Method for manufacturing bionic intelligent fastener based on laser directional energy deposition

Abstract

The invention discloses a method for manufacturing a bionic intelligent fastener based on laser directional energy deposition, and relates to the technical field of additive manufacturing, and the method comprises the following steps: step 1, constructing a fastener and a buckle structure with corresponding parameters, and printing layered contour data and a deposition working route; step 2, printing layered contour data and a deposition working route according to the buckle structure generated in the step 1, and printing an integral structure of the fastener according to set printing parameters; 3, printing layering contour data and a deposition working route of the NiTiCu super-elastic material intelligent coating are constructed; fourthly, a NiTiCu super-elastic material intelligent coating with the specific thickness is printed on the working surface of the overall structure of the fastener and the side face of the head of the fastener according to the set printing parameters through the directional energy deposition technology; and fifthly, the whole fastener structure with the NiTiCu super-elastic material intelligent coating machined in the fourth step is subjected to pit array machining according to set non-smooth structure parameters.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a method for manufacturing bionic intelligent fasteners based on laser directional energy deposition. Background Art

[0002] The world's industry is developing rapidly, and the scale of construction is increasing day by day. Fasteners have always played an important role in the construction of various buildings and industrialized equipment. Fasteners are mechanical parts that connect two or more mechanical parts to make them one. Fasteners are a type of mechanical parts with a very wide range of applications and a very large number of uses. Various fasteners can be seen on various mechanical equipment, transportation vehicles, infrastructure facilities, tools and instruments, etc. Because of the huge range of applications of fasteners and the important role they play, the processing requirements and manufacturing quality control of fasteners are very strict.

[0003] However, with the continuous development of upper-level technology and the growing demand for scientific exploration, the application of mechanical structures has become more complex and the service environment has become more severe. As an important part of the foundation, fasteners are also becoming more and more complex in the environment in which they serve. Under the influence of high-intensity loads in special environments such as deep sea, space, and high radiation, the service life of traditional fasteners has been significantly reduced, and the fastening strength is difficult to meet the requirements. After millions of years of evolution, nature has evolved adaptive, self-adjusting friction-enhancing structures. Among them, the barbed structure that adjusts the resistance through its own elasticity provides a feasible solution for the intelligent adjustment of fasteners, which can greatly improve the fastening performance of fasteners. At the same time, with the research on bionic coatings, fasteners with bionic coatings and structures are expected to adapt to loads in different special environments and achieve intelligent fastening. Summary of the invention

[0004] In view of the problem that the fastening strength of the above-mentioned existing fasteners decreases in special environments such as aerospace, deep-sea exploration, and high radiation, the present invention proposes a method for manufacturing bionic intelligent fasteners based on laser directed energy deposition.

[0005] A method for manufacturing a bionic intelligent fastener based on laser directed energy deposition comprises the following steps: Step 1: Construct the fastener and the corresponding parameters of the buckle structure to print the layered contour data and deposition work route; Step 2: Print the layered contour data and deposition work route of the buckle structure generated in step 1, deliver the NiTiNb superelastic powder material in real time through the laser powder bed melting technology, print the overall structure of the fastener according to the set printing parameters, and then obtain the overall structure of the fastener; Step 3: Construct the printing layered profile data and deposition work route of the NiTiCu superelastic material intelligent coating; Step 4: According to the printing layered profile data and deposition working route of the NiTiCu superelastic material intelligent coating generated in step 3, a layer of NiTiCu superelastic material intelligent 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 by using the directed energy deposition technology according to the set printing parameters; 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 structural parameters, and a pit array is sintered on each side of the fastener head on the NiTiCu superelastic material smart coating by directed energy deposition technology.

[0006] Preferably, the buckle structure of the corresponding parameters in the step 1 is as follows: the length of the buckle structure should be less than or equal to one sixth of the outer diameter of the fastener thread; in the axial direction of the smooth part of the a section of the fastener, the interval between two adjacent buckle structures is the length of one buckle structure, the angle between the two adjacent buckle structures on the same circumferential surface of the smooth part of the a section of the fastener is 90°, and the working direction of the buckle structure on the smooth part of the a section of the fastener extends along the axial direction of the fastener toward the head direction of the fastener; the buckle structure is arranged on the b section threaded part of the fastener starting from the second-level thread, the angle between the two buckle structures arranged relatively on the same-level thread is 180°, the buckle structures on the adjacent two-level threads are arranged in a staggered manner at 90°, and the working direction of the buckle structure on the b section threaded part is consistent with the thread direction; The buckle structure is a buckle structure with a U-shaped cavity.

[0007] Preferably, in step 2, the printing parameters are: laser spot diameter 1-3 mm, laser power 400-600 W, scanning speed 200-400 mm / min.

[0008] Preferably, in the step 4, the detailed method of printing a layer of NiTiCu superelastic material intelligent coating of a specific thickness on the working surface of the overall structure of the fastener and the side of the fastener head by using the directed energy deposition technology is as follows; The overall structure of the fastener is horizontally clamped by a fixture, and the fixture rotates at a constant speed around the central axis of the overall structure of the fastener. The rotation speed should be calculated based on the diameter size of the overall structure of the fastener and the scanning speed, and ensure that the NiTiCu superelastic material smart coating is evenly printed along the axial direction of the overall structure of the fastener. When printing to the buckle structure, the laser needs to be paused to ensure that there is no NiTiCu superelastic material smart coating on the back of the buckle structure.

[0009] Preferably, in step 4, the thickness of the NiTiCu superelastic material intelligent coating with a specific thickness should be less than one sixth of the outer diameter of the fastener thread.

[0010] Preferably, the printing parameters in step 4 are: spot diameter 1-3 mm, laser power 400-600 W, scanning speed 200-400 mm / min, powder feeding rate 10-30 g / min, protective gas flow rate 8-12 L / min, and powder carrier gas flow rate 8-13 L / min.

[0011] Preferably, in the step five, the overall structure of the fastener with the NiTiCu superelastic material smart coating is horizontally clamped by a fixture, and the fixture rotates around the central axis of the overall structure of the fastener with the NiTiCu superelastic material smart coating. After processing each side of the fastener head, the laser processing is stopped, the fixture is rotated, so that the next side of the fastener head faces upward, and the next side is processed; until all processing is completed.

[0012] Preferably, in step five, the non-smooth structure parameters are: the diameter of each pit structure is 1 mm, the depth of each pit structure is 0.5-1 mm, and the spacing between two adjacent pit structures is 1 mm.

[0013] Beneficial effects of the present invention: The bionic intelligent fasteners printed using the printing parameters and printing materials in this application have excellent elasticity and can overcome the problem of service fatigue to a certain extent; The NiTiCu superelastic material intelligent coating has sensitive elastic properties. When the external load is within the normal range, the strain of the NiTiCu superelastic material intelligent coating is small, and the overall structural fit of the bionic intelligent fastener is moderate. When a large load is applied from the outside, strain can be generated quickly, the stress of the NiTiCu superelastic material intelligent coating increases in a short time, and the fit of the bionic intelligent fastener increases rapidly to meet the fastening requirements under special environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work: Figure 1 A side view of the bionic intelligent fastener prepared by the present invention; Figure 2 yes Figure 1 Cross-sectional view at AA in the middle; Figure 3 yes Figure 1 Cross-section at the middle BB; Figure 4 It is a side view of the fixture holding the bionic smart fastener; Figure 5It is the bionic principle diagram of the snap-on structure. DETAILED DESCRIPTION

[0015] In order to make the purpose, processing design scheme and advantages of the embodiments of the present application clearer, the design scheme and manufacturing method in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiment drawings in the present application.

[0016] like Figures 1 to 5 As shown, a method for manufacturing a bionic intelligent fastener based on laser directed energy deposition comprises the following steps: Step 1: Construct the fastener and the corresponding parameters of the buckle structure to print the layered contour data and deposition work route; Step 2: Print the layered contour data and deposition work route of the buckle structure generated in step 1, deliver the NiTiNb superelastic powder material in real time through the laser powder bed melting technology, print the overall structure of the fastener according to the set printing parameters, and then obtain the overall structure of the fastener; Step 3: Construct the printing layered profile data and deposition work route of the NiTiCu superelastic material intelligent coating; Step 4: According to the printing layered profile data and deposition working route of the NiTiCu superelastic material intelligent coating generated in step 3, a layer of NiTiCu superelastic material intelligent 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 by using the directed energy deposition technology according to the set printing parameters; Step 5: The overall structure of the fastener with the NiTiCu superelastic material intelligent coating processed in step 4 is processed according to the set non-smooth structural parameters, and a pit array is sintered on each side of the fastener head on the NiTiCu superelastic material intelligent coating by directed energy deposition technology, thereby reducing the self-loosening of the bionic intelligent fastener due to working friction.

[0017] Furthermore, the buckle structure of the corresponding parameters in step 1 is: the length of the buckle structure is limited to between 3-9 mm, and the specific length needs to be adjusted according to the thickness of the NiTiCu superelastic material intelligent coating and the design size of the fastener. In principle, the length of the buckle structure should be less than or equal to one sixth of the outer diameter of the fastener thread; Figure 1As shown, in the smooth part of the a section of the fastener along its axial direction, the interval between two adjacent buckle structures is the length of one buckle structure, the angle between the two adjacent buckle structures on the same circumferential surface of the smooth part of the a section of the fastener is 90°, and the working direction of the buckle structure on the smooth part of the a section of the fastener extends along the axial direction of the fastener toward the head direction of the fastener; the buckle structure is arranged in the b section threaded part of the fastener starting from the second-level thread, the angle between the two buckle structures arranged relatively on the same-level thread is 180°, the buckle structures on the adjacent two-level threads are arranged in a staggered manner at 90°, and the working direction of the buckle structure on the b section threaded part is consistent with the thread direction; that is, the inclination direction of the buckle structure is always opposite to the working direction of the fastener; The buckle structure is designed based on the filiform papilla structure of the tongue of cats. The buckle structure is a buckle structure with a U-shaped cavity, and the root of the buckle structure is covered by a NiTiCu superelastic material intelligent coating.

[0018] Furthermore, in step 2, the printing parameters are: laser spot diameter 1-3 mm, laser power 400-600 W, scanning speed 200-400 mm / min.

[0019] Furthermore, in the step 4, the detailed method of printing a layer of NiTiCu superelastic material intelligent coating of a specific thickness on the working surface of the overall structure of the fastener and the side of the fastener head by using the directed energy deposition technology is as follows; The overall structure of the fastener is horizontally clamped by a fixture, and the fixture rotates at a constant speed around the central axis of the overall structure of the fastener. The rotation speed should be calculated based on the diameter size of the overall structure of the fastener and the scanning speed, and ensure that the NiTiCu superelastic material smart coating is evenly printed along the axial direction of the overall structure of the fastener. When printing to the buckle structure, the laser needs to be paused to ensure that there is no NiTiCu superelastic material smart coating on the back of the buckle structure. It should be noted that the grooves inevitably formed by the printing process have no effect on the effect of the NiTiCu superelastic material smart coating, and the depth can be ignored.

[0020] Furthermore, in step 4, the thickness of the NiTiCu superelastic material smart coating with a specific thickness 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.

[0021] Furthermore, the printing parameters in step 4 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.

[0022] Furthermore, in the step five, the overall structure of the fastener with the NiTiCu superelastic material smart coating is horizontally clamped by a fixture, and the fixture rotates around the central axis of the overall structure of the fastener with the NiTiCu superelastic material smart coating. After processing each side of the fastener head, the laser processing is stopped, the fixture is rotated, so that the next side of the fastener head faces upward, and the next side is processed; until all processing is completed.

[0023] Furthermore, in step five, the non-smooth structure parameters are: the diameter of each pit structure is 1 mm, the depth of each pit structure is 0.5-1 mm, and the distance between two adjacent pit structures is 1 mm.

[0024] Principle of the present invention: The bionic intelligent fastener prepared by the present invention can make the bionic intelligent fastener adaptively intelligently respond and continuously maintain fastening under abnormal loads in special environments such as continuous high pressure in deep-sea exploration, frequent collisions in aerospace, and continuous high temperature and high pressure in nuclear weapons under the cooperation of superelastic materials and buckle structures. In the present invention, after the bionic intelligent fastener is assembled, the external load is an assembly load within the normal range. When the external load suddenly increases, that is, when subjected to abnormal loads such as collision, continuous high temperature or high pressure, the buckle structure is first squeezed by the load at the microscopic level, generating stress on both sides of the bayonet, thereby applying a load to the NiTiCu superelastic material intelligent coating. After being subjected to the abnormal load, the NiTiCu superelastic material intelligent coating rebounds and expands rapidly, increasing the overall stress of the bionic intelligent fastener while lifting the external buckle structure to resist the relative sliding between the working surfaces, so that the bionic intelligent fastener has a greater degree of fit. When the external abnormal load is restored, each structure successively restores a moderate size to achieve the intelligent fastening requirements under special environments.

Claims

1. A method for manufacturing bionic intelligent fasteners based on laser directed energy deposition, characterized in that: The steps include: Step 1: Construct the fastener and the corresponding parameters of the buckle structure to print the layered contour data and deposition work route; Step 2: Print the layered contour data and deposition work route of the buckle structure generated in step 1, deliver the NiTiNb superelastic powder material in real time through the laser powder bed melting technology, print the overall structure of the fastener according to the set printing parameters, and then obtain the overall structure of the fastener; Step 3: Construct the printing layered profile data and deposition work route of the NiTiCu superelastic material intelligent coating; Step 4: According to the printing layered profile data and deposition working route of the NiTiCu superelastic material intelligent coating generated in step 3, a layer of NiTiCu superelastic material intelligent 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 by using the directed energy deposition technology according to the set printing parameters; 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 structural parameters, and a pit array is sintered on each side of the fastener head on the NiTiCu superelastic material smart coating by directed energy deposition technology.

2. The method for manufacturing bionic intelligent fasteners based on laser directed energy deposition according to claim 1, characterized in that: The buckle structure of the corresponding parameters in the step 1 is as follows: the length of the buckle structure should be less than or equal to one sixth of the outer diameter of the fastener thread; in the axial direction of the smooth part of the a section of the fastener, the interval between two adjacent buckle structures is the length of one buckle structure, the angle between the two adjacent buckle structures on the same circumferential surface of the smooth part of the a section of the fastener is 90°, and the working direction of the buckle structure on the smooth part of the a section of the fastener extends along the axial direction of the fastener toward the head direction of the fastener; the buckle structure is arranged on the b section threaded part of the fastener starting from the second-level thread, the angle between the two buckle structures arranged relatively on the same-level thread is 180°, the buckle structures on the adjacent two-level threads are arranged in a staggered manner at 90°, and the working direction of the buckle structure on the b section threaded part is consistent with the thread direction; The buckle structure is a buckle structure with a U-shaped cavity.

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

4. The method for manufacturing bionic intelligent fasteners based on laser directed energy deposition according to claim 1, characterized in that: In the step 4, the detailed method of printing a layer of NiTiCu superelastic material intelligent coating of a specific thickness on the working surface of the overall structure of the fastener and the side of the fastener head by using the directed energy deposition technology is as follows; The overall structure of the fastener is horizontally clamped by a fixture, and the fixture rotates at a constant speed around the central axis of the overall structure of the fastener. The rotation speed should be calculated based on the diameter size of the overall structure of the fastener and the scanning speed, and ensure that the NiTiCu superelastic material smart coating is evenly printed along the axial direction of the overall structure of the fastener. When printing to the buckle structure, the laser needs to be paused to ensure that there is no NiTiCu superelastic material smart coating on the back of the buckle structure.

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

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

7. The method for manufacturing bionic intelligent fasteners based on laser directed energy deposition according to claim 1, characterized in that: In the step 5, the overall structure of the fastener with the NiTiCu superelastic material smart coating is horizontally clamped by a fixture, and the fixture rotates around the central axis of the overall structure of the fastener with the NiTiCu superelastic material smart coating. After processing each side of the fastener head, the laser processing is stopped, the fixture is rotated, so that the next side of the fastener head faces upward, and the next side is processed; until all processing is completed.

8. The method for manufacturing bionic intelligent fasteners based on laser directed energy deposition according to claim 7, characterized in that: In the step 5, the non-smooth structure parameters are: the diameter of each pit structure is 1 mm, the depth of each pit structure is 0.5-1 mm, and the distance between two adjacent pit structures is 1 mm.

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