CN111390317A

CN111390317A - Double-sided tin dipping of coil, welding method thereof, coil and tap

Info

Publication number: CN111390317A
Application number: CN202010253768.5A
Authority: CN
Inventors: 唐叶飞; 吴文晶; 戴长喜; 王涛; 袁海峰; 周毅
Original assignee: Lanto Electronic Ltd
Current assignee: Lixun Precision Industry (Enshi) Co.,Ltd.
Priority date: 2020-04-02
Filing date: 2020-04-02
Publication date: 2020-07-10
Anticipated expiration: 2040-04-02
Also published as: CN111390317B

Abstract

The invention is suitable for the technical field of electronic component welding, and provides a coil double-sided tin dipping method, a coil welding method, a coil and a tap, wherein the coil tap double-sided tin dipping method comprises the following steps: A. irradiating the welding area of the coil by adopting first laser of a laser device to expose the conductive body of the welding area; B. dispensing solder paste on the conductive body exposed in the soldering region; C. hot-pressing the welding area, so that the solder paste positioned in the welding area is fixed on the surface of the conductive body, and a tin layer is formed on the conductive body; D. and cutting the conductive body of the welding area by adopting the second laser of the laser device in a fixed length manner. Therefore, the invention realizes the purpose of uniformly dipping tin on both sides of the coil.

Description

Double-sided tin dipping of coil, welding method thereof, coil and tap

Technical Field

The invention relates to the technical field of electronic component welding, in particular to a coil with double-sided tin dipping and a welding method thereof, a coil and a tap.

Background

Referring to fig. 1 and 2, the product is shown as a customer requiring double-sided tin-dipping of the product for a coil, and the dimension thickness after tin-dipping is controlled to +/-0.025, and the conventional tin-plating method is as follows: 1. direct tin furnace tin dipping, but it is difficult to control the size and appearance, in fig. 1, the copper conductor 11, the tin dots 12, the thick tin 13 and the thin tin 14 are seen, because there are tin dots 12 and the tin is not uniformly coated, the tin is too much and 100% NG thick, and the appearance is NG. In fig. 2, copper conductor 11, thick tin 22, thin tin 23, where the conductor is melted, width NG, and the amount of tin is not sufficient. Tin wires are adopted and then HB operation is carried out, so that tin overflow and tin shortage are easy, and tin is difficult to be adhered to the back surface.

In the prior art, the application numbers are: 201410079255.0, the invention name is magnetic coil welding method, discloses a magnetic coil welding method, includes the following steps: providing an insulating base, wherein the insulating base comprises a plurality of side walls and a bottom wall, the side walls and the bottom wall form an accommodating groove, the side walls of the insulating base are provided with a plurality of mutually separated soldering tin grooves, the insulating base also comprises a plurality of conductive terminals fixed on the side walls, and the conductive terminals are provided with welding planes exposed in the soldering tin grooves; providing a bracket with at least one fixing groove, and fixing the insulating base on the fixing groove; providing a magnetic coil with a plurality of leads, wherein the magnetic coil is accommodated in the accommodating groove; put the lead wire in the soldering tin groove, make the lead wire be located the plane of welding top, still include following steps: welding the lead and the welding plane into a whole through a welding head; removing the insulating layer on the surface of the lead of the soldering tin groove; solder is added into the soldering tin groove and is fixed on the soldering plane by heating. However, this solution does not provide a good solution for double-sided tin dipping and removing the overflowing tin.

In view of the above, it is obvious that the prior art has inconvenience and disadvantages in practical use, so that improvement is needed.

Disclosure of Invention

In view of the above-mentioned drawbacks, the present invention provides a coil with double-sided tin dipping, a method for soldering the coil, a coil and a tap, so as to achieve double-sided uniform tin dipping of the coil.

In order to achieve the above object, the present invention provides a method for double-sided tin dipping of a coil, the coil includes at least a conductive body and an insulating outer film, the insulating outer film is wrapped outside the conductive body, the coil has at least a soldering region, the method includes:

A. irradiating the welding area of the coil by adopting first laser of a laser device to expose the conductive body of the welding area;

B. dispensing solder paste on the conductive body exposed in the soldering region;

C. hot-pressing the welding area, so that the solder paste positioned in the welding area is fixed on the surface of the conductive body, and a tin layer is formed on the conductive body;

D. and cutting the conductive body of the welding area by adopting the second laser of the laser device in a fixed length manner.

According to the method, in the step B, the solder paste is further dotted on the conductive body in a dotted manner.

According to the method, in the step C, pressure welding is simultaneously performed from the upper surface and the lower surface of the conductive body by a hot pressure welding apparatus.

According to the method, the step D comprises the following steps:

d1, shooting the conductive body with a tin layer by using an imaging device;

d2, moving the coil into a preset wire frame, and cutting the coil according to the wire frame by using the second laser.

According to the method, the coil is a multi-strand copper wire and the soldering region is a tap of the coil around a planar coil.

According to the method, the multi-strand copper wire parallel winding planar coil is a wireless charger coil of the mobile terminal; the tap of the coil is flat.

In order to achieve another object of the invention, the invention provides a method for soldering a coil, wherein the coil is subjected to double-sided tin dipping by any one method and then is soldered to a PAD of a PCB (printed circuit board) by means of hot-press soldering.

According to the soldering method, the double-sided tin dipping is carried out, so that the variation range of the size thickness after tin is controlled within +/-0.025 mm.

In order to achieve another object of the invention, the invention also provides a coil produced by using the double-sided tin dipping method of any one coil.

The invention also provides a coil with any one of the coil taps.

According to the invention, the coil is irradiated by the first laser of a laser device, so that the insulating paint on the coil is vaporized and leaks out of the conductive body; applying solder paste to the conductive body; uniformly plating tin on the surface of the conductive body by adopting a hot-pressing and hot-melting tin welding hot-pressing mode; and cutting the tap plated with tin at fixed length by adopting a second laser of the laser device. Therefore, double-sided uniform tin dipping of the coil is realized, and especially double-sided uniform tin dipping of a plurality of strands of copper wires and a coil flat tap is realized.

Drawings

FIG. 1 is a schematic diagram of a tapped double-sided uneven tin pick-up of a coil in the prior art;

FIG. 2 is a schematic diagram of a tapped double-sided uneven tin pick-up of a coil in the prior art;

FIG. 3 is a flow chart of a method for double-sided tin dipping of a tap of a coil according to an embodiment of the present invention;

FIG. 4 is a schematic illustration of a coil provided in accordance with an embodiment of the present invention after vaporization of the tap insulation varnish;

FIG. 5 is a schematic view of a tap provided by an embodiment of the present invention for applying solder paste to a coil after evaporation of an insulating varnish;

FIG. 6 is a schematic diagram of a tapped double-sided uniform tin dipping of a coil according to an embodiment of the present invention;

fig. 7 is a schematic diagram of a tapped coil with tin overflow according to an embodiment of the present invention.

Wherein:

11-conductive body 12-tin spot 13-thick tin 14-thin tin

22-thick tin 23-thin tin 41-conductive body 42-insulating varnish

52-solder paste 62-tin 72-tin plated area 400-coil

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be appreciated that references in the specification to "one embodiment," "an example embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not intended to refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

Where certain terms are used in the specification and following claims to refer to particular components or features, those skilled in the art will understand that various terms or numbers may be used by a skilled user or manufacturer to refer to the same component or feature. This specification and the claims that follow do not intend to distinguish between components or features that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. In addition, the term "connected" is intended to encompass any direct or indirect electrical connection. Indirect electrical connection means include connection by other means.

It should be noted that in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

Referring to fig. 3 to 7, in an embodiment of the present invention, a method for double-sided tin dipping of a coil 400 is provided, the coil 400 includes at least one conductive body 41 and an insulating outer film, the insulating outer film is wrapped outside the conductive body 41, the coil 400 has at least one soldering region, the method includes:

s301, irradiating a welding area of the coil 400 by using first laser of a laser device to expose the conductive body 41 in the welding area;

in this step, an operator may set a predetermined welding area for the coil on the machine, the welding area may also be a tap of the coil 400, and the laser device irradiates a first laser to the welding area, and vaporizes an insulating coating of the welding area through the first laser, so as to expose a conductive core wire of the welding area. The coil 400 is formed by arranging a plurality of bare wires in parallel, wherein each bare wire has a conductive core wire and an insulating outer covering, which is externally arranged on the core wire, wherein the insulating outer covering can be insulating varnish or insulating rubber. In another embodiment, the coil 400 may also be formed by arranging a plurality of conductive cores in parallel, and providing an insulating coating on the outer layer of the plurality of conductive cores. The conductive body 41 is one or more conductive core wires, and in the embodiment of the present invention, the conductive body 41 is a copper conductor, but not limited thereto, and may also be a conductive body 41 made of other materials, such as aluminum.

S302, dispensing solder paste on the conductive body 41 exposed in the welding area;

in this step, solder paste is applied to the conductive body 41 of the soldering region described in step S301. The solder paste may be applied by manual or mechanical dispensing, and referring to fig. 5, the solder paste 52 is dispensed onto the conductive body 41.

S303, hot-pressing the soldering region, so that the solder paste in the soldering region is fixed on the surface of the conductive body 41, and a solder layer is formed on the conductive body 41;

in this step, Hot pressing process of Hot-bar can be adopted, the solder paste changes its fluidity at high temperature, and through the pressing action of Hot-bar, the solder paste at high temperature can be uniformly plated on the conductive body 41 in the soldering region. The solder paste 52 has better fluidity at high temperature and can flow to the lower surface of the flat conductive body 41 through the fine gaps.

S304, cutting the conductive body 41 of the welding area by a fixed length by adopting the second laser of the laser device

In this step, after Hot-bar is away from the soldering region, the temperature of the soldering region is lowered to room temperature, and the solder paste applied to the conductive body 41 of the soldering region is solidified into a solder bump. If the size and the position of the tin block do not meet the size requirement of pre-tinning, a laser device is adopted to irradiate the second laser on the tin block in the welding area, so that the redundant tin block is separated from the coil.

In an embodiment of the present invention, the step S304 includes:

d1, shooting the conductive body 41 with an imaging device;

d2, moving the coil 400 into a preset wire frame, and cutting the coil 400 according to the wire frame by using the second laser.

In this embodiment, the size of the tin-plated area 72 is precisely controlled by a second laser cut-to-length cut by the laser device, see FIG. 7, where the coil 400 (L ead) has a pre-tin-plated area length of 2+/-0.15mm, and the laser depainting range increases to 4+/-0.1mm during the manufacturing process, see FIG. 4, where the coil 400 (L ead) has a preliminary tin-plated area range of 4+/-0.5mm, see FIG. 6, where the pre-tin-plating size requirement is clearly not met, and where the excess area is cut off to 2+/-0.15mm by a visually positioned laser, see FIG. 7.

In an embodiment of the invention, in the step S302, the solder paste is further applied to the conductive body 41 by dot coating.

In one embodiment of the present invention, referring to fig. 5, in the step S303, pressure welding is simultaneously performed from the upper surface and the lower surface of the conductive body 41 by a hot pressure welding apparatus. And uniformly plating tin on the conductive body 41 by adopting a Hot-pressing mode of Hot-bar.

Preferably, the coil 400 is a multi-strand copper wire and a parallel wound planar coil; the welding area is a tap of the coil 400, and the tap of the coil 400 is flat. The coil 400 is flat. The multi-strand copper wire parallel winding planar coil is a wireless charger coil of the mobile terminal.

In one embodiment of the invention, the project requires that the thickness of the pre-tinning area of the coil 400 (L ead) is 0.147+/-0.025mm, the thickness of the wire per se is 0.140mm, the thickness of the single-sided tinning of L ead cannot exceed 0.015mm, the single-sided tinning by adopting a tin dipping or spraying mode at least reaches 0.05mm and has unstable dimension, obviously, the product dimension requirement cannot be met, and the (HB) hot-press welding is controlled by a servo motor mode, and the pressing height precision can reach 0.01 mm.

In one embodiment of the present invention,

the first step is as follows: a plurality of strands of copper wires are vaporized by laser (1) around the insulating varnish 42 on the flat taps of the coil, so that the copper wires leak out of the conductive body 41, see fig. 4;

the second step is that: spot-coating solder paste 52 onto the upper surface of side-by-side conductive body 41, see fig. 5;

the third step: tin 62 is uniformly plated on the conductive body 41 by Hot pressing at Hot bar (tin paste with good fluidity can flow to the lower surface of the flat conductive body 41 through a fine gap) as shown in fig. 6;

the fourth step: the laser (2) cuts to length, and the size of the tin-plating area 72 can be accurately controlled, see fig. 7. The tin plating area 72 is less than or equal to the size of the soldering area minus the coated conductive body 42.

In the embodiment, the manufacturing process adopts the traditional laser and HB (Hot-bar lead, Hot-press welding coil flat tap tin pre-coating) tin pre-coating operation process, and the requirements of product size and double-side tin coating are met through the combination of the laser and the HB. Firstly, paint is removed by adopting first laser of a laser device, then tin paste HB is spotted for operation, the thickness of a product is ensured, then laser cutting is carried out, and the length and the size of the product after tin soldering are ensured.

In one embodiment of the present invention, the coil 400 is soldered to a PAD (PAD) of a PCB after being double-sided tinned by any of the above-described methods by means of thermocompression bonding. Specifically, the subsequent process of double-sided soldering, such as soldering on a circuit board, is completed at the system assembling end, that is, a plurality of strands of copper wires which are pre-soldered and are wound around a coil flat tap are soldered on the PAD of the PCB by means of thermocompression soldering. Wherein the double-sided tin dipping is carried out so that the variation range of the size and the thickness after tin is controlled within +/-0.025 mm.

In one embodiment of the present invention, there is provided a coil 400 produced by any of the above methods of double-sided wicking of a coil. And a coil 400, the coil 400 having a coil tap as described in any of the previous embodiments.

In summary, the coil is irradiated by the first laser of the laser device, so that the insulating varnish on the coil is vaporized and leaks out of the conductive body; applying solder paste to the conductive body; uniformly plating tin on the surface of the conductive body by adopting a hot-pressing and hot-melting tin welding hot-pressing mode; and cutting the tap plated with tin at fixed length by adopting a second laser of the laser device. Therefore, double-sided uniform tin dipping of the coil is realized, and especially double-sided uniform tin dipping of a plurality of strands of copper wires and a coil flat tap is realized.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it should be understood that various changes and modifications can be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for double-sided tin dipping of a coil, the coil comprising at least one conductive body and an insulating outer film, the insulating outer film being wrapped outside the conductive body, the coil having at least one soldering region, the method comprising:

2. The method of claim 1, wherein in step B, the solder paste is further applied by spot coating onto the conductive body.

3. The method according to claim 1, wherein in the step C, pressure welding is simultaneously performed from the upper surface and the lower surface of the conductive body by a hot pressure welding apparatus.

4. The method of claim 1, wherein step D comprises:

d1, shooting the conductive body with a tin layer by using an imaging device;

5. The method of claim 1 wherein the coil is a multi-strand copper wire and the weld region is a tap of the coil around a planar coil.

6. The method of claim 5, wherein the multi-strand copper wire and parallel wound planar coil is a wireless charger coil of a mobile terminal; the tap of the coil is flat.

7. A method for soldering a coil, characterized in that the coil is soldered to a PAD of a PCB by means of hot-press soldering after double-sided tinning of the coil by the method of any of claims 1 to 6.

8. The method of soldering of claim 7 wherein said double-sided tin dipping is performed such that the post-tin dimensional thickness variation range is controlled to +/-0.025 mm.

9. A coil formed by the double-sided tinning method of the coil according to any one of claims 1 to 6.

10. A coil with a coil tap according to any one of claims 9.