first part is provided with a first air duct that runs through the first part along the height direction of the 3D printing head. The first air duct has a first air outlet. The first air outlet is directed toward the molten printing material ejected from the first hot end component. The second part is provided with a second air duct that runs through the second part along the height direction of the 3D printing head. The second air duct has a second air outlet. The second air outlet is used to spray the molten printing material ejected from the second hot end component. The orientation of the first air outlet forms a first angle with the width direction of the 3D printing head, and the orientation of the second air outlet forms a second angle with the opposite direction of the width direction of the 3D printing head. The first angle and the second angle are different in size.

2. The extruded front shell as described in claim 1, characterized in that, In the depth direction of the 3D printing head, the first part and the second part are located on the same side of the third part. The first part is provided with a first magnetic suction member on the side facing away from the third part, and the second part is provided with a second magnetic suction member on the side facing away from the third part. The connecting frame is provided with a third magnetic component and a fourth magnetic component. The first magnetic component is attracted to the third magnetic component, and the second magnetic component is attracted to the fourth magnetic component.

3. The extrusion front shell as described in claim 1 or 2, characterized in that, The third part is provided with a third air duct that runs through the third part along the height direction of the 3D printing head.

4. The extruded front shell as described in claim 3, characterized in that, The third air duct has a third air outlet, which is located between the first air outlet and the second air outlet in the projection of the 3D printing head in the depth direction.

5. The extruded front shell as described in claim 3, characterized in that, The extrusion front shell is equipped with a first fan, which is used to input airflow into the first air duct, the second air duct and the third air duct.

6. The extruded front shell as described in claim 5, characterized in that, The first fan is located on the side of the first air duct away from the first air outlet, the first fan is located on the side of the second air duct away from the second air outlet, the third air duct has a third air outlet, and the first fan is located on the side of the third air duct away from the third air outlet.

7. A 3D printing head, characterized in that, Includes a connecting frame, a first hot end assembly, a second hot end assembly, and an extrusion front shell as described in any one of claims 1-6; The first hot end assembly and the second hot end assembly are connected to the connecting frame, and at least one of the first hot end assembly and the second hot end assembly is movably connected to the connecting frame; the extrusion front shell is detachably connected to the connecting frame.

8. The 3D printing head as described in claim 7, characterized in that, The first hot end assembly includes a first heating block and a first nozzle. The first heating block is used to heat the first material line to a molten state, and the first nozzle is used to spray the molten first material line. The first air outlet faces the first nozzle. The second hot end assembly includes a second heating block and a second nozzle. The second heating block is used to heat the second material line to a molten state, and the second nozzle is used to spray the molten second material line. The second air outlet faces the second nozzle.

9. The 3D printing head as described in claim 8, characterized in that, It also includes a lifting mechanism, the first hot end component is connected to the connecting frame through the lifting mechanism, the lifting mechanism is used to drive the first hot end component to perform lifting and lowering movements, and the second hot end component is fixedly connected to the connecting frame.

10. The 3D printing head as described in claim 9, characterized in that, The movement trajectory of the first hot end component includes a first position and a second position. The first position is lower than the position of the second hot end component, and the position of the second hot end component is lower than the second position. When the first hot end component is in the first position, the first air outlet faces the first nozzle.

11. The 3D printing head as described in claim 8, characterized in that, The first hot end assembly further includes a first feed channel and a first heat sink disposed around the first feed channel. The first heating block is connected between the first feed channel and the first nozzle. The 3D printing head further includes a second fan that blows air toward the first heat sink.

12. The 3D printing head as described in claim 11, characterized in that, The second hot end assembly also includes a second feed channel and a second heat sink disposed around the second feed channel. The second heating block is connected between the second feed channel and the second nozzle. The 3D printing head also includes a third fan that blows air toward the second heat sink.

13. A 3D printer, characterized in that, The 3D printer includes a 3D print head as described in any one of claims 7-12.

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