A method for tinning the surface of copper braid in cables

Abstract

The present invention provides a method for tinning the surface of a copper braid in a cable. The tinning method includes pickling, sandblasting, electrostatic spraying, high-temperature treatment, and cooling. In this embodiment, tin particles are evenly attached to the surface of the copper braid by electrostatic spraying. The high-temperature treatment and cooling steps solidify the tin particles to form a tin layer, effectively preventing deformation of the PTFE layer.

Description

Technical Field

[0001] The present invention relates to the field of cable technology, in particular to the field of high-speed cable preparation technology. Background Art

[0002] In the field of precision cable manufacturing, hot-dip tinning is a common surface treatment used to improve the oxidation resistance and weldability of the copper braid. This process involves dipping the cable assembly in a bent position into a 390°C molten tin bath for coating. This operating temperature affects the mechanical properties of polytetrafluoroethylene (PTFE), particularly PTFE with longitudinal pores, which can cause slight expansion. This bending process, combined with the deformation of the PTFE, can directly affect the cable's transmission speed performance.

[0003] In view of this, this application is filed. Summary of the Invention

[0004] The invention provides a tinning method for the surface of a copper braided layer in a cable, which effectively suppresses the thermal expansion and bending deformation of PTFE in a traditional tinning process.

[0005] The present invention provides a tinning method for the surface of a copper braided layer in a cable, wherein the cable comprises an inner conductor, a PTFE layer, a copper braided layer and a tin layer arranged from the inside out;

[0006] The tinning method comprises the following steps:

[0007] Step 1: providing a tinning device for the surface of the copper braid layer in the cable;

[0008] Step 2, pickling: pickling the copper braided layer to remove surface oil stains of the copper braided layer;

[0009] Step 3, sandblasting: sandblasting the pickled copper braid layer to increase the surface roughness of the copper braid layer;

[0010] Step 4, electrostatic spraying: using the tin plating device to form a tin particle layer on the surface of the copper braided layer by electrostatic spraying;

[0011] Step 5, high temperature treatment: using the tin plating device to perform high temperature treatment on the tin particle layer to melt the tin particles;

[0012] Step 6: Cooling: Cooling is performed at a certain cooling rate to form a tin layer.

[0013] Furthermore, the reagents used for pickling in step 2 include one or more of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, phosphoric acid, sulfamic acid, citric acid, and acetic acid.

[0014] Furthermore, in step 4, the specific steps of forming a tin particle layer on the surface of the copper braided layer by electrostatic spraying include:

[0015] Step 4.1, applying a negative charge to the tin particles, and making the copper braid layer positively charged or grounded;

[0016] Step 4.2: The charged tin particles are uniformly deposited on the surface of the copper braided layer under the action of the tin plating device.

[0017] Furthermore, in step 4.1, applying negative charge to the tin particles specifically comprises: using corona discharge to make the tin particles negatively charged.

[0018] Furthermore, the temperature of the high temperature treatment in step 5 is 270-290°C;

[0019] The high temperature treatment is performed under an inert gas atmosphere.

[0020] Furthermore, the cooling step in step 6 is performed under an inert gas atmosphere.

[0021] Furthermore, the tinning device includes a spray gun module, a heating module, a quartz tube and a winding module;

[0022] wherein the quartz tube is arranged around the upstream of the cable;

[0023] The heating modules are arranged above and below the quartz tube;

[0024] The spray gun module is arranged at one side of the quartz tube inlet, and is used to spray the negatively charged tin particles into the quartz tube;

[0025] The winding module is arranged downstream of the cable, and is used to receive the cable and ground the copper braided layer of the cable.

[0026] Furthermore, the spray gun module is also used to spray inert gas into the interior of the quartz tube;

[0027] The spray gun module includes a spray gun head, an inert gas storage tank and a tin particle storage tank;

[0028] An inert gas storage tank and a tin particle storage tank are respectively connected to the spray gun head;

[0029] The spray gun head is arranged around the cable and is communicated with the inlet of the quartz tube for spraying tin particles and inert gas into the quartz tube.

[0030] Furthermore, the spray gun head is annular and includes a first nozzle and a second nozzle; the first nozzle is connected to the inert gas storage tank; the second nozzle is connected to the tin particle storage tank;

[0031] The first nozzle and the second nozzle are both opposite to the inlet end of the quartz tube, and the first nozzle is arranged on the periphery of the second nozzle.

[0032] Furthermore, the quartz tube is conical, having a first end face arranged at the inlet end and a second end face arranged at the outlet end, the diameter of the first end face is larger than the diameter of the second end face; along the direction from the first end face to the second end face, the diameter of the quartz tube gradually decreases.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] (1) The present application uses electrostatic spraying to evenly distribute tin particles on the surface of the copper braided layer, thus avoiding the bending operation of the cable.

[0035] (2) The maximum temperature of the high-temperature treatment in this application is only 270-290°C, which is much lower than 390°C. This temperature will not cause the mechanical properties of PTFE to deteriorate or expand, thereby avoiding the deformation of PTFE.

[0036] (3) The quartz tube in the tinning tooling of the present application not only effectively protects the upper and lower lamp groups, but also its conical shape promotes the uniform distribution of the tin liquid particles inside.

[0037] (4) The inert gas ejected from the spray gun in the tinning tool of the present application effectively inhibits the oxidation of tin particles before they are attached. The ejected inert gas cooperates with the quartz tube to discharge excess tin particles that are not attached from the quartz tube, thus preventing them from accumulating inside the quartz tube. At the same time, the inert gas can also cool the cable during the cooling step. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 paying any creative work.

[0039] Figure 1 This is a schematic diagram of the cable structure cross-section of this embodiment;

[0040] Figure 2 Schematic diagram of the tin plating process implemented in this paper;

[0041] Figure 3 This is a schematic diagram of the tinning tooling structure of this embodiment;

[0042] Figure 4 is a schematic cross-sectional view along dotted line A;

[0043] Figure 5 It is a schematic cross-sectional view along the dotted line B. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] Figure 1 It is a cross-sectional diagram of the cable structure. Figure 1 As shown, cable 10 comprises, from the inside out, an inner conductor 101, a PTFE layer 102, a copper braid 103, and a tin layer 104. PTFE layer 102 is hollow and has multiple through-holes 105. Preferably, through-holes 105 accommodate other conductors. Furthermore, copper braid 103 is formed by cross-weaving copper flat wires through an aircraft film.

[0046] like Figure 1 As shown, a tin layer is provided on the outer layer of the copper braided layer 103. The existing process uses a hot dip process, that is, the cable 10 is dipped in a 390°C high-temperature molten tin bath to perform the coating operation. However, due to the influence of high temperature and bending, the electrical performance will be degraded.

[0047] Figure 2 The tinning process of this embodiment is shown. Optionally, the tinning process is used to Figure 1 The cable 10 is tinned; Figure 2 As shown, the tinning process of this embodiment includes the following steps:

[0048] Step 1: providing a tinning device for the surface of the copper braid layer in the cable;

[0049] Step 2, pickling: pickling the copper braided layer 103 to remove oil stains on the surface of the copper braided layer 103;

[0050] Preferably, the reagent used for pickling includes one or more of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, phosphoric acid, sulfamic acid, citric acid, and acetic acid.

[0051] Preferably, the pickling time of this embodiment is 3-5 minutes. Preferably, the pickling is achieved by passing the cable through the pickling device.

[0052] Step 3, sandblasting: sandblasting the pickled copper braid layer 103 to increase the surface roughness of the copper braid layer 103 and enhance the adhesion of the tin layer.

[0053] Preferably, the sandblasting is performed using a sandblasting device. Specifically, in this embodiment, corundum is used for sandblasting, and the blasting mesh size is 10-120 meshes.

[0054] Step 4, electrostatic spraying: using the tin plating device to form a tin particle layer on the surface of the copper braided layer by electrostatic spraying;

[0055] Preferably, the particle size of the tin particles used in this embodiment is 10-15 μm.

[0056] Preferably, the electrostatic spraying steps are specifically as follows:

[0057] Step 4.1, applying a negative charge to the tin particles, and making the copper braid layer positively charged or grounded;

[0058] Step 4.2: The charged tin particles are uniformly deposited on the surface of the copper braided layer under the action of the tin plating device.

[0059] Preferably, in step 4.1, the tin particles are negatively charged by corona discharge; and the copper braided layer 103 is grounded.

[0060] Step 5, high temperature treatment: using the tin plating device to perform high temperature treatment on the tin particle layer to melt the tin particles;

[0061] Preferably, the temperature of the high temperature treatment is 270-290° C. More preferably, the temperature of the high temperature treatment is 285-290° C. This temperature can quickly melt the tin particles without affecting the PTFE layer 102 .

[0062] Preferably, the high temperature treatment is performed in an inert gas atmosphere to prevent the growth of an oxide layer on the surface of the tin layer 104 .

[0063] Step 6: Cooling: Cooling is performed at a certain cooling rate to form a tin layer 104 .

[0064] Preferably, the cooling step is performed under an inert gas atmosphere to avoid the growth of an oxide layer on the surface of the tin layer 104. Further optionally, the cooling step is performed by the tin plating device.

[0065] Figure 3 Shown for the above Figure 2 Schematic diagram of the tinning device structure of the tinning process. Figure 3 As shown, the tinning device includes a spray gun module, a heating module, a quartz tube 40 and a winding module 60.

[0066] The spray gun module, quartz tube 40, and reel module 60 are arranged in sequence along the horizontal direction of the cable 10. The quartz tube 40 is positioned upstream of the cable 10, and the heating modules are positioned above and below the quartz tube 40. The reel module 60 is positioned downstream of the cable 10 to reel the cable.

[0067] The spray gun module includes a spray gun head 20, an inert gas storage tank (not shown), and a tin granule storage tank 50. The inert gas storage tank stores inert gas, while the tin granule storage tank stores tin granules. The spray gun module is located near the inlet of the quartz tube 40 and is used to spray the tin granules and inert gas into the quartz tube 40. Specifically, the spray gun head 20 is positioned around the cable 10 and communicates with the inlet of the quartz tube 40, spraying the tin granules and inert gas into the quartz tube 40.

[0068] Specifically, the tin particle storage tank is communicated with the spray gun head 20 , and the inert gas storage tank is also communicated with the spray gun head 20 .

[0069] Preferably, the inert gas in this embodiment can be nitrogen or helium.

[0070] Preferably, this embodiment further includes a high-voltage generator (not shown in the figure), one end of which is connected to the spray gun module, specifically, to the spray gun head 20; the high-voltage generator causes the tin particles to carry a negative charge before being sprayed out by corona discharge.

[0071] Figure 4 Shown along the dotted line A ( Figure 3 As shown in the cross-sectional view of Figure 4 As shown, in this cross-section, the spray gun head 20 is annular and includes a first nozzle 201 and a second nozzle 202. Preferably, the spray gun head 20 is placed horizontally, and the first nozzle 201 and the second nozzle 202 are both located on the same annular side end surface of the annular shape, which is the side facing the inlet of the quartz tube 40, and the first nozzle 201 is located on the periphery of the second nozzle 202. Specifically, the cable 10 passes through the annular hollow hole of the spray gun head 20, and the cable 10 extends along the axis of the annular shape, that is, the cable 10 passes through the center of the annular shape. The multiple first nozzles 201 are evenly distributed circumferentially along the annular side end surface of the spray gun head 20, and the multiple second nozzles 202 are evenly distributed circumferentially along the annular side end surface of the spray gun head 20.

[0072] The first nozzle 201 is connected to the inert gas storage tank and is used to inject inert gas into the interior of the quartz tube 40. This prevents oxidation of the tin particles while also removing excess unattached tin particles from the quartz tube 40, effectively preventing excess tin particles from being deposited inside the quartz tube 40. Simultaneously, the tin layer can also be cooled during the cooling step.

[0073] The second nozzles 202 are connected to the tin particle storage tank and are used to spray negatively charged tin particles into the quartz tube 40. The circumferentially uniformly distributed second nozzles 202 can allow the tin particles to be deposited more evenly around the cable.

[0074] Preferably, the first nozzle is circular in shape; the second nozzle is rectangular in shape, the size of the second nozzle is larger than that of the first nozzle, and extends along the circumferential direction, which can prevent tin particles from clogging the second nozzle.

[0075] The quartz tube 40 is a hollow, conical tube positioned horizontally, with the cable passing through the center of the cone. The tube 40 includes a first end surface at the inlet and a second end surface at the outlet. The diameter of the first end surface is larger than that of the second end surface; the diameter of the tube 40 gradually decreases from the first end surface to the second end surface.

[0076] Since the tin particles move in the direction of travel (i.e. Figure 3 (From the horizontal direction to the right), the concentration of tin particles gradually decreases as they are continuously absorbed by the copper braid of the cable. The conical shape of the quartz tube 40 ensures that the density of the tin particles inside it is basically the same at each horizontal cross section, that is, the density of the tin particles at the first end cross section is basically the same as that at the second end cross section, thus ensuring the uniformity of the electrostatic spraying. Figure 3 The heating modules are horizontally arranged above and below the quartz tube 40, and are used to create a temperature field inside the quartz tube 40 so that the tin particles attached to the surface of the copper braided layer melt into tin liquid. Specifically, the heating modules include an upper lamp group 301 and a lower lamp group 302. Both the upper lamp group 301 and the lower lamp group 302 are rectangular structures. The upper lamp group 301 is arranged directly above the quartz tube 40, and the lower lamp group 302 is arranged directly below the quartz tube 40. The upper lamp group 301 includes a reflector and a linear lamp. The linear lamp is arranged below the reflector, and the reflector is used to reflect the heat radiation generated by the linear lamp to the cable. The lower lamp group 302 also includes a reflector and a linear lamp. The linear lamp is arranged above the reflector, and is used to reflect the heat radiation generated by the linear lamp to the cable.

[0077] In the upper light group 301 and the lower light group 302, there are multiple linear lights, and adjacent linear lights are arranged in parallel and equidistantly. A plurality of parabolic reflection grooves are provided on the side of the reflection plate facing the linear lights. The reflection grooves are opposite to the linear lights and are used to reflect the light of the linear lights in parallel to the cable. The reflection plate and the linear lights are both arranged horizontally, and the linear lights are perpendicular to the cable.

[0078] Preferably, the linear lamps of the upper lamp group 301 and the lower lamp group 302 are all halogen lamps.

[0079] The winding module 60 is disposed downstream of the cable 10. After the molten tin liquid is solidified again to form a tin layer after high temperature treatment, the cable 10 is wound by the winding module 60.

[0080] Preferably, the reel module 60 is grounded so that the copper braid of the cable 10 is grounded.

[0081] Figure 5 A schematic cross-sectional view along the dotted line B is shown. Figure 5 As shown, the quartz tube 40 consists of an upper portion 401 and a lower portion 402. Upper portion 401 is the upper half of the tube, while lower portion 402 is the lower half of the tube. Together, they form a hollow conical shape. The upper portion 401 has an Ω-shaped vertical cross-section, comprising a first body and first and second protrusions located on either side of the first body. The lower portion 403 has an Ω-shaped vertical cross-section, comprising a second body and third and fourth protrusions located on either side of the second body. The first and second bodies form the conical sidewalls of the quartz tube 40.

[0082] See again Figures 4 and 5 The tinning device further includes a circular bracket 703 and a base. The circular bracket 703 is arranged on the base, and the spray gun module, heating module, and quartz tube 40 are all arranged on the circular bracket 703.

[0083] Specifically, the quartz tube 40 is fixed to the circular bracket 703 via a first cross arm 801 and a second cross arm 802. One end of the first cross arm 801 is fixedly connected to the circular bracket 703, and the other end has a first interface 8011. The first interface 8011 is C-shaped and is used to clamp the stacked first and third bumps. Correspondingly, one end of the second cross arm 802 is fixedly connected to the circular bracket 703, and the other end has a second interface 8021. The second interface 8021 is C-shaped and is used to clamp the stacked second and fourth bumps. Preferably, it also includes two screws (not shown in the figure) and two nuts (not shown in the figure): the first screw sequentially passes through the first interface, the first bump, and the third bump, and the clamping force is adjusted by the first nut. Similarly, the second screw sequentially passes through the second interface, the second bump, and the fourth bump, and the clamping force is adjusted by the second nut.

[0084] The upper light assembly 301 is secured by a first vertical rod 701 and a circular bracket 703, while the lower light assembly 302 is secured by a second vertical rod 702 and a circular bracket 703. One end of the first vertical rod 701 is fixedly connected to the circular bracket 703, and the other end is fixedly connected to the upper light assembly 301. Correspondingly, one end of the second vertical rod 702 is fixedly connected to the circular bracket 703, and the other end is fixedly connected to the lower light assembly 302.

[0085] The base includes support legs 901 and crossbeams 902. The support legs 901 are arranged vertically to support the circular bracket 703. Specifically, the upper ends of the support legs 901 are fixed to the circular bracket 703, and the lower ends are placed on the horizontal ground. The support legs 901 are fixed together by crossbeams 902.

[0086] Preferably, there are two circular brackets 703, such as Figure 3 The cables are respectively arranged at the inlet and outlet ends of the quartz tube 40, and the cables are arranged at the center of the circular bracket 703. There are four supporting legs 901, which are supported below the two circular brackets 703 to form a rectangular frame.

[0087] Method of using the tinning device of the present invention:

[0088] According to the running direction of the cable 10 (from upstream to downstream), the pickling device, the sandblasting device and the tinning device are arranged in sequence.

[0089] Step 2: pickling by a pickling device;

[0090] Step 3: sandblasting by a sandblasting device;

[0091] Step 4: Turn on the spray gun module and the high-voltage generator, and introduce tin particles and inert gas into the quartz tube to form a tin particle layer on the surface of the copper braided layer;

[0092] Step 5: Turn off the high-voltage generator and the tin particles, introduce only inert gas, turn on the heating module, and perform high-temperature treatment on the tin particle layer to melt the tin particles.

[0093] Step 6: Turn off the heating module and only introduce inert gas to melt the tin particles and cool them to form a tin layer.

[0094] It should be noted that the tin layer of the cable may also include other layers, such as an isolation tape, a sheath, a fiber braided layer, etc.

[0095] The terms "equal," "same," or "equal" disclosed in the present invention must take into account the distribution of engineering parameters, with an error distribution within ±30%; the definition of "parallel" between two line segments or two straight lines is that the angle between the two line segments or two straight lines is less than or equal to 45 degrees; the definition of "perpendicular" between two line segments or two straight lines is that the angle between the two line segments or two straight lines is within the range of [60, 120] degrees; the definition of "phase mismatch" also needs to take into account the distribution of engineering parameters, with an error distribution of the degree of mismatch within ±30%. In addition, in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article, or apparatus. Without further constraints, an element defined by the phrase "comprises a..." does not preclude the existence of additional identical elements in the process, method, article or apparatus that includes the element.

[0096] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0097] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for tinning the surface of a copper braided layer in a cable, characterized in that: The cable comprises an inner conductor, a PTFE layer, a copper braid layer and a tin layer arranged from the inside out; The tinning method comprises the following steps: Step 1: providing a tinning device for the surface of the copper braid layer in the cable; Step 2, pickling: pickling the copper braided layer to remove surface oil stains of the copper braided layer; Step 3, sandblasting: sandblasting the pickled copper braid layer to increase the surface roughness of the copper braid layer; Step 4, electrostatic spraying: using the tin plating device to form a tin particle layer on the surface of the copper braided layer by electrostatic spraying; Step 5, high temperature treatment: using the tin plating device to perform high temperature treatment on the tin particle layer to melt the tin particles; Step 6: Cooling: Cooling at a certain cooling rate to form a tin layer; In step 5, the temperature of the high temperature treatment is 270-290°C; The high temperature treatment is performed under an inert gas atmosphere.

2. The tinning method for the surface of the copper braided layer in the cable according to claim 1, characterized in that: The reagents used for pickling in step 2 include one or more of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, phosphoric acid, sulfamic acid, citric acid, and acetic acid.

3. The tinning method for the surface of the copper braided layer in the cable according to claim 1, characterized in that: In step 4, the specific steps of forming a tin particle layer on the surface of the copper braided layer by electrostatic spraying include: Step 4.1, applying a negative charge to the tin particles, and making the copper braid layer positively charged or grounded; Step 4.2: The charged tin particles are uniformly deposited on the surface of the copper braided layer under the action of the tin plating device.

4. The method for tinning the surface of the copper braided layer in the cable according to claim 3, characterized in that: In the step 4.1, applying negative charge to the tin particles specifically comprises: applying negative charge to the tin particles by corona discharge.

5. The tinning method for the surface of the copper braided layer in the cable according to claim 1, characterized in that: The cooling step in step 6 is performed under an inert gas atmosphere.

6. The tinning method for the surface of the copper braided layer in the cable according to claim 1, characterized in that: The tinning device includes a spray gun module, a heating module, a quartz tube and a winding module; wherein the quartz tube is arranged around the upstream of the cable; The heating modules are arranged above and below the quartz tube; The spray gun module is arranged at one side of the quartz tube inlet, and is used to spray the negatively charged tin particles into the quartz tube; The winding module is arranged downstream of the cable, and is used to receive the cable and ground the copper braided layer of the cable.

7. The method for tinning the surface of the copper braided layer in the cable according to claim 6, characterized in that: The spray gun module is also used to spray inert gas into the interior of the quartz tube; The spray gun module includes a spray gun head, an inert gas storage tank and a tin particle storage tank; An inert gas storage tank and a tin particle storage tank are respectively connected to the spray gun head; The spray gun head is arranged around the cable and is communicated with the inlet of the quartz tube for spraying tin particles and inert gas into the quartz tube.

8. The method for tinning the surface of the copper braided layer in the cable according to claim 7, characterized in that: The spray gun head is annular and includes a first nozzle and a second nozzle; the first nozzle is connected to the inert gas storage tank; the second nozzle is connected to the tin particle storage tank; The first nozzle and the second nozzle are both opposite to the inlet end of the quartz tube, and the first nozzle is arranged on the periphery of the second nozzle.

9. The method for tinning the surface of the copper braided layer in the cable according to claim 7, characterized in that: The quartz tube is conical in shape and has a first end face arranged at the inlet end and a second end face arranged at the outlet end. The diameter of the first end face is larger than the diameter of the second end face. The diameter of the quartz tube gradually decreases along the direction from the first end face to the second end face.

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