Support design method for 3D printing and 3D printing method

Abstract

The invention discloses a support design method for 3D printing and a 3D printing method. The support design method comprises the steps that a structure with texture patterns and the lower surface smaller than 45 degrees is selected; according to the shape of the outer surface of the to-be-supported design structure, a curved surface or a plane consistent with the shape of the outer surface of the to-be-supported design structure is formed; or, when the structure with the texture patterns in the to-be-printed workpiece is generated on the basis of the original smooth structural surface through the three-dimensional software, the curved surface or the plane corresponding to the to-be-supported design structure is selected from the original smooth structural surface; translating the curved surface or the plane to enable the distance between the curved surface or the plane and the root of the highest convex surface of the texture patterns in the design structure to be supported to be one third to one half of the maximum convex length; and on the basis of the translated curved surface or plane, supporting design is carried out below the curved surface or plane. The supporting design efficiency of the workpiece with the pattern characteristics can be improved, the forming capacity of the workpiece is improved, and the appearance quality of the pattern structure is also improved.

Description

Technical Field

[0001] The present application relates to the field of additive manufacturing technology, and in particular to a support design method for 3D printing and a 3D printing method. Background Art

[0002] Additive manufacturing technology (also known as 3D printing technology) is a rapid manufacturing technology that controls laser scanning layer by layer and stacks layers to form a three-dimensional object. The process flow is as follows: first, the three-dimensional model of the workpiece is sliced ​​to obtain the cross-sectional information of each layer of the workpiece; the powdered material is evenly spread on the surface of the work platform, and the laser selectively melts the powder according to the system instructions; after a section is completed, a new layer of material is spread, and the scanning continues to be selective according to the cross-sectional information corresponding to the three-dimensional object; according to this method, the next section is scanned for powder spreading, and finally a three-dimensional object is obtained.

[0003] As the 3D printing industry matures, the 3D printing market is now growing. From the initial high-end manufacturing such as aerospace, aviation, medical, scientific research, and jewelry fields, it has gradually moved towards civilian use, making more and more people start to consume 3D printed products directly or indirectly. However, there are often some texture structures with small structural features but a large number in civilian products, which are usually called pattern structures. In particular, some molds have high requirements for the appearance of patterns, which will increase the requirements for design and process. As we all know, in the process of metal 3D printing, structures with small overhang angles cannot be directly printed and formed. Usually 45° is regarded as the critical angle. If the overhang angle is greater than 45°, no support is required. If the overhang angle is less than 45°, support needs to be set on the lower surface of the structure to assist the workpiece molding. Since there are many patterns in civilian workpieces at present, and the patterns are mainly concentrated on the internal surface of the workpiece, there are many patterns with large areas, small features, large numbers, small inclination angles, and even overhanging surfaces, which greatly increases the difficulty of printing. Therefore, support needs to be added to the lower surface of these pattern features to assist in successful printing. However, this adds a huge workload and high difficulty to our support design, because the workpiece format used in the current support design software is stl, which is composed of a large number of small triangular faces. When we design or edit the support for the workpiece, we are actually processing countless triangular faces on the model surface. Since the pattern surfaces that need to be supported are inconsistent and the pattern surfaces are discontinuous, this greatly increases the difficulty of selecting support surfaces during support design, and it is even easy to miss some small pattern surfaces, resulting in no support for some of the positions of the missed selected surfaces, which in turn leads to poor printing quality of these lower surfaces, and even causes local warping, resulting in workpiece printing failure. Summary of the invention

[0004] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a support design method for 3D printing and a 3D printing method. The support design method of the present invention can greatly improve the support design efficiency of workpieces with pattern features, and the patterned portion of the lower surface of the workpiece can be completely supported, which can not only greatly improve the forming ability of the workpiece, but also greatly improve the appearance quality of the pattern structure.

[0005] In order to achieve the above object, the present invention provides a support design method for 3D printing, which is applied to a structure with a texture pattern and a lower surface angle less than 45° in a workpiece to be printed, and the method comprises the following steps:

[0006] Step S1, select a structure with a texture pattern and a lower surface angle less than 45 degrees, and record it as a design structure to be supported;

[0007] Step S2, forming a curved surface or plane that is consistent with the outer surface shape of the design structure to be supported according to the outer surface shape of the design structure to be supported, and the curved surface or plane does not have a texture pattern; or, when a structure with a texture pattern in the workpiece to be printed is generated on the basis of an original smooth structural surface through three-dimensional software, selecting a curved surface or plane corresponding to the design structure to be supported from the original smooth structural surface;

[0008] Step S3, translating the curved surface or plane so that the distance between the curved surface or plane and the root of the highest raised surface of the texture pattern in the supported design structure is one third to one half of the maximum raised length;

[0009] Step S4: Based on the translated curved surface or plane, support design is performed underneath it.

[0010] As a further preferred embodiment of the present invention, forming a curved surface or a plane consistent with the outer surface shape of the designed structure to be supported according to the outer surface shape of the designed structure to be supported specifically comprises the following steps:

[0011] All raised surfaces in the design structure to be supported are selected, and points are randomly found on all raised surfaces along the extension trend of the texture pattern. According to the positions of all randomly found points, a new curved surface or plane is determined, and the curved surface or plane is consistent with the outer surface shape of the design structure to be supported.

[0012] As a further preferred embodiment of the present invention, forming a curved surface or a plane consistent with the outer surface shape of the designed structure to be supported according to the outer surface shape of the designed structure to be supported specifically comprises the following steps:

[0013] Select all the surfaces between the convex surface and the concave surface in the design structure to be supported, and randomly find points on all the surfaces along the extension trend of the texture pattern. According to the positions of all the randomly found points, determine a new curved surface or plane, and the curved surface or plane is consistent with the outer surface shape of the design structure to be supported.

[0014] As a further preferred embodiment of the present invention, the curved surface or plane has the same length and width as the designed structure to be supported.

[0015] As a further preferred embodiment of the present invention, the distance between the curved surface or the plane and the root of the highest raised surface in the designed structure to be supported is half of the maximum raised length.

[0016] As a further preferred embodiment of the present invention, the distance between the curved surface or the plane and the root of the highest protruding surface in the designed structure to be supported is -0.02 to 0.15 mm of the maximum protruding length.

[0017] As a further preferred embodiment of the present invention, the convex or concave length and width of the convex surface and concave surface of the texture pattern are both less than or equal to 2 mm.

[0018] As a further preferred embodiment of the present invention, the specific parameters of the support design are: Z-axis offset is 0-0.1 mm, no-support offset is 0, and vertical support wall offset is 0.

[0019] As a further preferred embodiment of the present invention, when there are two or more discontinuous design structures to be supported in the workpiece to be printed, the support design method described in any one of claims 1 to 8 is used to perform support design for each design structure to be supported.

[0020] The present invention also provides a 3D printing method, comprising the following steps:

[0021] Select all the design structures to be supported from the workpiece to be printed, and use any of the support design methods for 3D printing described above to perform support design on each design structure to be supported to obtain a first support structure; the design structure to be supported is a structure with a texture pattern and a lower surface angle of less than 45°;

[0022] For all structures in the workpiece to be printed except the structure to be supported, support design is performed according to the prior art to obtain a second support structure; and the first support structure, the second support structure and the workpiece to be printed are formed together through 3D printing.

[0023] The support design method for 3D printing and the 3D printing method of the present invention construct a curved surface or plane without texture patterns for the support design structure, and perform support design under the curved surface or plane to form a support structure, so that it can greatly improve the support design efficiency of the workpiece to be printed with pattern features, and the part with patterns on the lower surface of the workpiece can be fully supported and propped up, which can not only well improve the forming ability of the workpiece, but also greatly improve the appearance quality of the pattern structure. In addition, the support structure formed by this method has a complete tooth shape and continuity, and the teeth of the support will not extend into the position where the pattern is recessed on the texture, which will not cause trouble for post-processing, and can ensure the printing effect, so that the workpiece can be printed smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A method flow chart of an embodiment of a support design method for 3D printing provided by the present invention;

[0025] Figure 2 It is a schematic diagram of the local structure of the workpiece to be printed in the present invention;

[0026] Figure 3 A working state diagram of an embodiment of the support design method for 3D printing provided by the present invention;

[0027] Figure 4 A working state diagram of another embodiment of the support design method for 3D printing provided by the present invention;

[0028] Figure 5 A working state diagram of another embodiment of the support design method for 3D printing provided by the present invention;

[0029] Markings in the figure:

[0030] 1. Workpiece to be printed, 2. Intermediate surface, 3. First support structure. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0032] like Figure 1 As shown, the support design method for 3D printing of the present invention is applied to a structure with a texture pattern and a lower surface angle less than 45° in a workpiece to be printed, and the method comprises the following steps:

[0033] Step S1, select a structure with a texture pattern and a lower surface angle less than 45°, and record it as a design structure to be supported; Figure 2 As shown, Figure 2Medium orange and orange-red represent different degrees of inclination of the design structure to be supported. The smaller the angle, the closer the color is to red.

[0034] Step S2, forming a curved surface or plane that is consistent with the outer surface shape of the design structure to be supported according to the outer surface shape of the design structure to be supported, and the curved surface or plane has no texture pattern; or, when the structure with texture pattern in the workpiece 1 to be printed is generated on the basis of the original smooth structural surface through three-dimensional software, the curved surface or plane corresponding to the design structure to be supported is selected from the original smooth structural surface; the curved surface or plane can be called the middle surface 2, and preferably, the middle surface 2 has the same length and width as the design structure to be supported. Of course, the length and width of the middle surface 2 can also be slightly larger than the length and width of the design structure to be supported. Figure 3 As shown, Figure 3 The purple-red part in the middle represents the newly created middle surface 2; Figure 4 As shown, the Figure 4 Multiple intermediate surfaces 2 are newly created, such as the blue part, the purple-red part, and so on.

[0035] Step S3, translate the curved surface or plane so that the distance between the curved surface or plane and the root of the highest raised surface of the texture pattern in the supported design structure is one-third to one-half of the maximum raised length; preferably, the distance between the curved surface or plane and the root of the highest raised surface in the supported design structure is one-half of the maximum raised length, or the distance between the curved surface or plane and the root of the highest raised surface in the supported design structure is -0.02 to 0.15 mm of the maximum raised length, which can further ensure that the generated support has a complete tooth shape and continuity, and further ensure the printing effect. The maximum raised length here is the raised length of the highest raised surface.

[0036] Step S4: Based on the translated curved surface or plane, support design is performed underneath it.

[0037] As an embodiment of the present invention, forming a curved surface or a plane consistent with the outer surface shape of the designed structure to be supported according to the outer surface shape of the designed structure to be supported specifically includes the following steps:

[0038] All raised surfaces in the design structure to be supported are selected, and points are randomly found on all raised surfaces along the extension trend of the texture pattern. According to the positions of all randomly found points, a new curved surface or plane is determined, and the curved surface or plane is consistent with the outer surface shape of the design structure to be supported.

[0039] As another embodiment of the present invention, forming a curved surface or a plane consistent with the outer surface shape of the designed structure to be supported according to the outer surface shape of the designed structure to be supported specifically includes the following steps:

[0040] Select all the surfaces between the convex surface and the concave surface in the design structure to be supported, and randomly find points on all the surfaces along the extension trend of the texture pattern. According to the positions of all the randomly found points, determine a new curved surface or plane, and the curved surface or plane is consistent with the outer surface shape of the design structure to be supported.

[0041] It should be explained here that random point finding refers to randomly finding one or more points for all the above-mentioned raised surfaces or all surfaces. It does not necessarily mean that points need to be found evenly on every raised surface or surface. It is mainly about randomly finding points along the extension trend of the texture pattern. It can be implemented by existing software. It belongs to the existing technology, so it will not be elaborated on in detail.

[0042] In order to provide better support for the lower surface of the textured pattern, preferably, the specific parameters of the support design are: Z-axis offset is 0-0.1 mm, no-support offset is 0, and vertical support wall offset is 0.

[0043] It should be noted here that the technical solution of the present application is preferably applied to the convex or concave length and width of the convex and concave surfaces of the texture pattern that are less than or equal to 2mm. The specific meaning of this sentence is: the convex length and width of all convex surfaces are less than or equal to 2mm; and the concave length and width of all concave surfaces are less than or equal to 2mm. If the convex or concave length and width of the convex and concave surfaces of the texture pattern exceed this size, in order to better ensure the support effect of the texture pattern, the pattern needs to be supported separately according to the size of the area.

[0044] Specifically, when there are two or more discontinuous design structures to be supported in the workpiece 1 to be printed, the support design method described in any of the above items is used for each design structure to be supported; of course, if there are several continuous design structures to be supported, they only need to be merged into one design structure to be supported, and support design is performed on it according to the above-mentioned support design method.

[0045] The present invention also provides a 3D printing method, comprising the following steps:

[0046] All the design structures to be supported are selected from the workpiece 1 to be printed, and the support design method for 3D printing described in any one of the above items is used to perform support design on each design structure to be supported to obtain a first support structure 3, such as Figure 5 As shown; the designed structure to be supported is a structure with a texture pattern and a lower surface angle less than 45°;

[0047] For all structures in the workpiece 1 to be printed except the structure to be supported, support design is performed according to the prior art to obtain a second support structure; and the first support structure 3 and the second support structure are formed together with the workpiece 1 to be printed by 3D printing.

[0048] It should be noted here that since the core of the protection of this application is to design a support for the structure with a texture and a lower surface less than 45° in the workpiece 1 to be printed to obtain the first support structure 3 according to the above-mentioned technical scheme of this application, the design of the second support structure and the specific method of overall printing of the first and second support structures and the workpiece 1 to be printed will not be elaborated in detail, which belongs to the conventional technology in this field.

[0049] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the technical solution of the present invention is specifically described below in the form of embodiments.

[0050] Embodiment 1

[0051] Place the workpiece in the support design software, find the position with texture pattern and less than 45° that needs to be supported, record it as the design structure to be supported, select all the raised surfaces in the design structure to be supported, and randomly find points on all the raised surfaces along the extension trend of the texture pattern. According to the positions of all the randomly found points, determine a new curved surface or plane (also called middle surface 2), and the curved surface or plane is consistent with the outer surface shape of the design structure to be supported; since the position of this middle surface 2 is at the outermost end of the pattern, there are fewer positions in contact with the entire pattern, and the support made in this way will not be able to contact the pattern well, so the newly established surface must be offset, and the offset distance is half the size of the protrusion of the pattern, and the offset direction is to move along the root direction of the pattern. For example, the protrusion size of the pattern on the texture is 0.2mm, we draw a new surface on the outermost side of the pattern, and then offset this new surface inward so that the distance between the outermost side of the pattern and the new surface is 0.2÷2=0.1mm. Then import this new surface together with the original workpiece with texture into the platform that needs to be supported by the workpiece, and keep the relative position with the workpiece unchanged. When designing supports, the surfaces at these textures can directly select the newly created surfaces to generate supports (such as Figure 3 As shown), after the support design is completed, the support generated on the newly created surface is exported separately, and the export method of the workpiece remains unchanged. In this way, the support design of the small triangular facets at the texture can be quickly completed. Moreover, this design method can not only ensure that the generated support has a complete tooth shape and continuity, but also that the teeth of the support will not extend into the recessed position of the pattern on the texture, which will not cause trouble for post-processing, and can ensure the printing effect, so that the workpiece can be printed smoothly.

[0052] Embodiment 2

[0053] Structures with large-area patterned textures are generally designed and generated in 3D software, and are generated on the basis of the original smooth structural surface. Therefore, when designing the support at the lower surface of the large-area patterned texture structure with an angle of less than 45°, we can first confirm the patterned surface that needs to be supported in the support design software, and then export the original drawing before the pattern is generated from the 3D software in STL format, and align it with the drawing generated with the texture in the support design software, and place it in the right position. In the original drawing without pattern (denoted as B), copy the surface that needs to be supported in the original drawing with pattern (denoted as A), and then hide or delete B, leaving only the A drawing and the copied smooth surface as the newly created surface (also called middle surface 2). Before the formal support design, the new surface is offset, and the offset distance is (the protruding height of the pattern -0.02 to 0.15mm), and the offset surface is marked with a color to facilitate distinction when making supports. When designing supports, the first step is to select the surface that needs to be supported on the entire merged workpiece. For the original smooth curved surface on the workpiece, the surface selection is still carried out according to the conventional method. For the large area texture on the workpiece, the new surface that has been merged with the workpiece in the previous step is selected (the length and width of the single pattern size are limited to ≤2mm at the same time. If it exceeds this size, the pattern needs to be supported separately according to the size of the area). Then, the support design is carried out according to the conventional method. After the support is designed, the support file is exported and saved in the folder of the previously exported workpiece drawing. It is worth noting that in the process of support design, the support parameters need to be adjusted for the supports generated on the new surface, because these supports will eventually contact the concave and convex surface of the pattern. In order to make them support the lower surface of the concave and convex surface of the pattern better, the "Z-axis offset" in the support parameters of these positions needs to be set to 0~0.1mm, the "no support offset" is set to 0, and the "vertical support wall offset" is set to 0.

[0054] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A support design method for 3D printing, applied to a structure with a texture pattern and a lower surface angle less than 45° in a workpiece to be printed, characterized in that: The method comprises the following steps: Step S1, select a structure with a texture pattern and a lower surface angle less than 45 degrees, and record it as a design structure to be supported; Step S2, forming a curved surface or plane that is consistent with the outer surface shape of the design structure to be supported according to the outer surface shape of the design structure to be supported, and the curved surface or plane does not have a texture pattern; or, when a structure with a texture pattern in the workpiece to be printed is generated on the basis of an original smooth structural surface through three-dimensional software, selecting a curved surface or plane corresponding to the design structure to be supported from the original smooth structural surface; Step S3, translating the curved surface or plane so that the distance between the curved surface or plane and the root of the highest raised surface of the texture pattern in the supported design structure is one third to one half of the maximum raised length; Step S4: Based on the translated curved surface or plane, support design is performed underneath it.

2. The support design method for 3D printing according to claim 1, characterized in that: Forming a curved surface or a plane that is consistent with the outer surface shape of the designed structure to be supported according to the outer surface shape of the designed structure to be supported specifically comprises the following steps: All raised surfaces in the design structure to be supported are selected, and points are randomly found on all raised surfaces along the extension trend of the texture pattern. According to the positions of all randomly found points, a new curved surface or plane is determined, and the curved surface or plane is consistent with the outer surface shape of the design structure to be supported.

3. The support design method for 3D printing according to claim 1, characterized in that: Forming a curved surface or a plane that is consistent with the outer surface shape of the designed structure to be supported according to the outer surface shape of the designed structure to be supported specifically comprises the following steps: Select all the surfaces between the convex surface and the concave surface in the design structure to be supported, and randomly find points on all the surfaces along the extension trend of the texture pattern. According to the positions of all the randomly found points, determine a new curved surface or plane, and the curved surface or plane is consistent with the outer surface shape of the design structure to be supported.

4. The support design method for 3D printing according to any one of claims 1 to 3, characterized in that: The curved surface or plane has the same length and width as the designed structure to be supported.

5. The support design method for 3D printing according to claim 4, characterized in that: The distance between the curved surface or the plane and the root of the highest raised surface in the designed structure to be supported is half of the maximum raised length.

6. The support design method for 3D printing according to claim 4, characterized in that: The distance between the curved surface or the plane and the root of the highest protruding surface in the designed structure to be supported is -0.02 to 0.15 mm of the maximum protruding length.

7. The support design method for 3D printing according to claim 1, characterized in that: The convex or concave length and width of the convex surface and concave surface of the texture pattern are both less than or equal to 2mm.

8. The support design method for 3D printing according to claim 1, characterized in that: The specific parameters of the support design are: Z-axis offset is 0-0.1 mm, no support offset is 0, and vertical support wall offset is 0.

9. A support design method for 3D printing, characterized in that: When there are two or more discontinuous design structures to be supported in the workpiece to be printed, support design is performed for each design structure to be supported using the support design method described in any one of claims 1 to 8.

10. A 3D printing method, characterized in that: The following steps are involved: Selecting all the design structures to be supported from the workpiece to be printed, and performing support design on each design structure to be supported using the support design method for 3D printing described in any one of claims 1 to 9 to obtain a first support structure; The designed structure to be supported is a structure with a texture pattern and a lower surface angle less than 45°; For all structures in the workpiece to be printed except the structure to be supported, support design is performed according to the prior art to obtain a second support structure; The first support structure, the second support structure and the workpiece to be printed are formed together through 3D printing.

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