A linear light source based 3D printing forming method and device

Abstract

The present application relates to the technical field of 3D printing, and particularly relates to a 3D printing forming method and device based on linear light source, which comprises the following steps: establishing a three-dimensional coordinate system according to the geometric information of a 3D printing device; obtaining a triangular mesh model of a three-dimensional model according to a model file of the three-dimensional model to be printed; projecting all vertices in the triangular mesh model onto a YOZ plane in the three-dimensional coordinate system to obtain a projection polygon; performing curved surface slice segmentation on the projection polygon; calculating a sampling interval of a filling sampling straight line in an i-th layer curved surface slice, calculating a sampling angle step of the filling sampling straight line in the sampling interval according to the projection width of the linear light source, and obtaining a filling scanning line segment intersected by the sampling straight line and the triangular mesh model in the i-th layer curved surface slice according to the sampling angle step; and printing the three-dimensional model layer by layer according to the filling scanning line segment, thereby improving the printing efficiency of the three-dimensional model.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular to a 3D printing method and apparatus based on a linear light source. Background Technology

[0002] 3D printing technology, also known as additive manufacturing technology, is an emerging manufacturing technology that uses digital models as a basis to build up materials layer by layer to create a physical object. The consumables used in stereolithography 3D printing are generally liquid photosensitive resins (also known as photocurable resins, photosensitive resins, etc.). Photosensitive resins are colloidal substances composed of polymers that undergo a transformation from liquid to solid state under the stimulation of light such as ultraviolet light of a certain wavelength. Photosensitive resins have advantages such as low viscosity, small curing shrinkage, fast curing rate, small swelling, high photosensitivity, and high degree of curing, and are therefore widely used in stereolithography 3D printing processes.

[0003] Based on the structural characteristics of 3D printing equipment, stereolithography can be further subdivided into stereolithography appearance (SLA), direct light processing (DLP), and liquid crystal display (LCD) processes. SLA uses an ultraviolet (UV) laser as the point light source for scanning and printing. A galvanometer module controls the UV laser beam to scan and print from point to line and line to surface on the printing plane. Because SLA uses a point-to-point scanning method, and after each layer is scanned and printed, a scraper structure needs to be moved back and forth to level the liquid resin before the next layer can be scanned and printed, significantly reducing the forming efficiency of SLA. Furthermore, the UV laser and galvanometer used in SLA also significantly increase the cost of the equipment.

[0004] The DLP process uses an ultraviolet (UV) projector as its light source. It employs a high-resolution micromirror array to create a mask pattern for each printing layer. This pattern information is projected layer by layer to solidify the liquid photosensitive resin, thus completing the 3D model printing. However, the forming accuracy of the DLP process depends on the resolution of the micromirror array, and a high-resolution, large-format micromirror array increases the cost of DLP equipment. Generally, DLP equipment moves the formed model after each layer exposure in two ways: one is to raise the current forming layer by one layer thickness, requiring the DLP projection light to pass through a high-transparency glass layer from bottom to top onto the liquid photosensitive resin at the bottom. However, this method causes wear on the glass surface of the bottom layer over long-term use, affecting the subsequent forming quality; the other is to lower the current forming layer by one layer thickness, then a scraper structure needs to move back and forth to level the liquid resin before the next layer can be printed. However, this method significantly reduces the forming efficiency of the DLP process.

[0005] The LCD process is similar in principle to DLP technology, but it does not use UV projectors and micromirror arrays to generate projected cross-sectional patterns. Instead, it generates specific cross-sectional patterns by deflecting inexpensive LCD liquid crystals. However, the light power in LCD is significantly lower than that in DLP UV light. This requires LCD equipment to increase the exposure time of each layer to improve the curing strength of the liquid resin, resulting in lower printing efficiency for the LCD process. In summary, current mainstream 3D printing technologies suffer from an inability to effectively balance forming efficiency, forming accuracy, and equipment cost. Summary of the Invention

[0006] Therefore, it is necessary to provide a 3D printing method and apparatus based on a linear light source to address the aforementioned technical problems, in order to solve the problem that existing 3D printing methods and apparatus cannot effectively balance forming efficiency, forming accuracy and equipment cost.

[0007] In a first aspect, embodiments of the present invention provide a 3D printing method based on a linear light source, the method comprising the following steps:

[0008] S100: Obtain the geometric information of the 3D printing device, which includes a rotating base, a movable scraper, a material hopper, and a linear light source. Based on the geometric information of the 3D printing device, establish a three-dimensional coordinate system with the central axis of the rotating base as the X-axis.

[0009] S200: Obtain the model file of the 3D model to be printed, and perform topological reconstruction on the vertex coordinate relationship of the model in the model file to obtain the triangular mesh model of the 3D model;

[0010] S300: Project all vertices of the triangular mesh model onto the YOZ plane in the three-dimensional coordinate system to obtain the projected polygon of the triangular mesh model on the YOZ plane;

[0011] S400: Using the projection point of the central axis of the rotating base on the YOZ plane as the center, the projected polygon is divided into several layers of surface slices by surface slicing.

[0012] S500: Based on the projected polygon and the origin position of the three-dimensional coordinate system, calculate the sampling interval of the line to be filled in the i-th layer surface slice; based on the projection width of the linear light source on the YOZ plane, calculate the sampling angle step size of the line to be filled in the sampling interval; based on the sampling angle step size, calculate the angle distribution corresponding to the line to be filled in the i-th layer surface slice.

[0013] S600: Based on the angle distribution, find the filling scan line segment where the sampling line to be filled in the i-th layer curved surface intersects with the triangular mesh model;

[0014] S700: Generate a linear light source mask for the i-th layer based on the filled scan line segment, and print the i-th layer based on the linear light source mask.

[0015] The advantages of this invention compared to the prior art are as follows:

[0016] The present invention discloses a 3D printing method based on a linear light source. A three-dimensional coordinate system is established using a 3D printing device. All vertices of the triangular mesh model are projected onto the YOZ plane of the three-dimensional coordinate system. Then, surface slicing is performed to form several layers of surface slices. The sampling intervals for filling sampling lines in each layer of surface slice are determined, as well as the filling scan segments where these sampling intervals intersect with the triangular mesh model. The three-dimensional model is then printed layer by layer based on these filling scan segments. This method linearly plans the pattern to be printed in each layer of the three-dimensional model, enabling high-precision generation of linear scanning paths for complex three-dimensional models and improving the printing efficiency of the three-dimensional model.

[0017] Optional, the S400 includes:

[0018] Calculate the maximum distance from all projection points in the projected polygon to the origin of the three-dimensional coordinate system, where the origin of the three-dimensional coordinate system is the projection point of the central axis of the rotating platform onto the YOZ plane;

[0019] Based on the maximum distance, the radius of the rotating platform, and the preset thickness of each surface slice, the radius of each surface slice is calculated, and the projected polygon is segmented into surface slices according to the radius of each surface slice.

[0020] Optionally, based on the projected polygon and the origin position of the three-dimensional coordinate system, the sampling interval of the lines to be filled in the i-th layer of the surface slice is calculated, including:

[0021] Based on the radius Ri corresponding to the i-th layer surface slice, calculate the intersection point of the projected polygon and the circle containing the surface slice with radius Ri, connect the intersection points, and obtain the sampling interval of the line to be filled.

[0022] Optionally, based on the projection width of the linear light source on the YOZ plane, the sampling angle step size for filling the sampling line in the sampling interval is calculated, including:

[0023] Connect the origin of the three-dimensional coordinate system with two intersection points in each set of intersection points to obtain the first straight line and the second straight line that intersect the Y-axis. Calculate the angle θmax between the first straight line and the positive Y-axis and the angle θmin between the second straight line and the positive Y-axis.

[0024] Based on the projection width of the linear light source on the YOZ plane, the included angle θmax, and the included angle θmin, calculate the sampling angle step size of the line to be filled in the arc where the projected polygon intersects with the circle containing the radius Ri.

[0025] Optionally, based on the angle distribution, the filled scan line segment intersecting the sampling line in the i-th layer surface section and the triangular mesh model is obtained, including:

[0026] Calculate the coordinates of the projection point of the sampling line in the YOZ plane based on the angular distribution;

[0027] Traverse all the triangular faces of the triangular mesh model and their projection triangles in the YOZ plane. If the projection triangle covers the coordinates of the projection point, use the method of calculating the intersection of the three-dimensional line and the triangular face to calculate the three-dimensional coordinates of the intersection of the sampling line and the triangular mesh model.

[0028] The three-dimensional coordinates of all the obtained intersection points are sorted in ascending order according to the X-axis component to obtain an ordered sequence of intersection points between the sampling line and the triangular patch model;

[0029] According to the ordered intersection sequence, all intersections are grouped into pairs, and the two intersections in each group form a filled scan line segment.

[0030] Optionally, generating a linear light source mask for the i-th layer based on the filled scan line segment, and printing the i-th layer based on the linear light source mask, includes:

[0031] Move the movable scraper to a position where the distance between it and the i-th layer of curved surface slice is the preset thickness of each layer of curved surface slice;

[0032] Set the surface linear velocity of the i-th layer surface slice to V, calculate the angular velocity ωi of the uniform rotation of the rotating platform based on the radius Ri of the circle containing the i-th layer surface slice, and control the rotating platform to rotate at a uniform speed based on the angular velocity ωi.

[0033] The i-th layer is printed by irradiating the printing material corresponding to the i-th layer with the linear light source and the linear light source mask.

[0034] Secondly, embodiments of the present invention provide a 3D printing forming apparatus based on a linear light source, the apparatus comprising:

[0035] The system includes a rotating base, a movable scraper, a consumable material container, and a linear light source. The rotating base is arranged parallel to the consumable material container above it and extends into the consumable material container by a preset distance, so that the surface of the rotating base contacts the printing consumable material in the consumable material container.

[0036] The movable scraper is arranged parallel to the central axis of the rotating base and is spaced at a preset distance from the surface of the rotating base;

[0037] The linear light source is positioned above the rotating platform, and is parallel to the central axis of the rotating platform and spaced at a predetermined distance from the surface of the rotating platform.

[0038] The 3D printing apparatus further includes: a controller, a memory, and a 3D printing program stored in the memory and executable on the controller. When the controller executes the 3D printing program, it implements the 3D printing method based on a linear light source as described in the first aspect, so as to control the rotating platform, the moving scraper, and the linear light source to print the three-dimensional model.

[0039] The advantages of this invention compared to the prior art are as follows:

[0040] The 3D printing forming device based on linear light source of the present invention sets a rotating base above the consumable material bin, and adjusts the thickness of each layer of printing consumable by moving the scraper. During the rotation of the rotating base, the linear light source generates scanning light pattern in real time. The scraper does not need to be moved repeatedly during the printing process, thereby improving printing efficiency. Moreover, the device has a simple structure and low manufacturing cost.

[0041] Optionally, the linear light source includes an ultraviolet lamp and a linear lens, wherein the linear lens is used to generate an illumination pattern of the linear light source from the ultraviolet light emitted by the ultraviolet lamp according to the 3D printing method.

[0042] Optionally, the 3D printing forming apparatus further includes: a horizontal slide rail, in which the movable scraper is mounted, so that the movable scraper can move horizontally via the horizontal slide rail.

[0043] Optionally, the 3D printing forming apparatus further includes a vertical slide rail, in which the linear light source is mounted, so that the linear light source can move vertically through the vertical slide rail. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic flowchart of a 3D printing forming method based on a linear light source provided in one embodiment of the present invention;

[0046] Figure 2 This is a two-dimensional planar schematic diagram of a 3D printing forming device based on a linear light source provided in one embodiment of the present invention;

[0047] Figure 3 This is a three-dimensional schematic diagram of a 3D printing forming device based on a linear light source provided in one embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of a curved surface slice provided in one embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of calculating the angle corresponding to the sampling line of a surface slice according to an embodiment of the present invention;

[0050] Figure 6 This is a schematic diagram of a mask linear optical path provided in one embodiment of the present invention. Detailed Implementation

[0051] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of the invention with unnecessary detail.

[0052] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0053] It should also be understood that the term “and / or” as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0054] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0055] Furthermore, in the description of this invention and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0056] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of the invention include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0057] It should be understood that the sequence number of each step in the following embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0058] In one embodiment, a method such as Figure 1 The illustrated 3D printing method based on a linear light source may include the following steps:

[0059] Step S100: Obtain the geometric information of the 3D printing device, which includes a rotating base, a movable scraper, a material hopper, and a linear light source. Based on the geometric information of the 3D printing device, establish a three-dimensional coordinate system with the central axis of the rotating base as the X-axis.

[0060] See Figure 2 This is a two-dimensional planar schematic diagram of a 3D printing forming device provided in this embodiment. See also... Figure 3 This is a three-dimensional schematic diagram of a 3D printing forming device provided in this embodiment. Figure 2 and Figure 3 It is known that the printing device includes: a linear light source 1, a rotating base 2, a movable scraper 3, a consumable material tank 4, a horizontal slide rail 6, and a vertical slide rail 7; wherein, the rotating base 2 adopts a cylindrical structure as the printing base, and the cylindrical base can rotate at a uniform speed; the consumable material tank 4 is located below the rotating base 2, and is filled with liquid printing consumable material 5, which is a photosensitive resin material, to ensure that the lower half of the rotating base 2 can be immersed in the liquid photosensitive resin material.

[0061] The movable scraper 3 is mounted on the horizontal slide rail 6 and can move horizontally under program control. When the rotating base 2 rotates at a constant speed, the rotating base 2, which is immersed in liquid photosensitive resin material, will adhere to the liquid photosensitive resin material; the linear light source 1 is mounted on the vertical slide rail 7 and can move vertically under program control.

[0062] Based on the geometric information of the printing device, a three-dimensional coordinate system is established with the central axis of the rotating base 2 as the X-axis. In addition to the X-axis, the three-dimensional coordinate system also includes the Y-axis and Z-axis. The YOZ plane formed by the Y-axis and Z-axis is perpendicular to the X-axis.

[0063] Step S200: Obtain the model file of the 3D model to be printed, and perform topological reconstruction on the vertex coordinate relationship of the model in the model file to obtain the triangular mesh model of the 3D model.

[0064] In this embodiment, a 3D model to be printed can be created using 3D modeling software. The created 3D model can be exported as a 3D model in STL file format. Based on the coordinate relationship of the model vertices in the STL file, the triangular mesh model G of the 3D model can be obtained through topological reconstruction, and the adjacency topological relationship structure between the triangular faces in the triangular mesh model G can be established.

[0065] The method of obtaining the corresponding triangular mesh model from the 3D model is an existing technology and will not be elaborated here.

[0066] Step S300: Project all vertices of the triangular mesh model onto the YOZ plane in the three-dimensional coordinate system to obtain the projected polygon of the triangular mesh model on the YOZ plane.

[0067] See Figure 4 Projecting all vertices of the triangular mesh model G established above onto the YOZ plane of the three-dimensional coordinate system, we obtain the projection polygon 11 of the triangular mesh model G on the YOZ plane. This projection polygon 11 represents the outer boundary contour formed by the vertical projection of the triangular mesh model G onto the YOZ plane.

[0068] Step S400: Using the projection point of the central axis of the rotating base on the YOZ plane as the center, the projected polygon is divided into curved surface slices to obtain several layers of curved surface slices.

[0069] Based on the projected polygon 11, calculate the radius of the different layers of the surface slices required for the 3D model to be printed. The specific steps are as follows:

[0070] Step S401: As Figure 4 As shown, first calculate the maximum distance from all projection points in the projection polygon 11 to the center point 13 of the rotating platform. This maximum distance value is the maximum surface slice radius Rmax for surface slicing.

[0071] Step S402: Obtain the radius of the projected profile 14 of the rotating base as R0, and set the layer thickness of each surface slice as h. Then, the radius of the surface slice profile 12 where different surface slice layers are located can be calculated using the formula Ri=R0+i*h, where i is used to represent the index of the surface slice layer, and 1≤i≤Imax, Imax is the index value of the largest surface slice layer in the model, and Imax=(Rmax-R0) / h.

[0072] Step S500: Based on the projected polygon and the origin position of the three-dimensional coordinate system, calculate the sampling interval of the line to be filled in the i-th layer surface slice; based on the projection width of the linear light source on the YOZ plane, calculate the sampling angle step size of the line to be filled in the sampling interval; based on the sampling angle step size, calculate the angle distribution corresponding to the line to be filled in the i-th layer surface slice.

[0073] See Figure 5 Based on the projected polygon 11, calculate the corresponding angle distribution θj of the lines that need to be filled in the different surface slice layer thicknesses, and save them into the sequence W[i][j], where i represents the layer thickness index of the current surface slice, and θj represents the angle value corresponding to the j-th line that needs to be filled in the current surface slice layer thickness. The specific steps are as follows:

[0074] Step S501: Based on the radius Ri corresponding to the current surface slice layer thickness, calculate the sequence of intersection points between the projected polygon and the circle containing the radius Ri. These intersection point sequences are grouped in pairs, and the arc formed by the two intersection points in each group is the sampling interval where the fill line needs to be added. For example, if the intersection points are P1 and P2, then the arc formed by the intersection points of P1 and P2 is the sampling interval where the fill line needs to be added.

[0075] Step S502: Connect the center of the circle with the intersection points P1 and P2 respectively to obtain the lines OP1 and OP2. Calculate the angle θmax between line OP1 and the positive Y-axis, and the angle θmin between line OP2 and the positive Y-axis.

[0076] Step S503: Obtain the actual width w of the linear light source projection and set w as the interval between the sampling lines to be filled; calculate the sampling angle step size of the lines to be filled in the current arc P1P2 according to the formula ε=(w / Ri)*180 / 2π, where ε is the sampling angle step size and Ri is the radius of the i-th layer surface slice.

[0077] Step S504: Based on the sampling angle step size ε, the angle θj that needs to be filled by the sampling line in the arc P1P2 can be calculated as θj = θmin + ε*j, where 0 ≤ j ≤ Jmax, Jmax is the number of samplings corresponding to the maximum angle value, and Jmax = (θmax - θmin) / ε. The angle θj corresponding to the filling sampling line in the current surface slice is saved to the sequence W[i][j].

[0078] Step S600: Based on the angle distribution, determine the filling scan line segment where the sampling line to be filled in the i-th layer surface intersects with the triangular mesh model.

[0079] See Figure 6 Based on the sequence W[i][j] calculated in step S504, each slice layer and the ordered intersection sequence of each filling linear line 17 in the corresponding slice layer with the boundary 16 of the triangular mesh model G are processed sequentially. These intersection points are then grouped in pairs, and the two intersection points in each group form a filling scan line segment. The set of filling scan line segments formed by the final intersection sequence is saved in the sequence W[i][j]. This set of filling scan line segments is the scan line segment at the current surface slice position at the sampling line position. For example, when the ordered intersection sequence only includes points P3 and P4, points P3 and P4 are connected to form the filling scan line segment 18.

[0080] In this embodiment, the steps for calculating the ordered sequence of intersection points between the sampling line and the boundary of the triangular mesh model G are as follows:

[0081] Step S601: Assuming the angle corresponding to the current filling sampling line is θj, the coordinates of the projection point of this sampling line on the YOZ plane are Ps = (y, z):

[0082]

[0083] Step S602: Traverse the projection triangles of each triangular facet of the triangular mesh model G in the YOZ plane. If the projection triangle corresponding to a certain triangular facet covers the projection point Ps, calculate the intersection point of the currently filled sampling line and the triangular facet. Thus, this invention can calculate the three-dimensional coordinates of all intersection points with the triangular mesh model G.

[0084] Those skilled in the art will recognize that the process of calculating the intersection of a straight line and a triangular facet in three-dimensional space is existing technology and will not be described in detail here.

[0085] Step S603: Sort all the obtained intersection points in ascending order according to the x-component to obtain the ordered intersection point sequence of the sampling line and the triangular patch model G. Group the ordered intersection point sequence into pairs, and the two intersection points in each group form a filled scan line segment.

[0086] Step S700: Generate a linear light source mask for the i-th layer based on the filled scan line segment, and print the i-th layer based on the linear light source mask.

[0087] In this embodiment, during the 3D printing process based on a linear light source, as the rotating platform is printed layer by layer, the radius Ri of the forming surface of the rotating platform gradually increases. During the rotation of the rotating platform, assuming that the linear velocity of the forming surface of the rotating platform is V, the linear ultraviolet light source can effectively cure the photosensitive resin material on the forming surface of the rotating platform. That is, during the entire printing process, it is necessary to ensure that the linear velocity V of the forming surface of the rotating platform is a constant value.

[0088] The specific 3D printing process includes the following steps:

[0089] Step S701: During the initialization phase of printing, the linear light source is moved downwards to a suitable height m from the forming surface of the rotating base. This height m can be determined through multiple trials to find the optimal value. Then, the squeegee is moved to the position of the horizontal track, see [link to previous steps]. Figure 2 This ensures that the distance between the rotating base and the forming surface reaches the set curved surface forming thickness value h.

[0090] Step S702: Based on the sequence W[i][j] calculated in step S504, the printing process for each surface includes the following steps:

[0091] Step S7021: Assuming the index of the currently formed surface is i (1≤i≤Imax), the radius Ri of the current surface formation can be obtained, and the angular velocity ωi=V / Ri of the rotating platform during the current surface formation process can be calculated.

[0092] Step S7022: Obtain the angle distribution result θj (0≤j≤Jmax) of the current surface layer that needs to be scanned by the linear light source from the sequence W[i][j], and print the current surface layer. During this process, the rotating platform always maintains an angular velocity ωi and rotates at a constant speed.

[0093] If the forming base in the current curved surface forming layer has rotated to a position of θj, then the set of filling scan segments at the current angular position is taken out from the sequence W[i][j], and a mask for a linear scanning light source is formed based on this data (the subsequent linear light source can cure the photosensitive resin material corresponding to the filling scan segments after irradiating the photosensitive resin material through the mask). A linear scan is performed on the surface of the rotating base at the current angular position, and the photosensitive resin material is cured on the surface of the previously formed curved surface material.

[0094] Continue shaping the next linear scan angle (j+1) of the current surface layer until j = Jmax, then complete all linear scan tasks at the current surface radius position.

[0095] S7023: Move the linear light source upward by the height of the curved surface forming layer thickness h, and at the same time move the moving scraper horizontally backward by the distance of the layer thickness h.

[0096] Step S703: Repeat step S702 above to continue printing the next surface (i+1) until i = Imax, then the surface printing and forming of the entire three-dimensional mesh model G is completed.

[0097] The 3D printing method based on a linear light source in this embodiment has the following characteristics:

[0098] (1) The method first models the three-dimensional model to be printed and converts it into a triangular mesh model. Then, it performs precise surface slicing on the triangular mesh model and generates linear fill scan line segment data for different surface forming and different rotation angle positions. Different forming surfaces are formed at different rotation angle positions on the rotating base of the 3D printing device. These linear fill scan line data are used to generate strip light with different patterns, so that linear scan printing is completed at the current forming position of the rotating base. This method can handle complex mesh models and generate linear scan path data with high precision.

[0099] (2) The rotating base is always rotating during the forming process and uses a linear light source as a feature of stereolithography. Therefore, it has high forming efficiency and forming accuracy, overcoming the low efficiency problem of traditional SLA and other processes that rely on the reciprocating motion of the scraper and point light source scanning point by point. At the same time, compared with DLP and LCD processes, this method has the advantages of large forming area, high forming efficiency, good forming quality and low cost.

[0100] In one embodiment, a method such as Figure 2 and Figure 3 The illustrated 3D printing apparatus based on a linear light source includes: a rotating base 2, a movable scraper 3, a consumable material container 4, and a linear light source 1. The rotating base 2 is arranged parallel to the top of the consumable material container 4 and extends into the container 4 by a predetermined distance, so that the surface of the rotating base 2 contacts the printing material in the container 4. The printing material is a liquid photosensitive resin. The movable scraper 3 is arranged parallel to the central axis of the rotating base 2 and spaced at a predetermined distance from the surface of the rotating base 2. The linear light source 1 is arranged above the rotating base 2, parallel to the central axis of the rotating base 2, and spaced at a predetermined distance from the surface of the rotating base 2.

[0101] The 3D printing forming apparatus of this embodiment further includes: a controller, a memory, and a 3D printing forming program stored in the memory and run on the controller. When the controller executes the 3D printing forming program, it implements the 3D printing forming method based on linear light source in the above embodiment, so as to control the rotating base 2, the moving scraper 3 and the linear light source 1 to print the three-dimensional model.

[0102] Optionally, the linear light source 1 includes an ultraviolet lamp and a linear lens. The linear lens is used to generate an illumination pattern of the linear light source from the ultraviolet light emitted by the ultraviolet lamp according to the 3D printing method. In this embodiment, the linear lens can be a linear micromirror.

[0103] Optionally, the 3D printing forming apparatus of this embodiment further includes: a horizontal slide rail 6, and a movable scraper 3 is installed in the horizontal slide rail 6 so that the movable scraper 3 can move horizontally through the horizontal slide rail 6.

[0104] Optionally, the 3D printing forming apparatus of this embodiment further includes: a vertical slide rail 7, and a linear light source 1 is installed in the vertical slide rail 7 so that the linear light source 1 can move vertically through the vertical slide rail 7.

[0105] The 3D printing forming apparatus of this embodiment has the following characteristics:

[0106] (1) The linear light source uses a linear micromirror and is used in conjunction with an ultraviolet lamp as the curing light source for the photosensitive resin. This solves the technical problem that a high-precision, large-format micromirror group is required to form the traditional DLP process, and reduces the equipment cost of stereolithography.

[0107] (2) The rotating base and slide rail design are adopted, so that the rotating base can always be in a rotating state during the printing process, which overcomes the low efficiency problem of traditional SLA and other processes that rely on the reciprocating motion of the scraper and point light source scanning point by point.

[0108] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0109] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method of linear light source based 3D printing forming, characterized in that, The method comprises the following steps: S100: Obtain the geometric information of a 3D printing device, the 3D printing device comprising a rotating base, a moving scraper, a material consumption bin and a linear light source, and a three-dimensional coordinate system is established with the central axis of the rotating base as the X axis according to the geometric information of the 3D printing device; S200: Obtain a model file of a three-dimensional model to be printed, and topologically reconstruct the model vertex coordinate relationship in the model file to obtain a triangular mesh model of the three-dimensional model; S300: Project all vertices in the triangular mesh model onto the YOZ plane in the three-dimensional coordinate system to obtain a projection polygon of the triangular mesh model on the YOZ plane; S400: Take the projection point of the central axis of the rotating base on the YOZ plane as the center of a circle, and perform curved surface slicing on the projection polygon to obtain a plurality of layers of curved surface slices; S500: Calculate the sampling interval of a straight line to be filled and sampled in the i-th layer of curved surface slice according to the projection polygon and the position of the origin of the three-dimensional coordinate system, calculate the sampling angle step of the straight line to be filled and sampled in the sampling interval according to the projection width of the linear light source on the YOZ plane, and calculate the angle distribution corresponding to the straight line to be filled and sampled in the i-th layer of curved surface slice according to the sampling angle step; S600: According to the angle distribution, the intersection of the sampling straight line to be filled in the i-th layer of curved surface slice and the triangular mesh model is obtained; S700: Generate a linear light source mask of the i-th layer according to the filling scanning line segment, and print the i-th layer according to the linear light source mask; S400 comprises: Calculate the maximum distance from all projection points in the projection polygon to the origin of the three-dimensional coordinate system, and the origin of the three-dimensional coordinate system is the projection point of the central axis of the rotating base on the YOZ plane; According to the maximum distance, the radius of the rotating base and the thickness of each layer of curved surface slice, the radius of each layer of curved surface slice is calculated, and the projection polygon is curved surface sliced according to the radius of each layer of curved surface slice; According to the angle distribution, the intersection of the sampling straight line to be filled in the i-th layer of curved surface slice and the triangular mesh model is obtained; According to the radius Ri corresponding to the i-th layer of curved surface slice, the intersection point of the projection polygon and the circle on which the curved surface slice with the radius Ri is located is calculated, and the intersection points are connected to obtain the sampling interval of the straight line to be filled and sampled; According to the projection width of the linear light source on the YOZ plane, the sampling angle step of the straight line to be filled and sampled in the sampling interval is calculated, comprising: Connect the origin of the three-dimensional coordinate system with the two intersection points in each group of intersection points to obtain a first straight line and a second straight line intersecting with the Y axis, and calculate the included angle θmax between the first straight line and the positive Y axis and the included angle θmin between the second straight line and the positive Y axis; According to the projection width of the linear light source on the YOZ plane, the included angle θmax and the included angle θmin, the sampling angle step of the sampling straight line needed to be filled in the circular arc intersected by the projection polygon and the circle where the radius Ri is located is calculated.

2. The linear light source based 3D printing forming method according to claim 1, characterized in that, According to the angle distribution, the filling scan line segment intersected by the sampling straight line and the triangular mesh model in the i-th layer curved surface section is obtained, including: According to the angle distribution, the projection point coordinates of the sampling straight line on the YOZ plane are calculated. If the projection triangle covers the projection point coordinates, the three-dimensional coordinates of the intersection points of the sampling straight line and the triangular mesh model are calculated by using the intersection point calculation method of the straight line and the triangular mesh in the three-dimensional space. The three-dimensional coordinates of all the obtained intersection points are sorted in ascending order according to the X-axis component to obtain the ordered intersection point sequence of the sampling straight line and the triangular mesh model. According to the ordered intersection point sequence, all the intersection points are grouped two by two, and each group of two intersection points forms a filling scan line segment.

3. The linear light source based 3D printing forming method according to claim 2, characterized in that, According to the filling scan line segment, the linear light source mask of the i-th layer is generated, and the i-th layer is printed according to the linear light source mask, including: The moving doctor blade is moved to a position with a distance from the i-th layer curved surface section being the thickness of the preset each layer curved surface section; The surface linear velocity of the i-th layer curved surface section is set as V, the angular velocity ωi of the uniform rotation of the rotating base is calculated according to the radius Ri of the circle where the i-th layer curved surface section is located, and the rotating base is controlled to rotate at a uniform speed according to the angular velocity ωi. The corresponding printing consumables of the i-th layer are irradiated by using the linear light source and the linear light source mask to print the i-th layer.

4. A linear light source based 3D printing forming apparatus, characterized by, It includes: The rotating base, the moving doctor blade, the consumable material bin and the linear light source are arranged in parallel above the consumable material bin, and are arranged to extend into the consumable material bin by a preset distance, so that the surface of the rotating base contacts the printing consumables in the consumable material bin. The moving doctor blade is arranged in parallel with the central axis of the rotating base and is spaced apart from the surface of the rotating base by a preset distance. The linear light source is arranged above the rotating base, and the linear light source is parallel to the central axis of the rotating base and is spaced apart from the surface of the rotating base by a preset distance. The 3D printing forming device further comprises a controller, a memory and a 3D printing forming program stored in the memory and executable on the controller, and the controller implements the linear light source based 3D printing forming method according to any one of claims 1 to 3 when executing the 3D printing forming program, so as to control the rotating base, the moving doctor blade and the linear light source to print the three-dimensional model through the controller.

5. The linear light source based 3D printing forming apparatus according to claim 4, wherein, The linear light source comprises an ultraviolet lamp tube and a linear lens, and the linear lens is used to generate the irradiation pattern of the linear light source according to the 3D printing forming method.

6. The linear light source based 3D printing forming apparatus according to claim 4, wherein, The 3D printing forming device further comprises a horizontal sliding rail, and the moving scraper is installed in the horizontal sliding rail to move horizontally through the horizontal sliding rail.

7. The linear light source based 3D printing forming apparatus according to claim 4, wherein, The 3D printing forming device further comprises a vertical sliding rail, and the linear light source is installed in the vertical sliding rail to move vertically through the vertical sliding rail.

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