Human body implantation type 3D printing wire preparation device

Abstract

The utility model relates to a human body implantation type 3D printing wire preparation device which comprises a feeding machine, a control device, a conveying device, an extrusion device, a shaping and cooling device, a traction device, an annealing device and a cutting and winding device, the feeding machine is connected with the conveying device, and the conveying device comprises a machine barrel, a double-screw mechanism and a temperature sensor. The conveying device is in threaded connection with the extrusion device, the extrusion device comprises a die body, a sprue spreader, a die ring, a mouth die and a mouth die pressing ring, and the annealing device comprises a constant-temperature water tank and a tension regulation and control roller device. According to the utility model, the coating is prepared in the extrusion channel, so that the problems of mouth die abrasion, surface roughness increase and unsmooth material flow caused in the extrusion process of materials are solved, and the strength and toughness of wires are improved through the annealing process.

Description

Technical Field

[0001] This utility model belongs to the field of extruder technology, specifically relating to a device for preparing implantable 3D printing filaments. Background Technology

[0002] Throughout the history of medical development, advancements in surgical techniques have led to an increasing demand for materials used to repair human tissues and organs. Traditional treatment methods have limitations in addressing fractures and tissue defects. The emergence of implantable wires has been developed to better stabilize fracture sites. For example, in fracture surgery, wires can provide stable fixation, aiding in better bone healing. Similarly, in soft tissue repair and dental implants, wires are needed to perform suturing and support functions, creating favorable conditions for tissue repair.

[0003] With the continuous development of 3D printing technology, researchers have begun to explore the use of filaments as raw materials for 3D printing. The emergence of Fused Deposition Modeling (FDM) technology has laid the foundation for filament 3D printing. Combining 3D printing with biomaterials allows for the creation of personalized implants tailored to individual patient needs, thereby improving treatment outcomes. Against this backdrop, PLA, as a biocompatible and biodegradable material, has attracted widespread attention. Human cell scaffolds printed using PLA can effectively promote the growth and repair of human tissues and can be used to prepare tissue engineering scaffolds, surgical aids, and biodegradable medical devices.

[0004] However, current extruders used for preparing filaments suffer from die wear due to the relative movement between the material and the die wall during extrusion. This wear leads to reduced dimensional accuracy, uneven wall thickness, and increased surface roughness in the filaments. Furthermore, a worn die can obstruct material flow, impacting production efficiency. In addition, implantable filaments require sufficient strength to withstand tensile and compressive forces depending on the implantation site and intended use. The filaments also need appropriate flexibility; for example, in soft tissue or vascular repair, overly stiff filaments may damage the tissue, necessitating suitable flexibility to conform to tissue shape and movement. Existing implantable filaments, through the use of high-performance materials, material modification and innovation, and optimized printing technology, can produce implants with excellent toughness, meeting the requirements of human implants, but this increases production costs. This invention increases the strength and toughness of filament by using an annealing process. Compared with the prior art, annealing can improve the strength and toughness, solve the inherent defects of the extrusion process, promote molecular chain relaxation and rearrangement, reduce orientation effect, and improve transverse toughness and dimensional stability (e.g., the bending strength of 3D printed PLA filament increases by 30% after annealing). Annealing can be used as an independent process after extrusion, seamlessly connecting with existing production lines. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a device for preparing implantable 3D printed filaments. This device features a coating on the die ejection section to improve its wear resistance, and an annealing process is added after the filaments are extruded to resolve the problems of insufficient strength and toughness of the filaments mentioned in the background.

[0006] This invention provides a device for preparing filaments for human implantable 3D printing, including a feeder, a control device, a conveying device, an extrusion device, a shaping and cooling device, a traction device, an annealing device, and a cutting and winding device. The feeder is a precision feeding device that ensures material is supplied to subsequent equipment at a set flow rate within a certain time, thereby effectively controlling the uniformity of the extruded filament diameter. The feeder is connected to one end of the conveying device, which includes a barrel, a twin-screw mechanism, and a temperature sensor. The control device is connected to the feeder and the conveying device to control the rotational speed, screw temperature, and material supply speed of the twin-screw mechanism. A temperature sensor is installed at the end of the conveying device to accurately measure the melt temperature and control product quality. The other end of the conveying device is connected to one end of the extrusion device, which includes a die body, a die nozzle, and a separator. The extrusion device comprises a flow cone, a die ring, and an orifice die ring. One end of the extrusion device is connected to one end of a shaping and cooling device, which includes a cooling water tank, a water circulation system, and rollers. The filament extruded from the extrusion device is driven by transmission rollers within the water tank, continuously passing through the tank for cooling and shaping. The other end of the shaping and cooling device is equipped with a traction device, the core component of which is a synchronous pulley. The pulley's movement drives the filament to be continuously fed in. The other end of the traction device is connected to an annealing device, which includes a constant-temperature water tank with temperature control functionality. Inside the constant-temperature water tank are two sets of adjustable tension regulating rollers, allowing for flexible adjustment of the filament's tension to meet the temperature and mechanical requirements of the annealing process. The cutting and winding device includes a cutter and a spool. Finally, the filament is cut to a fixed length by the cutter and collected by the spool for subsequent processing and use.

[0007] The extrusion device has an external thread at one end of the die body and an internal thread at the other end of the conveying device. The extrusion device and the conveying device are securely connected by the threads. A die ring is provided above the die body, and the die ring, die, and die body are fixedly connected by screws and pins. A die pressure ring is provided above the die, and the die pressure ring and die are connected by screws and pins. The flow divider cone of the extrusion device is located in the central area of ​​the die body and is connected to the die body by screws and pins. A flow divider channel is formed between the outer surfaces of the two ends of the flow divider cone and the inner surface of the die body to ensure uniform material distribution. The flow divider cone has eight flow channel holes evenly distributed in a circle. Four detachable extrusion channel blocks are arranged side by side in the center of the die. The inner wall of the extrusion channel block is coated with polytetrafluoroethylene to reduce the friction between the material flow and the channel and extend the service life of the die. The inner wall diameter of two extrusion channel blocks is 1.75 mm, and the inner wall diameter of the other two extrusion channel blocks is 2.85 mm, which enables the simultaneous extrusion of two different sizes of filaments in the same production cycle.

[0008] Preferably, the extrusion device further includes an air-assisted device, which is disposed in the die ring and connected to the flow channel, and has a certain slope with the flow channel to prevent collision.

[0009] Preferably, the flow channel between the flow divider cone and the die adopts a tapered structure, with the cross-section of the flow channel gradually decreasing in the direction close to the die. This structure can significantly increase the flow resistance of the material in the flow channel, thereby generating greater extrusion pressure during the extrusion process, which in turn promotes the orientation and crystallization of the material molecular chains and significantly improves the mechanical properties of the extruded material.

[0010] Preferably, the four detachable extrusion channel blocks inside the die are connected by a slot-and-clamp mechanism. A slot structure is provided on the die body, and corresponding clamping parts are provided at the corresponding positions of the extrusion channel blocks. Through the cooperation of the slots and clamping parts, the extrusion channel blocks can be quickly disassembled and installed. The thickness of the polytetrafluoroethylene coating is set to 35-40μm. This design not only facilitates rapid replacement after the extrusion channel blocks wear out, reducing equipment downtime, but also allows users to flexibly replace extrusion channel blocks of different sizes according to actual production needs, thereby adapting to diverse production requirements.

[0011] Preferably, the temperature of the constant temperature water tank in the annealing device is adjustable between 80°C and 100°C, and the annealing time is 30 min to 60 min. The annealing treatment adjusts the changes in the internal molecular structure of the filament, thereby improving the strength and toughness of the material. The distance between the two rollers in the tension regulating roller device is adjustable, providing a tensile stress to the filament during annealing and improving the extension and orientation of the molecular chains.

[0012] Compared with the prior art, this utility model provides a human implantable 3D printing filament preparation device, which has the following beneficial effects:

[0013] 1. The die of this device adopts a replaceable extrusion channel block, which can adapt to the production needs of products of different sizes and facilitates maintenance and cleaning. The detachable extrusion channel block can be directly removed from the die, which not only allows for thorough cleaning of its internal flow channels, reducing material accumulation, drooling and other problems, but also allows for timely inspection of die wear, replacement of worn parts, and reduction of maintenance costs. By regularly inspecting and maintaining the extrusion channel block of the die, the dimensional accuracy and surface quality of the filament can be ensured, and product defects can be reduced.

[0014] 2. The extrusion channel block of this device is coated with polytetrafluoroethylene (PTFE) with a thickness of 35-40 μm. This coating thickness provides better anti-sticking and wear resistance, effectively preventing PLA filaments from sticking to the die and ensuring smooth extrusion. Furthermore, for long-term continuous extrusion operations, this coating thickness offers better wear resistance, extending the die's service life.

[0015] 3. This device is equipped with an annealing unit, with an annealing time typically ranging from 30 to 60 minutes. By altering the annealing temperature and the stress on the filament, the crystallinity is changed. Extruded filaments, due to uneven cooling rates and molecular chain orientation, develop internal stress, leading to warping, deformation, and cracking. Annealing rearranges and relaxes the material's molecular chains, effectively eliminating internal stress and making the product more dimensionally stable. Simultaneously, annealing changes the crystallinity of the plastic, improving its physical properties and, to some extent, enhancing its heat and chemical resistance, allowing it to maintain stable performance under more complex environmental conditions. Attached Figure Description

[0016] To more clearly illustrate the technical solution of this utility model, the accompanying drawings used in the embodiments will be briefly introduced below.

[0017] Figure 1 This is a two-dimensional structural schematic diagram of the extrusion device described in this utility model.

[0018] Figure 2 This is a three-dimensional structural diagram of the flow divider cone in the extrusion device of this utility model.

[0019] Figure 3 This is a three-dimensional structural schematic diagram of the extrusion device described in this utility model.

[0020] Figure 4 This is a schematic diagram of the overall structure of the device of this utility model.

[0021] In the diagram: 1-Feeder, 2-Control device, 3-Conveying device, 31-Barrel, 32-Twin screw mechanism, 33-Temperature sensor, 4-Extrusion device, 41-Die body, 42-Screw, 43-Diverter cone, 44-Pin, 45-Die ring, 46-Die, 47-Diverter channel, 48-PTFE coating, 49-Die pressure ring, 410-Extrusion channel block, 411-Air-assisted device, 412-Flow channel hole, 5-Shaping and cooling device, 51-Cooling water tank, 52-Water circulation system, 53-Roller, 6-Traction device, 7-Annealing device, 71-Constant temperature water tank, 72-Tension regulating roller, 8-Cutting and winding device, 81-Cutter, 82-Roll. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Example 1

[0024] A device for preparing implantable 3D printed filament includes a feeder 1, a control device 2, a conveying device 3, an extrusion device 4, a shaping and cooling device 5, a traction device 6, an annealing device 7, and a cutting and winding device 8. The feeder 1 is connected to one end of the conveying device 3, which includes a barrel 31, a twin-screw mechanism 32, and a temperature sensor 33. The control device 2 is connected to both the feeder 1 and the conveying device 3. The temperature sensor 33 is installed at the end of the conveying device 3. The other end of the conveying device 3 is connected to one end of the extrusion device 4, which includes a die body 41, a flow divider cone 43, a die ring 45, and a die 46. The extrusion device 4 is connected to one end of the shaping and cooling device 5, which includes a cooling water tank 51, a water circulation system 52, and rollers 53. The other end of the shaping and cooling device 5 is equipped with a traction device 6, the core component of which is a synchronous pulley. The other end of the traction device 6 is connected to the annealing device 7, which includes a constant temperature water tank 71. The constant temperature water tank 71 is equipped with two sets of tension regulating roller devices 72 with adjustable spacing. The cutting and winding device 8 includes a cutter 81 and a roll 82. The temperature of the constant temperature water tank 71 of the annealing device 7 is adjustable between 80°C and 100°C.

[0025] One end of the die body 41 in the extrusion device 4 is provided with an external thread, and the other end of the conveying device 3 is provided with an internal thread. The extrusion device 4 and the conveying device 3 are securely connected by the threads. The flow divider cone 43 is located in the central area of ​​the die body 41 and is connected to the die body 41 by screws and pins. The flow divider cone 43 has eight flow channel holes 412 evenly distributed in a circle inside. The outer surfaces of both ends of the flow divider cone 43 and the inner surfaces of the die body 41 form a flow divider channel 47. The flow divider channel 47 is designed with a tapered structure. A die ring 45 is provided above the die body 41. The die ring 45 is fixedly connected to the die body 41 by screws and pins. The die 46 is provided with The die pressure ring 49 is fixedly connected to the die 46 by screws and pins. Four detachable extrusion channel blocks 410 are arranged side by side in the center of the die 46. A slot structure is provided on the die 46 body, and corresponding snap-fit ​​parts are provided at the corresponding parts of the detachable extrusion channel blocks 410. Through the cooperation of the slots and snap-fit ​​parts, the extrusion channel blocks can be quickly disassembled and installed. The detachable extrusion channel blocks 410 are uniformly coated with a polytetrafluoroethylene coating 48 with a thickness of 35μm. One extrusion channel block has an internal diameter of 1.75mm, and the other three extrusion channel blocks have an internal diameter of 2.85mm.

[0026] Example 2

[0027] A device for preparing implantable 3D printed filament includes a feeder 1, a control device 2, a conveying device 3, an extrusion device 4, a shaping and cooling device 5, a traction device 6, an annealing device 7, and a cutting and winding device 8. The feeder 1 is connected to one end of the conveying device 3, which includes a barrel 31, a twin-screw mechanism 32, and a temperature sensor 33. The control device 2 is connected to both the feeder 1 and the conveying device 3. The temperature sensor 33 is installed at the end of the conveying device 3. The other end of the conveying device 3 is connected to one end of the extrusion device 4, which includes a die body 41, a flow divider cone 43, a die ring 45, and a die 46. The extrusion device 4 is connected to one end of the shaping and cooling device 5, which includes a cooling water tank 51, a water circulation system 52, and rollers 53. The other end of the shaping and cooling device 5 is equipped with a traction device 6, the core component of which is a synchronous pulley. The other end of the traction device 6 is connected to the annealing device 7, which includes a constant temperature water tank 71. The constant temperature water tank 71 is equipped with two sets of tension regulating roller devices 72 with adjustable spacing. The cutting and winding device 8 includes a cutter 81 and a roll 82. The temperature of the constant temperature water tank 71 of the annealing device 7 is adjustable between 80°C and 100°C.

[0028] One end of the die body 41 in the extrusion device 4 is provided with an external thread, and the other end of the conveying device 3 is provided with an internal thread. The extrusion device 4 and the conveying device 3 are securely connected by the threads. The flow divider cone 43 is located in the central area of ​​the die body 41 and is connected to the die body 41 by screws and pins. The flow divider cone 43 has eight flow channel holes 412 evenly distributed in a circle inside. The outer surfaces of both ends of the flow divider cone 43 and the inner surface of the die body 41 form a flow divider channel. The flow divider channel is designed with a tapered structure, which can significantly increase the flow resistance of the material in the flow divider channel. A die ring 45 is provided above the die body 41. The die ring 45 is fixedly connected to the die body 41 by screws and pins. The die 46 is provided with a die pressure ring 49, which is fixedly connected to the die body 41 by screws and pins. The die ring 49 and the die 46 are fixedly connected by a nail. The gas-assisted device 411 is set in the die ring 45 and connected to the flow channel 47, and there is a certain slope between it and the flow channel 47. Four detachable extrusion channel blocks 410 are arranged side by side in the center of the die 46. A slot structure is set on the die 46 body, and corresponding snap-fit ​​parts are set on the corresponding parts of the detachable extrusion channel blocks 410. Through the cooperation of the slot and the snap-fit ​​parts, the extrusion channel blocks can be quickly disassembled and installed. The detachable extrusion channel blocks 410 are uniformly coated with a polytetrafluoroethylene coating 48 with a thickness of 40μm. The inner diameter of two of the extrusion channel blocks is 1.75mm, and the inner diameter of the other two extrusion channel blocks is 2.85mm.

[0029] Working Principle: When this utility model starts working, it is controlled by the control device 2. The feeder 1 feeds the uniformly mixed material into the conveying device 3. The continuous rotation of the twin-screw mechanism 32 pushes the material to the front end of the barrel 31. During the material flow, the temperature sensor 33 detects the temperature and feeds it back to the control device 2. At this time, due to the high temperature and the squeezing and shearing action of the twin screws, the material becomes a viscous melt. Then the melt flows into the extrusion device 4 and flows into the inlet die 46 through the flow channel holes 412 on the flow divider cone 43. At the same time, it is subjected to auxiliary pressurization by the gas-assisted device 411. The melt flows from the extrusion device 46 to the inlet die 46. The disassembled extrusion channel block 410 extrudes filaments of different shapes and sizes. The filaments pass through rollers 53 and enter the cooling water tank 51 for cooling and shaping. Under the traction of the traction device 6, the filaments are continuously fed forward. After the cooling process is completed, the filaments pass through the annealing device 7 and undergo annealing treatment inside the constant temperature water tank 71 to improve the mechanical properties of the material. Finally, the continuously moving filaments are wound up by the spool 82. When the predetermined length is reached, they are cut by the cutter 81, and the next production cycle is started. The entire process realizes efficient and continuous filament production, ensuring the quality and performance of the product.

[0030] When the filament enters the constant temperature water tank 71, the tension regulating roller device 72 provides tension to the filament, reducing the annealing time. Simultaneously, the constant temperature water tank 71 provides the necessary temperature for annealing. During extrusion, the shear force and rapid cooling of the filament cause highly oriented molecular chains, forming an anisotropic structure. This orientation results in high strength parallel to the extrusion direction, but low transverse strength, making it prone to cracking. During annealing, the filament is heated above its glass transition temperature, causing the molecular chains to rearrange and relax, reducing internal stress. Simultaneously, crystalline polymers can increase crystallinity during annealing, thereby enhancing the material's strength and heat resistance.

[0031] The filament material processed in this invention comprises 65% PLA, 20% PEG, 10% Fe3O4, and 5% BaSO4. PLA possesses advantages such as good shape memory, high strength, and high modulus, and exhibits good biocompatibility with the human body, making it suitable for use in tissue engineering scaffolds, sutures, and occlusion devices. PEG, with a molecular weight of 1500, serves as a functional filler to plasticize PLA and promote the biodegradability of the blend. Fe3O4 consists of magnetic nanoparticles that control the deformation of the component under an alternating magnetic field, forming micro-nano structures on the surface for magnetically driven shape memory state changes. BaSO4 primarily functions as an X-ray contrast agent, providing visibility under X-rays for postoperative tracking and diagnosis. The above description is merely a preferred embodiment of this invention, but the scope of protection of this invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in this invention, based on the technical solution and inventive concept of this invention, should be included within the scope of protection of this invention.

Claims

1. A human body implantable 3D printing filament preparation device, characterized by, The device comprises a feeder (1), a control device (2), a conveying device (3), an extrusion device (4), a shaping and cooling device (5), a traction device (6), an annealing device (7) and a cutting and winding device (8), the feeder (1) is connected with one end of the conveying device (3) below, the conveying device (3) comprises a cylinder (31), a double screw mechanism (32) and a temperature sensor (33), the control device (2) is connected with the feeder (1) and the conveying device (3), the temperature sensor (33) is installed at the end of the conveying device (3), the other end of the conveying device (3) is connected with one end of the extrusion device (4), the extrusion device (4) comprises a die body (41), a flow dividing cone (43), a die ring (45), a die (46) and a die ring (49), the other end of the extrusion device (4) is connected with one end of the shaping and cooling device (5), the shaping and cooling device (5) comprises a cooling water tank (51), a water circulation system (52) and a roller (53), the other end of the shaping and cooling device (5) is provided with the traction device (6), the core component of the traction device (6) is a synchronous pulley, the other end of the traction device (6) is connected with the annealing device (7), the annealing device (7) comprises a constant temperature water tank (71), two sets of tension control roller devices (72) with adjustable spacing are arranged inside the constant temperature water tank (71), the cutting and winding device (8) comprises a cutter (81) and a winding drum (82).

2. The human body implantable 3D printing wire preparation device according to claim 1, characterized in that, One end of the die body (41) in the extrusion device (4) is provided with external threads, the other end of the conveying device (3) is provided with internal threads, the extrusion device (4) and the conveying device (3) are stably connected through threads, the die ring (45) is arranged above the die body (41) and is fixedly connected with the die (46) and the die body (41) through screws and pins, the die ring (49) is arranged above the die (46) and is connected with the die (46) through screws and pins, the flow dividing cone (43) of the extrusion device (4) is located in the central region of the die body (41) and is connected with the die body (41) through screws and pins, the flow dividing channel (47) is formed between the outer surfaces of the two ends of the flow dividing cone (43) and the inner surfaces of the die body, eight flow channel holes (412) are arranged in the flow dividing cone (43) in a circumferentially uniform manner, four detachable extrusion passage blocks (410) are arranged in parallel in the central part of the die (46), and a polytetrafluoroethylene coating (48) is arranged on the inner wall of the extrusion passage block (410).

3. The human body implantable 3D printing wire preparation device according to claim 2, characterized in that, The extrusion device (4) further comprises a gas-assisted device (411), which is arranged in the die ring (45) and is communicated with the flow dividing channel (47) and has a certain slope with the flow dividing channel (47).

4. The apparatus for preparing a 3D printing filament for human implantation according to claim 3, wherein The flow dividing channel (47) between the flow dividing cone (43) and the die (46) is designed in a tapered structure, and the cross section of the flow dividing channel (47) gradually decreases in the direction close to the die.

5. The apparatus for preparing a 3D printing filament for human implantation according to claim 4, wherein Four detachable extrusion channel blocks (410) inside the die head (46) are connected in a clamping groove clamping manner, a clamping groove structure is arranged on the die head (46) body, and a corresponding clamping part is arranged at the corresponding part of the extrusion channel block (410), so that the quick disassembly and installation of the extrusion channel block (410) are realized through the cooperation of the clamping groove and the clamping part. The thickness of the polytetrafluoroethylene coating (48) is set to 35-40 μm.

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