A method for manufacturing a bionic smart fastener based on laser directed energy deposition

Abstract

The application discloses a method for manufacturing a bionic smart fastener based on laser directional energy deposition, and relates to the technical field of additive manufacturing, and comprises the following steps: step one: constructing a fastener and printing layered profile data and deposition working routes of a corresponding parameter buckle structure; step two: printing an overall structure of the fastener according to the printed layered profile data and the deposition working routes of the buckle structure generated in step one and according to set printing parameters; step three: constructing printing layered profile data and deposition working routes of a NiTiCu super-elastic material smart coating; step four: printing a layer of the NiTiCu super-elastic material smart coating with a specific thickness on a working surface of the overall structure of the fastener and a side surface of a head of the fastener according to set printing parameters through a directional energy deposition technology; and step five: processing a pit array according to set non-smooth structure parameters for the overall structure of the fastener with the NiTiCu super-elastic material smart coating processed in step four.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, and in particular to a method for manufacturing biomimetic smart fasteners based on laser-directed energy deposition. Background Technology

[0002] With the rapid development of global industry and the ever-increasing scale of construction, fasteners have always played a crucial role in the construction of various buildings and industrial machinery. Fasteners are mechanical parts that connect two or more mechanical components, making them a unified whole. Fasteners are a class of mechanical parts with an extremely wide range of applications and an enormous quantity used. Various types of fasteners can be found in all kinds of machinery, transportation vehicles, basic building infrastructure, tools, and instruments. Due to the vast range of applications and the important role they play, the processing requirements and manufacturing quality control of fasteners are extremely stringent.

[0003] However, with the continuous development of advanced technologies and the increasing demands of scientific exploration, mechanical structures are becoming increasingly complex, and their service environments are becoming increasingly harsh. Fasteners, as a fundamental and crucial component, are also facing increasingly complex service environments. Traditional fasteners, under the influence of high-intensity loads in special environments such as the deep sea, space, and high radiation, experience a significant decrease in service life, and their fastening strength often fails to meet requirements. Through millions of years of evolution, nature has optimized and developed adaptive and self-adjusting friction-increasing structures. Among these, the barbed structure, which adjusts resistance through its own elasticity, provides a feasible solution for intelligent adjustment of fasteners, significantly improving their fastening performance. Simultaneously, with the research on biomimetic coatings, fasteners with biomimetic coatings and structures are expected to adapt to loads in different special environments, achieving intelligent fastening. Summary of the Invention

[0004] To address the problem of decreased fastening strength of existing fasteners in special environments such as aerospace, deep-sea exploration, and high-radiation environments, this invention proposes a method for manufacturing biomimetic smart fasteners based on laser-directed energy deposition.

[0005] A method for manufacturing biomimetic smart fasteners based on laser-directed energy deposition includes the following steps:

[0006] Step 1: Construct the fastener and corresponding parameters of the snap-fit ​​structure, print the layered contour data and deposition path;

[0007] Step 2: Based on the snap-fit ​​structure printing layer contour data and deposition path generated in Step 1, NiTiNb superelastic powder material is delivered in real time through laser powder bed melting technology, and the overall structure of the fastener is printed according to the set printing parameters, thereby obtaining the overall structure of the fastener.

[0008] Step 3: Construct the printing layer profile data and deposition workflow for the NiTiCu superelastic material smart coating;

[0009] Step 4: Based on the printing layer contour data and deposition path of the NiTiCu superelastic material smart coating generated in Step 3, a layer of NiTiCu superelastic material smart coating of a specific thickness is printed on the working surface of the overall fastener structure and the side of the fastener head according to the set printing parameters using directional energy deposition technology.

[0010] Step 5: The fastener structure with NiTiCu superelastic material smart coating processed in Step 4 is processed according to the set non-smooth structure parameters. A pit array is sintered on the NiTiCu superelastic material smart coating on each side of the fastener head using directional energy deposition technology.

[0011] Preferably, the snap-fit ​​structure with the corresponding parameters in step one is as follows: the length of the snap-fit ​​structure should be less than or equal to one-sixth of the outer diameter of the fastener thread; on the smooth section a of the fastener, along its axial direction, the interval between two adjacent snap-fit ​​structures is the length of one snap-fit ​​structure; the angle between two adjacent snap-fit ​​structures on the same circumferential surface of the smooth section a of the fastener is 90°; the working direction of the snap-fit ​​structure on the smooth section a of the fastener extends along the axial direction of the fastener towards the head of the fastener; on the threaded section b of the fastener, snap-fit ​​structures are arranged starting from the second-level thread; the angle between two snap-fit ​​structures arranged opposite each other on the same-level thread is 180°; the snap-fit ​​structures on adjacent levels of threads are arranged in a 90° staggered pattern; the working direction of the snap-fit ​​structure on the threaded section b is consistent with the thread direction.

[0012] The snap-fit ​​structure is a snap-fit ​​structure with a U-shaped cavity.

[0013] Preferably, in step two, the printing parameters are: laser spot diameter 1-3mm, laser power 400-600W, and scanning speed 200-400mm / min.

[0014] Preferably, the detailed method for printing a NiTiCu superelastic material smart coating of a specific thickness on the working surface of the overall structure of the fastener and the side of the fastener head using directional energy deposition technology in step four is as follows:

[0015] The fastener's overall structure is held horizontally by a clamp, which rotates uniformly around the central axis of the fastener's overall structure. The rotation speed should be calculated based on the diameter of the fastener's overall structure and the scanning speed. It is also necessary to ensure that the NiTiCu superelastic material intelligent coating is printed uniformly along the axial direction of the fastener's overall structure. When printing reaches the snap-fit ​​structure, the laser needs to be paused to ensure that there is no NiTiCu superelastic material intelligent coating on the back of the snap-fit ​​structure.

[0016] Preferably, in step four, the thickness of the NiTiCu superelastic material smart coating of a specific thickness should be less than one-sixth of the outer diameter of the fastener thread.

[0017] Preferably, the printing parameters in step four are: spot diameter 1-3mm, laser power 400-600W, scanning speed 200-400mm / min, powder feeding rate 10-30g / min, protective gas flow rate 8-12L / min, and powder carrier gas flow rate 8-13L / min.

[0018] Preferably, in step five, the overall structure of the fastener with the NiTiCu superelastic material smart coating is horizontally clamped by a jig. The jig rotates around the central axis of the overall structure of the fastener with the NiTiCu superelastic material smart coating. After processing each fastener head side, the laser processing is stopped, the jig rotates so that the next fastener head side faces upward, and the processing of the next side continues until all processing is completed.

[0019] Preferably, in step five, the non-smooth structure parameters are: the diameter of each pit structure is 1mm, the depth of each pit structure is 0.5-1mm, and the spacing between two adjacent pit structures is 1mm.

[0020] The beneficial effects of this invention are:

[0021] The biomimetic smart fasteners printed using the printing parameters and printing materials described in this application have excellent elasticity and can overcome the problem of service fatigue to a certain extent.

[0022] The NiTiCu superelastic material smart coating has sensitive elastic properties. When the external load is within the normal range, the NiTiCu superelastic material smart coating has small strain, and the overall structure fit of the biomimetic smart fastener is moderate. When a large external load is applied, it can quickly generate strain, and the stress of the NiTiCu superelastic material smart coating increases in a short time. The fit of the biomimetic smart fastener increases rapidly to meet the fastening requirements in special environments. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A side view of the biomimetic smart fastener prepared according to the present invention;

[0025] Figure 2 yes Figure 1Cross-sectional view at point AA;

[0026] Figure 3 yes Figure 1 Cross-sectional view at point BB;

[0027] Figure 4 This is a side view of the fixture holding the biomimetic smart fastener;

[0028] Figure 5 This is a biomimetic schematic diagram of a snap-fit ​​structure. Detailed Implementation

[0029] To make the objectives, processing design schemes, and advantages of the embodiments of this application clearer, the design schemes and manufacturing methods of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0030] like Figures 1 to 5 As shown, a method for manufacturing biomimetic smart fasteners based on laser-directed energy deposition includes the following steps:

[0031] Step 1: Construct the fastener and corresponding parameters of the snap-fit ​​structure, print the layered contour data and deposition path;

[0032] Step 2: Based on the snap-fit ​​structure printing layer contour data and deposition path generated in Step 1, NiTiNb superelastic powder material is delivered in real time through laser powder bed melting technology, and the overall structure of the fastener is printed according to the set printing parameters, thereby obtaining the overall structure of the fastener.

[0033] Step 3: Construct the printing layer profile data and deposition workflow for the NiTiCu superelastic material smart coating;

[0034] Step 4: Based on the printing layer contour data and deposition path of the NiTiCu superelastic material smart coating generated in Step 3, a layer of NiTiCu superelastic material smart coating of a specific thickness is printed on the working surface of the overall fastener structure and the side of the fastener head according to the set printing parameters using directional energy deposition technology.

[0035] Step 5: The overall structure of the fastener with the NiTiCu superelastic material smart coating processed in Step 4 is processed according to the set non-smooth structure parameters. A pit array is sintered on the NiTiCu superelastic material smart coating on each side of the fastener head using directional energy deposition technology, thereby reducing the self-loosening of the bionic smart fastener caused by working friction.

[0036] Furthermore, the snap-fit ​​structure for the corresponding parameters in step one is as follows: the length of the snap-fit ​​structure is limited to between 3-9mm. The specific length needs to be adjusted according to the thickness of the NiTiCu superelastic material's intelligent coating and the size of the fastener design. In principle, the length of the snap-fit ​​structure should be less than or equal to one-sixth of the outer diameter of the fastener thread; for example... Figure 1 As shown, in the smooth section a of the fastener, along its axial direction, the interval between two adjacent snap-fit ​​structures is the length of one snap-fit ​​structure. The angle between two adjacent snap-fit ​​structures on the same circumferential surface of the smooth section a is 90°. The working direction of the snap-fit ​​structures on the smooth section a extends along the axial direction of the fastener towards the head of the fastener. In the threaded section b of the fastener, snap-fit ​​structures are arranged starting from the second-level thread. The angle between two snap-fit ​​structures arranged opposite each other on the same level of thread is 180°. The snap-fit ​​structures on adjacent levels of thread are arranged at 90° angles. The working direction of the snap-fit ​​structures on the threaded section b is consistent with the thread direction; that is, the inclination direction of the snap-fit ​​structure is always opposite to the working direction of the fastener.

[0037] The aforementioned snap-fit ​​structure is designed based on the filiform papillae structure of the tongue of felines. The snap-fit ​​structure is a U-shaped cavity, and the root of the snap-fit ​​structure is covered by a NiTiCu superelastic material smart coating.

[0038] Furthermore, in step two, the printing parameters are: laser spot diameter 1-3mm, laser power 400-600W, and scanning speed 200-400mm / min.

[0039] Furthermore, in step four, the detailed method for printing a NiTiCu superelastic material smart coating of a specific thickness on the working surface of the overall fastener structure and the side of the fastener head using directional energy deposition technology is as follows:

[0040] The fastener's overall structure is held horizontally by a fixture, which rotates uniformly around the central axis of the fastener's overall structure. The rotation speed should be calculated based on the diameter of the fastener's overall structure and the scanning speed, ensuring that the NiTiCu superelastic material intelligent coating is printed uniformly along the axial direction of the fastener's overall structure. When printing reaches the snap-fit ​​structure, the laser needs to be paused to ensure that there is no NiTiCu superelastic material intelligent coating on the back of the snap-fit ​​structure. It should be noted that the grooves inevitably formed during the printing process do not affect the effect of the NiTiCu superelastic material intelligent coating, and their depth can be ignored.

[0041] Furthermore, in step four, the thickness of the NiTiCu superelastic material smart coating is between 2-8 mm. In principle, the thickness of the NiTiCu superelastic material smart coating should be less than one-sixth of the outer diameter of the fastener thread.

[0042] Furthermore, the printing parameters in step four are as follows: spot diameter 1-3mm, laser power 400-600W, scanning speed 200-400mm / min, powder feeding rate 10-30g / min, protective gas flow rate 8-12L / min, and powder carrier gas flow rate 8-13L / min.

[0043] Furthermore, in step five, the overall structure of the fastener with the NiTiCu superelastic material intelligent coating is horizontally clamped by a jig. The jig rotates around the central axis of the overall structure of the fastener with the NiTiCu superelastic material intelligent coating. After processing each fastener head side, the laser processing is stopped, the jig rotates so that the next fastener head side faces upward, and the processing of the next side continues until all sides are processed.

[0044] Furthermore, in step five, the non-smooth structure parameters are: the diameter of each pit structure is 1mm, the depth of each pit structure is 0.5-1mm, and the distance between two adjacent pit structures is 1mm.

[0045] The principle of this invention:

[0046] The biomimetic intelligent fastener prepared by this invention, in combination with a hyperelastic material and a snap-fit ​​structure, can adaptively and intelligently respond to abnormal loads in special environments such as the continuous high pressure of deep-sea exploration, frequent impacts in aerospace, and the continuous high temperature and pressure in nuclear weapons, maintaining a continuous fastening. In this invention, after the biomimetic intelligent fastener is assembled, the external load is within the normal assembly load range. When the external load suddenly increases, i.e., when subjected to abnormal loads such as impacts, continuous high temperatures, or high pressures, the snap-fit ​​structure is microscopically subjected to load compression, generating stress on both sides of the snap-fit ​​joint. This applies a load to the NiTiCu hyperelastic material intelligent coating. After being subjected to abnormal loads, the NiTiCu hyperelastic material intelligent coating rapidly rebounds and expands, increasing the overall stress of the biomimetic intelligent fastener while simultaneously lifting the external snap-fit ​​structure to resist relative sliding between the working surfaces, thus increasing the fit of the biomimetic intelligent fastener. When the abnormal external load recovers, each structure sequentially returns to its appropriate size to meet the intelligent fastening requirements in special environments.

Claims

1. A method for manufacturing biomimetic smart fasteners based on laser-directed energy deposition, characterized in that: Includes the following steps: Step 1: Construct the fastener and corresponding parameters of the snap-fit ​​structure, print the layered contour data and deposition path; Step 2: Based on the snap-fit ​​structure printing layer contour data and deposition path generated in Step 1, NiTiNb superelastic powder material is delivered in real time through laser powder bed melting technology, and the overall structure of the fastener is printed according to the set printing parameters, thereby obtaining the overall structure of the fastener. Step 3: Construct the printing layer profile data and deposition workflow for the NiTiCu superelastic material smart coating; Step 4: Based on the printing layer contour data and deposition path of the NiTiCu superelastic material smart coating generated in Step 3, a NiTiCu superelastic material smart coating of a specific thickness is printed on the working surface of the overall structure of the fastener and the side of the fastener head according to the set printing parameters using directional energy deposition technology. The thickness of the NiTiCu superelastic material smart coating is between 2-8mm. Step 5: The fastener with NiTiCu superelastic material smart coating processed in Step 4 is processed according to the set non-smooth structure parameters. A pit array is sintered on the NiTiCu superelastic material smart coating on each side of the fastener head using directional energy deposition technology. The snap-fit ​​structure with the corresponding parameters in step one is as follows: the length of the snap-fit ​​structure should be less than or equal to one-sixth of the outer diameter of the fastener thread; on the smooth section a of the fastener, along its axial direction, the interval between two adjacent snap-fit ​​structures is the length of one snap-fit ​​structure; the angle between two adjacent snap-fit ​​structures on the same circumferential surface of the smooth section a of the fastener is 90°; the working direction of the snap-fit ​​structure on the smooth section a of the fastener extends along the axial direction of the fastener towards the head of the fastener; on the threaded section b of the fastener, snap-fit ​​structures are arranged starting from the second level of thread; the angle between two snap-fit ​​structures arranged opposite each other on the same level of thread is 180°; the snap-fit ​​structures on adjacent levels of thread are arranged in a 90° staggered pattern; the working direction of the snap-fit ​​structure on the threaded section b is consistent with the thread direction. The snap-fit ​​structure is a snap-fit ​​structure with a U-shaped cavity.

2. The method for manufacturing biomimetic smart fasteners based on laser-directed energy deposition according to claim 1, characterized in that: In step two, the printing parameters are: laser spot diameter 1-3mm, laser power 400-600W, and scanning speed 200-400mm / min.

3. The method for manufacturing biomimetic smart fasteners based on laser-directed energy deposition according to claim 1, characterized in that: In step four, the detailed method for printing a NiTiCu superelastic material smart coating of a specific thickness on the working surface of the overall structure of the fastener and the side of the fastener head using directional energy deposition technology is as follows: The fastener's overall structure is held horizontally by a clamp, which rotates uniformly around the central axis of the fastener's overall structure. The rotation speed should be calculated based on the diameter of the fastener's overall structure and the scanning speed. It is also necessary to ensure that the NiTiCu superelastic material intelligent coating is printed uniformly along the axial direction of the fastener's overall structure. When printing reaches the snap-fit ​​structure, the laser needs to be paused to ensure that there is no NiTiCu superelastic material intelligent coating on the back of the snap-fit ​​structure.

4. The method for manufacturing biomimetic smart fasteners based on laser-directed energy deposition according to claim 3, characterized in that: In step four, the thickness of the NiTiCu superelastic material smart coating of a specific thickness should be less than one-sixth of the outer diameter of the fastener thread.

5. The method for manufacturing biomimetic smart fasteners based on laser-directed energy deposition according to claim 4, characterized in that: The printing parameters in step four are as follows: spot diameter 1-3mm, laser power 400-600W, scanning speed 200-400mm / min, powder feeding rate 10-30g / min, protective gas flow rate 8-12L / min, and powder carrier gas flow rate 8-13L / min.

6. The method for manufacturing biomimetic smart fasteners based on laser-directed energy deposition according to claim 1, characterized in that: In step five, the overall structure of the fastener with the NiTiCu superelastic material smart coating is horizontally clamped by a jig. The jig rotates around the central axis of the overall structure of the fastener with the NiTiCu superelastic material smart coating. After processing each fastener head side, the laser processing is stopped, the jig rotates so that the next fastener head side faces upward, and the processing of the next side continues until all sides are processed.

7. A method for manufacturing biomimetic smart fasteners based on laser-directed energy deposition according to claim 6, characterized in that: In step five, the non-smooth structure parameters are: the diameter of each pit structure is 1mm, the depth of each pit structure is 0.5-1mm, and the distance between two adjacent pit structures is 1mm.

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