Method for manufacturing a metal terminal, an assembly comprising a metal terminal and an electrical conductor

Abstract

Method and machine for manufacturing a metal terminal, assembly comprising a metal terminal and an electrical conductor. Method for manufacturing a metal terminal (18) at one end (12) of a single-strand or multi-strand electrical conductor (10), comprising the following steps: S10) positioning the end of the conductor in an enclosure (110) of an additive manufacturing machine (100); and S20) manufacturing the terminal (18) directly onto an external surface (16) of the end of the electrical conductor by additive manufacturing. Metal terminal manufacturing machine, adapted for carrying out this method, and assembly comprising a metal terminal and an electrical conductor to which the terminal is fixed. Figure for the abstract: Fig. 2.

Description

Title of the invention: Method for manufacturing a metal terminal, an assembly comprising a metal terminal and an electrical conductor technical field

[0001] The invention relates to the field of manufacturing and fixing metal terminals at the end of electrical conductors, in particular at the end of small diameter electrical conductors. Previous technique

[0002] Connecting electrical conductors to ensure the flow of an electric current or to bring the two conductors to the same potential is an essential operation for the functioning of most electrical systems. In many cases, to ensure the quality of the electrical contact, this connection is made by means of metal terminals, in particular pairs of male and female metal terminals of complementary shapes, arranged to ensure reliable electrical contact between the male and female terminals.

[0003] However, the use of electrical terminals in turn creates the need to secure the terminal to the electrical conductor. This securing is usually achieved by crimping: the terminal has a tubular portion into which the end of the conductor can be inserted. The terminal is secured by crimping the tubular portion onto the end of the conductor.

[0004] However, this design requires the use of a terminal with a tubular end. From an industrial point of view, this imposes considerable constraints on the manufacturing process that can be used to produce an electrical conductor to one end of which a metal terminal is attached.

[0005] The terminal can also be fixed to the conductor by welding or brazing, but these fixing methods are difficult to implement with small diameter conductors.

[0006] Therefore, there is a need for a manufacturing process for manufacturing a metal terminal and attaching it to one end of an electrical conductor, in particular a conductor of small diameter, and without the process requiring the terminal to have a tubular end into which the end of the conductor can be inserted. Description of the invention

[0007] To meet this need, according to the present disclosure, a method for manufacturing a metallic terminal at one end of an electrical conductor is proposed. single-strand or multi-strand. This process includes the following operations:

[0008] S10) position the end of the conductor in an enclosure of an additive manufacturing machine, and

[0009] S20) fabricate the terminal directly on an external surface of the end of the electrical conductor by additive manufacturing.

[0010] The method thus defined is naturally applicable not only to the manufacture of a single metal terminal on one end of an electrical conductor, but also to the parallel manufacture of a plurality of terminals on the respective ends of different electrical conductors. These conductors may advantageously all be part of the same multi-conductor electrical wire.

[0011] Advantageously, because the terminal is formed directly on said external surface by additive manufacturing, the shape of the terminal is unrestricted, and it is not necessary to provide a tubular part that can be crimped onto the end of the conductor. Furthermore, since the terminal is manufactured by additive manufacturing directly on the external surface, it is intimately fixed to the conductor and forms an integral part of it from the moment of manufacture.

[0012] In one embodiment, the positioning (or placement) operation S10 of the conductor end includes an operation S12 consisting of passing the conductor end, which has said external surface, through a retaining panel. During the manufacturing operation S20, the conductor end is held in a fixed position (relative to the enclosure of the additive manufacturing machine) by the retaining panel.

[0013] By passing and holding the end of the conductor through the retaining panel, lateral and longitudinal support of the end of the conductor is ensured, which allows the terminal manufacturing operation to be carried out.

[0014] The panel may, in particular, form part of a wall of the enclosure, especially the back wall of the enclosure in which the terminal is manufactured. Thus, most of the conductor remains outside the enclosure in which the terminal is manufactured by additive manufacturing.

[0015] In one embodiment, during the S20 manufacturing operation, the contents of the enclosure have a different composition from the atmosphere surrounding the additive manufacturing machine, and during the S20 operation, the retaining panel helps to separate the contents of the enclosure from the atmosphere surrounding the additive manufacturing machine.

[0016] The panel is preferably arranged horizontally during the manufacturing step (S20).

[0017] The panel may be flat in shape, but not necessarily.

[0018] In one embodiment, the method further comprises an S30 operation consisting of extracting the end of the conductor to which the terminal is attached from the retaining panel, by passing it through the retaining panel.

[0019] In one embodiment, operation S10 includes an operation S14 consisting of removing a portion of the conductor end, so as to expose said external surface. This end portion is a part of the conductor end.

[0020] Step S14 of removing the end portion of the conductor can be done before or after step S12 of driver placement by passing it through the retaining panel.

[0021] Different additive manufacturing processes can be used for manufacturing the terminal.

[0022] In one embodiment, the manufacturing operation S20 is carried out by electrolytic deposition. The conductor is then used as an electrode.

[0023] In other embodiments, the manufacturing operation S20 is carried out by melting metal powders. This operation can notably be carried out by powder bed fusion (laser fusion or electron beam fusion), or by the 'directed energy deposition' process.

[0024] Some of the processes that can be implemented use a nozzle capable of producing a metallic coating, which is part of the additive manufacturing machine. A 'nozzle capable of producing a metallic coating' here refers to a nozzle that projects, or at least releases, a fluid and / or particles onto the surface of a substrate positioned opposite the nozzle, thereby forming a metallic deposit on the substrate surface. The formation of this deposit most often requires the use of additional means besides the nozzle. For example, in the case of additive manufacturing by electrolytic deposition, the formation of the deposit requires that the chamber be able to accommodate the electrolytic bath, that a voltage generator be present, etc. The nozzle can be of any shape.

[0025] In embodiments using a nozzle suitable for producing a metallic coating, the positioning operation S10 preferably includes the positioning of the end of the electrical conductor in the working volume of the nozzle.

[0026] This disclosure also includes an assembly comprising a metal terminal and a single-strand or multi-strand electrical conductor, the terminal being produced by additive manufacturing directly on an external surface of one end of the conductor.

[0027] The terminal may in particular have been manufactured at the end of the conductor using one of the processes described above.

[0028] In one embodiment, the external surface on which the terminal was manufactured extends in a plane perpendicular to an axis of the end of the conductor.

[0029] Advantageously, the additive manufacturing process makes it possible to give all kinds of shapes to the terminal manufactured at the end of the conductor.

[0030] Most often, the diameter of the terminal is no more than 2 conductor diameters, or even 1.5 conductor diameters. It may also be less than or equal to the diameter of the conductor.

[0031] Advantageously, the process according to this disclosure can be applied to electrical conductors of very small diameters, for example, conductors with a diameter not exceeding 400 µm, or even 200 µm, or even 100 µm. But the process can even be applied to electrical conductors of extremely small diameters, for example, conductors with a diameter not exceeding 50 µm, or even 25 µm, or even 15 µm.

[0032] The process according to this disclosure allows the manufacture of terminals in various materials. The terminal material can, in particular, be copper, ruthenium, palladium or gold.

[0033] By extension, this disclosure also includes an electrical connector, comprising a housing in which is fixed at least one assembly comprising a terminal and an electrical conductor conforming to this disclosure.

[0034] This disclosure also includes a multi-conductor electrical wire, in which each conductor among a plurality of conductors is attached to a metal terminal and together with it constitutes an assembly comprising a metal terminal and an electrical conductor according to this disclosure.

[0035] A second objective of the present disclosure is to propose a machine for manufacturing one (or at least one) metal terminal at the end of one (or at least one) single-strand or multi-strand electrical conductor; the machine comprising a holding panel; the machine comprising a manufacturing enclosure (110); and the machine being configured to allow the end of the electrical conductor to be passed through a hole in the holding panel and to hold an external surface of the end of the electrical conductor in a fixed position in the manufacturing enclosure, using the holding panel, and, the end of the electrical conductor being thus held in a fixed position in the manufacturing enclosure, to manufacture the terminal directly on said surface by additive manufacturing.

[0036] This manufacturing machine can be configured to allow the implementation of each of the variants of the manufacturing process presented above.

[0037] It can also be configured to allow the parallel manufacturing of a plurality of terminals on the respective ends of a plurality of electrical conductors. Brief description of the drawings

[0038] [Fig.1] Fig.1 is a schematic perspective view of a metal terminal manufacturing system constituting an embodiment of the present disclosure;

[0039] [Fig.2] The [Fig.2] is a schematic partial cross-sectional view of the metal terminal manufacturing system of the [Fig.1];

[0040] [Fig. 3A-3B] Figures 3A and 3B are schematic partial cross-sectional views of a single-strand conductor in the metal terminal manufacturing system shown in Figures 1 and 2, respectively before and during the cutting of a section of the conductor end;

[0041] [Fig.4] The [Fig.4] is a flowchart showing the manufacturing steps of a single-strand conductor, in an implementation mode of the present disclosure;

[0042] [Fig. 5] [Fig. 5] is a schematic side view of an assembly comprising an electrical conductor and a metal terminal attached to its end, in accordance with this disclosure; and

[0043] [Fig.6] The [Fig.6] is a schematic perspective view of an electrical connector and a multi-conductor electrical wire conforming to this disclosure.

[0044] Note: In some parts of the figures the proportions have not been respected, in order to represent more visibly the characteristics of the machine and the manufacturing process shown.

[0045] Description of embodiments

[0046] With reference to Figures 1 and 2, a machine 100 for manufacturing metal terminals at the ends of single-strand or multi-strand electrical conductors by additive manufacturing will now be presented. The additive manufacturing machine 100 is specially adapted and modified in accordance with this disclosure to enable the manufacturing of metal terminals at the ends of single-strand or multi-strand electrical conductors.

[0047] The machine chosen to constitute the system is a machine chosen according to the diameter of the conductors at the end of which we want to form metallic terminals.

[0048] Advantageously, additive manufacturing machines enabling the manufacture of parts with dimensions on the order of a few tens of micrometers (pm), or even micrometers, are commercially available and can be used.

[0049] The additive manufacturing machine 100 includes an enclosure 110 designed for additive manufacturing. The bottom of this enclosure 110 is mainly formed by a retaining panel 115. This retaining panel 115 is configured to allow conductors to pass through the panel.

[0050] To simplify the figures, in the embodiment presented here, the system allows the fabrication of only one terminal, at the end of a single conductor. It is understood, however, that in other embodiments, the system can be configured to allow the parallel fabrication of several terminals at the ends of several conductors.

[0051] Similarly, although the conductor 10 shown in the figures is a single-strand conductor, this disclosure is applicable to multi-strand conductors. Where appropriate, suitable measures must be taken to ensure the sealing of the retaining panel 115 at the hole(s) through which the conductor(s) pass.

[0052] The system 100 includes in particular a 3-axis (x,y,z) displacement system consisting of a two-axis (x,y) displacement table 120 allowing the manufacturing enclosure 110 to be moved horizontally, in an xy plane, with an accuracy on the order of pm, and a vertical displacement subsystem 130, allowing a manufacturing nozzle 150 to be moved along the vertical z direction.

[0053] The movement system (table 120 and subsystem 130) is connected to and controlled by a computer 160.

[0054] The manufacturing nozzle 150 is a nozzle configured to allow the deposition of metallic material onto a conductive substrate.

[0055] In the embodiment presented, the deposition is carried out by electrolysis. The additive manufacturing machine 100, and in particular the nozzle 150, includes a deposition fluid supply device known per se, of which only a small part is shown in the figures, namely the supply of the nozzle 150 with deposition fluid ([Fig.2], arrow B).

[0056] In this embodiment, the deposition fluid 152 is a copper sulfate (CuSO4) solution. The additive manufacturing machine 100 is configured to allow copper deposition at the end of the conductor 10. The deposition takes place in a concentrated sulfuric acid bath (pH 3), which constitutes the internal environment 102 of the manufacturing chamber 140. Naturally, the electrolytic bath and the deposition fluid may have other compositions, as long as these allow for metallic deposition on the external surface of the conductor 10 by electrolysis.

[0057] To ensure copper deposition by reducing Cu2+ ions and thus depositing them as copper Cu at the end of conductor 10, a voltage is applied by a voltage source V. The positive terminal of this source is connected to the positive input of an operational amplifier A, and the negative terminal is connected to conductor 10 and to ground. The support panel 115 is electrically insulating. The negative input of operational amplifier A is connected to a reference electrode Er, and its output is connected to an auxiliary electrode or counter electrode CE.

[0058] During the manufacturing of the terminal by electrolysis, the copper ions of the deposition fluid 152 are transformed into copper (metal) and are deposited. Initially, they are deposited on an external surface 16 formed at the end 12 of the conductor 10. Then, as the terminal is manufactured, layer by layer, they are deposited on the upper layer of the terminal, that is to say on the surface of the last layer formed.

[0059] During manufacturing, the conductor, and then the terminal itself, acts as a working electrode. The voltage source V, the operational amplifier A, and the electrodes Er and CE together form a potentiostat. In a manner known per se, this potentiostat allows the conductor 10, acting as the working electrode, to be brought to a constant potential relative to the reference electrode Er, thus enabling copper deposition by electrolysis.

[0060] . In the present embodiment, panel 115 is flat. However, the present Disclosure includes the case where the retaining panel has any shape. The only requirement it must meet is to allow the passage of the conductor end and to retain that end during the additive manufacturing of the terminal.

[0061] Furthermore, in the present embodiment the panel 115 also advantageously constitutes a sealed wall separating the medium 102 (the electrolytic sulfuric acid bath) in which the manufacturing of the terminal is carried out from the surrounding atmosphere 104.

[0062] To ensure that the conductor 10 is held in place during manufacturing, the panel 115 is drilled with at least one hole 112. This hole 112 is sized to allow the conductor 10 to pass through the panel. Preferably, as in the present embodiment, it is more precisely arranged and sized to remain watertight when the end 12 of the conductor is positioned in the hole.

[0063] The additive manufacturing machine 100 further comprises a cutting blade 170. This cutting blade is fixed to the end of an arm 172, itself rigidly fixed to the nozzle 150. Being fixed on the nozzle 150, the blade 170 can thus be moved relative to the enclosure 140, and therefore relative to the end 12 of the conductor 10 passing through the panel 115, using the movement system of the additive manufacturing machine 100.

[0064] An example of implementation of a method for manufacturing a metal terminal at the end of a conductor, in accordance with this disclosure, will now be presented in relation primarily to Figs. 3A, 3B and 4.

[0065] In a first step S10, the end 12 of the conductor 10 is positioned or placed in the enclosure 110 of the machine 100. The end 12 is placed in this enclosure such that, at the end of step S14 described below, the external surface 16 on which the terminal 18 will be formed is placed in the working volume of the 150 nozzle.

[0066] In some embodiments, in particular the one shown below, an end portion (a section 14) of the conductor end is eliminated after the conductor end has been placed in the enclosure, but before the terminal is manufactured.

[0067] Naturally, in order for the metal terminal 18 to be fixed in the most solid and durable way possible to the conductor 10, it is preferable that the external surface of the latter (surface 16), on which the terminal is manufactured, be as free as possible from any impurity.

[0068] Several methods are conceivable to obtain this result, depending on the dimensions of the conductor 10. The end surface can thus be cleaned by mechanical actions (brushing), chemical actions (soaking in cleaning baths), etc.

[0069] In the present embodiment, the chosen method consists of performing an operation S14 which involves removing a portion of the conductor's end (a conductor end section) so as to expose a surface of the conductor. This surface thus becomes the external surface 16 of the conductor on which the terminal 18 will be formed by additive manufacturing. This operation is shown in Figs. 3A and 3B.

[0070] Fig.3A represents the end 12 of the conductor 10 passed through the hole 112 of the retaining panel 115. The axis C of the end 12 of the conductor is oriented vertically.

[0071] In Fig. 3A, a portion of the cutting blade 170 is approaching the conductor 10 by moving horizontally along arrow F. More precisely, the blade 170 moves along the horizontal, flat upper surface P of the retaining panel 115, following this plane P and remaining substantially against it. The plane P separates the end 12 of the conductor into two parts: an upper part 14, or section 14, which is above the plane P, and a lower part 15, which is below the plane P.

[0072] In Fig. 3B, the cutting blade 170 cuts the end 12 of the conductor into two parts, thus separating the section 14 from the lower part 15 of the conductor end. This cutting operation exposes a surface 16 which forms the upper surface of the part 15. The surface 16 is then an external surface of the end 12 of the conductor 10. As it is perfectly clean, the metal terminal can be formed directly on it.

[0073] Although removing a portion of the end of conductor 10 to expose the surface on which the terminal will be manufactured can be done before step S12, during which the end of the conductor is passed through the panel 115, it is preferable that step S12 be carried out before step S14, which removes the portion end (of section 14) of end 12 of the conductor.

[0074] Thus, step S10 is carried out in two steps: During step S12, the end 12 of the conductor 10 is passed through the retaining panel 115; and during step S14, a portion of the end of the conductor (section 14) is removed, so as to expose a surface of the conductor, which has become an external surface of the conductor: surface 16.

[0075] At the end of step S10, the surface 16 is at the bottom of the enclosure 110. The manufacturing nozzle 150 is then moved and positioned opposite the surface 16, to allow the manufacturing of the terminal 18.

[0076] The terminal 18 is then manufactured by additive manufacturing (operation S20), layer by layer. The first layer is formed directly on the surface 16: the deposited material (copper) is deposited directly onto this surface; no element is interposed between the deposited copper layer and the surface 16.

[0077] During the manufacturing operation of terminal 18 by additive manufacturing (operation S20), the end of the conductor (at this stage, section 15) is held in a fixed position by the retaining panel 115.

[0078] When terminal 18 is complete, manufacturing is stopped. The electrolytic bath 102 of sulfuric acid is emptied from the enclosure 140. During a step S30, the conductor 10 is extracted from the additive manufacturing machine 100. To free it from the retaining panel, the end 12 of the conductor, and in particular terminal 18, is brought out through the hole 112.

[0079] In other embodiments, other methods can be used to free the conductor 10 from the retaining panel 115. For example, the panel 115 can be formed in two parts, and the hole 112 is arranged between these two parts. The conductor 10 is then freed by separating the two parts of the panel 115 from each other.

[0080] Figure 5 represents an example of assembly 40 according to this disclosure.

[0081] Assembly 40 comprises the electrical conductor 10 and the terminal 18 attached thereto. The terminal 18 is attached to the conductor 10 by the process (or using the additive manufacturing machine) described in this disclosure. The end 12 of the conductor 10, after the terminal 18 has been manufactured, is formed by the section 15, to which the metal terminal 18 is attached (on its outer surface 16). In this embodiment, the terminal has substantially the same diameter D as the conductor 10, which allows it to be extracted through the hole 112. In other embodiments, the terminal may have a diameter larger than that of the hole (hole 112) through which the end of the conductor passed during manufacturing.

[0082] Figure 6 shows a connector 60 for connecting a multi-conductor electrical wire 50, according to this disclosure. Each of the conductors 10 of the wire 50 (This may only be the case for some of the conductors 10) is fixed to a metal terminal and thus, together with the terminal, forms an assembly 40 according to the present disclosure, identical or at least similar to the assembly 40 shown in [Fig. 5]. The connector 60 comprises a housing 62 inside which the assemblies 40 are fixed.

[0083] Although the present invention has been described with reference to a specific embodiment, it is evident that various modifications and changes can be made to this embodiment without departing from the general scope of the invention as defined by the claims. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

Claims

Demands

1. A method for manufacturing a metal terminal (18) at one end (12) of a single-strand or multi-strand electrical conductor (10), the method comprising the following operations: S10) positioning the end of the conductor in an enclosure (110) of an additive manufacturing machine (100); and S20) manufacturing the terminal (18) directly on an external surface (16) of the end of the electrical conductor by additive manufacturing; in which the operation S10 of positioning the end of the conductor comprises the following operations S12 and S14: S12) passing one end of the conductor having said external surface (16) through a retaining panel (115); and S14) removing a portion of the end of the conductor, so as to expose said external surface (16); the method being characterized in that operation S12 is carried out before operation S14.

2. A manufacturing method according to claim 1, wherein during the manufacturing operation S20, the end of the conductor is held in a fixed position by the retaining panel (115).

3. A manufacturing method according to claim 2, wherein the retaining panel (115) is part of a wall of the enclosure.

4. A manufacturing method according to any one of claims 1 to 3, wherein the manufacturing operation S20 of the end is carried out by electrolytic deposition.

5. A machine (100) for manufacturing a metal terminal (18) at the end of a single-strand or multi-strand electrical conductor (10); the machine (100) comprising a retaining panel (115); the machine comprising a manufacturing enclosure (110); the machine being configured to permit: S10) passing the end (12) of the electrical conductor (10) through a hole in the retaining panel (110) and holding an external surface (16) of the end of the electrical conductor in a fixed position within the manufacturing enclosure (110), using the retaining panel (115); and then S14) removing a portion of the end of the conductor, so as to expose said external surface using a cutting blade (170). of the machine; then S20) the end of the electrical conductor being thus held in a fixed position in the manufacturing enclosure (110), to manufacture the terminal (18) directly on said external surface (16) by additive manufacturing.