WO2018036202A1

WO2018036202A1 - Method for non-contact heating and tin brazing of metal structural member and pcb

Info

Publication number: WO2018036202A1
Application number: PCT/CN2017/083221
Authority: WO
Inventors: 吕晓胜; 郭林波; 王文长; 孙善球; 刘海滨; 朱龙翔; 岳德周
Original assignee: 京信通信技术(广州)有限公司; 京信通信系统（中国）有限公司; 天津京信通信系统有限公司
Priority date: 2016-08-22
Filing date: 2017-05-05
Publication date: 2018-03-01
Also published as: CN106238848B; CN106238848A

Abstract

Provided is a method for non-contact overall heating and tin brazing of a metal structural member and PCB, comprising the following steps: placing a workpiece on a drive system and transferring said workpiece to a heating system by means of the drive system, the workpiece being a joint body consisting of a metal structural member, PCB, weld, and a rotation fixture; heating the workpiece by non-contact thermal radiation of the entire body, causing the weld on the workpiece to melt; cooling the workpiece on which heating and welding has been completed, such that the molten weld rapidly solidifies into a desired weld point. The welded components are fixed, weld material is added, the weld is heated, and splitting is performed to establish two different processes, and a fine division of process steps is advantageous to the automation of each of the process steps, achieving modularized management.

Description

Non-contact heating tin brazing method for metal structural parts and PCB

Technical field

The invention relates to the field of processing technology, in particular to a welding related technology in the field of communication technology, in particular to a non-contact integral heating tin brazing method for a metal structural member and a PCB.

Background technique

The base station antenna is a key component of the coverage of the mobile communication network. The base station antenna is composed of a main feed end and a plurality of terminal components, and the metal structural member and the PCB component are the intermediate bridge between the main feed end and the terminal component, and the metal structural member. The connection to the PCB is typically tin brazing. The combination of PCB and metal structural parts is a grounding effect, and grounding is a very important indicator in the communications industry. Grounding technology is an important technology that must be taken when any electronic or electrical equipment or system works normally. It is not only a necessary means to protect equipment and personal safety, but also to suppress electromagnetic interference, ensure electromagnetic compatibility of equipment or systems, and improve equipment or system reliability. Important technical measures. If the grounding is poor, the entire base station antenna will be unstable, and the poor handling will even harm the entire base station system. In order to ensure good electrical connection conduction performance and structural connection stability, there are stringent requirements for the solder amount uniformity, solder joint penetration and mechanical strength.

As is known, the conventional tin brazing process is a local heating welding method in which a soldering iron is heated to conduct heat to the soldered contact point and to assist the solder wire to fill the solder. The welding method of the metal structural parts of the communication industry is basically welded by the electric soldering iron. However, due to the heat absorbing effect of the metal structural parts, in order to make the heating meet the welding demand, high temperature transfer or long-time contact welding is required. High-power soldering station must be used, and the long-term high temperature accelerates the oxidation of the soldering iron tip, and the service life of the soldering iron is greatly reduced. At the same time, the uneven heating of the soldering joint can not ensure the consistency of the soldering temperature, which leads to the decline of soldering quality reliability. On the other hand, the manual welding method can not guarantee the consistency of the welding time and the amount of tin delivered, the quality consistency is poor, and the operation mode is inefficient.

The components composed of metal structural parts and PCBs are used in a base station antenna, and the number of solder joints of a single product is dense. Due to the limitations of manual welding, it is inevitable that there will be virtual welding and leakage welding. The phenomenon. To achieve its fully automated welding, it is basically impossible on the basis of the prior art.

The industry has also made some attempts to use a three-dimensional robot to drive the soldering iron for positioning welding, which can solve the quantitative control of the tin feeding and welding time to a certain extent, but in principle, it cannot solve the heat absorption effect brought by the metal structural parts. The resulting solder joint reliability problem.

Summary of the invention

The object of the present invention is to provide a non-contact heating tin brazing method for a metal structural member and a PCB which improve welding efficiency and ensure welding quality.

In order to achieve the above object, the present invention provides the following technical solutions:

A non-contact heating tin brazing method for a metal structural member and a PCB, comprising an integral heating welding device having a transmission system and a heating system and a cooling system disposed in sequence along the workpiece driving direction, the method comprising the following steps: on the transmission system Placing the workpiece and transferring the workpiece to the heating system through a transmission system, the workpiece being a common body composed of a metal structural member, a PCB, a solder, and a turnover jig; the non-contact heat radiation is integrally heated to melt the solder on the workpiece The workpiece that is heated and welded is cooled to rapidly solidify the molten solder into the desired solder joint.

Further, the tin brazing method further includes the step of presetting the workpiece, specifically comprising: placing and locating the metal structural member on the revolving fixture having the limiting and positioning functions; and spacing the PCB from the metal structural member Assembly; solder pre-positioning of the solder joint between the metal structural member and the PCB; after the solder preset is completed, the metal structural member and the PCB are secondarily assembled.

Preferably, in the step of assembling the PCB to the metal structural member, the PCB is smoothly fixed to the metal structural member by means of the support.

Preferably, in the step of assembling the PCB into the gap between the metal structural members, the plurality of PCBs are divided into the positive and negative surfaces and placed in the molding tool with a predetermined gap, thereby being integrally assembled with the metal structural member.

Preferably, the solder is added to the solder joint between the metal structural member and the PCB by a stereo solder automatic adding device.

Preferably, in the step of performing non-contact thermal radiation heating on the workpiece, the heating region is partitioned such that the temperature of the region where the non-soldering portion of the PCB is located is lower than the temperature of the region where the solder joint portion is located.

Further, the heating regions are layered such that the temperature of the layer on which the lower surface of the PCB is located is lower than the temperature of the layer on which the upper surface is located.

Preferably, the tin brazing method further comprises a subsequent step, specifically comprising: removing the finished finished product from the revolving jig and returning the revolving jig through the transmission system.

Compared with the prior art, the solution of the invention has the following advantages:

1. In the non-contact integral heating welding method of the metal structural member and the PCB of the present invention, the welding device is fixed, the solder is added, and the heating and welding are split, and different processes are set up, and the precise division of labor facilitates automation of each process and realizes the module. Management.

2. In the tin brazing method of the present invention, after the relative position of the metal structural member and the PCB is fixed, the solder joint is uniformly pre-soldered, and then the non-contact program controlled heating is performed as a whole, and the solder is integrally completed in the integral heating and soldering device. Preheating, melting, welding, cooling, tin brazing is not affected by the number of solder joints and the size of the soldering device. The solder flow is more uniform and the wetting is more sufficient, which ensures the welding quality of the metal structural parts and the PCB, and improves the welding efficiency. .

The additional aspects and advantages of the invention will be set forth in part in the description which follows.

DRAWINGS

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from

Figure 1 is a schematic view of an embodiment of the present invention for heat welding of a workpiece in an integral heating and welding apparatus;

2 is a schematic view of another embodiment of the present invention for heat welding of a workpiece in an integral heating and welding apparatus.

detailed description

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the accompanying drawings, in which the same or Functional components. The embodiments described below with reference to the drawings are intended to be illustrative of the invention and are not to be construed as limiting.

The non-contact integral heating tin brazing method (hereinafter referred to as "tin brazing method") of the metal structural member and the coaxial cable of the invention mainly comprises a preset workpiece (including solder addition), a non-contact heating workpiece, a cooling workpiece, Four steps of disassembling the workpiece are carried out by fixing the welding device, soldering, heating and welding, setting up different processes and finely controlling them, facilitating the automatic completion of the welding process and realizing modular management.

Among them, the solder is added in the stereo soldering automatic adding device, which can realize the synchronous multi-point addition of the solder at the solder joints of many required soldering, so that the solder has accurate quantification and the solder shape is moved to ensure the welding process. The flow distance of the solder is consistent.

The non-contact heating is performed in an integral heating welding device having a transmission system for transmitting the workpiece and sequentially providing a heating system and a cooling system along the workpiece transmission direction, and the heating system is used for 360-degree full working of the workpiece The heat radiation makes the product evenly heated in each orientation and position, so that the solder on the solder joint is fully absorbed and melted, and then the solder joint between the metal structural member and the coaxial cable is wetted and flowed. Cooling is then performed so that the liquid solder at the solder joint rapidly solidifies to form the desired solder joint.

The integral heating and welding device of the present invention transfers heat by means of heat radiation, and the heating elements thereof include, but are not limited to, infrared heating, heating tube heating, laser heating, and the like, and the heating orientation is not limited to upper heating, lower heating, or Heating up and down, can be heated simultaneously in multiple directions.

Embodiment 1

The preset workpiece step specifically includes:

The metal structural member is taken out from the turnover box and placed on a revolving jig having a limit and positioning function, so that the metal structural member is placed in a predetermined position.

Insert the gap assembly between the PCB and the metal structural member; ensure that the PCB is surrounded by a platform-type support member to securely fix the PCB to the metal structural member. The support member adopts a multi-array integral structure fixing manner, can ensure the state of each PCB and the metal structural member after assembly, and provides effective and reliable fixation of a plurality of orientations to ensure the consistency of the welding effect. The support member has high temperature resistance characteristics, prevents the support failure of the whole heating process due to the thermal expansion and contraction effect of the object itself, and the support member has the characteristics of fast pick and place.

The metal structure of the PCB is fixed together with the revolving jig and placed in a stereo solder automatic adding device for solder presetting. The solder auto-addition device allows for simultaneous solder multi-point addition to the solder joints to be soldered, with precise solder addition and consistent solder shape to ensure consistent solder flow distance during soldering.

The metal structure of the solder preset and the semi-finished product of the PCB will be completed and then assembled twice.

Thereby, the preset process of the workpiece is completed, wherein the workpiece is a community composed of a metal structural member, a PCB, a solder and a turnover jig.

The semi-finished semi-finished product together with the revolving jig is placed in an integral heating welding device, heated by the heating system on the principle of heat radiation, and cooled by a cooling system.

As shown in FIG. 1 , the heating system performs 360-degree heat transfer on the metal structural member and the PCB, so that each orientation and location of the product can be uniformly heated, so that the solder on the solder joint is fully absorbed and melted. And further, wetting and flowing between the metal structural member and the solder joint of the PCB; in addition, the solder passes through the through-hole flow path on the PCB, and the other side of the PCB flows through the via hole, and the through hole of the metal structural member and the PCB The element is diffused between the solder joint and the plating layer to form a corresponding tin-copper alloy layer.

The cooling system of the integral heating and welding device cools the workpiece that is heated and welded by, for example, air cooling, and completes the entire non-contact tin brazing.

This type of integral heat welding device is capable of setting welding parameters (temperature, time, etc.). In order to ensure the temperature resistance of the PCB, the temperature of the welding area is hierarchically and properly set. First, the peripheral heating at the non-soldering portion of the PCB is 5-10 °C lower than the temperature of the solder joint area (the solder joint 3 and the solder joint 4 in Fig. 1) to avoid deformation of the PCB due to excessive heating; secondly, it is placed at The solder joint temperature of the layer on the upper surface of the PCB is about 5 °C higher than the solder joint of the layer on the lower surface of the PCB. With a small temperature difference, the solder has a flowability in a certain range from a low temperature to a high temperature.

In addition, the method further comprises removing the finished product of the welded metal structure from the turnover jig and returning the revolving jig through the pipeline to complete the whole single cycle process.

Embodiment 2

As shown in FIG. 2, the tin brazing method of the first embodiment is similar to that of the first embodiment, and is different in the preset process of the workpiece. Specifically embodied in:

In this embodiment, the PCB is first taken out of the turnover box, and the corresponding front and back sides are zoned. Of course After that, the side of the PCB to be soldered is placed on a revolving fixture with a predetermined function. At the same time, all the PCB boards are correspondingly positioned by the die tooling. Through the structural pre-positioning of the stamping tooling, the effective and reliable fixing of multiple PCBs can be ensured, and the mutual position between the PCBs is not more than ±0.1 mm to ensure the consistency of the welding effect. The pre-positioning function of the stamping tool has high temperature resistance to prevent deformation of the positioned PCB due to the thermal expansion and contraction effect of the object itself.

Accordingly, after the completion of the solder presetting process, before the secondary assembly, a demolding process is also included.

Similarly, in order to ensure the temperature resistance of the PCB, the temperature of the welding area is hierarchically and rationally set. First, the peripheral heating at the non-soldering portion of the PCB is 5-10 °C lower than the temperature of the solder joint area (the area of the solder joint 3 to 10 in Fig. 1) to avoid deformation of the PCB due to excessive heating; secondly, it is placed on the PCB. The solder joint temperature of the surface is about 5 °C higher than the solder joint on the lower surface of the PCB. With a small temperature difference, the solder has a flowability in a certain range from a low temperature to a high temperature.

The above is only a part of the embodiments of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention.

Claims

A non-contact heating tin brazing method for a metal structural member and a PCB, characterized in that it comprises an integral heating welding device having a transmission system and a heating system and a cooling system arranged in sequence along the workpiece transmission direction, the method comprising the steps of:

Positioning the workpiece on the transmission system and transmitting the workpiece to the heating system through a transmission system, the workpiece being a community of metal structural members, PCB, solder, and a turnover fixture;

Non-contact thermal radiation heating of the workpiece to melt the solder on the workpiece;

The workpiece that is heated and welded is cooled to rapidly solidify the molten solder into the desired solder joint.
The method of non-contact heating tin brazing of a metal structural member and a PCB according to claim 1, further comprising the step of presetting a workpiece, specifically comprising:

Place metal structural members on the revolving fixture with limit and positioning functions and position and position them;

Assembling the PCB from the metal structural member;

Solder presetting the solder joint between the metal structural member and the PCB;

After the solder preset is completed, the metal structural member and the PCB are secondarily assembled.
The method of non-contact heating tin brazing of a metal structural member and a PCB according to claim 2, wherein in the step of assembling the PCB and the metal structural member, the PCB is smoothly fixed on the metal structural member by means of the support member. .
The method of non-contact heating tin brazing of a metal structural member and a PCB according to claim 2, wherein in the step of assembling the PCB and the metal structural member, the plurality of PCBs are divided into front and back surfaces and placed in a predetermined gap. In the mold assembly, the whole is assembled with the metal structural member.
The method of non-contact heating tin brazing of a metal structural member and a PCB according to claim 2, wherein the solder is added to a solder joint between the metal structural member and the PCB by a stereoscopic solder automatic adding device.
The non-contact heating tin brazing method for a metal structural member and a PCB according to claim 1, wherein in the step of performing non-contact thermal radiation heating on the workpiece, the heating region is partitioned so that the PCB is not The area where the solder joint is located and the area where the solder joint is located There is a temperature difference.
The method of non-contact heating tin brazing of a metal structural member and a PCB according to claim 6, wherein in the step of performing non-contact thermal radiation heating on the workpiece, the heating region is layered to make the PCB There is a temperature difference between the layer on the lower surface and the layer on the upper surface.
The non-contact heating tin brazing method for a metal structural member and a PCB according to claim 1, further comprising a subsequent step, comprising: removing the finished finished product from the revolving jig and returning it through the transmission system Turnover fixture.