Contour offset-based laser powder bed fusion printing method and component
By using a contour offset printing method and a secondary remelting process, the problem of poor contour edge consistency in the forming of Ti6Al4V parts using laser powder bed melting technology has been solved, achieving high-precision and high-gloss forming results, which are suitable for the manufacturing of complex structures such as medical eyeglass frames.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XI AN JIAOTONG UNIV
- Filing Date
- 2026-01-30
- Publication Date
- 2026-04-28
Smart Images
Figure CN121928078A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of 3D printing technology, specifically relating to a laser powder bed fusion printing method and component based on contour offset. Background Technology
[0002] Laser powder bed melting (LPBF), a branch of metal additive manufacturing, uses high-energy lasers to selectively melt metal powder layer by layer, enabling the direct fabrication of complex geometric structures that are difficult to achieve with traditional subtractive processing. This technology has demonstrated advantages in aerospace, biomedicine, and other fields, particularly suitable for the personalized, small-batch manufacturing of precision components from difficult-to-machine Ti6Al4V titanium alloys. For example, in the production of personalized medical devices such as customized medical eyeglass frames, LPBF technology can integrally form frames and temples with complex curved surfaces and thin structures, avoiding multi-part assembly and better matching the user's facial anatomy. However, when applying LPBF technology to precision parts such as medical eyeglass frames, which have higher requirements for dimensional accuracy and surface finish, the forming quality still faces shortcomings. These parts typically have fine contour features, thin-walled structures, and complex free-form surfaces, and their final dimensions and surface condition directly affect wearing comfort.
[0003] Currently, in the LPBF forming process of Ti6Al4V parts, a single laser scanning strategy is typically adopted for the component contour area to improve efficiency. However, this strategy has inherent limitations in practical applications: the energy input, molten pool dynamics, and solidification behavior of a single contour scan are difficult to maintain optimally on complex paths, easily leading to poor forming consistency of the contour edges. Specifically, this manifests as molten pool overflow or spheroidization caused by excessive local energy on the contour scanning trajectory, or incomplete powder fusion and adhesion due to insufficient energy. These microscopic defects accumulate macroscopically as contour size fluctuations, high edge roughness, and visible deviations between the contour geometry and the design model. For medical eyeglass frames, the roughness and dimensional inaccuracies of the contour edges directly affect their visual effect, tactile feel, and assembly accuracy with the lenses. Although optimizing overall process parameters, such as laser power and scanning speed, can improve these problems to some extent, a single fixed contour scanning parameter is difficult to adapt to the forming requirements of contours in different positions and directions, especially as the thermal accumulation state changes throughout the part forming process, making it difficult to maintain stable contour quality. Summary of the Invention
[0004] To address the problems existing in the prior art, this invention provides a laser powder bed fusion printing method and component based on contour offset. Its purpose is to overcome the inherent process limitations of single contour scanning by improving the scanning strategy of the contour region, thereby improving the dimensional accuracy, geometric shape reproduction and surface quality of the contour edge of Ti6Al4V metal components.
[0005] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: According to a first aspect of the present invention, a laser powder bed fusion printing method based on contour offset is provided, comprising: Ti6Al4V alloy powder is available; A powder layer is deposited on the substrate; Based on the contour information obtained from 3D model slices, the laser beam is controlled to scan and melt the powder along a preset path to form components layer by layer. Specifically, when printing the contour area of each layer, a contour offset printing operation is performed: inside the contour, according to a predetermined offset distance and a predetermined offset power, a circle of inner offset contour is first scanned and melted, and then the contour itself is scanned and melted.
[0006] In one possible implementation of the first aspect, the predetermined offset distance ranges from 0.04 mm to 0.07 mm.
[0007] In one possible implementation of the first aspect, the predetermined bias power ranges from 210W to 240W.
[0008] In one possible implementation of the first aspect, the scanning speed used when scanning and melting an inner offset profile is 900 mm / s to 1200 mm / s.
[0009] In one possible implementation of the first aspect, when scanning and melting the contour itself, a laser power of 180W to 200W is used, and a scanning speed of 900mm / s to 1200mm / s is employed.
[0010] In one possible implementation of the first aspect, the thickness of the powder layer is 0.03 mm to 0.05 mm.
[0011] In one possible implementation of the first aspect, the predetermined bias distance is 0.07 mm and the predetermined bias power is 220 W.
[0012] In one possible implementation of the first aspect, a scanning speed of 900 mm / s is used when scanning to melt an inner offset profile.
[0013] In one possible implementation of the first aspect, the component is a medical eyeglass frame.
[0014] According to a second aspect of the present invention, a Ti6Al4V titanium alloy component manufactured by the printing method is provided, the component being a medical eyeglass frame.
[0015] Compared with the prior art, the present invention has at least the following beneficial effects: This invention proposes a laser powder bed fusion printing method based on contour offset. By introducing a contour offset strategy and combining it with a secondary remelting process, the surface quality and dimensional accuracy of the formed parts are improved. Specifically, the core principle of this method lies in the significant difference in the absorption rate of laser energy between metal powder and solidified metal. During the initial scanning and melting process, the molten pool is in a dynamic flow state, and its strong internal convection effect easily adsorbs surrounding unmelted powder to the edge of the molten pool, resulting in excess powder adhering to the workpiece contour after solidification, forming rough or irregular edges. To solve the above problems, this invention performs a secondary laser remelting process on the offset contour area after the initial offset contour forming. By precisely controlling the laser power, scanning speed, and offset distance, the solidified edge area is selectively remelted, while avoiding direct action on the surrounding loose powder. This process not only effectively eliminates edge defects and powder adhesion caused by the initial offset forming, but also optimizes the local energy distribution and suppresses the adsorption effect caused by molten pool convection, thereby obtaining a more regular and stable molten pool morphology. Ultimately, this technology can simultaneously improve the surface roughness and geometric accuracy of the printed parts. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0017] Figure 1 The test width of different parts of the eyeglass frame under a 0.04mm offset in Example 1; Figure 2 This is a comparison of the measured roughness values of white light interferometry with and without bias in Example 1. Figure 3 The test width of different parts of the eyeglass frame under a 0.07mm offset in Example 2; Figure 4 This is a comparison of the measured roughness values of white light interferometry with and without bias in Example 2. Figure 5 The test width of different parts of the eyeglass frame under a 0.05mm offset in Example 3; Figure 6 This is a comparison of the measured roughness values of white light interferometry with and without bias in Example 3; Figure 7 The test width of different parts of the eyeglass frame under a 0.04mm offset in Example 4; Figure 8 This is a photograph of the eyeglass frame printed under the conditions of Example 1. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0019] Example 1 This embodiment provides a method for laser powder bed fusion printing of Ti6Al4V medical eyeglass frames based on contour offset. The specific process is as follows: Spherical Ti6Al4V alloy powder with a particle size distribution of 15-53 μm was prepared. First, the 3D CAD model of the target component was sliced, with a slice thickness set to 0.03 mm. The slicing software generated the contour scan path and internal filling scan path for each layer.
[0020] During printing, Ti6Al4V alloy powder is deposited on the substrate to form a powder layer of uniform thickness. For the contour area of the component, the contour offset printing strategy of this invention is adopted. Specifically, for each outer contour of each layer, the laser beam is controlled to perform a two-step scanning operation: First, at a distance of 0.04mm from the inner side of the design contour line, a circle of inner offset contour is scanned and melted at a laser power of 210W and a scanning speed of 1000mm / s; Second, immediately following the design contour line itself, the final component contour is scanned and melted at a laser power of 190W and a scanning speed of 1000mm / s.
[0021] For the internal filling area excluding the contour area, a conventional energy input strategy is used for scanning and melting. The specific parameters in this embodiment are: laser power 200W, scanning speed 1000mm / s, and scanning spacing 0.07mm.
[0022] Print layer by layer according to the above parameters, and finally obtain Ti6Al4V medical eyeglass frame.
[0023] Comparative Example 1 This comparative example was printed using a traditional single-scan contour strategy to contrast with Example 1.
[0024] The same Ti6Al4V powder and printing equipment were used as in Example 1. The slice layer thickness was also 0.03 mm, and the internal filling parameters were exactly the same. The only difference was the scanning strategy for the contour area: for each layer's contour, only one scan operation was performed, i.e., scanning directly along the designed contour line at a laser power of 190 W and a scanning speed of 1000 mm / s. The printed components had an internal density comparable to that of Example 1.
[0025] It should be noted that Comparative Example 1 shows the optimal printing result under the condition of no bias.
[0026] Combination Figure 1 and Figure 2 The test results show that the deviation between the outline dimensions of the medical eyeglass frame formed in this embodiment and the design model is effectively controlled within 0.3mm, and the average surface roughness Ra value of the outline edge is 7.31μm, demonstrating excellent forming accuracy and surface quality. Specifically, Figure 1 The design baseline of a theoretical width of 2mm is clearly shown, with the orange dashed line representing the theoretical value and the yellow bars presenting the measured width of the 3D-printed eyeglass frame at various locations without the contour offset technique (i.e., Comparative Example 1). Comparative analysis shows that the measured width of Comparative Example 1 deviates significantly from the theoretical value at multiple locations, with deviations ranging from approximately 0.45 to 0.5mm, indicating a significant deficiency in dimensional accuracy control with traditional single-scan contour scanning technology. In contrast, Example 1 (using a 0.04mm distance offset technique), represented by the green bars, demonstrates a significant advantage, effectively reducing the deviation between its measured width and the theoretical value to within 0.3mm, verifying the effectiveness of the contour offset technique in improving dimensional accuracy. Furthermore, the surface roughness of Example 1 and Comparative Example 1 was measured using a white light interferometer. The results show that the surface roughness Ra value of Example 1 is 7.31μm, while that of Comparative Example 1 is as high as 17.28μm. This significant difference fully demonstrates that traditional single-scan contour scanning processes suffer from instability in liquid phase flow and laser power fluctuations during powder melting, resulting in the final workpiece's dimensional accuracy and surface quality failing to meet high-precision requirements. In contrast, the offset remelting technology employed in this invention effectively reduces the impact of liquid phase flow on the workpiece surface by optimizing energy distribution and molten pool behavior, thereby achieving a simultaneous improvement in workpiece dimensional accuracy and surface quality.
[0027] Figure 8A physical sample of an eyeglass frame prepared according to Example 1 is shown. As can be seen from the figure, the overall structure of the frame is intact, without obvious warping or deformation. The lens rims on both sides are symmetrical and maintain a high degree of consistency, indicating good geometric stability during the forming process. The frame surface is smooth and uniform, without obvious layering, porosity, or cladding defects, demonstrating excellent printing quality. Combined with subsequent surface accuracy and roughness tests, the effectiveness of the process parameters in controlling forming accuracy and surface quality is further verified, fully demonstrating that the contour offset and secondary remelting strategy adopted in Example 1 is suitable for high-precision metal additive manufacturing and has good engineering application potential.
[0028] Example 2 The main difference between this embodiment and Embodiment 1 is that the offset distance of the inner offset contour, the laser power, and the scanning speed are adjusted.
[0029] In this embodiment, all basic process parameters are the same as in Example 1, including powder and layer thickness. The difference is that when performing the contour offset printing operation, the predetermined offset distance of the inner offset contour is adjusted to 0.07mm. That is, in the first step, scanning is performed at a distance of 0.07mm inside the design contour line with a laser power of 220W and a scanning speed of 900mm / s; in the second step, scanning is performed along the design contour line with a power of 190W and a speed of 900mm / s.
[0030] After forming, the component contour is inspected, combined with Figure 3 and Figure 4 The test results show that the component's outline dimensions are excellent, with deviations from the design model controlled within approximately 0.1 to 0.15 mm. Furthermore, the average surface roughness Ra value of the outline edges is 4.06 μm, demonstrating high-precision forming characteristics. (Detailed analysis follows.) Figure 3Data: The orange dashed line in the figure represents the theoretical value of the model, and the yellow bar chart shows the measured width of the 3D printed eyeglass frame at various positions without the contour offset technology (Comparative Example 1). The comparison shows that the measured width of Comparative Example 1 deviates significantly from the theoretical value at multiple positions, with deviations reaching approximately 0.45-0.5 mm, indicating limitations in dimensional control inherent in traditional single-scan contour scanning technology. In contrast, Example 2 (using a 0.07 mm distance offset technology), represented by the green bar chart, demonstrates a significant advantage, with the deviation between its measured width and the theoretical value effectively controlled within 0.15 mm, verifying the effectiveness of contour offset technology in improving dimensional accuracy. Further surface roughness measurements using a white light interferometer show that the Ra value of Example 2 is 4.06 μm, while the Ra value of Comparative Example 1 is as high as 17.28 μm. Similarly, this significant difference fully confirms that the instability of the liquid phase flow during powder melting and the fluctuation of laser power in traditional single-scan contour scanning technology make it difficult to meet high-precision requirements for workpiece surface quality and dimensional accuracy. In contrast, the offset remelting technology employed in this invention effectively reduces the impact of liquid phase flow on the workpiece surface by optimizing energy distribution and molten pool behavior, achieving simultaneous improvement in dimensional accuracy and surface quality. Experimental data further demonstrates the significant advantages of contour offset printing technology in improving component accuracy and roughness.
[0031] Example 3 The main difference between this embodiment and Embodiment 1 is that the layer thickness of the printed component has been adjusted.
[0032] In this embodiment, the printing layer thickness parameter is adjusted compared to that in Embodiment 1. The printing layer thickness in this embodiment is set to 0.05µm. Otherwise, the contour offset printing operation remains consistent with Embodiment 1, with the predetermined offset distance of the inner offset contour adjusted to 0.04mm. Specifically, in the first step, at a distance of 0.04mm from the inner side of the design contour line, a ring of inner offset contour is scanned and melted using a laser power of 210W and a scanning speed of 1000mm / s; in the second step, immediately following the design contour line itself, the final component contour is scanned and melted using a laser power of 190W and a scanning speed of 1000mm / s.
[0033] After forming, the component contour is inspected, combined with Figure 5 and Figure 6 The test results show that the component's contour dimensions are excellent, with deviations from the design model controlled within approximately 0.2 to 0.3 mm. Furthermore, the average surface roughness Ra value of the contour edges is 5.64 μm, demonstrating high-precision forming characteristics. This achievement verifies the stability of contour offset printing technology under different process conditions. Detailed analysis... Figure 5Data: The orange dashed line in the figure represents the theoretical value of the model, and the yellow bar chart shows the measured width of the 3D printed eyeglass frame at various locations without the contour offset technique (Comparative Example 1). The comparison shows that the measured width of Comparative Example 1 deviates significantly from the theoretical value at multiple locations, with deviations reaching approximately 0.45-0.5 mm. This indicates that the traditional single contour scanning process has significant limitations in dimensional control, especially with more significant fluctuations in accuracy when layer thickness changes. In contrast, Example 3, represented by the green bar chart, demonstrates a significant advantage, with the deviation between its measured width and the theoretical value effectively controlled within 0.3 mm, verifying the effectiveness of the contour offset technique in improving dimensional accuracy. It is noteworthy that this technique remains stable even when layer thickness parameters change, indicating that its resistance to process fluctuations is superior to traditional methods. Further surface roughness measurements using a white light interferometer show that the Ra value of Example 3 is 5.64 μm, while the Ra value of Comparative Example 1 is as high as 17.28 μm. This significant difference fully demonstrates that traditional single-scan contour scanning processes suffer from instability in liquid phase flow during powder melting and fluctuations in laser power, resulting in workpiece surface quality and dimensional accuracy that fail to meet high-precision requirements. In contrast, the offset remelting technology employed in this invention effectively reduces the impact of liquid phase flow on the workpiece surface by optimizing energy distribution and molten pool behavior, achieving simultaneous improvement in dimensional accuracy and surface quality. Experimental data further demonstrates the advantages of contour offset printing technology in improving component accuracy and roughness, particularly highlighting its unique advantage of maintaining process stability even with variations in layer thickness parameters.
[0034] Example 4 The main difference between this embodiment and Embodiment 1 is that the laser power and scanning speed have been adjusted.
[0035] In this embodiment, the offset distance and layer thickness are the same as in Embodiment 1. The difference is that during the printing operation, the predetermined offset distance of the inner offset contour is adjusted to 0.04mm. That is, in the first step, at a distance of 0.04mm from the inner side of the design contour line, a ring of inner offset contour is scanned and melted with a laser power of 240W and a scanning speed of 1000mm / s; in the second step, immediately following the design contour line itself, the final component contour is scanned and melted with a laser power of 180W and a scanning speed of 1000mm / s.
[0036] After forming, the component contour is inspected, combined with Figure 7 The test results show that the component's outline dimensions are excellent, with deviations from the design model controlled within approximately 0.2 to 0.3 mm. This achievement not only verifies the stability of the outline offset printing technology under different process conditions but also highlights its adaptability to laser power fluctuations. Detailed analysis... Figure 7Data: The orange dashed line in the figure represents the theoretical value of the model, and the yellow bars show the measured width of the 3D printed eyeglass frame at various locations without the contour offset technique (Comparative Example 1). The comparison shows that the measured width of Comparative Example 1 deviates significantly from the theoretical value at multiple locations, with deviations ranging from approximately 0.45 to 0.5 mm. This indicates that the traditional single-scan contour scanning process has significant limitations in dimensional control, especially when laser power fluctuates or layer thickness changes, resulting in a significant decrease in accuracy and stability. In contrast, Example 4 (using a 0.03 mm layer thickness and a 0.04 mm distance offset technique), represented by the green bars, demonstrates a significant advantage, with the deviation between the measured width and the theoretical value effectively controlled within 0.25 mm. It is noteworthy that the laser power in Example 4 was adjusted compared to Example 1, yet the dimensional accuracy remained stable. This result further verifies that the contour offset technique, by optimizing energy distribution, can effectively suppress the impact of laser power fluctuations on the molten pool behavior, thereby significantly improving the consistency of dimensional accuracy. Example 5 In this embodiment, a two-step scanning strategy is employed with a contour offset distance of 0.05 mm: First, an inner offset contour is formed by melting at 0.05 mm inside the designed contour line using a 210W laser power and a scanning speed of 1200 mm / s; then, immediately following the original designed contour line, a second scan is performed with the same laser power of 200W and a scanning speed of 1200 mm / s to complete the final component contour forming. This process improves forming accuracy, with the deviation between the actual component contour size and the design model controlled within the range of 0.25–0.30 mm, and the average edge surface roughness Ra reaching 7.44 μm, fully demonstrating excellent geometric fidelity and surface quality. The above results not only verify the effectiveness of the proposed contour offset printing method but also demonstrate its good stability and repeatability under different process windows, providing a reliable technical path for high-precision metal additive manufacturing.
[0037] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0038] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, 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 covered within the scope of protection of the present invention.
Claims
1. A laser powder bed fusion printing method based on contour offset, characterized in that, include: Ti6Al4V alloy powder is available; A powder layer is deposited on the substrate; Based on the contour information obtained from 3D model slices, the laser beam is controlled to scan and melt the powder along a preset path to form components layer by layer. Specifically, when printing the contour area of each layer, a contour offset printing operation is performed: inside the contour, according to a predetermined offset distance and a predetermined offset power, a circle of inner offset contour is first scanned and melted, and then the contour itself is scanned and melted.
2. The laser powder bed fusion printing method based on contour offset according to claim 1, characterized in that, The predetermined offset distance ranges from 0.04 mm to 0.07 mm.
3. The laser powder bed fusion printing method based on contour offset according to claim 1, characterized in that, The predetermined bias power ranges from 210W to 240W.
4. The laser powder bed fusion printing method based on contour offset according to claim 1, characterized in that, When scanning and melting an inner offset profile, a scanning speed of 900 mm / s to 1200 mm / s is used.
5. The laser powder bed fusion printing method based on contour offset according to claim 1, characterized in that, When scanning and melting the contour itself, a laser power of 180W to 200W is used, and a scanning speed of 900mm / s to 1200mm / s is employed.
6. The laser powder bed fusion printing method based on contour offset according to claim 1, characterized in that, The thickness of the powder layer is 0.03 mm to 0.05 mm.
7. The laser powder bed fusion printing method based on contour offset according to claim 1, characterized in that, The predetermined bias distance is 0.07mm, and the predetermined bias power is 220W.
8. The laser powder bed fusion printing method based on contour offset according to claim 7, characterized in that, When scanning and melting an inner offset profile, the scanning speed used is 900 mm / s.
9. The laser powder bed fusion printing method based on contour offset according to claim 1, characterized in that, The component is a medical eyeglass frame.
10. A Ti6Al4V titanium alloy component manufactured by the printing method according to any one of claims 1 to 9, characterized in that, The component is a medical eyeglass frame.