TW202247934A - Welding method can concentrate the high-temperature airflow on the welding material on the circuit board to reduce the impact on the electronic components mounted on the circuit board - Google Patents

Abstract

This invention provides a welding method including the following steps: providing a circuit board, an electronic component and a heating apparatus, wherein the circuit board is provided with a plurality of conductive through holes and a plurality of welding pads connected to the conductive through holes, the electronic component is provided with a plurality of leads, and the heating apparatus includes a nozzle part; enabling the plurality of leads of the electronic component to respectively pass through the conductive through holes in the bottom of the circuit board and respectively protrude out of the welding pads; forming a plurality of welding materials on the welding pads and the corresponding leads, and filling the welding materials between each of the conductive through holes and each of the corresponding leads; and delivering a high-temperature gas flow from the nozzle part to heat the welding materials so that the welding materials reach welding temperatures, then, respectively welding the leads in the conductive through holes, and thus, the electronic component is electrically connected to the circuit board.

Description

Welding method

The invention provides a welding method, especially a welding method which uses high-temperature gas flow to heat welding materials for welding.

Surface Mount Technology (Surface Mount Technology) is a soldering technology that combines electronic components on a circuit board. Specifically, surface mount technology is to print solder paste on the solder pads of the circuit board, and then use a mounting machine to mount surface mount components, such as resistors, capacitors, inductors, diodes, transistors or integrated circuits (IC), and then The circuit board and the surface mount components are sent into the soldering furnace together, and the solder paste is melted by reflow soldering. After the solder paste cools, the surface mount components can be combined with the pads of the circuit board to complete the assembly.

However, since the circuit board is sent into the welding furnace together with the surface-mounted components, the surface-mounted parts must have a certain degree of high temperature resistance. For the surface-mounted parts that are less resistant to high temperatures, the surface-mounted technology cannot be applied, and the traditional method must be used. More time-consuming wave soldering or less stable manual soldering.

The inventor then exhausted his brain and mind to study carefully, and then developed a welding method, in order to achieve the purpose of making most of the electronic components can be quickly and stably installed on the circuit board by automated technology.

For reaching the above object, the present invention provides a welding method, comprising the following steps: Step 1: Provide a circuit board having a top surface, a bottom surface, a plurality of conductive vias and a plurality of welding pads. The conductive through hole runs through the bottom surface and the top surface, and the welding pads are arranged on the top surface and respectively connected to the conductive through hole. Step 2: Provide an electronic component which has a main body and a plurality of leads extending from the main body. Step 3: Pass the plurality of leads of the electronic components through the conductive via holes from the bottom surface of the circuit board, and respectively protrude from the welding pads. Step 4: Form a plurality of soldering materials on the pads and the corresponding leads. Each welding material is filled between each conductive via hole and the corresponding lead pin. Step 5: Providing a heating device comprising a nozzle portion located above the top surface of the circuit board. Step 6: Execute the soldering process, send a high-temperature airflow from the nozzle to heat the soldering material, so that the soldering material reaches the soldering temperature, and then solder the leads to the conductive through holes, so that the electronic components are electrically connected to the circuit board.

In one embodiment, each solder material includes solder and flux mixed with each other.

In one embodiment, the soldering procedure includes an activation step and a soldering step. In the activation step, the nozzle part is separated from the circuit board by a first distance to send out high-temperature airflow. When the high-temperature airflow reaches the solder material, the temperature is reduced to an activated airflow to activate the flux, so that the flux can be removed from the guide pins, solder pads, and conductive vias. of oxides. The soldering step is to place the nozzle portion close to the circuit board to be separated from the circuit board by a second distance. The second distance is less than the first distance. The nozzle part sends out high-temperature airflow at a second distance from the circuit board. The high-temperature gas flow is used to make the solder reach the soldering temperature and melt, so that the solder solders the lead pins to the corresponding conductive vias.

In one embodiment, the first distance is between 40 cm and 45 cm, and the second distance is between 8 cm and 10 cm.

In one embodiment, the activating gas flow brings the solder material to an activation temperature between 110°C and 125°C.

In one embodiment, the high-temperature gas flow makes the welding material reach a welding temperature between 280°C and 310°C.

In one embodiment, the heating device moves vertically relative to the circuit board as a whole, so as to adjust the distance between the nozzle part and the circuit board.

In one embodiment, the electronic components and the circuit board are accommodated in the mold cavity. During the activation step, the mold cavity is not tightly sealed to the heating device, so that the outside air can enter the mold cavity, thereby cooling the high-temperature air flow for activation. Air flow; and in the welding step, the heating device and the mold cavity form a closed space to avoid the heat dissipation of the high-temperature air flow.

In one embodiment, the heating device further includes a flow divider. The flow divider is assembled in the nozzle part and has a plurality of flow dividers. The number of runners corresponds to the number of welding materials.

In one embodiment, in the vertical direction, each shunt overlaps each welding material.

Thereby, the soldering method of the present invention can concentrate the high-temperature airflow on the soldering material on the circuit board to reduce the impact on the electronic components mounted on the circuit board, so that most of the electronic components can be quickly And stably installed on the circuit board.

In order to fully understand the purpose, features and effects of the present invention, the present invention will be described in detail through the following specific embodiments and accompanying drawings, as follows:

Please refer to Fig. 1 to Fig. 6, the present invention provides a kind of welding method, comprises the following steps:

Step S101 : As shown in FIG. 1 and FIG. 2 , a circuit board 31 is provided which has a top surface 31 a , a bottom surface 31 b , a plurality of conductive vias H and a plurality of welding pads 310 . The conductive vias H penetrate the bottom surface 31b and the top surface 31a, and the pads 310 are disposed on the top surface 31a and connected to the conductive vias H respectively. The conductive via H can be formed by drilling a circuit board and then plating a metal layer, but it is not limited thereto. The circuit board 31 can be a flexible printed circuit (FPC), for being electrically connected to a control circuit board (not shown), but not limited thereto.

Step S102 : As shown in FIG. 1 and FIG. 3 , an electronic component 32 is provided which has a main body 320 and a plurality of leads 321 extending from the main body 320 . The main body 320 of the electronic component 32 can be a transistor, such as a laser diode (Laser Diode). After being entered into the main body 320, calculations or physical phenomena are generated and then transmitted.

Step S103 : as shown in FIG. 1 and FIG. 4 , pass the plurality of leads 321 of the electronic component 32 through the conductive through holes H from the bottom surface 31 b of the circuit board 31 , and respectively protrude from the pads 310 . When performing this step, the circuit board 31 can be fixed on a jig (not shown), and a mechanical arm (not shown) can hold and move the electronic component 32 . But it doesn't stop there. The ends of the plurality of guide pins 321 of the electronic component 32 may respectively have guiding slopes 322 with inclination angles ranging from 10° to 45°, so as to be guided and slide into the conductive via H when passing through the conductive via H, In order to reduce the difficulty of assembling the guide pin 321 into the conductive via H, and speed up the overall manufacturing process. After the guide pin 321 passes through the pad 310 , the part of the guide pin 321 having the guiding slope 322 can also be selected to be cut off.

Step S104 : as shown in FIG. 1 and FIG. 5 , form a plurality of solder materials 33 on the solder pad 310 and the corresponding guide pin 321 . Each solder material 33 is filled between each conductive via H and the corresponding lead pin 321 . The entire lead 321 may be covered by the solder material 33 , and a part of the solder material 33 flows into the conductive via H through a gap between the guide pin 321 and the conductive via H. Referring to FIG. The welding material can be formed by the glue dispenser 6, but is not limited thereto. The welding pad 310 can receive the welding material 33 and increase the area of electrical connection after welding.

Step S105 : as shown in FIG. 1 and FIG. 6 , provide the heating device 10 including the nozzle portion 220 located above the top surface 31 a of the circuit board 31 to perform a soldering process. The nozzle part 220 can send high-temperature airflow to heat the soldering material 33 , so that the soldering material 33 reaches the soldering temperature, and then solder the leads 321 to the conductive vias H, so that the electronic component 32 is electrically connected to the circuit board 31 .

Thereby, the soldering method of the present invention can concentrate the high-temperature gas flow on the soldering material on the circuit board to reduce the impact on the electronic components 32 mounted on the circuit board 31, so that most of the electronic components 32 can be automated The technology is quickly and stably installed on the circuit board 31.

As shown in FIG. 1 , FIG. 7 , FIG. 8 and FIG. 10 , in one embodiment, each solder material 33 may include solder and flux mixed with each other. The welding procedure of step S105 in FIG. 1 may include the activation step S1051 and the welding step S1052 shown in FIG. 7 . In the activation step S1051, the nozzle part 220 sends out the high-temperature airflow under the circuit board 31 at the first distance D1. The oxide (not shown) in the pad 310 and the conductive via H. Then carry out the welding step S1052, the welding step S1052 is to bring the nozzle part 220 close to the circuit board 31, so that the distance between the nozzle part 220 and the circuit board 31 is reduced from the first distance D1 to the second distance D2, and the nozzle part 220 is in contact with the circuit board 31. The high-temperature airflow sent by the circuit board 31 at the second distance D2 can melt the solder when reaching the solder material 33 , that is, reach the soldering temperature, so that the solder solders the lead 320 to the corresponding conductive via H. The first distance can be between 40 cm and 45 cm, preferably 43 cm. The second distance can be between 8 cm and 10 cm, preferably 9 cm. The activating gas flow can make the solder material 33 reach an activation temperature between 110°C and 125°C, preferably 119°C, to activate the flux, but not enough to melt the solder. The high-temperature gas flow can make the welding material 33 reach a welding temperature between 280°C and 310°C, preferably 295°C, to melt the solder. When the soldering process is performed, the assembly composed of the electronic component 32 and the circuit board 31 can be accommodated in the mold cavity 20. In the activation step S1051 in FIG. 10 and FIG. The outside air can enter the mold cavity 20, thereby cooling the high-temperature airflow into an activated airflow. In the welding step S1052 of FIG. 10 and FIG. 8 , the heating device 10 and the mold cavity 20 form a closed space S to prevent the heat energy of the high-temperature air from dissipating. The number of flow channels 232 of the flow distribution element 230 may correspond to the number of welding materials 33 , and each flow channel 232 may substantially overlap each welding material 33 , but it is not limited thereto. In other unillustrated embodiments, one runner 232 may also correspond to two welding materials 33 or other numbers of welding materials 33 . The flow divider 230 may further include an abutting portion 233 . The abutting portion 233 protrudes from the diverter body 230 and is adapted to abut against the circuit board 31 . When the abutting portion 233 abuts against the circuit board 31 , the distance between the nozzle portion 220 and the circuit board 31 is a second distance D2 . In addition, the flow channel 232 can be disposed around the abutting portion 233 .

As shown in FIGS. 7 to 9 , in an embodiment, the above-mentioned heating device 10 may include a heating body 200 , a nozzle part 220 and a flow divider 230 . The heating body 200 is adapted to generate high temperature air flow. The nozzle portion 220 is disposed at the bottom of the heating body 200 , and has a spray channel T1 communicating with the heating body 200 to circulate high-temperature air. The flow divider 230 includes a flow divider body 231 assembled in the spray channel T1 of the nozzle part 220 . The distribution body 231 has a plurality of distribution channels 232 . The splitter 230 can be detachably assembled on the nozzle part 220 by being screwed, but it is not limited thereto. In addition, according to different welding requirements, the nozzle part 220 can be assembled with different flow dividers 230 . The heating device 10 can be fixed on a jig (not shown in the figure), and equipped with a vertical sliding mechanism (not shown in the figure), so as to move vertically relative to the circuit board 31 as a whole, thereby adjusting the distance between the nozzle part 220 and the circuit board 31 , but not limited to this. The heating body 200 can be a cylindrical member with high thermal conductivity, and its material can be metal, ceramic, graphite or a composite material mixed with metal or alloy. The nozzle part 220 may be integrally extended to a pipe body at the bottom of the heating body 200 , but is not limited thereto. The outer side of the heating body 200 can be covered by the heat insulating shell 100 , and the outer side of the nozzle part 220 can be covered by the heat insulating member 300 , so as to prevent the heat energy of the heating device 10 from dissipating.

The present invention has been disclosed above with preferred embodiments, but those skilled in the art should understand that the embodiments are only used to describe the present invention, and should not be construed as limiting the scope of the present invention. It should be noted that all changes and substitutions equivalent to the embodiment should be included in the scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the scope of the patent application.

10: Heating device 100: insulated shell 20: Mold cavity 200: heating body 220: nozzle part 230: Diverter 231: Shunt body 232: Runner 233: abutting part 30: Electronic components 31: circuit board 310: welding pad 32: Electronic components 320: subject 321: guide foot 322: guide bevel 33: welding material 300: insulation 6: Glue dispenser D1: first distance D2: second distance H: Conductive via S: space T1: jet channel S101: step S102: step S103: step S104: step S105: step S1051: activation step S1052: Welding step

Fig. 1 is a schematic flow chart of a welding method according to a specific embodiment of the present invention. FIG. 2 shows a circuit board applicable to the soldering method of the embodiment of the present invention. FIG. 3 shows an electronic component applicable to the soldering method of the embodiment of the present invention. FIG. 4 is a schematic diagram showing an assembly of electronic components and a circuit board. FIG. 5 is a schematic diagram of forming a plurality of solder materials on a circuit board. FIG. 6 is a schematic cross-sectional view of a heating device that can be applied to the soldering method according to the embodiment of the present invention and is located above the electronic components and the circuit board. Fig. 7 is a first schematic cross-sectional view of the heating device heating the welding material. Fig. 8 is a second schematic cross-sectional view of the heating device heating the welding material. FIG. 9 is a schematic perspective view of a heating device applicable to a welding method according to a specific embodiment of the present invention. FIG. 10 is a schematic flowchart of step S105 in FIG. 1 .

S101: step

S102: step

S103: step

S104: step

S105: step

Claims (10)

A welding method comprising the steps of: Provide a circuit board, the circuit board has a top surface, a bottom surface, a plurality of conductive vias and a plurality of pads, the conductive vias are through the bottom surface and the top surface, the pads are arranged on the top surface and respectively connected to the conductive vias; An electronic component is provided, the electronic component has a main body and a plurality of guide pins extending from the main body; The plurality of guide pins of the electronic component respectively pass through the conductive via holes from the bottom surface of the circuit board, and respectively protrude from the solder pads; forming a plurality of soldering materials on the pads and the corresponding lead pins, each of the solder materials is filled between each conductive via hole and the corresponding lead pins; providing a heating device comprising a nozzle portion located above the top surface of the circuit board; and Executing a welding process, sending a high-temperature airflow from the nozzle to heat the soldering materials, so that the soldering materials reach the soldering temperature, and then soldering the leads to the conductive vias, so that the electronic The components are electrically connected to the circuit board. The soldering method according to claim 1, wherein each of the soldering materials includes solder and flux mixed with each other. The welding method as described in claim 2, wherein the welding procedure comprises: An activation step, the nozzle part sends out the high-temperature airflow under the circuit board at a first distance, and when the high-temperature airflow reaches the soldering materials, it cools down into an activated airflow to activate the flux, so that the flux can remove the oxides in the leads, the pads, and the conductive vias; and A soldering step, the nozzle part is close to the circuit board to be separated from the circuit board by a second distance, the second distance is smaller than the first distance, and the nozzle part is sent out of the circuit board by the second distance from the circuit board. The high-temperature gas flow is used to make the solder reach the soldering temperature and melt, so that the solder solders the leads to the corresponding conductive vias. The welding method according to claim 3, wherein the first distance is between 40 cm and 45 cm, and the second distance is between 8 cm and 10 cm. The welding method as claimed in claim 3, wherein the activated gas flow makes the welding material reach an activation temperature between 110°C and 125°C. The welding method as claimed in claim 3, wherein the high-temperature gas flow makes the welding material reach a welding temperature between 280°C and 310°C. The soldering method as claimed in claim 3, wherein the heating device moves vertically relative to the circuit board as a whole to adjust the distance between the nozzle portion and the circuit board. The soldering method as claimed in claim 3, wherein when the soldering process is performed, the electronic component and the circuit board are accommodated in a mold cavity, and in the activation step, the mold cavity is not tightly sealed to the heating device, so that outside air can enter the mold cavity, thereby cooling the high-temperature airflow into the activated airflow; and in the welding step, the heating device and the mold cavity form a closed space to avoid the high-temperature airflow Heat energy dissipates. The welding method as described in claim 1, wherein the heating device further includes a flow divider, the flow divider is assembled in the nozzle part and has a plurality of flow channels, and the number of the flow flow channels corresponds to the number of the welding materials . The welding method as claimed in claim 9, wherein in a vertical direction, each of the runners overlaps with each of the welding materials.

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