A worm gear manufacturing process method applied to a humanoid robot dexterous hand

Abstract

This application relates to the field of micro-mechanical component manufacturing technology, and discloses a manufacturing process for a worm gear in a humanoid robot's dexterous hand, comprising: S1, preparing a sacrificial layer template with a three-dimensional negative mold and a micro-anchoring structure using photolithography; S2, conformally depositing a functional surface shell using atomic layer deposition (ALD) and forming corresponding prefabricated physical interlocks thereon; S3, depositing an intermediate bonding layer with a material composition gradient; S4, melting a metal material using additive manufacturing to form a structural body, wherein in S4, the high-temperature molten metal undergoes atomic diffusion to form metallurgical bonds when in contact with the intermediate bonding layer, and simultaneously fills into the prefabricated physical interlocks and solidifies to form a micro-mechanical interlock; and S5, removing the sacrificial layer template. This invention achieves a strong bond between the metal substrate and the ceramic shell through the synergistic effect of metallurgical bonding and micro-mechanical interlocks, producing a heterogeneous composite worm gear that is hard on the outside and tough on the inside, and is precisely formed.

Description

Technical Field

[0001] This invention relates to the field of micro-mechanical component manufacturing technology, specifically to a manufacturing process for a worm gear in the dexterous hand of a humanoid robot. Background Technology

[0002] Cutting-edge fields such as humanoid robots, precision medical devices, and aerospace place extremely stringent performance requirements on their core micro-transmission components, such as micro worm gears. An ideal micro worm gear needs to have a lightweight and highly resilient structural body to withstand complex mechanical loads and impacts, as well as a high-hardness, low-friction functional surface to resist the intense sliding friction and wear during tooth meshing.

[0003] It is difficult to meet these conflicting performance indicators simultaneously using a single homogeneous material. For example, although lightweight metal materials such as titanium alloys have excellent toughness and lightweight characteristics, their tribological properties are generally poor and their wear resistance is insufficient. They are prone to adhesive wear under high contact stress. On the other hand, although engineering ceramics have extremely high hardness and wear resistance, their inherent high brittleness makes them difficult to use as the main body of a structure to withstand impact and tensile loads, and they are prone to catastrophic brittle fracture.

[0004] Therefore, those skilled in the art have generally turned to the study of heterogeneous composite structures, that is, to prepare a layer of hard ceramic wear-resistant material on a lightweight metal substrate, in order to achieve complementary performance of hard exterior and tough interior. However, such metal-ceramic heterogeneous composite structures have long faced a fundamental technical bottleneck: the reliability of the bonding at the interface between the two materials. Metals and ceramics have huge differences in lattice structure, coefficient of thermal expansion and elastic modulus. This leads to the inevitable accumulation of very high residual stress at the interface during the coating preparation process and the service of the component. The interfacial bonding force formed by traditional coating processes is usually weak, mainly relying on physical adsorption or limited diffusion. This fragile interface is prone to failure under high stress concentration. Under the high shear stress and cyclic load required by worm gear drives, hard coatings are prone to cracking, blistering or even large-area peeling, causing the entire precision component to be scrapped prematurely, which seriously limits its application in high-performance fields. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a manufacturing process for worm gears in the dexterous hand of humanoid robots. This method solves the problem that in existing heterogeneous composite micro-transmission components, the interfacial bonding strength between the metal substrate and the ceramic functional layer is insufficient due to the mismatch of thermophysical properties, which easily leads to functional layer cracking and peeling failure when subjected to high shear stress and cyclic loads.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a manufacturing process for a worm gear in a dexterous hand of a humanoid robot, comprising the following steps:

[0007] S1: Provide a substrate and prepare a sacrificial layer template on the substrate; the sacrificial layer template has a three-dimensional negative mold for tooth surface forming, and a micro-anchoring structure is integrally formed on the side of the three-dimensional negative mold facing away from the substrate;

[0008] S2: A functional surface shell is conformally deposited on the surface of the sacrificial layer template, the functional surface shell filling and covering the micro-anchoring structure to form a prefabricated physical latch;

[0009] S3: Deposit an intermediate bonding layer with a material composition gradient on the side of the functional surface shell opposite to the substrate;

[0010] S4: Using the intermediate bonding layer with material composition gradient as the additive manufacturing interface, the metal material is melted using additive manufacturing process to fill and form the structural body; the metal material achieves metallurgical bonding with the intermediate bonding layer with material composition gradient during the melting process, and achieves micro-mechanical interlocking with the prefabricated physical interlock after solidification.

[0011] S5: Remove the sacrificial layer template and release the worm gear that is integrally formed with the structural body and the functional surface shell.

[0012] Preferably, in step S1, the sacrificial layer template is prepared on a polymer material using photolithography.

[0013] Preferably, the micro-anchoring structure is an array of inverted conical holes.

[0014] Preferably, in step S2, the functional surface shell is conformally deposited using atomic layer deposition.

[0015] Preferably, the material of the functional surface shell is amorphous tungsten carbide.

[0016] Preferably, the gradient intermediate bonding layer is deposited in S3 using a multi-target magnetron sputtering physical vapor deposition process.

[0017] Preferably, the intermediate bonding layer with a material composition gradient includes an adhesion layer and a compatibility layer; the adhesion layer is located on the functional surface shell, the compatibility layer is located on the adhesion layer, and the material composition gradient is achieved through a gradual change in material composition between the adhesion layer and the compatibility layer.

[0018] Preferably, the material of the adhesion layer is chromium, and the material of the compatibility layer is titanium.

[0019] Preferably, the additive manufacturing process in S4 is a micro selective laser melting process.

[0020] Preferably, the metal material in S4 is a titanium alloy.

[0021] This invention provides a manufacturing process for a worm gear in a dexterous hand of a humanoid robot, which has the following advantages:

[0022] 1. The present invention uses an intermediate bonding layer with a compositional gradient set in step S3 and a prefabricated physical interlock formed in steps S1 and S2. During additive manufacturing in step S4, the high-temperature molten metal simultaneously activates a dual interface locking mechanism of metallurgical bonding and micro-mechanical interlocking. This chemical and physical synergy fundamentally solves the technical problem of easy peeling between the metal matrix and the ceramic shell due to performance mismatch, endowing the composite interface with extremely high shear strength and peel strength, ensuring the reliability of the worm gear under high load.

[0023] 2. This invention combines the lightweight and high-toughness structural body formed by the selective laser melting process of S4 with the ultra-hard and wear-resistant functional surface shell formed by the atomic layer deposition process of S2. The resulting composite structure with an outer hardness and inner toughness achieves comprehensive performance advantages that cannot be achieved by a single homogeneous material, that is, it retains the impact resistance of metal and the wear resistance and low friction of ceramic.

[0024] 3. This invention utilizes photolithography in step S1 to prepare a sacrificial layer template. Its three-dimensional negative model accurately reproduces the complex contour of the worm gear tooth surface. The atomic layer deposition process in step S2 has extremely high conformality, ensuring that the functional surface shell can accurately replicate the complex tooth surface with uniform thickness. This process combination breaks through the limitations of traditional micromachining and realizes the integrated precision molding of complex three-dimensional mechanical parts at the micron scale. Attached Figure Description

[0025] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0026] The technical solutions in the embodiments 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, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] Please see the appendix Figure 1This invention provides a manufacturing process for a worm gear in a humanoid robot's dexterous hand. The worm gear manufactured by this method has the following structure: a structural body, a functional surface shell, and a composite interface layer located between the structural body and the functional surface shell.

[0028] The structural body constitutes the main body of the worm gear and is used to bear mechanical loads. Its material is preferably a high-toughness, lightweight metal material, and one embodiment is a titanium alloy.

[0029] The functional surface shell forms the meshing tooth surface of the worm gear, which is used to resist wear and reduce friction. Its material is preferably a high-hardness, wear-resistant material, and one embodiment is amorphous tungsten carbide.

[0030] The composite interface layer is a transitional structure that enables a firm bond between the structural body and the functional surface shell. In terms of microstructure, the composite interface layer is a combination of two bonding mechanisms.

[0031] 1. Metallurgical bonding: An intermediate bonding layer with a material composition gradient is provided between the functional surface shell and the structural body. One side of the intermediate bonding layer is attached to the functional surface shell, and the other side of the intermediate bonding layer forms a metallurgical diffusion zone between the intermediate bonding layer and the structural body. This metallurgical diffusion zone corresponds to the result of metallurgical bonding in step S4, thereby achieving chemical bonding.

[0032] 2. Micro-mechanical interlock: On the side of the functional surface shell opposite to its functional tooth surface, a prefabricated physical latch is integrally formed. The prefabricated physical latch has an inverted geometry. The material of the structural body is filled around the prefabricated physical latch. After solidification, a micro-mechanical interlock structure is formed. This micro-mechanical interlock structure corresponds to the result of the micro-mechanical interlock in step S4, thereby realizing physical locking.

[0033] Step S1 of the present invention begins by providing a substrate, preferably a monocrystalline silicon wafer, to be compatible with subsequent micro / nano fabrication processes, on which a sacrificial layer template is prepared.

[0034] In one specific embodiment, the sacrificial layer template is made of a polymer material, preferably a photosensitive resin suitable for two-photon polymerization or grayscale photolithography, such as modified SU-8 or polyimide and other high heat-resistant photoresists. It is uniformly coated on the substrate by spin coating or other methods. Subsequently, photolithography is used to expose and develop the polymer material to form the sacrificial layer template. The sacrificial layer template has a three-dimensional negative mold for tooth surface forming. The surface contour of the three-dimensional negative mold accurately reproduces the negative space of the worm gear tooth surface, and its surface finish is determined by the precision of the photolithography process.

[0035] As a technical feature of step S1 of the present invention, while preparing a three-dimensional negative mold using photolithography, a micro-anchoring structure is integrally formed on the side of the three-dimensional negative mold facing away from the substrate. In this embodiment, the photolithography technology is two-photon polymerization technology or grayscale photolithography technology. This technology precisely controls the exposure dose in three-dimensional space and integrally prepares a micro-anchoring structure with a specific topological morphology on the surface.

[0036] In one specific embodiment, the micro-anchoring structure is an inverted conical hole array. For example, in this embodiment, the opening diameter of the hole array is 1-5 μm, the depth is 5-15 μm, and the cone angle is 100-120°. The inverted conical hole array refers to multiple micropores formed on the surface, with the hole diameter gradually increasing from the surface to the interior, that is, towards the substrate. This inverted geometry is the basis for realizing subsequent micro-mechanical interlocking.

[0037] Step S2 is performed on the surface of the sacrificial layer template formed in S1 to conformally deposit the functional surface shell.

[0038] In one specific embodiment, an atomic layer deposition (ALD) process is used to deposit a functional surface shell. The ALD process is based on a self-limiting surface chemical reaction between precursor A and precursor B, and a complete ALD cycle N... cycle Including precursor A pulse, purge, precursor B pulse, and purge, the final functional layer thickness H func Given the number of loops N cycle The growth rate per cycle (GPC) determines:

[0039] H func =N cycle ×GPC

[0040] Where H func It is the thickness of the functional surface shell, N cycle It represents the total number of deposition cycles, and GPC represents the growth rate per cycle.

[0041] The self-confined nature of atomic layer deposition (ALD) gives it extremely high conformality, which ensures that the deposited material has a uniform thickness H. func All exposed surfaces of the covering sacrificial layer template, including the smooth surface of the three-dimensional negative mold and the complex inner walls of the micro-anchoring structure.

[0042] The functional surface shell is made of amorphous tungsten carbide to provide high hardness and wear resistance.

[0043] As a technical feature of step S2 of the present invention, in the conformal deposition process, the material of the functional surface shell is amorphous tungsten carbide in this embodiment, which fills and covers the micro-anchoring structure, which is an array of inverted conical holes in this embodiment. Since the micro-anchoring structure has an inverted geometry, after the functional surface shell is filled with the structure, a solid protrusion with an inverted feature is formed on the side of itself away from the substrate. This solid protrusion is the prefabricated physical latch in S2.

[0044] On the side of the functional surface shell formed in S2 that is away from the substrate, i.e. the side where the prefabricated physical latch is located, step S3 is performed to deposit an intermediate bonding layer with a material composition gradient.

[0045] An intermediate bonding layer is deposited in the same vacuum chamber using a multi-target magnetron sputtering physical vapor deposition process. The intermediate bonding layer serves as a functional surface shell, which in this embodiment is amorphous tungsten carbide ceramic, and the structural body formed in S4 in this embodiment is titanium alloy metal, with a physicochemical transition between the two.

[0046] The intermediate bonding layer with a material composition gradient includes an adhesion layer and a compatibility layer. The adhesion layer is located on the functional surface shell. In one embodiment, the material of the adhesion layer is chromium, which has excellent chemical adhesion to the functional surface shell, i.e., amorphous tungsten carbide.

[0047] The compatibility layer is located above the adhesion layer. In one embodiment, the compatibility layer is made of titanium. Titanium has high chemical compatibility with the additively manufactured metal material, namely titanium alloy, in S4, and is used to induce subsequent metallurgical bonding. The physical vapor deposition process ensures that the intermediate bonding layer completely covers the surface of the prefabricated physical latch.

[0048] The material composition gradient is achieved through the gradual change in material composition between the adhesion layer and the compatibility layer. Specifically, in the multi-target magnetron sputtering process, after depositing the adhesion layer, the chromium target power is not completely turned off, while the titanium target power is gradually turned on, forming a gradient zone with continuously changing chromium and titanium composition between the adhesion layer and the compatibility layer. This design avoids abrupt changes in material properties and effectively buffers the interfacial stress caused by the mismatch between the two host materials due to the thermal expansion coefficient and elastic modulus.

[0049] In step S4, the composite structure serves as the substrate for additive manufacturing. The intermediate bonding layer with a material composition gradient, specifically its outermost compatibility layer, acts as the additive manufacturing interface. The additive manufacturing process is used to melt the metal material to form the structural body.

[0050] In one specific embodiment, the additive manufacturing process is a micro-selective laser melting process, which includes: laying a layer of micron-sized metal powder, i.e., metal material. To ensure the subsequent melting quality, the particle size D50 of the metal powder is preferably 10μm to 25μm. The metal material is preferably a titanium alloy. One embodiment is an alloy containing 6% aluminum and 4% vanadium with a titanium matrix. It should be noted that for the laying of the first layer of powder on a substrate with a microstructure, it is necessary to optimize the speed and pressure of the scraper or roller, and possibly supplement it with electrostatic or vibration-assisted powder laying technology to ensure uniformity.

[0051] Subsequently, the high-energy laser beam selectively scans the metal powder according to the digital model slice data of the worm gear structure, and the laser volume energy density E d Its unit is J / mm 3 Determined by laser power P, scanning speed v, scanning spacing h, and layer thickness t:

[0052]

[0053] Where P is the laser power, v is the scanning speed, h is the scanning interval, and t is the powder layer thickness. In this embodiment, the layer thickness t is set to 20 μm.

[0054] To ensure the thermal stability of the S1 sacrificial layer template during the S4 laser melting process, an active cooling scheme can be adopted, such as fixing the substrate on a cooling stage at -10°C.

[0055] By controlling the energy density E d Within a precise process window—that is, an energy range that allows for metallurgical bonding without damaging the underlying sacrificial template—for example, when the laser power P is 50-100W, the scanning speed v is 500-1500mm / s, the scanning spacing h is 50μm, and the layer thickness t is 20μm, strong metallurgical bonding can be achieved, causing the metal powder to melt and form a micro-molten pool, which then bonds with the underlying intermediate bonding layer. After the molten pool solidifies, a solidified layer of the structural body is formed. The powder spreading and melting steps are repeated until the structural body is completely formed.

[0056] In step S4, when the high-temperature micro-melt pool, i.e., the molten metal material, comes into contact with the intermediate bonding layer, two interface locking mechanisms are activated simultaneously:

[0057] Mechanism 1: Achieving metallurgical bonding. The molten titanium alloy in the micro-melting pool comes into contact with the outermost titanium compatibility layer of the intermediate bonding layer. Since the two are homogeneous or highly compatible materials, the high temperature of the molten pool promotes the rapid interdiffusion of atoms at the interface, forming a nanoscale metallurgical diffusion zone between them. After solidification, this diffusion zone achieves a strong metallurgical bond between the structural body and the intermediate bonding layer.

[0058] Mechanism 2: The realization of micro-mechanical interlocking. At the same time, the highly fluid micro-melt pool flows through and completely fills the gaps around the prefabricated physical interlocking originating from S2, which is covered by the intermediate bonding layer. When the micro-melt pool cools and solidifies, the resulting solid structure body and the prefabricated physical interlocking, i.e., the solid protrusion with the inverted interlocking feature, interlock and lock with each other, forming a strong micro-mechanical interlocking structure. This structure provides strong shear resistance and peel resistance.

[0059] Step S4 solves the problem of strong bonding at the interface of heterogeneous materials through the synergistic effect of the aforementioned metallurgical bonding and micromechanical interlocking.

[0060] After completing additive manufacturing in step S4, proceed to step S5 to remove the sacrificial layer template.

[0061] The composite component, which has been additively manufactured, is separated from the substrate and placed in a specific removal environment, such as an oxygen plasma ashing process. This ashing process has a high selective removal rate for the sacrificial template after exposure and curing in S1, while being chemically inert to the materials of the functional surface shell and the structural body. The reactive gas contacts the internal sacrificial template through permeation and completely vaporizes and removes it.

[0062] After the sacrificial layer template is removed, the worm gear product, which is integrally formed by the structural body and the functional surface shell, is finally released.

[0063] Example 1

[0064] This embodiment provides a manufacturing process for a worm gear in a dexterous hand of a humanoid robot, and the detailed description of steps S1 to S5 is as follows:

[0065] S1: Provide a single-crystal silicon substrate. Using two-photon polymerization lithography, a modified SU-8 high heat-resistant photoresist sacrificial layer template is prepared on the substrate. The template is integrally formed with a three-dimensional negative mold of worm gear teeth. An inverted conical hole array is prepared on the side of the negative mold away from the substrate. The opening diameter is 1-5μm, the depth is 5-15μm, and the cone angle is 100-120° as a micro-anchoring structure. To ensure the thermal stability of S4, the substrate is fixed on a cooling stage at -10℃.

[0066] S2: Atomic layer deposition process is used with W(CO)6 and C2H 5· Plasma is used as a precursor, and conformally deposited amorphous tungsten carbide is used as a functional surface shell. The amorphous tungsten carbide material fills the inverted conical holes to form corresponding prefabricated physical latches.

[0067] S3: Using a multi-target magnetron sputtering process, a chromium adhesion layer and a titanium compatibility layer are deposited sequentially, and an intermediate bonding layer with a Cr-Ti composition gradient is formed between the two layers;

[0068] S4: A micro-selective laser melting process is employed, using a Ti-6Al-4V titanium alloy powder layer with a thickness of t = 20 μm as the metal material to form the structural body. The laser parameter window is controlled as follows: power P = 50-100W, velocity v = 500-1500 mm / s, spacing h = 50 μm, and energy density E... d Approximately 33-133 J / mm 3 The high-temperature molten pool forms a metallurgical bond with the titanium compatibility layer of S3, while filling and covering the prefabricated physical interlocks of S2 to form a micro-mechanical interlock. Vibration-assisted technology is used when laying the first layer of powder.

[0069] S5: Using oxygen plasma ashing process, the SU-8 sacrificial layer template is selectively removed, releasing the TC4 / WC heterogeneous composite worm gear finished product.

[0070] Example 2

[0071] The main difference between this embodiment and Embodiment 1 is that the materials used are different.

[0072] The functional surface shell in S2 is made of titanium nitride material deposited using the ALD process. Titanium nitride also has high hardness and wear resistance.

[0073] The intermediate bonding layer in S3: the adhesion layer is still chromium, which has good adhesion to titanium nitride. The compatibility layer corresponds to the material in S4, and is changed to the main components in 316L stainless steel, such as the nickel layer.

[0074] The structural body in S4 is made using SLM technology, and the metal material is 316L stainless steel powder.

[0075] Example 3

[0076] The main difference between this embodiment and Embodiment 1 lies in the specific morphology and preparation method of the micro-anchoring structure in S1.

[0077] The sacrificial layer template in S1: The micro-anchoring structure prepared on the sacrificial layer template using grayscale photolithography is a T-shaped protrusion array or a mushroom-shaped array;

[0078] The functional surface shell in S2: Amorphous tungsten carbide material deposited by ALD conformally covers the T-shaped boss array, and a corresponding inverted groove is naturally formed on the side away from the substrate, i.e., the top of the T-shape. This groove is the prefabricated physical latch in this embodiment.

[0079] Molten TC4 titanium alloy in S4 flows into and fills the inverted groove formed in S2, and solidifies to form a strong micro-mechanical interlock.

[0080] Comparative Example 1

[0081] The process steps in this comparative example are almost identical to those in Example 1, with the only key difference being:

[0082] In step S1, only the three-dimensional negative model was prepared, but the inverted conical hole array, i.e. the micro-anchoring structure, was not prepared.

[0083] In step S4, the bonding between the TC4 titanium alloy and the amorphous tungsten carbide layer relies solely on metallurgical bonding.

[0084] Comparative Example 2

[0085] The key difference between the process steps in this comparative example and those in Example 1 is:

[0086] The S3 step of depositing an intermediate bonding layer with a material composition gradient was omitted;

[0087] In step S4, the TC4 titanium alloy powder melted by SLM comes into direct contact with the amorphous tungsten carbide functional surface shell formed in step S2. Due to the huge difference in thermophysical properties and extremely poor chemical compatibility between TC4 and amorphous tungsten carbide, they cannot form effective metallurgical bonds, and the interfacial bonding mainly relies on micro-mechanical interlocking.

[0088] Comparative Example 3

[0089] This comparative example uses the traditional process mentioned in the background section:

[0090] First, a complete TC4 titanium alloy worm gear is prepared using traditional precision machining or SLM additive manufacturing.

[0091] Then, the finished worm gear is placed in the PVD cavity, and an amorphous tungsten carbide wear-resistant coating is deposited on its tooth surface;

[0092] In this process, the amorphous tungsten carbide coating and the TC4 substrate have only the traditional PVD thin film adhesion, without micro-mechanical interlocking or high-temperature metallurgical bonding.

[0093] Performance Tests and Results

[0094] Interface shear strength test:

[0095] The test was conducted on a micron-level mechanical testing system equipped with a high-precision force sensor, and referenced the shear test concepts in JIS H8504 and ASTM F1044. During the test, a flat-headed punch was used to apply a shear force parallel to the composite interface at a constant displacement rate of 10 μm / s until the functional surface shell peeled off. The maximum load F at the point of peeling was recorded by the force sensor. max And according to the formula τ=F max / A, where A is the contact area of ​​the shear region, is used to calculate the final interfacial shear strength.

[0096] Cyclic load wear resistance test:

[0097] The test was conducted on a dedicated micro-transmission test bench. After the worm gear samples of the examples and comparative examples were installed, they were meshed with a standard grinding worm, such as 40Cr steel. The test was carried out at a cyclic frequency of 20Hz under 150% overload of rated torque, with a total number of cycles set to 1 million. Throughout the test, the peeling of the tooth surface coating and the wear morphology were monitored in real time using a high-magnification microscope and online acoustic emission signals.

[0098] Friction coefficient test:

[0099] Referring to ASTM G99-17 or GB / T12444.2-2007 standards, the tests were conducted on a miniature tribological testing machine using a ball-disc model. To comply with ASTM G99 standards, we used the exact same process as in the examples and comparative examples, preparing planar sample disks with the same composite interface on a flat substrate. High-hardness silicon nitride ceramic balls were selected as the grinding pair. Under dry friction conditions at room temperature (25℃±2℃), a normal load of 1N was applied, and the test was conducted continuously for 30 minutes at a sliding speed of 0.1m / s. The system recorded the frictional force in real time using a high-sensitivity force sensor and calculated the frictional force according to the formula μ=F. friction / F normal The dynamic friction coefficient is automatically calculated and ultimately taken as the average value during the stable testing phase.

[0100] Test Results Summary Table:

[0101]

[0102] Results analysis:

[0103] 1. The results of the interfacial shear strength test directly prove the interfacial bonding ability of the present invention. The interfacial shear strength of Examples 1, 2, and 3 all exceed 170 MPa, which is a very high value. In contrast, Comparative Example 1 lacks the micro-interlocking structure, and its strength immediately drops to 72 MPa. Comparative Example 2 lacks the intermediate bonding layer, and its strength is only 45 MPa. These data clearly show that only by combining the two mechanisms of metallurgical bonding and micro-mechanical interlocking can a sufficiently high interfacial bonding strength be obtained. The effect produced by this combination is far greater than the effect of any single mechanism, thereby fundamentally ensuring that the ceramic shell will not be sheared or peeled off from the metal matrix.

[0104] 2. The results of the cyclic load wear resistance test proved the long-term service capability of the present invention under high load. The worm gears prepared in Examples 1, 2 and 3, after undergoing 1 million cycles under 150% overload conditions, had intact tooth surface functional layers. In contrast, Comparative Example 3, which uses existing PVD technology, experienced severe peeling of the coating in less than 50,000 cycles under the same conditions. This huge performance difference is due to the excellent interfacial bonding force of the present invention. It is precisely because the ceramic shell is firmly locked on the metal substrate that the ceramic layer can continue to play its wear resistance role without failure.

[0105] 3. The test results of the dynamic friction coefficient verified the advantages of the present invention in terms of transmission efficiency. The tooth surface friction coefficients of Examples 1, 2, and 3 were stably maintained at an extremely low level of 0.15 to 0.18. However, for the sample of Comparative Example 3, after the coating peeled off, the metal substrate came into direct contact, causing the friction coefficient to rise rapidly to above 0.7. This would cause huge energy loss and transmission failure in practical applications. This comparison proves that the present invention not only provides a low-friction ceramic surface, but more importantly, the present invention ensures that this low-friction surface can remain intact and stable during long-term operation through a dual locking mechanism.

[0106] In summary, the dual locking mechanism proposed in this invention, which combines S1 and S2 micro-locking and S3 and S4 metallurgical bonding, is the key to solving the problem of interface bonding of heterogeneous materials. Its beneficial effects far exceed those of existing technologies and solutions lacking key features.

[0107] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A worm manufacturing process method applied to a humanoid robot dexterous hand, characterized by, The method comprises the following steps: S1: providing a substrate and preparing a sacrificial layer template on the substrate; the sacrificial layer template has a three-dimensional negative mold for tooth surface forming, and micro anchoring structures are integrally formed on the side of the three-dimensional negative mold away from the substrate; S2: conformally depositing a functional surface shell on the surface of the sacrificial layer template, the functional surface shell filling and covering the micro anchoring structures to form a prefabricated physical lock; S3: depositing an intermediate bonding layer with a material composition gradient on the side of the functional surface shell away from the substrate; S4: taking the intermediate bonding layer with a material composition gradient as an additive manufacturing interface, and melting metal material to fill and form a structural body by using an additive manufacturing process; the metal material realizes metallurgical bonding with the intermediate bonding layer with a material composition gradient during melting, and realizes micro mechanical interlocking with the prefabricated physical lock after solidification; S5: removing the sacrificial layer template to release the worm gear integrally formed by the structural body and the functional surface shell.

2. The worm manufacturing process method for anthropomorphic robot hand according to claim 1, wherein, The sacrificial layer template in S1 is prepared on a polymer material by using a photolithography technology.

3. The method for manufacturing worm gear for anthropomorphic robot hand according to claim 1, wherein, The micro anchoring structures are inverted conical hole arrays.

4. The method for manufacturing worm gear for anthropomorphic robot hand according to claim 1, wherein, The functional surface shell in S2 is conformally deposited by using an atomic layer deposition process.

5. The method for manufacturing worm gear of anthropomorphic robot dexterous hand according to claim 4, characterized in that, The material of the functional surface shell is amorphous tungsten carbide.

6. The worm manufacturing process method for anthropomorphic robot hand according to claim 1, wherein, The gradient intermediate bonding layer in S3 is deposited by using a multi-target magnetron sputtering physical vapor deposition process.

7. The worm manufacturing process method for anthropomorphic robot hand according to claim 6, wherein, The intermediate bonding layer with a material composition gradient comprises an adhesion layer and a compatible layer; the adhesion layer is located above the functional surface shell, the compatible layer is located above the adhesion layer, and the material composition gradient is realized by the gradual change of material composition between the adhesion layer and the compatible layer.

8. The method for worm manufacturing process of dexterous hand for humanoid robot according to claim 7, characterized in that, The material of the adhesion layer is chromium, and the material of the compatible layer is titanium.

9. The worm manufacturing process method for anthropomorphic robot hand according to claim 1, wherein, The additive manufacturing process in S4 is a micro selective laser melting process.

10. The method for worm manufacturing process of dexterous hand for humanoid robot according to claim 1, wherein, The metal material in S4 is a titanium alloy.

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