3D printing method and application of high-dimensional-precision metal product

Abstract

The invention discloses a 3D printing method and application of a high-dimensional-precision metal part. The invention belongs to the field of 3D printing. The invention aims to solve the technical problems that an existing 3D printing method is obvious in step effect, and in order to solve the problem, the preparation time and cost are increased, interlayer bonding is poor, residual stress is introduced, and workpieces in complex shapes cannot be formed in an existing solution mode. The method comprises the steps that firstly, three-dimensional modeling is conducted on a target component, and slicing processing is conducted; then metal to be formed is machined into a thin strip with a certain width-to-thickness ratio, then the thin strip serves as filling metal, and the angle between the filling metal and the substrate is set; and then wide-beam laser is selected for scanning, the angle of the laser and the substrate and the relative position of the laser and the filling metal are set, 3D printing parameters are set, and then 3D printing is conducted on the surface of the substrate according to slicing data. According to the method, the forming size precision of the workpiece is improved, and the method is suitable for complex-shape metal workpieces with high forming size precision.

Description

Technical Field

[0001] The present invention belongs to the field of 3D printing, and in particular relates to a 3D printing method and application of high-dimensional precision metal parts. Background Art

[0002] In the 3D printing process, since the material is deposited by layer-by-layer accumulation, the deposited layers have a certain thickness, which causes each adjacent deposited layer to be unable to completely fit the actual curved surface shape, thus forming steps on the surface, and the surface of the part will present a step-like texture. The existence of this step effect will have a significant impact on the surface roughness, dimensional accuracy, mechanical properties, fatigue properties and material yield of the formed parts. For surface roughness, the presence of steps makes the surface of the part no longer smooth and the roughness increases. The size of the roughness is related to factors such as layer thickness and printing process. Generally speaking, the thicker the layer, the higher the surface roughness. For dimensional accuracy, affected by the deposition method and thickness, when forming complex structures, the presence of steps will cause a deviation between the actual size and the designed size. This dimensional deviation may affect the assembly accuracy and functionality of the part. In terms of mechanical properties and fatigue properties, the steps may become stress concentration points, reducing the strength and fatigue life of the parts. Under stress, the stress will be concentrated at the steps, which can easily cause the parts to break or be damaged at the steps. In addition, in order to meet the actual engineering requirements of the parts, the dimensional deviation caused by the step effect needs to be machined and post-processed, which will cause material loss in the process and affect the material yield.

[0003] In order to improve the impact of the step effect in the 3D printing process, researchers have tried to optimize process parameters, post-processing, and material selection. In terms of optimizing process parameters, reducing the thickness of each layer to obtain a thinner layer thickness can better approximate the curved and inclined surfaces of the parts, improve the surface quality, and thus reduce the step effect. However, the reduction in the thickness of the deposited layer will increase manufacturing time and cost, and may also cause problems such as poor interlayer bonding. When performing post-machining processing for the step effect, machining the printed parts is a common method. Through milling, grinding and other processing methods, the steps on the surface of the parts can be removed, the surface flatness and dimensional accuracy can be improved, and the step effect can be reduced. However, machining may introduce residual stress and affect the performance of the parts. In addition, for some parts with complex shapes, machining may also have process difficulties. Summary of the invention

[0004] In order to overcome the defects of the above-mentioned prior art, the present invention provides a 3D printing method and application of metal parts with high dimensional accuracy.

[0005] One of the purposes of the present invention is to provide a 3D printing method for metal parts with high dimensional accuracy, which is carried out in the following steps:

[0006] S1: 3D modeling of the target component and slicing;

[0007] S2: Process the metal to be formed into a thin strip with a certain width-to-thickness ratio, then use it as filler metal, and set the angle between the filler metal and the substrate;

[0008] S3: Select a wide beam laser for scanning, set the angle between the laser and the substrate and the relative position to the filler metal, set the 3D printing parameters, and then perform 3D printing on the substrate surface according to the slice data.

[0009] It is further defined that the thin strip width to thickness ratio in S2 is 7-40, and the thickness is 0.2-1 mm.

[0010] It is further defined that the angle between the filling metal and the substrate normal in S2 is 70°-85°.

[0011] It is further defined that the width of the wide beam laser spot in S3 completely covers the thin strip.

[0012] It is further defined that the width of the light spot is 8-22 mm and the length is 1-2 mm. The width direction refers to the direction perpendicular to the printing direction.

[0013] It is further defined that the vertical distance between the end of the laser head and the filling metal in S3 is 16-22 mm.

[0014] It is further defined that in S3, the angle between the laser beam and the substrate normal is 6°-12°, the laser power is 1800W-3600W, the scanning speed is 2-10mm / s, the filling metal is in the same direction as the laser running, and the running speed is 0.5-6mm / s.

[0015] It is further defined that the inter-layer cooling time is 60-80s.

[0016] A second object of the present invention is to provide an application of the above method in forming complex-shaped metal parts with high dimensional accuracy.

[0017] It is further defined that the metal includes carbon steel, stainless steel, titanium alloys, magnesium alloys, aluminum alloys, and nickel-based alloys.

[0018] The third object of the present invention is to provide a metal part with high dimensional accuracy and complex shape obtained by the above application.

[0019] The advantages of the present invention compared to the prior art are:

[0020] (1) The present invention provides a wide-beam laser thin-strip metal additive manufacturing forming method, which utilizes the synergistic effect of wide-beam laser and thin-strip metal to effectively reduce the pressure difference at different positions in the molten pool. The smaller pressure difference will weaken the resistance of the liquid metal in the molten pool to the flow of the edge, which is conducive to the liquid metal to further flow to the edge of the molten pool, so that the molten pool can more easily expand its surface area, thereby significantly improving the spreadability of the molten pool in the additive manufacturing process.

[0021] (2) The temperature of the liquid metal at the edge of the molten pool in the present invention can be basically consistent with that of the core of the molten pool, which will significantly reduce the surface flow phenomenon caused by the change in surface tension caused by temperature, thereby reducing the overall fluctuation of the liquid metal in the molten pool, achieving more precise energy control and positioning accuracy of the molten pool, and the shape of the deposited layer obtained after the molten pool solidifies is more uniform and smooth, which greatly alleviates the step effect of the existing additive manufacturing method in the forming process, thereby significantly improving the dimensional combination accuracy between adjacent deposited layers, thereby improving the forming dimensional accuracy of the part, and greatly improving the restriction of surface roughness on the comprehensive performance of the part during the laser fuse or arc fuse additive manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a single-layer morphology image of the 5052 aluminum alloy prepared in Example 1 of the present invention;

[0023] Figure 2 The morphology and size distribution in the scanning direction of a single-layer workpiece of 5052 aluminum alloy prepared in Example 1 of the present invention;

[0024] Figure 3 The cross-sectional dimension curve of a single-layer workpiece of 5052 aluminum alloy prepared in Example 1 of the present invention;

[0025] Figure 4 This is a macroscopic photograph of a multilayer deposition product of 5052 aluminum alloy prepared in Example 1 of the present invention;

[0026] Figure 5 The morphology of the multilayer deposited product of 5052 aluminum alloy prepared in Example 1 of the present invention;

[0027] Figure 6 The side surface roughness result of the multilayer deposition product of 5052 aluminum alloy prepared in Example 1 of the present invention;

[0028] Figure 7 This is the line roughness result of the multilayer deposition product of 5052 aluminum alloy prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained through commercial channels by those skilled in the art.

[0031] The terms "comprising," "including," "having," "containing," or any other variations thereof, as used in the following examples, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus comprising the listed elements is not necessarily limited to only those elements, but may include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

[0032] The endpoints and any values ​​of the ranges disclosed in the invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this article.

[0033] Embodiment 1: The 3D printing method of high dimensional accuracy 5052 aluminum alloy in this embodiment is carried out according to the following steps:

[0034] (1) 3D modeling of the target component and slicing;

[0035] (2) Selecting a 5052 aluminum alloy plate with a size of 200 mm × 500 mm × 20 mm as a substrate, treating the substrate to remove the surface oxide layer, and fixing the substrate;

[0036] (3) 5052 aluminum alloy was processed into a thin strip with a width-to-thickness ratio of 10 (width 10 mm, thickness 1 mm), and then used as the filler metal, and the angle between the filler metal and the substrate normal was set to 85°;

[0037] (4) A wide beam laser with a laser size of 12 mm × 1 mm was selected for scanning, the angle between the laser beam and the substrate normal was set to 6°, and the vertical distance between the laser head and the thin strip filling metal was set to 16 mm;

[0038] (5) The laser power is 2800 W, and the scanning speed is 2 mm / s. The filling metal is in the same direction as the laser (scanning) and the running speed of the filling metal is 1 mm / s.

[0039] (6) The control system is set to stay for 400 ms after the laser is started, and the printing program is started after the molten pool is stable. Printing is performed under Ar gas protection, and the deposition of a single layer is completed after solidification;

[0040] (7) During the deposition process, the interlayer cooling time for each layer of deposition is 60 s, and the preparation of high-precision 5052 aluminum alloy is completed layer by layer.

[0041] The single-layer product of 5052 aluminum alloy prepared by the present invention is well formed, and the specific morphology is as follows Figure 1 As shown in the figure, the results show that the aspect ratio is 7.88 and the spreading angle of the single layer end is 22°. It can be seen that it shows obvious advantages in terms of aspect ratio and wetting angle. Figure 2 As shown in the figure, the edge of the deposited layer forms a good metallurgical bond and a gentle transition with the substrate, the deposited layer has uniform dimensions at different heights, and the formed surface is smooth. Figure 3 As shown in Figure 1, the cross-sectional size distribution of the single-layer deposition layer is uniform, and a smooth transition can be achieved from the bottom to the top. Figure 4 As shown, the appearance is Figure 5 As shown in the results, the dimensional accuracy is high and the step effect has been significantly improved. The surface roughness of the side of the multilayer deposition part is as follows Figure 6 As shown, after measurement, Ra = 0.487μm, the line roughness is as follows Figure 7 As shown in the figure, after measurement, Ra=2.5μm. It can be seen that it has obvious advantages in both step effect control and surface roughness improvement.

[0042] Comparative Example 1: The laser fuse additive manufacturing method is carried out according to the following steps:

[0043] (1) Select a 5052 aluminum alloy welding wire with a welding wire diameter of 1.2 mm, select a 5052 aluminum alloy plate with a size of 200 mm × 100 mm × 10 mm as a substrate, treat the substrate to remove the surface oxide layer, and fix the substrate;

[0044] (2) A laser beam with a spot radius of 0.45 mm was used as the heat source and the protective gas was Ar;

[0045] (3) The laser power is 3500 W, the scanning speed is 0.02 m / s, and the wire feeding speed is 2.5 m / min. The welding wire melts under the action of the laser to form a molten pool, and the single-layer deposition is completed after solidification;

[0046] (4) As the deposited layers gradually accumulate to form a multilayer component, the additive manufacturing of aluminum alloy is completed.

[0047] Table 1 Wetting angle and aspect ratio of comparative example 1 and embodiment 1

[0048]

[0049] The above are only preferred specific embodiments of the present invention, which are all different implementations based on the overall concept of the present invention, and the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A 3D printing method for high-dimensional precision metal parts, characterized in that: The method: S1: 3D modeling of the target component and slicing; S2: Process the metal to be formed into a thin strip with a certain width-to-thickness ratio, then use it as filler metal, and set the angle between the filler metal and the substrate; S3: Select a wide beam laser for scanning, set the angle between the laser and the substrate and the relative position to the filler metal, set the 3D printing parameters, and then perform 3D printing on the substrate surface according to the slice data.

2. The method according to claim 1, characterized in that: The thin strip in S2 has a width-to-thickness ratio of 7-40 and a thickness of 0.2-1 mm.

3. The method according to claim 1, characterized in that In S2, the angle between the filling metal and the substrate normal is 70°-85°.

4. The method according to claim 1, characterized in that: The width of the wide beam laser spot in S3 completely covers the thin strip.

5. The method according to claim 4, characterized in that The spot width is 8-22mm and the length is 1-2mm.

6. The method according to claim 1, characterized in that In S3, the vertical distance between the end of the laser head and the filler metal is 16-22 mm.

7. The method according to claim 1, characterized in that In S3, the angle between the laser beam and the substrate normal is 6°-12°, the laser power is 1800W-3600W, the scanning speed is 2-10mm / s, the filling metal is in the same direction as the laser, the running speed is 0.5-6mm / s, and the interlayer cooling time is 60-80s.

8. Application of the method according to any one of claims 1 to 8 in forming metal parts with complex shapes and high dimensional accuracy.

9. The use according to claim 8, characterized in that: Metals include carbon steel, stainless steel, titanium alloys, magnesium alloys, aluminum alloys and nickel-based alloys.

10. A metal product with complex shape and high dimensional accuracy obtained by the application of claim 8 or 9.

Images