Spray head structure of biological 3D printer with decoupling control of wire height and wire width and printing method

Abstract

The invention relates to a silk height and silk width decoupling control biological 3D printer spray head structure and a printing method, the spray head structure comprises a rotary charging barrel structure comprising a rotary charging barrel, and the bottom end of the rotary charging barrel is connected with a rectangular opening nozzle; the rotary charging barrel rotates to drive the rectangular opening nozzle to rotate by a set deflection angle; a push rod structure hermetically and slidably penetrates through the top end of the rotary charging barrel; the extrusion shaft lead screw module is used for providing axial extrusion force for the printing material through a push rod structure so that the printing material can be extruded to form microfilaments; the spray head supporting seat is used for supporting the extrusion shaft lead screw module and the rotary charging barrel structure; and the deflection angle, the scanning speed and the printing height of the rectangular opening nozzle are adjusted through the control part so that the height and the width of the section of the microfilament can be controlled and adjusted in a decoupling mode. The section height and width of the extruded microfilament can be dynamically controlled, variable resolution and rapid printing of the gradient heterostructure are achieved, and meanwhile the requirement for multi-material printing is met.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a biological 3D printer nozzle structure with decoupling control of wire height and wire width and a printing method. Background Art

[0002] Extrusion is a large category of processes in the field of biological 3D printing, and fused deposition modeling (FDM) and direct ink writing (DIW) are two typical sub-processes. They can extrude materials in the form of microfilaments through the piston push rod on the nozzle, and make three-dimensional movements according to the path information under the control of the computer, so that the microfilaments are controlled and deposited and stacked in space. The difference is that FDM needs to heat the material from solid to molten state (liquid state) first, and solidify it after extrusion; while DIW does not have the process of heating to molten state, and the liquid material is directly extruded and formed by other cross-linking methods (such as ionic cross-linking and photo-cross-linking). In recent years, the multi-material composite printing process that combines hot-melt materials using FDM technology and hydrogel materials using DIW technology has become a research hotspot. The in vivo implant constructed in this way takes into account both mechanical strength and cell activity, and has great clinical application value.

[0003] Natural tissues and organs have complex gradient heterogeneous structures, which requires that the height (wire height) and width (wire width) of the microwire cross-section can change continuously to simulate the natural tissue structure.

[0004] Existing technology 1: Using traditional circular nozzles to print hot-melt materials (such as polycaprolactone), the continuous change of microfilament width is achieved by adjusting process parameters (such as scanning speed and printing height), but the microfilament height will change accordingly, making it impossible to decouple the resolution of the XY plane and the resolution of the Z axis. Therefore, this method requires additional printing of compensation layers at positions with higher Z-axis resolution, which increases the complexity of the process and reduces printing fidelity.

[0005] Prior art 2: A nozzle with a rotating mechanism and a flat needle is used to print hydrogel materials. The cross-section of the printed microfilaments is elliptical and has uniform width. However, this method does not study the control effect of process parameters (such as rotation angle and scanning speed) on the filament width, and does not achieve variable resolution printing. In addition, the above studies do not consider the special requirements of multi-material printing for nozzle design, such as the modular design of the temperature control system.

[0006] Therefore, in order to construct natural tissue organs with complex gradient heterogeneous structures while taking into account mechanical strength and cell activity, new equipment and processes are urgently needed to achieve decoupled control of wire height and wire width and meet the requirements of multi-material printing.

[0007] Therefore, the inventor, relying on many years of experience and practice in related industries, proposes a biological 3D printer nozzle structure and printing method with decoupling control of wire height and wire width to overcome the defects of the prior art. Summary of the invention

[0008] The purpose of the present invention is to provide a biological 3D printer nozzle structure and printing method with decoupled control of filament height and filament width, which can dynamically control the cross-sectional height and width of the extruded microfilaments, achieve variable resolution and rapid printing of gradient heterogeneous structures, and meet the requirements of multi-material printing at the same time.

[0009] The object of the present invention is achieved by providing a biological 3D printer nozzle structure with decoupling control of wire height and wire width, comprising:

[0010] A rotating barrel structure, comprising a rotating barrel for accommodating printing materials, wherein the bottom end of the rotating barrel is conductively connected to a rectangular opening nozzle capable of extruding microfilaments with a rectangular cross-section; the rotating barrel can rotate around the central axis of the barrel to drive the rectangular opening nozzle to rotate a set deflection angle; a push rod structure is sealed and slidably penetrated through the top end of the rotating barrel; and a temperature control system for controlling the printing temperature is connected to the rotating barrel;

[0011] An extrusion shaft screw module is connected to the push rod structure, and the extrusion shaft screw module provides an axial extrusion force to the printing material through the push rod structure so that the printing material is extruded from the rectangular opening nozzle to form microfilaments;

[0012] A nozzle support seat, used to support the extrusion shaft screw module and the rotating barrel structure; the nozzle support seat can move along the X-axis, Y-axis, and Z-axis of the spatial coordinate system to change the spatial coordinate position of the rectangular opening nozzle;

[0013] The control unit, the rotating barrel structure, the extrusion shaft screw module, and the nozzle support seat are all electrically connected to the control unit; the deflection angle, scanning speed and printing height of the rectangular opening nozzle are adjusted by the control unit to decouple the control and adjust the cross-sectional height and width of the microfilament.

[0014] In a preferred embodiment of the present invention, the rotating barrel structure also includes a rotating platform and a rotating motor connected to the nozzle support seat, the rotating platform includes a platform connecting part and a platform rotating part, the platform connecting part is fixedly connected to the nozzle support seat, the platform rotating part is connected to the rotating motor through a transmission structure, and the platform rotating part can rotate relative to the platform connecting part under the drive of the rotating motor; the rotating barrel can be connected to the platform rotating part, and the rotating motor is electrically connected to the control part, and the control part drives the platform rotating part, the rotating barrel, and the rectangular opening nozzle to rotate to a set deflection angle by controlling the rotating motor.

[0015] In a preferred embodiment of the present invention, a platform through hole is arranged on the rotating platform; the bottom end of the platform rotating part is connected to the coaxial positioning sleeve, the bottom of the coaxial positioning sleeve is connected to the barrel shell, the rotating barrel passes through the platform through hole, the inner cavity of the coaxial positioning sleeve and the inner cavity of the barrel shell, and the rotating barrel is fixedly connected to the barrel shell; a concentric positioning structure for adjusting the coaxiality of the barrel shell and the rotating platform is arranged on the side wall of the coaxial positioning sleeve; the radial interval between the inner wall of the barrel shell and the outer wall of the rotating barrel constitutes a temperature control system accommodating space.

[0016] In a preferred embodiment of the present invention, the inner cavity of the coaxial positioning sleeve includes a sleeve through hole extending downward from the top end and a sleeve opening arranged upward from the bottom end, and the aperture size of the sleeve opening is larger than the aperture size of the sleeve through hole; the sleeve opening, the sleeve through hole and the platform through hole are connected; the top end of the barrel shell is embedded in the sleeve opening, and the concentric positioning structure includes correction screws arranged at intervals along the circumferential direction, and one end of the correction screw is against the top side wall of the barrel shell.

[0017] In a preferred embodiment of the present invention, a shell flange is provided at the top end of the barrel shell, the shell flange is embedded in the sleeve opening, the aperture size of the sleeve opening is larger than the outer diameter size of the shell flange; one end of the correction screw is pressed against the side wall of the shell flange to adjust the coaxiality of the barrel shell and the rotating platform; a sleeve cover plate is provided under the coaxial positioning sleeve, the sleeve cover plate is connected to the shell flange by a first connecting screw, and the sleeve cover plate is connected to the coaxial positioning sleeve by a second connecting screw.

[0018] In a preferred embodiment of the present invention, the rotating barrel includes a cylindrical portion and a conical portion which are connected to each other, the conical portion is located below the bottom end of the barrel shell, the cylindrical portion extends upward from the conical portion, and the bottom end of the conical portion is connected to the rectangular opening nozzle; a barrel flange is provided on the outer wall of the rotating barrel at the bottom end of the barrel shell, and the barrel flange is connected to the bottom end of the barrel shell by a third connecting screw.

[0019] In a preferred embodiment of the present invention, the temperature control system includes a fixed seat and a temperature control module; the fixed seat includes a seat body with a fan-shaped cross-section, and the seat body is inserted into the inner cavity of the platform through hole and the coaxial positioning sleeve; the top of the seat body is exposed from the platform through hole to set a fixed seat flange for connecting to the nozzle support seat, and the fixed seat flange is connected to the nozzle support seat by a fourth connecting screw; an annular seat is set at the bottom end of the seat body, and the temperature control module is connected below the annular seat, and a module through hole is set on the temperature control module, and the temperature control module is set in the accommodating space of the temperature control system; the rotating barrel is passed through the seat body and the module through hole so that the temperature control system can control the temperature of the rotating barrel.

[0020] In a preferred embodiment of the present invention, the push rod structure includes a push rod body, the bottom end of the push rod body is sealed and slidably penetrated in the rotating barrel from top to bottom, and the push rod body and the rotating barrel are circumferentially fixedly arranged; the top end of the push rod body is connected to a connecting sleeve, the top end of the connecting sleeve is rotatably connected to the bottom end of the connecting seat block through a thrust bearing, and the connecting seat block is connected to the extrusion shaft screw module;

[0021] The push rod body can rotate with the rotating barrel, and the push rod body can push the printing material in the rotating barrel to extrude from the rectangular opening nozzle to form microfilaments under the axial action of the extrusion shaft screw module.

[0022] In a preferred embodiment of the present invention, the thrust bearing includes a tightening ring, a loose ring, a steel ball and a retaining frame; the loose ring is arranged at the bottom end of the connecting seat block; and the tightening ring is arranged at the top end of the connecting sleeve.

[0023] In a preferred embodiment of the present invention, the bottom end of the connecting seat block is detachably connected to a positioning column extending downward, and the connecting sleeve is axially fixedly rotatably sleeved on the positioning column.

[0024] In a preferred embodiment of the present invention, a stepped hole with a larger diameter at the bottom and smaller diameter at the top is provided downwardly from the top of the connecting sleeve, a column flange is provided at the bottom end of the positioning column, the positioning column passes through the stepped hole from bottom to top, and the top surface of the column flange abuts against the step surface of the stepped hole.

[0025] In a preferred embodiment of the present invention, a T-slot extending radially upward is provided at the bottom end of the connecting sleeve, a rod flange which can be nested in the T-slot is provided at the top end of the push rod body, and a fixing screw which can fix the rod flange is connected to the bottom end of the connecting sleeve.

[0026] In a preferred embodiment of the present invention, the top end of the rotating barrel is connected to a rotating positioning buckle that can be snapped onto the outside of the push rod body, a limiting protrusion is provided on the rotating positioning buckle, and a guide groove is provided on the side wall of the push rod body. The guide groove is slidably sleeved on the limiting protrusion to fix the push rod body circumferentially relative to the rotating barrel.

[0027] In a preferred embodiment of the present invention, the extrusion axis lead screw module includes an extrusion axis motor, a lead screw and a slider, the lead screw is vertically connected to the nozzle support seat, the top end of the lead screw is connected to the extrusion axis motor, the slider is slidably mounted on the lead screw, the extrusion axis motor drives the lead screw to rotate to drive the slider to move along the lead screw; the connecting seat block is connected to the slider; the extrusion axis motor is electrically connected to the control unit.

[0028] In a preferred embodiment of the present invention, the nozzle support seat includes a longitudinal support portion and a transverse support portion, one end of the transverse support portion is fixedly connected to one side of the longitudinal support portion; the longitudinal support portion is located below the transverse support portion and connected to the three-dimensional motion platform; the longitudinal support portion is located above the transverse support portion and connected to the extrusion shaft screw module; the rotating barrel structure is connected to the transverse support portion.

[0029] The object of the present invention can also be achieved in this way. A printing method of a biological 3D printer nozzle structure with decoupling control of wire height and wire width as described above comprises the following steps:

[0030] Step a, installing the biological 3D printer nozzle structure with decoupling control of wire height and wire width on the printer, and the push rod structure is not installed temporarily;

[0031] Step b, starting the printer, setting the printing temperature of the temperature control system and keeping the rotating barrel structure warm;

[0032] Step c, injecting printing material into the rotating barrel and installing the push rod structure;

[0033] Step d, performing concentric correction on the position of the rectangular opening nozzle;

[0034] Step e: according to the wire height and wire width requirements of different parts of the model, the model is sliced ​​and a G code instruction is generated, which includes the displacement information of the three-dimensional motion axis, the extrusion axis, and the rotation axis;

[0035] Step f: During the printing process, the printing parameters are set according to the control model, and the height and width of the cross section of the extruded microfilaments are changed in real time by adjusting the deflection angle, scanning speed and printing height of the rectangular opening nozzle.

[0036] In a preferred embodiment of the present invention, the control model in step f includes:

[0037]

[0038] h p =K*h f ;

[0039]

[0040] Among them, v s is the scanning speed, h p is the printing height, K is the control coefficient, d e is the diameter of the push rod body, v e is the extrusion speed of the push rod body, w f is the microfilament width, h f is the microwire height, d n is the width of the rectangular opening, w n is the length of the rectangular opening, and θ is the angle between the normal direction of the rectangular opening and the scanning speed direction.

[0041] As described above, the bio-3D printer nozzle structure and printing method with decoupling control of wire height and wire width of the present invention have the following beneficial effects:

[0042] The present invention achieves decoupling control of the height and width of extruded microfilaments by adjusting the deflection angle, printing height and scanning speed of the rectangular opening nozzle in real time, and can be used for the construction of natural tissue organs.

[0043] The real-time controllable adjustment of the height and width of the printed microfilament has many advantages over the existing technology:

[0044] (1) It can effectively simulate the gradient heterogeneous structure of natural tissues: for example, the gradient pore distribution of bone compaction-spongy bone, which reduces the wire width in large pores and increases the wire width in small pores; for example, the wedge-shaped structure of the meniscus, which reduces the wire height in the inner white area and increases the wire height in the outer red area.

[0045] (2) Variable resolution printing can be achieved, taking into account both printing accuracy and speed: according to the different partition structure characteristics, the printing wire width and wire height can be flexibly controlled. For example, in areas with simple shapes and low precision requirements, the wire height and wire width can be increased to shorten the printing time; in areas with complex shapes and high precision requirements, the wire height and wire width can be reduced to improve the printing quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The following drawings are only intended to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0047] in:

[0048] Figure 1This is a schematic structural diagram of the bio-3D printer nozzle structure with decoupling control of wire height and wire width according to the present invention.

[0049] Figure 2a It is a cross-sectional view of the push rod structure of the present invention.

[0050] Figure 2b It is a cross-sectional view of the assembly relationship between the rotation positioning buckle and the push rod body of the present invention.

[0051] Figure 3a It is a schematic diagram of the structure of the temperature control system used for DIW process of the present invention.

[0052] Figure 3b It is a schematic diagram of the structure of the temperature control system used in the FDM process of the present invention.

[0053] Figure 4 It is a cross-sectional view of the rotating barrel structure of the present invention.

[0054] Figure 5 It is a schematic diagram of the concentric correction process of the rectangular opening nozzle of the present invention.

[0055] Figure 6a This is a flow chart of the visual correction algorithm in Example 2.

[0056] Figure 6b This is a diagram showing the recognition effect of the center of the rectangular opening nozzle in Example 2.

[0057] Figure 7a Schematic diagram of printing higher filament height microfilaments in Example 4 of the present invention.

[0058] Figure 7b Schematic diagram of printing microwires with relatively low wire height in Example 4 of the present invention.

[0059] Figure 7c This is a diagram showing the experimental results of controlling the wire height printing in Example 4 of the present invention.

[0060] Figure 8a This is a schematic diagram of printing microwires with larger wire width in Example 4 of the present invention.

[0061] Figure 8b Schematic diagram of printing microwires with smaller wire width in Example 4 of the present invention.

[0062] Figure 8c This is a diagram of the experimental results of controlling the wire width printing in Example 4 of the present invention.

[0063] Fig. 9 This is a schematic diagram of multi-material printing in Example 5 of the present invention.

[0064] In the figure:

[0065] 1. Nozzle support seat; 11. Longitudinal support part; 12. Horizontal support part;

[0066] 2. Extrusion axis lead screw module; 21. Extrusion axis motor; 22. Lead screw; 23. Slider;

[0067] 3. Push rod structure; 30. Push rod body; 31. Connecting seat block; 32. Fifth connecting screw; 33. Loose ring; 34. Steel ball and retainer; 35. Tight ring; 36. Positioning column; 37. Connecting sleeve; 38. Fixing screw; 39. Rotating positioning buckle;

[0068] 4. Temperature control system; 41. Fixed seat; 411. Seat body; 412. Fixed seat flange; 413. Ring seat; 42. Heating tube; 43. Semiconductor chip; 44. Water cooling head; 45. Heat-conducting sleeve; 46. Temperature sensor; 47. Fastening seat;

[0069] 5. Rotating barrel structure; 51. Coaxial positioning sleeve; 511. Through hole on sleeve; 512. Sleeve opening; 52. Sleeve cover plate; 53. Barrel shell; 531. Shell flange; 54. Rotating barrel; 541. Cylinder; 542. Cone; 543. Barrel flange; 55. Rotating platform; 551. Platform connecting part; 552. Platform rotating part; 56. Rotating motor; 57. Correction screw; 581. First connecting screw; 582. Second connecting screw; 583. Third connecting screw;

[0070] 6. Rectangular opening nozzle. DETAILED DESCRIPTION

[0071] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0072] The specific embodiments of the present invention described herein are only used to explain the purpose of the present invention and cannot be understood as limiting the present invention in any way. Under the guidance of the present invention, technicians can conceive of any possible variations based on the present invention, which should be considered to belong to the scope of the present invention. It should be noted that when an element is referred to as "arranged on" another element, it can be directly on the other element or there can also be a central element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be a central element at the same time. The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, or it can be the internal communication of two elements, it can be directly connected, or it can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation method.

[0073] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally 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 "and / or" used herein includes any and all combinations of one or more related listed items.

[0074] like Figures 1 to 4 As shown, the present invention provides a biological 3D printer nozzle structure with decoupling control of wire height and wire width, comprising:

[0075] The rotating barrel structure 5 includes a rotating barrel 54 for accommodating printing materials, the bottom end of the rotating barrel 54 is connected to a rectangular opening nozzle 6 capable of extruding microfilaments with a rectangular cross section; the rotating barrel 54 can rotate around the central axis of the barrel to drive the rectangular opening nozzle 6 to rotate a set deflection angle; the top end of the rotating barrel 54 is sealed and slidably penetrated by a push rod structure 3; the rotating barrel 54 is connected to a temperature control system 4 for controlling the printing temperature;

[0076] The extrusion shaft screw module 2 is connected to the push rod structure 3. The extrusion shaft screw module 2 provides an axial extrusion force to the printing material through the push rod structure 3 so that the printing material is extruded from the rectangular opening nozzle 6 to form microfilaments;

[0077] The nozzle support seat 1 is used to support the extrusion shaft screw module 2 and the rotating barrel structure 5; the nozzle support seat 1 can move along the X-axis, Y-axis, and Z-axis of the spatial coordinate system to change the spatial coordinate position of the rectangular opening nozzle 6;

[0078] The control unit, the rotating barrel structure 5, the extrusion shaft screw module 2, and the nozzle support seat 1 are all electrically connected to the control unit; the deflection angle, scanning speed and printing height of the rectangular opening nozzle 6 are adjusted by the control unit to decouple the control to adjust the cross-sectional height and width of the microfilament.

[0079] The present invention achieves decoupling control of the height and width of extruded microfilaments by adjusting the deflection angle, printing height and scanning speed of the rectangular opening nozzle 6 in real time, and can be used for the construction of natural tissue organs.

[0080] The real-time controllable adjustment of the height and width of the printed microfilament has many advantages over the existing technology:

[0081] (1) It can effectively simulate the gradient heterogeneous structure of natural tissues: for example, the gradient pore distribution of bone compaction-spongy bone, which reduces the wire width in large pores and increases the wire width in small pores; for example, the wedge-shaped structure of the meniscus, which reduces the wire height in the inner white area and increases the wire height in the outer red area.

[0082] (2) Variable resolution printing can be achieved, taking into account both printing accuracy and speed: according to the different partition structure characteristics, the printing wire width and wire height can be flexibly controlled. For example, in areas with simple shapes and low precision requirements, the wire height and wire width can be increased to shorten the printing time; in areas with complex shapes and high precision requirements, the wire height and wire width can be reduced to improve the printing quality.

[0083] Further, if Figure 1 , Figure 4 As shown, the rotating barrel structure 5 also includes a rotating platform 55 and a rotating motor 56 connected to the nozzle support seat 1, the rotating platform 55 includes a platform connecting part 551 (stationary surface) and a platform rotating part 552 (rotating surface), the platform connecting part 551 is fixedly connected to the nozzle support seat 1, and the platform rotating part 552 is connected to the rotating motor 56 through a transmission structure, and the transmission structure can adopt a gear transmission structure, a belt transmission structure, etc.; the platform rotating part 552 can rotate relative to the platform connecting part 551 under the drive of the rotating motor 56; the rotating barrel 54 can be connected to the platform rotating part 552, and the rotating motor 56 is electrically connected to the control part, and the control part drives the platform rotating part 552, the rotating barrel 54, and the rectangular opening nozzle 6 to rotate to a set deflection angle by controlling the rotating motor 56, and the overall control can realize intelligent and precise control to ensure precise control of the deflection angle of the rectangular opening nozzle 6.

[0084] Further, if Figure 1 , Figure 4As shown, a platform through hole is set on the rotating platform 55; the bottom end of the platform rotating part 552 is connected to the coaxial positioning sleeve 51, the coaxial positioning sleeve 51 is cylindrical, and the bottom of the coaxial positioning sleeve 51 is connected to the barrel shell 53, and the barrel shell 53 is hollow cylindrical; the rotating barrel 54 passes through the platform through hole, the inner cavity of the coaxial positioning sleeve 51 and the inner cavity of the barrel shell 53, and the rotating barrel 54 is fixedly connected to the barrel shell 53; the bottom end of the barrel shell 53 is provided with a shell bottom hole, the aperture size of the shell bottom hole is slightly larger than the outer diameter size of the rotating barrel 54, and the bottom end of the rotating barrel 54 passes through the shell bottom hole; a concentric positioning structure for adjusting the coaxiality of the barrel shell 53 and the rotating platform 55 is set on the side wall of the coaxial positioning sleeve 51; the radial interval between the inner wall of the barrel shell 53 and the outer wall of the rotating barrel 54 constitutes a temperature control system accommodating space to protect the temperature control system.

[0085] Further, if Figure 4 , Figure 5 As shown, the inner cavity of the coaxial positioning sleeve 51 includes a sleeve through hole 511 extending downward from the top and a sleeve opening 512 extending upward from the bottom, and the aperture size of the sleeve opening 512 is larger than the aperture of the sleeve through hole 511; the sleeve opening 512, the sleeve through hole 511 and the platform through hole are connected; the top of the barrel shell 53 is embedded in the sleeve opening 512, and the coaxial positioning structure includes a correction screw 57 arranged at intervals along the circumferential direction, and one end of the correction screw 57 abuts against the top side wall of the barrel shell 53. In a specific embodiment, the side wall of the coaxial positioning sleeve 51 is equidistantly distributed with four threaded holes arranged in the radial direction, and the relative position of the barrel shell 53 and the coaxial positioning sleeve 51 is corrected by adjusting the depth of the correction screw 57.

[0086] Further, if Figure 4 As shown, a shell flange 531 is provided at the top of the barrel shell 53, and the shell flange 531 is embedded in the sleeve opening 512, and the aperture size of the sleeve opening 512 is larger than the outer diameter size of the shell flange 531; one end of the correction screw 57 is pressed against the side wall of the shell flange 531 to adjust the coaxiality between the barrel shell 53 and the rotating platform 55; a sleeve cover plate 52 is provided below the coaxial positioning sleeve 51, and the sleeve cover plate 52 is annular; the sleeve cover plate 52 is connected to the shell flange 531 by a first connecting screw 581, and the sleeve cover plate 52 is connected to the coaxial positioning sleeve 51 by a second connecting screw 582.

[0087] Further, if Figure 1 , Figure 4As shown, the rotating barrel 54 includes a cylindrical portion 541 and a conical portion 542 which are connected to each other. The conical portion 542 is located below the bottom end of the barrel shell 53, and the cylindrical portion 541 extends upward from the conical portion 542. The bottom end of the conical portion 542 is connected to the rectangular opening nozzle 6 (threaded connection). A barrel flange 543 is provided on the outer wall of the rotating barrel 54 at the bottom end of the barrel shell 53, and the barrel flange 543 is connected to the bottom end of the barrel shell 53 by a third connecting screw 583.

[0088] In order to meet the needs of multi-material printing, the rotary barrel 54 is made of medical-grade stainless steel, which is universal for different materials and process types; it is suitable for both hot-melt materials of FDM and hydrogel materials of DIW.

[0089] Further, if Figure 3a , Figure 3b As shown, the temperature control system 4 adopts a modular design; the temperature control system 4 includes a fixed seat 41 and a temperature control module; the fixed seat 41 includes a seat body 411 with a fan-shaped cross-section, and the seat body 411 is penetrated through the platform through hole and the inner cavity of the coaxial positioning sleeve 51; the top of the seat body 411 is exposed to the platform through hole. A fixed seat flange 412 for connecting to the nozzle support seat 1 is arranged, and the fixed seat flange 412 is connected to the nozzle support seat 1 by a fourth connecting screw, and the temperature control system 4 does not rotate; a circular ring seat 413 is arranged at the bottom end of the seat body 411, and the temperature control module is connected to the bottom of the circular ring seat 413, and the circular ring seat 413 is circumferentially provided with a seat change through hole for connecting to the temperature control module. A module through hole is set on the temperature control module, and the temperature control module is set in the accommodating space of the temperature control system; the rotating barrel 54 is passed through the seat body 411 and the module through hole so that the temperature control system can control the temperature of the rotating barrel 54. The aperture size of the module through hole is slightly larger than the outer diameter size of the rotating barrel 54. A small gap is left between the temperature control module and the rotating barrel 54 to transfer heat through thermal radiation and thermal convection.

[0090] In order to meet the needs of multi-material printing, the temperature control module can be replaced according to different materials and process types. When performing FDM printing of hot melt materials, the FDM process temperature control module is used, which heats in one direction; when performing DIW printing of hydrogel materials, the DIW process temperature control module is used, which controls the temperature in two directions.

[0091] Further, if Figure 1 , Figure 2a , Figure 2bAs shown, the push rod structure 3 includes a push rod body 30, which is cylindrical; the bottom end of the push rod body 30 is sealed and slidably penetrated in the rotating barrel 54 from top to bottom, and the push rod body 30 and the rotating barrel 54 are circumferentially fixed; a sealing ring is arranged on the bottom end surface of the push rod body 30 to prevent leakage of printing material during extrusion; the top end of the push rod body 30 is connected to a connecting sleeve 37, and the top end of the connecting sleeve 37 is rotatably connected to the bottom end of the connecting seat block 31 through a thrust bearing, and the connecting seat block 31 is connected to the extrusion shaft screw module 2; the connecting seat block 31 has two longitudinal and transverse support surfaces, the longitudinal support surface is fixed on the extrusion shaft screw module, and the transverse support surface is used to fix the loose ring 33 of the thrust bearing; the push rod body 30 can rotate with the rotating barrel 54, and the push rod body 30 can push the printing material in the rotating barrel 54 to extrude from the rectangular opening nozzle 6 to form microfilaments under the axial action of the extrusion shaft screw module 2.

[0092] Further, if Figure 2a As shown, the thrust bearing is a plane thrust ball bearing, including a tight ring 35, a loose ring 33, a steel ball and a retaining frame 34; the loose ring 33 is arranged at the bottom end of the connecting seat block 31; the tight ring 35 is arranged at the top end of the connecting sleeve 37.

[0093] Specifically, the connecting seat block 31 extends a horizontal platform, and a small cylindrical platform protrudes from its lower end surface, and the tight ring 35 of the thrust bearing can be inserted coaxially. The top of the connecting sleeve 37 is provided with a circular groove, and the inner ring of the tight ring 35 is clamped with the inner cylindrical surface of the circular groove by interference fit.

[0094] Further, if Figure 2a As shown, the bottom end of the connecting seat block 31 is detachably connected to the positioning column 36 extending downward, and the connecting sleeve 37 is axially fixedly rotatably sleeved on the positioning column 36. In a specific embodiment of the present invention, the positioning column 36 is connected to the bottom end of the connecting seat block 31 by a fifth connecting screw 32.

[0095] Further, if Figure 2a As shown, a stepped hole with a larger diameter at the bottom and a smaller diameter at the top is set downwardly at the top of the connecting sleeve 37, and a column flange is set at the bottom end of the positioning column 36. The positioning column 36 passes through the stepped hole from bottom to top, and the top surface of the column flange abuts against the step surface of the stepped hole.

[0096] The outer diameter of the column flange is slightly smaller than the major diameter of the stepped hole, and the positioning column 36 has a concentric positioning function for the connecting sleeve 37; a through hole is opened in the center of the positioning column 36, and the fifth connecting screw 32 is inserted to fix it with the connecting seat block 31; the column flange supports the connecting sleeve 37 so that it does not separate from the connecting seat block 31.

[0097] Further, if Figure 1 , Figure 2aAs shown, a T-slot extending radially upward is provided at the bottom end of the connecting sleeve 37, a rod flange which can be nested in the T-slot is provided at the top end of the push rod body 30, and a fixing screw 38 which can fix the rod flange is connected to the bottom end of the connecting sleeve 37.

[0098] The upper side of the connecting sleeve 37 is cylindrical, and the radial ends of its lower side are rectangular side walls. A T-slot is passed through its normal direction so that the rod flange can be laterally embedded in the T-slot; its bottom end has a threaded hole, and the push rod body 30 is clamped and fixed by screwing in the fixing screw 38.

[0099] Further, if Figure 1 , Figure 2a As shown, the top end connection of the rotating barrel 54 can be buckled with the rotating positioning buckle 39 on the outside of the push rod body 30, a limiting protrusion is set on the rotating positioning buckle 39, and a guide groove (long strip groove) is set on the side wall of the push rod body 30, and the guide groove has a shape that is complementary to the limiting protrusion; the guide groove is slidably sleeved on the limiting protrusion to fix the push rod body 30 circumferentially relative to the rotating barrel 54, so that the two can maintain synchronous rotation.

[0100] The rotation positioning buckle 39 is semi-cylindrical, with two pieces symmetrically distributed along the radial direction of the rotating barrel 54, and fixed to the rotating barrel 54 by screws; limiting protrusions are respectively provided on the two rotation positioning buckles 39, and the limiting protrusions are embedded in the guide grooves on both sides of the push rod body 30 to ensure that the two rotate synchronously.

[0101] Further, if Figure 1 As shown, the extrusion axis lead screw module 2 includes an extrusion axis motor 21, a lead screw 22 and a slider 23. The lead screw 22 is vertically connected to the nozzle support seat 1. The top of the lead screw 22 is connected to the extrusion axis motor 21. The slider 23 is slidably sleeved on the lead screw 22. The extrusion axis motor 21 drives the lead screw 22 to rotate to drive the slider 23 to move along the lead screw 22. The connecting seat block 31 is connected to the slider 23. The extrusion axis motor 21 is electrically connected to the control unit. The slider 23 is connected to the push rod body 30. By accurately controlling the position of the slider 23, the push rod body 30 can achieve bidirectional displacement in the axial direction. The downward displacement is extrusion, and the upward displacement is retraction.

[0102] Further, if Figure 1As shown, the nozzle support seat 1 includes a longitudinal support portion 11 and a transverse support portion 12, which are used to fix the positions of various components and provide mechanical support. One end of the transverse support portion 12 is fixedly connected to one side of the longitudinal support portion 11; the longitudinal support portion 11 is located below the transverse support portion 12 and is connected to a three-dimensional motion platform (which can adopt existing technology and can achieve motion along the X-axis, Y-axis, and Z-axis directions of the spatial coordinate system); the longitudinal support portion 11 is located above the transverse support portion 12 and is connected to the extrusion axis screw module 2 (the extrusion axis screw module is connected to the longitudinal support portion 11 through threads); the rotating barrel structure 5 is connected to the transverse support portion 12.

[0103] Reinforcing ribs are provided between the longitudinal supporting portion 11 and the transverse supporting portion 12 to enhance the structural strength and reduce mechanical deformation during extrusion.

[0104] A semicircular groove is provided on the transverse support portion 12, and the fixing seat flange 412 can be placed in the semicircular groove; at the same time, the top thereof has equidistant countersunk holes along the tangential direction for fixing with the nozzle support frame.

[0105] The printing method of the biological 3D printer nozzle structure using the wire height and wire width decoupling control of the present invention comprises the following steps:

[0106] Step a, installing the biological 3D printer nozzle structure with decoupling control of wire height and wire width of the present invention on the printer, and the push rod structure 3 is not installed temporarily;

[0107] Step b, starting the printer (existing technology), setting the printing temperature of the temperature control system and keeping the rotating barrel structure 5 warm;

[0108] Step c, injecting printing material into the rotating barrel 54 and installing the push rod structure 3;

[0109] Step d, concentrically calibrating the position of the rectangular opening nozzle 6;

[0110] Step e, according to the wire height and wire width requirements of different parts of the model, the model is sliced ​​and a G code instruction is generated, which includes the displacement information of the three-dimensional motion axis (the X axis, Y axis, and Z axis of the spatial coordinate system), the extrusion axis (the extrusion axis lead screw module 2 and the push rod body 30), and the rotation axis (the rotating barrel 54);

[0111] Step f: During the printing process, the printing parameters are set according to the control model, and the height and width of the cross section of the extruded microfilaments are changed in real time by adjusting the deflection angle, scanning speed and printing height of the rectangular opening nozzle 6.

[0112] Wherein, in step f, the printing parameters are set according to the following control model:

[0113]

[0114] h p =K*h f ;

[0115]

[0116] Among them, v s is the scanning speed, h p is the printing height, K is the control coefficient, d e is the diameter of the push rod body, v e is the extrusion speed of the push rod body, w f is the microfilament width, h f is the microwire height, d n is the width of the rectangular opening, w n is the length of the rectangular opening, and θ is the angle between the normal direction of the rectangular opening and the scanning speed direction.

[0117] Example 1

[0118] Stator and rotor during printing process

[0119] During the printing process, the push rod body 30 should rotate synchronously with the rotating barrel structure 5; otherwise, the push rod body 30 will rotate relative to the rotating barrel structure 5, introducing a turbulent rotating flow field to the printing material between the two, affecting the printing effect.

[0120] In order to achieve the above functions and maintain the original axial thrust transmission function of the push rod body 30, the push rod structure 3 is improved in two aspects. Figure 2b As shown, the guide grooves on both sides of the push rod body 30 and the limiting protrusions on the inner wall of the rotation positioning buckle 39 can be nested and meshed with each other; so that when the rotating barrel 54 rotates, the push rod body 30 will be driven to rotate synchronously through the rotation positioning buckle 39. Figure 2a As shown, the rod flange on the upper end face of the push rod body 30 is embedded in the T-slot of the connecting sleeve 37, and is pushed against the upper end face of the T-slot by a fixing screw 38 to achieve a fixed connection between the two; the fifth connecting screw 32 passes through the through hole in the center of the positioning column 36 to fix it to the connecting seat block 31.

[0121] Therefore, if Figure 4As shown, the coaxial positioning sleeve 51, the sleeve cover plate 52, the barrel shell 53, the rotating barrel 54, the push rod body 30, the rotating positioning buckle 39, the connecting sleeve 37, the tight ring 35 of the thrust bearing, and the rectangular opening nozzle 6 together constitute the rotor; the connecting seat block 31, the loose ring 33 of the thrust bearing, and the positioning column 36 together constitute the stator. The rotating motor 56 drives the entire rotor to rotate through the platform rotating part 552, and the axial thrust is transmitted between the stator and the rotor through the thrust bearing, while reducing the friction torque introduced by the rotation. In addition, the column flange at the bottom end of the positioning column 36 supports the connecting sleeve 37, ensuring that the various components of the thrust bearing will not separate from each other whether the connecting seat block 31 is squeezed downward or lifted upward; the positioning function of the positioning column 36 also helps to reduce the wear of the thrust bearing.

[0122] The installation process of the actuator is as follows:

[0123] (1) Raise the connecting block 31 to the top of the lead screw 22;

[0124] (2) The top end of the push rod body 30 is inserted into the connecting sleeve 37;

[0125] (3) Move the push rod body 30 downward until the bottom end is just inserted into the rotating barrel 54;

[0126] (4) Adjust the rotation angle of the push rod body 30 so that the guide grooves on both sides are aligned with the limiting protrusions of the rotation positioning buckle 39;

[0127] (5) Install the rotation positioning buckle 39 and nest it with the push rod body 30.

[0128] Example 2

[0129] Concentricity correction of rectangular opening nozzle 6

[0130] Due to processing and assembly errors, there is a position deviation between the opening center of the rectangular opening nozzle 6 and the rotation center of the rotating platform 55. In order to control the printing accuracy, the concentricity of the two needs to be corrected to 0.01mm. Because the coaxial positioning sleeve 51 and the barrel housing 53 are respectively fixed to the rotating platform 55 and the rectangular opening nozzle 6, it is only necessary to correct the relative position of the former to achieve the purpose of concentric correction. A high-definition macro camera (existing technology) is arranged directly below the rectangular opening nozzle 6, and its center is identified by a machine vision algorithm. The imaging parameters of the macro camera have been calibrated and designed to ensure that the resolution of a single pixel is better than 0.005mm. The specific process of the visual correction algorithm is as follows. Figure 6a As shown in Figure 2, the recognition effect of the rectangular nozzle center is as follows: Figure 6b shown.

[0131] The specific correction steps are:

[0132] (1) Loosen the first connecting screw 581 between the coaxial positioning sleeve cover plate 52 and the barrel housing 53;

[0133] (2) Control the rotating platform 55 to rotate forward and reverse, observe the position change of the center of the rectangular opening nozzle 6, and adjust the screwing depth of the four correction screws 57 respectively to support the side wall of the shell flange 531 of the barrel shell 53, so that the position of the barrel shell 53 is slightly moved, such as Figure 5 As shown;

[0134] (3) Repeat step (2) until the center position of the rectangular opening nozzle 6 no longer changes when rotating forward or reversely;

[0135] (4) Tighten the first connecting screw 581 between the coaxial positioning sleeve cover plate 52 and the barrel housing 53, and the concentric correction is completed.

[0136] Example 3

[0137] Temperature control system

[0138] The temperature control system 4 is fixedly connected to the nozzle support base 1 through the fixed base 41 and does not rotate; a small gap is left between the temperature control module and the rotating barrel 54, and heat is transferred through thermal radiation and thermal convection. The design of the temperature control module varies depending on the process type. Here, the design of the temperature control module is described in detail using the FDM process and the DIW process as examples.

[0139] like Figure 3a As shown, the temperature control range of the FDM process temperature control module is 30-200°C, and the core part is the heating cylinder 42. The heating cylinder 42 is placed coaxially with the rotating barrel 54, and the inner diameter is slightly larger than the diameter of the rotating barrel 54. The opening at one end is connected to the fixing seat 41, so that the heating cylinder 42 is fixed on the nozzle support seat 1. The heating cylinder 42 is connected to an external temperature control heating device, and a spiral black heating wire is embedded on the surface of the cylindrical side wall, so as to realize the heating and temperature control of the printing material in the barrel.

[0140] like Figure 3bAs shown, the temperature control range of the DIW process temperature control module is 5-40°C. It is based on water-cooled heat conduction and consists of a semiconductor chip 43, a water-cooled head 44, a heat-conducting sleeve 45, a temperature sensor 46, and a fastening seat 47. It is connected to external temperature control devices such as a water pump, a fan, and a thermostat through water pipes and wires. The upper part of the heat-conducting sleeve 45 is a thin-walled hollow cylindrical tube, the inner diameter of which is slightly larger than the diameter of the rotating barrel 54 and is placed coaxially with the rotating barrel 54; a flange structure is provided at its top, which is fixedly connected to the fixing seat 41; and its radial ends are rectangular side walls for fixing the wire ear temperature sensor 46 for accurate temperature measurement. The lower part of the heat-conducting sleeve 45 is a square base structure, the left and right sides of which are tightly fitted with the semiconductor chip 43, and the semiconductor chip 43 is tightly fitted with the water-cooled head 44. Each fitting surface is coated with a heat-conducting material to achieve efficient heat conduction. The fastening seat 47 has through holes on both sides, which are fixedly connected to the heat-conducting sleeve 45 by screws; the left and right sides have threaded holes, and the semiconductor chip 43 and the water-cooling head 44 are tightly pressed against the square base of the heat-conducting sleeve 45 by screwing in the screws. The semiconductor chip 43 can achieve cooling and heating respectively by applying positive and negative voltages on it.

[0141] Example 4

[0142] Decoupling control of wire height and wire width based on rectangular opening nozzle

[0143] The cross-sectional shape of the microfilament extruded by the rectangular opening nozzle 6 is rectangular, and its height and width can be decoupled and controlled by adjusting the process parameters (scanning speed, rotation angle, printing height). The setting of the process parameters can refer to the following control model:

[0144]

[0145] h p =K*h f ——(2);

[0146]

[0147] Among them, v s is the scanning speed, h p is the printing height, K is the control coefficient, d e is the piston push rod diameter, v e is the piston push rod extrusion speed, w f is the microfilament width, h f is the microwire height, d n is the width of the rectangular opening, w n is the length of the rectangular opening, and θ is the angle between the normal direction of the rectangular opening and the scanning speed direction.

[0148] Generally speaking, due to the viscosity of the printing material, the response to changes in the extrusion speed is delayed and difficult to adjust flexibly, so the extrusion speed is fixed.

[0149] Change the wire height: Figure 7a , Figure 7b As shown, the scanning speed and printing height are dynamically adjusted according to the control model to achieve real-time adjustment of the wire height. The specific adjustment method is to adjust the scanning speed and printing height according to the control model (1) (2) so that the microwire height h f Equal to K times the width d of the rectangular opening n , that is, control model (2). By simultaneously increasing the scanning speed and reducing the printing height, the microfilament height h can be reduced. f , improve the printing resolution of the Z axis; vice versa. The experimental results of controlling the wire height using the above method are as follows Figure 7c As shown, the height of the microfilaments extruded from left to right gradually decreases (the three highlighted parts in the figure are the printed microfilaments).

[0150] Change wire width: Figure 8a , Figure 8b As shown, the scanning speed and deflection angle are dynamically adjusted according to the control model to achieve real-time adjustment of the wire width. The specific adjustment method is to adjust the scanning speed v according to the control model (1) (3) s and the rotation motor deflection angle θ, so that the microwire width w f Equal to the rectangular opening length w n The projection in the direction of the scanning speed is the control model (3). By increasing the scanning speed and the deflection angle simultaneously, the microwire width w can be reduced. f , improve the printing resolution of the XY plane; vice versa. The experimental results of controlling the wire width using the above method are as follows Figure 8c As shown, the width of the microfilaments extruded from left to right gradually decreases (the light-colored part in the figure is the printed microfilament).

[0151] Example 5

[0152] Multi-material printing

[0153] The bio-3D printer nozzle structure with decoupled wire height and wire width control of the present invention can be applied to a variety of printing materials and processes after replacing different temperature control modules; by combining multiple nozzle structures of the present invention, multi-material printing is achieved. In the example, one nozzle structure uses an FDM process temperature control module to print polycaprolactone (PCL); the other nozzle structure uses a DIW process temperature control module to print methacrylated gelatin (GelMA); by switching the nozzle structure, multi-material printing is performed, such as Fig. 9 shown.

[0154] As described above, the bio-3D printer nozzle structure and printing method with decoupling control of wire height and wire width of the present invention have the following beneficial effects:

[0155] The present invention achieves decoupling control of the height and width of extruded microfilaments by adjusting the deflection angle, printing height and scanning speed of the rectangular opening nozzle in real time, and can be used for the construction of natural tissue organs.

[0156] The real-time controllable adjustment of the height and width of the printed microfilament has many advantages over the existing technology:

[0157] (1) It can effectively simulate the gradient heterogeneous structure of natural tissues: for example, the gradient pore distribution of bone compaction-spongy bone, which reduces the wire width in large pores and increases the wire width in small pores; for example, the wedge-shaped structure of the meniscus, which reduces the wire height in the inner white area and increases the wire height in the outer red area.

[0158] (2) Variable resolution printing can be achieved, taking into account both printing accuracy and speed: according to the different partition structure characteristics, the printing wire width and wire height can be flexibly controlled. For example, in areas with simple shapes and low precision requirements, the wire height and wire width can be increased to shorten the printing time; in areas with complex shapes and high precision requirements, the wire height and wire width can be reduced to improve the printing quality.

[0159] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A biological 3D printer nozzle structure with decoupling control of wire height and wire width, characterized in that: include: A rotating barrel structure, comprising a rotating barrel for accommodating printing materials, wherein the bottom end of the rotating barrel is conductively connected to a rectangular opening nozzle capable of extruding microfilaments with a rectangular cross-section; the rotating barrel can rotate around the central axis of the barrel to drive the rectangular opening nozzle to rotate a set deflection angle; a push rod structure is sealed and slidably penetrated through the top end of the rotating barrel; and a temperature control system for controlling the printing temperature is connected to the rotating barrel; An extrusion shaft screw module is connected to the push rod structure, and the extrusion shaft screw module provides an axial extrusion force to the printing material through the push rod structure so that the printing material is extruded from the rectangular opening nozzle to form microfilaments; A nozzle support seat, used to support the extrusion shaft screw module and the rotating barrel structure; the nozzle support seat can move along the X-axis, Y-axis, and Z-axis of the spatial coordinate system to change the spatial coordinate position of the rectangular opening nozzle; The control unit, the rotating barrel structure, the extrusion shaft screw module, and the nozzle support seat are all electrically connected to the control unit; the deflection angle, scanning speed and printing height of the rectangular opening nozzle are adjusted by the control unit to decouple the control and adjust the cross-sectional height and width of the microfilament.

2. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 1, characterized in that: The rotating barrel structure also includes a rotating platform and a rotating motor connected to the nozzle support seat, the rotating platform includes a platform connecting part and a platform rotating part, the platform connecting part is fixedly connected to the nozzle support seat, the platform rotating part is connected to the rotating motor through a transmission structure, and the platform rotating part can rotate relative to the platform connecting part under the drive of the rotating motor; the rotating barrel can be connected to the platform rotating part, and the rotating motor is electrically connected to the control part, and the control part drives the platform rotating part, the rotating barrel, and the rectangular opening nozzle to rotate to a set deflection angle by controlling the rotating motor.

3. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 2, characterized in that: A platform through hole is arranged on the rotating platform; the bottom end of the platform rotating part is connected to the coaxial positioning sleeve, the bottom of the coaxial positioning sleeve is connected to the barrel shell, the rotating barrel passes through the platform through hole, the inner cavity of the coaxial positioning sleeve and the inner cavity of the barrel shell, and the rotating barrel is fixedly connected to the barrel shell; a concentric positioning structure for adjusting the coaxiality of the barrel shell and the rotating platform is arranged on the side wall of the coaxial positioning sleeve; the radial interval between the inner wall of the barrel shell and the outer wall of the rotating barrel constitutes a temperature control system accommodating space.

4. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 3, characterized in that: The inner cavity of the coaxial positioning sleeve includes a sleeve through hole extending downward from the top end and a sleeve opening arranged upward from the bottom end, and the aperture size of the sleeve opening is larger than the aperture size of the sleeve through hole; the sleeve opening, the sleeve through hole and the platform through hole are connected; the top end of the barrel shell is embedded in the sleeve opening, and the concentric positioning structure includes correction screws arranged at intervals along the circumferential direction, and one end of the correction screw is against the top side wall of the barrel shell.

5. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 4, characterized in that: A shell flange is provided at the top of the barrel shell, and the shell flange is embedded in the sleeve opening, and the aperture size of the sleeve opening is larger than the outer diameter size of the shell flange; one end of the correction screw abuts against the side wall of the shell flange to adjust the coaxiality of the barrel shell and the rotating platform; a sleeve cover plate is provided under the coaxial positioning sleeve, and the sleeve cover plate is connected to the shell flange by a first connecting screw, and the sleeve cover plate is connected to the coaxial positioning sleeve by a second connecting screw.

6. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 3, characterized in that: The rotating barrel includes a cylindrical portion and a conical portion which are connected to each other. The conical portion is located below the bottom end of the barrel shell, and the cylindrical portion extends upward from the conical portion. The bottom end of the conical portion is connected to the rectangular opening nozzle. A barrel flange is provided on the outer wall of the rotating barrel at the bottom end of the barrel shell, and the barrel flange is connected to the bottom end of the barrel shell by a third connecting screw.

7. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 3, characterized in that: The temperature control system includes a fixed seat and a temperature control module; the fixed seat includes a seat body with a fan-shaped cross-section, and the seat body is inserted into the inner cavity of the platform through hole and the coaxial positioning sleeve; the top of the seat body is exposed from the platform through hole to set a fixed seat flange for connecting to the nozzle support seat, and the fixed seat flange is connected to the nozzle support seat by a fourth connecting screw; an annular seat is set at the bottom end of the seat body, and the temperature control module is connected below the annular seat, and a module through hole is set on the temperature control module, and the temperature control module is set in the accommodating space of the temperature control system; the rotating barrel is inserted through the seat body and the module through hole so that the temperature control system can control the temperature of the rotating barrel.

8. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 2, characterized in that: The push rod structure includes a push rod body, the bottom end of which is sealed and slidably inserted into the rotating barrel from top to bottom, and the push rod body and the rotating barrel are circumferentially fixedly arranged; the top end of the push rod body is connected to a connecting sleeve, the top end of the connecting sleeve is rotatably connected to the bottom end of a connecting seat block through a thrust bearing, and the connecting seat block is connected to the extrusion shaft lead screw module; The push rod body can rotate with the rotating barrel, and the push rod body can push the printing material in the rotating barrel to extrude from the rectangular opening nozzle to form microfilaments under the axial action of the extrusion shaft screw module.

9. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 8, characterized in that: The thrust bearing comprises a tightening ring, a loose ring, a steel ball and a retaining frame; the loose ring is arranged at the bottom end of the connecting seat block; and the tightening ring is arranged at the top end of the connecting sleeve.

10. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 8, characterized in that: The bottom end of the connecting seat block is detachably connected to a positioning column extending downward, and the connecting sleeve is axially fixedly rotatably sleeved on the positioning column.

11. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 10, characterized in that: A stepped hole with a larger diameter at the bottom and smaller diameter at the top is downwardly arranged at the top of the connecting sleeve, a column flange is arranged at the bottom of the positioning column, the positioning column passes through the stepped hole from bottom to top, and the top surface of the column flange abuts against the step surface of the stepped hole.

12. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 11, characterized in that: The bottom end of the connecting sleeve is provided with a T-shaped slot which penetrates radially upward, the top end of the push rod body is provided with a rod flange which can be nested in the T-shaped slot, and the bottom end of the connecting sleeve is connected with a fixing screw which can fix the rod flange.

13. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 8, characterized in that: The top end of the rotating barrel is connected to a rotating positioning buckle that can be buckled on the outside of the push rod body. A limiting protrusion is set on the rotating positioning buckle, and a guide groove is set on the side wall of the push rod body. The guide groove is slidably sleeved on the limiting protrusion to fix the push rod body circumferentially relative to the rotating barrel.

14. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 8, characterized in that: The extrusion axis lead screw module includes an extrusion axis motor, a lead screw and a slider, the lead screw is vertically connected to the nozzle support seat, the top end of the lead screw is connected to the extrusion axis motor, the slider is slidably mounted on the lead screw, the extrusion axis motor drives the lead screw to rotate to drive the slider to move along the lead screw; the connecting seat block is connected to the slider; the extrusion axis motor is electrically connected to the control unit.

15. The biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 1, characterized in that: The nozzle support seat includes a longitudinal support part and a transverse support part, one end of the transverse support part is fixedly connected to one side of the longitudinal support part; the longitudinal support part is located below the transverse support part and is connected to the three-dimensional motion platform; the longitudinal support part is located above the transverse support part and is connected to the extrusion shaft screw module; the rotating barrel structure is connected to the transverse support part.

16. A printing method for a biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in any one of claims 1 to 15, characterized in that: The following steps are involved: Step a, installing the biological 3D printer nozzle structure with decoupling control of wire height and wire width on the printer, and the push rod structure is not installed temporarily; Step b, starting the printer, setting the printing temperature of the temperature control system and keeping the rotating barrel structure warm; Step c, injecting printing material into the rotating barrel and installing the push rod structure; Step d, performing concentric correction on the position of the rectangular opening nozzle; Step e: according to the wire height and wire width requirements of different parts of the model, the model is sliced ​​and a G code instruction is generated, which includes the displacement information of the three-dimensional motion axis, the extrusion axis, and the rotation axis; Step f: During the printing process, the printing parameters are set according to the control model, and the height and width of the cross section of the extruded microfilaments are changed in real time by adjusting the deflection angle, scanning speed and printing height of the rectangular opening nozzle.

17. The printing method of the biological 3D printer nozzle structure with decoupling control of wire height and wire width as claimed in claim 16, characterized in that: The control model in step f includes: h p =K*h f ; Among them, v s is the scanning speed, h p is the printing height, K is the control coefficient, d e is the diameter of the push rod body, v e is the extrusion speed of the push rod body, w f is the microfilament width, h f is the microwire height, d n is the width of the rectangular opening, w n is the length of the rectangular opening, and θ is the angle between the normal direction of the rectangular opening and the scanning speed direction.

Images