Cross-scale support printing device

Abstract

The invention relates to the technical field of biomedical engineering and 3D printing equipment, and discloses a cross-scale support printing device which comprises a material extrusion assembly, a tool head switching assembly and a base assembly which are sequentially connected. The material extrusion assembly comprises a solution extrusion assembly and a thermoplastic extrusion assembly, the solution extrusion assembly and the thermoplastic extrusion assembly are mutually replaceable assemblies, and the solution extrusion assembly and the thermoplastic extrusion assembly are combined and sequenced in the assembly number and the extrusion sequence to adapt to different procedures; the tool head switching assembly is used for achieving switching of the material extrusion assemblies and controlling vertical movement of the selected material extrusion assemblies. The base assembly comprises a mandrel assembly and a plane sliding table assembly. The plane sliding table assembly is used for adjusting plane movement of the mandrel assembly. The mandrel assembly is a base constructed by the polymer support. According to the invention, the structure of a cross-scale stent can be realized, and the stent has biocompatibility and mechanical designability.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical engineering and 3D printing equipment, and in particular to a cross-scale stent printing device. Background Art

[0002] With the advancement of biomaterials science and manufacturing technology, biodegradable polymer materials, especially those represented by polylactic acid (PLA) and polycaprolactone (PCL), have become the core direction of the research and development of the new generation of stents due to their excellent biocompatibility and adjustable degradation cycle. More importantly, the molecular chain designability and thermoplastic processing characteristics of polymer materials enable customized manufacturing of complex microstructures through molding technologies such as 3D printing or electrospinning.

[0003] In the prior art, although melt extrusion additive manufacturing technology has been widely used in the field of polymer luminal stent preparation, it still has certain limitations. For the overhang structure molding of open luminal stents, the existing process needs to rely on the synchronous printing of support materials. After the main body of the stent is constructed, the support structure still needs to be mechanically peeled off or chemically dissolved, which is easy to cause microstructural damage. The improved rotary tube assisted melt extrusion process using a rotating mandrel instead of the traditional flat substrate successfully overcomes the anisotropic mechanical property defects caused by the difference in interlayer orientation in the traditional process through the layer-by-layer deposition of the material melt on the mandrel surface and the circumferential motion synergistic molding, so that the mechanical bearing mechanism of the stent is transformed from the interlayer bonding strength to the bulk material strength control. However, whether it is the stripping of the support structure or the demolding of the metal mandrel, there is a risk of structural integrity being damaged. In addition, the inherent thermodynamic environment of the high-temperature melt deposition process limits the in-situ loading capacity of functional small molecule drugs (such as anti-proliferative rapamycin, anticoagulant heparin, etc.), which significantly restricts the construction of functionalized stents with bioactive surfaces.

[0004] As an important processing method in the field of biomedical engineering, electrospinning technology has been widely used in the preparation of functional polymer stent systems. This technology uses a high-voltage electric field to induce the polymer solution jet to form a nano- to micron-scale fiber network structure. Its significant high specific surface area characteristics can effectively increase the drug loading capacity of the stent. Most active drug molecules can form a uniform spinning precursor with a polymer matrix through solution blending. Under the premise of maintaining the spinnability of the material and the biological activity of the drug, the stable loading and sustained release control of the therapeutic agent in the three-dimensional stent can be achieved. However, the microstructure of the existing electrospinning stent is limited by the self-assembly process of randomly oriented fibers, and the porous film structure is mainly formed by physical entanglement and van der Waals forces. Compared with the artificially designed open-cell grid stent, this naturally formed disordered mesh topology has defects such as insufficient geometric order, broken stress transfer path, and loss of deformation coordination, which makes it difficult to achieve stent diameter adjustment and dynamic mechanical matching during implantation. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention provides a cross-scale stent printing device, which can realize the construction of a cross-scale stent and is a stent with both biocompatibility and mechanical designability.

[0006] To achieve the above object, the present invention provides the following technical solutions: The present invention proposes a cross-scale bracket printing device, comprising a material extrusion component, a tool head switching component and a base component connected in sequence; the material extrusion component comprises a solution extrusion component and a thermoplastic extrusion component, the solution extrusion component and the thermoplastic extrusion component are components that can be replaced with each other, and the solution extrusion component and the thermoplastic extrusion component are combined and sorted in terms of component quantity and extrusion sequence to adapt to different processes; the tool head switching component is used to realize the switching of the material extrusion component and control the vertical movement of the selected material extrusion component; the base component comprises a mandrel component and a plane slide assembly slidably connected to the mandrel component; the plane slide assembly is used to adjust the movement of the mandrel component in the X direction and the Y direction; the mandrel component is a base for constructing the polymer bracket, and the construction of the polymer bracket is completed under the control of the plane position of the plane slide assembly and the vertical displacement of the material extrusion component under the tool head switching assembly.

[0007] Furthermore, the material extrusion component also includes a force driving component; the force driving component is a universal component, one side of which is connected to the solution extrusion component and the thermoplastic extrusion component, and the other side is connected to the tool head switching component, which is used to realize the material extrusion function of the thermoplastic extrusion component and the solution extrusion component; the thermoplastic extrusion component is used to melt the degradable polymer and its blended composite polymer, and extrude the corresponding volume of material onto the core shaft component; the solution extrusion component is used to extrude a preset amount of polymer solution onto the core shaft component.

[0008] Furthermore, the force drive component includes a tool head adapter component and a power component; the tool head adapter component is connected to the tool head switching component to realize the switching of the thermoplastic extrusion component and the solution extrusion component; the power component is an execution unit for the thermoplastic extrusion component and the solution extrusion component to realize the material extrusion function. When an extrusion signal is received, power is applied to the thermoplastic extrusion component and the solution extrusion component to extrude the material onto the core shaft component.

[0009] Furthermore, the force-driven assembly also includes a slider assembly and a tool head covering assembly. The slider assembly is arranged on the outside of the power assembly, and is respectively connected to the power assembly, the thermoplastic extrusion assembly and the solution extrusion assembly to transmit the power of the power assembly to the thermoplastic extrusion assembly and the solution extrusion assembly; the tool head covering assembly is arranged on the periphery of the tool head adapter assembly, the power assembly and the slider assembly, and is used as a shell to cover the tool head adapter assembly, the power assembly and the slider assembly.

[0010] Furthermore, the tool head switching assembly includes a rotation positioning assembly and a lifting execution assembly; the rotation positioning assembly is arranged on the outside of the lifting execution assembly and is slidably connected to at least one group of material extrusion assemblies, and each material extrusion assembly is circumferentially arranged on the rotation positioning assembly. When working, the rotation positioning assembly rotates around the vertical axis of the lifting execution assembly, and is used to be responsible for the switching of each material extrusion assembly (that is, for switching different tool heads); the lower part of the lifting execution assembly is connected to the base assembly, which is used to drive the material extrusion assembly to move up and down, so as to realize the material extrusion assembly to extrude materials at different heights.

[0011] Furthermore, the base assembly is arranged at the lower part of the tool head switching assembly and is rigidly connected to the tool head switching assembly; the mandrel assembly includes a mandrel, which can be displaced in the X direction and the Y direction, and forms a spatial motion coordination relationship with the vertical movement of the tool head switching assembly; the mandrel assembly serves as a platform for preparing the bracket, and the printing device causes the material extruded by the material extrusion assembly to solidify on the surface of the mandrel to form a polymer bracket.

[0012] Furthermore, the base assembly also includes a covering assembly and an electrical assembly; the covering assembly is used to separate the working chamber from the non-working chamber and provide a closed environment; the electrical assembly provides signals and power to all execution components, and is electrically connected to the material extrusion assembly, the tool head switching assembly, the core shaft assembly and the plane slide assembly, respectively, and respectively controls the material extrusion of the material extrusion assembly, controls the tool head switching assembly to achieve the vertical movement of the material extrusion assembly, switches the solution extrusion assembly and the thermoplastic extrusion assembly according to the combination sequence of the solution extrusion assembly and the thermoplastic extrusion assembly, controls the displacement of the core shaft assembly in the X direction and the Y direction, and controls the operation of the plane slide assembly.

[0013] Furthermore, the tool head switching assembly includes a rotation positioning assembly and a lifting execution assembly. The rotation positioning assembly is connected to the material extrusion assembly and to the lifting execution assembly, and can slide up and down on the lifting execution assembly, thereby realizing the vertical displacement of the material extrusion assembly.

[0014] Further, the slider assembly includes a force sensor, and the power assembly includes a motor seat; the thermoplastic extrusion assembly includes a piston, a replaceable piston cylinder, a heating rod, a temperature sensor, a heat-conducting block arranged on the outer ring of the piston cylinder, a nozzle arranged on the lower part of the replaceable piston cylinder and a second positioning bolt; in the thermoplastic material extrusion mode, the upper end of the piston is connected to the force sensor, and the lower end of the piston is connected to the replaceable piston cylinder by sliding up and down under the drive of the slider assembly; the upper part of the heat-conducting block is provided with a heat dissipation fin, and the front end of the heat-conducting block fin is hollowed out and grooved for placing the replaceable piston cylinder; the upper end surface of the lower part of the heat-conducting block is provided with a blind hole for connecting with the replaceable piston cylinder; a plurality of blind holes are provided on the side of the lower part of the heat-conducting block, one blind hole is used to place the temperature sensor, and the remaining blind holes are used to place the heating rod (preferably three, the blind holes on both sides are used to place the heating rods respectively, and the blind hole in the middle is used to place the temperature sensor); the lower end of the second positioning bolt is connected to the heat-conducting block, and the upper end is connected to the motor seat of the power assembly. The heating rod is used to heat the material in the replaceable piston cylinder, the heat conductive block is used to transfer the energy heated by the heating rod to the entire replaceable piston cylinder, and the temperature sensor is used to collect the real-time temperature of the material in the replaceable piston cylinder.

[0015] Furthermore, the thermoplastic extrusion assembly further comprises a rubber ring, which is arranged between the replaceable piston cylinder and the nozzle for sealing. Preferably, there are two second positioning bolts.

[0016] Furthermore, the slider assembly includes a force sensor, and the power assembly includes a motor seat; the solution extrusion assembly includes an injection handle jaw assembly, a syringe clamp jaw assembly, a syringe piston handle, a syringe barrel, a needle and a conductive clip; in the solution material extrusion mode, the upper end of the injection handle jaw assembly is connected to the force sensor of the slider assembly, and the lower end is used to fix the tail end of the syringe piston handle; the syringe barrel clamp jaw assembly is used to fix the handle end of the syringe barrel and is connected to the motor seat of the power assembly; the conductive clip is used to clamp the needle; the needle is screwed to the head of the lower end of the syringe barrel.

[0017] Further, the tool head adapter assembly includes a first adapter seat, a second adapter seat, a positioning end plate, a locking spring, a spring end plate, a locking slider, a spring ejector seat, a first guide rail slider and a second guide rail slider; the first adapter seat is connected to the second adapter seat; there are several positioning end plates, a part of which is connected to the first adapter seat, and another part of which is connected to the second adapter seat (preferably 4 positioning end plates, 2 positioning end plates are connected to the first connecting seat, and 2 positioning end plates are connected to the second connecting seat); an empty groove is opened between the first adapter seat and the second adapter seat, and the empty groove is used to place the locking slider, locking spring, spring end plate and spring ejector seat; The locking slider is a special-shaped structure, provided with a spring circular groove, a locking end and an electrical contact end, the spring circular groove overlaps the locking spring, and the electrical contact end is connected to the spring ejector seat; the locking spring is connected to the spring end plate, and the spring end plate is connected to the first adapter seat and the second adapter seat; under the action of external force, the outer side of the locking slider slides with the inner wall of the empty groove between the first adapter seat and the second adapter seat; the first guide rail slider is connected to the first adapter seat, and the second guide rail slider is connected to the second adapter seat, and the tool head adapter assembly is slidably connected to the vertical guide rail on the rotation positioning assembly through the first guide rail slider and the second guide rail slider thereon to achieve up and down sliding.

[0018] Furthermore, the power assembly includes a reduction stepper motor, a driving gear 106), a first positioning bolt, a tool head PCB board, a gear positioning seat and a motor seat; the lower end of the reduction stepper motor is connected to the motor seat, and the reduction end of the reduction stepper motor is connected to the first gear; there are four first positioning bolts, and the four first positioning bolts pass through the tool head PCB board and are connected to the gear positioning seat, and the first positioning bolt is also connected to the reduction stepper motor; in addition, the first positioning bolt close to the inner side of the rotation center of the rotation positioning assembly is connected to several positioning end plates, the first adapter seat and the second adapter seat of the tool head adapter assembly.

[0019] Furthermore, the slider assembly includes a driven gear, an extrusion screw, a main slider, a slider nut, a third guide rail slider, a fourth guide rail slider, an angular contact bearing, a force sensor and a slider limit switch; the driven gear is fixed to the upper end of the extrusion screw, and the end of the extrusion screw is slidingly connected to the gear positioning seat of the power assembly through an angular contact bearing; the lower end of the extrusion screw is slidingly connected to the motor seat of the power assembly through an angular contact bearing; the slider nut, the force sensor and the slider limit switch are connected to the main slider; the extrusion screw is meshed with the slider nut to drive the main slider to move up and down.

[0020] Furthermore, the tool head covering assembly includes a tool head covering, a first guide rail, a second guide rail and a wire taking-up assembly; the first guide rail and the second guide rail are symmetrically arranged on both sides of the interior of the tool head covering, and the first guide rail and the second guide rail are slidingly connected to the third guide rail slider and the fourth guide rail slider of the slider assembly respectively; the wire taking-up assembly is fixed to the upper front part of the interior of the covering assembly; the tool head covering includes an injection molded shell and an injection molded rib plate arranged on the inner wall of the injection molded shell; the power assembly is fixed inside by the injection molded rib plate of the tool head covering.

[0021] Furthermore, the wire take-up assembly includes a hairspring, a wire take-up turntable, a wire take-up bearing, a wire take-up upper cover and a wire take-up lower cover; the inner end of the hairspring is connected to the wire take-up lower cover, and the outer end of the hairspring is connected to the wire take-up turntable; the outer ring of the wire take-up bearing is connected to the wire take-up turntable, and the inner ring of the wire take-up bearing is connected to the wire take-up upper cover; the wire take-up lower cover is connected to the wire take-up upper cover and the wire take-up upper cover is fixed to the inner side of the front upper part of the tool head covering assembly; the upper end of the wire take-up turntable, the side wall of the wire take-up lower cover and the top surface of the wire take-up upper cover are all provided with wiring harness grooves, allowing the wire of the force sensor to pass through the side wall of the wire take-up lower cover, wrap around the wire take-up turntable, and then pass through the top surface of the wire take-up upper cover to be electrically connected to the tool head PCB board.

[0022] Furthermore, the injection handle clamp assembly includes a first movable claw, a rubber claw head, a movable claw guide rod, a clamp seat, a first top screw and a tension spring; the upper end of the clamp seat is connected to the force sensor, and the lower end is provided with three through holes running through the left and right sides, wherein the front and rear two through holes are used to pass through the two movable claw guide rods, and the through hole in the center is used to pass through the tension spring; the movable claw guide rod is fixed to the clamp seat by the first top screw; there are two first movable claws, and both ends of the tension spring are respectively passed through a first top screw and a first movable claw; the first movable claw is provided with two transverse through holes and a transverse blind hole, the front and rear two transverse through holes are used to pass through the movable claw guide rod, and the tension spring is fixed in the transverse blind hole in the center; the first movable claw can move left and right along the movable claw guide rod.

[0023] Furthermore, the syringe clamp assembly includes an upper clamp seat, a lower clamp seat, a fixing bolt, a second movable jaw, a clamp seat guide rod, a clamp spring and a third positioning bolt; the upper clamp seat is connected to the motor seat of the slider assembly through two third positioning bolts, and is also connected to the lower clamp seat through two fixing bolts; there are two clamp seat guide rods, the two clamp seat guide rods are connected to the upper clamp seat, and are slidably connected to the two through holes of the lower clamp seat; on the lower clamp seat, its left and right extension arms each have four through holes and one blind hole, and the four through holes are slidably connected to the guide rod structure on the second movable jaw; there are two clamp springs in total, for one side of the clamp spring, one end is connected to the blind hole in the extension arm on one side of the lower clamp seat, and the other side is connected to a second movable jaw, and there are two second movable jaws in total.

[0024] Furthermore, the rotation positioning assembly includes a guide rail bracket, a vertical guide rail, a bracket upper end cover, an adapter flange and a hollow rotating platform; there are eight guide rail brackets, and every two guide rail brackets form a group; there are eight vertical guide rails, and every two vertical guide rails are respectively connected to two guide rail brackets in a group; the top ends of the eight guide rail brackets are connected through the bracket upper end cover, and the bottom ends of the guide rail brackets are connected through the adapter flange; the adapter flange is connected to the hollow rotating platform.

[0025] Furthermore, the lifting actuator assembly includes a lifting slide, a first linear bearing, a lifting optical axis, an optical axis end frame, a lifting screw, a screw synchronous wheel, a slide limit switch, a servo, a servo active gear, a selector ejector block, a spring ejector pin, a selector PCB, an upper end cover bearing, a lower end cover bearing, a bearing limit stopper, a lifting base, a lifting synchronous belt and a stepping motor including a synchronous wheel; there are N first linear bearings, and the N first linear bearings are connected to N circumferentially equidistant through holes of the lifting slide ; There are N lifting optical axes, and the N lifting optical axes are slidably connected with N first linear bearings; the upper end of the lifting optical axis is connected to the optical axis end frame, and the lower end is connected to the lifting base; the slide limit switch is connected to the lower part of the optical axis end frame; the lifting screw is meshed and connected with a vertical threaded hole of the lifting slide; the upper end of the lifting screw passes through a vertical through hole of the optical axis end frame and is connected to the inner ring of the upper end cover bearing; the lower end of the lifting screw passes through a vertical through hole of the boss of the lifting base and is connected to the lower end cover The inner ring of the bearing is connected; the outer ring of the upper end cover bearing is connected to the step hole of the upper end cover of the bracket; the lower end cover bearing is connected to the bearing limit block, and the bearing limit block is connected to the lifting base; the screw synchronous wheel is arranged between the boss of the lifting base and the lower end cover bearing, and is connected to the lifting screw; the output axial end face of the stepping motor containing the synchronous wheel is connected to the end face of the lifting base, and the output shaft of the stepping motor containing the synchronous wheel passes through the vertical through hole on the end face of the lifting base, and is meshed with the lifting synchronous belt The servo output end faces downward and is connected to the servo driving tooth; the spring ejector pin is connected to the selector top block, and the servo driving tooth is meshed with the spur gear of the selector top block; a guide rail groove structure is provided on the selector top block, and the guide rail groove structure is slidably connected to the guide rail structure of the lifting slide; the upper end of the selector PCB is connected to the side wall of the servo, and the lower end is connected to the lifting slide; the spring ejector pin is connected to the spring ejector pin seat of the tool head adapter assembly.

[0026] Furthermore, the spindle assembly includes a spindle, a spindle support, a support left end cover, an end cover extension block, a support right end cover, a fixed claw chuck, a movable claw chuck, an active synchronous wheel, a driven synchronous wheel, a spindle synchronous belt, a spindle stepper motor, a first hexagonal sleeve, a ball bearing, a second linear bearing, a hollow stepper motor, a spindle guide slider, a synchronous wheel shielding cover, a tail end shielding cover and a second hexagonal sleeve; the two ends of the spindle are respectively fixed by a movable claw chuck and a fixed claw chuck; the hexagonal handle of the fixed claw chuck is connected to two first hexagonal sleeves, and the two first hexagonal sleeves are connected to the inner rings of two ball bearings. There is also a driven synchronous wheel between the two ball bearings, which is connected to the hexagonal handle of the fixed claw chuck; the hexagonal handle of the movable claw chuck is connected to two second inner hexagonal bushings, and the end faces of the two second inner hexagonal bushings are also connected to each other and are commonly connected to the inner ring of the second linear bearing; the spindle support has two left and right L-shaped bearing seat structures; the left L-shaped bearing seat structure of the spindle support is connected to the outer ring of a ball bearing that constrains the fixed claw chuck, and the outer ring of the other ball bearing is connected to the through hole of the left end cover of the support; the left end cover of the support is connected to the left L-shaped bearing seat structure of the spindle support through the end cover extension block; the spindle stepper motor is connected to the upper part of the left end cover of the support, and the The motor shaft of the spindle stepper motor passes through the opening on the upper part of the left end cover of the support and is connected to the active synchronous wheel, and the active synchronous wheel transmits power to the driven synchronous wheel through the engagement of the spindle synchronous belt; the L-shaped bearing seat structure on the right side of the spindle support is connected to the outer ring of the second linear bearing, and the movable claw chuck is connected to the inner ring of the second linear bearing; the right end cover of the support is connected to the right side step hole of the spindle support; the hollow stepper motor is connected to the slot at the lower right side of the spindle support; the bottom surface of the spindle support is also connected to two spindle guide rail sliders; finally, the synchronous wheel shielding cover is connected to the L-shaped bearing seat structure on the left side of the spindle support, and the tail end shielding cover is connected to the L-shaped bearing seat structure on the right side of the spindle support.

[0027] Furthermore, the planar slide assembly includes an X-direction slide assembly and a Y-direction slide assembly; the X-direction slide assembly is slidably connected to the spindle assembly for adjusting the X-direction displacement of the spindle assembly; the Y-direction slide assembly is slidably connected to the X-direction slide assembly for adjusting the Y-direction displacement of the X-direction slide assembly, thereby adjusting the Y-direction displacement of the spindle assembly.

[0028] Furthermore, the X-direction slide assembly comprises a fixed screw, an X-guide rail, an X-direction slide base, a slide base end cover, a second top screw, a Y-direction sliding rod, a Y-direction sliding nut, a Y-direction slider, an X-direction limit switch and a Y-direction limit switch; there are two end covers of the slide base, which are respectively connected to the left and right ends of the X-direction slide base, and in addition, a hexagonal through hole is opened on the end cover of the slide base, which is connected to the fixed screw to limit the rotation of the screw around the X-axis, and limits the X-direction movement of the fixed screw through the second top screw; the X-direction limit switch is connected to the inner wall of the slide base end cover located on the left side close to the core shaft assembly; the tail end of the Y-direction sliding rod is connected to the X-direction slide base, and the head end of the tail end of the Y-direction sliding rod is respectively connected to the Y-direction sliding nut and the Y-direction limit switch; the upper surface inside the X-direction slide base is connected to the two X-guide rails, and the lower surface of the X-direction slide base is connected to the two Y-direction sliders.

[0029] Furthermore, the Y-direction slide assembly includes a lead screw stepper motor, a slide motor seat, a Y-direction sliding seat and a Y-direction guide rail; the lead screw stepper motor is connected to one end face of the L-shaped structure of the slide motor seat, and the other end face of the L-shaped structure of the slide motor seat is connected to the outer wall of the lifting base; there are a total of two Y-direction guide rails, the lower end faces of the two Y-direction guide rails are connected to the Y-direction sliding seat, and the upper end faces of the two Y-direction guide rails are respectively slidably connected to the two Y-direction sliders.

[0030] Furthermore, the base assembly also includes a covering assembly and an electrical assembly, wherein the covering assembly includes a dust cover, a base upper cover, a working chamber, a base enclosure, a base bottom plate, a filter element, a first PCB sheet metal bracket, a second PCB sheet metal bracket, an air inlet and an air outlet; the base upper cover, the rear partition of the working chamber, the base enclosure and the base bottom plate jointly enclose a non-working chamber area, and an air inlet, an air outlet, a first PCB sheet metal bracket and a PCB second sheet metal bracket are arranged inside; the air outlet and the air inlet are connected to the rear partition of the working chamber , and there are two air outlet ducts, which are symmetrically installed in the side wall of the base shell; the first PCB sheet metal bracket and the second PCB sheet metal bracket are connected to the bottom plate of the base; the core shaft assembly and the plane slide assembly are arranged in the working chamber; the material extrusion assembly and the tool head switching assembly are arranged in the area closed by the dust cover and the base upper cover; there are three filter elements, two of which are respectively arranged in the left and right closed spaces surrounded by the working chamber and the base shell and connected to the side panels with ventilation holes on the left and right of the working chamber, and the remaining filter element is arranged at the entrance of the air inlet duct.

[0031] Furthermore, the electrical components include a main control PCB, a high-voltage DC power supply PCB, an ACDC power supply, an exhaust centrifugal fan, an intake fan, a UVLED lamp group, a working chamber cover, a far-infrared heating tube, a magnetic suction connector male seat, a magnetic suction connector female seat, a touch display screen and an AC power socket; the main control PCB and the high-voltage DC power supply PCB are respectively connected to the first PCB sheet metal bracket A and the second PCB sheet metal bracket; The ACDC power supply is arranged on the bottom plate of the base; there are two exhaust centrifugal fans, which are respectively installed in the left and right closed spaces surrounded by the working chamber and the base enclosure, the blade surface of the exhaust centrifugal fan is connected to the filter element, the back plate surface of the exhaust centrifugal fan is connected to the base enclosure, and the exhaust port of the exhaust centrifugal fan is connected to the rear partition of the working chamber; the intake fan is connected to the inlet of the air inlet, and the air outlet of the intake fan is connected to the filter element; the working chamber cover plate is located at the upper part of the working chamber, and the lower parts of the left and right ends of the working chamber cover plate are connected to the left and right platforms of the working chamber, and a magnetic suction connector female seat is installed at each end of the working chamber cover plate, which is respectively connected to the magnetic suction connector male seat installed on the left and right platforms of the working chamber; the UVLED lamp group is located at the lower part of the working chamber cover plate and is electrically connected to the magnetic suction connector female seat; the far-infrared heating tube is installed in the structure of the upper part of the front side enclosure of the working chamber; the touch display screen is installed at the front opening of the base enclosure and connected to the front structure of the base enclosure; the AC power socket is located at the rear of the base enclosure.

[0032] The present invention combines the current two-scale polymer scaffold manufacturing processes to achieve a cross-scale scaffold structure to construct a scaffold that has both biocompatibility and mechanical designability; at the same time, it combines multi-material printing technology to integrate a variety of electrospinning liquid spinning processes with thermoplastic polymer extrusion processes.

[0033] Compared with the prior art, the present invention provides a cross-scale bracket printing device, which has the following beneficial effects: (1) The present invention has cross-scale system capabilities and adopts a one-stop multi-process integration method, integrating the two processes of melt extrusion and electrospinning, and quickly switching between different processes and materials through a mechanical switching device. The melt printing nozzle is responsible for building the basic structural framework of the scaffold, and its high-precision extrusion capability can ensure the molding of complex geometric shapes; while the electrospinning nozzle forms a gradient pore layer on the surface of the formed structure through nanofiber deposition technology, significantly improving the biological activity and mechanical properties of the material.

[0034] (2) The closed working space brought about by the one-stop integration of the present invention ensures the environmental stability of the bracket preparation during process switching, avoiding contamination or damage to the semi-finished products during the switching of different processes or equipment. At the same time, the one-stop multi-process integration can reduce the multiple installation and disassembly of the semi-finished products due to the adaptation of different processes.

[0035] (3) The present invention adopts a modular design, and the thermoplastic extrusion component and the solution extrusion component are interchangeable and adaptable to different preparation processes. The thermoplastic extrusion component and the solution extrusion component share the same force drive structure, and the replacement of different types of extrusion components can be completed by simply disassembling and assembling the positioning bolts, and both types of extrusion components have a quick-release design. For the thermoplastic extrusion component, the piston cylinder is replaceable, and anti-slip grooves are provided on the upper end. The replaceable piston cylinder can be replaced by hand-tightening to add or replace materials; for the solution extrusion component, the movable jaws of the injection handle clamp assembly and the injection barrel clamp assembly are both provided with springs to assist in fixing the syringe. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a perspective structural schematic diagram of the printing device of the present invention; Figure 2 It is a schematic diagram of the top view of the structure of the printing device of the present invention (only one set of material extrusion components is shown in the figure); Figure 3 It is a schematic diagram of the exploded structure of the printing device of the present invention; Figure 4 For along Figure 2 Schematic cross-sectional view along the AA direction; Figure 5 It is a schematic diagram of the three-dimensional structure after the solution extrusion component and the force driving component are assembled, wherein Figure 5 a and Figure 5 b has a different perspective; Figure 6 It is a three-dimensional structural schematic diagram of the self-tool head covering component perspective force driving component; Figure 7 It is a bottom-up stereoscopic structural schematic diagram of the solution extrusion component and the force driving component after assembly; Figure 8 It is a perspective structural diagram of the tool head cover assembly, wherein Figure 8 a and Figure 8 b has a different perspective; Fig. 9 Schematic diagram of the three-dimensional structure after the mandrel assembly and the flat slide assembly are assembled Figure 1 ; Fig.10 Schematic diagram of the three-dimensional structure after the mandrel assembly and the flat slide assembly are assembled Figure 2 ; Fig.11 It is a three-dimensional structural schematic diagram of the mandrel assembly; Fig.12 Schematic diagram of the main three-dimensional structure after the lifting actuator and the rotating positioning assembly are assembled, where Fig.12 a is a schematic diagram of the main three-dimensional structure. Fig.12 b is a schematic diagram of the rear-view stereoscopic structure; Fig.13is a schematic diagram of the three-dimensional structure of a thermoplastic extrusion component, wherein Fig.13 a is the main view diagram, Fig.13 b is a rear view schematic diagram; Fig.14 It is a schematic diagram of the three-dimensional structure of the solution extrusion component, wherein Fig.14 a is the main view diagram, Fig.14 b is a schematic diagram viewed from above; Fig.15 It is a three-dimensional structural diagram of the rotary positioning component and the lifting actuator component, wherein Fig.15 a is a schematic diagram of the three-dimensional structure of the rotation positioning component; Fig.15 b is a schematic diagram of the three-dimensional structure of the lifting actuator; Fig.16 The exploded structure diagram of the wire take-up device is shown in FIG. Fig.16 a is a left view schematic diagram, Fig.16 b is a schematic diagram viewed from above; Fig.16 c is a schematic diagram of the right side; Fig.17 A partial enlarged schematic diagram of unlocking the extrusion component for the lifting actuator component; Fig.17 a is the locked state, Fig.17 b is the state after unlocking; Fig.18 It is a schematic diagram of the top view of the structure of the printing device of the present invention; Fig.19 for Fig.18 A schematic cross-sectional structural diagram along the BB direction (at this time the printing device of the present invention is in working state).

[0037] The meanings of the reference numerals in the figures are: 1. Material extrusion assembly; 2. Tool head switching assembly; 3. Base assembly; 5. Thermoplastic extrusion assembly; 6. Solution extrusion assembly; 7. Rotation positioning assembly; 8. Lifting actuator assembly 17. Piston; 18. Replaceable piston cylinder; 19. Heating rod; 20. Temperature sensor; 21. Heat conductive block; 22. Rubber ring; 23. Nozzle; 24. Second positioning bolt; 25. Injection handle clamp assembly; 26. Injection cylinder clamp assembly; 27. Syringe piston handle; 28. Syringe cylinder; 29. ​​Needle; 30. Conductive clip; 31. Vertical guide rail; 32. Guide rail bracket; 33. Bracket upper end cover; 34. Adapter flange; 35. Hollow rotating platform; 36. Lifting slide; 37. First linear bearing ;38, lifting optical axis;39, optical axis end frame;40, lifting screw;41, screw synchronous wheel;43, servo;44, servo driving gear;45, selector top block;46, spring ejector;47, selector PCB;48, upper end cover bearing;50, bearing limit stopper;51, lifting base;52, lifting synchronous belt;53, stepping motor with synchronous wheel;54, spindle;55, spindle support;56, support left end cover;57, support right end cover;58, end cover extension block;59, fixed claw chuck;60, movable claw chuck;61, active synchronous wheel;62, driven synchronous wheel;63, spindle synchronous belt;6 4. Spindle stepper motor; 65. First hexagon socket; 66. Ball bearing; 67. Second sliding bearing; 68. Hollow stepper motor; 69. Spindle guide slider; 70. Synchronous wheel shield; 71. Tail end shield; 72- Second hexagon socket; 74. Dust cover; 76. Working chamber; 77. Base shell; 78. Base bottom plate; 79. Filter element; 87. Exhaust centrifugal fan 89. UVLED lamp group 90. Working chamber cover 92. Magnetic connector male seat; 93. Magnetic connector female seat; 96. First adapter seat; 97. Second adapter seat; 98. Positioning end plate; 99. Locking spring; 100. Spring end plate; 101, locking slider; 102, spring ejector seat; 103, first guide slider; 104, second guide slider; 105, reduction stepper motor; 106, first gear; 107, first positioning bolt; 108, tool head PCB board; 109, gear positioning seat; 110, motor seat; 111, second gear; 112, extrusion screw rod; 113, main slider; 114, slider nut; 115, third guide slider; 116, fourth guide slider; 117, angular contact bearing; 118, force sensor; 119, slider limit switch; 120, first guide; 121, second guide; 123, first movable claw; 125, movable claw guide rod; 126, clamping claw seat; 129, upper clamping claw seat; 130, lower clamping claw seat; 131, fixing bolt; 132, second movable claw; 133, clamping claw seat guide rod; 135, third positioning bolt; 136, fixing screw rod; 137, X-direction guide rail; 138, X-direction slide base; 139, slide base end cover;140, second top screw; 141, Y-direction sliding rod; 142, Y-direction sliding nut; 143, Y-direction slider; 146, stepping motor with screw rod; 147, slide motor seat; 148, Y-direction sliding seat; 149, Y-direction guide rail; 150, hairspring; 151, take-up turntable; 153, take-up upper cover; 154, take-up lower cover; 155, sensor signal line; 156, tool head cover. ; DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may also include different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0040] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection content of the present invention.

[0041] Example 1

[0042] like Figures 1 to 4 , Fig.18 and Fig.19 As shown, the cross-scale printing device for a tubular degradable polymer stent provided in this embodiment includes a material extrusion component 1, a tool head switching component 2 and a base component 3.

[0043] like Figures 4 to 8 As shown, the material extrusion assembly 1 includes a force drive assembly 4, a thermoplastic extrusion assembly 5 and a solution extrusion assembly 6. The force drive assembly 4 includes a tool head adapter assembly, a power assembly, a slider assembly and a tool head cover assembly. Figure 5 a. Figure 5 b. Figure 6 as well as Figure 7 As shown, the tool head adapter assembly includes a first adapter seat 96, a second adapter seat 97, a positioning end plate 98, a locking spring 99, a spring end plate 100, a locking slider 101, a spring ejector seat 102, a first guide rail slider 103 and a second guide rail slider 104. The first adapter seat 96 and the second adapter seat 97 are connected through four positioning end plates 98, and the middle slots of the first adapter seat 96 and the second adapter seat 97 form a cavity; the locking slider 101 is installed in the cavity, and a spring circular groove is provided on the locking slider 101, and the spring circular groove overlaps one end of the locking spring 99, and the other end of the locking spring 99 is fixed on the spring end plate 100; the spring ejector seat 102 is fixed to the locking spring 99 by screws; the first guide rail slider 103 and the second guide rail slider 104 are respectively installed on the outside of the first adapter seat 96 and the second adapter seat 97, and are slidably connected with the vertical guide rail 31 of the rotation positioning assembly 7. A mounting through hole for fixed connection with the power assembly is provided at the center of the positioning end plate 98 .

[0044] In a specific implementation of this embodiment, as Figure 6 As shown, the power assembly includes a reduction stepper motor 105, a first gear 106, a second gear 111, a first positioning bolt 107, a tool head PCB board 108, a gear positioning seat 109 and a motor seat 110. The reduction stepper motor 105 is fixed to the motor seat 110 by four first positioning bolts 107, and its output shaft is connected to the first gear 106; the gear positioning seat 109 is installed below the tool head PCB board 108 by bolts, and the tool head PCB board 108 integrates the motor drive circuit and the signal interface; the two first positioning bolts 107 near the inner side of the rotation positioning assembly 7 pass through the mounting through holes of the positioning end plate 98 to fix the power assembly to the tool head adapter assembly.

[0045] In a specific implementation of the present embodiment, the slider assembly includes a first gear 106, an extrusion screw 112, a main slider 113, a slider nut 114, a third guide slider 115, a fourth guide slider 116, an angular contact bearing 117, and a force sensor 118. The second gear 111 is fixed to the top of the extrusion screw 112 by a flat key, and the upper and lower ends of the extrusion screw 112 are connected to the gear positioning seat 109 and the motor seat 110 by an angular contact bearing 117; the main slider 113 is meshed with the extrusion screw 112 by a slider nut 114, and the third guide slider 115 and the fourth guide slider 116 are installed on both sides of the main slider 113, and are slidably matched with the first guide 120 and the second guide 121 of the tool head cover assembly; the force sensor 118 is connected to the bottom of the main slider 113 by a thread, and the slider limit switch 119 is installed on the lower bottom surface of the main slider 113, which is used to calibrate the stroke zero point and safety limit of the main slider 113.

[0046] In a specific implementation of this embodiment, as Figure 8 a and Figure 8 As shown in FIG. 1 b, the tool head cover assembly includes a tool head cover 156 as an outer shell, a first guide rail 120, a second guide rail 121 and a wire take-up assembly. The first guide rail 120, the second guide rail 121 and the wire take-up assembly are all installed in the reinforcement rib slot inside the tool head cover 156.

[0047] In a specific implementation of this embodiment, as Fig.16 a. Fig.16 b and Fig.16 c, the take-up assembly includes a hairspring 150, a take-up turntable 151, a take-up upper cover 153, a take-up lower cover 154, and a sensor signal line 155. The inner end of the hairspring 150 is fixed to the take-up lower cover 154, and the outer end is fixed to the take-up lower cover 151; the sensor signal line 155 is passed through the outer wall opening slot of the take-up lower cover 154, bypasses the step side wall of the take-up turntable 151, passes through the side wall opening slot of the step side wall of the take-up turntable 151, and finally passes through the central opening of the take-up upper cover 153.

[0048] In a specific implementation of this embodiment, as Fig.14 a and Fig.14As shown in FIG. 2 , the solution extrusion assembly 6 includes an injection handle clamp assembly 25, a syringe clamp assembly 26, a syringe and a conductive clip 30; the syringe includes a syringe piston handle 27, a syringe barrel 28 and a needle 29 arranged at the lower end of the syringe barrel 28. The injection handle clamp assembly 25 includes a first movable claw 123, a rubber claw head, a movable claw guide rod 125, a clamp seat 126, a first top screw and a tension spring. The syringe barrel clamp assembly 26 includes an upper clamp seat 129, a lower clamp seat 130, a fixing bolt 131, a second movable claw 132, a clamp seat guide rod 133, a clamp spring and a third positioning bolt 135. The clamp seat 126 of the injection handle clamp assembly 25 is threadedly connected to the lower side of the force sensor 118, and the first movable claw 123 clamps the syringe piston handle 27 along the movable claw guide rod 125 through the tension spring. The second movable claw 132 of the syringe barrel clamp assembly 26 fixes the syringe barrel 28 through the elastic action of the clamp spring. The set bolt 131 passes through the lower clamp seat 130 and is connected to the upper clamp seat 129. By rotating the set bolt 131, the clamping force of the syringe clamp assembly 26 on the syringe barrel 28 can be adjusted; one end of the third positioning bolt 135 is connected to the upper clamp seat 129, and the other end is connected to the motor seat 110, which plays a role in fixing the syringe clamp assembly 26. The conductive clamp 30 includes a clamp end and a handle end. The clamp end clamps the needle 29, and the handle end is connected to the high-voltage DC power supply PCB to provide a positive electrode for the formation of a high-voltage electric field under electrospinning conditions.

[0049] In a specific implementation of this embodiment, the syringe in the solution extrusion component 6 can be a 1mL to 5ml standard syringe, and the spinning solution can be a solution of polylactic acid (PLA), polycaprolactone (PCL), polylactic acid-glycolic acid copolymer (PLGA) with chloroform, hexafluoroisopropanol (HFIP), dichloromethane as solvent or a polyvinyl alcohol (PVA) solution with water as solvent. In addition to the above synthetic polymers, natural polymer solutions such as collagen, chitosan, gelatin, etc. with acetic acid as solvent can also be used as spinning materials.

[0050] In a specific implementation of this embodiment, as Fig.13 a and Fig.13 As shown in FIG. 1 b, the thermoplastic extrusion assembly 5 includes a piston 17, a replaceable piston cylinder 18, a heating rod 19, a temperature sensor 20, a heat conductive block 21, a rubber ring 22, a nozzle 23 and a second positioning bolt 24. The replaceable piston cylinder 18 is fixed to the heat conductive block 21 by threads, the heating rod 19 and the temperature sensor 20 are respectively embedded in the blind holes on both sides of the heat conductive block 21, the nozzle 23 is connected to the bottom of the heat conductive block 21 by threads, and the rubber ring 22 realizes the sealing between the nozzle 23 and the replaceable piston cylinder 18.

[0051] The maximum operating temperature of the thermoplastic extrusion component 5 does not exceed 300°C, and the thermoplastic polymer used can be polylactic acid PLA (including PLLA, PLDA), polyglycolic acid PGA, polycaprolactone PCL, polylactic acid-glycolic acid copolymer PLGA, polydioxanone PDS, polytrimethylene carbonate PTMC, polyurethane PU, and blends of the above materials with degradable metals (magnesium-based alloys, zinc-based alloys, iron-based alloys), metal organic frameworks, metal polyphenols and other materials.

[0052] In a specific implementation of this embodiment, as Fig.12 and Fig.15 As shown, the tool head switching assembly 2 includes a rotation positioning assembly 7 and a lifting actuator assembly 8, and the rotation positioning assembly 7 includes a vertical guide rail 31, a guide rail bracket 32, a bracket upper end cover 33, an adapter flange 34 and a hollow rotating platform 35. There are eight guide rail brackets 32, which are divided into four groups, each group is connected by a vertical guide rail 31, the top end is fixed by the bracket upper end cover 33, and the bottom end is bolted to the hollow rotating platform 35 through the adapter flange 34. The hollow rotating platform 35 can rotate.

[0053] In a specific implementation of this embodiment, as Fig.12 As shown, the lifting actuator assembly 8 includes a lifting slide 36, a sliding bearing 37, a lifting optical axis 38, an optical axis end frame 39, a lifting screw 40, a screw synchronous wheel 41, a slide limit switch, a steering gear 43, a steering gear driving gear 44, a selector top block 45, a spring top pin 46, a selector PCB 47, an upper end cover bearing 48, a lower end cover bearing 49, a bearing limit stopper 50, a lifting base 51, a lifting synchronous belt 52 and a stepping motor with a synchronous wheel 53. The top end of the lifting optical axis 38 is fixed by the optical axis end frame 39, and the bottom end is inserted into the three holes of the lifting base 51. The lifting slide 36 is slidably connected to the lifting optical axis 38 through six first linear bearings 37, and the threads in the lifting slide 36 are meshed with the lifting screw 40, driving the rotation of the steering gear driving gear 44 through the steering gear 43, and the locking slider 101 is driven by the straight tooth structure of the locking slider 101 to slide along the guide groove structure on the lifting slide 36. The top of the lifting screw is constrained on the optical axis end frame 39 through the upper end cover bearing 48, and the bottom forms a transmission relationship with the stepping motor 53 including the synchronous wheel through the screw synchronous wheel 41 and the lifting synchronous belt 52.

[0054] like Fig.17 As shown, Fig.17 a and Fig.17 b is a process state diagram of the unlocking and extruding component of the lifting actuator component 8. Fig.17a is the material extrusion assembly 1 in a locked state. In this state, the material extrusion assembly 1 is fixed on the guide rail 31 and cannot move up and down because the locking slider 101 is stuck in the pre-slotted groove of the vertical guide rail 31. At this moment, in the lifting actuator 8, the selector top block 45 is stored in the lifting slide 36, and the spring ejector pin 46 does not contact the spring ejector pin seat 101. After receiving the execution signal from the selector PCB 47, the servo 43 moves the selector top block 45 to the left direction shown in the figure, and the top structure of the selector top block 45 is inserted into the upper surface of the empty groove between the first adapter seat 96 and the second adapter seat 97 in the tool head adapter assembly. As the selector top block 45 is gradually inserted, the locking slider 101 is pushed to the left by the selector top block 45, and the spring ejector pin 46 and the spring ejector pin seat 101 are in contact. Fig.17 b indicates that the material extrusion assembly 1 is in an unlocked state. When the selector top block 45 reaches the predetermined opening stroke, the locking slider 101 is disengaged from the pre-grooved connection with the vertical guide rail 31, and the vertical movement of the material extrusion assembly 1 is transferred to the lifting slide 36 through the selector top block 4; at this time, under the action of the locking spring 99, the spring ejector pin 46 always keeps in contact with the spring ejector pin seat 101, so the electrical signal and power supply from the selector PCB47 can be transmitted to the tool head PCB board 108 to complete the subsequent actuation of each execution unit in the material extrusion assembly 1.

[0055] In a specific implementation of this embodiment, the base assembly 3 includes a spindle assembly and a flat slide assembly. Figures 9 to 11 As shown, the spindle assembly includes a spindle 54, a spindle support 55, a support left end cover 56, a support right end cover 57, an end cover extension block 58, a fixed claw chuck 59, a movable claw chuck 60, an active synchronous wheel 61, a driven synchronous wheel 62, a spindle synchronous belt 63, a spindle stepper motor 64, a first hexagon socket 65, a ball bearing 66, a second linear bearing, a hollow stepper motor 68, a spindle guide slider 69, a synchronous wheel shielding cover 70, a tail end shielding cover 71 and a second hexagon socket 72. The two ends of the spindle 54 are clamped by the fixed claw chuck 59 and the movable claw chuck 60. The long handle end of the fixed claw chuck 59 is firstly embedded in the first hexagon socket 65, and then connected to the spindle support 55 through the ball bearing 66. The long handle end of the movable claw chuck 60 is firstly embedded in the second hexagon socket 72, and then axial sliding is achieved through the second linear bearing. The mandrel stepper motor 64 drives the driven synchronous wheel 62 through the active synchronous wheel 61 and the mandrel synchronous belt 63, driving the mandrel 54 to rotate. The hollow stepper motor 68 is installed in the slot on the lower right side of the mandrel support 55; two mandrel guide sliders 69 are also fixed on the bottom surface of the mandrel support 55; the synchronous wheel shielding cover 70 is connected to the L-shaped bearing seat structure on the left side of the mandrel support 55, and the tail end shielding cover 71 is assembled on the L-shaped bearing seat structure on the right side of the mandrel support 55. The synchronous wheel shielding cover 70 and the tail end shielding cover 71 are used to ensure the cleanliness of the transmission parts and moving parts that are difficult to clean in the electrospinning working condition.

[0056] In a specific implementation of this embodiment, as Fig. 9 and Fig.10 As shown, the plane slide assembly includes an X-direction slide assembly and a Y-direction slide assembly, wherein the X-direction slide assembly also includes a fixed screw 136, an X-direction guide rail 137, an X-direction slide base 138, a slide base end cover 139, a second top screw 140, a Y-direction sliding rod 141, a Y-direction sliding nut 142, a Y-direction slider 143, an X-direction limit switch and a Y-direction limit switch. The X-direction slide assembly is rigidly connected to the slide base end cover 139 through a fixed screw 136, and the two ends of the screw 136 are constrained for axial rotation by the second top screw 140 in the end cover; two X-direction guide rails 137 are fixed in parallel to the upper surface of the X-direction slide base 138, and slide with the Y-direction slider 143 to achieve planar motion; the tail end of the Y-direction sliding rod 141 is fixed to the X-direction slide base 138, and the head drives the slide to move along the Y-axis through the Y-direction sliding nut 142; the X-direction limit switch and the Y-direction limit switch are respectively installed on the base end cover and the sliding rod head for stroke end protection.

[0057] In a specific implementation of this embodiment, the Y-direction slide assembly includes a screw-containing stepper motor 146, a slide motor seat 147, a Y-direction slide seat 148, and a Y-direction guide rail 149. The Y-direction slide assembly is driven by a screw-containing stepper motor 146, and the motor is vertically fixed on the L-shaped bracket of the slide motor seat 147; the Y-direction guide rail 149 is arranged in parallel in the slot on the Y-direction slide seat 148; and the range of motion is controlled by the Y-direction limit switch.

[0058] In a specific implementation of the present embodiment, the base assembly 3 also includes a covering assembly and an electrical assembly. The covering assembly includes a dust cover 74, a base upper cover, a working chamber 76, a base enclosure 77, a base bottom plate 787, a filter element 79, a first PCB sheet metal bracket, a second PCB sheet metal bracket, an air inlet and an air outlet. The dust cover 74 of the covering assembly is sealed with the base upper cover and the working chamber 76, and the non-working chamber 76 is formed by the inner side of the base enclosure 77, the outer side of the side wall of the working chamber 76 and the base bottom plate 78; the air inlet and the air outlet are respectively integrated with a filter element 79 and an exhaust centrifugal fan 87, which are directly fixed on the side wall of the rear cavity of the working chamber 76 to form a directional airflow circulation; the first PCB sheet metal bracket and the second PCB sheet metal bracket are fixed on the base bottom plate 78 with sheet metal folding edges, respectively carrying the main control PCB and the high-voltage DC power supply PCB.

[0059] The electrical components include a main control PCB, a high-voltage DC power supply PCB, an ACDC power supply, an exhaust centrifugal fan 87, an intake fan, a UVLED lamp group 89, a working chamber cover 90, a far-infrared heating tube, a magnetic connector male seat 92, a magnetic connector female seat 93, a touch screen and an AC power socket. The main control PCB and the high-voltage DC power supply PCB of the electrical components are fixed to the first PCB sheet metal bracket and the second PCB sheet metal bracket respectively by insulating bolts, and are connected to external sensors and actuators through FPC cables; the exhaust centrifugal fan 87 is symmetrically arranged on the left and right side walls of the working chamber 76, and cooperates with the filter element 79 to maintain a clean environment; the far-infrared heating tube is embedded in the front wall of the working chamber 76, the UVLED lamp group 89 and the magnetic connector female seat 93 are installed on the lower surface of the working chamber cover 90, the UVLED lamp group 89 provides sterilizing ultraviolet radiation, and the far-infrared heating tube temperature control heat source; the touch screen is embedded in the front opening of the base enclosure 77, and communicates with the main control PCB through cables.

[0060] like Figures 1 to 17 As shown, the stent preparation principle of the cross-scale printing device for tubular degradable polymer stents provided in this embodiment is as follows: (1) Preparation: Before installing the material extrusion assembly 1, cover the working chamber cover plate 90 and the dust cover 74, turn on the UVLED lamp group 89 to irradiate the working chamber 76 for sterilization for thirty minutes. After the sterilization work is completed, open the dust cover 74, and install the extrusion assemblies with different filling materials in sequence according to the requirements of the stent preparation (1. Solution extrusion assembly 6 filled with PVA aqueous solution (PVA solution concentration 8wt%, solvent is deionized water), 2. Thermoplastic extrusion assembly 5 filled with PCL powder, 3. Solution extrusion assembly 6 filled with dichloromethane solution of PCL, 4. Solution extrusion assembly 6 filled with hexafluoroisopropanol solution of PLGA loaded with levofloxacin). Install the above four extrusion assemblies on the force drive assembly 4 respectively, and close the dust cover 74 after the material extrusion assembly 1 is installed. Enable the touch screen and set the working parameters of each material extrusion component: set the voltage of the first sacrificial layer PVA spinning layer to 20kV and the spinning solution flow rate to 1.2mL / h; set the second layer PCL thermoplastic extrusion temperature to 80℃; set the working voltage of the third layer PCL spinning layer to 15kV and the spinning solution flow rate to 0.5mL / h; set the working voltage of the fourth layer drug-carrying layer to 25kV and the spinning solution flow rate to 0.8mL / h. After the parameters are set, start the preparation of the stent.

[0061] (2) Material extrusion component selection: The main control PCB in the equipment sends an instruction, and the rotating positioning component 7 rotates the solution extrusion component 6 filled with PVA aqueous solution to just above the opening of the working chamber cover 90, and the lifting slide 36 in the lifting execution component 8 moves to the preset position. The selector top block 45 is inserted into the slot of the tool head adapter component of the corresponding material extrusion component 1 along the guide groove of the lifting slide 36 according to the instruction. After the tool head PCB board 108 establishes communication with the selector PCB47, the core shaft assembly reaches the specified position under the coordinated movement of the plane slide assembly, and the lifting slide 36 drives the target material extrusion component 1 to move downward to just above the core shaft 54 ​​in the working chamber 76, and the execution of the instruction for the solution extrusion component 6 to switch to the working position is completed.

[0062] (3) Electrospinning mode: Switch to the electrospinning mode, and the exhaust centrifugal fan 87 starts working. The high-voltage power supply PCB85 receives the instruction to provide a high-voltage positive electrode for the conductive clip 30, and the power component drives the slider component to push the syringe piston handle 27 to move and extrude the spinning solution. Under the action of the electric field force, a layer of PVA nanofiber membrane with a thickness of 50μm is electrospun and deposited on the surface of the metal core shaft as a sacrificial layer. After spinning, it is left to stand for 30 minutes to allow the fiber network to fully dry.

[0063] (4) Material extrusion component recovery and switching: When the electrospinning is completed, the main control PCB in the device sends a command, and the lifting slide 36 in the lifting actuator assembly 8 drives the material extrusion assembly 1 to lift. When the predetermined locking height is reached, the selector top block 45 retreats along the guide groove of the lifting slide 36 according to the command, and the locking slider 101 in the tool head adapter assembly is pushed by the locking spring 99 to snap into the pre-opened groove of the guide bracket 32 ​​again to complete the locking of the material extrusion assembly 1.

[0064] The main control PCB in the equipment sends instructions again, and the rotating positioning component 7 rotates the extrusion component equipped with the PCL powder thermoplastic extrusion component 5 to be just above the opening of the working chamber cover 90, and the lifting slide 36 in the lifting execution component 8 moves to a specific position. The selector top block 45 is inserted into the groove in the tool head adapter component of the corresponding material extrusion component 1 along the guide groove of the lifting slide 36 according to the instruction. After the tool head PCB board 108 establishes communication with the selector PCB47, the lifting slide 36 drives the target material extrusion component 1 to move downward to just above the core shaft 54 ​​in the working chamber 76, and the execution of the instruction for the thermoplastic extrusion component 5 to switch to the working position is completed.

[0065] (5) Thermoplastic extrusion mode: Switch to the thermoplastic extrusion mode, the air intake fan is turned on and the exhaust centrifugal fan 87 is kept running. The PCL "ring" matrix structure with an outer diameter of 3.0 mm and a wall thickness of 200 μm is printed on the surface of the PVA film using a melt extrusion process. The mandrel rotates at a constant speed of 15 rpm and cooperates with the X / Y plane slide to form a ring support unit with a spacing of 1.0 mm.

[0066] (6) Material extrusion component recovery and switching: After the substrate printing is completed, the main control PCB in the device sends a command, and the lifting slide 36 in the lifting actuator assembly 8 drives the material extrusion assembly 1 to lift. When the predetermined locking height is reached, the selector top block 45 retreats along the guide groove of the lifting slide 36 according to the command, and the locking slider 101 in the tool head adapter assembly is pushed by the locking spring 99 to snap into the pre-opened groove of the guide bracket 32 ​​again to complete the locking of the material extrusion assembly 1.

[0067] The main control PCB in the equipment sends instructions again, and the rotating positioning component 7 rotates the extrusion component of the dichloromethane solution extrusion component 6 loaded with PCL to just above the opening of the working chamber cover 90, and the lifting slide 36 in the lifting execution component 8 moves to a specific position. The selector top block 45 is inserted into the groove in the tool head adapter component of the corresponding material extrusion component 1 along the guide groove of the lifting slide 36 according to the instruction. After the tool head PCB board 108 establishes communication with the selector PCB47, the lifting slide 36 drives the target material extrusion component 1 to move downward to just above the core shaft 54 ​​in the working chamber 76, and the execution of the instruction for the solution extrusion component 6 to switch to the working position is completed.

[0068] (7) Electrospinning mode: Switch to the third-layer electrospinning membrane working mode, turn off the air intake fan and keep the exhaust centrifugal fan 87 running, and use the near-field direct writing electrospinning mode to deposit the PCL nanofiber "bridge" connection structure between adjacent PCL rings. The fiber diameter is controlled at 5-10μm to provide flexible deformation ability.

[0069] Then, the far-infrared heating tube is started to raise the temperature of the working chamber 76 to 70°C (slightly higher than the glass transition temperature of PCL 60°C), and the temperature is kept for 10 minutes to promote the interface fusion of the molten extrusion layer and the electrospinning layer through molecular chain diffusion.

[0070] (8) Material extrusion component recovery and switching: After the preparation of the third layer of electrospinning membrane is completed, the main control PCB in the equipment sends a command, and the lifting slide 36 in the lifting actuator assembly 8 drives the material extrusion assembly 1 to lift. When the predetermined locking height is reached, the selector top block 45 retreats along the guide groove of the lifting slide 36 according to the command, and the locking slider 101 in the tool head adapter assembly is pushed by the locking spring 99 to snap into the pre-opened groove of the guide bracket 32 ​​again to complete the locking of the material extrusion assembly 1.

[0071] The main control PCB in the equipment sends instructions again, and the rotating positioning component 7 rotates the extrusion component of the hexafluoroisopropanol solution extrusion component 6 containing PLGA loaded with levofloxacin to just above the opening of the working chamber cover 90, and the lifting slide 36 in the lifting execution component 8 moves to a specific position. The selector top block 45 is inserted into the groove in the tool head adapter component of the corresponding material extrusion component 1 along the guide groove of the lifting slide 36 according to the instruction. After the tool head PCB board 108 establishes communication with the selector PCB47, the lifting slide 36 drives the target material extrusion component 1 to move downward to just above the core shaft 54 ​​in the working chamber 76, and the execution of the instruction for the solution extrusion component 6 to switch to the working position is completed.

[0072] (9) Electrospinning mode: Switch to the fourth layer electrospinning membrane working mode, the exhaust centrifugal fan 87 keeps running, and a drug-loaded fiber layer with a thickness of 30 μm and a fiber diameter of 200-500 nm is formed on the outer surface of the stent by electrospinning to provide a high specific surface area drug sustained-release interface.

[0073] (10) Material extrusion component recycling: After the fourth layer of electrospinning membrane is prepared, the main control PCB in the equipment sends a command, and the lifting slide 36 in the lifting actuator assembly 8 drives the material extrusion assembly 1 to lift. When the predetermined locking height is reached, the selector top block 45 retreats along the guide groove of the lifting slide 36 according to the command, and the locking slider 101 in the tool head adapter assembly is pushed by the locking spring 99 to snap into the pre-opened groove of the guide bracket 32 ​​again to complete the locking of the material extrusion assembly 1.

[0074] (11) Stent removal: After the material extrusion assembly 1 is locked in the rotation positioning assembly 7, the mandrel assembly reaches the stent removal position under the coordinated movement of the plane slide assembly, the dust cover 74 and the working chamber cover 90 are opened, the fixed claw chuck 59 and the movable claw chuck 60 are loosened, and the mandrel 54 containing the multi-layer polymer stent is removed. The mandrel 54 is placed in deionized water and soaked for thirty seconds, and the PVA sacrificial layer is dissolved by the tissue fluid to realize the non-destructive demoulding of the mandrel.

[0075] It should be noted that, in this application, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements.

[0076] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A cross-scale bracket printing device, characterized in that: It comprises a material extrusion component, a tool head switching component and a base component which are connected in sequence; the material extrusion component comprises a solution extrusion component and a thermoplastic extrusion component, the solution extrusion component and the thermoplastic extrusion component are components which can be replaced with each other, and the solution extrusion component and the thermoplastic extrusion component are combined and arranged in terms of component quantity and extrusion sequence to adapt to different processes; the tool head switching component is used to realize the switching of the material extrusion component and control the vertical movement of the selected material extrusion component; the base component comprises a mandrel component and a plane slide component which is slidably connected to the mandrel component; the plane slide component is used to adjust the movement of the mandrel component in the X direction and the Y direction; the mandrel component is the base for constructing the bracket, and the construction of the bracket is completed under the control of the plane position of the plane slide component and the vertical displacement of the material extrusion component under the tool head switching component.

2. A cross-scale bracket printing device according to claim 1, characterized in that: The material extrusion assembly also includes a force driving assembly; the force driving assembly is a universal assembly, one side of which is connected to the solution extrusion assembly and the thermoplastic extrusion assembly, and the other side is connected to the tool head switching assembly, and is used to realize the material extrusion function of the thermoplastic extrusion assembly and the solution extrusion assembly; the thermoplastic extrusion assembly is used to melt the degradable polymer and its blended composite polymer, and extrude the corresponding volume of material onto the core shaft assembly; the solution extrusion assembly is used to extrude a preset quantitative polymer solution onto the core shaft assembly.

3. The cross-scale bracket printing device according to claim 1, characterized in that: The force drive component includes a tool head adapter component and a power component; the tool head adapter component is connected to the tool head switching component to realize the switching between the thermoplastic extrusion component and the solution extrusion component; the power component is an execution unit for the thermoplastic extrusion component and the solution extrusion component to realize the material extrusion function. When an extrusion signal is received, power is applied to the thermoplastic extrusion component and the solution extrusion component to extrude the material onto the core shaft component.

4. A cross-scale bracket printing device according to claim 3, characterized in that: The force-driven assembly also includes a slider assembly and a tool head covering assembly. The slider assembly is arranged on the outside of the power assembly and is respectively connected to the power assembly, the thermoplastic extrusion assembly and the solution extrusion assembly to transmit the power of the power assembly to the thermoplastic extrusion assembly and the solution extrusion assembly. The tool head covering assembly is arranged on the periphery of the tool head adapter assembly, the power assembly and the slider assembly to serve as a shell to cover the tool head adapter assembly, the power assembly and the slider assembly.

5. The cross-scale bracket printing device according to claim 1, characterized in that: The tool head switching assembly includes a rotation positioning assembly and a lifting execution assembly; the rotation positioning assembly is arranged on the outside of the lifting execution assembly and is slidably connected to at least one group of material extrusion assemblies, and each material extrusion assembly is circumferentially arranged on the rotation positioning assembly. When working, the rotation positioning assembly rotates around the vertical axis of the lifting execution assembly to be responsible for the switching of each material extrusion assembly; the lower part of the lifting execution assembly is connected to the base assembly to drive the material extrusion assembly to move up and down, so as to realize the material extrusion assembly to extrude materials at different heights.

6. The cross-scale bracket printing device according to claim 1, characterized in that: The base assembly is arranged at the lower part of the tool head switching assembly; the mandrel assembly includes a mandrel, which can be displaced in the X direction and the Y direction, and forms a spatial motion coordination relationship with the vertical movement of the tool head switching assembly; the mandrel assembly serves as a platform for preparing the bracket, and the printing device causes the material extruded by the material extrusion assembly to solidify on the surface of the mandrel to form a bracket.

7. The cross-scale bracket printing device according to claim 1, characterized in that: The base assembly also includes a covering assembly and an electrical assembly; the covering assembly is used to separate the working chamber from the non-working chamber and provide a closed environment; the electrical assembly provides signals and power to all actuators, and is electrically connected to the material extrusion assembly, the tool head switching assembly, the mandrel assembly and the plane slide assembly, respectively, and controls the material extrusion of the material extrusion assembly, controls the tool head switching assembly to achieve the vertical movement of the material extrusion assembly, switches the solution extrusion assembly and the thermoplastic extrusion assembly according to their combination sequence, controls the displacement of the mandrel assembly in the X direction and the Y direction, and controls the operation of the plane slide assembly.

8. The cross-scale bracket printing device according to claim 1, characterized in that: The tool head switching assembly includes a rotation positioning assembly and a lifting execution assembly. The rotation positioning assembly is connected to the material extrusion assembly and the lifting execution assembly, and can slide up and down on the lifting execution assembly to achieve vertical displacement of the material extrusion assembly.

9. The cross-scale bracket printing device according to claim 4, characterized in that: The slider assembly includes a force sensor, and the power assembly includes a motor seat; the thermoplastic extrusion assembly includes a piston, a replaceable piston cylinder, a heating rod, a temperature sensor, a heat-conducting block arranged on the outer ring of the piston cylinder, a nozzle and a second positioning bolt arranged on the lower part of the replaceable piston cylinder; in the thermoplastic material extrusion mode, the upper end of the piston is connected to the force sensor, and the lower end of the piston is connected to the replaceable piston cylinder in an up and down sliding manner under the drive of the slider assembly; the upper part of the heat-conducting block is provided with a cooling fin, and the front end of the heat-conducting block fin is hollowed out and grooved for placing the replaceable piston cylinder; the upper end surface of the lower part of the heat-conducting block is provided with a blind hole for connecting with the replaceable piston cylinder; a plurality of blind holes are provided on the side of the lower part of the heat-conducting block, one blind hole is used to place the temperature sensor, and the remaining blind holes are used to place the heating rod; the lower end of the second positioning bolt is connected to the heat-conducting block, and the upper end is connected to the motor seat of the power assembly.

10. The cross-scale bracket printing device according to claim 4, characterized in that: The slider assembly includes a force sensor, and the power assembly includes a motor seat; the solution extrusion assembly includes an injection handle jaw assembly, a syringe clamp jaw assembly, a syringe piston handle, a syringe barrel, a needle and a conductive clip; in the solution material extrusion mode, the upper end of the injection handle jaw assembly is connected to the force sensor of the slider assembly, and the lower end is used to fix the tail end of the syringe piston handle; the syringe barrel clamp jaw assembly is used to fix the handle end of the syringe barrel and is connected to the motor seat of the power assembly; the conductive clip is used to clamp the needle; the needle is screwed to the head of the lower end of the syringe barrel.

Images