WO2024099439A1

WO2024099439A1 - Through hole reflow soldering method

Info

Publication number: WO2024099439A1
Application number: PCT/CN2023/131052
Authority: WO
Inventors: 尹向阳; 张洪祥
Original assignee: 广州金升阳科技有限公司
Priority date: 2022-11-11
Filing date: 2023-11-10
Publication date: 2024-05-16
Also published as: CN115673456A

Abstract

The present invention provides a through hole reflow soldering method. The through hole reflow soldering method comprises: placing multiple parts to be soldered on multiple bearing positions of a through hole reflow soldering device; performing detection on the multiple bearing positions of the through hole reflow soldering device, to obtain vacant bearing position information, the vacant bearing position information comprising the location of a vacant bearing position; performing a through hole closing operation on the vacant bearing position according to the vacant bearing position information; and performing a soldering operation by means of the through hole reflow soldering device loaded with the multiple parts. According to a technical solution provided by the present application, the problem of a through hole reflow soldering method in the prior art easily damaging an element on a part to be soldered may be solved.

Description

Through-hole reflow soldering method

Technical Field

The invention relates to the technical field of through-hole reflow soldering, and in particular to a soldering method for through-hole reflow soldering.

Background technique

In recent years, more and more attention has been paid to miniaturization, multi-function and close arrangement of components. Compared with SMD components, plug-in components have the advantages of high strength, high reliability and wide applicability. Therefore, the parts to be welded are plug-in components on the PCB board. Compared with SMD components, plug-in components involve additional processing steps. The through-hole reflow process can realize the reflow of through-hole devices and SMD components in a single step, eliminating the subsequent additional processing steps.

In the related art, through-hole reflow soldering equipment uses a hot air pressure balance process to solder the parts to be soldered.

However, the through-hole reflow soldering method in the related art is prone to the shifting between hot air and cold air when soldering the workpiece to be soldered, so that the through-hole reflow soldering method in the related art is prone to damage the high-temperature-sensitive plug-in components on the workpiece to be soldered.

Summary of the invention

The invention provides a through-hole reflow soldering method to solve the problem that the through-hole reflow soldering method in the related art is easy to damage components on a to-be-soldered part.

The present invention provides a through-hole reflow soldering method, which includes: placing multiple parts to be soldered on multiple carrying positions of a through-hole reflow soldering device; detecting the multiple carrying positions of the through-hole reflow soldering device to obtain vacant carrying position information, wherein the vacant carrying position information includes the positions of the vacant carrying positions; closing the through holes of the vacant carrying positions according to the vacant carrying position information; and performing a soldering operation using the through-hole reflow soldering device carrying the multiple parts to be soldered.

Furthermore, the step of performing the soldering operation by the through-hole reflow soldering equipment carrying a plurality of parts to be soldered includes: blowing hot air to the lower surface of the parts to be soldered, and blowing cold air to the upper surface of the parts to be soldered.

Further, the step of blowing hot air to the lower surface of the workpiece to be welded and blowing cold air to the upper surface of the workpiece to be welded comprises: firstly performing activation treatment on the workpiece to be welded, and the activation treatment on the workpiece to be welded comprises: blowing hot air to the lower surface of the workpiece to be welded and blowing cold air to the upper surface of the workpiece to be welded A first hot air is blown to the lower surface of the weldment, and a first cold air is blown or suctioned to the upper surface of the weldment; welding treatment is performed on the weldment to be welded after activation treatment, and the welding treatment includes blowing a second hot air to the lower surface of the weldment to be welded, and blowing a second cold air to the upper surface of the weldment to be welded, wherein the temperature of the second hot air is greater than the temperature of the first hot air, and the temperature of the second cold air is less than the temperature of the first cold air.

Furthermore, the steps of performing the welding treatment of the parts to be welded include: first performing a heating stage of the welding treatment of the parts to be welded, the heating stage includes blowing a second hot air toward the lower surface of the parts to be welded, blowing a second cold air toward the upper surface of the parts to be welded, and detecting the temperature of the upper surface of the parts to be welded; when the temperature of the lower surface of the parts to be welded is greater than the melting point temperature of the solder of the parts to be welded, performing a reflow stage of the welding treatment of the parts to be welded, the reflow stage includes blowing a second hot air toward the lower surface of the parts to be welded, blowing a second cold air toward the upper surface of the parts to be welded, detecting the temperature of the upper surface of the parts to be welded and the temperature of the lower surface of the parts to be welded, and adjusting the temperature of the second hot air and the temperature of the second cold air according to the temperature of the upper surface of the parts to be welded and the temperature of the lower surface of the parts to be welded.

Furthermore, the steps of adjusting the temperature of the second hot air and the temperature of the second cold air according to the temperature of the upper surface of the workpiece to be welded and the temperature of the lower surface of the workpiece to be welded include: when the temperature of the upper surface of the workpiece to be welded is greater than or equal to the temperature that the components of the workpiece to be welded can withstand, lowering the temperature of the second cold air until the temperature of the upper surface of the workpiece to be welded is less than the temperature that the components can withstand, and at this time maintaining the temperature of the second cold air at a current state; when the temperature of the lower surface of the workpiece to be welded is less than the melting point temperature of the solder of the workpiece to be welded, increasing the temperature of the second hot air until the temperature of the lower surface of the workpiece to be welded is greater than or equal to the melting point temperature, and at this time maintaining the temperature of the second hot air at a current state.

Furthermore, when performing welding treatment on the parts to be welded after activation treatment, the welding treatment includes the steps of blowing a second hot air toward the lower surface of the parts to be welded and blowing a second cold air toward the upper surface of the parts to be welded after activation treatment, the intensity of the second hot air is greater than the intensity of the first hot air, and the intensity of the second cold air is greater than the intensity of the first cold air.

Furthermore, the step of blowing hot air to the lower surface of the workpiece to be welded includes: blowing hot air to the lower surface of the workpiece to be welded by circulating heating and blowing.

Furthermore, the step of blowing cold air toward the upper surface of the workpiece to be welded includes: blowing cold air toward the upper surface of the workpiece to be welded so that the cold air exchanges heat with the upper surface of the workpiece to be welded; and discharging the cold air after the heat exchange from the through-hole reflow soldering equipment to the outside atmosphere.

Furthermore, the through-hole reflow soldering method also includes: blowing a first cooling air toward the lower surface of the workpiece to be soldered after the soldering operation is completed, and blowing a second cooling air toward the upper surface of the workpiece to be soldered, to perform a cooling operation on the workpiece to be soldered, wherein the temperature of the first cooling air and the temperature of the second cooling air are both lower than the temperature of the hot air and higher than the temperature of the cold air.

Further, in the step of blowing hot air toward the lower surface of the workpiece to be welded and blowing cold air toward the upper surface of the workpiece to be welded, the intensity of the hot air is the same as the intensity of the cold air.

By applying the technical solution of the present invention, multiple parts to be welded are placed on multiple bearing positions of a through-hole reflow soldering device, and each bearing position is placed with at most one part to be welded. The bearing positions without parts to be welded are regarded as vacant bearing positions, and the bearing state of each bearing position is detected to obtain the position of the vacant bearing position, and the through holes at the vacant bearing positions are closed, and the through holes at the bearing positions where parts to be welded are placed are opened, and the welding operation is performed using the through-hole reflow soldering device. By closing the through holes at the vacant bearing positions and opening the through holes at the bearing positions where parts to be welded are placed, during the welding operation, the parts to be welded are welded using the opened through holes at the welding positions where parts to be welded are placed, and at the vacant bearing positions, the closed through holes are used to isolate the upper furnace chamber and the lower furnace chamber of the through-hole reflow soldering, so as to avoid heat transfer between the upper furnace chamber and the lower furnace chamber at the welding positions where no welding operation is performed, and when the welding operation is subsequently performed at the welding positions, the temperature of the upper furnace chamber and the lower furnace chamber is reliable, and the temperature of the upper furnace chamber and the lower furnace chamber can protect the components of the parts to be welded from being damaged during the welding operation.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

FIG1 is a flow chart showing a through-hole reflow soldering method according to an embodiment of the present invention;

FIG. 2 shows another flow chart of a through-hole reflow soldering method according to an embodiment of the present invention;

FIG3 shows another flow chart of the through-hole reflow soldering method according to an embodiment of the present invention;

FIG4 is a schematic diagram showing a supporting position of a through-hole reflow soldering device according to an embodiment of the present invention;

FIG5 shows a schematic structural diagram of a through-hole reflow soldering device provided in an embodiment of the present invention;

FIG6 shows another schematic structural diagram of a through-hole reflow soldering device provided in an embodiment of the present invention;

FIG. 7 shows a graph showing the temperature and time of the upper surface of the workpiece to be welded and the temperature and time of the lower surface of the workpiece to be welded in the welding method of through-hole reflow welding provided by an embodiment of the present invention.

The above drawings include the following reference numerals:

10. Parts to be welded;

20. Through-hole reflow equipment; 21. Loading position; 211. Vacant loading position; 212. Through hole; 22. Transport track; 23. Upper furnace chamber; 24. Lower furnace chamber; 25. Heat insulation board; 251. Fixed board; 252. Movable board;

30. Hot air; 31. First hot air; 32. Second hot air;

40, cold wind; 41, first cold wind; 42, second cold wind;

51. first cooling air; 52. second cooling air;

61. Soldering operation; 611. Activation treatment; 612. Soldering treatment; 6121. Heating stage; 6122. Reflow stage; 62. Cooling operation;

S1, temperature-time curve of the lower surface of the welded part;

S2. Temperature-time curve of the upper surface of the workpiece to be welded.

Detailed ways

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

As shown in FIG. 1 to FIG. 7 , an embodiment of the present invention provides a through-hole reflow soldering method, and the through-hole reflow soldering method includes:

S100, placing a plurality of parts 10 to be welded on a plurality of carrying positions 21 of a through-hole reflow device 20;

S200, detecting a plurality of carrier positions 21 of the through-hole reflow soldering device 20 to obtain information of vacant carrier positions 211, wherein the information of vacant carrier positions 211 includes positions of the vacant carrier positions 211;

S300, closing the through hole 212 of the vacant carrying position 21 according to the information of the vacant carrying position 211;

S400 , performing a soldering operation 61 by using a through-hole reflow soldering device 20 carrying a plurality of components 10 to be soldered.

The through-hole reflow soldering method provided in the application embodiment is to place a plurality of parts to be soldered 10 on a plurality of carrier positions 21 of a through-hole reflow soldering device 20, with each carrier position 21 being provided with at most one part to be soldered 10, and to use the carrier positions 21 without the parts to be soldered 10 as vacant carrier positions 211, to detect the loading state of each carrier position 21, to obtain the position of the vacant carrier position 211, and to close the through-hole at the vacant carrier position 211. 212, open the through hole 212 at the support position 21 where the workpiece 10 to be welded is placed, and use the through hole reflow soldering equipment 20 to perform the welding operation 61. By closing the through hole 212 at the vacant support position 211 and opening the through hole 212 at the support position 21 where the workpiece 10 to be welded is placed, in the welding operation 61, the workpiece 10 to be welded is welded by using the opened through hole 212 at the welding position where the workpiece 10 to be welded is placed, and at the vacant support position 211, the closed through hole 212 is used to isolate the upper furnace chamber 23 and the lower furnace chamber 24 of the through hole reflow soldering, so as to avoid heat transfer between the upper furnace chamber 23 and the lower furnace chamber 24 at the welding position where the welding operation 61 is not performed, and when the welding operation 61 is subsequently performed at the welding position, the temperature of the upper furnace chamber 23 and the lower furnace chamber 24 is reliable, and the temperature of the upper furnace chamber 23 and the lower furnace chamber 24 can protect the components of the workpiece 10 to be welded from being damaged during the welding operation 61.

As shown in Figures 4 to 6, with the transport track 22 as the boundary, the cavity of the through-hole reflow soldering equipment 20 is divided into an upper furnace cavity 23 and a lower furnace cavity 24 by the insulation plate 25, wherein the insulation plate 25 includes a fixed plate 251 and a movable plate 252, the fixed plate 251 extends from the side wall of the transport track 22 to the inner wall of the cavity of the through-hole reflow soldering equipment 20, and a plurality of bearing positions 21 are arranged on the transport track 22, each bearing position 21 has a through hole 212 of the same size as the part to be soldered 10, and the movable plate 252 can be opened and closed below the through hole 212, the opened movable plate 252 can avoid the through hole 212, and the closed movable plate 252 can block the through hole 212.

As shown in FIG. 6 , step S400 of performing a soldering operation 61 by a through-hole reflow soldering device 20 carrying a plurality of components 10 to be soldered includes:

S410, hot air 30 is blown toward the lower surface of the workpiece 10 to be welded, and cold air 40 is blown toward the upper surface of the workpiece 10 to be welded. In the welding operation 61, hot air 30 is blown toward the lower surface of the workpiece 10 to be welded to heat the solder on the lower surface of the workpiece 10 to be welded, and at the same time, cold air 40 is blown toward the upper surface of the workpiece 10 to be welded to lower the temperature of the components on the upper surface of the workpiece 10 to be welded, so as to prevent the temperature of the components from exceeding the component bearing temperature, and to prevent the components of the workpiece to be welded from being damaged during the welding operation.

In this embodiment, the hot air 30 includes but is not limited to being provided by a hot air blowing device, an infrared device, and a gas phase device.

As shown in FIG. 2 , step S410 of blowing hot air 30 toward the lower surface of the workpiece 10 to be welded and blowing cold air 40 toward the upper surface of the workpiece 10 to be welded includes:

S411, firstly perform activation treatment 611 of the workpiece 10 to be welded, the activation treatment 611 of the workpiece 10 to be welded includes: blowing first hot air 31 to the lower surface of the workpiece 10 to be welded, and blowing first cold air 41 or suction air to the upper surface of the workpiece 10 to be welded;

S412, performing welding treatment 612 on the workpiece 10 to be welded after activation treatment 611, welding treatment 612 includes blowing second hot air 32 to the lower surface of the workpiece 10 to be welded, and blowing second cold air 42 to the upper surface of the workpiece 10 to be welded, wherein the temperature of the second hot air 32 is greater than the temperature of the first hot air 31, and the temperature of the second cold air 42 is less than the temperature of the first cold air 41. Firstly, the activation treatment 611 of the workpiece 10 to be welded is performed to increase the temperature of the workpiece 10 to be welded, and then the welding treatment 612 of the workpiece 10 to be welded is performed. Since the temperature of the second hot air 32 is greater than the temperature of the first hot air 31, the temperature of the workpiece 10 to be welded can be accelerated to melt the solder of the workpiece 10 to be welded, and since the temperature of the second cold air 42 is less than the temperature of the first cold air 41, in the welding treatment 612, the second cold air 42 is used to cool the workpiece 10 to be welded with a stronger cooling effect than the activation treatment 611, so as to prevent the temperature of the component from exceeding the component bearing temperature and to prevent the component of the workpiece 10 to be welded from being damaged.

In this embodiment, the first cold air 41 uses normal temperature air, so that in the activation process 611, air is sucked toward the upper surface of the workpiece 10 to be welded, so that the ambient normal temperature air enters from the gap of the through-hole reflow soldering equipment and contacts the upper surface of the workpiece 10 to be welded, and the cooling effect achieved is the same as the cooling effect achieved by blowing normal temperature air toward the upper surface of the workpiece 10 to be welded. The second cold air 42 includes but is not limited to being provided by a refrigeration device.

As shown in FIG. 2 , step S412 of performing the welding process 612 of the workpiece 10 to be welded includes:

S4121, firstly performing a heating stage 6121 of the welding process 612 of the workpiece 10 to be welded, the heating stage 6121 includes blowing a second hot air 32 to the lower surface of the workpiece 10 to be welded, blowing a second cold air 42 to the upper surface of the workpiece 10 to be welded, and detecting the temperature of the upper surface of the workpiece 10 to be welded;

S4122, when the temperature of the lower surface of the workpiece 10 to be welded is greater than the melting point temperature of the solder of the workpiece 10 to be welded, the reflow stage 6122 of the welding process 612 of the workpiece 10 to be welded is performed, and the reflow stage 6122 includes blowing the second hot air 32 to the lower surface of the workpiece 10 to be welded, blowing the second cold air 42 to the upper surface of the workpiece 10 to be welded, detecting the temperature of the upper surface of the workpiece 10 to be welded and the temperature of the lower surface of the workpiece 10 to be welded, and adjusting the temperature of the second hot air 32 and the temperature of the second cold air 42 according to the temperature of the upper surface of the workpiece 10 to be welded and the temperature of the lower surface of the workpiece 10 to be welded. In the temperature rising stage 6121, the temperature of the lower surface of the workpiece 10 to be welded rises rapidly to quickly reach the melting point temperature of the solder to achieve melting of the solder. In the reflow stage 6122, the temperature of the second hot air 32 and the temperature of the second cold air 42 are adjusted according to the temperature of the upper surface of the workpiece 10 to be welded and the temperature of the lower surface of the workpiece 10 to be welded to avoid solidification of the solder or damage to the components.

In this embodiment, step S4122 of adjusting the temperature of the second hot air 32 and the temperature of the second cold air 42 according to the temperature of the upper surface of the workpiece 10 to be welded and the temperature of the lower surface of the workpiece 10 to be welded includes:

S4123, when the temperature of the upper surface of the workpiece 10 to be welded is greater than or equal to the component bearing temperature of the workpiece 10 to be welded, the temperature of the second cold air 42 is lowered until the temperature of the upper surface of the workpiece 10 to be welded is less than the component bearing temperature, and at this time, the temperature of the second cold air 42 is maintained at the current state;

S4124, when the temperature of the lower surface of the workpiece 10 to be welded is lower than the melting point temperature of the solder of the workpiece 10 to be welded, the temperature of the second hot air 32 is increased until the temperature of the lower surface of the workpiece 10 to be welded is greater than or equal to the melting point temperature, and at this time, the temperature of the second hot air 32 is maintained at the current state. In the reflow soldering stage 6122, when the temperature of the upper surface of the workpiece 10 to be welded is greater than or equal to the component bearing temperature of the workpiece 10 to be welded, the temperature of the second cold air 42 is lowered to improve the heat dissipation effect on the component, and the temperature of the upper surface of the workpiece 10 to be welded is reduced to below the component bearing temperature, and at this time, the temperature of the second cold air 42 is maintained, so as to protect the component while preventing the temperature of the second cold air 42 from being too low so that the solder solidifies and cannot be welded. When the temperature of the lower surface of the workpiece 10 to be welded is lower than the melting point, the temperature of the second hot air 32 is increased to improve the heating effect on the workpiece to be welded. When the temperature of the lower surface of the workpiece 10 to be welded is increased to a temperature greater than or equal to the melting point, the temperature of the second hot air 32 is maintained, thereby melting the solder while avoiding overheating and damage to the components caused by excessive temperature of the second hot air 32.

As shown in FIG5 , in the step S410 of performing welding treatment 612 on the workpiece 10 to be welded after activation treatment 611, welding treatment 612 includes blowing second hot air 32 to the lower surface of the workpiece 10 to be welded and blowing second cold air 42 to the upper surface of the workpiece 10 to be welded after activation treatment 611, the intensity of the second hot air 32 is greater than the intensity of the first hot air 31, and the intensity of the second cold air 42 is greater than the intensity of the first cold air 41. Compared with the activation treatment 611, the difference in the intensity of the second hot air 32 and the first hot air 31, and the difference in the intensity of the second cold air 42 and the first cold air 41, make the heating effect of the second hot air 32 of the welding treatment 612 stronger than the hot effect of the first hot air 31, and the heat dissipation effect of the second cold air 42 is stronger than the heat dissipation effect of the first cold air 41, so that while the solder of the workpiece 10 to be welded is rapidly melted, the components are prevented from being damaged by overheating.

As shown in FIG. 6 , the step S400 of blowing hot air 30 toward the lower surface of the workpiece 10 to be welded includes:

The hot air 30 is blown to the lower surface of the workpiece 10 to be welded by a circulating heating and blowing method. By adopting the above-mentioned circulating heating and blowing method, the hot air 30 that has come into contact with the workpiece 10 to be welded is recovered and reheated. Compared with the air at normal temperature, the temperature of the recovered hot air 30 is higher, and the energy consumption required for the recovered hot air 30 during the heating process is smaller, thereby saving energy use.

As shown in FIG. 5 , the step S400 of blowing cold air 40 toward the upper surface of the workpiece 10 to be welded includes:

Blowing the cold air 40 toward the upper surface of the workpiece 10 to be welded, so that the cold air 40 and the upper surface of the workpiece 10 to be welded perform heat exchange;

The cold air 40 after heat exchange is discharged from the through-hole reflow soldering device 20 to the outside atmosphere. Compared with the air at normal temperature, the temperature of the cold air 40 after heat exchange is higher, and the energy consumption required for the cold air 40 after heat exchange in the cooling process is greater, so the cold air 40 after heat exchange is discharged from the through-hole reflow soldering device 20 to the outside atmosphere, which can save energy.

In this embodiment, the through-hole reflow soldering method further includes:

S500, blowing the first cooling air 51 to the lower surface of the workpiece 10 to be welded after the welding operation 61 is completed, and blowing the second cooling air 52 to the upper surface of the workpiece 10 to be welded, and performing the cooling operation 62 of the workpiece 10 to be welded, wherein the temperature of the first cooling air 51 and the temperature of the second cooling air 52 are both lower than the temperature of the hot air 30 and higher than the temperature of the cold air 40. In the cooling operation 62, the first cooling air 51 and the second cooling air 52 are used to cool down the workpiece 10 to be welded. Since the temperature of the first cooling air 51 and the temperature of the second cooling air 52 are both lower than the temperature of the hot air 30 and higher than the temperature of the cold air 40, on the one hand, it can increase the time taken for the workpiece 10 to be welded to cool down to normal temperature after the welding operation 61, and improve the welding efficiency of the through-hole reflow soldering method. On the other hand, it can avoid the temperature of the first cooling air 51 and the second cooling air 52 being too low, and avoid the solder on the lower surface of the workpiece 10 to be welded from cracking during the cooling process, so as to improve the welding effect of the through-hole reflow soldering method.

As shown in Fig. 4, in step S410 of blowing hot air 30 to the lower surface of the workpiece 10 to be welded and blowing cold air 40 to the upper surface of the workpiece 10 to be welded, the intensity of the hot air 30 is the same as the intensity of the cold air 40. Since the intensity of the hot air 30 is the same as the intensity of the cold air 40, the hot air 30 and the cold air 40 form a wind wall between the upper surface and the lower surface of the workpiece 10 to be welded, avoiding direct contact between the hot air 30 and the upper surface of the workpiece 10 to be welded, and avoiding direct contact between the cold air 40 and the lower surface of the workpiece 10 to be welded, thereby ensuring the normal operation of the welding operation 61.

In this embodiment, the temperature-time curve of the upper surface of the workpiece to be welded and the temperature-time curve of the lower surface of the workpiece to be welded are shown in FIG. 7 . The peak temperature of the lower surface of the workpiece to be welded 10 in the reflow stage 6122 is greater than the melting point of the solder by more than 10°C, and the duration is greater than 20 seconds. During the entire welding operation 61 and the cooling operation 62, the temperature of the upper surface of the workpiece to be welded 10 is always lower than the withstand temperature of the component. Among them, S1 is the temperature-time curve of the lower surface of the workpiece to be welded 10, and S2 is the temperature-time curve of the upper surface of the workpiece to be welded 10.

It should be noted that the through-hole reflow soldering method in the prior art has the following two comparative examples:

(1) In comparative example 1, a low temperature solder (such as Sn58Bi42) is used;

(2) In comparative example 2, a reflow oven without heating the upper chamber is used. Cold air is blown into the upper chamber to form convection pressure in the chamber, thereby preventing hot air from the lower chamber from escaping to the upper chamber. This results in a certain temperature difference on the circuit board or PCB.

In comparative example 1, the melting point of the low-temperature solder is as high as 139°C. During reflow soldering, it is necessary to ensure that the solder joint temperature on the lower surface of the component 10 to be soldered is 10°C to 30°C higher than the melting point temperature. The solder joint temperature is higher than the withstand temperature of general plug-in components (120°C), and the main component of the low-temperature solder is Bi element, which makes the solder joint brittle, resulting in reduced solder joint quality and reliability, which brings hidden dangers.

In Comparative Example 2, since the workpiece 10 to be welded is always in motion and has a different structural shape, it is impossible to accurately control the temperature of the upper and lower furnace chambers and the wind intensity, resulting in unstable temperature inside the cavity of the through-hole reflow soldering equipment. At most, the temperature of the upper surface of the workpiece to be welded can be 50°C to 80°C lower than the temperature of its lower surface, making it impossible for the temperature of the component to be reduced below the component's tolerance temperature (120°C), causing damage to the component.

In this embodiment, the technical solution provided in this embodiment is applied to increase the temperature of the solder joint on the lower surface of the workpiece 10 to be welded and reduce the temperature of the components on the upper surface of the workpiece 10 to be welded, thereby increasing the temperature difference between the upper surface and the lower surface of the workpiece 10 to be welded, so that the temperature difference can reach above 150°C. Compared with Comparative Examples 1 and 2, when using room temperature solder (SAC305) with a melting point of 215°C, this embodiment can make the temperature of the lower surface of the workpiece 10 to be welded above 240°C while ensuring that the temperature of the upper surface of the workpiece 10 to be welded is lower than 120°C, so as to meet the bearing temperature of most components, so that through-hole reflow soldering can use room temperature solder and avoid components from being subjected to high temperatures.

It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and/or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and/or combinations thereof.

Unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values described in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and devices known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, The technology, method and apparatus should be considered as part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

A through-hole reflow soldering method, characterized in that the through-hole reflow soldering method comprises:

Placing a plurality of parts to be welded (10) on a plurality of carrying positions (21) of a through-hole reflow soldering device (20);

Detecting a plurality of the carrying positions (21) of the through-hole reflow soldering equipment (20) to obtain vacant carrying position (211) information, wherein the vacant carrying position (211) information includes positions of the vacant carrying positions (211);

Performing a closing operation on the through hole (212) of the vacant carrying position (211) according to the information of the vacant carrying position (211);

A welding operation (61) is performed by a through-hole reflow soldering device (20) carrying a plurality of the components (10) to be welded.
The through-hole reflow soldering method according to claim 1, characterized in that the step of performing a soldering operation (61) by means of a through-hole reflow soldering device (20) carrying a plurality of the parts to be soldered (10) comprises:

Hot air (30) is blown toward the lower surface of the workpiece (10) to be welded, and cold air (40) is blown toward the upper surface of the workpiece (10) to be welded.
The through-hole reflow soldering method according to claim 2 is characterized in that the step of blowing hot air (30) toward the lower surface of the workpiece (10) to be soldered and blowing cold air (40) toward the upper surface of the workpiece (10) to be soldered comprises:

First, an activation treatment (611) is performed on the workpiece (10) to be welded, and the activation treatment (611) of the workpiece (10) to be welded includes: blowing a first hot air (31) toward the lower surface of the workpiece (10) to be welded, and blowing a first cold air (41) or suction air toward the upper surface of the workpiece (10) to be welded;

A welding process (612) is performed on the workpiece to be welded (10) after the activation process (611), and the welding process (612) includes blowing a second hot air (32) toward the lower surface of the workpiece to be welded (10), and blowing a second cold air (42) toward the upper surface of the workpiece to be welded (10), wherein the temperature of the second hot air (32) is greater than the temperature of the first hot air (31), and the temperature of the second cold air (42) is less than the temperature of the first cold air (41).
The through-hole reflow soldering method according to claim 3 is characterized in that the step of performing a soldering process (612) on the workpiece (10) to be soldered comprises:

First, the temperature rise stage (6121) of the welding process (612) of the workpiece (10) to be welded is performed, wherein the temperature rise stage (6121) includes blowing the second hot air (32) toward the lower surface of the workpiece (10) to be welded, Blowing the second cold air (42) toward the upper surface of the workpiece (10) to be welded, and detecting the temperature of the upper surface of the workpiece (10) to be welded;

When the temperature of the lower surface of the part to be welded (10) is greater than the melting point of the solder of the part to be welded (10), the reflow stage (6122) of the welding process (612) of the part to be welded (10) is performed, and the reflow stage (6122) includes blowing the second hot air (32) toward the lower surface of the part to be welded (10), blowing the second cold air (42) toward the upper surface of the part to be welded (10), detecting the temperature of the upper surface of the part to be welded (10) and the temperature of the lower surface of the part to be welded (10), and adjusting the temperature of the second hot air (32) and the temperature of the second cold air (42) according to the temperature of the upper surface of the part to be welded (10) and the temperature of the lower surface of the part to be welded (10).
The through-hole reflow soldering method according to claim 4 is characterized in that the step of adjusting the temperature of the second hot air (32) and the temperature of the second cold air (42) according to the temperature of the upper surface of the workpiece (10) to be soldered and the temperature of the lower surface of the workpiece (10) to be soldered comprises:

When the temperature of the upper surface of the workpiece (10) to be welded is greater than or equal to the component bearing temperature of the workpiece (10) to be welded, the temperature of the second cold air (42) is lowered until the temperature of the upper surface of the workpiece (10) to be welded is less than the component bearing temperature, and at this time, the temperature of the second cold air (42) is maintained at the current state;

When the temperature of the lower surface of the workpiece (10) to be welded is lower than the melting point temperature of the solder of the workpiece (10), the temperature of the second hot air (32) is increased until the temperature of the lower surface of the workpiece (10) to be welded is greater than or equal to the melting point temperature, and at this time, the temperature of the second hot air (32) is maintained at the current state.
The through-hole reflow soldering method according to claim 3 is characterized in that, when performing a soldering treatment (612) on the workpiece to be soldered (10) after the activation treatment (611), the soldering treatment (612) includes blowing the second hot air (32) toward the lower surface of the workpiece to be soldered (10), and blowing the second cold air (42) toward the upper surface of the workpiece to be soldered (10) after the activation treatment (611), the intensity of the second hot air (32) is greater than the intensity of the first hot air (31), and the intensity of the second cold air (42) is greater than the intensity of the first cold air (41).
The through-hole reflow soldering method according to any one of claims 2 to 6 is characterized in that the step of blowing hot air (30) toward the lower surface of the workpiece (10) to be soldered comprises:

Hot air (30) is blown onto the lower surface of the workpiece (10) to be welded by means of a circulating heating and blowing method.
The through-hole reflow soldering method according to any one of claims 2 to 6 is characterized in that the step of blowing cold air (40) toward the upper surface of the workpiece (10) to be soldered comprises:

Blowing the cold air (40) toward the upper surface of the workpiece (10) to be welded, so that the cold air (40) and the upper surface of the workpiece (10) to be welded can exchange heat;

The cold air (40) after the heat exchange is discharged from the through-hole reflow soldering equipment (20) to the outside atmosphere.
The through-hole reflow soldering method according to any one of claims 2 to 6, characterized in that the through-hole reflow soldering method further comprises:

After the welding operation (61) is completed, a first cooling air (51) is blown toward the lower surface of the workpiece (10) to be welded, and at the same time, a second cooling air (52) is blown toward the upper surface of the workpiece (10) to perform a cooling operation (62) on the workpiece (10) to be welded, wherein the temperature of the first cooling air (51) and the temperature of the second cooling air (52) are both lower than the temperature of the hot air (30) and higher than the temperature of the cold air (40).
The through-hole reflow soldering method according to any one of claims 2 to 6 is characterized in that, in the step of blowing hot air (30) toward the lower surface of the workpiece (10) to be soldered and blowing cold air (40) toward the upper surface of the workpiece (10) to be soldered, the intensity of the hot air (30) and the intensity of the cold air (40) are the same.