Porous tin part and additive preparation method thereof

Abstract

The invention relates to the field of metal additive manufacturing, and provides a porous tin part and a novel additive manufacturing method thereof. The method comprises the following steps: S1, preparing pure tin powder by adopting a vacuum air fog technology, and screening to obtain tin powder with a set particle size; s2, three-dimensional modeling is conducted on the porous tin part to be prepared, the model is a compact model ignoring internal holes of the part, slicing analysis is conducted on the model, and data slices are obtained; s3, selective laser melting LPBF is used for printing layer by layer, and a porous structure is naturally formed in the printing process by optimizing the width of a molten pool and scanning line data; and S4, powder adhering to the surface of the part is removed, and the final porous tin part is obtained. The porous tin part is realized by utilizing unique physicochemical properties of tin and adjusting process parameters instead of model design. According to the method, the machining period is short, the porous tin part can be efficiently formed, and the highest LPBF structural resolution can be achieved.

Description

Technical Field

[0001] The invention relates to the field of metal additive manufacturing, and in particular to a porous tin part and an additive manufacturing method thereof. Background Art

[0002] Tin has excellent properties such as low melting point, soft texture, non-toxicity, corrosion resistance, and good ductility. It has shown broad application prospects in the fields of electronics, food processing, engineering machinery, biomedicine, aerospace, and energy storage. At present, the research on tin at home and abroad is mainly focused on copper-tin alloys, while the research on single tin is relatively lagging behind.

[0003] Laser powder bed fusion (LPBF) technology is currently the fastest growing and most promising technology in metal additive manufacturing. Using a high-energy laser beam as an energy source, the metal powder raw materials stacked layer by layer are selectively melted and solidified quickly. LPBF technology can directly form metal parts and achieve precise printing. At present, the preparation of tin and tin alloys by LPBF has become an efficient method for preparing tin.

[0004] LPBF preparation of tin and tin alloys plays an important role in industrial applications. However, with the advancement of science and technology, single-structure tin and tin alloys are difficult to meet the needs of industrial development. The preparation of porous tin parts has important applications in fields such as catalysis and engineering equipment.

[0005] Generally, model design is required to prepare porous parts by LPBF. However, LPBF printing has limitations. LPBF cannot form parts with model sizes smaller than the laser spot, and it is difficult to prepare smaller holes.

[0006] In view of this, the present invention develops a porous tin part and an additive manufacturing method thereof. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a porous tin part and an additive preparation method thereof, utilizing the physical and chemical properties of tin such as low melting point and low viscosity when melted, and by adjusting the molten pool width and scanning line spacing instead of using model design to achieve the preparation of a porous tin part.

[0008] The present invention adopts the following technical solution:

[0009] In one aspect, the present invention provides a method for additively preparing a porous tin part, comprising:

[0010] S1. Pure tin powder is prepared by vacuum atomization technology, and tin powder with a set particle size is obtained by sieving;

[0011] S2, performing three-dimensional modeling of the porous tin part to be prepared, wherein the model is a dense model ignoring the internal pores of the part, and performing slice analysis on the model to obtain data slices;

[0012] S3, slicing the data obtained in step S2, using selective laser melting (LPBF) to print layer by layer, and naturally forming a porous structure during the printing process by optimizing the molten pool width and scan line data to obtain a printed part;

[0013] S4, removing the powder sticking on the surface of the printed part to obtain the final porous tin part;

[0014] There is no order between steps S1 and S2.

[0015] Any possible implementation as described above further provides an implementation, in step S3, the optimized scanning line spacing is 250-400 μm, the scanning strategy is 90° scanning; the laser power is 60-70w, and the scanning speed is 400-800mm / s.

[0016] Any possible implementation as described above further provides an implementation, in which in step S2, the slice thickness is 30 μm.

[0017] Any possible implementation as described above further provides an implementation, in which in step S2, the slice data includes part scan line data and contour line data of each layer.

[0018] Any possible implementation as described above further provides an implementation, in which in step S3, the substrate used for LPBF printing is a low-density substrate to ensure metallurgical bonding between tin and the substrate.

[0019] Any possible implementation as described above further provides an implementation, wherein the low-density substrate is a titanium plate.

[0020] As any possible implementation described above, a further implementation is provided, in step S3, tin powder is placed in an LPBF device, and a protective atmosphere is introduced so that the oxygen content in the printing chamber is less than 200 ppm.

[0021] As any possible implementation described above, a further implementation is provided, where after step S4, the porous tin part is subjected to chemical and electrochemical treatment, and then subjected to ultrasonic oscillation treatment again in anhydrous ethanol.

[0022] By chemically and electrochemically treating porous tin parts, the size of the holes can be further increased while improving the surface roughness of the parts.

[0023] On the other hand, the present invention further provides a porous tin part, which is prepared by the above method.

[0024] The beneficial effects of the present invention are:

[0025] The present invention utilizes the unique physical and chemical properties of tin and realizes the preparation of a porous tin part by adjusting the scanning line spacing and the molten pool width instead of using model design. The present invention has a short processing cycle, can efficiently form porous tin parts, and can achieve the highest LPBF structural resolution. Within the parameter range, the minimum hole side length can reach 0.1mm and the maximum can reach 0.3mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Shown is a schematic flow chart of an additive manufacturing method for a porous tin part according to an embodiment of the present invention.

[0027] Figure 2 Shown is the porous tin part prepared in the example. DETAILED DESCRIPTION

[0028] The specific embodiments of the present invention will be described in detail below in conjunction with specific drawings. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered isolated, and they can be combined with each other to achieve better technical effects.

[0029] like Figure 1 As shown, an additive manufacturing method for a porous tin part according to an embodiment of the present invention comprises:

[0030] S1. Pure tin powder is prepared by vacuum atomization technology, and tin powder with a set particle size is obtained by sieving;

[0031] S2, performing three-dimensional modeling of the porous tin part to be prepared, wherein the model is a dense model ignoring the internal pores of the part, and performing slice analysis on the model to obtain data slices;

[0032] S3, slicing the data obtained in step S2, using selective laser melting (LPBF) to print layer by layer, and naturally forming a porous structure during the printing process by optimizing the molten pool width and scan line data to obtain a printed part;

[0033] S4, removing the powder sticking on the surface of the printed part to obtain the final porous tin part;

[0034] There is no order between steps S1 and S2.

[0035] In a specific embodiment, in step S3, the optimized scanning line spacing is 250-400 μm, the scanning strategy is 90° scanning, the laser power is 60-70w, and the scanning speed is 400-800mm / s. Only within this parameter range can qualified porous tin parts be prepared.

[0036] The effect of the above parameter optimization: laser power 60-70w, to ensure complete melting of the powder, while avoiding sample expansion caused by tin metal vapor during printing (which in turn reduces the strength of the finished product)

[0037] The scanning speed is 400-800mm / s. The scanning speed controls the molten pool width. The higher the scanning speed, the lower the single laser molten pool width. This can fully melt the powder while reducing the laser molten pool width to avoid overlapping between molten pools. When the scanning speed is not within this range, the printing of porous tin parts may fail due to the molten pool width being too large or too small.

[0038] The scanning line spacing is 250-400μm, and the scanning strategy is 90° scanning; the scanning line spacing and scanning strategy are necessary conditions for the natural generation of voids during the printing process. When the scanning line spacing is less than 250μm, the single-pass laser molten pools overlap each other and cannot naturally generate voids. When the scanning line spacing is higher than 400m, the distance between the molten pools is too large, which will damage the quality of the printed porous tin parts.

[0039] When the scanning strategy is not 90° scanning, the formation of holes cannot be controlled, which will also lead to the failure of printing porous tin parts.

[0040] In a specific embodiment, in step S1, the particle size of the tin powder after screening is 15-53 μm, and the powder particle size obeys the normal distribution; more than 90% of the powder particles are spherical or pear-shaped, and have good fluidity.

[0041] In a specific embodiment, in step S2, the slice thickness is 30 μm.

[0042] In a specific embodiment, in step S2, the slice data includes part scan line data and contour line data of each layer.

[0043] In a specific embodiment, in step S3, the substrate used for LPBF printing is a low-density substrate to ensure metallurgical bonding between tin and the substrate.

[0044] In a specific embodiment, the low-density substrate is a titanium plate.

[0045] In a specific embodiment, in step S3, tin powder is placed in an LPBF device, and a protective atmosphere is introduced so that the oxygen content in the printing chamber is less than 200 ppm.

[0046] In a specific embodiment, after step S4, the porous tin part is treated chemically and electrochemically, and then ultrasonically shaken again in anhydrous ethanol.

[0047] Example

[0048] A method for additive manufacturing of metallic tin comprises the following steps:

[0049] Step 1: clean the tin block and place it in a vacuum arc melting furnace or a vacuum induction furnace for melting, and use vacuum gas atomization to obtain pure tin powder; sieve to obtain tin powder with a particle size of 15-53μm, and the particle size obeys normal distribution; more than 90% of the powder particles are spherical or pear-shaped with good fluidity.

[0050] Step 2: Create and import a cube model. The model is a dense model that ignores the internal holes of the parts. Use slicing software to slice the model to obtain data slices. The slice layer thickness is 30μm. The data slices include the part scanning line data and contour line data of each layer; the scanning line spacing is 0.25μm, and the scanning strategy is 90° scanning.

[0051] Step 3: Place the tin powder into the LPBF device. After the powder is placed, introduce a protective atmosphere so that the oxygen content in the chamber is less than 200ppm.

[0052] Step 4: Use a titanium substrate for printing; use a laser power of 60W and a scanning speed of 800mm / s to perform powder laying and laser sintering layer by layer according to the slice data;

[0053] Step 5: After the printing is finished and cooled to room temperature, remove the substrate; cut the sample and further clean it with ultrasound to obtain a porous part of tin.

[0054] The prepared porous tin parts are as follows Figure 2 shown.

[0055] The present invention utilizes the unique physical and chemical properties of tin and realizes the porous preparation of tin parts by adjusting the scanning line spacing and the molten pool width instead of using model design. The present invention has a short processing cycle, can efficiently form porous tin parts, and can achieve the highest LPBF structural resolution. Within the parameter range, the minimum side length of the hole can reach 0.1mm and the maximum can reach 0.3mm.

[0056] Although several embodiments of the present invention have been given herein, those skilled in the art should understand that the embodiments of the present invention may be modified without departing from the spirit of the present invention. The above embodiments are merely exemplary and should not be used as a limitation on the scope of the present invention.

Claims

1. A method for additively preparing porous tin parts, characterized in that: The method comprises: S1. Pure tin powder is prepared by vacuum atomization technology, and tin powder with a set particle size is obtained by sieving; S2, performing three-dimensional modeling of the porous tin part to be prepared, wherein the model is a dense model ignoring the internal pores of the part, and performing slice analysis on the model to obtain data slices; S3, slicing the data obtained in step S2, using selective laser melting (LPBF) to print layer by layer, and naturally forming a porous structure during the printing process by optimizing the molten pool width and scan line data to obtain a printed part; S4, removing the powder sticking on the surface of the printed part to obtain the final porous tin part; There is no order between steps S1 and S2.

2. The additive manufacturing method for porous tin parts according to claim 1, characterized in that: In step S3, the optimized scanning line spacing is 250-400 μm, the scanning strategy is 90° scanning, the laser power is 60-70 W, and the scanning speed is 400-800 mm / s.

3. The additive manufacturing method for porous tin parts according to claim 1, characterized in that: In step S1, the particle size of the tin powder after screening is 15-53 μm, and the powder particle size obeys the normal distribution; more than 90% of the powder particles are spherical or pear-shaped.

4. The additive manufacturing method for porous tin parts according to claim 1, characterized in that: In step S2, the slice thickness is 30 μm.

5. The additive manufacturing method for porous tin parts according to claim 1, characterized in that: In step S2, the data slices include part scan line data and contour line data of each layer.

6. The additive manufacturing method for porous tin parts according to claim 1, characterized in that: In step S3, the substrate used for selective laser melting LPBF printing is a low-density substrate to ensure metallurgical bonding between tin and the substrate.

7. The additive manufacturing method for porous tin parts according to claim 6, characterized in that: The low-density substrate is a titanium plate.

8. The additive manufacturing method for porous tin parts according to claim 1, characterized in that: In step S3, tin powder is placed in a selective laser melting (LPBF) device, and a protective atmosphere is introduced to make the oxygen content in the printing chamber less than 200 ppm.

9. The additive manufacturing method for porous tin parts according to claim 1, characterized in that: After step S4, the porous tin part is treated chemically and electrochemically, and then ultrasonically shaken again in anhydrous ethanol.

10. A porous tin part, characterized in that: The porous tin part is prepared by the method according to any one of claims 1-9.

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