3D printing device for multi-material medical model and cross-scale color and texture mapping method

Abstract

The invention relates to the technical field of 3D printing devices, in particular to a 3D printing device for a multi-material medical model and a cross-scale color and texture mapping method.The 3D printing device comprises a shell, a control unit, a support, a displacement assembly, a printing assembly and a fixing plate; the control unit is used for directly converting anatomical information in the medical image data into a 3D printing instruction and then controlling the displacement assembly and the printing assembly to print a medical model; the support is installed in the shell, the displacement assembly is installed on the support, and the displacement assembly is used for controlling the printing assembly to freely move in a two-dimensional space; the printing assembly is installed on the displacement assembly, and the printing assembly is used for printing according to an instruction received by the control unit, and meanwhile, self-cleaning can be achieved after printing is completed; and the fixing assembly is installed at the inner bottom of the shell and used for fixing a printed finished product, and meanwhile, the fixing assembly is adjusted along with the printing assembly in a self-adaptive mode.

Description

Technical Field

[0001] This invention relates to the field of 3D printing device technology, specifically to a 3D printing device for multi-material medical models and a cross-scale color and texture mapping method. Background Technology

[0002] With the rapid development of precision medicine and personalized medicine, high-fidelity 3D printing of medical models based on medical imaging data such as CT and MRI has become a key technological support for preoperative planning, surgical simulation, and medical education. Multi-material 3D printing, due to its ability to simultaneously construct composite structures of hard tissues (such as bone) and soft tissues (such as muscle and blood vessels) with biomechanical gradient differences, is gradually replacing single-material models and becoming the mainstream development direction for improving the anatomical fidelity of medical models. The core of this process lies in the fact that the printing device must directly convert the grayscale information, anatomical boundaries, and functional areas in medical images into voxel-level printing instructions of multiple materials and colors. Any material switching lag, temperature fluctuations, or nozzle blockage will lead to model texture distortion, color shift, or structural defects, directly affecting the accuracy of clinical decisions.

[0003] Existing multi-material 3D printing systems generally adopt a discrete structural design, modularly separating material supply, melt extrusion, and nozzle cleaning functions. The material conveying device only handles material transport, and nozzle maintenance relies on offline cleaning equipment independent of the printing station. This discrete architecture has the following technical bottlenecks: the material transmission path from the storage bin to the print head is long and involves many interfaces; when switching between different materials, residual material remains in dead zones in the pipeline, leading to cross-contamination and waste of expensive consumables such as medical-grade photosensitive resin; at the same time, when printing is paused or after the task is completed, the nozzle is exposed to ambient light and air, and photosensitive materials are prone to solidification and nozzle blockage, lacking in-situ, real-time composite cleaning methods.

[0004] Therefore, the present invention provides a 3D printing device for multi-material medical models and a cross-scale color and texture mapping method to solve the above problems. Summary of the Invention

[0005] The technical problem to be solved by this invention is as follows: Existing 3D printing systems have the following technical bottlenecks: the material transmission path from the storage bin to the printer head is long and there are many interfaces; when switching between different materials, residual material is retained in the dead zone of the pipeline, resulting in cross-contamination and waste of expensive consumables such as medical-grade photosensitive resin; at the same time, when printing is paused or the task is completed, the nozzle is exposed to ambient light and air, and the photosensitive material is prone to solidification and clogging of the nozzle, and there is a lack of in-situ, real-time composite cleaning methods.

[0006] This invention provides the following technical solution: a 3D printing device for multi-material medical models, comprising a shell, a control unit, a support, a displacement component, a printing component, and a fixing plate. The control unit is disposed on top of the shell, and is used to directly convert anatomical information from medical imaging data into 3D printing instructions, then control the displacement component and the printing component to print the medical model. The support is installed inside the shell, and the displacement component is mounted on the support, controlling the printing component to move freely in two-dimensional space. The printing component is mounted on the displacement component, and is used to print according to the instructions received by the control unit, while also achieving self-cleaning after printing. The fixing component is installed at the bottom inside the shell, fixing the printed product and adaptively adjusting along with the printing component.

[0007] Preferably, the displacement assembly includes a fixed block, a displacement screw, a displacement nut, a displacement block, a limit rod, and a displacement motor. The fixed block is fixedly mounted on the bracket. The displacement screw is rotatably mounted on the fixed block. The displacement nut is mounted on the displacement screw. The displacement block is mounted on the displacement nut. Limit rods are symmetrically mounted on the displacement block. The displacement motor is mounted on one end of the displacement screw. The displacement motor is fixedly mounted on the bracket.

[0008] Preferably, the displacement component is provided in three groups, two of which control the lateral and longitudinal movement of the printing component respectively, and the third group controls the up and down movement of the fixing plate.

[0009] Preferably, the printing assembly includes a material storage device, a feeding motor, a limiting plate, a discharge port, a feeding port, a material leveling mechanism, a clamping block, and a printer head. The material storage device is fixedly installed on one side of the bracket. The feeding motor is installed above the material storage device and fixedly installed on the bracket. The limiting plate is installed on one side of the feeding motor and fixedly installed on the bracket. The limiting plate has a discharge port for discharging material. The clamping block is slidably installed on the limiting rod. The clamping block has a feeding port. A material leveling mechanism is fixedly installed below the feeding port. A printer head is arranged below the material leveling mechanism.

[0010] Preferably, the material leveling mechanism includes a material leveling cylinder, a heating block, a heat dissipation block, a heat dissipation cylinder, and a cooling fan. The material leveling cylinder is fixedly installed below the feed inlet, and a heating block for heating the printing consumables is fixedly installed at the bottom of the material leveling cylinder. A heat dissipation block is fixedly installed on the outside of the material leveling cylinder, and heat dissipation cylinders are fixedly installed on both sides of the heat dissipation block. A cooling fan is fixedly installed at the end of the heat dissipation cylinder.

[0011] Preferably, the printer head is fixedly installed below the feed cylinder, and the heating block is located outside the printer head.

[0012] Preferably, an ultrasonic vibrator is installed on the printer head, and an air inlet is connected to one side of the printer head. An air pipe is installed on the air inlet, and the air pipe is used to fill the printer head with inert gas.

[0013] Preferably, the ultrasonic oscillator is a piezoelectric ceramic ring, which is sleeved on the outer wall of the printer head and axially spaced from the heating block, and the vibration frequency of the piezoelectric ceramic ring is 28kHz-40kHz.

[0014] A method for cross-scale color and texture mapping in 3D printing of multi-material medical models is as follows: S1: Receive medical image DICOM data through the control unit, perform threshold segmentation based on Hounsfield units, extract the boundary contours of hard tissue, soft tissue and lesion areas, generate a tomographic bitmap stack containing anatomical structure hierarchical information, and set the Z-axis resolution of the bitmap stack to a slice thickness parameter of 27μm consistent with the step accuracy of the displacement motor. S2: Input the bitmap stack into the cross-scale mapping engine, assign the highest gray value to the hard tissue region and map it to the first heating block temperature setting of the printer head, assign the middle gray value to the soft tissue region and map it to the second heating block temperature setting, assign the lowest gray value to the cavity region and map it to the inert gas purging state, and generate the material ID, RGB color value and transparency triple attribute code for each voxel. S3: According to the triple attribute code, the printing consumables corresponding to hard tissue, soft tissue and support structure are respectively transported through at least three mutually isolated hoppers of the material storage device. The consumables are pressed into the uniform cylinder through the discharge port and the inlet port by the material conveying motor. The material temperature is stabilized within ±0.5℃ of each temperature range by the coordinated action of the cooling fan and the heating block. At the same time, the displacement motor drives the printer head to print the current layer according to the linkage trajectory of the two sets of horizontal and vertical displacement components. S4: When printing the gradient interface inside the same anatomical structure, the control unit adjusts the piezoelectric ceramic ring to vibrate at a frequency of 28kHz-40kHz, so that the material is mixed at the micron level in the uniform cylinder. The rotation speed of the rotary ceramic distribution valve is adjusted synchronously to achieve micro-material ratio switching of 0.1μL / s. Step S3 is repeated every 27μm movement of the displacement motor in the Z-axis direction to complete the cross-scale texture mapping from macroscopic anatomical morphology to microscopic material gradient. S5: When the printing task is paused or completed, the ultrasonic oscillator is activated to perform a 120-second dry-print cleaning of the print head. At the same time, 5kPa-10kPa nitrogen gas is introduced through the air tube and air inlet to blow out the molten material inside the print head. Meanwhile, an inert gas protective layer is formed at the bottom of the consumable to prevent photosensitive resin consumables from curing and clogging under medical ambient light.

[0015] The beneficial effects of this invention are as follows: 1. This invention directly converts medical imaging data into 3D printing instructions through a control unit, driving three sets of lead screw and nut type displacement components to achieve high-precision lateral and longitudinal movement of the printing components and vertical lifting of the fixing plate. This shortens the multi-material conveying path to a direct connection structure of the storage device - limiting plate outlet - clamping block inlet, avoiding cross-contamination and waste of medical-grade consumables caused by dead zones in the pipeline. Simultaneously, the material equalization mechanism adopts an axial complementary temperature control layout of heating block and heat dissipation block - heat dissipation cylinder - cooling fan, forming a constant uniform temperature field outside the print head to ensure stable viscosity of the molten material and improve... Consistent microstructure; the axially continuous structure with the print head fixed below the uniform material cylinder, combined with the axially spaced piezoelectric ceramic ring and heating block, eliminates the risk of material cooling, solidification, and blockage. On the other hand, through the linkage cleaning mechanism of 28kHz-40kHz ultrasonic oscillation and inert gas inlet, a composite cleaning of residual material stripping and gas purging is achieved in situ at the printing station. Materials can be quickly switched without offline maintenance, significantly improving the reliability, aseptic compatibility, and anatomical structure fidelity of continuous printing of multi-material medical models, meeting the stringent requirements of clinical preoperative planning for model accuracy and operational efficiency.

[0016] 2. This invention directly analyzes medical image data through the control unit and drives the linkage of three sets of displacement components. Combined with the independent hopper of the storage device and the array of discharge ports of the limiting plate, it shortens the material transmission path, avoids dead zones in the pipeline, significantly reduces the risk of cross-contamination of medical-grade photosensitive resin and waste of consumables, and meets the stringent requirements of medical models for material purity.

[0017] 3. This invention employs a three-axis displacement system driven by a lead screw and nut, where the XY axes control the printing components and the Z axis independently controls the lifting and lowering of the fixed plate. Combined with the guiding constraint of the limit rod, it achieves a repeatability positioning accuracy of ±0.05mm. The heating block and cooling fan of the material feeding mechanism form a closed-loop temperature control field around the material feeding cylinder, ensuring that the printing consumables maintain a constant melt viscosity at the extrusion head. This allows for the synchronous and accurate mapping of macroscopic anatomical structure and microscopic material texture characteristics to the model voxel-level spatial coordinates. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the process of the present invention; Figure 2 This is a schematic diagram of the displacement component of the present invention; Figure 3 This is a schematic diagram of the printing component of the present invention; Figure 4 This is a schematic diagram of the inlet installation position of the present invention; Figure 5 This is a schematic diagram of the material leveling mechanism of the present invention; Figure 6 This is a schematic diagram of the printer head of the present invention; Figure 7 This is a schematic diagram of the method flow of the present invention.

[0020] In the diagram: 1. Outer shell; 2. Control unit; 3. Bracket; 4. Displacement assembly; 41. Fixing block; 42. Displacement screw; 43. Displacement nut; 44. Displacement block; 45. Limiting rod; 46. Displacement motor; 5. Printing assembly; 51. Material storage device; 52. Material conveying motor; 53. Limiting plate; 54. Discharge port; 55. Inlet port; 56. Material leveling mechanism; 561. Material leveling cylinder; 562. Heating block; 563. Heat dissipation block; 564. Heat dissipation cylinder; 565. Cooling fan; 57. Clamping block; 58. Printer head; 581. Ultrasonic vibrator; 582. Air inlet; 583. Air pipe; 6. Fixing plate. Detailed Implementation

[0021] like Figures 1 to 7 As shown, a 3D printing device for multi-material medical models includes a housing 1, a control unit 2, a support 3, a displacement component 4, a printing component 5, and a fixing plate 6. The control unit 2 is located on top of the housing 1. The control unit 2 directly converts anatomical information from medical imaging data into 3D printing instructions, then controls the displacement component 4 and the printing component 5 to print the medical model. The support 3 is installed inside the housing 1, and the displacement component 4 is mounted on the support 3. The displacement component 4 controls the free movement of the printing component 5 in two-dimensional space. The printing component 5 is mounted on the displacement component 4 and prints according to the instructions received from the control unit 2. It also self-cleanes after printing. The fixing plate 6 is installed at the bottom inside the housing 1. The fixing plate 6 fixes the printed product and adaptively adjusts with the printing component 5. Through modular series connection of pretreatment tank 1, ozone aeration device 3, evaporation device 4, condensation device 5, and adsorption filtration device 6, the four-step integration of "coagulation-catalytic oxidation-self-cleaning evaporation-deep adsorption" is completed in the same closed system. The scraper 453 and heating tube 444 are coaxially positioned to achieve online descaling, maintain a constant heat transfer coefficient, and extend the continuous evaporation cycle by 3 times. The U-shaped heating tube 444 and the baffle 443 form a two-way heat exchange, reuse the heat source, and save more than 10% of energy. The steam outlet 46 filter screen 461 intercepts salt particles and avoids scale formation on the condenser. The cooling component 54 shell-tube array plus fixed support 3544 achieves instantaneous condensation below 45℃, and the cooling water is closed-loop with zero water consumption. The oscillating adsorption increases the COD adsorption capacity by 20%, and the effluent is stable at <500 mg / L. The removable cover and the array cooling tube 543 can be disassembled and installed online, reducing maintenance time by 80%. The whole system achieves efficient, low-consumption, long-term stable treatment and reuse of high-salt and high-COD wastewater.

[0022] like Figures 1 to 2 As shown, the displacement assembly 4 includes a fixed block 41, a displacement screw 42, a displacement nut 43, a displacement block 44, a limiting rod 45, and a displacement motor 46. The fixed block 41 is fixedly installed on the bracket 3. The fixed block 41 is used to fix the displacement screw 42 on the bracket 3 and limit the displacement screw 42, allowing the displacement screw 42 to rotate within the fixed block 41. The displacement screw 42 is rotatably mounted on the fixed block 41. The displacement screw is used to cooperate with the displacement nut 43 to realize the movement of the displacement block 44. The displacement nut 43 is installed on the displacement screw 42, and the displacement block 44 is installed on the displacement nut 43. The movement of the displacement block 44 drives the limiting rod 45 to move. The limiting rod 45 is symmetrically installed on the displacement block 44. The movement of the limiting rod 45 drives the clamping block 57 to move. The displacement motor 46 is installed at one end of the displacement screw 42 and is fixedly installed on the bracket 3. The displacement motor 46 is used to drive the displacement screw 42 to rotate. During operation, the operator starts the displacement motor 46, which drives the displacement screw 42 to rotate. The rotation of the displacement screw 42 drives the displacement block 44 to move, which in turn drives the clamping block 57 to move through the limit rod 45. It should be noted that the displacement components 4 in the same direction are all in pairs, that is, they are installed on both sides of the bracket 3. The above design uses the fixed block 41 to provide dual constraints on the rotation limit and axial fixation of the displacement screw 42. Combined with the precision thread transmission of the displacement screw 42 and the displacement nut 43, the rotational motion is converted into the high-precision linear displacement of the displacement block 44. The limiting rods 45 symmetrically arranged on the displacement block 44 form a double-sided guide support, which effectively avoids the deflection and vibration problems caused by the cantilever structure. At the same time, the mirror symmetrical layout of two groups in the same direction makes the printing component 5 subjected to balanced force and enhanced rigidity during movement, which significantly improves the repeatability and motion stability of the two-dimensional plane positioning. It is especially suitable for the requirements of precise positioning of fine structures in medical model printing.

[0023] like Figures 1 to 2 As shown, the displacement component 4 is provided in three groups, two of which control the lateral and longitudinal movement of the printing component 5 respectively, and the third group controls the vertical movement of the fixing plate 6. The design decouples the functions of the three displacement components 4, so that the printing component 5 only needs to undertake the relatively light lateral and longitudinal two-dimensional movement, while the vertical lifting of the fixing plate 6 is independently controlled by the third displacement component 4. This effectively avoids the problems of large motion inertia and slow dynamic response caused by the integrated Z-axis drive mechanism of the print head in traditional three-axis linkage, and significantly improves the acceleration and deceleration performance and positioning accuracy of the printing component 5. At the same time, the fixing plate 6 has a unique Z-axis displacement system and can adopt a high-rigidity support structure to ensure the stability and repeatability of layer height control during the medical model printing process. It is particularly suitable for the stringent requirements of microscale layer thickness consistency in the multi-material layer manufacturing of complex anatomical structures.

[0024] like Figures 1 to 6 As shown, the printing assembly 5 includes a material storage device 51, a feeding motor 52, a limiting plate 53, a discharge port 54, a feeding port 55, a material leveling mechanism 56, a clamping block 57, and a printing head 58. The material storage device 51 is fixedly installed on one side of the bracket 3 and is used to store raw materials. It is generally a rolling material cylinder, but it can also be adaptively replaced according to different raw materials. The feeding motor 52 is installed above the material storage device 51 and fixedly installed on the bracket 3. The feeding motor 52 is used to transport raw materials to the discharge port 54. The limiting plate 53 is installed on one side of the feeding motor 52 and the limiting plate 53... A limiting plate 53 is fixedly installed on the bracket 3 to limit the material. The limiting plate 53 has a discharge port 54 for discharging material, which works with the feeding motor 52 to discharge material. A clamping block 57 is slidably installed on the limiting rod 45. The clamping block 57 has a feeding port 55 for conveying the material to the leveling mechanism 56. The leveling mechanism 56 is fixedly installed below the feeding port 55 and is used to evenly distribute the material to the printer head 58. The printer head 58 is located below the leveling mechanism 56 and is used for printing. The staff loads the cartridge containing medical-grade printing consumables into the storage device 51 and starts the feeding motor 52. The feeding motor 52 pushes the raw material to the discharge port 54 at the limiting plate 53. At the same time, the clamping block 57 slides along the limiting rod 45 to align the inlet 55 with the discharge port 54. The raw material enters the leveling mechanism 56 through the inlet 55. The leveling mechanism 56 evenly extrudes the heated and melted consumables into the printer head 58. After the printing component 5 moves to the designated coordinate, the printer head 58 begins to deposit and form layers one by one. When printing is paused or the task is completed, the feeding motor 52 reverses to pull back the residual material in the pipeline and, together with the ultrasonic oscillator 581, cleans the printer head 58 in situ. The design, through the direct connection between the feeding motor 52 and the discharge port 54 of the limiting plate 53, combined with the sliding alignment mechanism of the clamping block 57 on the limiting rod 45, significantly shortens the transmission path of medical-grade consumables from storage to extrusion, reduces dead zone residue in the pipeline, and achieves active retraction of residual material by controlling the forward and reverse rotation of the feeding motor 52, effectively avoiding cross-contamination between different materials and waste of expensive consumables; at the same time, the vertical integration of the material leveling mechanism 56 and the printer head 58 enables the continuous completion of material melting, homogenization, and extrusion in the same axis, improving printing efficiency.

[0025] like Figures 1 to 6 As shown, the material leveling mechanism 56 includes a material leveling cylinder 561, a heating block 562, a heat dissipation block 563, a heat dissipation cylinder 564, and a cooling fan 565. The material leveling cylinder 561 is fixedly installed below the feed inlet 55 and is used to uniformly heat the raw material. The heating block 562 is fixedly installed at the bottom of the material leveling cylinder 561 to heat the printing consumables. The heating block 562 is used to heat and melt the raw material. The heat dissipation block 563 is fixedly installed on the outside of the material leveling cylinder 561 and is used to transfer heat to the inside of the heat dissipation cylinder 564. The heat dissipation cylinder 564 is fixedly installed on both sides of the heat dissipation block 563 and is used to cooperate with the cooling fan 565 to achieve heat dissipation. The cooling fan 565 is fixedly installed at the end of the heat dissipation cylinder 564 and is used to dissipate heat from the entire printing assembly 5.

[0026] During operation, the operator starts the feeding motor 52 to feed the raw material into the uniform material cylinder 561 through the feed port 55. At the same time, the heating block 562 continuously heats and melts the printing consumables at the bottom of the uniform material cylinder 561, so that the raw material forms a uniform molten state in the uniform material cylinder 561. After the raw material is completely melted, the heat dissipation block 563 conducts the excess heat from the outer wall of the uniform material cylinder 561 to the heat dissipation cylinder 564, and under the forced convection of the cooling fan 565, the heat is discharged to the outside of the printing component 5, keeping the internal temperature of the uniform material cylinder 561 constant. After the temperature stabilizes, the uniformly molten material is extruded through the print head 58 for layer-by-layer deposition. The above design achieves point-to-point melting of raw materials by setting a heating block 562 at the bottom of the uniform material cylinder 561. At the same time, a step-by-step heat conduction and forced convection heat dissipation system consisting of a heat dissipation block 563, a heat dissipation cylinder 564, and a heat dissipation fan 565 is configured outside the uniform material cylinder 561. This forms a complementary thermal management architecture for heating and heat dissipation functions in the axial and circumferential directions. It effectively avoids the problem of uneven temperature gradient or local overheating caused by traditional sidewall heating, ensuring that the medical-grade printing consumables maintain a constant melt viscosity in the uniform material cylinder 561. It prevents sudden changes in material flowability or thermal degradation caused by temperature fluctuations, thereby continuously delivering molten material with stable molding performance to the print head 58. This significantly improves the consistency of interlayer bonding strength and microstructure accuracy in multi-material medical models.

[0027] like Figures 1 to 6 As shown, the printer head 58 is fixedly installed below the uniform feed cylinder 561, and the heating block 562 is located outside the printer head 58. The design, by directly fixing the printer head 58 below the uniform feed cylinder 561 and placing the heating block 562 outside the printer head 58, forms an axial continuous layout of melting-conveying-extrusion. This significantly shortens the residence path of the high-temperature molten material from the heating zone to the nozzle outlet, reduces pipeline dead zones and heat loss, and avoids the risk of blockage caused by material cooling and solidification in traditional side-mounted or separate structures. At the same time, the external installation of the heating block 562 facilitates real-time temperature control and heat radiation protection. Combined with the synergistic effect of the heat dissipation system, it makes the temperature gradient distribution on the outer wall of the printer head 58 more uniform, ensuring that temperature-sensitive materials such as medical-grade photosensitive resin maintain stable rheological properties during extrusion, thereby improving the accuracy and repeatability of multi-material medical models in mapping microstructure and macroscopic mechanical properties.

[0028] like Figures 1 to 6As shown, an ultrasonic vibrator 581 is installed on the print head 58, and an air inlet 582 is connected to one side of the print head 58. The air inlet is normally closed; only after printing is completed is inert gas introduced into the print head 58 through an air pipe 583 to clean any remaining material inside. An air pipe 583 is installed on the air inlet 582, used to introduce inert gas into the print head 58, and the inert gas also protects the end of the material. The print head 58 integrates the ultrasonic vibrator 581 and the normally closed inert gas inlet 582, which is activated after printing is completed. Ultrasonic vibration loosens residual material and simultaneously opens the air inlet 582 to introduce inert gas for purging and rinsing. This achieves dual mechanical and pneumatic cleaning at the printing station, thoroughly removing residual material without disassembling the printhead and significantly reducing equipment downtime for maintenance. At the same time, the inert gas creates an inert environment to protect the inside of the printhead 58 and the material end during the cleaning process, effectively isolating oxygen and ambient light and preventing the medical-grade photosensitive resin from curing and clogging the nozzles. This significantly improves the ability to prevent cross-contamination during multi-material switching and extends the lifespan of the printhead, ensuring the reliability of continuous printing of medical models and meeting the requirements of a sterile operating environment.

[0029] like Figures 1 to 6 As shown, the ultrasonic oscillator is a piezoelectric ceramic ring, which is sleeved on the outer wall of the printer head 58 and axially spaced from the heating block 562. The vibration frequency of the piezoelectric ceramic ring is 28kHz-40kHz. Using the piezoelectric ceramic ring as the ultrasonic oscillator 581 and sleeved on the outer wall of the printer head 58, and axially spaced from the heating block 562, high-frequency mechanical vibration is generated in the frequency range of 28kHz-40kHz. The ultrasonic cavitation effect is used to effectively peel off and crush the medical-grade photosensitive resin residue in the inner cavity and nozzle of the printer head 58. At the same time, the axial isolation design avoids mutual interference between ultrasonic vibration and heat conduction of the heating block 562, which not only ensures the temperature stability of melt extrusion, but also realizes in-situ non-destructive cleaning of the printing station. This significantly improves the ability to prevent cross-contamination during multi-material switching and the anti-clogging performance of the printhead, and extends the service life of the precision printer head 58.

[0030] like Figure 7 As shown, a method for cross-scale color and texture mapping in 3D printing of multi-material medical models is as follows: S1: Receive medical image DICOM data through control unit 2, perform threshold segmentation based on Hounsfield units, extract the boundary contours of hard tissue, soft tissue and lesion areas, generate a tomographic bitmap stack containing anatomical structure hierarchical information, and set the Z-axis resolution of the bitmap stack to a slice thickness parameter of 27μm consistent with the 46-step accuracy of the displacement motor. S2: Input the bitmap stack into the cross-scale mapping engine, assign the highest gray value to the hard tissue region and map it to the temperature setting of the first heating block 562 of the printer head 58, assign the intermediate gray value to the soft tissue region and map it to the temperature setting of the second heating block 562, assign the lowest gray value to the cavity region and map it to the inert gas purging state, and generate the material ID, RGB color value and transparency triple attribute code for each voxel; S3: According to the triple attribute code, the printing consumables corresponding to hard tissue, soft tissue and support structure are respectively transported through at least three mutually isolated hoppers of the material storage device 51. The material is pressed into the uniform cylinder 561 through the discharge port 54 and the inlet port 55 by the material conveying motor 52. The material temperature is stabilized within ±0.5℃ of each temperature range by the coordinated action of the cooling fan 565 and the heating block 562. At the same time, the displacement motor 46 drives the printer head 58 to print the current layer according to the linkage trajectory of the two sets of horizontal and vertical displacement components 4. S4: When printing the gradient interface inside the same anatomical structure, the control unit 2 adjusts the piezoelectric ceramic ring to vibrate at a frequency of 28kHz-40kHz, so that the material is mixed at the micron level in the uniform cylinder 561. The rotation speed of the rotary ceramic distribution valve is adjusted synchronously to achieve micro-material ratio switching of 0.1μL / s. Step S3 is repeated every 27μm when the displacement motor 46 moves in the Z-axis direction, so as to complete the cross-scale texture mapping from macroscopic anatomical morphology to microscopic material gradient. S5: When the printing task is paused or completed, the ultrasonic oscillator is started to perform a 120-second dry-print cleaning of the print head 58. At the same time, 5kPa-10kPa nitrogen gas is introduced through the air tube 583 and air inlet 582 to blow out the molten material inside the print head 58. Meanwhile, an inert gas protective layer is formed at the bottom of the consumable to prevent photosensitive resin consumables from curing and clogging under medical ambient light.

[0031] The overall working process is as follows: The operator loads the material cylinder containing medical-grade printing consumables into the storage device 51 and starts the conveying motor 52. The conveying motor 52 presses the material into the uniform material cylinder 561 through the discharge port 54 of the limiting plate 53 and the inlet 55 of the clamping block 57. At the same time, the heating block 562 continuously heats and melts the printing consumables at the bottom of the uniform material cylinder 561. The cooling fan 565 dissipates excess heat through the heat dissipation block 563 and the heat dissipation cylinder 564 to maintain a constant internal temperature of the uniform material cylinder 561. After the material is completely melted, the displacement motor 46 drives the displacement screw 42 to move... Under the guidance of the limiting rod 45, the clamping block 57 moves horizontally and vertically in two dimensions. At the same time, the third set of displacement components 4 controls the fixing plate 6 to lift and lower in the Z direction. The printer head 58 deposits the uniformly molten material layer by layer. When printing is paused or the task is completed, the feeding motor 52 reverses to draw back the residual material in the pipeline and starts the piezoelectric ceramic ring to perform ultrasonic vibration cleaning of the printer head 58 at a frequency of 28kHz-40kHz. At the same time, the air inlet 582 is opened and inert gas is introduced into the printer head 58 through the air pipe 583 to blow away the residual material, realizing in-situ self-cleaning of the printing station.

[0032] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A 3D printing device for multi-material medical models, characterized in that, The device includes a housing (1), a control unit (2), a support (3), a displacement component (4), a printing component (5), and a fixing plate (6). The control unit (2) is located on the top of the housing (1). The control unit (2) is used to directly convert anatomical information in medical image data into 3D printing instructions and then control the displacement component (4) and the printing component (5) to print the medical model. The support (3) is installed inside the housing (1), and the displacement component (4) is installed on the support (3). The displacement component (4) is used to control the printing component (5) to move freely in two-dimensional space. The printing component (5) is installed on the displacement component (4). The printing component (5) is used to print according to the instructions received by the control unit (2) and can achieve self-cleaning after printing. The fixing component is installed at the bottom inside the housing (1). The fixing component is used to fix the printed product and also adapts to the printing component (5).

2. The 3D printing device for multi-material medical models according to claim 1, characterized in that: The displacement assembly (4) includes a fixed block (41), a displacement screw (42), a displacement nut (43), a displacement block (44), a limit rod (45), and a displacement motor (46). The fixed block (41) is fixedly installed on the bracket (3). The displacement screw (42) is rotatably installed on the fixed block (41). The displacement nut (43) is installed on the displacement screw (42). The displacement block (44) is installed on the displacement nut (43). The limit rod (45) is symmetrically installed on the displacement block (44). The displacement motor (46) is installed at one end of the displacement screw (42). The displacement motor (46) is fixedly installed on the bracket (3).

3. The 3D printing device for multi-material medical models according to claim 2, characterized in that: The displacement component (4) is provided in three groups, two of which control the horizontal and vertical movement of the printing component (5) respectively, and the third group controls the vertical movement of the fixing plate (6).

4. The 3D printing device for multi-material medical models according to claim 3, characterized in that: The printing assembly (5) includes a storage device (51), a feeding motor (52), a limiting plate (53), a discharge port (54), a feed port (55), a leveling mechanism (56), a clamping block (57), and a printer head (58). The storage device (51) is fixedly installed on one side of the bracket (3). The feeding motor (52) is installed above the storage device (51) and fixedly installed on the bracket (3). The limiting plate (53) is installed on one side of the feeding motor (52) and fixedly installed on the bracket (3). The limiting plate (53) has a discharge port (54) for discharging material. The clamping block (57) is slidably installed on the limiting rod (45). The clamping block (57) has a feed port (55). The leveling mechanism (56) is fixedly installed below the feed port (55). The printer head (58) is located below the leveling mechanism (56).

5. The 3D printing device for multi-material medical models according to claim 4, characterized in that: The material feeding mechanism (56) includes a material feeding cylinder (561), a heating block (562), a heat dissipation block (563), a heat dissipation cylinder (564), and a cooling fan (565). The material feeding cylinder (561) is fixedly installed below the feed inlet (55). A heating block (562) for heating the printing consumables is fixedly installed at the bottom of the material feeding cylinder (561). A heat dissipation block (563) is fixedly installed on the outside of the material feeding cylinder (561). A heat dissipation cylinder (564) is fixedly installed on both sides of the heat dissipation block (563). A cooling fan (565) is fixedly installed at the end of the heat dissipation cylinder (564).

6. The 3D printing device for multi-material medical models according to claim 5, characterized in that: The printer head (58) is fixedly installed below the feed cylinder (561), and the heating block (562) is located outside the printer head (58).

7. The 3D printing device for multi-material medical models according to claim 6, characterized in that: An ultrasonic vibrator (581) is installed on the printer head (58), and an air inlet (582) is connected to one side of the printer head (58). An air pipe (583) is installed on the air inlet (582), and the air pipe (583) is used to fill the printer head (58) with inert gas.

8. The 3D printing device for multi-material medical models according to claim 7, characterized in that: The ultrasonic oscillator (581) is a piezoelectric ceramic ring, which is sleeved on the outer wall of the printer head (58) and axially spaced from the heating block (562). The vibration frequency of the piezoelectric ceramic ring is 28kHz-40kHz.

9. A method for cross-scale color and texture mapping in 3D printing of multi-material medical models, characterized in that, The apparatus for 3D printing multi-material medical models, as described in any one of claims 1 to 8, comprises the following method: S1: Receive medical image DICOM data through the control unit (2), perform threshold segmentation based on Hounsfield units, extract the boundary contours of hard tissue, soft tissue and lesion areas, generate a tomographic bitmap stack containing anatomical structure hierarchical information, and set the Z-axis resolution of the bitmap stack to a layer thickness parameter of 27μm consistent with the step accuracy of the displacement motor (46). S2: Input the bitmap stack into the cross-scale mapping engine, assign the highest gray value to the hard tissue region and map it to the temperature range of the first heating block (562) of the printer head (58), assign the intermediate gray value to the soft tissue region and map it to the temperature range of the second heating block (562), assign the lowest gray value to the cavity region and map it to the inert gas purging state, and generate the material ID, RGB color value and transparency triple attribute code for each element; S3: According to the triple attribute code, the printing consumables corresponding to hard tissue, soft tissue and support structure are respectively transported through at least three mutually isolated hoppers of the material storage device (51). The consumables are pressed into the uniform cylinder (561) through the discharge port (54) and the inlet port (55) by the material conveying motor (52). The material temperature is stabilized within ±0.5℃ of each temperature range by the coordinated action of the cooling fan (565) and the heating block (562). At the same time, the displacement motor (46) drives the printer head (58) to print the current layer according to the linkage trajectory of the two sets of horizontal and vertical displacement components (4). S4: When printing the gradient interface inside the same anatomical structure, the control unit (2) adjusts the piezoelectric ceramic ring to vibrate at a frequency of 28kHz-40kHz, so that the material is mixed at the micron level in the uniform cylinder (561). The rotation speed of the rotary ceramic distribution valve is adjusted synchronously to achieve a micro-material ratio switching of 0.1μL / s. Step S3 is repeated every 27μm movement of the displacement motor (46) in the Z-axis direction to complete the cross-scale texture mapping from macroscopic anatomical morphology to microscopic material gradient. S5: When the printing task is paused or completed, the ultrasonic oscillator is started to perform a 120-second dry cleaning of the printer head (58). At the same time, 5kPa-10kPa nitrogen gas is introduced through the air tube (583) and air inlet (582) to blow out the molten material inside the printer head (58). Meanwhile, an inert gas protective layer is formed at the bottom of the consumable to prevent photosensitive resin consumables from curing and clogging under medical ambient light.

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