A field 3D printing device and printing method

Abstract

The application discloses a kind of on-site 3D printing devices suitable for bone repair internal defect, including rack, three degrees of freedom motion platform, multi-degree-of-freedom suspension movable arm, extrusion printing mechanism, scanning mechanism and operating bed, the three degrees of freedom motion platform is installed on rack top, the multi-degree-of-freedom suspension movable arm is installed three degrees of freedom motion platform, the extrusion printing mechanism is installed on multi-degree-of-freedom suspension movable arm, the scanning mechanism is installed in rack middle end, the rack is installed operating bed.The device can be done to the online scanning of patient wound, utilize wrapping printing technology to repair printing to bone defect, process is simple, need not too many manpower, can also complete the printing problem of irregular internal bone defect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical equipment, in particular to a 3D printing device and method for repairing a sunken defect of a bone. BACKGROUND

[0002] Bone defect is a common orthopedic disease, and its causes are various, which leads to different shapes, sizes and severity of bone defects. The complex condition makes clinical treatment very difficult, and the clinical treatment is often accompanied by long treatment cycle, large surgical trauma, multiple complications and other problems. When performing a traditional repair operation, the shape of the bone defect needs to be scanned first, and then the obtained image is analyzed and processed by professional personnel to model. After the model is established, the artificial bone is prepared in vitro first, and then the doctor performs repeated trimming according to his experience and judgment of the shape of the patient's wound, and then matches the patient after the trimming is completed. The whole process is complicated, the operation cycle is long, and since too much manpower is needed, the accuracy cannot be guaranteed, which often leads to poor treatment effect, and the above process needs to be repeated, which not only wastes materials and time, but also causes secondary trauma to the patient. SUMMARY

[0003] According to the deficiencies of the prior art, the present application provides a 3D printing device and method, which can perform online scanning of the wound of the patient, repair and print the bone defect by using the wrapping printing technology, the process is simple, too much manpower is not needed, and the printing problem of irregular sunken bone defect can be solved.

[0004] In order to solve the above technical problems, the technical scheme of the present application is as follows:

[0005] A 3D printing device, comprising a rack, a three-degree-of-freedom motion platform, a multi-degree-of-freedom suspension movable arm, an extrusion printing mechanism, a scanning mechanism and a surgical bed, the three-degree-of-freedom motion platform is installed on the top of the rack, the multi-degree-of-freedom suspension movable arm is installed on the three-degree-of-freedom motion platform, the extrusion printing mechanism is installed on the multi-degree-of-freedom suspension movable arm, the scanning mechanism is installed on the middle end of the rack, and the rack is installed on the surgical bed.

[0006] As a preferred, the three-degree-of-freedom motion platform comprises a longitudinal linear motor module, a transverse linear motor module and a short vertical short linear module, two longitudinal linear motor modules are arranged in parallel on the top of the rack, a longitudinal sliding block is slidably installed on the longitudinal linear motor module, two longitudinal sliding blocks are fixed at the two ends of the transverse linear motor module, a transverse sliding block is slidably installed on the transverse linear motor module, the short vertical short linear module is fixedly installed on the transverse sliding block, a vertical sliding block is slidably installed on the short vertical short linear module, and the multi-degree-of-freedom suspension movable arm is installed on the vertical sliding block.

[0007] As preferred, the longitudinal linear motor module comprises a servo motor, a transmission belt and a slide rail, the longitudinal slide block is slidably installed on the slide rail, the servo motor is arranged at one end of the slide rail, a roller is arranged at the other end of the slide rail, the transmission belt is wound around the output shaft of the servo motor and the roller shaft, the transmission belt is fixedly connected with the longitudinal slide block, the transverse linear motor module and the short vertical short linear module structure are the same as the longitudinal linear motor module.

[0008] As preferred, the multi-degree-of-freedom suspension movable arm comprises a first connecting rod, a first cylinder, a second connecting rod, a second cylinder and a third connecting rod, one end of the first connecting rod is fixedly installed on the vertical slide block, the other end of the first connecting rod is hingedly connected with the top end of the second connecting rod through a hinge, the top of the first cylinder is fixedly connected to the middle position of the first connecting rod, the power output end of the first cylinder is hingedly connected to the middle position of the second connecting rod through a hinge, the top end of the third connecting rod is connected with the bottom end of the second connecting rod, the top of the second cylinder is fixedly installed on the second connecting rod, the power output end of the second cylinder is hingedly connected to the third connecting rod, and the extrusion printing mechanism is installed at the bottom end of the third connecting rod.

[0009] As preferred, the scanning mechanism comprises a position adjusting mechanism and an image acquisition unit, the position adjusting mechanism comprises a linear module, a first motor, a large gear, a small gear, a ball screw and a screw nut slider, two linear modules are arranged in parallel at the middle position of the rack, the structure of the linear module is the same as that of the longitudinal linear motor module, a connecting slide block is slidably connected to the linear module, first connecting plates are fixedly arranged at the opposite sides of the two connecting slide blocks, a fixed long plate is horizontally installed between the two first connecting plates, the first motor is installed on the upper surface of the fixed long plate, the ball screw is located below the fixed long plate, and both ends of the ball screw are rotatably connected to the two first connecting plates through rotary bearings, the large gear is fixedly arranged at the output end of the first motor, the small gear is fixedly installed on the ball screw, the large gear and the small gear are meshed with each other, and the screw nut slider is threadedly connected to the ball screw.

[0010] As preferred, the image acquisition unit comprises a binocular camera and a grating projector, the binocular camera is installed on the screw nut slider, a telescopic support is arranged on the side wall of the screw nut slider, the grating projector is installed on the telescopic support through a two-degree-of-freedom connecting piece, and the grating projector cooperates with the binocular camera.

[0011] As preferred, the bottom end of the third connecting rod is provided with a universal connecting piece, and the extrusion printing mechanism is installed to the bottom end of the third connecting rod through the universal connecting piece.

[0012] Preferably, the universal connecting piece comprises a second connecting plate, a spherical gear, two mounting seats and two driving mechanisms, one side center of the second connecting plate is fixedly connected to the bottom end of the third connecting rod, the two mounting seats are symmetrically arranged at the middle position of the other side of the second connecting plate, the spherical gear is arranged between the two mounting seats, the two driving mechanisms are symmetrically arranged on the two sides of the spherical gear, the driving mechanism comprises a motor mounting plate fixed on the second connecting plate and a box fixing seat, a rotary gear box is arranged on the box fixing seat, a transmission mechanism is arranged in the rotary gear box, a second motor is arranged on the motor mounting plate, the second motor is connected to the spherical gear through the transmission mechanism, and the extrusion printing mechanism is fixedly arranged on the surface of the spherical gear.

[0013] Preferably, the transmission mechanism comprises a single-pole gear, a transition spur gear, a small spur gear, a second bevel gear, a first bevel gear and a rotary bearing, the second bevel gear is fixedly arranged on the output end of the second motor, the first bevel gear is arranged on the inner wall of the rotary gear box through a connecting shaft, the first bevel gear and the second bevel gear are meshed with each other, the small spur gear is coaxially arranged with the first bevel gear, the transition spur gear is rotatably arranged in the rotary gear box through a connecting shaft, the small spur gear is meshed with the transition spur gear, the transition spur gear is connected to the single-pole gear through the rotary bearing, and the single-pole gear is meshed with the spherical gear.

[0014] The application also provides a 3D printing method, which comprises the following steps:

[0015] 1) The patient with a bone defect lies on the operating bed, the binocular camera and the light barrier projector on the scanning mechanism are driven by the linear motor module and the screw nut slider to reach above the position of the bone defect of the patient, then the two-degree-of-freedom connecting piece and the telescopic support are used to adjust the position and posture of the binocular camera and the light barrier projector, so that the binocular imaging area and the projection area are coincided, the scanning and imaging are ensured to be complete, the shape of the bone defect is scanned through the binocular stereo vision, and the obtained data is transmitted to the computer for 3D modeling, and after the analysis and processing of the scanning data by the computer, the three-dimensional model of the shape of the bone defect is established;

[0016] 2) The entity data of the model is subjected to layering and slicing processing through layering software, corresponding codes are input into the 3D printing device, and the extrusion printing device is used for real-time printing;

[0017] 3) the three degrees of freedom motion platform drives the multi-degree of freedom suspension movable arm to the position of the patient's bone defect part through three-dimensional motion, then the three connecting rods of the multi-degree of freedom suspension movable arm are driven by two cylinders to move relatively to drive the extrusion printing device to a more accurate and suitable pose, then the extrusion printing device starts to work, the spherical gear part connected with the extrusion printing device can make the extrusion printing device print in multiple directions according to the function of arbitrary angle rotation, and the repair printing of the complex bone defect shape is completed.

[0018] The on-site 3D printing device for repairing invagination bone defect can realize the change of the printing needle tube direction according to the actual printing requirement by driving the extrusion printing device to move through the spherical gear joint, solves the limitation of the traditional printing, and solves the difficulty of printing in the side hole type defect.

[0019] The method is simple, easy to operate, low in cost, and the overall structure adopts a double-layer complex structure, the scanning module and the printing module are located in different motion planes, and the movement of each part of the equipment is very flexible. The multi-degree of freedom suspension movable arm has sufficient movement space in the plane and will not interfere with the movement of the scanning module. The multi-degree of freedom suspension movable arm mechanism can meet the requirement of any space movement of the printing head, and the use of the high-cost six-degree of freedom mechanical arm can also achieve the corresponding effect.

[0020] When the device is applied to bone defect repair surgery, 3D printing can be performed in real time according to the on-site state, which not only helps the operation period, but also can be adjusted according to the on-site condition, thereby effectively providing the success rate of the operation. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0022] Figure 1 is a structure schematic view of the on-site 3D printing device of the present application.

[0023] Figure 2 is a mechanism schematic view of the three degrees of freedom motion platform of the present application.

[0024] Figure 3 is a mechanism schematic view of the multi-degree of freedom suspension movable arm of the present application.

[0025] Figure 4 is a mechanism schematic view of the scanning mechanism of the present application.

[0026] Figure 5 is another perspective structural diagram of the application. Figure 4

[0027] Figure 6 is a structural diagram of the spherical gear joint of the application.

[0028] Figure 7 is a structural diagram of the extrusion printing device of the application.

[0029] Figure 8 is a flowchart of the on-site printing method of the application.

[0030] Figure 9 is a printing example diagram of the on-site 3D printing device of the application.

[0031] In the figure: 1-frame, 2-three degree of freedom motion platform, 3-multiple degree of freedom suspension movable arm, 4-scanning mechanism, 5-extrusion printing mechanism, 6-surgical bed trolley, 7-longitudinal linear motor module, 8-lateral linear motor module, 9-vertical short linear module, 10-first connecting rod, 11-first air cylinder, 12-second connecting rod, 13-third connecting rod, 14-second air cylinder, 15-first motor, 16-large gear, 17-linear module, 18-first connecting plate, 19-fixed long plate, 20-small gear, 21-ball screw, 22-screw nut sliding block, 23-binocular camera, 24-raster projector, 25-two degree of freedom connecting piece, 26-telescopic support, 27-spherical gear, 28-monopolar gear, 29-transition spur gear, 30-small spur gear, 31-second bevel gear, 32-first bevel gear, 33-rotary gear box, 34-rotary bearing, 35-mounting seat, 36-box fixing seat, 37-motor mounting plate, 38-second motor, 39-second connecting plate, 40-lightweight connecting piece, 41-penetration motor, 42-printing cylinder bottom cover, 43-printing cylinder, 44-fourth bevel gear, 45-third bevel gear, 46-small shaft, 47-fourth connecting rod, 48-fifth connecting rod, 49-piston, 50-printing nozzle. DETAILED DESCRIPTION

[0032] It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict.

[0033] ​In the description of the present application, it needs to be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and the like can be explicitly or implicitly included one or more. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0034] In the description of the present application, it needs to be understood that unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or indirectly connected through an intermediate medium, it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0035] The present application provides a kind of 3D printing device on site, as shown in Figure 1 It includes rack 1, three degrees of freedom motion platform 2, multi-degree of freedom suspension movable arm 3, extrusion printing mechanism 5, scanning mechanism 4 and operating bed car 6;The three degrees of freedom motion platform 2 of the described is installed on the upper end of rack 1;Multi-degree of freedom suspension movable arm 3 is installed on the three degrees of freedom motion platform 2 described above;Extrusion printing mechanism 5 is installed on multi-degree of freedom suspension movable arm 3;Scanning mechanism 4 is installed in the middle end of rack 1;Operating bed car 6 is fixed in the bottom of rack 1.

[0036] In the above technical solution, the wound of the patient can be scanned on line, and the on-site situation of bone defect is repaired and printed by using wrapping printing technology.

[0037] Further provided in the present application, as shown in Figure 2As shown, the three-degree-of-freedom motion platform 2 includes longitudinal linear motor modules 7 installed on both sides of the frame, transverse linear motor modules 8 installed on the longitudinal linear motor modules 7, and vertical short linear modules 9 installed on the transverse linear motor modules 8. The servo motors of the longitudinal linear motor modules 7 on both sides are started to convert the rotary motion into linear motion to drive the transverse linear motor modules 8 to complete longitudinal motion. Similarly, the transverse linear motor modules 8 drive the vertical short linear modules 9 to complete transverse motion, and the vertical short linear modules 9 can drive the multi-degree-of-freedom suspension movable arm 3 installed thereon to complete vertical motion. Therefore, the multi-degree-of-freedom suspension movable arm 3 can complete simple three-dimensional motion.

[0038] Specifically, the longitudinal linear motor module includes a servo motor, a transmission belt, and a slide rail, the longitudinal slide block is slidably installed on the slide rail, the servo motor is arranged at one end of the slide rail, a roller is arranged at the other end of the slide rail, the transmission belt is wound around the output shaft of the servo motor and the roller, and the transmission belt is fixedly connected with the longitudinal slide block. The structures of the transverse linear motor module and the short vertical short linear module are the same as those of the longitudinal linear motor module.

[0039] It should be noted that in the embodiment, the other structures for converting the rotary motion into linear motion are also applicable.

[0040] Further, as shown in the figure, Figure 3 The multi-degree-of-freedom suspension movable arm 3 includes a first connecting rod 10 installed on the three-degree-of-freedom motion platform 2, a first air cylinder 11 installed on the first connecting rod 10, a second connecting rod 12 hingedly connected with the first air cylinder 11, a second air cylinder 14 installed on the second connecting rod 12, a third connecting rod 13 hingedly connected with the second air cylinder 14, a second connecting plate 39 installed on the third connecting rod 13, a mounting seat 35 installed on the second connecting plate 39, a spherical gear 27 installed on the mounting seat 35, a single-stage gear 28 engaged with the spherical gear 27, a transition straight gear 29 engaged with the single-stage gear 28, a small straight gear 30 engaged with the transition straight gear 29, a bevel gear No. 1 32 coaxially connected with the small straight gear 30, a bevel gear No. 2 31 engaged with the bevel gear No. 1 32, a rotary gear box 33 fixedly connected with the bevel gear No. 2 31, a box fixed seat 36 cooperated with the rotary gear box 33 through a rotary bearing 34, a motor mounting plate 37 installed on the box mounting seat 36, and a motor 38 installed on the motor mounting plate 37.

[0041] In the above technical solution, the first cylinder 11 drives the second connecting rod 12 and the first connecting rod 10 to move relatively to realize bending, the second cylinder 14 drives the third connecting rod 13 and the second connecting rod 12 to move relatively to complete bending, the third connecting rod 13 drives the second connecting plate 39, the second connecting plate 39 drives the mounting seat 35, the mounting seat 35 drives the spherical gear 27 to complete two-dimensional movement in the XOZ plane, the motor 38 drives the bevel gear No. 31 and the rotary gear box 33 to rotate synchronously, the bevel gear No. 31 drives the bevel gear No. 32 to mesh and drive, the bevel gear No. 32 drives the small straight gear 30 to coaxially drive, the small straight gear 30 drives the transition straight gear 29 to mesh and drive, the transition straight gear 29 drives the single-pole gear 28 to mesh and drive, the rotary gear box 33 drives the single-pole gear 28 to rotate synchronously, and the single-pole gear 28 drives the spherical gear 27 to mesh and rotate.

[0042] Further, as shown in Figure 7 The extrusion printing mechanism 5 includes a light connecting piece 40 installed on the spherical gear 27, a printing cylinder bottom cover 42 fixed on the light connecting piece 40, a through motor 41 installed on the printing cylinder bottom cover 42, a No. 3 bevel gear 45 installed on the output shaft of the through motor 41, a No. 4 bevel gear 44 meshing with the No. 3 bevel gear 45, a small shaft 46 fixed in the No. 4 bevel gear 44, a No. 4 connecting rod 47 connected with the small shaft 46, a No. 5 connecting rod 48 hingedly connected with the No. 4 connecting rod 47, a piston 49 hingedly connected with the No. 5 connecting rod 48, an extrusion printing cylinder 43 matched with the piston 49, and a nozzle 50 installed on the extrusion printing cylinder 43.

[0043] The through motor 41 drives the No. 3 bevel gear 45 to operate, the No. 3 bevel gear 45 drives the No. 4 bevel gear 44 and the small shaft 46 to rotate, the small shaft 46 drives the No. 4 connecting rod 47 to move in a circle, the No. 4 connecting rod 47 drives the No. 5 connecting rod 48 to move, the No. 5 connecting rod 48 drives the piston 49 to move linearly, and the piston 49 extrudes the slurry from the nozzle 50 to print.

[0044] Further provided in the application, as shown in Figure 4 and Figure 5As shown, the scanning mechanism 4 includes linear motor modules 17 installed on both sides of the frame, a first connecting plate 18 installed on the linear motor modules 17, a motor fixed long plate 19 installed on the first connecting plate 18, a motor 15 installed on the motor fixed long plate 19, a large straight gear 16 installed on the output shaft of the motor 15, a small gear 20 meshing with the large straight gear 16, a ball screw 21 fixedly connected with the small gear 20, a screw nut sliding block 22 cooperating with the ball screw 21, a two-degree-of-freedom connecting piece 25 and a telescopic support 26 installed on the screw nut sliding block 22, a binocular camera 23 installed on the two-degree-of-freedom connecting piece 25, and a grating projector 24 installed on the telescopic support 26.

[0045] The servo motors of the linear motor modules 17 on both sides drive the ball screw 21 and the screw nut sliding block 22 to move longitudinally, the motor 15 drives the ball screw 21 to rotate, the ball screw 21 drives the screw nut sliding block 22 to complete transverse movement, the screw nut sliding block 22 drives the binocular camera 23 and the grating projector 24 to complete transverse movement, the telescopic support 26 drives the grating projector 24 to move horizontally to adjust the horizontal distance from the binocular camera 23, and the two-degree-of-freedom connecting piece 25 can drive the binocular camera 23 and the grating projector 24 to complete two-degree-of-freedom spatial deflection to adjust the coincidence of the scanning and projection ranges and the scanning dead angle.

[0046] In the above technical solution, first, the scanning mechanism 4 at the middle end of the frame drives the binocular camera 23 and the grating projector 24 to the bone defect site of the patient through the linear motor and the ball screw sliding block 22, then the two-degree-of-freedom connecting piece 25 and the telescopic support 26 complete the arrangement of the position and angle of the binocular camera 23 and the grating projector 24, so that the binocular imaging area and the projection area coincide, and then the binocular stereovision scans the bone defect shape and builds a model. The obtained data is processed by a computer to cut slices and transmit information into the multi-degree-of-freedom suspension movable arm 3, and at the same time, the multi-degree-of-freedom suspension movable arm 3 is also moved to above the bone defect site of the patient by the three-degree-of-freedom motion platform 2, then the multi-degree-of-freedom suspension movable arm 3 drives the extrusion printing device 5 to adjust to a position that can be accurately printed according to the scanned data through the spherical gear joint, and finally the extrusion printing device 5 starts to work, and at the same time, the multi-degree-of-freedom suspension movable arm 3 cooperates with the work of the extrusion printing device 5 in real time until the printing is completed.

[0047] The application provides a 3D printing method suitable for repairing internal bone defects. Figure 8 As shown, the method comprises the following steps:

[0048] 1) The patient with bone defect lies on the above-mentioned operating bed 6, the binocular camera 23 and the grating projector 24 on the scanning mechanism 4 are moved to the position above the patient's bone defect by the two-dimensional planar motion of the linear motor module 17 and the screw-nut slider 22, and then the precise adjustment of the position and posture of the binocular camera 23 and the grating projector 24 is completed by the spatial rotation of the two-degree-of-freedom connecting piece 25 and the telescopic support 26, so that the binocular imaging area and the projection area coincide, the shape of the bone defect is scanned by binocular stereovision, and the obtained data is transmitted to the computer for 3D modeling, and after the analysis and processing of the scanning data by the computer, the three-dimensional model of the shape of the bone defect is established;

[0049] 2) The three-degree-of-freedom motion platform 2 drives the multi-degree-of-freedom suspension movable arm 3 to the position above the target bone defect through xyz axis motion, the three-dimensional model data of the shape of the bone defect established by the scanning mechanism 4 is transmitted into the layering software for layering and slicing processing, and the corresponding code is formed to input the printing device;

[0050] 3) The multi-degree-of-freedom suspension movable arm 3 starts to work according to the code: first, the initial printing height is accurately adjusted by the rotation of the three connecting rods driven by the air cylinder according to the defect position and the model height, then the vertical printing posture is adjusted by the spherical gear joint at the end of the multi-degree-of-freedom suspension movable arm 3 to drive the extrusion printing device 5 to rotate, and then the printing according to the three-dimensional model data starts, first the regular printing is performed, when the internal defect is encountered, the extrusion printing mechanism is rotated to the best printing posture by the spherical joint to print the internal defect, when the extrusion printing needle tube 50 is about to touch the eave of the defect, the multi-degree-of-freedom suspension movable arm 3 is displaced outward from the defect space by the three-degree-of-freedom motion platform 2, then the spherical gear joint at the end of the multi-degree-of-freedom suspension movable arm 3 works to rotate the extrusion printing device 5 by 90 degrees to the horizontal direction, then the connecting rod driven by the air cylinder rotates to lift the extrusion printing device to the required height for horizontal printing, which is just at the position of the structure one layer higher than the previously printed structure, then the three-degree-of-freedom motion platform 2 drives the multi-degree-of-freedom suspension movable arm 3 to drive the printing needle tube 50 of the extrusion printing device 5 to slowly move into the defect space and perform horizontal printing on the basis of the previously printed structure, and then the internal defect is printed and the subsequent regular printing is performed, until the printing is completed.

[0051] In step 3), the slurry is a bio-ink that can be extruded, such as a bio-ink mixed by polyvinyl alcohol and ceramic powder in a certain proportion, or other liquid that can be extruded.

[0052] In actual application, the following embodiments are given in combination with the above-mentioned 3D printing device and printing method Embodiment

[0053] The preparation process of the biomaterials of the present embodiment: To form a three-dimensional biological structure, there are many materials to choose from. Take the three-dimensional structure formed by mixing polyvinyl alcohol and magnesium-doped calcium silicate powder as an example. A 6% (wt) polyvinyl alcohol solution is prepared, and the polyvinyl alcohol solution (5.1 g) and calcium silicate powder (4 g) are uniformly mixed.

[0054] As shown in Figures 1-8 , the repair printing Figure 9 is performed on the bone defect as shown in the figure. The steps are as follows:

[0055] Step 1: The patient with a target bone defect lies on the above-mentioned operating bed cart. The binocular camera and the grating projector on the scanning mechanism are moved by the two-dimensional planar motion of the linear motor module and the screw nut slider to the position above the patient's bone defect, and then the precise adjustment of the position and orientation of the binocular camera and the grating projector is completed by the spatial rotation of the two-degree-of-freedom connecting piece and the telescopic support, so that the binocular imaging area and the projection area coincide. Then the shape of the bone defect is scanned by binocular stereovision, and the obtained data is transmitted to the computer for 3D modeling. After the analysis and processing of the scanning data by the computer, a three-dimensional model of the shape of the bone defect is established. Meanwhile, the three-degree-of-freedom motion platform drives the multi-degree-of-freedom suspension movable arm to the target bone defect through xyz axis motion, and the three-dimensional model data of the shape of the bone defect established by the scanning mechanism is transmitted to the layering software for layering and slicing processing, and the corresponding code is input into the extrusion printing device;

[0056] Step 2: The multi-degree-of-freedom suspension movable arm starts working according to the code: first, the initial printing height is accurately adjusted by the rotation of the three connecting rods driven by the air cylinder according to the defect position and model height, then the multi-degree-of-freedom suspension movable arm works by the spherical gear joint at the end of the arm to drive the extrusion printing device to rotate and adjust to the vertical printing posture, and then the printing according to the divided block areas of the three-dimensional model data is started and a part of the preliminary block printing is completed, as shown in Figure 9 A;

[0057] Step 3: Then the multi-degree-of-freedom suspension movable arm drives the extrusion printing device to move to the next block area (wall surface concave), and the spherical gear drives the extrusion printing device to rotate by a certain angle to achieve the best printing posture, and then the extrusion printing continues, as shown in Figure 9 B;

[0058] Step 4: When the remaining part of the defect is about to contact the extrusion printing device, the multi-degree-of-freedom suspension movable arm drives the extrusion printing device to move outward by a specified distance, the spherical gear drives the extrusion printing device to rotate to the horizontal posture, and then the printing of this part starts, as shown in Figure 9 C;

[0059] Step 5, then multi-degree of freedom suspension active arm drives the extrusion printing device to move to the next area, the spherical gear rotates according to the data again to make the extrusion printing device vertical to the printing area (the best printing position), and printing is performed again, such as Figure 9 D, and the printing is completed. The parts of the 3D printing device for repairing the internal bone defect return to the initial position and stop working.

[0060] The embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the described embodiments. For those skilled in the art, various changes, modifications, replacements and variations of the embodiments including components are made without departing from the principles and spirits of the present application, and still fall within the protection scope of the present application.

Claims

1. A device for on-site 3D printing, characterized in that, The utility model provides a kind of medical three-dimensional printing system, including rack, three degrees of freedom motion platform, multiple degrees of freedom suspension movable arm, extrusion printing mechanism, scanning mechanism and operating bed, the three degrees of freedom motion platform is installed on the top of rack, the multiple degrees of freedom suspension movable arm is installed three degrees of freedom motion platform, the extrusion printing mechanism is installed on multiple degrees of freedom suspension movable arm, the scanning mechanism is installed in the middle end of rack, the rack installs operating bed, the multiple degrees of freedom suspension movable arm includes installation first connecting rod, first cylinder, second connecting rod, second cylinder and third connecting rod, one end of the first connecting rod is fixedly installed on vertical slider, the other end of the first connecting rod is hinged with the top of second connecting rod by hinged piece, the top of first cylinder is fixedly connected to the intermediate position of first connecting rod, the power output end of first cylinder is hinged to the intermediate position of second connecting rod by hinged piece, the top of third connecting rod is with second connecting rod bottom end, the top of second cylinder is fixedly installed on second connecting rod, the power output end of second cylinder is hinged to third connecting rod by hinged piece, the bottom end of third connecting rod is provided with universal connecting piece, the extrusion printing mechanism is installed to the bottom end of third connecting rod by universal connecting piece, the universal connecting piece includes second connecting plate, spherical gear, mounting seat and drive mechanism, one side center of the second connecting plate is fixedly connected to the bottom end of third connecting rod, two mounting seats are symmetrically installed in the middle position of the other side of second connecting plate, spherical gear is installed between two mounting seats, two drive mechanisms are symmetrically arranged on both sides of spherical gear, the drive mechanism includes motor mounting plate fixed on second connecting plate, box fixed seat, the box fixed seat is installed with rotary gear box, the rotary gear box is provided with transmission mechanism, the second motor is installed on the motor mounting plate, the second motor is powered to spherical gear by transmission mechanism, the extrusion printing mechanism is fixedly arranged on the surface of spherical gear.

2. The on-site 3D printing device according to claim 1, characterized in that, The three degrees of freedom motion platform includes longitudinal linear motor module, transverse linear motor module and short vertical short linear module, two longitudinal linear motor modules are arranged in parallel on the top of rack, longitudinal slider is slidably installed on longitudinal linear motor module, transverse linear motor module is fixed on two longitudinal sliders at both ends, transverse linear motor module is slidably installed with transverse slider, short vertical short linear module is fixedly installed on transverse slider, vertical slider is slidably installed on short vertical short linear module, and multiple degrees of freedom suspension movable arm is installed on vertical slider.

3. The on-site 3D printing device according to claim 2, characterized in that, The longitudinal linear motor module includes servo motor, transmission belt and slide rail, the longitudinal slider is slidably installed on the slide rail, the servo motor is arranged on one end of slide rail, the other end of slide rail is provided with roller, the transmission belt is wound on the output shaft of servo motor and roller shaft, the transmission belt is fixedly connected with longitudinal slider, the structure of transverse linear motor module and short vertical short linear module is same with longitudinal linear motor module.

4. The on-site 3D printing device according to claim 3, characterized in that, The scanning mechanism comprises a position adjusting mechanism and an image acquisition unit, the position adjusting mechanism comprises linear modules, a first motor, a large gear, a small gear, a ball screw and a screw nut sliding block, two linear modules are arranged in parallel at the middle part of the rack, the structure of the linear module is same as that of the longitudinal linear motor module, a connecting sliding block is slidably connected to the linear module, first connecting plates are fixedly arranged on the opposite sides of the two connecting sliding blocks, a fixed long plate is horizontally installed between the two first connecting plates, the first motor is installed on the upper surface of the fixed long plate, the ball screw is located below the fixed long plate, and the two ends of the ball screw are rotatably connected to the two first connecting plates through rotary bearings, the large gear is fixedly arranged on the output end of the first motor, the small gear is fixedly installed on the ball screw, the large gear and the small gear are engaged with each other, and the screw nut sliding block is threadedly connected to the ball screw.

5. The on-site 3D printing device according to claim 4, characterized in that, The image acquisition unit comprises a binocular camera and a grating projector, the binocular camera is installed on the screw nut sliding block, the side wall of the screw nut sliding block is provided with a telescopic support, the grating projector is installed on the telescopic support through a two-degree-of-freedom connecting piece, and the grating projector cooperates with the binocular camera.

6. The on-site 3D printing device according to claim 1, characterized in that, The transmission mechanism comprises a single-pole gear, a transition spur gear, a small spur gear, a second bevel gear, a first bevel gear and a rotary bearing, the second bevel gear is fixedly installed on the output end of the second motor, the first bevel gear is installed on the inner wall of the rotary gear box body through a connecting shaft, the first bevel gear and the second bevel gear are engaged with each other, the small spur gear is coaxially arranged with the first bevel gear, the transition spur gear is rotatably installed in the rotary gear box body through a connecting shaft, the small spur gear is engaged with the transition spur gear, the transition spur gear drives the single-pole gear through the rotary bearing, and the single-pole gear is engaged with the spherical gear.

7. A method of in-situ 3D printing, characterized in that, The on-site 3D printing device comprises the following steps: 1) a target bone defect patient lies on the operating bed car, the binocular camera and the grating projector on the scanning mechanism are driven by the linear motor module and the screw nut sliding block to reach above the position of the bone defect of the patient, then the two-degree-of-freedom connecting piece and the telescopic support are used to adjust the position and posture of the binocular camera and the grating projector, so that the binocular imaging area and the projection area coincide, the scanning and imaging are complete, the shape of the bone defect is scanned through binocular stereovision, and the obtained data is transmitted to the computer for 3D modeling, and after the analysis and processing of the scanning data by the computer, a three-dimensional model of the shape of the bone defect is established; 2) the entity data of the model is subjected to layering and slicing processing through layering software, corresponding codes are input into the 3D printing device, and the extrusion printing device is used for real-time printing. 3) the three-dimensional movement of the three degrees of freedom platform drives the multi-degree of freedom suspension movable arm to the position of the patient's bone defect part, and then the three connecting rods of the multi-degree of freedom suspension movable arm are driven by two air cylinders to move relatively to drive the extrusion printing device to a more accurate and suitable pose, and then the extrusion printing device starts to work. The spherical gear part connected with the extrusion printing device can make the extrusion printing device print in multiple directions according to the function of arbitrary angle rotation, which completes the repair printing of the complex bone defect shape.

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