Strain sensor, print head, and 3D printer

Abstract

A strain sensor (100), a print head (200), and a 3D printer (300). The strain sensor (100) comprises an elastic connecting member (10) and a detection member (20). The elastic connecting member (10) comprises a connecting portion (11) and a fixing portion (12) spaced apart from each other in the length direction of the elastic connecting member (10); first grooves (13) are inwardly recessed and formed in the width direction of the elastic connecting member (10) in two opposite sides of the middle of the connecting portion (11); and the first grooves (13) are used for enhancing the elastic deformation capability of the connecting portion (11). The detection member (20) is attached to the middle of the surface of a side of the connecting portion (11), and the detection member (20) is used for detecting deformation generated by the elastic connecting member (10). The elastic connecting member (10) is further provided with an amplifying hole (14) between the detection member (20) and the fixing portion (12).

Description

Strain sensor, print head and 3D printer

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese Patent Application No. 202323335214.8 filed on December 6, 2023, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present application relates to the field of 3D printing technology, and in particular to a strain sensor, a print head and a 3D printer. Background Art

[0004] 3D printers construct objects by printing layer by layer. During the printing process, the first layer must be kept level. If the plane is not level, the difference is compensated by recording the distance between the print head and the plane to complete the leveling of the printing surface.

[0005] The leveling function of conventional 3D printer printheads is primarily achieved by moving the printhead up and down until it contacts the print platform, with sensors detecting when the printhead contacts the print platform. However, in actual operation, the sensors in conventional 3D printer printheads have low detection sensitivity, resulting in low leveling accuracy. Furthermore, the printhead exerts a large force on the print platform, causing significant deformation and potentially damaging the print platform.

[0006] Summary of the Invention

[0007] The present application provides a strain sensor, a print head and a 3D printer to solve the technical problem of low detection sensitivity of some known strain sensors.

[0008] The embodiment of the present application is implemented as follows:

[0009] In a first aspect, the present application provides a strain sensor comprising an elastic connector and a detection member. The elastic connector has a connecting portion and a fixing portion spaced apart along its length, and a first groove is formed inwardly on opposite sides of the middle portion of the connecting portion and on both sides along the width direction of the elastic connector. The first groove is used to guide the elastic connector to deform at the first groove when the connecting portion is subjected to force and the fixing portion is fixed. The detection member is attached to the middle of one side surface of the connecting portion, and the detection member is used to detect the deformation generated by the elastic connector. The elastic connector is also provided with an enlarged hole between the detection member and the fixing portion.

[0010] The strain sensor of the present application is provided with a first groove formed inwardly on both sides of the elastic connector along its width direction, so that the width of the elastic connector at the first groove is smaller. When the nozzle assembly abuts the printing platform, the connecting portion is subjected to the force from the printing platform, and the fixed portion remains fixed. The elastic connector is more likely to bend at the position with a smaller width, that is, the position where the first groove is provided, thereby driving the detection member at the first groove to deform, thereby ensuring that the detection member can detect the deformation of the elastic connector at this position. The force required for the elastic connector with the first groove to deform is smaller than the force required for the elastic connector without the first groove to produce the same deformation. In this way, the detection sensitivity of the pressure sensor can be improved. Similarly, after the amplification hole is provided between the detection member and the connecting portion, since the elastic connector is hollowed out at this position, the deformation of the elastic connector after the connecting portion is subjected to the same force is greater than the deformation of the elastic connector without the amplification hole. Therefore, the amplification hole can also achieve the purpose of increasing the deformation of the elastic connector and improving the detection sensitivity of the strain sensor.

[0011] In one possible implementation:

[0012] The two first grooves are symmetrically arranged along the width direction of the elastic connecting member, the two first grooves are symmetrical about the first symmetry axis, and the edge of the detection member does not exceed the edge of the first groove.

[0013] In one possible implementation:

[0014] The detection member includes a strain gauge, which includes a first part and a second part. The first part and the second part are symmetrical about a second symmetry axis. The second symmetry axis is parallel to the width direction of the elastic connecting member and is located between two oppositely arranged groove sides of the first groove.

[0015] In one possible implementation:

[0016] The connecting portion is provided with a second groove, which is formed inwardly from the middle of the edge of one side of the connecting portion away from the fixing portion along the length direction of the elastic connecting member. The second groove is used to guide the elastic connecting member to deform at the second groove when it bends from one side to the other side in its width direction.

[0017] In one possible implementation:

[0018] The groove surface of the second groove is further provided with a protruding support portion, and a part of the detection member is attached to the support portion.

[0019] In one possible implementation:

[0020] The distance between the first groove and the connecting portion is L1, the distance between the first groove and the fixing portion is L2, and L2 / L1 is between 4 and 7.

[0021] In a second aspect, the present application provides a print head for extruding consumables onto a printing platform, the print head comprising a bracket, a nozzle assembly, and the aforementioned strain sensor. The bracket is connected to a transfer device. The nozzle assembly is used to extrude consumables. The fixed portion of the strain sensor is connected to the bracket, and the connecting portion of the strain sensor is connected to the nozzle assembly. The strain sensor is configured to be triggered when the nozzle assembly abuts the printing platform.

[0022] In one possible implementation:

[0023] The print head further includes an adapter, one end of which is connected to the connecting portion, and the other end of which is connected to the nozzle assembly.

[0024] In one possible implementation:

[0025] The nozzle assembly includes a heat sink, a side surface of the adapter abuts against and is connected to the heat sink, and the connecting portion is attached to a bottom surface of the adapter and is connected to the heat sink.

[0026] In a third aspect, the present application provides a 3D printer comprising a printing platform, the aforementioned print head, and a transfer device. The transfer device is connected to the print head and is used to drive the print head to move relative to the printing platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0028] FIG1 is a schematic structural diagram of a 3D printer according to one or more embodiments of the present application;

[0029] FIG2 is an exploded side view of a print head according to one or more embodiments of the present application;

[0030] FIG3 is a schematic structural diagram of a print head according to one or more embodiments of the present application;

[0031] FIG4 is a schematic diagram of an exploded structure of a print head according to one or more embodiments of the present application;

[0032] FIG5 is a schematic structural diagram of a strain sensor according to one or more embodiments of the present application;

[0033] FIG6 is a bottom view of a strain sensor according to one or more embodiments of the present application;

[0034] FIG. 7 is a top view of a strain sensor according to one or more embodiments of the present application.

[0035] Description of main component symbols: DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0037] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may also be an element centered therein. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may also be an element centered therein. When an element is considered to be "set on" another element, it may be directly set on the other element or there may also be an element centered therein. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "or / and" as used herein includes any and all combinations of one or more of the relevant listed items.

[0039] Some embodiments of the present application are described in detail. In the absence of conflict, the following embodiments and features of the embodiments can be combined with each other.

[0040] 3D printers construct objects by printing layer by layer. During the printing process, the first layer must be kept level. If the plane is not level, the difference is compensated by recording the distance between the print head and the plane to complete the leveling of the printing surface.

[0041] The leveling function of conventional 3D printer printheads is primarily achieved by moving the printhead up and down until it contacts the print platform, with sensors detecting when the printhead contacts the print platform. However, in actual operation, the sensors in conventional 3D printer printheads have low detection sensitivity, resulting in low leveling accuracy. Furthermore, the printhead exerts a large force on the print platform, causing significant deformation and potentially damaging the print platform.

[0042] In view of this, as shown in FIG1 , an embodiment of the present application provides a 3D printer 300 , wherein the strain sensor 100 has high sensitivity and can improve the leveling accuracy of the 3D printer 300 .

[0043] 1 , this embodiment provides a 3D printer 300 , including a printing platform 301 , a print head 200 , and a transfer device 302 . The print head 200 is used to extrude consumables onto the printing platform 301 .

[0044] The transfer device 302 is connected to the print head 200 and is used to drive the print head 200 relative to the printing platform 301. The transfer device 302 can be implemented as a lead screw motor linear module, a pneumatic cylinder, an electric push rod, etc. For example, the transfer device 302 can be implemented as an X-axis and Z-axis linear module to drive the print head 200 to move horizontally and vertically relative to the printing platform 301. In other embodiments, the transfer device 302 can also be implemented as a multi-axis robot, etc.

[0045] 2 to 4 , the print head 200 includes a bracket 201, a nozzle assembly 202, and a strain sensor 100. The bracket 201 is connected to the transfer device 302. The nozzle assembly 202 is used to eject consumables. The strain sensor 100 includes an elastic connector 10, which includes a connecting portion 11 and a fixing portion 12 spaced apart along its length. The fixing portion 12 is connected to the bracket 201, and the connecting portion 11 of the strain sensor 100 is connected to the nozzle assembly 202. The strain sensor 100 is used to be triggered when the nozzle assembly 202 abuts the printing platform 301.

[0046] Optionally, referring to Figures 2 and 3, the bracket 201 is provided with an axial hole 2011 and a mounting hole 2012, and the transfer device 302 includes an optical axis, a synchronous belt and a driving member (not shown), the synchronous belt is arranged in the mounting hole 2012 and is connected to the bracket 201, the driving member drives the synchronous belt to move to drive the bracket 201 to move, the optical axis is fitted in the axial hole 2011, and is used to guide the movement of the bracket 201.

[0047] Before the 3D printer 300 prints, the transfer device 302 drives the nozzle assembly 202 toward the printing platform 301 through the bracket 201. When the nozzle assembly 202 abuts the printing platform 301, the nozzle assembly 202 is subjected to slight resistance. At this time, the end of the strain sensor 100 connected to the nozzle assembly 202 is subjected to force, and the end of the strain sensor 100 connected to the bracket 201 is fixed. In this way, the strain sensor 100 is deformed. After the strain sensor 100 is deformed, it can generate corresponding detection information (for example, detecting current changes, resistance changes or voltage changes), thereby triggering detection. Therefore, the current position information of the print head 200 can be detected by the strain sensor 100 to facilitate the leveling of the printing platform 301 (for example, the height error of the printing platform 301 can be automatically compensated by software during the actual printing process. The specific compensation algorithm of the software can be based on a known compensation algorithm and will not be repeated here).

[0048] In this embodiment, the nozzle assembly 202 abutting the printing platform 301 means that the nozzle assembly 202 just touches the printing platform 301, rather than squeezing the printing platform 301, and the printing platform 301 does not undergo obvious deformation due to the contact of the nozzle assembly 202; it can be understood that at this time, the printing platform 301 undergoes microscopic deformation, and it can be considered that the printing platform 301 hardly moves in the vertical direction. In this way, after the nozzle assembly 202 abuts the printing platform 301, there is no need to additionally calculate the displacement of the printing platform 301, and the height value of the contact position between the printing platform 301 and the nozzle assembly 202 can be obtained based on the obtained position of the nozzle assembly 202.

[0049] 5 to 7 , the strain sensor 100 includes an elastic connector 10 and a detection member 20. The fixing portion 12 is connected to the bracket 201, and the connecting portion 11 is connected to the nozzle assembly 202. A first groove 13 is formed on opposite sides of the middle portion of the connecting portion 11 and is concave inwardly along the width direction Y2 of the elastic connector 10. The first groove 13 is used to enhance the elastic deformation ability of the connecting portion 11. The detection member 20 is attached to the middle of one side surface of the connecting portion 11, and its edge does not exceed the edge of the first groove 13. The detection member 20 is used to detect the deformation generated by the elastic connector 10. The elastic connector 10 is also provided with an enlarged hole 14 between the detection member 20 and the fixing portion 12.

[0050] By providing a first concave groove 13 on both sides of the connecting portion 11 along the width direction Y2 of the elastic connecting member 10, the width of the connecting portion 11 at the first groove 13 is smaller. When the nozzle assembly 202 abuts the printing platform 301, the connecting portion 11 is subjected to the force from the printing platform 301, and the fixing portion 12 remains fixed. The connecting portion 11 is more likely to bend at a position with a smaller width, that is, where the first groove 13 is provided, thereby driving the detection member 20 at the first groove 13 to deform, thereby ensuring that the detection member 20 can detect the deformation of the connecting portion 11 at this location. The force required for the elastic connecting member 10 with the first groove 13 to deform is smaller than the force required for the elastic connecting member 10 without the first groove 13 to produce the same deformation. In this way, the detection sensitivity of the strain sensor 100 can be improved. Similarly, after the amplifying hole 14 is provided between the detection member 20 and the fixing portion 12, since the elastic connecting member 10 is hollowed out at this location, the deformation of the connecting member 11 after being subjected to the same force is greater than that of the elastic connecting member 10 without the amplifying hole 14. Therefore, the amplifying hole 14 can also increase the deformation of the elastic connecting member 10. In addition, the provision of the two first grooves 13 and the amplifying hole 14 ensures that when the connecting member 11 is subjected to force, the probability of deformation of the portion of the connecting member 11 between the first groove 13 and the amplifying hole 14 is much greater than the probability of deformation of the portion of the connecting member 11 between the amplifying hole 14 and the fixing portion 12. This greatly increases the ability of the detection member 20 to detect deformation of the connecting member 11, thereby improving the detection sensitivity of the strain sensor 100.

[0051] In summary, because the strain sensor 100 of this embodiment is provided with the first groove 13 and the amplifying hole 14, when the connecting portion 11 is subjected to the same force, the elastic connector 10 of this embodiment produces a greater deformation than the elastic connector 10 without the first groove 13 and the amplifying hole 14. When the nozzle assembly 202 slightly contacts the printing platform 301, the strain sensor 100 can generate a trigger signal, thereby significantly improving the sensitivity and accuracy of detecting contact between the nozzle assembly 202 and the printing platform 301. Furthermore, because the nozzle assembly 202 does not need to apply excessive force to the printing platform 301, the deformation of the printing platform 301 during the leveling process can be reduced. This not only reduces the possibility of deformation of the printing platform 301 and improves the protection of the printing platform 301, but also reduces the error caused by the deformation of the printing platform 301, further improving the leveling accuracy of the printing platform 301.

[0052] In this embodiment, the elastic connector 10 is a square elastic sheet, with the connecting portion 11 and the fixing portion 12 located at opposite ends of the square sheet. Alternatively, in this embodiment, the elastic connector 10 can be formed as a spring steel plate. In other embodiments, the fixing portion 12 can be located in the middle of the square sheet. Furthermore, the elastic connector 10 can also be shaped like a racetrack, an ellipse, or other shapes.

[0053] In this embodiment, referring to FIG6 , the distance between the first groove 13 and the connecting portion 11 is L1, the distance between the first groove 13 and the fixing portion 12 is L2, and L2 / L1 is between 4 and 7. L2 / L1 can be specifically set to any one of 4, 4.1, 4.5, 4.9, 5, 5.1, 5.5, 5.9, 6, 6.1, 6.5, 6.9, and 7. In other embodiments, the value of L2 / L1 can also be adjusted according to actual strain detection requirements.

[0054] When the value of L2 / L1 is low, the elastic connector 10 requires a greater force to deform. When the value of L2 / L1 is high, the elastic connector 10 is more likely to deform under the weight of the nozzle assembly 202, affecting subsequent detection. Therefore, in this embodiment, by setting L2 / L1 between 4 and 7, it is possible to ensure that the elastic connector 10 only requires a small amount of force to deform and prevent the elastic connector 10 from failing under the weight of the nozzle assembly 202. Specifically, L2 / L1 can be set to one or more of 4, 4.5, 5, 5.5, 6, 6.5, 7, etc.

[0055] In this embodiment, referring to FIG5 , the enlarged hole 14 is located between the first groove 13 and the fixing portion 12 along the length direction Y1 of the elastic connector 10, and between the two first grooves 13 along the width direction Y2 of the elastic connector 10. The projection of one side of the enlarged hole 14 onto the detection member 20 is located at the edge of the detection member 20. This ensures that the detection member 20 is fully attached to the elastic connector 10, reducing the possibility of the detection member 20 separating from the elastic connector 10 when bent.

[0056] Optionally, referring to Figure 5, the enlarged hole 14 is roughly triangular, with one vertex of the triangle set toward the fixing portion 12, and the other two vertexes set toward both sides of the width direction Y2 of the elastic connector 10. In this way, the size of the enlarged hole 14 increases in the direction close to the connecting portion 11, which can further improve the elastic deformation ability of the elastic connector 10.

[0057] Referring to FIG. 6 , in this embodiment, the connecting portion 11 is provided with a second groove 15 that is concave toward the fixing portion 12. The second groove 15 is used to guide the elastic connector 10 to deform at the second groove 15 when it bends from one side of its width direction Y2 to the other. Because the surface flatness of the printing platform 301 is not clear, there is a possibility that the elastic connector 10 will bend from one side of its width direction Y2 to the other side after the nozzle assembly 202 abuts the printing platform 301. By providing the second groove 15 on the connecting portion 11, the deformation of the elastic connector 10 at the second groove 15 in this situation is greater, which can also improve the detection sensitivity of the strain sensor 100 and enhance the protection of the printing platform 301.

[0058] In addition, the second groove 15 , the enlarged hole 14 and the two first grooves 13 together define an area, which greatly increases the possibility of deformation of the connecting portion 11 in the area when subjected to force, thereby improving the detection sensitivity of the strain sensor 100 .

[0059] In this embodiment, referring to Figure 7, the second groove 15 is formed by being recessed inwardly from the middle of the side edge of the connecting portion 11 away from the fixing portion 12 along the length direction Y1 of the elastic connector 10. The depth and width of the inward recess of the second groove 15 are both greater than the depth and width of the inward recess of the first groove 13. The second groove 15 divides the connecting portion 11 into two connecting blocks 111 spaced apart along the width direction Y2 of the elastic connector 10. The two connecting blocks 111 are respectively provided with two first connecting holes 112. The groove surface of the second groove 15 is also provided with a protruding support portion 16, which is used to support the detection member 20 installed on the second surface 18. Specifically, the portion of the detection member 20 extending into the second groove 15 is attached to the surface of the support portion 16. The support portion 16 and the magnifying hole 14 are both located in the middle of the length direction Y1 of the elastic connector 10, and the two are spaced apart. In other embodiments, depending on the size and shape of the detection member 20, it is not necessary to additionally provide the support portion 16.

[0060] In this embodiment, referring to FIG2 , the elastic connector 10 has two oppositely disposed first and second surfaces 17 and 18. The adapter 203 is disposed on the first surface 17, and the detection member 20 is disposed on the second surface 18. In this manner, the gap between the elastic connector 10 and the heat dissipation fins 2023 can be fully utilized to install the detection member 20.

[0061] In this embodiment, referring to FIG6 , the two first grooves 13 are symmetrically arranged along the width direction Y2 of the elastic connector 10. The two first grooves 13 are symmetrical about a first symmetry axis O1, which is parallel to the length direction Y1 of the elastic connector 10. This ensures that the positions of the two first grooves 13 along the length direction Y1 of the elastic connector 10 are fixed. When the connecting portion 11 is subjected to force and the fixing portion 12 is fixed, the elastic connector 10 can deform at the fixed position along the length direction Y1 (i.e., the position where the first grooves 13 are located).

[0062] In this embodiment, referring to FIG6 , the detection member 20 includes a strain gauge 21. The strain gauge 21 comprises a first portion 211 and a second portion 212. The first portion 211 and the second portion 212 are symmetrical about a second symmetry axis O2. The second symmetry axis O2 is parallel to the width direction Y2 of the elastic connector 10 and is located between two opposing groove side surfaces of the first groove 13. This allows the strain gauge 21 to deform along the second symmetry axis O2 when the elastic connector 10 deforms at the first groove 13. This limits the deformation position of the strain gauge 21 when the connecting portion 11 is subjected to force, thereby improving the detection sensitivity of the strain sensor 100.

[0063] In this embodiment, as shown in FIG6 , the outer edge of the first portion 211 is curved, and the outer edge of the second portion 212 is also curved. This maximizes the deformation of the strain gauge 21 as a whole when the first portion 211 and the second portion 212 are bent along the second symmetry axis O2, thereby generating a more pronounced detection signal and improving the detection accuracy of the strain sensor 100.

[0064] 7 , a portion of the outer edge of the first portion 211 coincides with the edge of the portion of the support portion 16 extending outward, a portion of the outer edge of the second portion 212 coincides with the hole surface of the amplifying hole 14 on the side close to the support portion 16, an outer edge of the connection between the first portion 211 and the second portion 212 on one side coincides with the bottom surface of one first groove 13, and an outer edge of the connection between the first portion 211 and the second portion 212 on the other side coincides with the bottom surface of another first groove 13. In this way, the detection member 20 is roughly arranged in the area enclosed by the second groove 15, the amplifying hole 14 and the two first grooves 13, to ensure that the detection member 20 can detect deformation generated at any position in the area, thereby further improving the detection reliability of the strain sensor 100.

[0065] The detection member 20 is fully supported, and the strength of the detection member 20 is not negatively affected by the enlarged hole 14 , thereby ensuring the elastic deformation capability of the elastic connecting member 10 and improving the deformation sensitivity of the strain sensor 100 .

[0066] Specifically, the strain gauge 21 can be circular in shape, with the second axis of symmetry O2 corresponding to a diameter of the circle. Alternatively, the strain gauge 21 can be elliptical in shape, with the second axis of symmetry O2 corresponding to the major axis of the ellipse. In other embodiments, the shape of the strain gauge 21 can also be adjusted based on actual needs, which will not be further described here.

[0067] In this embodiment, referring to FIG6 , the detection member 20 further includes a signal transmission portion 22 , which is provided on the strain gauge 21 and is used to transmit a signal (such as a current change signal, a voltage change signal, or a resistance change signal, etc.) generated when the strain gauge 21 is deformed.

[0068] Optionally, referring to FIG5 , the strain gauge 21 is a voltage ceramic strain gauge having two stacked sheets and two signal transmission units 22 , one connected to one sheet and the other connected to the other. When the strain gauge 21 is bent, the voltage between the two sheets changes, thereby enabling strain detection. In this embodiment, the edges of the two sheets are concentric circles, with the edge of one sheet located inside the edge of the other sheet. In other embodiments, the strain gauge 21 can also form a structure that detects strain through changes in resistance or voltage.

[0069] In this embodiment, referring to Figures 2 to 4 , the printhead 200 further includes an adapter 203. One end of the adapter 203 is connected to the connecting portion 11, and the other end is connected to the nozzle assembly 202. The adapter 203 allows the strain sensor 100 to be installed at different locations within the nozzle assembly 202 as needed, thereby utilizing the space within the nozzle assembly 202 and reducing the overall size of the printhead 200.

[0070] In this embodiment, referring to FIG. 6 , the two first connection holes 112 are respectively connected to the adapter 203 via fastening structures such as bolts or pins.

[0071] In this embodiment, referring to FIG. 6 , the fixing portion 12 is provided with a plurality of second connection holes 121 , and the plurality of second connection holes 121 are respectively connected to the bracket 201 via fastening structures such as bolts or pins.

[0072] Specifically, referring to FIG. 2 , the nozzle assembly 202 includes a heat sink 2021, which includes a heat sink 2022 and a plurality of heat fins 2023. The heat sink 2022 is provided with a plurality of heat fins 2023 on both sides of the elastic connector 10 in the longitudinal direction Y1. A clearance space Q is provided above the side of the heat sink 2022 facing the strain gauge connector. The adapter 203 is disposed in the clearance space Q and connected to the heat sink 2022. The connecting portion 11 is attached to the bottom surface of the adapter 203 and connected to the heat sink 2021. The elastic connector 10 is disposed between the adapter 203 and the heat fins 2023. This improves the utilization of the heat sink 2021 without affecting the related structures of the nozzle assembly 202 for conveying consumables, thereby reducing the overall volume of the printhead 200.

[0073] Of course, in other embodiments, according to actual needs, the adapter 203 can also be installed at different positions of the nozzle assembly 202, and when the installation position changes, the connecting portion 11 of the elastic connecting member 10 can also be directly connected to the nozzle assembly 202, which is not limited here.

[0074] Optionally, referring to FIG. 2 , the nozzle assembly 202 further includes a nozzle 2026 and a throat 2025. The nozzle 2026 is connected to the heat sink 2021. One end of the throat 2025 passes through the heat sink 2021 and is connected to the nozzle 2026. The other end of the throat 2025 is connected to the extrusion mechanism. The throat 2025 is used to transport the filament extruded by the extrusion mechanism to the nozzle 2026. The nozzle 2026 is used to eject the filament onto the printing platform 301. When the nozzle assembly 202 abuts the printing platform 301, the nozzle 2026 abuts the printing platform 301.

[0075] The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent replacements of the technical solutions of the present application should not depart from the spirit and scope of the technical solutions of the present application.

Claims

1. A strain sensor, characterized in that: include: An elastic connector, the elastic connector having a connecting portion and a fixing portion spaced apart along its length direction, and first grooves are formed on opposite sides of a middle portion of the connecting portion and inwardly concave along the width direction of the elastic connector, the first grooves being used to enhance the elastic deformation capacity of the connecting portion; A detection member, the detection member is attached to the middle of one side surface of the connecting portion, and the detection member is used to detect the deformation of the elastic connecting member; The elastic connecting member is further provided with an enlarged hole between the detecting member and the fixing portion.

2. The strain sensor according to claim 1, characterized in that: The two first grooves are symmetrically arranged along the width direction of the elastic connecting member, the two first grooves are symmetrical about the first symmetry axis, and the edge of the detection member does not exceed the edge of the first groove.

3. The strain sensor according to claim 1 or 2, characterized in that: The detection member includes a strain gauge, which includes a first part and a second part. The first part and the second part are symmetrical about a second symmetry axis. The second symmetry axis is parallel to the width direction of the elastic connecting member and is located between two oppositely arranged groove sides of the first groove.

4. The strain sensor according to any one of claims 1 to 3, characterized in that: The connecting portion is provided with a second groove, which is formed inwardly from the middle of the edge of one side of the connecting portion away from the fixing portion along the length direction of the elastic connecting member. The second groove is used to guide the elastic connecting member to deform at the second groove when it bends from one side to the other side in its width direction.

5. The strain sensor according to claim 4, characterized in that: The groove surface of the second groove is also provided with a protruding support portion, and a part of the detection member is attached to the support portion.

6. The strain sensor according to any one of claims 1 to 5, characterized in that: The distance between the first groove and the connecting portion is L1, the distance between the first groove and the fixing portion is L2, and L2 / L1 is between 4 and 7.

7. A print head for extruding consumables on a printing platform, characterized in that: The print head comprises: A bracket, the bracket being used to connect the transfer device; A nozzle assembly, the nozzle assembly is used to extrude consumables; The strain sensor according to any one of claims 1 to 6, wherein a fixed portion of the strain sensor is connected to the bracket, a connecting portion of the strain sensor is connected to the nozzle assembly, and the strain sensor is used to be triggered when the nozzle assembly abuts against the printing platform.

8. The print head according to claim 7, characterized in that: The print head also includes a transfer component, one end of which is connected to the connection portion, and the other end of which is connected to the nozzle assembly.

9. The print head according to claim 8, characterized in that: The nozzle assembly includes a heat sink, a side surface of the adapter abuts against and is connected to the heat sink, and the connecting portion is attached to the bottom surface of the adapter and is connected to the heat sink.

10. A 3D printer, characterized in that: include: Printing platform; A print head as claimed in any one of claims 7 to 9; The transfer device is connected to the print head and is used to drive the print head to move relative to the printing platform.

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