TWI768956B - Welding method - Google Patents

Abstract

The invention provides a welding method, comprising the following steps: providing a circuit board, an electronic component and a heating device, the circuit board has a plurality of conductive through holes and a plurality of solder pads connected to the conductive through holes, the electronic component has a plurality of lead pins, and the heating device includes a nozzle part; the plurality of lead pins of the electronic component are respectively passed through the conductive through holes from the bottom surface of the circuit board, and respectively protrude from the solder pads; a plurality of solder materials are formed on the solder pads and the corresponding lead pins, and each solder material is filled with between each conductive through hole and the corresponding lead pin; and send out high-temperature airflow from the nozzle part to heat the soldering material, so that the soldering material reaches the soldering temperature, and then solder the lead pin to the conductive through hole respectively, so as to make the electronic components Electrically connected to the circuit board.

Description

Welding method

The present invention provides a welding method, especially a welding method in which the welding material is heated by a high-temperature air flow.

Surface Mount Technology is a soldering technology that combines electronic components on circuit boards. Specifically, surface mount technology prints solder paste on the pads of a circuit board, and then uses a mounter to mount surface-attached components, such as resistors, capacitors, inductors, diodes, transistors, or integrated circuits (ICs), and then The circuit board and the surface-attached components are sent into the soldering furnace, and the solder paste is melted by reflow soldering. After the solder paste is cooled, the surface-attached parts can be combined with the pads of the circuit board to complete the assembly.

However, since the circuit board is sent into the soldering furnace together with the surface-attached components, the surface-attached parts must have a certain high temperature resistance. For the surface-attached parts that are less resistant to high temperature, the surface-attached technology cannot be applied, and traditional methods must be used. Time-consuming wave soldering or less stable manual soldering.

The inventor then exhausted his mind and researched, and then developed a soldering method, in order to achieve the purpose that most of the electronic components can be quickly and stably mounted on the circuit board by automated technology.

For the purpose of disclosure, 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 solder pads. The conductive vias penetrate through the bottom surface and the top surface, and the pads are disposed on the top surface and are respectively connected to the conductive vias.

Step 2: Provide an electronic component having a main body and a plurality of lead pins extending from the main body.

Step 3: Pass the plurality of lead pins of the electronic component through the conductive through holes respectively from the bottom surface of the circuit board, and protrude from the solder pads respectively.

Step 4: forming a plurality of solder materials on the solder pads and the corresponding lead pins. Each solder material is filled between each conductive through hole and the corresponding lead pin.

Step 5: Provide a heating device including 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 lead pins to the conductive through holes, so as to electrically connect the electronic components to the circuit board.

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

In one embodiment, the welding procedure includes an activation step and a welding step. In the activation step, the nozzle part sends out a high-temperature airflow under the circuit board at a first distance, and when the high-temperature airflow reaches the solder material, it cools down to become an activated airflow, so as to activate the flux and remove the flux from the guide pins, solder pads and conductive through holes. of oxides. The soldering step is to bring the nozzle portion 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. The nozzle part sends out a high-temperature airflow at a second distance from the circuit board. The high-temperature airflow is used to make the solder reach the soldering temperature and melt, so that the solder can solder the lead pins to the corresponding conductive through holes.

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 activation air flow brings the welding material to an activation temperature between 110 degrees Celsius and 125 degrees Celsius.

In one embodiment, the high temperature airflow brings the welding material to a welding temperature between 280 degrees Celsius and 310 degrees Celsius.

In one embodiment, the heating device is vertically moved relative to the circuit board as a whole to adjust the distance between the nozzle portion and the circuit board.

In one embodiment, the electronic components and the circuit board are accommodated in the mold cavity, and in the activation step, the mold cavity is not close to the heating device, so that the outside air can enter the mold cavity, thereby cooling the high-temperature airflow to activate the mold cavity. In the welding step, the heating device and the mold cavity form a closed space to prevent the heat energy of the high-temperature airflow from dissipating.

In one embodiment, the heating device further includes a diverter. The shunt piece is assembled in the nozzle part and has a plurality of shunt channels. The number of runners corresponds to the amount of welding material.

In one embodiment, in the vertical direction, each runner 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, so as to reduce the influence on the electronic components mounted on the circuit board, so that most of the electronic components can be quickly processed by automated technology. and stably mounted on the circuit board.

10: Heating device

100: Insulated shell

20: Mold cavity

200: Heating the main body

220: Nozzle part

230: Diverter

231: Shunt Ontology

232: shunt channel

233: Abutment

30: Electronic Components

31: circuit board

310: Solder pad

32: Electronic Components

320: Subject

321: Guide feet

322: Guide Bevel

33: Welding materials

300: Thermal insulation

6: Dispenser

D1: first distance

D2: Second distance

H: conductive via

S: space

T1: Jet runner

S101: Steps

S102: Steps

S103: Steps

S104: Steps

S105: Steps

S1051: Activation step

S1052: Welding step

FIG. 1 is a schematic flowchart of a welding method according to a specific embodiment of the present invention.

FIG. 2 is a circuit board showing a soldering method applicable to an embodiment of the present invention.

FIG. 3 shows an electronic component applicable to a soldering method according to an embodiment of the present invention.

FIG. 4 is a schematic diagram showing a combination of electronic components and circuit boards.

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 an embodiment of the present invention located above the electronic components and the circuit board.

FIG. 7 is a schematic cross-sectional view 1 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 the welding method according to an embodiment of the present invention.

FIG. 10 is a schematic flowchart of step S105 in FIG. 1 .

In order to fully understand the purpose, features and effects of the present invention, the present invention is described in detail by the following specific embodiments and the accompanying drawings. The description is as follows: The invention provides a method for welding, comprising the following steps:

Step S101 : as shown in FIG. 1 and FIG. 2 , provide a circuit board 31 having a top surface 31 a , a bottom surface 31 b , a plurality of conductive vias H and a plurality of solder pads 310 . The conductive via H penetrates through the bottom surface 31b and the top surface 31a, and the bonding pads 310 are disposed on the top surface 31a and connected to the conductive via H respectively. The conductive through holes H can be formed by means of electroplating a metal layer after drilling the circuit board, but not limited to this. The circuit board 31 may be a flexible printed circuit (FPC), which is used for electrical connection to a control circuit board (not shown), but is not limited thereto.

Step S102 : As shown in FIG. 1 and FIG. 3 , provide the electronic component 32 having a main body 320 and a plurality of lead pins 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, and the lead 320 is electrically connected to the main body 320 . After entering the main body 320, perform operations or generate physical phenomena and then transfer them out.

Step S103 : As shown in FIG. 1 and FIG. 4 , the plurality of lead pins 321 of the electronic component 32 are respectively passed through the conductive through holes H from the bottom surface 31 b of the circuit board 31 and protrude from the bonding pads 310 respectively. During this step, the circuit board 31 can be fixed on a fixture (not shown), and the electronic component 32 can be held and moved by a mechanical arm (not shown). But it doesn't stop there. The ends of the plurality of lead pins 321 of the electronic component 32 may respectively have guiding slopes 322 with an inclination angle between 10 degrees and 45 degrees, so as to be guided to slide into the conductive through holes H when passing through the conductive through holes H, In order to reduce the difficulty of assembling the lead pins 321 into the conductive vias H, and to speed up the overall process. After the guide pins 321 pass through the solder pads 310 , the part of the guide pins 321 with the guiding slopes 322 can be optionally cut off.

Step S104 : As shown in FIG. 1 and FIG. 5 , a plurality of soldering materials 33 are formed on the soldering pads 310 and the corresponding lead pins 321 . Each solder material 33 is filled between each conductive through hole H and the corresponding lead pin 321 . The entirety of the lead pins 321 may be covered by the solder material 33 , and a part of the solder material 33 flows into the conductive via holes H through the gaps between the lead pins 321 and the conductive via holes H. As shown in FIG. The welding material may be formed by the glue dispenser 6, but is not limited thereto. The soldering pads 310 can receive the soldering material 33 and increase the area of the electrical connection after soldering.

Step S105 : As shown in FIG. 1 and FIG. 6 , provide the heating device 10 including the nozzle part 220 located above the top surface 31 a of the circuit board 31 to perform the soldering process. The nozzle portion 220 can send out high temperature airflow to heat the soldering material 33 , so that the soldering material 33 reaches the soldering temperature, and then the lead pins 321 are soldered to the conductive through holes H respectively, so that the electronic components 32 are electrically connected to the circuit board 31 .

Therefore, the soldering method of the present invention can concentrate the high-temperature airflow on the soldering material on the circuit board, so as to reduce the influence on the electronic components 32 mounted on the circuit board 31, so that most of the electronic components 32 can be automatically The technology is fast and stable on the circuit board 31.

As shown in FIGS. 1 , 7 , 8 and 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 The activation step S1051 and the welding step S1052 are performed. In the activation step S1051 , the nozzle part 220 sends out a high-temperature airflow under the circuit board 31 separated by a first distance D1, and when the high-temperature airflow reaches the soldering material 33, the temperature is lowered to become an activated airflow, so as to activate the flux, so that the flux removes the guide pins 321 and the solder. The pad 310 and the oxide (not shown) in the conductive via H. Next, the welding step S1052 is performed. The welding step S1052 is to move 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 close to the circuit board 31. When the circuit board 31 is separated by a second distance, the high-temperature airflow sent from D2 can melt the solder when it reaches the soldering material 33 , that is, it reaches the soldering temperature, so that the solder can solder the lead pins 320 to the corresponding conductive through holes H. The first distance may be between 40 cm and 45 cm, preferably 43 cm. The second distance may be between 8 cm and 10 cm, preferably 9 cm. The activation air flow can make the solder material 33 reach an activation temperature between 110 degrees Celsius and 125 degrees Celsius, preferably 119 degrees Celsius, to activate the flux, but not enough to melt the solder. The high-temperature airflow can make the soldering material 33 reach a soldering temperature between 280 degrees Celsius and 310 degrees Celsius, preferably 295 degrees Celsius, to melt the solder. When the soldering process is performed, the assembly formed by the electronic components 32 and the circuit board 31 can be accommodated in the mold cavity 20. In the activation step S1051 in FIG. 10 and FIG. 7, the mold cavity 20 is not in close contact with the heating device 10, So that the outside air can enter into the cavity 20, thereby cooling the high-temperature airflow into an activated airflow. In the welding step S1052 in FIGS. 10 and 8 , the heating device 10 and the mold cavity 20 form a closed space S to prevent the heat energy of the high-temperature airflow from dissipating. The number of the shunt channels 232 of the shunt member 230 may correspond to the number of the welding materials 33 , and each of the shunt channels 232 may substantially overlap each of the welding materials 33 , but is not limited thereto. In other not-shown embodiments, one runner 232 may also correspond to two welding materials 33 or other quantities of welding materials 33 . The diverting member 230 may further include an abutting portion 233 . The abutting portion 233 protrudes from the shunt body 230 and is suitable for abutting 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 the second distance D2 . In addition, the branch channel 232 may be disposed around the abutting portion 233 .

As shown in FIG. 7 to FIG. 9 , in one embodiment, the above-mentioned heating device 10 may include a heating body 200 , a nozzle part 220 and a diverter 230 . The heating body 200 is adapted to generate high temperature airflow. The nozzle part 220 is disposed at the bottom of the heating body 200 , and the nozzle part 220 has an air jet flow channel T1 which is communicated with the heating body 200 to flow high-temperature airflow. The diverter member 230 includes a diverter body 231 assembled in the jet flow channel T1 of the nozzle portion 220 . The shunt body 231 has a plurality of shunt channels 232 . The diverting member 230 can be detachably assembled on the nozzle portion 220 by screwing, but is not limited to this. In addition, according to different welding requirements, the nozzle portion 220 can be assembled with different diverting members 230 . The heating device 10 can be fixed on a fixture (not shown in the figure), and is equipped with a vertical sliding mechanism (not shown in the figure) to move vertically relative to the circuit board 31 as a whole, so as to adjust 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 doped with metals or alloys. The nozzle part 220 may be a pipe body extending from the bottom of the heating body 200 as a whole, but is not limited thereto. The outer side of the heating body 200 may be covered by the heat insulating casing 100 , and the outer side of the nozzle portion 220 may 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 this embodiment should be considered to be included within the scope of the present invention. Therefore, the protection scope of the present invention should be defined by the scope of the patent application.

S101: Steps

S102: Steps

S103: Steps

S104: Steps

S105: Steps

Claims (8)

A welding method, comprising the following steps: providing a circuit board, the circuit board has a top surface, a bottom surface, a plurality of conductive through holes and a plurality of solder pads, the conductive through holes penetrate the bottom surface and the top surface, the solder The pads are arranged on the top surface and are respectively connected to the conductive through holes; an electronic component is provided, the electronic component has a main body and a plurality of lead pins extending from the main body; the plurality of lead pins of the electronic component are removed from the circuit board The bottom surfaces respectively pass through the conductive through holes and protrude from the solder pads respectively; a plurality of soldering materials are formed on the solder pads and the corresponding lead pins, and the soldering materials are filled in the conductive through holes and the corresponding lead pins. Between the corresponding lead pins, each of the soldering materials includes solder and flux mixed with each other; a heating device is provided, the heating device includes a nozzle part located above the top surface of the circuit board; and a soldering process is performed, A high-temperature airflow is sent from the nozzle portion to heat the soldering materials, so that the soldering materials reach the soldering temperature, and then the lead pins are respectively soldered to the conductive through holes, so that the electronic component is electrically connected to the The circuit board; wherein the welding process includes: an activation step, the nozzle part is separated from the circuit board by a first distance to send out the high-temperature airflow, and the high-temperature airflow is cooled to an activated gas when it reaches the soldering materials flow to activate the flux so that the flux removes oxides in the leads, the pads and the conductive vias; and a soldering step of approaching the nozzle portion to the circuit board to connect with the circuit board The circuit boards are separated by a second distance, and the second distance is smaller than the first distance, and the nozzle part sends out the high-temperature airflow when separated from the circuit board by the second distance, and the high-temperature airflow is used to make the solder reach the soldering temperature. melting, so that the solder solders the lead pins to the corresponding conductive through holes. The welding method of claim 1, 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 of claim 1 , wherein the activated air flow enables the welding material to reach an activation temperature between 110 degrees Celsius and 125 degrees Celsius. The welding method as claimed in claim 1, wherein the high temperature airflow makes the welding material reach a welding temperature between 280 degrees Celsius and 310 degrees Celsius. The welding method of claim 1, wherein the heating device is vertically moved relative to the circuit board as a whole to adjust the distance between the nozzle portion and the circuit board. The soldering method according to claim 1, 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 in close contact with the heating device, So that the outside air can enter the cavity, thereby cooling the high-temperature airflow into the activated airflow; and in the welding step, the heating device and the cavity form a closed space to avoid the high-temperature airflow. Thermal energy dissipates. The welding method as claimed in claim 1, wherein the heating device further comprises a shunt member, the shunt member is assembled in the nozzle portion and has a plurality of shunt channels, and the number of the shunt channels corresponds to the number of the welding materials . The welding method of claim 7, wherein each of the runners overlaps each of the welding materials in a vertical direction.

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