Patent Publication Number: US-2019176371-A1

Title: Three-dimensional printing device and three-dimensional printing method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of China application serial no. 201711313920.9, filed on Dec. 12, 2017. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND 
     Technical Field 
     The disclosure is related to a printing technology, and particularly to a three-dimensional printing device and a three-dimensional printing method. 
     Description of Related Art 
     As the technology advanced in recent years, many methods that utilize additive manufacturing technology (e.g. layer-by-layer model construction) to build three-dimensional (3D) physical models have been proposed. Typically, the additive manufacturing technology is to convert data of a 3D model, which is constructed by software, such as computer aided design (CAD), into multiple thin (quasi-two-dimensional) cross-sectional layers that are stacked in sequence. In the meantime, many techniques for forming thin cross-sectional layers are also proposed. For example, a printing module of a printing apparatus is usually configured to move above a base along an XY plane according to spatial coordinates XYZ constructed according to the design data of the 3D model, so as to use a construction material to form shapes of the cross-sectional shapes correctly. 
     Take the technology that forms 3D objects by curing the construction material with a light source as an example, the printing module is configured to be immersed in a liquid-state modelling material in a tank, and a light source module is disposed on the XY plane to irradiate the liquid-state modelling material which is used as the constructing material, so as to cure and stack the liquid-state modelling material on a printing platform. Accordingly, by moving the printing platform layer-by-layer along the Z axis, the liquid-state modelling material can thus be gradually cured and stacked into a three-dimensional printed object. 
     In existing technologies, when each layer of printed object is cured, at least one of the printing platform and the tank needs to be rotated so that the printed object on the layer can be removed from the tank, and the printing operation of the next layer can be proceeded. However, typically, the removing method is performed by rotating the printing platform or the tank back and forth by 180 degrees, 360 degrees or by a default angle, such that the tank is rotated by the same rotating angle after each layer of printed object is cured. Therefore, the conventional removing method is time-consuming, and it is likely that the printed object is still not removed from the tank after the printing platform or the tank is rotated. In view of the foregoing, a plurality of exemplary embodiments are provided below. 
     SUMMARY 
     The disclosure provides a three-dimensional (3D) printing device and a 3D printing method capable of effectively saving time for performing 3D printing, and effectively separating a completely modeled printed object from a tank. 
     In the disclosure, a 3D printing device includes a controller, a tank and a printing platform. The controller performs 3D printing operation according to a slice file, and judges the magnitude of the shear force corresponding to at least one slice object in the slice file to determine a specific rotating angle. The tank is coupled to the controller. The printing platform is coupled to the controller and disposed above the tank. A carrying surface of the printing platform faces a bottom surface of the tank. When the controller performs the 3D printing operation, the printed object corresponding to the slice object is formed between the carrying surface of the printing platform and the bottom surface of the tank. The controller controls the printing platform to move away the tank by a default vertical distance, and controls the tank to rotate by a specific rotating angle, such that the printed object is removed from the bottom surface of the tank. 
     In the disclosure, a 3D printing method is adapted to a 3D printing device. The 3D printing device includes a controller, a tank and a printing platform. The 3D printing method includes: performing a 3D printing operation according to a slice file by the controller, and judging the magnitude of the shear force corresponding to at least one slice object in the slice file to determine a specific rotating angle; when the controller performs the 3D printing operation, forming the printed object corresponding to the slice object between the carrying surface of the printing platform and the bottom surface of the tank; controlling the printing platform by the controller to move away the tank by a default vertical distance, and controlling the tank to rotate by a specific rotating angle, such that the printed object is removed from the bottom surface of the tank. 
     In summary, the 3D printing device and the 3D printing method of the disclosure are capable of determining a specific rotating angle by judging the magnitude of the shear force corresponding to the slice object in the printing file, thereby effectively saving the time for performing 3D printing as well as effectively separating the completely modeled printed object from the tank. 
     To make the aforementioned more comprehensible, several embodiments accompanied with drawings are described in detail as follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure. 
         FIG. 1  is a schematic view illustrating a three-dimensional (3D) printing device according to an embodiment of the disclosure. 
         FIG. 2A  is a schematic view illustrating forming a printed object according to an embodiment of the disclosure. 
         FIG. 2B  is a schematic view illustrating rotating a tank according to an embodiment of the disclosure. 
         FIG. 2C  is a schematic view illustrating separating a printed object from a tank according to an embodiment of the disclosure. 
         FIG. 3  is a schematic view illustrating analyzing a slice file according to an embodiment of the disclosure. 
         FIG. 4  is a schematic view illustrating analyzing a slice file according to another embodiment of the disclosure. 
         FIG. 5  is a schematic view illustrating analyzing a slice file according to yet another embodiment of the disclosure. 
         FIG. 6  is a flowchart illustrating a 3D printing method according to an embodiment of the disclosure. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In order to facilitate understanding of the content in the disclosure, reference will now be made in detail to the present preferred embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
       FIG. 1  is a schematic view illustrating a three-dimensional (3D) printing device according to an embodiment of the disclosure. Referring to  FIG. 1 , a 3D printing device  100  includes a controller  110 , a tank  120  and a printing platform  130 . The controller  110  is coupled to the tank  120  and the printing platform  130 . In the embodiment, the printing platform  130  is disposed above the tank  120 , and a carrying surface of the printing platform  130  faces the bottom surface of the tank  120 . In the embodiment, when the controller  110  performs 3D printing operation, the printed object corresponding to the slice object is formed between the carrying surface of the printing platform  130  and the bottom surface of the tank  120 . Meanwhile, when the controller  110  performs the 3D printing operation according to the slice file, the controller  110  further judges the magnitude of the shear force corresponding to a slice object in the slice file to determine a specific rotating angle. Therefore, when the controller  110  completes the 3D printing operation of the slice file, the controller  110  controls the printing platform  130  to shift at a default vertical distance in a direction away from the tank  120 , and controls the tank  120  to rotate by the specific rotating angle such that the printed object is removed from the bottom surface of the tank  120 . 
     In the embodiment, the controller  110  may include a processing chip, an image processing chip or, for example, a central processing unit (CPU), or other programmable general purpose or special purpose microprocessor, a digital signal processor (DSP), a programmable logic controller (PCL), an application specific integrated circuit (ASIC), a programmable logic device (PLD), other similar processing circuit or a combination of the above. 
     Additionally, in the embodiment, the 3D printing device  100  may further includes other unit such as a peripheral unit including a motor unit, a roller unit, a sensing unit or the like to be applied to assist in realizing the 3D printing device and the 3D printing method of the disclosure. The motor unit is, for example, configured to rotate the tank  120  or moving the printing platform  130 . However, sufficient teaching, suggestions and implementations regarding the periphery units can be derived by persons skilled in the art according to conventional knowledge of basic unit of typical 3D printing device, and thus no further descriptions are incorporated herein. 
       FIG. 2A  is a schematic view illustrating forming a printed object according to an embodiment of the disclosure. Referring to  FIG. 1  to  FIG. 2A , the 3D printing device  100  may further include a light emitting unit  140 . The light emitting unit  140  is coupled to the controller  110 . In the embodiment, the tank  120  is a transparent material and filled with a liquid-state modeling material. The light emitting unit  140  provides light to irradiate a bottom surface S 2  of the tank  120  so that the liquid-state modeling material in an irradiating region can be cured into a printed object  200 . The liquid-state forming material is, for example, a photosensitive resin material, which should not be construed as a limitation to the disclosure. In the embodiment, the controller  110  controls the light emitting unit  140  to provide the light to irradiate the corresponding position of the bottom surface S 2  of the tank  120  according to the shape of the slice object in the slice file, such that the printed object  200  is formed between the carrying surface S 1  of the printing platform  130  and the bottom surface S 2  of the tank  120 . 
       FIG. 2B  is a schematic view illustrating rotating a tank according to an embodiment of the disclosure. Referring to  FIG. 1  to  FIG. 2B , when the printed object  200  is completely modeled, the controller  110  controls the printing platform  130  to shift at a default vertical distance in a direction (a positive Z-axis direction) away from the tank  120 , and the controller  110  controls the tank  120  to rotate by a specific rotating angle so that the printed object  200  is removed from the bottom surface S 2  of the tank  120 . In the embodiment, the default vertical distance is, for example, 2 mm, which should not be construed as a limitation to the disclosure. 
     Specifically, after the printing platform  130  is shifted at the default vertical distance in the direction (positive Z-axis direction) away from the tank  120 , it is likely that the printed object  200  is still attached to the bottom surface S 2  of the tank  120 . Therefore, the controller  110  further controls the tank  120  to rotate the tank  120 . In the condition that the printing platform  130  is fixed, by rotating the tank, the printed object  200  can be subjected to the shear force to be removed from the bottom surface S 2  of the tank  120 . In the embodiment, the magnitude of the shear force is associated with the size of the area where the printed object  200  is in contact with the printing platform  130  or the position where the printed object  200  is located on the printing platform  130 . In other words, the controller  110  controls the tank  120  to rotate by a specific rotating angle so that the printed object  200  is removed from the bottom surface S 2  of the tank  120 . Moreover, the specific rotating angle is, for example, determined according to the size of the area where the printed object  200  is in contact with the printing platform  130  or the position were the printed object  200  is disposed on the printing platform  130 . In the embodiment, the positive X-axis direction, the positive Y-axis direction and the positive Z-axis direction are perpendicular to each other. A rotating plane of the tank  120  is parallel with a plane formed by the positive X-axis direction and the positive Y-axis direction, and the printing platform  130  is shifted along the positive Z-axis direction. 
     In the embodiment, the controller  110  may control the printing platform  130  to shift at the default vertical distance (2 mm) in a direction (positive Z-axis direction) away from the tank  120  first, and then control the tank  120  to rotate along a specific direction, such that the printed object  200  is removed from the bottom surface S 2  of the tank  120 , which should not be construed as a limitation to the disclosure. In an embodiment, the controller  110  may also control the printing platform  130  to shift at the default vertical distance in a direction (positive Z-axis direction) away from the tank  120  while simultaneously controlling the tank  120  to rotate along a specific direction, such that the printed object  200  is removed from the bottom surface S 2  of the tank  120 . 
     In the embodiment, the controller  110  controls the tank  120  to rotate by a specific rotating angle in a specific rotating direction so that the printed object  200  is removed from the bottom surface S 2  of the tank  120 . It should be indicated that the controller  110  in the embodiment does not rotate the tank  120  by the specific rotating angle again in a direction opposite to the specific rotating direction. In the embodiment, since the printing platform  130  is fixed, no matter which angle by which the tank  120  is rotated, the position on which the printed object  200  is fixed on the printing platform  130  is not affected. However, in an embodiment, in consideration that if the bottom surface S 2  of the tank  120  might not be parallel with the horizontal plane, after the tank  120  is rotated, when the next layer of printed object is formed between the printing platform  130  and the tank  120 , the next layer of printed object is likely to be inclined. Therefore, in specific condition, in order to achieve printing accuracy, when the controller  110  controls the tank  120  to rotate by a specific rotating angle in a specific rotating direction, the controller  110  may further control the tank  120  to rotate by the specific rotating angle again in a direction opposite to the specific rotating direction, such that the tank  120  is restored to the same position. 
       FIG. 2C  is a schematic view illustrating separating a printed object from a tank according to an embodiment of the disclosure. Referring to  FIG. 1  to  FIG. 2C , the controller  110  controls the printing platform  130  to shift at another default vertical distance in a direction (positive Z-axis direction) away from the tank  120 , such that a gap is provided between the printed object  200  and the bottom surface S 2  of the tank  120  to cure the next layer of printed object. Therefore, the height of the gap may be a default height for the next layer of printed object. Also, in the embodiment, the controller  110  may proceed to analyze the next layer of slice file to judge the magnitude of another shear force corresponding to the next layer of slice object in the next layer of slice file to determine another specific rotating angle. In other words, in the printing process of a multiple-layer printed object, after each layer of printed object is formed, since it is required that the tank  120  be rotated by a specific rotating angle to separate the newly modeled printed object from the bottom surface of the tank  120  in order to perform the next modeling printing, for the 3D printing device  100  in the embodiment, in the printing process of the multiple-layer printed object, there is no need to cost additional time for the tank  120  to be rotated additionally. The specific rotating angle by which the tank  120  corresponding to each layer of printed object is separately determined according to the analyzing result of the corresponding slice file. 
       FIG. 3  is a schematic view illustrating analyzing a slice file according to an embodiment of the disclosure. Referring to  FIG. 1  and  FIG. 3 , the slice file may include a layered image  300  shown in  FIG. 3 . In the embodiment, the layered image  300  may include a plurality of slice objects  301 ,  302 ,  303 . The slice objects  301 ,  302  and  303  have different shapes and sizes. In the embodiment, a platform range  330  corresponds to a carrying surface range (e.g., a range of carrying surface S 1  shown in  FIG. 2A ) of the printing platform  130 . The slice objects  301 ,  302  and  303  are distributed in the platform range  330  at different positions. In the embodiment, the controller  110  determines the specific rotating angle of the tank  120  according to the largest area of one of the slice objects  301 ,  302  and  303 , and the specific rotating angle of the tank  120  is proportional to the largest area of one of the laired objects  301 ,  302  and  303 . 
     Specifically, the controller  110  may analyze the size of the area of respective slice objects  301 ,  302  and  303  of the layered image  300 , and determine that the slice object  301  has the largest area. The controller  110  may further determine the magnitude of the corresponding shear force according to the area of the slice object  301 . After calculating the shear force corresponding to the area of the slice object  301 , the controller  110  can acquire the specific rotating angle corresponding to the tank  120 . Therefore, when the controller  110  completes printing the plurality of printed objects corresponding to the slice objects  301 ,  302  and  303  according to the layered image  300 , the controller  110  can rotate the tank  120  by the acquired specific rotating angle of the tank  120  such that the printed objects can be effectively removed from the bottom surface of the tank  120 , and the 3D printing operation for the next layer can be performed. 
     Additionally, sufficient teaching, suggestions and implementation regarding the calculating method of the magnitude of the shear force can be derived by persons skilled in the art according to the material characteristics of the printed object, the surface material characteristic of the tank and general mechanics calculation, and thus no further descriptions are incorporated herein. 
     However, in an embodiment, the controller  110  may determine the specific rotating angle according to a total area of the slice objects  301 ,  302  and  303 , and the specific rotating angle is proportional to the total area. Specifically, the controller  110  may analyze the size of the total area of the slice objects  301 ,  302  and  303  of the layered image  300 . The controller  110  may further determine the magnitude of the corresponding shear force according to the total area of the slice objects  301 ,  302  and  303 . After calculating the magnitude of the shear force corresponding to the total area of the slice objects  301 ,  302  and  303 , the controllers  110  can obtain the specific rotating angle corresponding to the tank  120 . Therefore, when the controller  110  completes printing the plurality of printed objects corresponding to the slice objects  301 ,  302  and  303  according to the layered image  300 , the controller  110  can make the printed objects to be effectively removed from the bottom surface of the tank  120  by rotating the tank  120  at the acquired specific rotating angle of the tank  120 , so that the 3D printing operation for the next layer can be performed. 
       FIG. 4  is a schematic view illustrating analyzing a slice file according to another embodiment of the disclosure. Referring to  FIG. 1  and  FIG. 4 , the slice file may include a layered image  400  shown in  FIG. 4 . In the embodiment, the layered image  400  may include a plurality of slice objects  401 ,  402  and  403 . The slice objects  401 ,  402  and  403  have different shapes and sizes. In the embodiment, a platform range  430  corresponds to the carrying surface range (e.g., the range of the carrying surface S 1  shown in  FIG. 2A ) of the printing platform  130 . The slice objects  401 ,  402  and  403  are distributed in the platform range  430  at different positions. In the embodiment, the platform range  430  may be further divided into a plurality of areas  431 ,  432  and  433  from outside to inside. The controller  110  determines the specific rotating angle according to one of the areas  431 ,  432  and  433 , and the specific rotating angle is proportional to a horizontal distance between one of the areas  431 ,  432  and  433  and a central point C of the platform range  430 . 
     Specifically, the controller  110  may analyze the position of the slice objects  401 ,  402  and  403  of the layered image  400  in the layered image  400 . The slice objects  401 ,  402  and  403  are respectively located in the areas  431 ,  432  and  433 . Moreover, one of the slice objects  401 ,  402  and  403  is located at a position in one of the areas  431 ,  432  and  433  farthest from the central point C of the platform range  430 . In the embodiment, the controller  110  judges that the position of the slice object  401  is farthest from the central point C of the platform range  430 . Thus, the controller  110  determines the corresponding specific rotating angle according to the area  431  in which the slice object  401  is located. It should be pointed out that, if farther away from the central point C of the platform range  430 , the specific rotating angle is larger. Therefore, when the controller  110  completes printing a plurality of printed objects corresponding to the slice objects  401 ,  402  and  403  according to the layered image  400 , the controller  110  can rotate the tank  120  by the required specific rotating angle of the tank  120 , such that the printed objects can be effectively removed from the bottom surface of the tank  120 , and the 3D printing operation for the next layer can be performed. 
     However, in an embodiment, the controller  110  may directly analyze a horizontal distance D 1 , D 2  and D 3  between the slice objects  401 ,  402  and  403  and the central point C of the platform range  430 . Also, the controller  110  may pre-establish a lookup table to directly obtain the corresponding specific rotating angle by looking up the table. 
       FIG. 5  is a schematic view illustrating analyzing a slice file according to yet another embodiment of the disclosure. Referring to  FIG. 1  and  FIG. 5 , the slice file may include a layered image  500  shown in  FIG. 5 . In the embodiment, the layered image  500  may include a plurality of slice objects  501 ,  502  and  503 . The slice objects  501 ,  502  and  503  have different shapes and sizes. In the embodiment, a platform range  530  corresponds to the carrying surface range (e.g., the range of the carrying surface S 1  shown in  FIG. 2A ) of the printing platform  530 . The slice objects  501 ,  502  and  503  are distributed in the platform range  530  at different positions. In the embodiment, the controller  110  determines the corresponding arc length according to one of the slice objects  501 ,  502  and  503  having the largest width distance, and calculate the specific rotating angle according to the arc length, wherein the specific rotating angle is proportional to the largest width distance. 
     Specifically, the controller  110  may analyze the width distance L 1 , L 2  and L 3  of respective slice objects  501 ,  502  and  503  of the layered image  500 , and determine that the slice object  501  has the largest width distance. The controller  110  may further determine the corresponding arc length according to the width distance L 1  of the slice object  501 . After calculating the arc length corresponding to the width distance L 1  of the slice object  501 , the controller  110  can obtain the specific rotating angle corresponding to the tank  120 . Therefore, when the controller  110  completes printing the plurality of printed objects corresponding to the slice objects  501 ,  502  and  503  according to the layered image  500 , the controller  110  can rotate the tank  120  by the acquired specific rotating angle of the tank  120 , such that the printed objects can be effectively removed from the bottom surface of the tank  120 , and the 3D printing operation for the next layer can be performed. 
     In the embodiment, the arc length refers to the distance at which the position corresponding to the printed objects on the carrying surface of the printing platform  130  is shifted when the printing platform  130  is rotated. In the embodiment, the controller  110  uses the largest width distance of the slice objects  501 ,  502  and  503  as the corresponding arc length. In other words, in order to enable the printed objects corresponding to the slice objects  501 ,  502  and  503  to be smoothly removed from the bottom surface of the tank  120 , the tank  120  is at least rotated by a specific rotating angle corresponding to the largest width distance. In the embodiment, the conversion between the arc length and the specific rotating angle may be expressed via the following equation (1): 
     
       
         
           
             
               
                 
                   L 
                   = 
                   
                     θ 
                     × 
                     
                       
                         ( 
                         
                           2 
                            
                           r 
                           × 
                           π 
                         
                         ) 
                       
                       360 
                     
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     In the above equation (1), L represents arc length, θ represents rotating angle, r represents the horizontal distance (or rotating radius) between the central point C of the printing range  530  to a specific position. For example, the controller  110  uses the width distance L 1  as the arc length L, and uses the horizontal distance between the center of the slice object  501  to the central point C of the printing range  530  as r. Therefore, after calculation, the controller  110  can acquire the corresponding rotating angle θ. 
       FIG. 6  is a flowchart illustrating a 3D printing method according to an embodiment of the disclosure. Referring to  FIG. 1  to  FIG. 2C  and  FIG. 6 . The 3D printing method in the embodiment may at least be adapted to the 3D printing device  100  in the embodiments illustrated in  FIG. 1  to  FIG. 2C . In step S 610 , the 3D printing operation is performed by the controller  110  according to the slice file, and the magnitude of shear force corresponding to the slice object in the slice file is judged to determine the specific rotating angle. In step S 620 , when the controller  110  performs the 3D printing operation, the printed object  200  corresponding to the slice object is formed between the carrying surface S 1  of the printing platform  130  and the bottom surface S 2  of the tank  120 . In step S 630 , the printing platform  130  is controlled by the controller  100  to shift at the default vertical distance in the direction away from the tank  120 , and the tank  120  is controlled by the controller  100  to rotate by the determined specific rotating angle, such that the printed object  200  is removed from the bottom surface S 2  of the tank  120 . Therefore, the 3D printing method in the embodiment can effectively remove the completely modeled printed object  200  from the tank  120 , so that the printing operation for the next layer of printed object can be performed. Also, the 3D printing method in the embodiment can effectively save the time for printing multiple-layer printed object. 
     In summary, the 3D printing device and the 3D printing method of the disclosure are capable of judging the magnitude of the shear force corresponding to the slice object in the printing file to determine the specific rotating angle, such that the tank can be rotated by the specific rotating angle after the printed object corresponding to the slice object is completely printed, thereby ensuring that the printed object can be practically separated from the tank without costing additional rotating time. Therefore, the 3D printing device and the 3D printing method of the disclosure can bring the effect of effectively saving time for 3D printing, and have the function of effectively separating the modeled printed object from the tank. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided that they fall within the scope of the following claims and their equivalents.