A print head for a 3D printer and a 3D printer

Abstract

This application provides a print head for a 3D printer and a 3D printer itself. The print head body includes an extrusion roller, a hot end assembly, and a support located between the extrusion roller and the hot end assembly. The hot end assembly and the support are fixedly connected to the print head body, and the rigidity of the print head body is within a certain range. When the extrusion roller extrudes printing material towards the hot end assembly, the print head body deforms, causing the hot end assembly to displace relative to the support. A distance sensing device is provided on the side of the support facing the hot end assembly. This distance sensing device senses the distance between the hot end assembly and the support to obtain the extrusion force exerted by the printing material on the hot end assembly. Implementing this application can reduce the cost of measuring the extrusion force on the hot end assembly, and it has a simple structure and compact space.

Description

[0001] This application claims priority to Chinese Patent Application No. 202322334305.3, filed on August 28, 2023, entitled “A printhead for a 3D printer and a 3D printer”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of 3D printing technology, and in particular to a print head for a 3D printer and a 3D printer. Background Technology

[0003] In a 3D printer, extrusion rollers force printing material against a hot-end assembly, which in turn exerts an extrusion force on the assembly. The extrusion force acting on the hot-end assembly is related to the printing quality of the 3D printer, so it is necessary to measure this force.

[0004] The existing technology is to use Figure 1 The cantilever surface strain method shown in the figure is used to measure extrusion force, such as Figure 1 As shown, the hot-end assembly 13 is connected to one end of the strain cantilever 15, and the other end of the strain cantilever 15 is fixed. A strain gauge 14 is attached to the surface of the strain cantilever 15. When the extrusion roller 11 presses the printing material 12 onto the hot-end assembly 13, the extrusion force exerted by the printing material 12 on the hot-end assembly 13 is transmitted to the strain cantilever 15, causing strain on the surface of the strain cantilever 15. The strain of the strain cantilever 15 can then be measured using the strain gauge 14, thereby measuring the extrusion force acting on the hot-end assembly 13. Due to the high cost of strain gauges, this existing method of measuring the extrusion force acting on the hot-end assembly is costly. Summary of the Invention

[0005] This application provides a print head for a 3D printer and a 3D printer, which can reduce the cost of measuring the extrusion force on the hot end component, and has a simple structure and compact space.

[0006] In a first aspect, embodiments of this application provide a print head for a 3D printer. The print head body includes an extrusion wheel, a hot end assembly, and a support located between the extrusion wheel and the hot end assembly; wherein...

[0007] The hot end assembly and the bracket are fixedly connected to the print head body, and the rigidity of the print head body is within a certain range; when the extrusion wheel squeezes the printing material toward the hot end assembly, the print head body deforms, causing the hot end assembly to displace relative to the bracket.

[0008] The support has a distance sensing device on the side facing the hot end assembly. The distance sensing device is used to sense the distance between the hot end assembly and the support to obtain the extrusion force exerted by the printing material on the hot end assembly.

[0009] This application embodiment adds a distance sensing device between the support and the hot-end component. The distance sensing device senses the distance between the hot-end component and the support, thereby obtaining the extrusion force exerted by the printing material on the hot-end component (i.e., the extrusion force experienced by the hot-end component). Compared to the cantilever surface strain method in the prior art, the distance sensing device requires lower-cost back-end analog circuitry. Especially in scenarios requiring high sampling rate extrusion force measurement, the cantilever surface strain method is extremely expensive. The distance sensing device in this application embodiment has high bandwidth, making it applicable even with increased sampling rates, and its cost is relatively low. Furthermore, the hot-end component does not rely on a cantilever connection to the upper-level structure, resulting in a simple structure, high design flexibility, and high space utilization.

[0010] In conjunction with the first aspect, in a first possible implementation, the hot end component is used to contact the printing platform of the 3D printer;

[0011] The distance sensing device is also used to sense multiple distances between the hot end assembly and multiple locations in the printing platform to obtain the flatness of the printing platform.

[0012] In this embodiment, the flatness of the printing platform can provide data support for the leveling of the printing platform of the 3D printer. That is, by implementing this embodiment, the extrusion force on the hot end component and the leveling of the printing platform share a single distance sensing device, which can further reduce costs.

[0013] In a second possible implementation, in conjunction with the first aspect or any of the above possible implementations of the first aspect, the distance sensing device includes a coil, the hot end assembly includes heat dissipation fins, and the plane of the coil is parallel to the surface of the heat dissipation fins.

[0014] In this embodiment, a coil is used to sense the distance between the hot-end assembly and the support, which is cost-effective. Furthermore, the plane of the coil is parallel to the surface of the heat sink fins. When the distance between the hot-end assembly and the support changes, the reverse induced current generated by the heat sink fins can significantly affect the magnetic field strength of the coil, thereby improving the accuracy of extrusion force measurement.

[0015] In a third possible implementation, in conjunction with the first aspect or any of the possible implementations described above, the hot-end component includes heat dissipation fins, the distance between the distance sensing device and the heat dissipation fins is less than the sensing distance, and the sensing distance is related to the type of the distance sensing device. Implementing the embodiments of this application can improve the accuracy of measuring extrusion force.

[0016] In a fourth possible implementation, in conjunction with the first aspect or any of the above possible implementations of the first aspect, the distance sensing device includes a coil, and the sensing distance is the diameter of the circumcircle of the coil.

[0017] By implementing the embodiments of this application, the distance between the distance sensing device and the heat sink fins is set to be less than the diameter of the outer circle of the coil, thus avoiding the influence of excessive distance on the measurement and improving the measurement accuracy.

[0018] In a fifth possible implementation, in conjunction with the first aspect or any of the above possible implementations of the first aspect, the distance between the coil and the heat sink fins is less than one-fifth of the sensing distance.

[0019] By implementing the embodiments of this application, the distance between the coil and the heat sink fins can be set to be less than one-fifth of the diameter of the circumcircle of the coil, which can further improve the sensitivity of the distance sensing device and thus improve the accuracy of measuring distance and extrusion force.

[0020] In a sixth possible implementation, in conjunction with the first aspect or any of the above possible implementations of the first aspect, the distance sensing device includes a coil, the hot end assembly includes heat sink fins, and the winding direction of the coil is parallel to the surface of the heat sink fins.

[0021] By implementing the embodiments of this application, the magnetic flux of the magnetic field generated by the coil can significantly affect the heat sink fins, thereby improving the accuracy of measuring extrusion force.

[0022] In a seventh possible implementation, in conjunction with the first aspect or any of the above possible implementations of the first aspect, the distance sensing device includes a coil, the hot end assembly includes heat dissipation fins, and the angle between the plane containing the coil and the surface of the heat dissipation fins is an acute angle.

[0023] Implementing the embodiments of this application can reduce the size of the coil, lower the cost, and reduce the space occupied, while adapting to different application scenarios.

[0024] In an eighth possible implementation, in conjunction with the first aspect or any of the above possible implementations of the first aspect, the distance sensing device includes a coil and the hot end assembly includes heat dissipation fins.

[0025] The printhead is also equipped with a resonant circuit, which is connected to the coil. The resonant circuit is used to output different voltage signals according to the distance between the coil and the heat sink fins.

[0026] By implementing the embodiments of this application, different voltage signals are output by a resonant circuit, and the distance between the hot end component and the coil is obtained based on the voltage signals, thereby obtaining the extrusion force exerted by the printing material on the hot end component.

[0027] In a ninth possible implementation, in conjunction with the first aspect or any of the above possible implementations of the first aspect, the distance sensing device includes a coil and the hot end assembly includes heat dissipation fins.

[0028] The printhead is also equipped with a coil detection circuit, which is connected to the coil and is used to measure the inductance and resistance of the coil based on the distance between the coil and the heat sink fins.

[0029] By implementing the embodiments of this application, the inductance and resistance of the coil are measured using a coil detection circuit. The distance between the hot end assembly and the coil can then be determined based on the inductance and resistance of the coil, thereby obtaining the extrusion force exerted by the printing material on the hot end assembly.

[0030] Secondly, embodiments of this application provide a 3D printer, the 3D printer including a printing platform and a print head as described above in conjunction with the first aspect or any possible implementation; wherein the print head is used to extrude printing material on the printing platform.

[0031] It should be understood that the implementations and beneficial effects of the above-mentioned aspects of this application can be referenced from each other. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of a printhead for a 3D printer provided by existing technology;

[0033] Figure 2 This is a schematic diagram of the structure of a 3D printer provided in an embodiment of this application;

[0034] Figure 3 A schematic diagram of the structure of a printhead provided in an embodiment of this application;

[0035] Figure 4 This is a schematic diagram showing the relative position between the hot-end assembly and the coil provided in an embodiment of this application;

[0036] Figure 5 Another schematic diagram showing the relative position between the hot-end assembly and the coil provided in an embodiment of this application;

[0037] Figure 6 A schematic diagram of the circumcircle of a coil provided in an embodiment of this application;

[0038] Figure 7 A circuit diagram of a resonant circuit provided in an embodiment of this application. Detailed Implementation

[0039] The implementation of the technical solution of this application will be further described in detail below with reference to the accompanying drawings.

[0040] See Figure 2 , Figure 2 This is a schematic diagram of the structure of a 3D printer provided in an embodiment of this application. Figure 2 As shown, the 3D printer 102 is connected to the feeding device 101.

[0041] The feeding device 101 can suspend a material tray on which printing material is wound. The feeding device 101 can supply printing material to the 3D printer 102, or the printing material can be rewound back to the material tray via the feeding device. That is, the feeding device can feed or unload material.

[0042] The 3D printer 102 includes a print head 1021, wherein the print head 1021 includes a feeding unit 10211, a hot end assembly 10212, and an extrusion roller disposed between the feeding unit 10211 and the hot end assembly 10212. During the feeding process of the feeding device 101, the printing material enters the extrusion roller after passing through the feeding unit 10211, and the extrusion roller supplies the printing material to the hot end assembly 10212; during the unloading process of the feeding device 101, the 3D printer 102 cuts the printing material in the print head 1021, and the extrusion roller conveys the printing material back to the feeding device 101.

[0043] Optionally, the 3D printer 102 may cut the printing material between the extrusion wheel and the hot end assembly 10212 or in the extrusion wheel. This application does not limit the location where the 3D printer cuts the printing material.

[0044] For example, the 3D printer 102 also includes a printing platform, a base 1025, and a slider 1029. The printing platform may include at least one of a printing panel 1023 and a heated bed 1024. The heated bed 1024 is located on the side of the base 1025a facing the hot end assembly 10212 and has a heating function. The printing panel 1023 is located on the side of the heated bed 1024 facing the hot end assembly 10212. Heat from the heated bed 1024 can be conducted to the printing panel 1023, and the hot end assembly 10212 can extrude molten printing material onto the printing panel 1023.

[0045] In its implementation, the 3D printer can adjust the temperatures of the hot-end assembly 10212 and the heated bed 1024. The temperature of the hot-end assembly 10212 is adjusted to heat the printing material to a molten state, and the temperature of the heated bed 1024 is adjusted to adhere the printing material extruded from the hot-end assembly 10212 onto the printing panel 1023. The print head 1021 is slidably connected to the first guide rail 1026, and can move along the length of the first guide rail 1026, thus achieving displacement of the print head 1021 relative to the printing panel 1023 along the length of the first guide rail 1026. The heated bed 1024 is slidably connected to the second guide rail 1027, and the heated bed 1024 moves along the length of the second guide rail 1027, which is perpendicular to the length of the first guide rail 1026. Furthermore, the first guide rail 1026 is slidably connected to the third guide rail 1028. By moving the first guide rail 1026 along the third guide rail 1028, the 3D printer 102 can achieve displacement of the print head 1021 relative to the print panel 1023 in both directions perpendicular to the length of the second guide rail 1027 and perpendicular to the length of the first guide rail 1026. In other words, the 3D printer 102 can achieve three mutually perpendicular printing paths to print a three-dimensional object.

[0046] In this embodiment of the application, a distance sensing device is added between the support and the hot end assembly. This distance sensing device can sense the distance between the hot end assembly and the support to obtain the extrusion force exerted by the printing material on the hot end assembly.

[0047] refer to Figure 3 , Figure 3 This is a schematic diagram of the structure of a printhead provided in an embodiment of this application. Figure 3 As shown, the printhead body 200 is provided with an extrusion wheel 201, a hot end assembly 202, and a support 203 located between the extrusion wheel 201 and the hot end assembly 202.

[0048] The hot-end assembly 202 may include heat dissipation fins 2021, a nozzle 2023, and a heating unit. The heating unit can be used to heat the printing material, which is then molten and extruded through the nozzle 2023. For example, the heat dissipation fins 2021 can dissipate the heat conducted by the heating unit in the hot-end assembly 202, preventing the printing material from becoming molten before passing through the heating unit. The heat dissipation fins 2021 can be made of a metal material such as aluminum or iron.

[0049] Optionally, the hot end assembly 202 may also include a silicone sleeve 2022, which is disposed around the heating unit to prevent heat loss from the heating unit and to prevent the user from being burned when accidentally touching the hot end assembly.

[0050] The hot-end assembly 202 and the bracket 203 can be fixedly connected to the printhead body 200. Optionally, the printhead body 200 may include a printhead bracket 206 and an extrusion back cover 207. The printhead bracket 206 can be fixedly connected to the extrusion back cover 207 and the hot-end assembly 202. Specifically, the hot-end assembly 202 can be fixedly connected to a base, which is connected to the printhead bracket 206 via a fixed shaft. The connections involved in this application include detachable connections and non-detachable connections; for example, fixed connections may include detachable fixed connections and non-detachable fixed connections. The extrusion back cover 207 is fixedly connected to the bracket 203, that is, the bracket 203 is connected to the printhead bracket 206 through the extrusion back cover 207. Exemplarily, the extrusion back cover 207 and the bracket 203 can be integrally formed.

[0051] The stiffness of the printhead body 200 is within a certain range. Stiffness refers to the ability of a material or structure to resist elastic deformation when subjected to force; that is, the printhead body 200 is not completely rigid. When the extrusion roller 201 pushes the printing material towards the hot-end assembly 202, the nozzle 2023 in the hot-end assembly 202 is subjected to extrusion force, causing the heat sink fins 2021 to move away from the extrusion roller 201, thus changing the distance between the hot-end assembly 202 and the support 203.

[0052] In a specific implementation, the support 203 has a distance sensing device 204 on the side facing the hot-end assembly 202, that is, the distance sensing device 204 is located between the support 203 and the hot-end assembly 202. The distance sensing device 204 can be used to sense the distance between the hot-end assembly 202 and the support 203. The distance between the hot-end assembly 202 and the support 203 is related to the extrusion force exerted by the printing material on the hot-end assembly. Therefore, after obtaining the distance between the hot-end assembly 202 and the support 203, the extrusion force exerted by the printing material on the hot-end assembly 202 can be obtained by converting the distance to the extrusion force, which is the extrusion force experienced by the nozzle 2023.

[0053] This application embodiment adds a distance sensing device between the support and the hot-end component. The distance sensing device senses the distance between the hot-end component and the support, thereby obtaining the extrusion force exerted by the printing material on the hot-end component (i.e., the extrusion force experienced by the hot-end component). Compared to the cantilever surface strain method in the prior art, the distance sensing device requires lower-cost back-end analog circuitry. Especially in scenarios requiring high sampling rate extrusion force measurement, the cantilever surface strain method is extremely expensive. The distance sensing device in this application embodiment has high bandwidth, making it applicable even with increased sampling rates, and its cost is relatively low. Furthermore, the hot-end component does not rely on a cantilever connection to the upper-level structure, resulting in a simple structure, high design flexibility, and high space utilization.

[0054] In some feasible implementations, the distance sensing device 204 may include a coil. When the distance between the hot-end assembly 202 and the support 203 changes, the distance between the hot-end assembly 202 and the coil also changes, causing a change in the equivalent inductance of the coil. For example, when the distance between the hot-end assembly 202 and the coil increases, the equivalent inductance of the coil decreases. The distance between the hot-end assembly 202 and the coil can then be calculated by measuring the equivalent inductance of the coil, thereby obtaining the extrusion force exerted by the printing material on the hot-end assembly 202. In this case, by using only one coil to measure the extrusion force, the space and material costs required for extrusion force measurement are reduced. Furthermore, since the coil does not have a filtering circuit, the measurement bandwidth, sampling rate, and refresh rate of coil ranging are high, making it suitable for high sampling rate scenarios and improving the accuracy of extrusion force measurement.

[0055] Optionally, the inductance of the coil can be 20μH. The inductance of the coil is related to the self-induction capability of the inductor. A better inductance can improve the ability to sense changes in distance.

[0056] The distance sensing device 204 senses the distance between the hot-end assembly 202 and the bracket 203, specifically the distance between the heat sink 2021 in the hot-end assembly 202 and the bracket 203. If the distance sensing device 204 includes a coil, it specifically senses the distance between the heat sink 2021 in the hot-end assembly 202 and the coil on the bracket 203.

[0057] Furthermore, in some feasible implementations, see [link to relevant documentation]. Figure 4 , Figure 4 This is a schematic diagram showing the relative position between the hot-end assembly and the coil provided in an embodiment of this application. Figure 4 As shown, the plane containing coil 3041 is parallel to the surface of heat sink 3021. In specific implementation, when the distance between the hot-end component and the bracket decreases, due to the oscillating current within coil 3041, Lenz's law indicates that heat sink 3021 will generate a reverse induced current. This reverse induced current reduces the magnetic flux through coil 3041, meaning the equivalent inductance of coil 3041 decreases, and the resonant frequency of coil 3041 increases. Conversely, when the distance between the hot-end component and the bracket increases, the reverse induced current generated by heat sink 3021 increases the magnetic flux through coil 3041, meaning the equivalent inductance of coil 3041 increases, and the resonant frequency of coil 3041 decreases. Therefore, there is a correlation between the distance between the hot-end component and the bracket and the resonant frequency of coil 3041. When the plane of coil 3041 is parallel to the surface of heat sink 3021, the reverse magnetic field corresponding to the reverse induced current generated by heat sink 3021 is perpendicular to the plane of coil 3041. The number of magnetic flux lines in this reverse magnetic field passing through the coil is large, and the sensitivity of the coil sensing is high, thereby improving the accuracy of measuring extrusion force.

[0058] Optionally, in some feasible embodiments, the winding direction of coil 3041 is parallel to the surface of heat sink fin 3021. In this case, the magnetic flux of the magnetic field generated by the coil can significantly affect the heat sink fin, thereby improving the accuracy of extrusion force measurement.

[0059] Optionally, in some feasible implementations, Figure 5 This is another schematic diagram showing the relative position between the hot-end assembly and the coil provided in an embodiment of this application. (See diagram below.) Figure 5 As shown, the angle between the plane containing coil 4041 and the surface of heat sink 4021 can be an acute angle. This allows for more flexible placement of coil 4041, making it suitable for a wider range of applications.

[0060] In some feasible implementations, the distance between the distance sensor and the heat sink fins can be less than the sensing distance, which may be related to the type of distance sensor. If the plane containing the distance sensor forms an acute angle with the heat sink fins, then the distance between the distance sensor and the heat sink fins can be the maximum distance between them. Since different types of distance sensors have different sensing distances, setting the distance between the distance sensor and the heat sink fins to be less than the sensing distance ensures that the distance sensor can perform its measurement function and avoids situations where the distance is too far and the distance sensor cannot perform measurements.

[0061] For example, the distance sensing device can be an eddy current sensor, and the distance sensing device can include a coil, in which case the sensing distance can be the diameter of the circumcircle of the coil. Figure 6 As shown, taking a square coil as an example, assuming the coil size is 10mm*10mm, the diameter of the coil's circumcircle is...

[0062] In some feasible implementations, the distance between the coil and the heat sink fins can be less than one-fifth of the sensing distance. For example, the distance between the coil and the heat sink fins is less than one-fifth of the diameter of the coil's circumscribed circle. The inventors of this application have found in practice that setting the distance between the coil and the heat sink fins to less than one-fifth of the diameter of the coil's circumscribed circle results in higher sensitivity and better accuracy in measuring extrusion force.

[0063] In some feasible implementations, see Figure 7 , Figure 7 A circuit diagram of a resonant circuit provided in an embodiment of this application. (See diagram below.) Figure 7 As shown, the printhead also has a resonant circuit connected to a coil. Since the equivalent inductance of the coil changes with the distance between the hot-end assembly and the support, the resonant circuit outputs voltage signals at different frequencies.

[0064] In a specific implementation, the resonant circuit may include a first capacitor C1, a second capacitor C2, a third capacitor C3, a first resistor R1, a second resistor R2, and a third resistor R3, wherein the first capacitor C1 and the second capacitor C2 are resonant capacitors. For example, by adjusting the capacitance values ​​of the first capacitor C1 and the second capacitor C2 to set the resonant frequency to approximately 1MHz, a voltage signal with an oscillation frequency of approximately 1MHz can be output at the Out+ terminal. This oscillation frequency varies with the distance between the coil and the heat sink fins. By connecting the Out+ connector to a controller with frequency measurement capabilities, the oscillation frequency can be digitally input into the controller's program. Through the controller's calculations, the distance between the hot-end component and the support can be obtained, and the extrusion force exerted by the printing material on the hot-end component can be obtained through the conversion of distance and extrusion force.

[0065] In this embodiment, by using a resonant circuit to output different voltage signals, and then obtaining the distance between the hot end component and the coil based on the voltage signals, the extrusion force exerted by the printing material on the hot end component can be obtained, thus realizing the distance sensing process.

[0066] Optionally, in some feasible implementations, the printhead may also be equipped with a coil detection circuit connected to a coil. Since the equivalent inductance of the coil changes with the distance between the hot-end assembly and the support, that is, the inductance and resistance of the coil also change with the distance between the hot-end assembly and the support. Therefore, the coil detection circuit can convert the inductance and resistance values ​​of the coil into an analog voltage signal. The controller acquires this analog voltage signal to obtain the inductance and resistance values ​​of the coil, and based on the inductance and resistance values ​​of the coil, the distance between the hot-end assembly and the support can be determined.

[0067] In this embodiment, a coil detection circuit is used to measure the inductance and resistance of the coil. The distance between the hot end component and the coil can then be determined based on the inductance and resistance of the coil. This allows the extrusion force exerted by the printing material on the hot end component to be obtained, thus realizing the distance sensing process.

[0068] Optionally, in some feasible implementations, the nozzle in the hot end assembly can contact the printing platform of the 3D printer, and the distance sensing device is also used to sense multiple distances between the hot end assembly and multiple locations in the printing platform to obtain the flatness of the printing platform.

[0069] For example, the print head can also be equipped with a leveling detection circuit, which can be connected to a distance sensing device. This distance sensing device can output different signals according to the change in distance between the coil and the heat sink fins, thereby obtaining the flatness of the printing platform.

[0070] In one example, the distance sensing device is a coil, and the leveling detection circuit can be connected in parallel with the extrusion force detection circuit (such as the resonant circuit and coil detection circuit mentioned above). The leveling detection circuit can also share the same circuit with the extrusion force detection circuit.

[0071] In this embodiment, the flatness of the printing platform can provide data support for the leveling of the printing platform of the 3D printer. That is, by implementing this embodiment, the extrusion force on the hot end component and the leveling of the printing platform share a single distance sensing device, which can further reduce costs.

[0072] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

Claims

1. A print head for a 3D printer, characterized in that, The printhead body includes an extrusion roller, a hot end assembly, and a support located between the extrusion roller and the hot end assembly; wherein... The hot end assembly and the bracket are fixedly connected to the printhead body, and the rigidity of the printhead body is within a certain range. The bracket has a distance sensing device on the side facing the hot end assembly.

2. The printhead according to claim 1, characterized in that, The hot end assembly is used to contact the printing platform of the 3D printer; The distance sensing device is also used to sense multiple distances between the hot end assembly and multiple locations in the printing platform to obtain the flatness of the printing platform.

3. The printhead according to claim 1, characterized in that, The distance sensing device includes a coil, the hot end assembly includes heat dissipation fins, and the plane of the coil is parallel to the surface of the heat dissipation fins.

4. The printhead according to claim 1, characterized in that, The hot end component includes heat dissipation fins, and the distance between the distance sensing device and the heat dissipation fins is less than the sensing distance, which is related to the type of the distance sensing device.

5. The printhead according to claim 4, characterized in that, The distance sensing device includes a coil, and the sensing distance is the diameter of the circumcircle of the coil.

6. The printhead according to claim 5, characterized in that, The distance between the coil and the heat sink fins is less than one-fifth of the sensing distance.

7. The printhead according to any one of claims 1 to 6, characterized in that, The distance sensing device includes a coil, the hot end assembly includes heat sink fins, and the winding direction of the coil is parallel to the surface of the heat sink fins.

8. The printhead according to claim 1, characterized in that, The distance sensing device includes a coil, the hot end assembly includes heat dissipation fins, and the angle between the plane where the coil is located and the surface of the heat dissipation fins is an acute angle.

9. The printhead according to any one of claims 1 to 6, characterized in that, The distance sensing device includes a coil, and the hot end assembly includes heat dissipation fins; The printhead is also equipped with a resonant circuit, which is connected to the coil. The resonant circuit is used to output different voltage signals according to the distance between the coil and the heat sink fins.

10. The printhead according to any one of claims 1 to 6, characterized in that, The distance sensing device includes a coil, and the hot end assembly includes heat dissipation fins; The printhead is also equipped with a coil detection circuit, which is connected to the coil and is used to measure the inductance and resistance of the coil based on the distance between the coil and the heat sink fins.

11. The printhead according to any one of claims 1 to 6, characterized in that, The distance sensing device is used to sense the distance between the hot end assembly and the support to obtain the extrusion force exerted by the printing material on the hot end assembly.

12. A 3D printer, characterized in that, The 3D printer includes a printing platform and a print head as described in any one of claims 1 to 11; wherein the print head is used to extrude printing material on the printing platform.

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