JP7459671B2 - Laser soldering method - Google Patents

Description

The present invention relates to a laser soldering method.

2. Description of the Related Art Conventionally, when mounting electronic components on a board, a laser soldering method has been adopted in which soldering is performed by irradiating a portion of the board to be soldered with laser light from a laser head (see, for example, Japanese Patent Application Laid-Open No. 2003-233634).
Specifically, for example, soldering is performed by melting the solder with the heat of a laser beam to form a soldering portion for soldering a land around a through hole in a substrate to a terminal of an electronic component. This laser soldering method has the advantages of being able to perform non-contact soldering even in extremely small places that cannot be handled by a method using a soldering iron, and of being able to reduce the load on the substrate while suppressing the generation of solder balls.

Japanese Patent Application Publication No. 2011-29659

Conventional laser soldering methods can cause problems such as burning of the board by the laser light, poor soldering due to heat dissipation, etc. Therefore, it is conceivable to set or switch the soldering conditions such as the laser output for each soldered portion in accordance with the land diameter, etc. on the board.
However, in an actual manufacturing process, for example, soldering is performed at a dozen or so locations on a single board, and if the soldering conditions corresponding to each location are to be set for a large number of boards, it would take a lot of time just to switch the conditions.

The present invention was made in consideration of the above circumstances, and its purpose is to provide a laser soldering method that can suppress the increase in time that accompanies setting soldering conditions corresponding to the soldered portion and improve the reliability of soldering.

According to the invention described in claim 1, it is possible to set soldering conditions corresponding to each soldering part in the setting step, and the setting of the soldering conditions and the relative movement of the laser head (10) can be controlled. This can be done in parallel, and the time can be reduced compared to setting the soldering conditions after relative movement of the laser head.
In addition, since the start condition includes the completion of the relative movement of the laser head to the position where the soldering is to be performed, the soldering process can be performed at an appropriate timing without causing problems such as irradiating the laser beam while the laser head is moving relative to the position. connection can be started, and a highly reliable connection can be made overall.

FIG. 1 is a schematic diagram showing a schematic configuration of an entire apparatus for explaining a laser soldering method according to an embodiment; A diagram showing the process flow in cooperation with the main control device, the supply control device, and the laser control device in this equipment. A timing chart showing the settings of soldering conditions and the timing of relative movement of the laser head Time chart to explain the operation timing when starting soldering in the conventional configuration

An embodiment of the present disclosure will be described below with reference to the drawings. A laser soldering apparatus 1 schematically shown in FIG. 1 includes a laser head 10 that irradiates laser light for soldering, and a base 11 on which a board 2 to be soldered is set.
The board 2 is a rectangular plate-shaped circuit board on which an electronic component 3 is mounted, and has a plurality of through holes 4 penetrating in the board thickness direction and a land 5 provided around each of the through holes 4. The terminals 3a of the electronic component 3 inserted into the through holes 4 of the board 2 and the lands 5 are soldered parts that are electrically connected via solder.

Although not shown in the figure, one board 2 may have, for example, 12 soldered portions, and for convenience, FIG. 1 shows only one representative soldered portion. In the following, the tip side of the terminal 3a of the electronic component 3 in the soldered portion in the figure is referred to as the upper side, and the opposite side is referred to as the lower side. The thickness direction of the board 2, which is the up-down direction in FIG. 1, is referred to as the Z direction. Furthermore, the left-right direction in the figure along one side of the periphery of the board 2 is referred to as the X direction, and the direction perpendicular to the paper surface of the figure is referred to as the Y direction.

In the laser soldering apparatus 1, the laser head 10 can be moved relative to the substrate 2 in the X direction, Y direction, and Z direction using, for example, a robot arm (not shown) as a moving means. In this case, the laser head 10 is provided at the tip of the multi-jointed robot arm, and by driving each arm, the laser head 10 is relatively moved so that the irradiation area of the laser beam is aligned with the terminal 3a and the land 5 to be soldered. (Refer to the optical axis O of the laser beam). In the step of moving the laser head 10, the setting surface 11a of the base 11, which is the setting part for the substrate 2, may be moved together with the substrate 2 as a so-called XY table. Hereinafter, the "relative movement" of the laser head 10 will also be simply referred to as "movement."

The solder thread indicated by reference numeral 12 in FIG. 1 is solder thread 12, the supply source of which is a solder supply device 13. The solder supply device 13 includes a solder guide 13a provided at the tip side of the robot arm. As a result, the solder supply device 13 is configured to feed the solder thread 12 from a predetermined direction toward the soldering portion while guiding it with the solder guide 13a. Note that for ease of explanation, the solder guide 13a and the laser head 10 are shown in FIG. 1 in positions spaced apart from each other, but the solder guide 13a is moved together with the laser head 10 by the robot arm.

The laser soldering apparatus 1 is equipped with peripheral equipment such as a loading belt and an unloading belt for loading and unloading the board 2, and the entire equipment including the peripheral equipment is connected to the equipment 15 or the main unit. It is called equipment 15. In this equipment 15, in addition to the carrying-in process of carrying the substrate 2 to the set surface 11a via the carrying-in belt and the carrying-out process of carrying out the substrate 2 out of the equipment via the carrying-out belt, a moving process of the laser head 10, A series of steps including a setting step for setting soldering conditions, which will be described later, are automatically performed (see FIG. 2, which will be described later).

Here, the main control device 16, which is responsible for controlling the entire equipment 15 shown in FIG. 1, is mainly composed of a microcomputer and has a storage unit consisting of ROM, RAM, etc. The main control device 16 is connected to various actuators in the robot arm, etc., and an operation input unit (not shown), as well as to a laser control device 17, a supply control device 18, etc. The storage unit of the main control device 16 stores a control program, as well as coordinate data corresponding to each soldering portion on the board 2, soldering conditions associated with the soldering portions, etc. The main control device 16 communicates with the laser control device 17 and the supply control device 18, and executes the processing related to the series of steps in cooperation with each of the control devices 17, 18.

The coordinate data specifies, for example, the laser irradiation position to which the laser head 10 moves in the movement process using X coordinates, Y coordinates, and Z coordinates, and includes the offset from the standby position of the laser head 10 to the laser irradiation position. It is defined as a coordinate or an offset coordinate corresponding to the position of each soldering part from a reference position on the board 2. Specifically, the coordinate data is stored for each type of board 2, and for example, if there are 12 soldering parts on one board 2, the coordinate data is stored for each type of board 2, such as a first soldering part, a second soldering part, ...It shall be stored together with order data for sequentially moving the laser head 10 in correspondence with each position of the twelfth soldering part. Thereby, the main controller 16 controls various actuators in the movement process based on the coordinate data, and sequentially moves the laser head 10 to a position where soldering is performed, that is, a laser irradiation position.

The laser control device 17 controls an oscillation section (not shown) that generates laser light, and is mainly composed of a microcomputer having a storage section. Laser light output from the oscillation section is irradiated from the laser head 10 toward the substrate 2 along the optical axis O. Prior to this laser light irradiation, the laser control device 17 communicates with the main control device 16 regarding soldering conditions, and sets control parameters related to laser light irradiation.
The control parameters related to laser light irradiation include, for example, the laser output (W) and the irradiation time (Sec) of the laser light. Further, the control parameters are stored in association with the offset coordinates of each soldering part or the order data, depending on the type of the board 2.

The supply control device 18 controls the solder guide 13a and the solder supply device 13, and is mainly composed of a microcomputer having a storage unit. Prior to the irradiation of the laser light, the supply control device 18 communicates with the main control device 16 regarding the soldering conditions, and sets control parameters related to the supply of the solder material.
The control parameters relating to the supply of the solder material include, for example, the solder supply angle θ between the solder wire 12 and the surface of the board 2 (the top surface in FIG. 1), the solder supply direction around the land 5 as viewed from the top surface side, and the supply speed of the solder wire 12. Furthermore, the control parameters are stored in association with offset coordinates or sequence data for each soldering portion according to the type of board 2.

The soldering conditions may include additional conditions such as setting the size of the irradiation area or the diameter of the laser light so that the laser light does not extend beyond the land 5. In addition, the main control device 16, the laser control device 17, and the supply control device 18 each have an operation input unit such as a touch panel (not shown), which allows for advance teaching or input of settings related to the soldering conditions.

Now, the soldering conditions are set for each type of board 2 according to the shape and dimensions of the land 5, taking into account the heat dissipation and other factors mentioned in the "Problem to be solved" section, thereby improving the quality and reliability of the soldering.

However, if the soldering conditions include various parameters and the setting and switching of the parameters is performed for each soldered portion, it will take a lot of time in the manufacturing process, which will lead to a decrease in the production efficiency of the board 2. Specifically, as shown in the time chart of FIG. 4, it is assumed that when soldering is started, the laser head is moved from the standby position to the laser irradiation position, and then the laser start is instructed to set the soldering conditions. In this case, as shown by T1 and T2 in the figure, the solder supply control device and the laser control device require times T1 and T2 to receive the soldering conditions from the main control device of the equipment and switch to the corresponding control parameters, respectively. Therefore, even if the laser light irradiation is started immediately after the control parameters are set, it will take time (T1 + T2 + T3) from the laser start instruction to the completion of soldering, which will be a factor in reducing the production efficiency of the board 2.

Therefore, in this equipment 15, as shown as "condition switching" in FIGS. 2 and 3, while setting appropriate soldering conditions corresponding to each soldering part, we are able to prevent the accompanying decrease in production efficiency. It is intended to be suppressed. This configuration will be described in detail with reference to FIGS. 2 and 3. Here, for convenience of explanation, FIG. 2 shows the process flow in the case where one soldering part exists on one board 2, and in the process of moving the laser head 10, the solder material is supplied. The relevant control parameters shall be switched. In addition, A1 to A11, B1 to B5, and C1 to C3 in FIG. 2 represent each step, and the carrying-in means including the carrying-in belt is the "carrying-in device", and the carrying-out means including the carrying-out belt is the "carrying-out device". '' to simplify the explanation.

That is, first, when the main control device 16 of the equipment 15 starts the process shown in FIG. 2, in the carry-in process, the board 2 is loaded into the machine by the carry-in device and set on the setting surface 11a (A1). At this time, on the board 2, the terminals 3a of the electronic component 3 inserted into the through-holes 4 and arranged to protrude as shown in FIG. 1 and the lands 5 are used as soldering parts.

Next, the main control device 16 reads the coordinate data and soldering conditions associated with the board 2, and controls the robot arm based on the coordinate data to move the laser head 10 from its original standby position to the laser irradiation position corresponding to the soldered portion (A2, A3).

Then, the main control device 16 executes processing to set control parameters related to the supply of solder material during the movement steps A2 and A3 (A5-A8). In this case, the main control device 16 checks the soldering conditions for the board 2 to be set this time, and if it determines that the settings need to be changed (A5), it sets the soldering conditions (A6) and outputs them to the supply control device 18 (A7).

As a result, the supply control device 18 receives information related to switching the soldering conditions (B1), and performs a setting step for switching to the soldering conditions (B2). In the setting step, at least one of the solder supply angle θ, the solder supply direction, the supply speed of the solder wire 12, etc. as control parameters related to the supply of solder material is switched and set. In this way, when the condition switching is completed, the supply control device 18 outputs a condition switching completion signal indicating this to the main control device 16 on the equipment 15 side (B3).

When the main controller 16 receives the condition switching completion signal output from the supply controller 18 (A8) and determines that the movement of the laser head 10 to the laser irradiation position is completed (A4), it stops irradiating the laser beam. In order to start, the control parameters related to the laser control device 17 are outputted, and the supply control device 18 is instructed to supply the thread solder 12 in accordance with the laser beam irradiation (A9).

As a result, when the laser control device 17 receives an instruction for control parameters related to laser beam irradiation, a setting step of switching to the control parameters is performed (C1). In this setting step, at least one of the control parameters related to laser light irradiation, such as the laser output and irradiation time, is switched and set.

When the laser control device 17 finishes setting the soldering conditions, it is assumed that the soldering start conditions are satisfied, and the laser control device 17 causes the oscillation section to generate a laser beam and irradiate it from the laser head 10 (C2). In this soldering process, the laser beam is irradiated with a set output for a predetermined period of time with both the land 5 and the terminal 3a in the soldering part as the irradiation area, and the solder thread 12 is set while being guided by the solder guide 13a. It is delivered to the irradiation area at a predetermined speed from the supply angle θ or supply direction (B4), and soldering is performed.

In this way, when the laser control device 17 completes the laser beam irradiation, it outputs the irradiation completion signal to the main control device 16 (C3), and when the supply control device 18 completes the supply of the solder thread 12, the supply completion signal is outputted to the main control device 16 (C3). is output to the main controller 16 (B5).
Upon receiving the irradiation completion signal from the laser control device 17 and the supply completion signal from the supply control device 18 (A10), the main control device 16 moves the laser head 10 to the original position using the robot arm (A11). , the substrate 2 is carried out of the machine from the set surface 11a by the carry-out device (A12). In this way, when the main controller 16 completes the processing in which A1 to A12, B1 to B5, and C1 to C3 are one cycle (A13), the main controller 16 returns to "Start" in FIG. can also be processed continuously.

The above-mentioned A2 to A4 movement steps may be configured so that both B2 and C1 conditions are switched. This specific configuration will be described with reference to the time chart in FIG. 3. Here, t1 to t4 in FIG. 3 represent the time points from the start of movement of the laser head 10 to the completion of movement, t2 to t3 represent the time required for setting the control parameters in the supply control device 18 and the control parameters in the laser control device 17, and t4 to t5 represent the time required for soldering.

That is, the main control device 16 starts the process with the loading step, sets the inserted board 2 on the set surface 11a (A1 in FIG. 2), and then at the start of the subsequent movement step, that is, at time t1 in FIG. 3, moves the laser head 10 from the original position to the laser irradiation position based on the coordinate data associated with the board 2 (A2, A3).

During this movement process, the main control device 16 outputs control parameters related to the supply of solder material to the supply control device 18 (t2 in FIG. 3) and outputs control parameters related to the irradiation of laser light to the laser control device 17 (t2 in FIG. 3) in order to perform the soldering condition setting process (A5-A9, B1-B3, C1) in parallel. This allows the supply control device 18 to perform a setting process of switching to the control parameters received during the movement process, and the laser control device 17 to perform a setting process of switching to the control parameters received.

Thereafter, the supply control device 18 outputs a condition switching completion signal to the main control device 16 upon completion of the setting process, and the laser control device 17 outputs a condition switching completion signal to the main control device 16 upon completion of the setting process. Output.

Here, the main control device 16 determines that the condition switching is completed at time t3 when the condition switching completion signal is received from both the supply control device 18 and the laser control device 17. Further, as illustrated in FIG. 3, the main controller 16 assumes that the start condition is satisfied at the time t4, which is after t3 and when the movement of the laser head 10 to the laser irradiation position is completed. In other words, the laser control unit 17 is instructed to start laser beam irradiation, and the supply control unit 18 is instructed to start supplying the solder wire 12, thereby completing the soldering process.

Thereafter, at time t5 when the soldering process is completed and the irradiation completion signal from the laser control device 17 and the supply completion signal from the supply control device 18 are received, the main control device 16 switches the laser head 10 to the original state. At the same time, the substrate 2 is carried out of the machine from the set surface 11a, and this process is completed.

In addition, in FIG. 2 and FIG. 3, the case where one soldering part exists on one board 2 is explained as an example, but the same laser Processing can be performed using a soldering method. Specifically, for example, even if the first soldering section, the second soldering section, ... the twelfth soldering section exist on one board 2, and the soldering conditions are different for each soldering section, the soldering conditions shown in Fig. The processes A1 to A10, B1 to B5, and C1 to C3 in FIG. 2 or the processes explained in the time chart t1 to t5 in FIG. 3 can be executed for each soldering part according to the order data.

As explained above, the laser soldering method of the present embodiment includes a movement process in which the laser head 10 is moved relative to the substrate 2 to a position where soldering is to be performed, and an individual solder to be moved in the movement process. A setting process for setting the soldering conditions for laser beam soldering, which are soldering conditions corresponding to the soldering part, and starting soldering when the soldering conditions corresponding to the soldering part are set. Assuming that the start conditions have been met, a soldering process is provided in which soldering is performed by irradiating a laser beam, and by setting the soldering conditions during the moving process, the moving process and the setting process are performed in parallel. The start condition includes that the relative movement to the soldering position is completed.

This allows the setting process to set soldering conditions corresponding to each soldering portion, and the setting of the soldering conditions and the relative movement of the laser head 10 can be performed in parallel, thereby reducing the time required compared to setting the soldering conditions after the relative movement of the laser head 10.
Furthermore, since the start condition includes completion of the relative movement of the laser head 10 to the position where soldering is to be performed, soldering can be started at an appropriate timing without causing a problem such as irradiating laser light during the relative movement of the laser head 10, and an overall highly reliable connection can be made.

This equipment 15 is configured to irradiate the laser beam and start soldering when the relative movement of the laser head 10 to the soldering position is completed and the soldering conditions have been set. There is. Therefore, regardless of the length of the set process time from t2 to t3 with respect to the moving process time from t1 to t4 in FIG. 3, for example, the time can be shortened as much as possible.

The soldering conditions include control parameters related to the irradiation of the laser light and control parameters related to the supply of the solder material to the soldering portion. Therefore, each control parameter can be set during the movement process, making it possible to shorten the times T1 and T2 described in FIG. 4.

In addition, when multiple soldering conditions are set to correspond to multiple soldering portions on one board 2, it is possible to significantly reduce the time required for the manufacturing process of that board 2, thereby improving production efficiency.

Although the present disclosure has been described based on examples (embodiments), it is understood that the present disclosure is not limited to the examples or structures. The present disclosure also encompasses various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and concept of the present disclosure.
For example, the number of soldered portions on the substrate 2 and the soldering conditions are not limited to the numbers and control parameters described above, and can be changed as appropriate.

In the drawing, 1 indicates a laser soldering device, 2 indicates a board, 3a indicates a terminal (soldering part), 5 indicates a land (soldering part), and 10 indicates a laser head.

Claims (4)

A laser soldering method for performing soldering by irradiating a soldering portion of a substrate (2) to be soldered with a laser light from a laser head (10), comprising the steps of:
a moving step of moving the laser head relative to the board to a position where soldering is performed;
a setting step of setting at least one of a control parameter related to the irradiation of the laser light at the destination and a control parameter related to the supply of the solder material to the soldering portion as a soldering condition corresponding to each of the soldering portions to be moved in the moving step, the control parameter being related to the application of the laser light at the destination and a control parameter related to the supply of the solder material to the soldering portion;
a soldering process of irradiating the laser light to perform soldering when the soldering conditions corresponding to the soldered portion are set, assuming that a start condition for starting soldering is met;
A laser soldering method in which the moving process and the setting process are performed in parallel by setting the soldering conditions corresponding to the soldering portion of the destination during the moving process, and the start condition includes completion of the relative movement to the position where the soldering is performed. 2. The laser soldering according to claim 1, wherein the laser beam is irradiated to start soldering when the relative movement of the laser head to the soldering position is completed and the setting of the soldering conditions is completed. How to attach. The laser soldering method according to claim 1 or 2, wherein the soldering conditions include control parameters related to the irradiation of the laser light and control parameters related to the supply of the solder material to the soldering portion. 4. The laser soldering method according to claim 1, wherein a plurality of said soldering conditions are set corresponding to a plurality of said soldering parts on one said board.

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