Copper conductor for robot equipment and preparation process thereof

Abstract

The invention belongs to the technical field of cables, and particularly relates to a copper conductor for robot equipment and a preparation process thereof. The preparation process of the copper conductor for the robot equipment comprises the following steps: carrying out primary twisting on a conductor material to form a single-strand wire; and re-stranding the single-strand wire to obtain the cable. Through reasonable structure design and material selection, the prepared copper conductor is excellent in mechanical property and high in yield strength; the bending and torsion resistance is excellent, and the service life is long; the flexible cable is very suitable for being applied to robot equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of cables, and in particular relates to a copper conductor for robot equipment and a preparation process thereof. Background Art

[0002] With the rapid development of modern industry and technology, robotic equipment plays a vital role in industrial automation, intelligent manufacturing, aerospace and other fields. Among them, high-performance copper conductor materials are the core components of robot flexible cables, and their performance is directly related to the stability and reliability of the entire robot system. In recent years, the performance verification and technical requirements of high-performance copper conductor materials have become a hot topic in the industry, aiming to provide better conductor solutions for robotic equipment through actual performance testing and verification.

[0003] Although there are many copper conductor materials used in robot flexible cables on the market, they still have many shortcomings in meeting high-performance requirements, especially poor mechanical stability. When the robot moves frequently or is subjected to large tensile forces, traditional copper conductors are prone to breakage or deformation, causing cable failure and affecting cable life.

[0004] In view of the above technical problems, the present invention proposes a copper conductor material and a preparation process thereof that can meet the requirements of high-performance robot equipment, so as to overcome the deficiencies in the prior art and improve the overall mechanical properties and service life of the robot flexible cable. Summary of the invention

[0005] The purpose of the present invention is to provide a copper conductor for robot equipment and a preparation process thereof, and the mechanical properties and service life of the prepared copper conductor are improved by rationally designing the structure and selecting the materials.

[0006] A preparation process of a copper conductor for robot equipment comprises the following steps: initially twisting the conductor material to form a single strand wire; and re-twisting the single strand wire to obtain a copper conductor.

[0007] Preferably, the conductor material is a tinned copper conductor.

[0008] Preferably, the method for preparing the tinned copper conductor comprises the following steps: annealing, pickling, tinning the copper wire in sequence, and then cleaning and drying.

[0009] Preferably, the copper wire has a copper purity of ≥99.95% and an oxygen content of <0.002%, and is purchased from Qingdao Hancable Co., Ltd.

[0010] Preferably, the specific conditions of the annealing are: 130-150°C in the first stage, keep warm for 5-10s; heat up to 280-300°C, keep warm for 5-10s; heat up to 450-480°C, keep warm for 1-5s, and cool to room temperature with the furnace.

[0011] The inventors found that by treating the copper wire with step-by-step annealing, the mechanical properties of the copper conductor can be improved while improving its flexibility and ductility. This may be because the surface and internal temperature of the copper wire are uniformed by preheating at a lower temperature, reducing the thermal stress caused by the temperature difference and avoiding deformation or cracking of the copper wire in subsequent high-temperature treatment; the temperature is further raised to 280-300°C, and the internal stress of the copper wire begins to be initially released, and the grains begin to be refined, which improves the flexibility and ductility of the copper wire; at a high temperature of 450-480°C, the internal stress of the copper wire is further eliminated, the grains are further refined, and recrystallization is promoted, which significantly improves the flexibility and ductility of the copper wire. Through step-by-step annealing, the internal stress of the copper wire is effectively released, the thermal stress caused by sudden temperature changes is reduced, the stability and uniformity of the copper wire in high-temperature treatment are ensured, and its fatigue resistance is improved, so that it is not easy to crack in repeated bending and twisting. The recrystallization process refines the grains of the copper wire, improves its tensile strength and mechanical properties, and enables it to withstand greater mechanical loads in robot equipment. In addition, the recrystallization process at high temperature can eliminate the defects and dislocations inside the copper wire, improve the crystallinity of the copper wire, and thus improve its conductivity. High temperature treatment can cause impurities on the surface and inside of the copper wire to volatilize or diffuse, further improving the purity of the copper wire and enhancing its conductivity.

[0012] The specific steps of pickling are: immersing the annealed copper wire in a pickling solution at room temperature for 1 to 3 minutes, then taking it out, washing the pickling solution remaining on the surface with deionized water and drying it.

[0013] Preferably, the solvent of the pickling solution is water, and the concentrations of the components in the pickling solution are: zinc chloride 10-20 g / L, ammonium chloride 10-20 g / L, sodium chloride 5-10 g / L, hydrochloric acid volume concentration 10-20%, ethanolamine 1-3 g / L, and emulsifier 0.1-0.5 g / L.

[0014] The inventors found that immersing the annealed copper wire in a specific pickling solution can not only remove the oxides and dirt on the surface of the copper wire, but also further improve the mechanical properties of the copper wire. This may be because the hydrochloric acid in the pickling solution can effectively remove the oxides and dirt on the surface of the copper wire; zinc chloride, ammonium chloride and sodium chloride can synergistically enhance the acidity of the pickling solution, promote the dissolution of oxides, and ensure thorough cleaning of the copper wire surface. The clean copper wire surface helps to uniformly cover the tin layer in the subsequent tinning process and improve the bonding strength of the coating. This ensures that the coating will not fall off during long-term use, improving the reliability and durability of the copper conductor; ethanolamine acts as a corrosion inhibitor and chelating agent to reduce excessive corrosion of the copper wire and improve the stability of the pickling solution. The synergistic effect of the various components in the pickling solution can not only reduce the tiny defects and unevenness on the surface of the copper wire, improve the surface quality of the copper wire, help improve the mechanical properties of the copper conductor, and reduce the risk of breakage caused by surface defects during use, but also the clean copper wire surface can form a more uniform and dense coating in the subsequent tinning process, improve the corrosion resistance, fatigue resistance and mechanical properties of the copper conductor, such as tensile strength and flexibility, which enables the copper conductor to withstand greater mechanical loads and repeated bending and twisting in robotic equipment, extending the service life of the copper conductor. In addition, the clean copper wire surface and uniform coating can reduce contact resistance and improve the conductivity of the copper conductor, which is crucial for signal transmission and power transmission in robotic equipment, ensuring the stability and reliability of the system.

[0015] Preferably, the emulsifier is Tween 60.

[0016] Preferably, the acid value of the Tween 60 is ≤2.0 mgKOH / g, and the hydroxyl value is 81-96 mgKOH / g.

[0017] In some preferred embodiments, the Tween 60 is purchased from Yingxin Laboratory.

[0018] Preferably, the specific step of tinning is: passing the copper wire into a tin furnace for tinning.

[0019] Preferably, the temperature of the molten tin in the tin furnace is 220-500°C.

[0020] Preferably, the aperture of the tin-plating mold in the tin furnace is 0.001-0.01 mm larger than the diameter of the copper wire after annealing.

[0021] Preferably, the tin liquid is molten tin.

[0022] Preferably, the number of conductor materials used for the initial twisting is 11 to 13.

[0023] Preferably, the conductor material has a diameter of 0.14-0.16 mm and a cross-sectional area of ​​0.45-0.55 mm. 2 .

[0024] Preferably, the twisting pitch of the initial twisting is 10-15 mm.

[0025] Preferably, the number of single strands used in the multiple twisting is 6 to 8 strands.

[0026] Preferably, the twisting pitch of the multiple twisting is 20-30 mm.

[0027] Preferably, the directions of the primary twisting and the secondary twisting are opposite.

[0028] The inventors have found that by controlling the strand lay direction and the re-twisted lay direction, and adjusting the twist pitch, the copper conductor's resistance to bending fatigue, tension and torsion can be improved, so that the mechanical properties of the re-twisted structure conductor are at least 5 times higher than those of the normal single-bundled conductor. This may be because when the conductor is bent, it bears tension outside the bending radius and extrusion inside the bending radius. The tension and extrusion pressure borne by the same bundle of strands vary with the position, which is a process of continuous compensation and offset. The smaller the pitch-to-diameter ratio, the more frequent this compensation is, and the more re-twisted layers there are, the more frequent this compensation will be. Therefore, the conductors of this type of re-twisted structure have more excellent resistance to bending and torsion, which is beneficial to increasing the service life of the conductor during the anti-bending process.

[0029] The copper conductor for robot equipment is prepared by the preparation process of the copper conductor for robot equipment.

[0030] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0031] 1. The present invention provides a copper conductor for robot equipment. By rationally designing the structure and selecting materials, the prepared copper conductor has excellent mechanical properties and high yield strength, indicating that the product has excellent bending and torsion resistance and long service life, and is very suitable for flexible cables used in robot equipment.

[0032] 2. The present invention improves the mechanical properties of the copper conductor while improving its flexibility and ductility by performing step-by-step annealing on the copper wire.

[0033] 3. The present invention immerses the annealed copper wire into a specific pickling solution, which can not only remove oxides and dirt on the surface of the copper wire, but also further improve the mechanical properties of the copper wire.

[0034] 4. The present invention can improve the bending fatigue resistance, tensile strength and torsion resistance of the copper conductor by controlling the strand lay direction and the re-twisted lay direction and adjusting the twist pitch, so that the mechanical properties of the re-twisted structure conductor are at least 5 times higher than those of the normal single-bundled conductor. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The raw materials described in the present invention are all commercially available, and are specifically as follows:

[0037] Copper wire, copper purity ≥99.95%, oxygen content <0.002%, diameter 0.15±0.01mm, cross-sectional area 0.5±0.02mm 2 , purchased from Qingdao Hancable Co., Ltd.

[0038] Tween 60, acid value ≤2.0mgKOH / g, hydroxyl value 81~96mgKOH / g, purchased from Yingxin Laboratory.

[0039] Example 1

[0040] This embodiment provides a preparation process of a copper conductor for robot equipment, the steps of which are: initially twisting the conductor material to form a single strand wire; and re-twisting the single strand wire to obtain a copper conductor.

[0041] The conductor material is a tinned copper conductor.

[0042] The preparation method of the tinned copper conductor comprises the following steps: annealing, pickling, tinning the copper wire in sequence, and then cleaning and drying the copper wire.

[0043] The specific conditions of the annealing are: 140° C. in the first stage, keep warm for 8 seconds; heat up to 290° C., keep warm for 8 seconds; heat up to 460° C., keep warm for 3 seconds, and cool to room temperature along with the furnace.

[0044] The specific steps of pickling are: immersing the annealed copper wire in a pickling solution at room temperature for 2 minutes, then taking it out, washing the pickling solution remaining on the surface with deionized water and drying it.

[0045] The solvent of the pickling solution is water, and the concentrations of the components are 15 g / L zinc chloride, 15 g / L ammonium chloride, 8 g / L sodium chloride, 15% hydrochloric acid (referring to the volume concentration of hydrochloric acid in the pickling solution is 15%), 2 g / L ethanolamine, and 0.3 g / L emulsifier.

[0046] The mass concentration of the hydrochloric acid is 37%.

[0047] The emulsifier is Tween 60.

[0048] The specific steps of tinning are: passing the copper wire into a tin furnace for tinning.

[0049] The temperature of the molten tin in the tin furnace is 350°C.

[0050] The aperture of the tinning mold in the tin furnace is 0.001 mm larger than the diameter of the annealed copper wire.

[0051] The tin liquid is molten tin.

[0052] The number of conductor materials used for the initial twisting is 12.

[0053] The twisting pitch of the initial twisting is 13 mm.

[0054] The number of single-strand wires used in the multiple-twisting is 7.

[0055] The twisting pitch of the multiple twisting is 25 mm.

[0056] The directions of the primary twisting and the secondary twisting are opposite.

[0057] Example 2

[0058] The difference between this embodiment and embodiment 1 is that the number of conductor materials used for the initial twisting is 13.

[0059] Example 3

[0060] The difference between this embodiment and embodiment 1 is that the number of single-strand wires used in the multiple-twisting is 8.

[0061] Comparative Example 1

[0062] The difference between this comparative example and Example 1 is that the specific conditions of the annealing are: heating to 460° C., keeping the temperature for 20 seconds, and cooling to room temperature along with the furnace.

[0063] Comparative Example 2

[0064] The difference between this comparative example and Example 1 is that the solvent of the pickling solution is water, and the concentrations of the components are 15 g / L zinc chloride, 15 g / L ammonium chloride, 8 g / L sodium chloride, 15% hydrochloric acid (referring to the volume concentration of hydrochloric acid in the pickling solution is 15%), and 0.3 g / L emulsifier.

[0065] The mass concentration of the hydrochloric acid is 37%.

[0066] Comparative Example 3

[0067] The difference between this comparative example and Example 1 is that the aperture of the tinning mold in the tin furnace is 0.05 mm larger than the diameter of the copper wire after annealing.

[0068] Comparative Example 4

[0069] The difference between this comparative example and Example 1 is that the number of conductor materials used in the initial twisting is 15.

[0070] Comparative Example 5

[0071] The difference between this comparative example and Example 1 is that the directions of the primary twisting and the secondary twisting are the same.

[0072] Performance Testing

[0073] Referring to the method in Wang Kun's paper "Research and Development and Performance Verification of Flexible Cables for Robots", the copper conductor was subjected to two rounds of flexure tests, drag chain tests, and 90° bending tests. The results of the two rounds of flexure tests were as follows: the mechanical life is 1 million times, the number of single specimens reaches the specified number of lifespans, and no conduction alarm occurs. The results of the drag chain test were as follows: the mechanical life is 10 million times, the number of single specimens reaches the specified number of lifespans, and no conduction alarm occurs. The results of the 90° bending test were as follows: the mechanical life is 1 million times, the number of single specimens reaches the specified number of lifespans, and no conduction alarm occurs. Each test records the on-off status of the copper conductor, the resistance change rate, and the conductor broken wire status. The results are shown in Table 1.

[0074] Table 1 Measurement results

[0075] According to statistics, the copper conductors for robot equipment prepared by Examples 1 to 3 of the present invention have exceeded the yield bending limit of the metal conductor. After two rounds of flexure test, drag chain test and 90° bending test, three mechanical life tests have been verified, and the resistance change rate is small, and no broken wire occurs. Comparative Example 1 did not perform step annealing, Comparative Example 2 did not add corrosion inhibitor ethanolamine, Comparative Example 3 tinning aperture is too large, resulting in a copper conductor diameter that is too large, Comparative Example 4 has too many copper conductors, and Comparative Example 5 has the same direction of initial twisting and re-twisting. The mechanical properties of the prepared copper conductor for robot equipment are poor and the yield strength is low. Therefore, the copper conductor for robot equipment prepared by the raw materials and methods described in this application has excellent mechanical properties, high yield strength, and has exceeded the yield bending limit of the metal conductor, indicating that the product has excellent anti-bending and torsion performance and a long service life.

[0076] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A process for preparing a copper conductor for robot equipment, characterized in that: The following steps are involved: The conductor material is initially twisted to form a single strand; The single strands are twisted and twisted to obtain; The directions of the initial twisting and the secondary twisting are opposite; the conductor material is a tinned copper conductor; the preparation method of the tinned copper conductor comprises the following steps: annealing, pickling, tinning, cleaning and drying the copper wire in sequence; the specific conditions of the annealing are: 130-150°C in the first stage, keeping warm for 5-10s; heating to 280-300°C, keeping warm for 5-10s; heating to 450-480°C, keeping warm for 1-5s, and cooling to room temperature with the furnace; the twist pitch of the initial twisting is 10-15 mm; the twist pitch of the secondary twisting is 20-30 mm.

2. The process for preparing the copper conductor for robot equipment according to claim 1, characterized in that: The conductor material has a diameter of 0.14-0.16 mm and a cross-sectional area of ​​0.45-0.55 mm 2 .

3. The process for preparing the copper conductor for robot equipment according to claim 1, characterized in that: The specific steps of pickling are: immersing the annealed copper wire in a pickling solution at room temperature for 1 to 3 minutes, then taking it out, washing the pickling solution remaining on the surface with deionized water and drying it.

4. The process for preparing a copper conductor for robot equipment according to claim 3, characterized in that: The solvent of the pickling solution is water, and the concentrations of the components in the pickling solution are: zinc chloride 10-20 g / L, ammonium chloride 10-20 g / L, sodium chloride 5-10 g / L, hydrochloric acid volume concentration 10-20%, ethanolamine 1-3 g / L, and emulsifier 0.1-0.5 g / L.

5. The process for preparing a copper conductor for robot equipment according to claim 1, characterized in that: The specific steps of tinning are: passing the copper wire into a tin furnace for tinning.

6. The process for preparing a copper conductor for robot equipment according to claim 1, characterized in that: The number of conductor materials used for the initial twisting is 11 to 13.

7. The process for preparing a copper conductor for robot equipment according to claim 1, characterized in that: The number of single strands used in the multiple twisting is 6 to 8 strands.

8. A copper conductor for robot equipment prepared according to the preparation process of the copper conductor for robot equipment according to any one of claims 1 to 7.

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