A biological 3D printing system and method

Abstract

The present invention relates to a 3D printing system and method. The system includes: a first unit for storing ink with solid particles; a third unit for ejecting the ink to print a 3D structure. The 3D printing system is configured with a second unit disposed horizontally for preprocessing the ink. The second storage portion of the second unit can receive the ink flowing out of the first unit and store the ink until it is output to the third unit when there is a printing requirement. Among them, during the period when the second storage portion stores the ink in the second unit, the ink can be lifted upward at a speed greater than or equal to the precipitation speed of at least part of the solid particles in the ink by rotating along the axis, so as to perform preprocessing on the ink. The method includes: moving the movable member away from the opening to introduce the ink into the second storage portion; rotating the second storage portion around the axis to drive the ink to rotate; moving the movable member towards the opening to discharge the ink from the second storage portion.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a biological 3D printing system and method. Background Art

[0002] Biological 3D printing refers to the use of the principles and methods of 3D printing to print biological materials (including natural biological materials, synthetic biological materials or cell solutions) into designed three-dimensional structures. Different from ordinary 3D printing technologies, the biological tissues or organs produced by biological 3D printing technology also have certain biological functions and need to provide conditions for the further growth of cells and tissues. Due to the above characteristics, biological 3D printing technology faces many specific technical problems in its development.

[0003] CN104552956A discloses a clean and easy-to-use biological material printing nozzle. The printing nozzle includes a nozzle housing, a biological material extrusion driving module, a contact temperature control module, and a biological material quick replacement module; the biological material extrusion driving module includes a high-precision servo electric cylinder, an electric cylinder push rod, an annular magnet limiter, and a syringe push rod head from top to bottom, and is coaxially arranged; the contact temperature control module includes a semiconductor refrigeration sheet, an external fluid cooling circulation system, and a fixed gland. The hot end face of the semiconductor refrigeration sheet is attached to the liquid cooling head, and the cold end face is attached to the inner wall of the fixed gland; the biological material replacement module includes a syringe, a cold guide sleeve, and a heat preservation sleeve; magnets with different polarities are arranged in the magnet mounting holes of the fixed gland and the cold guide sleeve.

[0004] CN105670918A discloses a biological printer nozzle assembly and a biological printer. Among them, the biological printer nozzle assembly includes a nozzle and an extension rod spaced apart from the nozzle and adjacent to the nozzle outlet. The extension rod is provided with a slender flow channel for the fluid printing unit of the biological printing material to be ejected directionally through the flow channel. By arranging an extension rod with a slender flow channel adjacent to the nozzle outlet, the biological printer nozzle assembly is used for the fluid printing unit of the biological printing material to be ejected directionally through the flow channel. The slender flow channel can perform directional sorting on the fluid printing unit and reduce the possibility of blockage.

[0005] However, the nozzle mechanisms of the prior art are usually vertically placed, with a relatively long height direction, obvious particle precipitation phenomenon, and the structure printed first is the area with the most serious particle precipitation, resulting in an uneven phenomenon where the structure printed first has more particles and the structure printed later has fewer particles. Moreover, it is easy to cause nozzle blockage, especially when the ink selected is low-viscosity ink mixed with solid particles, the non-uniformity of the printed structure will be amplified, making it difficult to be applicable to the 3D printing process with high printing accuracy requirements.

[0006] In addition, on the one hand, there are differences in the understanding of those skilled in the art; on the other hand, when the applicant made this invention, a large number of documents and patents were studied, but due to space limitations, all details and content were not listed in detail. However, this by no means means that this invention does not possess the features of these prior arts. On the contrary, this invention already possesses all the features of the prior arts, and the applicant reserves the right to add relevant prior arts in the background art. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present invention provides a biological 3D printing system and method to solve at least some of the above technical problems.

[0008] The present invention discloses a biological 3D printing system, which includes: a first unit for storing ink with solid particles; a third unit for ejecting the ink to print a 3D structure. Preferably, the first unit can generally serve as a feeding mechanism of the biological 3D printing system, the second unit can generally serve as a nozzle mechanism of the 3D printing system, and the third unit can generally serve as a nozzle mechanism of the biological 3D printing system.

[0009] Preferably, the biological 3D printing system is configured with a second unit arranged horizontally for preprocessing the ink. The second storage part of the second unit can receive the ink flowing out of the first unit and store the ink until it is output to the third unit when there is a printing requirement. Among them, the second storage part can at least make the upward lifting speed of the ink greater than or equal to the precipitation speed of at least part of the solid particles in the ink by rotating along the axis during the ink storage period of the second unit to perform preprocessing on the ink.

[0010] The nozzle mechanisms of conventional biological 3D printing systems (i.e., the second unit of the present invention) are all vertically placed, with a relatively long height direction, obvious particle precipitation phenomenon, and the structure printed first is the area with the most serious particle precipitation, resulting in an uneven phenomenon where the structure printed first has more particles and the structure printed later has fewer particles. Different from this, the second unit of the present invention is horizontally placed, that is, the distance in the height direction is reduced, the total number of precipitated particles per unit area at the bottom is reduced, and the printed structure sequence is horizontally unfolded, that is, the ink near the opening side exits first, and the deposition direction is the height direction, and there will be no obvious difference in the total number of particles between the first printed structure and the last printed structure.

[0011] According to a preferred embodiment, the second storage part can rotate around the axis driven by a third motor, wherein the third motor is controlled by a control signal generated by a control unit to drive the second storage part to perform one-way continuous rotation or two-way swinging rotation.

[0012] The present invention achieves the anti-settling function of the low-viscosity ink mixed with solid particles by rotating the horizontally placed second storage part around the axis and driving the ink mixed with solid particles in the second storage part to rotate synchronously.

[0013] According to a preferred embodiment, an active part driven by a second motor to move along the axis of the second storage part is arranged in the second storage part. The active part can move in a direction away from the opening to introduce ink into the second storage part with a tendency to increase the storage space, and the active part can move in a direction close to the opening to discharge ink from the second storage part with a tendency to decrease the storage space.

[0014] The present invention adopts a stirring method without a stirring paddle, which enables the ink to be output by means of a motor pushing an active part (such as a piston), rather than an air-jet method with a stirring paddle. This is because the air-jet method is a constant-pressure jet, not a constant-flow jet, and the jet flow rate is related to the gas pressure, the internal structure of the pipeline, and the ink viscosity. When printing materials with slightly changing viscosities during the printing process, it is easy to cause uneven flow rates and produce unqualified printing structures. At the same time, it is generally difficult to control the printing of low-viscosity materials by air-jet printing, and the cost of an air valve with a control accuracy of about 0.1 kPa is much higher than that of a motor structure with the same control accuracy. Therefore, the horizontally placed rotatable second storage part of the present invention can output ink by means of a motor pushing an active part, obtaining better printing stability and control accuracy at low cost.

[0015] According to a preferred embodiment, the second unit is connected to the first unit and the third unit through different communication parts respectively, and independent on-off parts connected to the control unit are correspondingly arranged on each communication part. All the on-off parts in response to the control signals of the control unit can be arranged in such a way that they are not in a connected state at the same time.

[0016] Generally, the printing accuracy of the ink output by the method of a motor pushing a piston is negatively correlated with the diameter of the second storage part. Therefore, generally, in order to improve the printing accuracy, the diameter of the second storage part should not be too large. However, a second storage part with a small diameter will bring the defect of frequent manual feeding during the continuous production process, which affects the printing efficiency. The present invention automatically controls each on-off part and each motor through the control unit, so that the second storage part can automatically replenish materials from the closed first storage part with a relatively larger storage space as needed, realizing high-efficiency printing. And the feeding process, storage process, and / or discharging process of the second unit can be adjusted through the control signals generated by the control unit, so that the biological 3D printing system of the present invention can further improve the printing accuracy and the internal material distribution of the printed structure is more uniform.

[0017] According to a preferred embodiment, a collection unit for acquiring data information related to solid particles in the ink can be disposed on a first communication part connecting the first unit and the second unit, wherein the data information related to the solid particles at least includes the particle number and / or the particle size.

[0018] The collection unit of the present invention can utilize an optical particle counting method to acquire data information related to solid particles mixed in the ink flowing through the first communication part, wherein the data information related to the solid particles at least can include the particle number and / or the particle size.

[0019] According to a preferred embodiment, the control unit can at least adjust the output power of the second motor based on the data information related to the solid particles acquired by the collection unit and / or the physical and chemical properties of the ink.

[0020] Based on the data information acquired by the collection unit, the control unit of the present invention can determine the number and / or the particle size of the solid particles entering the second storage part at any time series. In combination with the physical and chemical properties of the ink, it can simulate the residence positions of different solid particles in the cavity of the second storage part after entering with the ink in each time series batch, so as to judge the real-time distribution state of the solid particles in the second storage part, and timely generate at least control signals for regulating the operating state of the second unit to achieve a substantially uniform distribution of the solid particles in the second storage part considering factors such as the number and / or the particle size.

[0021] According to a preferred embodiment, the first unit is configured with a first storage part for containing ink, and a stirring blade driven by a first motor to rotate can be disposed in the first storage part.

[0022] Such a setting can enable the ink contained in the first storage part to be in a stirred motion state, so as to play a function of preventing precipitation of the low-viscosity ink mixed with solid particles.

[0023] According to a preferred embodiment, the first storage part is provided with a gas valve restricted to open unidirectionally, wherein the opening degree of the gas valve can be adjusted at least based on the change of the stirring mode of the stirring blade.

[0024] Since the ink is generally a non-Newtonian compressible fluid, and the material pipe, the material cylinder, etc. may have a certain pressure deformation, during the printing process, the ink accumulating a certain pressure will continue to spray out through the nozzle to release the pressure after the printing stops. This phenomenon of the continuous outflow of the ink is generally called the salivation phenomenon. To avoid the salivation phenomenon affecting the surface quality of the printed structure, the biological 3D printing system of the present invention can utilize the first on-off part to close and lock the pressure in the first storage part, so as to greatly reduce the salivation phenomenon and improve the forming quality.

[0025] According to a preferred embodiment, the third unit is configured with nozzles arranged in the vertical direction, and the ink ejected by the nozzles onto the forming platform is at least temperature-adjusted by a temperature control component, wherein the moving component configured in the third unit can adjust the relative positional relationship between the nozzles and the forming platform.

[0026] With such an arrangement, the ink about to be ejected can be heated or cooled by the temperature control component according to the requirements of ink printing, so that the ink ejected onto the forming platform through the nozzles can meet the temperature required for the printed structure.

[0027] The present invention also discloses a biological 3D printing method, which includes the following steps:

[0028] During the feeding process of the second unit, the movable member moves away from the opening in a direction to increase the storage space to introduce the ink into the second storage part;

[0029] During the ink storage process of the second unit, the second storage part rotates around the axis to drive the ink in the second storage part to rotate, and the second storage part can rotate in such a way that the upward lifting speed of the ink is greater than or equal to the precipitation speed of at least part of the solid particles in the ink;

[0030] During the discharging process of the second unit, the movable member moves towards the opening in a direction to decrease the storage space to discharge the ink from the second storage part.

[0031] Preferably, at least the feeding process, the ink storage process, and / or the discharging process of the second unit can be adjusted by the control signal generated by the control unit. Description of the Drawings

[0032] Figure 1 is a simplified overall structural schematic diagram of the biological 3D printing system of the present invention;

[0033] Figure 2 is a simplified schematic diagram of the module connection relationship of a preferred embodiment of the biological 3D printing system provided by the present invention.

[0034] List of Reference Numerals

[0035] 1: Nozzle; 2: Temperature control component; 3: Second communication part; 4: Second on-off part; 5: Second storage part; 6: Movable member; 7: Second motor; 8: Third motor; 9: Transition part; 10: First storage part; 11: Air valve; 12: Stirring blade; 13: First motor; 14: First communication part; 15: First on-off part; 16: Forming platform; 100: First unit; 200: Second unit; 300: Third unit; 400: Control unit; 500: Acquisition unit. Detailed Embodiments

[0036] The following will be described in detail with reference to the accompanying drawings.

[0037] Figure 1 It is a simplified overall structural schematic diagram of the biological 3D printing system of the present invention; Figure 2 It is a simplified schematic diagram of the module connection relationship of a preferred embodiment of the biological 3D printing system provided by the present invention.

[0038] Example 1

[0039] The present invention discloses a biological 3D printing system, especially a 3D printing system suitable for inks with low viscosity mixed with solid particles, which at least includes a first unit 100 for storing ink, a second unit 200 for preprocessing the ink, and a third unit 300 for inkjet printing. Among them, the second unit 200 for preprocessing the ink can at least play a partial anti-sedimentation function. Preferably, the ink can be preferentially stored in the first unit 100. When a printing operation needs to be performed, the ink in the first unit 100 can be first introduced into the second unit 200, and the ink temporarily stored in the second unit 200 can be introduced into the third unit 300 according to the actual printing requirements, and finally the ink is ejected through the third unit 300. Preferably, the biological 3D printing system may further include a control unit 400 communicatively connected to the first unit 100, the second unit 200, and / or the third unit 300, wherein the control unit 400 can generate control signals for regulating the first unit 100, the second unit 200, and / or the third unit 300 based on one or more parameters obtained by the acquisition unit 500.

[0040] Preferably, the ink can be stored in the inner cavity of the first storage part 10 of the first unit 100, and a maximum liquid level line and a minimum liquid level line are provided in the inner cavity of the first storage part 10. Any storage state of the ink in the first storage part 10 should be maintained within the space defined by the maximum liquid level line and the minimum liquid level line. Among them, the ink in the first storage part 10 at least includes a static storage state and a dynamic storage state. Preferably, the ink can usually be stored in the first storage part 10 in a dynamic storage state to avoid the precipitation of solid particles in the ink. Among them, at least when the ink stored in the first storage part 10 is lower than the minimum liquid level line, new ink can be replenished into the first storage part 10, and the ink in the first storage part 10 can be in a static storage state when replenishing the ink. Preferably, the volume of the first storage part 10 can be further preferably 500 ml - 5 L.

[0041] Preferably, the ink in the first storage unit 10 can at least be switched to a dynamic storage state driven by the stirring blade 12, and the stirring blade 12 can be at least submerged by the ink. The stirring blade 12 can be any shape that can play a stirring role, so that the stirring blade 12 rotates around the rotating shaft under the driving action of the first motor 13, thereby realizing the anti-sediment function of the first unit 100 for the low-viscosity ink mixed with solid particles.

[0042] Preferably, the first storage unit 10 is provided with an air valve 11 that allows one-way flow from the outside to the inside of the first storage unit 10, so that only gas is allowed to enter the inside from the outside of the first storage unit 10, and gas is not allowed to be discharged from the inside of the first storage unit 10. Such a setting can reduce or even avoid the volatilization of the ink and play a role in replenishing the air pressure in the first storage unit 10 in a timely manner. Further, the air valve 11 can be arranged above the highest liquid level line of the ink in the first storage unit 10, and preferably arranged at the top of the first storage unit 10.

[0043] Preferably, due to the stirring action of the stirring blade 12 and the pressure control action of the air valve 11, the volatilization phenomenon of the ink can be promoted or inhibited. The control unit 400 can at least adjust the operating parameters of the stirring blade 12 and / or the air valve 11 based on parameters such as the current ink stock, ink temperature, and top air pressure in the first storage unit 10. Among them, the adjustment of the stirring method of the stirring blade 12 can at least include the stirring speed and / or the stirring direction, and the adjustment of the operating parameters of the air valve 11 can at least include the opening timing of the air valve 11 and / or the air pump parameters connected to the air valve 11.

[0044] Preferably, the ink in the first storage unit 10 can enter the second storage unit 5 configured in the second unit 200 through the first communication part 14. The second storage unit 5 is configured with a cavity with an adjustable space size for temporarily storing the ink, and the ink temporarily stored in the second storage unit 5 can then enter the nozzle 1 configured in the third unit 300 through the second communication part 3.

[0045] Preferably, the first connecting part 14 and the second connecting part 3 can be configured as tubular structures, and the materials thereof can both be selected as materials that do not react with the ink. Among them, it can be further preferably a rigid tube to reduce the pressure accumulation on the tube wall. Preferably, corresponding on-off parts can be configured on both the first connecting part 14 and the second connecting part 3. The on-off part can at least be used to adjust the opening degree of the tubular connecting part to achieve the regulation of the ink flow rate. Among them, the on-off part can be one or a combination of two of an electromagnetic valve, a piezoelectric valve, and a motor valve, and can be further preferably a small inner diameter tube valve. Further, the first on-off part 15 configured on the first connecting part 14 and the second on-off part 4 configured on the second connecting part 3 can be respectively communicatively connected to the control unit 400 to receive the control signal for switching the on-off state issued by the control unit 400. Among them, the control unit 400 can at least issue control signals for "switching the connecting state" to the first on-off part 15 and the second on-off part 4 non-simultaneously, that is, the first on-off part 15 and the second on-off part 4 are not simultaneously in a connected state, or at least one on-off part is in a blocked state.

[0046] Preferably, when the third motor 8 configured in the horizontally placed second unit 200 starts, it can drive the transition part 9 to rotate. The transition part 9 is connected to one end of the second storage part 5 through at least part of its structure to drive the second storage part 5 to rotate synchronously. Preferably, the rotation mode of the third motor 8 can be regulated by the control unit 400. For example, it can be a single-direction continuous rotation in the counterclockwise or clockwise direction, or a combined swinging rotation in the clockwise and counterclockwise directions at a certain rotation angle. It is further preferably a swinging rotation in a single direction not exceeding 360 degrees. Among them, the rotation of the third motor 8 at least ensures that the upward lifting speed of the ink is greater than or equal to the precipitation speed of the particles in the ink.

[0047] Preferably, the ink can flow into and / or out of the second storage part 5 through the opening configured at one end of the second storage part 5 (in the horizontal direction). Preferably, the movable part 6 configured in the second storage part 5 defines the storage space of the ink in the second storage part 5. The movable part 6 can be configured as a piston or a structure having the same shape as the piston to achieve a sealed partition with an adjustable space size. Among them, by adjusting the position of the movable part 6 in the second storage part 5, the size of the storage space is adjusted. The movable part 6 moves away from the opening to increase the storage space, and the movable part 6 moves closer to the opening to reduce the storage space. Further, the movement of the movable part 6 in the inner cavity of the second storage part 5 can provide power for the inflow and / or outflow of the ink. Preferably, the volume of the second storage part 5 can be 0 - 50 ml, and further preferably 0 - 10 ml.

[0048] Preferably, the third unit 300 arranged in the vertical direction may at least include a printing nozzle 1 and a forming platform 16. Among them, the forming platform 16 arranged below the printing nozzle 1 in the vertical direction can receive the ink ejected from the printing nozzle 1. Preferably, the inner diameter of the printing nozzle 1 may be 0.01-3 mm, and more preferably 0.05-0.8 mm.

[0049] Preferably, the third unit 300 can be configured with a motion component for adjusting the three-dimensional spatial position relationship between the nozzle 1 and the forming platform 16, so as to realize the three-dimensional spatial movement of the nozzle 1 and / or the forming platform 16 through the motion component. Among them, the motion mode of the motion component can be regulated by the control unit 400 to achieve precise positioning of the ejected ink based on the relative movement between the nozzle 1 and the forming platform 16. Further, a temperature control component 2 can be configured in a partial area (especially near the nozzle 1) between the second on-off part 4 on the second communication part 3 and the nozzle 1, at least for adjusting the temperature of the ink entering the nozzle 1 according to the ink printing requirement. The adjustment method may include heating and / or refrigeration, and the controlled temperature is more preferably 0-70 °C.

[0050] According to a preferred embodiment, the present invention prevents the precipitation of solid particles in the ink during the printing process by arranging a stirring blade 12 driven by a first motor 13 in the first unit 100 and an active body driven by a second motor 7 to displace and a second storage part 5 driven by a third motor 8 to rotate in the second unit 200 arranged in the horizontal direction, thereby avoiding uneven distribution of the internal materials of the printed structure and easily causing the situation of nozzle 1 blockage. Further, although the above configuration method can prevent the precipitation of solid particles through various configuration methods, thereby achieving the effect of uniform distribution of the internal materials of the printed structure, for the printing process with high printing accuracy, it is necessary to adjust the operating parameters of the second unit 200 by the control unit 400 to change the flow mode of the ink flowing into and / or out of the second storage part 5, thereby improving the uniformity of the material distribution by enhancing the dispersion of solid particles during the printing process. Preferably, the dispersion refers to the degree of uniform distribution of the internal materials of the printed structure, and can be characterized by the dispersion degree of the number and / or particle size of the solid particles ejected from the nozzle 1 with the ink in the time series.

[0051] Such a setting is because the second communication part 3 is preferably a thin tube with a hollow interior. The ink mixed with solid particles flowing in the second communication part 3 can generally only flow in sequence according to the sequence of entering the second communication part 3. It is difficult to adjust the distribution of solid particles in the second communication part 3 where disordered flow is not likely to occur. Therefore, it is only possible to optimize the distribution state of solid particles in the second storage part 5 to control the sequence of the ink mixed with solid particles entering the second communication part 3.

[0052] Preferably, optimizing the distribution state of solid particles in the second storage part 5 requires at least regulating the feeding process of the second unit 200. However, since ink usually needs to be stored away from light, it is difficult for the acquisition unit 500 to directly monitor the distribution state of solid particles in the second storage part 5 in real time. Therefore, the control unit 400 of the present application can simulate the distribution state of solid particles in the second storage part 5 based on the data information related to the solid particles mixed in the ink obtained by the acquisition unit 500 provided on the first communication part 14, and adjust the distribution state of solid particles in the second storage part 5 by generating a control signal, so as to ensure the relatively uniform distribution of solid particles in the ink entering the second communication part 3 and the nozzle 1, and to achieve a uniform distribution of the internal material of the printed structure.

[0053] Preferably, the acquisition unit 500 provided on the first communication part 14 can use the optical particle counting method to obtain the data information related to the solid particles mixed in the ink flowing through the first communication part 14. Among them, the data information related to the solid particles can at least include the particle number and / or the particle size. Further, the acquisition unit 500 using the optical particle counting method can be based on the physical techniques of extinction (LE) or light scattering (LS), or a combination of the two physical techniques to achieve the acquisition of data information. Exemplarily, the acquisition unit 500 can select a sensor implementing single-particle optical sensing or an improved device for such a sensor, and among them, the selected device can be applicable to the ink.

[0054] Preferably, based on the data information obtained by the acquisition unit 500, the control unit 400 can determine the number and / or particle size of solid particles entering the second storage part 5 at any time series. In combination with the physical and chemical properties of the ink, it can simulate the residence positions of different solid particles entering the cavity of the second storage part 5 with the ink in each time series batch, so as to judge the real-time distribution state of solid particles in the second storage part 5, and timely generate at least a control signal for regulating the operating state of the second unit 200 to achieve a substantially uniform distribution of solid particles in the second storage part 5 considering the factors of quantity and / or particle size.

[0055] Preferably, when the control unit 400 controls the residence position of the simulated solid particles after entering the cavity of the second storage part 5 with the ink, the residence position is the final position of the solid particles predicted by the control unit 400 in the stationary second storage part 5. It is not the landing position of the solid particles, but also takes into account the further displacement of the solid particles that have landed at the bottom of the second storage part 5 due to the subsequent pulling process of the moving part 6. In this regard, the control unit 400 can calculate the corresponding compensation distance to calculate the final position in combination with the landing position. Preferably, the control unit 400 can at least predict the landing position of the solid particles at each time series based on the particle size of the solid particles, the average pulling speed of the moving part 6, and the position of the opening on the second storage part 5, and at least calculate the compensation distance based on the particle size and the remaining pulling distance of the moving part 6. The degree of influence of solid particles with different particle sizes can be obtained through experiments to obtain the influence coefficient, which is used to calibrate the compensation distance.

[0056] Preferably, for the case where the particle size of the solid particles entering the second storage part 5 is relatively uniform, that is, when the particle size of the solid particles captured by the acquisition unit 500 in a plurality of initial consecutive time series is within or mostly within the preset particle size range, the control unit 400 can drive the second motor 7 to drive the moving part 6 to move away from the opening in the second storage part 5 at a substantially uniform pulling speed. Further, the control unit 400 can compare in real time the relationship between the number of solid particles in the same particle size range in any plurality of consecutive adjacent time series and the preset number threshold, and adjust the output power of the second motor 7 based on the comparison result in combination with the physical and chemical properties of the ink, thereby accelerating or slowing down the pulling speed of the moving part 6. The number threshold can at least include a maximum number threshold and a minimum number threshold. The situation exceeding the maximum number threshold indicates that the solid particles with substantially the same particle size will enter the second storage part 5 in a relatively aggregated manner, and the situation exceeding the minimum number threshold indicates that the solid particles with substantially the same particle size will enter the second storage part 5 in a relatively loose manner. Both the relatively aggregated manner and the relatively loose manner will affect the uniform distribution state of the solid particles in the second storage part 5. Preferably, the control unit 400 can only compare the particle number with the preset number threshold for the solid particles with particle sizes within the preset particle size range to reduce the operation load, where the preset particle size range is at least determined based on the properties of the (produced or purchased) ink to cover relatively more solid particles by selecting a relatively moderate particle size value.

[0057] Preferably, in the case where the particle size of the solid particles entering the second storage unit 5 is relatively non-uniform, that is, when the particle size of the solid particles captured by the acquisition unit 500 in a plurality of initial consecutive time series at least partially exceeds the preset particle size range, the control unit 400 can drive the second motor 7 to drive the movable member 6 to move in the second storage unit 5 in a direction away from the opening at a substantially non-uniform pulling speed. Further, the pulling speed of the movable member 6 can at least change in a trend of first decreasing, then increasing, and then decreasing after the second motor 7 provides an initial acceleration. Among them, since the different particle sizes of the solid particles and the time series of their entry will affect their landing positions and final positions in the second storage unit 5, by setting at least two speed turning points, the pulling process of the movable member 6 is divided into at least three sub-processes with different speed change trends. With the physical block of the movable member 6, the aggregation of relatively small particle-sized solid particles at the end far from the opening can be restricted through decelerated motion, and the aggregation of relatively large particle-sized solid particles near the opening can be restricted through accelerated motion. Further, the change range of the pulling speed can also be fine-tuned based on the relationship between the number of solid particles in a certain particle size range and the preset number threshold, and the fine-tuning method can be the same as or similar to the above preferred embodiment.

[0058] Preferably, after the second unit 200 completes the feeding process, it can switch to the storage process. During the storage process, the control unit 400 can drive the third motor 8 to drive the second storage unit 5 to rotate around the axis with the transition part 9. Among them, the control unit 400 can determine the rotation mode of the third motor 8 based on the distribution state of the solid particles in the second storage unit 5 obtained by simulation. The rotation mode can be, for example, a single-direction continuous rotation in the counterclockwise or clockwise direction, or a combined swinging rotation in the clockwise and counterclockwise directions at a certain rotation angle. Further preferably, it is a single-direction swinging rotation not exceeding 360 degrees.

[0059] Preferably, the rotation of the third motor 8 driven by the control unit 400 can at least ensure that the upward lifting speed of the ink is greater than or equal to the precipitation speed of the particles in the ink. Among them, the control unit 400 can calculate the precipitation speed of the largest particle-sized solid particles in the ink based on the number and particle size of the solid particles entering the second storage unit 5 obtained by the acquisition unit 500 to set the rotation mode of the third motor 8.

[0060] Preferably, the control unit 400 can adjust the pushing speed output by the second motor 7 to the movable member 6 based on the printing requirement and adjust the rotation speed of the third motor 8 driving the second storage unit 5 to match the pushing speed of the movable member 6, so as to ensure that the upward lifting speed of the ink is greater than or equal to the precipitation speed of the particles in the ink during the discharging process of the second unit 200.

[0061] Furthermore, based on the regulation of the feeding process of the second unit 200 by the control unit 400, the distribution state of the solid particles in the second storage part 5 is optimized. The control unit 400 then effectively regulates the discharging process of the second unit 200 by changing the operating modes of the second motor 7 and / or the third motor 8 to control the sequence of the ink entering the second communication part 3.

[0062] Preferably, the control unit 400 can assign corresponding sequences to the ink mixed with solid particles that is about to enter the second communication part 3. This sequence is usually assigned to a unit volume of ink so that the storage space of the second storage part 5 can be occupied by several unit volumes of ink, or it can be said that the storage space of the second storage part 5 contains several ink sets. Moreover, the ink set closer to the opening can be assigned a more forward sequence, such that when the second motor 7 drives the movable part 6 to move towards the direction close to the opening, the ink set with a more forward sequence can enter the second communication part 3 relatively earlier and flow in an orderly manner. This orderly flow means that the ink sets can flow in the second communication part 3 generally according to the assigned sequence, and it is difficult to have disordered flows such as overtaking, stagnation, and mixing. Preferably, for a unit volume of ink (or ink set), the unit volume can be determined by the control unit 400 based at least on the physical and chemical properties of the ink and the solid particles and the structural parameters of the second storage part 5. And at any determined unit volume, the control unit 400 can define the space occupied by the ink sets of each sequence, and its spatial structure can be the same or different. Among them, different spatial structures are usually specially set by the control unit 400 based on the structural parameters of the second storage part 5 and the fluid characteristics, especially for the area near the opening of the second storage part 5.

[0063] Further, since the fluid has a completely different flow pattern at the narrow opening than in the open cavity, the control unit 400 can preferably perform a spatial construction of a special structure on the ink aggregate in the area near the opening of the second storage part 5 based on the flow pattern of the ink at the narrow opening. It can generally make the multiple ink aggregates in the area near the opening of the second storage part 5 show an expanding coating morphology in sequence as the sequence increases. The expanding coating morphology can be manifested as the space occupied by the ink aggregate with a relatively later sequence in the ink aggregates of two adjacent sequences can generally cover the space occupied by the ink aggregate with a relatively earlier sequence, thereby forming a coating morphology. In other words, make a cross-section orthogonal to the rotation axis in the area near the opening of the second storage part 5, and the slice of this cross-section passes through the spaces occupied by at least two different sequences of ink aggregates. Based on this, the control unit 400 can at least achieve the exchange of some solid particles between the two spaces occupied by the ink aggregates of adjacent sequences during the discharging process by adjusting the third motor 8. Among them, the adjustment of the third motor 8 by the control unit 400 is at least carried out according to the scheme determined after simulating the discharging process of the second unit 200 based on the predicted solid particle distribution state of the second storage part 5.

[0064] Preferably, through the precise regulation of the control unit 400, the solid particles can enter the nozzle 1 with the ink in the given sequence in such a way that the number of particles and / or the particle size are approximately evenly distributed in the ink aggregates of each sequence and are ejected towards the forming platform 16, and the internal material distribution of the printed structure is made uniform under the coordinated drive of the moving components.

[0065] Embodiment 2

[0066] This embodiment is a further improvement of Embodiment 1, and the repeated content will not be elaborated.

[0067] The present invention also discloses a biological 3D printing method, which may include the following steps:

[0068] S1. Add the low-viscosity ink mixed with solid particles into the first storage part 10, and turn on the first motor 13 to drive the stirring blade 12 to stir the low-viscosity ink mixed with solid particles to prevent particle precipitation;

[0069] S2. During the feeding process of the second unit 200, turn on the first on-off part 15, turn off the second on-off part 4, and pull the movable part 6 by starting the second motor 7 to move in a direction away from the opening (shown as moving to the left in the figure) with a tendency to increase the storage space. Based on the movement of the movable part 6, the low-viscosity ink mixed with solid particles can be sucked from the first storage part 10 into the second storage part 5 through the second communication part 3, and turn off the first on-off part 15 when the feeding requirement is reached;

[0070] S3. During the material storage process of the second unit 200, turn on the third motor 8, drive the second storage part 5 to rotate around the axis through the transition part 9, so as to drive the ink with low viscosity and mixed with solid particles in the second storage part 5 to rotate, playing a role in preventing precipitation of the ink with low viscosity and mixed with solid particles;

[0071] S4. During the material discharging process of the second unit 200, turn on the second on-off part 4, and make the second motor 7 push the movable part 6 to move in the direction close to the opening (shown as moving to the right in the figure) with the tendency of reducing the storage space, so that the ink passes through the first communication part 14 to reach the nozzle 1 and is sprayed to the designated position on the forming platform 16 through the nozzle 1. After the printing work of the current round is completed, turn off the second motor 7 and the second on-off part 4. Among them, the completion of the printing work of the current round can be that the ink in the second storage part 5 is used up by printing or the printing task ends;

[0072] S5. If the ink in the second storage part 5 is used up by printing, return to the above step S2. After replenishing the ink to the second storage part 55, repeat the above steps S3 and S4 until the printing task ends.

[0073] Preferably, the control unit 400 can at least generate corresponding control signals during the feeding process, material storage process and / or discharging process of the second unit 200 to realize the uniform distribution of solid particles.

[0074] Exemplarily, the biological 3D printing method of the present invention can complete the following steps:

[0075] S1. Add 500 ml of 10% PLGA ink with low viscosity and mixed with magnesium powder particles (diameter 30 microns) to the first storage part 10 with a volume of 500 ml. Turn on the first motor 13 to drive the stirring blade 12 to stir the ink with low viscosity and mixed with solid particles at a speed of 30 revolutions per minute to prevent particle precipitation;

[0076] S2. During the feeding process of the second unit 200, turn on the first on-off part 15, turn off the second on-off part 4, and pull the movable part 6 at the speed indicated by the control unit 400 (for example, 10 mm / s) by starting the second motor 7 to move in the direction away from the opening (shown as moving to the left in the figure) with the tendency of increasing the storage space of 10 ml. Based on the movement of the movable part 6, the ink with low viscosity and mixed with solid particles can be sucked from the first storage part 10 to the second storage part 5 through the second communication part 3. When the feeding requirement is reached, turn off the first on-off part 15;

[0077] S3. During the material storage process of the second unit 200, turn on the third motor 8, drive the second storage part 5 through the transition part 9 to rotate around the axis in the rotation mode indicated by the control unit 400 (reciprocating swing rotation with ±180° and a swing speed of 30° / s), so as to drive the ink with low viscosity and mixed with solid particles in the second storage part 5 to rotate, and perform the anti-sediment function of the ink with low viscosity and mixed with solid particles;

[0078] S4. During the material discharging process of the second unit 200, turn on the second on-off part 4, and make the second motor 7 push the moving part 6 in the direction close to the opening (moving rightward as shown in the figure) at the speed indicated by the control unit 400 (for example, 6 μm / s) with the tendency of reducing the storage space, so that the ink reaches the nozzle 1 through the first communication part 14 (inner diameter 3 mm). The temperature control component 2 can be used to keep the ink temperature at 25°C. The ink can be sprayed from the outlet of the nozzle 1 (inner diameter 0.5 mm) onto the forming platform 16 placed in the forming space at -30°C. The moving speed of the moving component is 20 mm / s. After the printing work of the current round is completed, turn off the second motor 7 and the second on-off part 4;

[0079] S5. If the ink in the second storage part 5 is used up during printing, return to the above step S2. After replenishing the ink in the second storage part 55, repeat the above steps S3 and S4 until the printing task ends.

[0080] It should be noted that the above specific embodiments are exemplary. Those skilled in the art can come up with various solutions inspired by the disclosure content of the present invention, and these solutions also belong to the disclosure scope of the present invention and fall within the protection scope of the present invention. Those skilled in the art should understand that the description and drawings of the present invention are illustrative and do not constitute a limitation to the claims. The protection scope of the present invention is defined by the claims and their equivalents. The description of the present invention contains multiple inventive concepts. Phrases such as "preferably", "according to a preferred embodiment", or "optionally" all indicate that the corresponding paragraphs disclose an independent concept. The applicant reserves the right to file divisional applications according to each inventive concept. Throughout the text, the features guided by "preferably" are only an optional way and should not be understood as must be set. Therefore, the applicant reserves the right to abandon or delete the relevant preferred features at any time.

Claims

1. A biological 3D printing system, comprising: The first unit (100) is used to store the ink with solid particles. The third unit (300) is used to eject the ink to print and form a 3D structure. It is characterized in that the bio-3D printing system is configured with a second unit (200) arranged horizontally for preprocessing the ink. The second storage part (5) of the second unit (200) can receive and store the ink flowing out of the first unit (100), and output the ink to the third unit (300) when there is a printing requirement. Wherein, the second storage part (5) can at least make the upward lifting speed of the ink greater than or equal to the precipitation speed of at least part of the solid particles in the ink by rotating along the axis during the period of storing the ink in the second unit (200) to perform preprocessing of the ink. An active part (6) driven by a second motor (7) to move along the axis of the second storage part (5) is arranged in the second storage part (5). The active part (6) can move in a direction away from the opening to introduce the ink into the second storage part (5) with a tendency to increase the storage space, and the active part (6) can move in a direction close to the opening to discharge the ink from the second storage part (5) with a tendency to decrease the storage space. A collection unit (500) for obtaining data information related to the solid particles in the ink can be arranged on the first communication part (14) connecting the first unit (100) and the second unit (200). Wherein, the data information related to the solid particles at least includes the particle number and / or the particle size. The control unit (400) can at least adjust the output power of the second motor (7) based on the data information related to the solid particles obtained by the collection unit (500) and / or the physical and chemical properties of the ink, and drive the active part (6) to move in the second storage part (5) in a direction away from the opening at a uniform or non-uniform pulling speed.

2. The biological 3D printing system according to claim 1, characterized in that The second storage part (5) can rotate around the axis driven by a third motor (8). Wherein, the third motor (8) is controlled by a control signal generated by the control unit (400) to drive the second storage part (5) to perform one-way continuous rotation or two-way swinging rotation.

3. The biological 3D printing system according to claim 2, characterized in that The second unit (200) is connected to the first unit (100) and the third unit (300) through different communication parts respectively. Wherein, on each communication part, a switching part independently connected to the control unit (400) by a signal is correspondingly arranged, and all the switching parts in response to the control signal of the control unit (400) can be arranged in a way that they are not in the connected state at the same time.

4. The biological 3D printing system according to claim 1, characterized in that The first unit (100) is configured with a first storage part (10) for containing the ink, and a stirring blade (12) driven by a first motor (13) to rotate can be arranged in the first storage part (10).

5. The biological 3D printing system according to claim 4, characterized in that The first storage part (10) is provided with a gas valve (11) limited to open unidirectionally. Wherein, the opening degree of the gas valve (11) can be adjusted at least based on the change of the stirring mode of the stirring blade (12).

6. The biological 3D printing system according to claim 1, characterized in that The third unit (300) is configured with a nozzle (1) arranged in the vertical direction, and the temperature of the ink ejected from the nozzle (1) towards the forming platform (16) is adjusted by at least a temperature control component (2). Among them, the moving component configured in the third unit (300) can adjust the relative position relationship between the nozzle (1) and the forming platform (16).

7. A biological 3D printing method using the biological 3D printing system according to any one of claims 1 to 6, characterized in that The biological 3D printing method includes the following steps: During the feeding process of the second unit (200), the movable member (6) moves away from the opening in a direction to increase the storage space to introduce the ink into the second storage part (5); During the ink storage process of the second unit (200), the second storage part (5) rotates around the axis to drive the ink in the second storage part (5) to rotate, and the second storage part (5) can rotate in a manner that makes the upward lifting speed of the ink greater than or equal to the precipitation speed of at least part of the solid particles in the ink; During the discharging process of the second unit (200), the movable member (6) moves towards the opening in a direction to reduce the storage space to discharge the ink from the second storage part (5), wherein, at least the feeding process, ink storage process and / or discharging process of the second unit (200) can be adjusted by a control signal generated by the control unit (400).

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