A printing model and fabrication method based on gradient offset non-contact support

Abstract

This invention relates to a printed model and preparation method based on gradient offset non-contact support, comprising the following steps: adjusting the Z-axis offset of the supported model to obtain a first support with a single offset; using the Z-coordinate of the minimum point on the top surface of the first support as a reference, subtracting the Z-coordinate values ​​of all points on the top surface of the first support from the Z-coordinate value of the minimum point with the smallest distance to obtain a series of height differences, denoted as Δh; using the formula Znew=Z+kΔh, calculating all Z-coordinate values ​​Znew based on the Z-coordinate values ​​of all points on the top surface of the first support, the height difference Δh, and the gradient support ratio coefficient k, to obtain a gradient non-contact support surface, wherein there is a gradient gap layer between the gradient non-contact support surface and the supported model; performing an AND operation between the gradient non-contact support surface and the first support to obtain a gradient non-contact second support; combining the second support and the supported model and importing them into a 3D photopolymerization printer, and printing the printed model based on gradient offset non-contact support layer by layer using paste.

Description

Technical Field

[0001] This invention belongs to the field of 3D printing technology, specifically relating to a printing model and preparation method based on gradient offset non-contact support. Background Technology

[0002] 3D photopolymer printing is a high-precision, high-efficiency printing method widely used in precision manufacturing, construction, and dentistry. Photopolymer printing technology based on high-viscosity materials often requires the addition of supports to the model during the printing process. The support structure must ensure sufficient strength to prevent damage, tipping, or collapse of the supported model during printing, and it must also be easily detachable from the model after printing without damaging its surface. Currently, support structures for 3D photopolymer printing are mainly divided into two categories: contact supports and non-contact supports.

[0003] Contact supports are those that directly contact the model. These supports are relatively easy to add; by adjusting the angle and height of the supported model, contact supports are readily available. They also offer good stability during printing, are not easily broken during horizontal coating processes, and provide excellent support for the model. Therefore, contact supports are widely used in 3D printing. However, because the support is in direct contact with the model, it can leave residue on the model or damage its surface during subsequent separation, affecting the model's quality. Therefore, there is an urgent need to improve contact supports. This led to the development of non-contact supports.

[0004] Non-contact support optimizes the support method compared to contact support. It utilizes the supporting properties of a high-viscosity material to separate the model from the support at a certain distance. This gap is filled with the high-viscosity material to support the model above. During printing, the high-viscosity material in the gap does not solidify, allowing the model and support to separate. However, in practice, the distance between the support and the model is difficult to adjust automatically, requiring manual adjustment, which is inconvenient. Furthermore, the surface of the model is often not flat, while the gap between the non-contact support and the model remains constant. This causes the supported model to adhere to the support to some extent during printing due to the fluidity of the high-viscosity material, resulting in poor separation during the subsequent process.

[0005] Therefore, there is an urgent need to invent a printed model that can be easily separated from the support. Summary of the Invention

[0006] To address the technical problems existing in the prior art, one of the objectives of this invention is to provide a method for preparing a printed model based on a non-contact support with a gradual offset. The distance between the non-contact support and the model is gradually changed and easily adjustable, which is beneficial for obtaining a printed model that is easy to separate from the support.

[0007] The second objective of this invention is to provide a printing model based on non-contact support with gradient offset.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A method for fabricating a printed model based on gradient offset non-contact support includes the following steps:

[0010] Step 1: Import the model to be supported into the software, use the volumetric support function in the software's support generation function to adjust the Z-axis offset of the model to obtain the first support with a single offset.

[0011] Step 2: Use software to identify the top surface of the first support and all the minimum points on the top surface. Using the Z coordinate of the minimum point on the top surface of the first support as a reference, subtract the Z coordinate value of all points on the top surface of the first support from the Z coordinate value of the minimum point with the smallest distance to obtain a series of height differences, denoted as Δh.

[0012] Step 3: Using the formula Znew=Z+kΔh, calculate all Z coordinate values ​​Znew based on the Z coordinate values ​​of all points on the top surface of the first support, the height difference Δh, and the gradual support ratio coefficient k, to obtain the corresponding proportion of the gradual non-contact support surface. There is a gradual gap layer between the gradual non-contact support surface and the supported model.

[0013] Step 4: Perform a bitwise AND operation between the gradient non-contact support surface and the first support to obtain the gradient non-contact second support;

[0014] Step 5: Combine the second support and the supported model and import them into the 3D photopolymerization printer. Use the paste to print the solid supported model and the second support layer by layer, as well as the gradient gap layer between the supported model and the second support to maintain the paste shape, thereby obtaining a printed model based on the gradient offset non-contact support.

[0015] Furthermore, before printing, a Boolean operation is performed between the second support and the hollow structure model in the software to obtain a third support with an array of holes.

[0016] Furthermore, the hollow structure model includes multiple parallel vertical holes and multiple parallel horizontal holes. The diameter of the vertical holes remains constant from top to bottom, while the diameter of the horizontal holes gradually decreases from top to bottom.

[0017] Furthermore, the solid parts of the hollow structure model are processed using shelling technology, turning them into hollow supports.

[0018] Furthermore, the gradient gap layer is printed using a high-viscosity material.

[0019] Furthermore, the high-viscosity material is a photosensitive material.

[0020] Furthermore, the viscosity of the photosensitive material ranges from 50 Pa·s to 100 Pa·s.

[0021] Furthermore, the height of the gradient gap layer is 1.5-4 times the depth of the photopolymerization process.

[0022] Furthermore, the supported model and the second support use the same or different printing parameters.

[0023] A printing model based on gradient offset non-contact support is prepared using a printing model preparation method based on gradient offset non-contact support.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) Reduce the process of manually adjusting the support.

[0026] Existing methods for adding non-contact supports can quickly add supports to the supported model using software, and the non-contact support purpose can be achieved by adjusting the offset, greatly simplifying the complex steps of manually adding supports. However, machine-added non-contact supports are too fixed, and the distance between the support and the supported model is difficult to adjust automatically, requiring manual adjustment. This invention utilizes the relationship between the height of the gradient non-contact support surface and the bottom surface of the supported model to obtain a functional relationship. Inputting this functional relationship into the software enables one-step generation of gradient offset non-contact supports, eliminating the need for manual adjustment of the gap height. Moreover, for different supported models, the relationship between the height of the gradient non-contact support surface and the bottom surface of the supported model can be quickly obtained. Using this functional relationship, multiple gradient offset non-contact supports can be generated in a short time, exhibiting extremely high efficiency and practicality.

[0027] (2) Reduce the difficulty of separating the supporting and supported models

[0028] Existing methods for generating non-contact supports for models, while theoretically making separation easier since the supports beneath the supported model are not in direct contact, often encounter difficulties during actual printing. These difficulties arise due to the small, fixed gap between the non-contact support and the supported model, the fluidity of high-viscosity materials, and printing parameter settings, making it easy for the support to come into contact with the supported model at the edge, hindering separation. This invention, however, employs a gradient offset non-contact support. Utilizing the minimum height difference between the bottom surface of the supported model and the top surface of the non-contact support, and incorporating the corresponding coordinate transformation formula, the non-contact support undergoes a gradual change. This prevents the support from sticking to the supported model, reducing separation difficulty and maximizing the integrity of the supported model.

[0029] (3) Reduce the amount of material used in the support components.

[0030] Existing non-contact support generation methods for models often generate a continuous solid support, which is then a useless part after printing, resulting in material waste during the printing process. This invention utilizes Boolean operations—specifically, the "AND" operation—to perform calculations between the support and the hollow structure model, creating a regular perforated structure inside and on the surface of the support. No material is needed between these perforations, thus reducing material usage. Furthermore, the hollow structure model can be gradually modified in two dimensions according to the actual printing model, making the perforated structure looser as the model height increases, further reducing material consumption. While maintaining the original support effect, a shelling technique can be used to process the solid parts of the hollow structure model, transforming it into a hollow support, further reducing material usage and minimizing waste. Attached Figure Description

[0031] Figure 1 This is a flowchart of the steps of the present invention.

[0032] Figure 2 This is a schematic diagram illustrating the implementation process of the present invention.

[0033] Figure 3 This is a schematic diagram of the structure of the first support of the present invention.

[0034] Figure 4 This is a schematic diagram of the hollow structure model of the present invention.

[0035] Figure 5 This is a schematic diagram of the third support structure of the present invention.

[0036] In the picture:

[0037] 1-First support, 11-Top surface of the first support, 2-Second support, 3-Third support, 4-Gradual non-contact support surface, 5-Hollow structure model, 6-Supported model. Detailed Implementation

[0038] The present invention will now be described in further detail.

[0039] like Figures 1-3 As shown, a method for fabricating a printed model based on gradient offset non-contact support includes the following steps:

[0040] Step 1: Import the supported model 6 into the planar data processing software Materialise Magics, and adjust the model's angle, position, and size;

[0041] Select the volumetric support function in the support generation function of Materialise Magics software, and adjust the Z-axis offset; obtain a non-contact block support with a single offset, and save it as an STL format, denoted as the first support 1;

[0042] Step 2: Import the first support 1 into Rhino software, use Grasshopper to identify the top surface 11 of the first support and all minimum points. Using the Z coordinate of the minimum point of the top surface 11 of the first support as the reference, subtract the Z coordinate value of all points on the top surface 11 of the first support from the Z coordinate value of the minimum point with the smallest distance to obtain a series of height differences, denoted as Δh.

[0043] Step 3: Using the formula Znew=Z+kΔh, calculate all Z coordinate values ​​Znew based on the Z coordinate values ​​of all points on the top surface 11 of the first support, the height difference Δh, and the gradual support ratio coefficient k, and obtain the corresponding proportion of the gradual non-contact support surface 4. There is a gradual gap layer between the gradual non-contact support surface 4 and the supported model 6.

[0044] Step 4: Perform an AND operation between the gradient non-contact support surface 4 and the first support 1 to obtain the gradient non-contact second support 2;

[0045] Step 5: Combine the second support 2 with the supported model 6 and import them into the 3D photopolymer printer. Prepare the slurry according to the specific usage requirements of the supported model 6. Use the slurry to print the solid supported model 6 and the second support 2 layer by layer, as well as the gradient gap layer between the supported model 6 and the second support 2 to maintain the slurry morphology, thereby obtaining a printed model based on gradient offset non-contact support. Separate the printed model from the non-contact volume support, and then clean, dry, degrease, and sinter the printed model to finally obtain a printed model without support marks.

[0046] This invention optimizes the structure of existing non-contact supports by creatively proposing a method of using gradient offset non-contact supports to replace the original support method. Compared with the original non-contact supports, the gradient offset non-contact supports adjust the distance between the non-contact supports and the supported model 6. By utilizing the height difference between the minimum height of the bottom surface of the supported model 6 and the top surface of the non-contact supports, and substituting it into the corresponding coordinate transformation formula, the gap layer changes with the height difference between the minimum height of the supported surface and the top surface of the supports. Different gradient non-contact supports can be obtained according to different supported models 6. This design method is applicable to adding most non-contact supports, thereby enabling the non-contact supports to gradually change, making the supports less likely to stick to the supported model 6, reducing the difficulty of separation, and ensuring the integrity of the supported model 6 to the greatest extent.

[0047] Meanwhile, based on the original solid second support 2, a regular perforated structure was introduced through logical operations, making the second support 2 no longer a solid body, thereby reducing material usage. Specifically, this includes the following steps:

[0048] like Figure 2 , Figure 4 , Figure 5 As shown, before printing, the hollow structure model 5, preferably the hollow "well" shaped model, is imported into Rhino software, and the size of the "well" shaped model and its positional relationship with the second support 2 are adjusted.

[0049] The hollow structure model 5 can achieve a two-dimensional gradient of the hollowed-out portion based on the characteristics of the model's outer contour. Specifically, the hollow structure model 5 includes multiple parallel vertical holes and multiple parallel horizontal holes. The diameter of the vertical holes remains constant from top to bottom, while the diameter of the horizontal holes gradually decreases from top to bottom. The specific structural type and the size of the regular holes in the hollow structure model 5 can be determined by the supported model 6.

[0050] The second support 2 is subjected to a Boolean operation with the "grid" model, retaining the portion where the second support 2 intersects with the hollow structure model 5, resulting in a gradient non-contact support with a smaller contact area. This is exported as an STL file and designated as the third support 3. The third support 3 is then combined with the supported model 6 and imported into a 3D stereolithography printer for printing. Using this structure, the support stability of the supported model 6 is ensured, while the contact area between the supported model 6 and the non-contact support is smaller, making it easier for the support to separate from the model after printing.

[0051] To further reduce the amount of material used, the solid part of the hollow structure model 5 can be appropriately shelled according to the actual support requirements of the supported model 6 to form a hollow support part.

[0052] A printed model based on gradient offset non-contact support is disclosed, which is prepared using a method for fabricating a printed model based on gradient offset non-contact support. Because the non-contact support is gradually changed, the support is less likely to adhere to the supported model 6, reducing the difficulty of separation and maximizing the integrity of the supported model 6.

[0053] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for fabricating a printed model based on gradient offset non-contact support, characterized in that: Includes the following steps, Step 1: Import the model to be supported into the software, use the volumetric support function in the software's support generation function to adjust the Z-axis offset of the model to obtain the first support with a single offset. Step 2: Use software to identify the top surface of the first support and all the minimum points on the top surface. Using the Z coordinate of the minimum point on the top surface of the first support as a reference, subtract the Z coordinate value of all points on the top surface of the first support from the Z coordinate value of the minimum point with the smallest distance to obtain a series of height differences, denoted as Δh. Step 3: Using the formula Znew=Z+kΔh, calculate all Z coordinate values ​​Znew based on the Z coordinate values ​​of all points on the top surface of the first support, the height difference Δh, and the gradual support ratio coefficient k, to obtain the corresponding proportion of the gradual non-contact support surface. There is a gradual gap layer between the gradual non-contact support surface and the supported model. Step 4: Perform a bitwise AND operation between the gradient non-contact support surface and the first support to obtain the gradient non-contact second support; Step 5: Combine the second support and the supported model and import them into the 3D photopolymerization printer. Use the paste to print the solid supported model and the second support layer by layer, as well as the gradient gap layer between the supported model and the second support to maintain the paste shape, thereby obtaining a printed model based on the gradient offset non-contact support.

2. The method for preparing a printed model based on a gradient offset non-contact support according to claim 1, characterized in that: Before printing, a Boolean operation is performed between the second support and the hollow structure model in the software to obtain a third support with an array of holes.

3. The method for preparing a printed model based on a non-contact support with gradient offset according to claim 2, characterized in that: The hollow structure model includes multiple parallel vertical holes and multiple parallel horizontal holes. The diameter of the vertical holes remains constant from top to bottom, while the diameter of the horizontal holes gradually decreases from top to bottom.

4. The method for preparing a printed model based on a non-contact support with a gradient offset according to claim 3, characterized in that: The shelling technique is used to process the solid parts of the hollow structure model, turning them into hollow supports.

5. The method for preparing a printed model based on a non-contact support with gradient offset according to claim 1, characterized in that: The gradient gap layer is printed using a high-viscosity material.

6. The method for preparing a printed model based on a gradient offset non-contact support according to claim 5, characterized in that: High-viscosity materials are photosensitive materials.

7. The method for preparing a printed model based on a gradient offset non-contact support according to claim 6, characterized in that: The viscosity of the photosensitive material ranges from 50 Pa·s to 100 Pa·s.

8. The method for preparing a printed model based on a non-contact support with gradient offset according to claim 1, characterized in that: The height of the gradient gap layer is 1.5-4 times the depth of the photopolymerization process.

9. The method for preparing a printed model based on a gradient offset non-contact support according to claim 1, characterized in that: The supported model and the second support use the same or different printing parameters.

10. A printed model based on gradient offset non-contact support, characterized in that: The printed model was prepared using the method for preparing a non-contact support based on gradient offset as described in any one of claims 1-9.

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