CN117226210A

CN117226210A - Welding method for high-density pins

Info

Publication number: CN117226210A
Application number: CN202311237986.XA
Authority: CN
Inventors: 王宏信; 潘广
Original assignee: Hunan Vathin Medical Instrument Co Ltd
Current assignee: Hunan Vathin Medical Instrument Co Ltd
Priority date: 2023-09-25
Filing date: 2023-09-25
Publication date: 2023-12-15

Abstract

The application discloses a welding method of high-density pins, and relates to the technical field of assembly and manufacturing in the electronic industry. The welding method of the high-density pins comprises the following steps: dipping one end of a wire to be welded with soldering flux, and adhering the soldering flux to the wire to be welded by using the soldering flux; heating the solder to enable the solder to be in a molten state, vertically placing a wire to be welded, and enabling the molten solder to form an ellipsoidal solder ball at the end part of the wire to be welded; and (3) approaching the lead to be welded to the pin to be welded, heating the ellipsoidal solder ball to melt the ellipsoidal solder ball, and welding the lead to be welded with the pin to be welded by utilizing the melted ellipsoidal solder ball. The welding method of the high-density pins is easy to realize accurate welding of the wires to be welded and the pins to be welded, and is simple to operate, feasible and efficient.

Description

Welding method for high-density pins

Technical Field

The application relates to the technical field of assembly and manufacturing in the electronic industry, in particular to a welding method of high-density pins.

Background

In debugging or maintenance of hardware devices such as a circuit board, a chip pin is required to be connected with a detection device or other welding spots through a wire, and in general, the wire is fixedly connected with the chip pin through a welding mode.

However, the inventors found that: when the pitch of the pins is smaller (also called as high-density pins) or the pins are only a small part of the exposed chips, the welding operation between the wires and the pins is more difficult. Specifically, for high-density pins, the interval between the pins is very small, and in the prior art, the method of soldering the solder on the electric soldering iron is directly used, so that adjacent pins or more pins are easily connected with the solder tin, and the problem of short circuit is caused; the solder tin causing short circuit is cleaned and welded in the follow-up welding; even multiple iterations are required to succeed. The denser the pins are, the more the difficulty is multiplied, and the success rate is obviously reduced.

Therefore, providing a welding method suitable for high-density pins to improve the welding success rate is a technical problem to be solved by those skilled in the art.

Disclosure of Invention

The application discloses a welding method of high-density pins, which aims to solve the technical problems that the operation difficulty is high and the high-density pins are required to be repeatedly welded in the prior art.

In order to solve the problems, the application adopts the following technical scheme:

the welding method of the high-density pins comprises the following steps:

step S100: dipping one end of a wire to be welded with soldering flux, and adhering the soldering flux to the wire to be welded by using the soldering flux;

step S200: heating the solder to enable the solder to be in a molten state, vertically placing a wire to be welded, and enabling the molten solder to form an ellipsoidal solder ball at the end part of the wire to be welded;

step S300: and (3) approaching the lead to be welded to the pin to be welded, heating the ellipsoidal solder ball to melt the ellipsoidal solder ball, and welding the lead to be welded with the pin to be welded by utilizing the melted ellipsoidal solder ball.

According to a preferred embodiment, before step S100, a step of preparing solder is further included, and the preparing solder includes the steps of:

thinning and shortening the solder based on the density of the pins to be welded, and enabling the thickness and the length of the solder after the treatment to be smaller than or equal to the interval between the pins to be welded and the adjacent pins; and/or

Thinning and shortening the solder based on the length of the exposed part of the pin to be welded, and enabling the thickness and the length of the solder after the treatment to be smaller than or equal to the length of the exposed part of the pin to be welded; and/or

And thinning and shortening the solder based on the diameter of the pin to be welded, and enabling the thickness and the length of the solder after the treatment to be smaller than or equal to the diameter of the pin to be welded.

According to a preferred embodiment, before the wire to be soldered approaches the pin to be soldered, the method further comprises the steps of cooling the ellipsoidal solder ball for 1-3 seconds and solidifying the ellipsoidal solder ball.

According to a preferred embodiment, in step S100, the soldering flux is a paste; the weight ratio of the soldering flux to the solder is 1:1-1:2.

According to a preferred embodiment, in step S200, the following steps are further included: after the wire to be welded is vertically placed, observing whether the molten solder is positioned at the end part of the wire to be welded, and cutting off and/or supplementing redundant parts of the end part of the wire to be welded when the molten solder lower end part is positioned above the end part of the wire to be welded and the distance between the molten solder lower end part and the end part of the wire to be welded exceeds a preset length.

According to a preferred embodiment, the formulation used for the feed comprises a flux and a solder, and the weight ratio of flux to solder is 1:1 to 1:2.

According to a preferred embodiment, in step S200, the solder is intermittently supplied with heat by using a hot air source, the solder is melted under the action of the heat, and the hot air source is kept to operate at a minimum wind speed, and the included angle between the wind outlet direction of the hot air source and the wire to be soldered is 30-60 °.

According to a preferred embodiment, in step S300, when the wire to be soldered is close to the pin to be soldered, the wire to be soldered is located above the pin to be soldered, or the wire to be soldered is located on the side surface of the pin to be soldered, and the vertical distance between the end of the wire to be soldered and the pin to be soldered is 3-5 mm, and the wire to be soldered and the pin to be soldered remain parallel, or the included angle between the wire to be soldered and the pin to be soldered is smaller than 10 °.

According to a preferred embodiment, in step S300, the ellipsoidal solder balls are intermittently or continuously heated by using a hot air source based on at least one of the molten state of the ellipsoidal solder balls, the molten state of the pins to be soldered, the wind speed of the hot air gun, and the wind speed of the soldering station, and the ellipsoidal solder balls are remelted by the heat.

According to a preferred embodiment, the angle between the air outlet direction of the hot air source and the wire to be soldered is 30-90 °.

The welding method of the high-density pins provided by the application at least has the following beneficial effects:

compared with the welding mode of using an electric soldering iron in the prior art, the method for welding the high-density pins comprises the steps of dipping the solder on the wires to be welded, melting and shaping the solder, and melting and welding the solder again. Therefore, compared with the method for welding by using an electric soldering iron in the prior art, the method for welding the high-density pins is easy to realize accurate welding of the wire to be welded and the pins to be welded, is simple to operate, easy to implement and high in efficiency, and solves the technical problems that the operation difficulty is high and repeated times are needed to be successful when the high-density pins are welded in the related art.

In the second aspect, after the solder is heated to make the solder be in a molten state, the wire to be soldered is vertically placed, so that the soldering flux and the solder can move towards the end of the wire to be soldered under the action of gravity. The solder balls with the slender ellipsoidal structures can enable the diameters of the solder balls to be smaller, namely the widths occupied by the solder balls are smaller, and when the lead to be soldered is close to the pin to be soldered, the problem of short circuit caused by the connection of the solder and the pin to be soldered can be further avoided; meanwhile, if the solder ball is located on the side surface of the pin to be welded, after the solder ball is melted again, the solder ball and the pin to be welded have larger contact area, so that as much solder as possible contacts with the pin to be welded, and the welding reliability between the wire to be welded and the pin to be welded is improved.

In the third aspect, the precision of the electric soldering iron is higher at present, but the soldering method of the high-density pin directly uses the wire to be soldered to pick up the soldering flux and the solder. Therefore, the welding method of the high-density pins can be realized by only using conventional hot air source equipment, the precision of the required equipment is not required, compared with the welding operation in the prior art which needs to use high-precision electric soldering iron, the required equipment is definitely easier to obtain and lower in cost, on the other hand, the wire with smaller diameter and/or spacing than the pins to be welded is selected, and compared with the electric soldering iron with smaller end size than the pins to be welded, the welding method of the high-density pins is easier to realize.

Drawings

In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a first flow chart of a method for soldering high density pins according to an embodiment of the present application;

FIG. 2 is a second flowchart of a method of soldering high density pins according to an embodiment of the present application;

FIG. 3 is a third flow chart of a method of soldering high density pins according to an embodiment of the present application;

FIG. 4 is a schematic diagram of a first structure of an ellipsoidal solder ball formed at the end of a wire to be soldered according to an embodiment of the present application;

FIG. 5 is a schematic diagram of a second structure of an ellipsoidal solder ball formed at the end of a wire to be soldered according to an embodiment of the present application;

FIG. 6 is a schematic illustration of the wire to be soldered of FIG. 5 after cutting off the excess wire;

fig. 7 is a schematic structural diagram of a wire to be soldered after approaching a first type of pin to be soldered;

fig. 8 is a schematic diagram of the structure of the wire to be soldered after approaching the second type of pin to be soldered.

In the figure: 101. a wire to be welded; 1011. the end part of the wire to be welded; 102. ellipsoidal solder balls; 201. pins; 2011. a side pin; 2012. a front pin; 201a, a pin tilting part; 201b, pin horizontal part; 202. a chip body; 301. and an air outlet.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail below. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. All other embodiments, based on the examples herein, which are within the scope of the application as defined by the claims, will be within the scope of the application as defined by the claims.

The terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged, as appropriate, such that embodiments of the present application may be implemented in sequences other than those illustrated or described herein, and that the objects identified by "first," "second," etc. are generally of a type, and are not limited to the number of objects, such as the first object may be one or more. Furthermore, in the description and claims, "and/or" means at least one of the connected objects, and the character "/", generally means that the associated object is an "or" relationship.

In the related art, when the pin space is smaller, if a conventional electric iron is used for welding between the lead and the pin, the electric iron is close to the pin to be welded due to the larger size, and the end part of the electric iron has the problem of occupying space across the pin, so that the solder is easy to connect with the adjacent pin or more pins, the problem of short circuit is caused, the welding can be performed only after the solder causing the short circuit is cleaned, and the welding difficulty is high and the efficiency is low; on the other hand, even if the high-precision electric iron is used for welding, the problem of short circuit is unavoidable, and the high-precision electric iron is high in cost and not easy to obtain, and is not available under all working conditions.

Therefore, the application provides a welding method of high-density pins, which is characterized in that soldering flux and welding flux are directly adhered to wires to be welded, then the soldering flux and the welding flux are melted and shaped, and finally the wires to be welded are close to the pins to be welded, and the soldering flux and the welding flux are melted again, so that the wires to be welded and the pins to be welded can be welded. The method is easy to realize accurate welding of the wire to be welded and the pin to be welded, is simple to operate, easy to implement and efficient, and has no requirement on the precision of required equipment.

The following describes in detail the method for welding the high-density pins according to the embodiment of the present application through specific embodiments and application scenarios thereof with reference to fig. 1 to 8.

The high-density leads in this embodiment are the chip leads of the package such as LQFP (quad flat package technology, package body thickness of 1.4 mm), QFP (Fang Bianping package technology), TSSOP (thin, small-size package), etc., and the lead portions are exposed.

Fig. 1 shows a flow chart of a method of soldering high density pins. As shown in fig. 1, the welding method of the high-density pins comprises the following steps:

step S100: one end of the wire 101 to be soldered is dipped with a flux, and the flux is used to adhere the solder to the wire 101 to be soldered. Wherein, the diameter of the wire 101 to be soldered is smaller than the diameter of the pin to be soldered, and/or the diameter of the wire 101 to be soldered is smaller than the interval between the pin to be soldered and the adjacent pin.

Specifically, the wire 101 to be soldered may use a copper wire or a tin-plated copper wire or the like, and particularly a bare wire of a copper wire or a tin-plated copper wire or the like. If there is a lacquer coating outside the copper wire or tin-plated copper wire, the lacquer film at the welded end needs to be removed at least first. The diameter of the bare wire of the copper wire or tin-plated copper wire should also be smaller than the diameter of the pin to be soldered (herein, the diameter of the pin to be soldered when the pin to be soldered is a columnar structure; the width of the pin to be soldered when the pin to be soldered is a plate-like structure), and/or the diameter of the wire to be soldered 101 is smaller than the pitch between the pin to be soldered and the adjacent pin.

At present, the precision of the electric soldering iron is higher, but the soldering method of the high-density pin in this embodiment directly uses the wire 101 to be soldered to pick up the soldering flux and the solder. Therefore, the welding method of the high-density pins in the embodiment can be realized by only using conventional hot air source equipment, and has no requirement on the precision of the required equipment, and compared with the welding operation in the prior art which needs to use high-precision electric soldering iron, the required equipment in the embodiment is definitely easier to obtain and has lower cost, on the other hand, the welding method of the high-density pins in the embodiment has the advantage of easy realization by selecting the wires with smaller diameters and/or pitches than the pins to be welded and compared with the electric soldering iron with smaller end sizes than the pins to be welded.

The soldering flux is dipped at one end of the wire 101 to be soldered, and the soldering quality and the soldering efficiency between the wire 101 to be soldered and the pin to be soldered can be improved by the action of the soldering flux. Specifically, in the first aspect, the soldering flux can remove impurities such as oxides, grease, dust and the like on the welding surface, keep a welding area clean and is beneficial to the formation of welding seams; in the second aspect, during the welding process, the soldering flux can react with oxygen in the air to form an oxide protection layer to prevent the welding area from being oxidized again, so that the oxide content in the welding seam is reduced; in the third aspect, the components in the soldering flux can reduce the melting point of the solder, so that the solder is easier to melt and flow, the wettability of the welding seam is improved, the bonding between welding metals is facilitated, the heat required for melting the solder can be saved, and the purpose of energy conservation is achieved; in a fourth aspect, the components in the flux are capable of absorbing and exhausting moisture and other volatile materials in the weld area, reducing gas accumulation in the weld, thereby reducing the risk of cold cracking and blowholes; in the fifth aspect, the use of the flux can improve the shape of the weld, increase the welding strength and the sealing property, reduce the occurrence probability of welding defects, and improve the welding quality and the reliability of welding connection. Namely: the soldering flux can play various roles of cleaning the surface, preventing oxidization, wetting, removing impurities, eliminating air holes and the like in the welding process, and is beneficial to realizing high-quality welding connection.

Preferably, the soldering flux of the present application is a paste. More preferably, the flux is a solder paste, stainless steel solder, braze paste, or aluminum solder paste. The paste soldering flux not only has the functions of the soldering flux, but also has certain viscosity, so that the soldering flux can be conveniently adhered to the wire 101 to be soldered, and the soldering flux can be conveniently adhered to the wire 101 to be soldered; meanwhile, the flux consumption is convenient to control, so that the welding operation is more convenient and accurate.

Preferably, the weight ratio of the soldering flux to the solder is 1:1-1:2. More preferably, the solder is tin. The scaling powder also has the effect of reducing the surface tension of the tin material, and the proportion of the scaling powder is too small, so that the effect of reducing the surface tension of the tin material is weakened, and the flow of the solder to the end 1011 of the wire to be welded is not facilitated; because the flux has a lower melting point than solder, an excessive proportion of flux will cause the flux that was melted first to coat the solder, thereby compromising the melting of the solder and the formation of the ellipsoidal solder balls 102.

Step S200: the solder is heated to make the solder in a molten state, the wire 101 to be soldered is vertically placed, and the molten solder forms an ellipsoidal solder ball 102 at the end of the wire 101 to be soldered. A schematic diagram of the molten solder forming an ellipsoidal solder ball 102 at the end of a wire 101 to be soldered is shown in fig. 4.

Specifically, the solder can be heated by conventional devices such as a hot air source and the like capable of providing a hot air source, the solder can be melted by heating the solder to a temperature above 232 ℃, after the solder is melted, the wire 101 to be soldered is vertically placed, the soldering flux and the solder can move towards the end of the wire 101 to be soldered under the action of gravity, and as the mixture formed by the soldering flux and the solder has a certain viscosity, when the soldering flux and the solder move towards the end of the wire 101 to be soldered under the action of gravity, part of the soldering flux and the solder adhere to the wire, and part of the soldering flux and the solder flow downwards, so that the solder ball formed at the end of the wire 101 to be soldered is of an elongated ellipsoidal structure. The hot air source is, for example, a hot air gun or a welding table.

The solder balls with the slender ellipsoidal structures can enable the diameters of the solder balls to be smaller, namely the widths occupied by the solder balls are smaller, and when the lead 101 to be soldered is close to the pin to be soldered, the problem of short circuit caused by the connection of the solder and the pin to be soldered can be further avoided; meanwhile, if the solder ball is located at the side of the pin to be soldered, after the solder ball is melted again, the solder ball and the pin to be soldered have larger contact area, so that as much solder as possible contacts the pin to be soldered, and the reliability of soldering between the wire 101 to be soldered and the pin to be soldered is improved.

Step S300: the wire 101 to be soldered is brought close to the pin to be soldered, the ellipsoidal solder ball 102 is heated to melt the ellipsoidal solder ball, and the wire 101 to be soldered is soldered to the pin to be soldered by using the melted ellipsoidal solder ball 102.

Specifically, since the diameter of the wire 101 to be soldered is smaller than the diameter of the pin to be soldered, and/or the diameter of the wire 101 to be soldered is smaller than the distance between the pin to be soldered and the adjacent pin, when the wire 101 to be soldered is close to the pin to be soldered, the wire 101 to be soldered does not occupy the positions of the other pins, so that the problem of short circuit caused by connection of solder and the pin to be soldered is not easy to occur.

Similarly, the ellipsoidal solder balls 102 can be heated by conventional devices such as a hot air source and the like capable of providing a hot air source, the ellipsoidal solder balls 102 can be melted again by heating the ellipsoidal solder balls 102 to more than 232 ℃, after the ellipsoidal solder balls 102 are melted again, the melted solder is contacted with the pins to be soldered, then the hot air source is moved away, and the wires 101 to be soldered and the pins to be soldered can be soldered after the solder is cooled.

Compared with the prior art in which an electric soldering iron is used for soldering, the method for soldering the high-density pins comprises the steps of dipping the lead 101 to be soldered, melting and shaping the solder, and melting and soldering the solder again. Therefore, compared with the method for welding by using an electric soldering iron in the prior art, the welding method for the high-density pins of the embodiment is easy to realize accurate welding of the wire 101 to be welded and the pins to be welded, is simple, feasible and efficient in operation, and solves the technical problems that the operation difficulty is high and the wire 101 to be welded needs to be repeated for many times to be successful when the high-density pins are welded in the related art.

Fig. 2 shows another flow chart of a method of soldering high density pins. As shown in fig. 2, before step S100, a step of preparing solder is further included. Specifically, the preparation of the solder comprises the following steps:

and thinning and shortening the solder based on the density of the pins to be welded, and enabling the thickness and the length of the solder after the treatment to be smaller than or equal to the interval between the pins to be welded and the adjacent pins. And/or thinning and shortening the solder based on the length of the exposed part of the pin to be soldered, and enabling the thickness and the length of the solder after the treatment to be smaller than or equal to the length of the exposed part of the pin to be soldered. And/or thinning and shortening the solder based on the diameter of the pin to be soldered, and enabling the thickness and length of the solder after the treatment to be smaller than or equal to the diameter of the pin to be soldered.

Specifically, the solder is a tin wire, and the tin wire is thinned and shortened, that is, the dimension in the thickness direction and the dimension in the length direction of the tin wire are reduced. Specifically, the treatment can be performed by using tools such as a vice. The denser the pins of the chip to be welded are, the thinner the treated tin wires are, and the shorter the tin wire size is; the shorter the length of the exposed part of the pin to be welded is, the thinner the treated tin wire is, and the shorter the tin wire size is; the smaller the diameter (or width) of the pin to be soldered, the thinner the treated tin wire, and the shorter the tin wire size. According to the welding method of the preferred technical scheme of the embodiment, the welding flux is thinned and shortened so as to control the consumption of the welding flux, and the problem that the welding flux overflows to adjacent pins after being melted to cause short circuit is avoided.

The solder material may be, but not limited to, solder balls as they are.

Fig. 3 shows a third flowchart of a method of soldering high density pins. As shown in fig. 3, before the wire 101 to be soldered approaches the pin to be soldered, the method further includes a step of cooling the ellipsoidal solder ball 102 for 1-3 seconds and solidifying the ellipsoidal solder ball 102. Specifically, the hot air source is turned off, so that the hot air source provides hot air for the wire 101 to be soldered, and the melted ellipsoidal solder balls 102 are naturally cooled for 1-3 seconds to solidify. According to the welding method of the preferred technical scheme of the embodiment, before the lead 101 to be welded approaches to the pin to be welded, the ellipsoidal solder balls 102 are solidified in a cooling mode, so that the ellipsoidal solder balls 102 can always maintain an ellipsoidal state in the process of approaching the lead 101 to be welded to the pin to be welded, and the change of the morphology of the ellipsoidal solder balls 102 in the moving process is avoided; meanwhile, the solidification can also enhance the connection strength between the ellipsoidal solder balls 102 and the wires 101 to be soldered, so that the ellipsoidal solder balls 102 can be always positioned at the lower end parts of the wires 101 to be soldered, and the problem that the ellipsoidal solder balls 102 drop in the moving process is avoided.

According to a preferred embodiment, in step S200, the following steps are further included: after the wire 101 to be welded is vertically placed, observing whether molten solder is located at the end of the wire 101 to be welded, and cutting off and/or supplementing redundant parts of the end of the wire 101 to be welded when the molten solder is located above the end of the wire 101 to be welded and the distance between the molten solder and the end of the wire 101 to be welded exceeds a preset length. Specifically, the preset length is, for example, 0.1 to 1mm. When the distance between the molten solder and the end of the wire 101 to be soldered exceeds a preset length, the redundant wire 101 to be soldered can be directly sheared off along the lower end face of the solder through a vice; or re-dipping the flux and the solder, so that an ellipsoidal solder ball 102 is formed at the end of the wire 101 to be soldered. During the process of cutting off the redundant wires, the problem of solder loss may exist, and the soldering flux and the solder can be newly dipped at the moment to perform the feeding operation. Fig. 5 shows a schematic view of the lower end of the solder in a molten state being higher than the end of the wire 101 to be soldered, that is, there is an excess portion under the wire 101 to be soldered; fig. 6 shows a schematic view of cutting off the excess portion under the wire 101 to be soldered.

When the soldering flux and the solder move to the end of the wire 101 to be soldered under the action of gravity, the flow of the soldering flux and the solder is possibly blocked due to the influence of factors such as unsmooth wall surface of the wire, so that the end of the wire 101 to be soldered is not provided with the solder or only provided with a small amount of solder, the reliability of the connection between the subsequent wire 101 to be soldered and the pin to be soldered is affected, and when the wire 101 to be soldered approaches to the pin to be soldered, the problem that the wire 101 to be soldered stretches across the pin to occupy space can occur, and the solder is easy to be connected with adjacent pins or more pins, so that the problem of short circuit is caused; and is also unfavorable for realizing the accurate butt joint of the wire 101 to be welded and the pin to be welded. According to the welding method of the preferred technical scheme of the embodiment, redundant parts of the end part of the wire 101 to be welded are sheared and/or fed, so that the ellipsoidal solder balls 102 can be ensured to be positioned at the end part of the wire 101 to be welded, and the end part 1011 of the wire to be welded can be ensured to have enough solder, thereby having the advantages of enhancing the connection reliability of the wire 101 to be welded and the pin to be welded, avoiding the connection of the solder and the adjacent pin, and being beneficial to the accurate butt joint of the wire 101 to be welded and the pin to be welded.

Preferably, the formula used for the feed comprises soldering flux and solder, and the weight ratio of the soldering flux to the solder is 1:1-1:2. The soldering flux and the solder which are dipped in the initial state have the effect of reducing the surface tension of the solder, the proportion of the soldering flux is too small, the effect of reducing the surface tension of the solder is weakened, and the solder is not beneficial to flowing to the end 1011 of the lead to be soldered; because the flux has a lower melting point than solder, an excessive proportion of flux will cause the flux that was melted first to coat the solder, thereby compromising the melting of the solder and the formation of the ellipsoidal solder balls 102.

According to a preferred embodiment, in step S200, the solder is intermittently supplied with heat using a hot air source, and the solder is melted by the heat. Preferably, the hot air source is kept running at a minimum wind speed. Specifically, the hot air source heats the solder for about 10s under the running condition of the minimum wind speed, so that the solder can be melted. The handle of the hot air source is continuously rocked, so that hot air is intermittently blown to the solder, and intermittent heat supply to the solder can be realized. For example, the number of times the hot air source is shaken is 5 to 15 times during the period in which the welding flux is heated. According to the welding method of the preferred technical scheme of the embodiment, intermittent heat supply is carried out on the welding flux, and a hot air source is kept to operate at the minimum wind speed, so that the problems that the welding flux gathers on the leeward side of a wire, and the welding flux on the windward side of the wire is too little, so that uniform ellipsoidal solder balls 102 are not formed can be avoided; meanwhile, intermittent heat supply can also avoid the problem that the soldering flux is invalid because the soldering flux is dried or volatilized due to overlarge heating.

Preferably, the included angle between the air outlet direction of the hot air source and the wire 101 to be welded is 30-60 degrees. When the included angle between the air outlet direction of the hot air source and the wire 101 to be soldered is too large, for example, 90 degrees, there is also a problem that the solder gathers on the leeward side of the wire, and the solder on the windward side of the wire is too small, which is not beneficial to forming uniform ellipsoidal solder balls 102; when the included angle between the air outlet direction of the hot air source and the wire 101 to be welded is too small, that is, the hot air source is too close to the wire 101 to be welded, the operation is inconvenient. According to the welding method of the preferred technical scheme of the embodiment, the included angle between the air outlet direction of the hot air source and the wire 101 to be welded is 30-60 degrees, so that uniform ellipsoidal solder balls 102 are formed, and the hot air can provide downward driving force for the solder, so that the solder is driven to move towards the direction close to the lower end part of the wire 101 to be welded.

According to a preferred embodiment, in step S300, when the wire 101 to be soldered is approaching to the pin to be soldered, the wire 101 to be soldered is located above the pin to be soldered, or the wire 101 to be soldered is located on the side of the pin to be soldered, and the wire 101 to be soldered is parallel to the pin to be soldered, or the angle between the wire 101 to be soldered and the pin to be soldered is smaller than 10 °. For the first type of chip pins, the schematic structure of the pins is shown in fig. 7, the type of pins 201 are fixed on the chip body 202, the pins 201 are in a vertical structure, the pins 201 include side pins 2011 and front pins 2012, and taking the side pins 2011 as pins to be soldered, it is easy to place the wires 101 to be soldered on or on the sides of the pins to be soldered. Preferably, when the pin 201 is in a vertical structure, the wire 101 to be soldered is placed on the side of the pin to be soldered, so that not only the connection reliability between the wire 101 to be soldered and the pin to be soldered can be enhanced, but also the problem that solder is blown onto the adjacent pin when hot air is blown to melt the solder balls again can be avoided. For the second type of chip pins, the pins 201 are fixed on the chip body 202, and the structure of the pins 201 is schematically shown in fig. 8, and the type of pins 201 has a pin inclined portion 201a and a pin horizontal portion 201b, and the wires 101 to be soldered are placed on the side of the pin inclined portion 201a, so that not only the wires 101 to be soldered can be conveniently placed, but also the wires 101 to be soldered are soldered on the side of the pins to be soldered, and the reliability of connection between the wires and the pins to be soldered can be enhanced.

Preferably, the vertical distance between the end of the wire 101 to be soldered and the pin to be soldered is 3-5 mm. Specifically, when the wire 101 to be soldered approaches to the pin to be soldered, positioning and aligning the pin to be soldered are performed first, then hot air is blown to melt the ellipsoidal solder balls 102, and then the wire 101 to be soldered is abutted to the pin to be soldered to complete soldering. According to the welding method of the preferred technical scheme of the embodiment, the vertical distance between the end part of the wire 101 to be welded and the pin to be welded is too large, so that hidden danger that solder drops onto other pins (when the wire 101 to be welded is positioned above the pin to be welded) is likely to occur, or the distance between the wire 101 to be welded and the pin adjacent to the pin to be welded is too small, so that the melted solder is likely to be connected with the other pins is likely to occur; the vertical distance between the end of the wire 101 to be soldered and the pin to be soldered is too small, and in the heating process, it is difficult to keep the wire 101 to be soldered still at the position all the time, and if not, the melted solder is easily connected with other pins, and hand-eye fatigue is also easily caused. According to the welding method of the preferred technical scheme of the embodiment, the vertical distance between the end part of the wire 101 to be welded and the pin to be welded is 3-5 mm, so that the wire 101 to be welded and the pin to be welded are accurately connected, and the welding operation can be enabled to have a good visual field.

According to a preferred embodiment, in step S300, the ellipsoidal solder balls 102 are intermittently or continuously heated using a hot air source based on at least one of the molten state of the ellipsoidal solder balls 102, the molten state of the pins to be soldered, the air speed of the heat gun, and the air speed of the soldering station, and the ellipsoidal solder balls 102 are remelted by the heat. Specifically, when the ellipsoidal solder balls 102 are heated, the molten state of the ellipsoidal solder balls 102 and the molten state of the pins to be soldered can be observed, and intermittent heating or continuous heating is selected in combination with the wind speed of the heat gun and/or the wind speed of the soldering station, so that the ellipsoidal solder balls 102 are melted again.

According to a preferred embodiment, the angle between the air outlet direction of the hot air source and the wire 101 to be soldered is 30-90 °. The included angle between the air outlet direction of the hot air source and the wire 101 to be welded, that is, the included angle between the central axis of the air outlet 301 of the hot air source and the wire 101 to be welded is specifically shown as α and β in fig. 7 and 8. The included angle between the air outlet direction of the hot air source and the wire 101 to be welded is too small, so that the operation is inconvenient, the pin to be welded is heated uniformly, and the potential hazard of blowing off the ellipsoidal solder balls 102 from the wire can also exist; the included angle between the air outlet direction of the hot air source and the lead 101 to be welded is too large, so that the pin to be welded is not convenient to be heated uniformly, and meanwhile, the ellipsoidal solder balls 102 can be blown upwards, so that the distance between the ellipsoidal solder balls 102 and the pin to be welded is too large, and the hidden danger of subsequent welding is not facilitated. According to the welding method of the preferred technical scheme of the embodiment, the included angle between the air outlet direction of the hot air source and the wire 101 to be welded is 30-90 degrees, so that hot air can be blown to the ellipsoidal solder balls 102 and the pins to be welded simultaneously, and meanwhile, the ellipsoidal solder balls 102 and the pins to be welded can be heated uniformly, and the wire 101 to be welded and the pins to be welded can be welded conveniently.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element. Furthermore, it should be noted that the scope of the methods and apparatus in the embodiments of the present application is not limited to performing the functions in the order shown or discussed, but may also include performing the functions in a substantially simultaneous manner or in an opposite order depending on the functions involved, e.g., the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application.

Claims

1. The welding method of the high-density pins is characterized by comprising the following steps of:

2. The method of soldering a high-density lead according to claim 1, further comprising a step of preparing solder before step S100, and the step of preparing solder comprises the steps of:

3. The method of soldering high-density pins according to claim 1, further comprising the steps of cooling the ellipsoidal solder balls for 1-3 seconds and solidifying the ellipsoidal solder balls before bringing the wire to be soldered closer to the pins to be soldered.

4. A method of soldering high density pins according to any one of claims 1 to 3, wherein in step S100, the flux is a paste; the weight ratio of the soldering flux to the solder is 1:1-1:2.

5. A method of soldering a high density pin according to any one of claims 1 to 3, further comprising the step of, in step S200: and vertically placing the wire to be welded, observing whether the molten solder is positioned at the end part of the wire to be welded, and cutting off and/or supplementing redundant parts of the end part of the wire to be welded when the molten solder lower end part is positioned above the end part of the wire to be welded and the distance between the molten solder lower end part and the end part of the wire to be welded exceeds a preset length.

6. The method of soldering high density pins according to claim 5, wherein the formulation used for the feed-through includes a flux and a solder, and wherein the weight ratio of flux to solder is 1:1-1:2.

7. A method of soldering high density pins according to any one of claims 1 to 3, wherein in step S200, the solder is intermittently supplied with heat using a hot air source, the solder is melted by the heat, and

the hot air source keeps running at the minimum wind speed,

the included angle between the air outlet direction of the hot air source and the wire to be welded is 30-60 degrees.

8. A method of soldering high density pins according to any one of claims 1 to 3, wherein in step S300, when the wire to be soldered is brought close to the pin to be soldered, the wire to be soldered is located above the pin to be soldered or the wire to be soldered is located on the side of the pin to be soldered, and

the vertical distance between the end of the wire to be welded and the pin to be welded is 3-5 mm,

the wire to be welded is parallel to the pin to be welded, or the included angle between the wire to be welded and the pin to be welded is smaller than 10 degrees.

9. A method of soldering high density pins according to any one of claims 1 to 3, wherein in step S300, the ellipsoidal solder balls are intermittently or continuously heated using a hot air source based on at least one of the molten state of the ellipsoidal solder balls, the molten state of the pins to be soldered, the wind speed of the hot air gun, and the wind speed of the soldering station, and the ellipsoidal solder balls are remelted by the heat.

10. The method of soldering high-density pins according to claim 9, wherein an included angle between an air outlet direction of the hot air source and the wire to be soldered is 30-90 °.