A rotational 3D printing method based on path generation through model affine transformation

Abstract

The present invention discloses a rotational 3D printing method based on model affine transformation path generation, comprising the following steps: S100, establishing a coordinate system; S200, acquiring and processing a model file; S300, slicing a plane and generating a path; and S400, completing printing according to instructions. By utilizing model affine transformation, the present invention applies a plane-based 3D printing data processing method to rotational 3D printing technology. The curved path generation method is simple and convenient, significantly reducing the complexity of the data processing process.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing, and in particular to a rotational 3D printing method based on generating a path through model affine transformation. Background Art

[0002] The prior art proposes a rotary FDM printing technology. For example, Chinese patent publication number CN116277958A discloses a 3D printing method and device based on a linear light source. The method includes: establishing a three-dimensional coordinate system based on the geometric information of the 3D printing device; obtaining a triangular mesh model of the three-dimensional model based on the model file of the three-dimensional model to be printed; projecting all vertices in the triangular mesh model onto the YOZ plane in the three-dimensional coordinate system to obtain a projected polygon; performing surface slicing on the projected polygon; calculating the sampling interval of the i-th layer of surface slices that need to be filled with sampling lines, calculating the sampling angle step length of the sampling lines that need to be filled in the sampling interval based on the projection width of the linear light source, and obtaining a filling scan line segment where the sampling line that needs to be filled in the i-th layer of surface section intersects with the triangular mesh model based on the sampling angle step length; and printing the three-dimensional model layer by layer based on the filled scan line segments, thereby improving the printing efficiency of the three-dimensional model. The defect is that the data processing method is relatively complicated: first, the calculation process of obtaining the surface slice contour of each layer is relatively complicated, and it is necessary to perform intersection calculation based on the mesh patch of the cylindrical surface and the three-dimensional model, and it is also required that the intersecting line segments after the surface slicing form an ordered contour ring; second, after the slice contour is obtained, a single filling path along the defense line of the rotating base axis is used. The typical path filling methods in planar FDM printing, such as Zigzag filling, Contour-Parallel filling, Spirals filling, etc., these path filling algorithms are complex to apply directly to the surface slice contour.

[0003] In this field, conventional plane-based 3D printing data processing methods cannot be directly used in the above-mentioned rotary FDM printing technology. This is because in rotary FDM printing technology, as the number of printing layers increases, the forming radius corresponding to the forming surface deposited by the molten extruded material also gradually increases. If the processing control instructions generated by conventional three-dimensional model data processing are directly used for rotary FDM printing, the rotation instructions used to control the rotation axis will inevitably cause the actual rotation angle of the rotation axis to be too large, which will eventually lead to problems such as the physical geometric dimensions after rotary FDM printing not matching the three-dimensional model dimensions, resulting in printing failure.

[0004] In order to solve the above problems, a method for generating 3D printing surface paths based on model affine transformation rotation is proposed. Summary of the Invention

[0005] In order to solve the above problems, the present invention proposes a rotational 3D printing method based on model affine transformation to generate a path, which is characterized by comprising the following steps:

[0006] S100, establishing a coordinate system: The rotary 3D printing device includes a rotary base and a printing nozzle. A mathematical model is established based on the obtained geometric information of the rotary 3D printing device. A three-dimensional coordinate system is established with the highest point of the rotary base and a cylindrical surface line passing through the highest point as the origin O and the Y axis respectively.

[0007] S200, obtaining and processing a model file: obtaining a model file of a 3D model to be printed, performing mesh densification processing to obtain a 3D mesh model, and performing a mapping transformation operation on vertices of the 3D mesh model, thereby achieving an affine transformation of the 3D model;

[0008] S300, plane slicing and path generation: performing plane slicing and path generation processing on the affine 3D model;

[0009] S400, completing printing according to the instruction: the generated printing instruction drives the rotating 3D printing device to complete printing.

[0010] As a preferred technical solution of the present invention, the grid densification process in step S200 adopts a classical grid subdivision algorithm, which includes but is not limited to multiple Hermite spatial interpolation subdivisions, Loop subdivisions, and Catmull-Clark subdivisions.

[0011] As a preferred technical solution of the present invention, the mapping transformation operation in step S200 refers to traversing the model vertex coordinates in the model file and performing a mapping transformation operation on each vertex coordinate as follows:

[0012] i. The preset model vertex is P (x, y, z), the center of the rotating base is Q, and the rotation radius of the rotating base is R0. The length between point P and the center of the rotating base Q is L. i ;

[0013] ii. On the XOZ plane, calculate the angle α between the QP ray and the QZ ray, where α is in radians;

[0014] iii. Calculate the spatial coordinates P'(x', y', z') of point P after mapping according to the following mapping formula.

[0015] P'(x', y', z')=(L i *α, y, L i -R0)

[0016] And P' is used as the vertex coordinates after affine transformation of the three-dimensional model.

[0017] As a preferred technical solution of the present invention, the three-dimensional model is placed directly above the rotating base.

[0018] As a preferred technical solution of the present invention, the plane slicing adopts the STL plane slicing algorithm.

[0019] As a preferred technical solution of the present invention, the planar path generation adopts the FDM path filling algorithm.

[0020] The beneficial effects of the present invention are as follows:

[0021] The rotational 3D printing method based on model affine transformation path generation of the present invention applies the plane-based 3D printing data processing method to rotational 3D printing technology by adopting the data processing strategy of model affine transformation. The surface path generation method is simple and convenient, avoiding the complex data processing process of conventional surface slicing strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a workflow diagram of the present invention.

[0023] Figure 2 This is a schematic diagram of the position of the rotating base and the three-dimensional model to be printed.

[0024] Figure 3 It is a side view schematic diagram of the rotating base and mesh model before affine transformation.

[0025] Figure 4 It is a side view schematic diagram of the rotating base and mesh model after affine transformation.

[0026] Figure 5 It is the rendering result processed by conventional plane slicing and path generation algorithm.

[0027] Figure 6 It is the result of rotating 3D printed objects based on the affine transformation of the model.

[0028] Reference numerals: 1. Rotation base, 2. Three-dimensional model. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0030] See also Figure 1-4 The present invention proposes a rotational 3D printing method based on a model affine transformation path generation method, comprising the following steps:

[0031] S100: Establishing a coordinate system: The rotating 3D printing device includes a rotating base 1 and a printing nozzle. Based on the obtained geometric information of the rotating 3D printing device, a mathematical model is established: Figure 2 The XOZ plane is obtained by horizontally projecting the rotating base 1 along its central axis, where the Z axis is vertically upward and the X axis is horizontally to the right. The highest point of the projected circle of the rotating base 1 is taken as the origin O, and the direction of the rotating central axis of the rotating base 1 is taken as the Y axis. Figure 3 The Y axis is perpendicular to the XOZ plane and points inward, thus conforming to the characteristics of the right-hand coordinate system, thus completing the establishment of the three-dimensional coordinate system;

[0032] S200, obtaining and processing a model file: obtaining a model file of the three-dimensional model 2 to be printed, performing mesh densification processing to obtain a three-dimensional mesh model, and performing a mapping transformation operation on the vertices of the three-dimensional mesh model, thereby achieving an affine transformation of the three-dimensional model;

[0033] S300, plane slicing and path generation: performing plane slicing and path generation processing on the affine three-dimensional model 2;

[0034] S400, completing printing according to the instruction: the generated printing instruction drives the rotating 3D printing device to complete printing.

[0035] In order to improve the accuracy of model surface details, ensure the accuracy of geometric shapes, avoid printing defects, accurately simulate physical properties and effectively generate support structures, it is necessary to perform mesh densification on the printed three-dimensional model 2 (such as an STL model). The mesh densification process uses classic mesh subdivision algorithms, such as multiple Hermite spatial interpolation subdivision, Loop subdivision, Catmull-Clark subdivision, etc.

[0036] The mapping transformation operation in step S200 refers to traversing the model vertex coordinates in the model file and performing a mapping transformation operation on each vertex coordinate as follows:

[0037] i. The preset model vertex is P (x, y, z), the center of the rotating base 1 is Q, and the rotation radius of the rotating base 1 is R0. The length between point P and the center of the rotating base 1 Q is L i ;

[0038] ii. On the XOZ plane, calculate the angle α between the QP ray and the QZ ray, where α is in radians;

[0039] iii. Calculate the spatial coordinates P'(x', y', z') of point P after mapping according to the following mapping formula.

[0040] P'(x', y', z')=(L i *α, y, L i -R0)

[0041] And P' is used as the vertex coordinates of the 3D model 2 after affine transformation.

[0042] The 3D printing slicing algorithm is used to perform plane slicing on the mesh model after affine transformation. Specifically, the existing classic STL plane slicing algorithms are used, such as the surface intersection slicing algorithm, the line-surface intersection slicing algorithm, and the perpendicular intersection slicing algorithm.

[0043] A planar path filling algorithm is used to fill the path of the sliced ​​contour. Specifically, the existing classic FDM path filling algorithms are used, such as Zigzag filling, Contour-Parallel filling, Spirals filling, etc. This test uses Contour-Parallel and Zigzag path filling algorithms.

[0044] Use planar 3D printing software such as Cura, IceSL, etc. This type of software basically integrates the current mainstream planar slicing algorithms and typical path filling algorithms, and can directly process data.

Claims

1. A rotational 3D printing method based on model affine transformation path generation, characterized in that: The following steps are involved: S100, establishing a coordinate system: The rotary 3D printing device includes a cylindrical rotary base and a printing nozzle, and a mathematical model is established based on the obtained geometric information of the rotary 3D printing device; A three-dimensional coordinate system is established with the highest point of the rotating base and the cylindrical line passing through the highest point as the origin O and the Y axis respectively; S200, obtaining and processing a model file: obtaining a model file of a 3D model to be printed, performing mesh densification processing to obtain a 3D mesh model, and performing a mapping transformation operation on vertices of the 3D mesh model, thereby achieving an affine transformation of the 3D model; The mapping transformation operation refers to traversing the model vertex coordinates in the model file and performing a mapping transformation operation on each vertex coordinate as follows: i. The preset model vertex is P (x, y, z), the center of the rotating base is Q, and the rotation radius of the rotating base is R0. The length between point P and the center of the rotating base Q is L. i ; ii. On the XOZ plane, calculate the angle α between the QP ray and the QZ ray, where α is in radians; iii. Calculate the spatial coordinates P'(x', y', z') of point P after mapping according to the following mapping formula. P'(x',y',z')=(L i *α,y,L i -R0) And use P' as the vertex coordinates after affine transformation of the three-dimensional model; S300, plane slicing and path generation: performing plane slicing and path generation processing on the affine 3D model; S400, completing printing according to the instruction: the generated printing instruction drives the rotating 3D printing device to complete printing.

2. The rotational 3D printing method based on model affine transformation path generation according to claim 1, characterized in that: The grid densification process in step S200 adopts a classic grid subdivision algorithm, which includes multiple Hermite spatial interpolation subdivisions, Loop subdivisions, or Catmull-Clark subdivisions.

3. The rotational 3D printing method based on model affine transformation path generation according to claim 1, characterized in that: The three-dimensional model is placed directly above the rotating base.

4. The rotational 3D printing method based on model affine transformation path generation according to claim 1, characterized in that: The plane slicing adopts the STL plane slicing algorithm.

5. The rotational 3D printing method based on model affine transformation path generation according to claim 1, characterized in that: The planar path generation adopts the FDM path filling algorithm.

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