Soldering device and non-transitory computer-readable medium

Abstract

A soldering device (1) comprises: a solder feeder (26) that supplies solder (27) to a soldering iron (24); a drive unit (30) that moves the soldering iron (24); and a processing unit (51) that causes the solder feeder (26) to supply a first amount of solder to a tip (24A) of the soldering iron (24), causes the drive unit (30) to move the tip (24A) of the soldering iron (24) on which the first amount of solder has been melted to a position where the tip (24A) of the soldering iron (24) comes into contact with a soldering site, and causes the solder feeder (26) to supply, at a preset supply start timing, a second amount of solder to the tip (24A) of the soldering iron (24) that has come into contact with the soldering site. The processing unit (51) determines whether or not a heat bridge has been formed due to the first amount of solder being wetted at the position where the tip (24A) of the soldering iron (24) has come into contact with the soldering site, and adjusts the supply start timing so that the second amount of solder is supplied after the processing unit (51) has determined that the heat bridge has been formed.

Description

SOLDERING APPARATUS AND NON-TRANSITORY COMPUTER-READABLE MEDIUM

[0001] The present disclosure relates to a soldering apparatus, and also to a non-transitory computer-readable medium storing a computer program executable by a processing unit of a control device installed in the soldering apparatus.

[0002] Japanese Patent Application Laid-Open No. 2006-103663 discloses a soldering machine that automatically performs soldering. The soldering machine moves the tip of a heating tool to the position of a part to be soldered, such as a land or lead, and delivers solder to the tip of the heating tool, melting the solder to perform the soldering. When teaching the machine, an operator operates an input unit to input soldering conditions such as the timing of soldering and the amount of solder supplied.

[0003] Japanese Patent No. 6764393

[0004] When transferring heat from a heating tool to a soldered part, the tip of the heating tool and the part to be soldered are rigid bodies, resulting in high thermal resistance when these bodies make point or line contact. Therefore, solder is supplied to the part to be soldered in two separate applications. The first solder application (hereinafter referred to as the primary solder) forms a bridge (hereinafter referred to as a heat bridge) with the part to be soldered, and the second solder application (hereinafter referred to as the secondary solder) solders the part to be soldered. The timing of supplying the secondary solder is automatically set by a control device or manually set by an operator so that it coincides with the time when the primary solder forms the heat bridge. However, in practice, variations in the time when the primary solder forms the heat bridge vary depending on the surface condition of the land or other parts to be soldered, resulting in variations in soldering quality.

[0005] An object of the present disclosure is to provide a soldering apparatus and a non-transitory computer-readable medium that can obtain stable soldering quality that is not affected by variations in the time it takes for a heat bridge to form with solder.

[0006] One example embodiment provided by the present disclosure is a soldering device that melts solder using a heating tool to perform soldering, comprising: a solder supply unit that supplies solder to the heating tool; a drive unit that moves the heating tool; and a processing unit that causes the solder supply unit to supply a first amount of solder to a tip of the heating tool, moves the tip of the heating tool with the first amount of solder melted by the drive unit to a position where it will contact the part to be soldered, and causes the solder supply unit to supply a second amount of solder to the tip of the heating tool that has contacted the part to be soldered at a predetermined supply start timing, wherein the processing unit determines whether a heat bridge has been formed by the first amount of solder wetting the part to be soldered that is in contact with the tip of the heating tool, and adjusts the supply start timing so that the second amount of solder is supplied after it is determined that the heat bridge has been formed.

[0007] One example embodiment provided by the present disclosure is a non-transitory computer-readable medium having stored thereon a computer program executable by a processing unit of a control device mounted on a soldering device that performs soldering by melting solder with a heating tool, wherein when the computer program is executed, the control device: causes a solder supply unit to supply a first amount of solder to the tip of the heating tool; causes a drive unit to move the tip of the heating tool, from which the first amount of solder has melted, to a position where it will contact the part to be soldered; and, when causing the solder supply unit to supply a second amount of solder to the tip of the heating tool that is in contact with the part to be soldered at a predetermined solder supply start timing, determines whether a heat bridge has been formed by wetting the first amount of solder at the part to be soldered that is in contact with the heating tool; and adjusts the supply start timing so that the second amount of solder is supplied after it is determined that the heat bridge has been formed.

[0008] According to the configurations of the above aspects, since the second amount of solder (i.e., the secondary solder) is supplied after the heat bridge is formed, it is possible to suppress variations in the temperature of the soldered portion when the secondary solder is supplied, thereby achieving stable soldering quality that is not affected by variations in the time it takes for the first amount of solder (i.e., the primary solder) to form the heat bridge.

[0009] FIG. 1 is a schematic diagram illustrating the configuration of a soldering apparatus according to an embodiment of the present invention; FIG. 2 is a block diagram illustrating the functional configuration of the soldering apparatus; FIG. 3 is a control flow of soldering performed by a processing unit; FIG. 4 is a schematic diagram illustrating a process of supplying primary solder to the tip of a soldering iron; FIG. 5 is a schematic diagram illustrating a process of bringing the tip of a soldering iron into contact with a portion to be soldered; FIG. 6 is a schematic diagram illustrating a process of supplying secondary solder to a portion to be soldered; FIG. 7 is a schematic diagram illustrating a process of retracting the soldering iron after stopping the secondary solder supply; FIG. 8 is a control flow of automatic adjustment of supply start timing performed by a processing unit; FIG. 9 is a binarized image of a circuit board acquired by a camera;

[0010] An embodiment will be described in detail below with reference to the accompanying drawings. In each drawing used in the following description, the scale has been appropriately changed so that each element can be recognized. In the accompanying drawings, arrow F indicates the forward direction of the illustrated structure. Arrow B indicates the rearward direction of the illustrated structure. Arrow U indicates the upward direction of the illustrated structure. Arrow D indicates the downward direction of the illustrated structure. Arrow R indicates the rightward direction of the illustrated structure. Arrow L indicates the leftward direction of the illustrated structure. These directions are relative directions set for the soldering apparatus 1 illustrated in FIG. 1. These directional expressions are intended to be used for convenience of explanation and are not intended to limit the orientation of the structure during actual use.

[0011] (Configuration of Soldering Apparatus) Fig. 1 illustrates the configuration of a soldering apparatus 1 according to this embodiment. Fig. 2 illustrates the functional configuration of the soldering apparatus 1.

[0012] As shown in FIGS. 1 and 2, the soldering apparatus 1 according to this embodiment includes a support 10, a soldering unit 20, a drive section 30, a display section 40, and a control device 50.

[0013] 1, the support 10 includes a base 11, two support columns 12, a support bridge 13, and a mounting table 14. The two support columns 12 are erected on the base 11 with a gap between them. The support bridge 13 is installed between the upper ends of the two support columns 12. The mounting table 14 is movably disposed on the base 11. An object to be soldered (e.g., a printed circuit board) (not shown) is placed and fixed on the mounting table 14.

[0014] The soldering unit 20 includes a horizontally movable column 21 , a vertically movable column 22 , a support 23 , a soldering iron 24 , a solder receiving section 25 , and a solder feeder 26 .

[0015] The horizontally movable column 21 holds the vertically movable column 22, the support 23, the soldering iron 24, the solder accommodating section 25, and the solder feeder 26, and is configured to be movable in the left-right direction. The vertically movable column 22 holds the support 23, the soldering iron 24, the solder accommodating section 25, and the solder feeder 26, and is configured to be movable in the up-down direction.

[0016] A soldering iron 24 is attached to the support 23. The support 23 has, for example, an arc-shaped frame with a slot S1 formed therein. The attitude (mounting angle) of the soldering iron 24 can be changed by moving the soldering iron 24 along the slot S1 as indicated by arrow A1. The mounting angle of the soldering iron 24 relative to the support 23 can be changed, for example, by an operator.

[0017] The soldering iron 24 has a tip 24A and a heating portion 24B. The tip 24A is provided at the tip of the soldering iron 24. The heating portion 24B is built into the soldering iron 24. The heating portion 24B is configured to be able to heat the tip 24A by power supply from a power supply portion (not shown). The heating portion 24B heats the tip 24A of the soldering iron 24 to a predetermined temperature. The soldering iron 24 is an example of a heating tool of the present disclosure, and the tip 24A is an example of a tip portion of a heating tool of the present disclosure.

[0018] The solder accommodating section 25 accommodates a wire-shaped solder 27. The solder accommodating section 25 is fixed to the vertically movable column 22. Inside the solder accommodating section 25, the solder 27 is wound around a reel (not shown), and the solder 27 is unwound from the reel.

[0019] The solder feeder 26 is attached to the soldering iron 24. Solder 27 is supplied to the solder feeder 26 from the solder accommodation section 25. The solder feeder 26 is configured to be able to deliver the solder 27 from its tip toward the tip 24A. The solder feeder 26 supplies a predetermined amount of solder to the tip 24A of the soldering iron 24, which is heated by the heating section 24B. The solder feeder 26 is an example of a solder supply section of the present disclosure.

[0020] The driving unit 30 (FIG. 2) is configured to move the soldering iron 24 relative to the object to be soldered placed on the mounting table 14. Specifically, the driving unit 30 includes a plurality of actuators (not shown).

[0021] 1, a slot S2 extending in the front-rear direction is formed on the top surface of the base 11. One of the actuators moves the mounting table 14 in the front-rear direction along the slot S2, as indicated by an arrow A2.

[0022] For example, a slot S3 extending in the left-right direction is formed on the upper surface of the support bridge 13. One of the actuators moves the horizontally movable column 21 in the left-right direction along the slot S3 as shown by an arrow A3.

[0023] For example, one of the plurality of actuators moves the vertically movable column 22 in the up and down direction as indicated by arrow A4. The vertically movable column 22 has, at its tip, a head 22A to which the support portion 23 is connected. For example, one of the plurality of actuators rotates the head 22A around a rotation axis that substantially coincides with the vertical center axis of the vertically movable column 22 as indicated by arrow A5.

[0024] The display unit 40 is a general-purpose display device capable of displaying the operation screen of the soldering apparatus 1, etc. In this example, the display unit 40 is configured as an electrostatic or pressure-sensitive touch panel display. In this case, the input receiving unit 41 is realized as a GUI displayed on the display unit 40. The operator can input information necessary for soldering and instructions for performing soldering by bringing their fingers close to or into contact with the GUI. Note that the input receiving unit 41 may also be configured as a keyboard or mouse separate from the display unit 40.

[0025] The information necessary for soldering includes, for example, information on the object to be soldered (e.g., a circuit board), information on the soldering iron 24, and soldering conditions for setting operating parameters of each part of the soldering apparatus 1 (e.g., the amount of solder 27 supplied, the supply speed, the supply start timing, the supply stop timing, etc.). The input information is stored, for example, in a storage unit (not shown). The storage unit is configured with a storage device such as a memory, HDD (Hard Disk Drive), or SSD (Solid State Drive).

[0026] The Gerber data of the board, the CAD information of the board, and the CAD information of the soldering iron 24 may be acquired from the external device 60. The acquired data and information are stored in a storage unit (not shown).

[0027] The control device 50 is configured to control the operation of each component of the soldering device 1. As illustrated in Fig. 2, the control device 50 includes an input interface 51, a processing unit 52, and an output interface 53.

[0028] The input interface 51 is configured as a hardware interface that receives an input signal IS1 corresponding to information or instructions input by the input receiving unit 41 and an input signal IS2 including data or information from an external device 60. The input signal IS1 and the input signal IS2 may be analog signals or digital signals. When the input signal IS1 and the input signal IS2 are analog signals, the input interface 51 includes an appropriate conversion circuit including an A / D converter.

[0029] The processing unit 52 is configured to output control signals CS1 to CS3 that control the operation of each unit constituting the soldering apparatus 1 from the output interface 53. The output interface 53 is configured as a hardware interface. The control signals CS1 to CS3 may be analog signals or digital signals. If the control signals CS1 to CS3 are analog signals, the output interface 53 is equipped with an appropriate conversion circuit including a D / A converter.

[0030] The soldering apparatus 1 further includes a camera 70. The camera 70 is configured to acquire image information DI of the portion to be soldered. The camera 70 is attached to the support portion 23, for example, so as to capture an image of the board from above the board. The camera 70 is an example of an imaging sensor of the present disclosure. The image information DI of the portion to be soldered is an example of information regarding the wetting of the first amount of solder on the portion to be soldered.

[0031] The input interface 51 of the control device 50 is configured as a hardware interface that also receives image information DI from the camera 70. When the image information DI is in the form of analog data, the input interface 51 is provided with an appropriate conversion circuit including an A / D converter.

[0032] (Automatic soldering by soldering device) Next, automatic soldering by the soldering device 1 will be described with reference to Figures 3 to 7. Figure 3 shows a control flow of soldering executed by the processing unit 52 of the control device 50. Figures 4 to 7 are schematic diagrams for explaining each step of automatic soldering. Note that in Figures 4 to 7, only the tip 24A of the soldering iron 24 is shown. Also shown as the parts to be soldered are lands 81 formed on a substrate 80 and leads 82 soldered to the lands 81.

[0033] The processing unit 52 of the control device 50 performs soldering when it receives an input signal IS1 for performing soldering via the input interface 51. Note that the coordinates of the position to which the tip 24A of the soldering iron 24 moves, the angle value indicating the attitude, the amount and speed of solder to be supplied, the time that the tip 24A contacts the part to be soldered, and other parameters required for performing soldering are input by the operator via the input receiving unit 41, or are set in advance manually or automatically via the processing unit 52 and stored in the memory unit.

[0034] 3, first, the processing unit 52 outputs a control signal CS1 to the heating unit 24B to heat the tip 24A of the soldering iron 24 (STEP 1). Based on the control signal CS1, the heating unit 24B heats the tip 24A to a predetermined temperature at which the solder 27 can be melted.

[0035] Next, the processing unit 52 outputs a control signal CS2 to the drive unit 30 to move the tip 24A of the soldering iron 24 to the position (hereinafter referred to as the starting point) and posture shown in Figure 4 (STEP 2). Based on the control signal CS2, the drive unit 30 uses multiple actuators to move the mounting table 14, the horizontally movable column 21, and the vertically movable column 22. This moves the tip 24A to the starting point shown in Figure 4. Also, based on the control signal CS2, the drive unit 30 uses one of the multiple actuators to rotate the head 22A around the rotation axis. This moves the tip 24A to the posture shown in Figure 4.

[0036] Here, the starting point is the position when solder 27 (hereinafter referred to as the primary solder) is supplied to the tip of the soldering iron for the first time, as will be described later, and is set at a predetermined position away from the position where it comes into contact with the part to be soldered.

[0037] Next, the processing unit 52 outputs a control signal CS3 to the solder feeder 26 to supply the primary solder to the tip 24A (STEP 3). Based on the control signal CS3, the solder feeder 26 feeds the solder 27 to the tip 24A. The solder 27 supplied to the tip 24A is melted by the heated tip 24A.

[0038] The amount of primary solder to be supplied is calculated from board information such as Gerber data. The amount of primary solder to be supplied corresponds to the first amount in the present disclosure. For example, the processing unit 52 acquires board information from a storage unit (not shown) and automatically sets the amount of primary solder to be supplied based on the acquired board information. For example, the first amount is the amount of solder that can fill the through-hole portion of the land 81.

[0039] Next, the processing unit 52 outputs a control signal CS2 to the driving unit 30 to move the tip 24A of the soldering iron 24, on which the primary solder has melted, to the position shown in Fig. 5 (hereinafter referred to as the end point) (STEP 4). Based on the control signal CS2, the driving unit 30 moves the horizontally movable column 21 and the vertically movable column 22 using multiple actuators. As a result, the tip 24A is moved to the end point shown in Fig. 5.

[0040] Here, the end point is the position where soldering is performed by supplying a second solder 27 (hereinafter referred to as secondary solder) as described below, i.e., the position where the tip 24A of the soldering iron 24 comes into contact with the part to be soldered.

[0041] In this way, the tip 24A of the soldering iron 24 containing the molten primary solder comes into contact with the area to be soldered, and the primary solder wets the area to be soldered, forming a bridge (heat bridge) with the area to be soldered. In other words, the primary solder is supplied to form a heat bridge.

[0042] Next, the processing unit 52 outputs a control signal CS3 to the solder feeder 26 at a predetermined supply start timing to start supplying secondary solder to the tip 24A (STEP 5). As illustrated in Fig. 6, the solder feeder 26, based on the control signal CS3, feeds solder 27 to the tip 24A of the soldering iron 24 that is in contact with the area to be soldered. The secondary solder supplied to the tip 24A is melted by the heated tip 24A and supplied to the area to be soldered. The secondary solder supplied to the area to be soldered wets and spreads, thereby soldering the area to be soldered.

[0043] The amount of secondary solder supplied is automatically set by the processing unit 52, for example. For example, the total amount of solder supplied, including the amount of primary solder supplied and the amount of secondary solder supplied, is calculated from the board information. The amount of secondary solder supplied is then calculated from the calculated amount of primary solder supplied and the total amount of solder supplied. The amount of secondary solder supplied corresponds to the second amount in the present disclosure. The secondary solder supply rate can be calculated from the calculated amount of secondary solder supplied and the wire diameter of the solder 27.

[0044] Next, the processing unit 52 outputs a control signal CS3 to the solder feeder 26 at a predetermined timing to stop the supply of secondary solder to the tip 24A (STEP 6).

[0045] Next, the processing unit 52 outputs a control signal CS2 to the driving unit 30 at a predetermined retraction timing to move the soldering iron 24 to a retracted position away from the area to be soldered (STEP 7). As illustrated in Fig. 7, the driving unit 30 uses the multiple actuators to move the soldering iron 24 to the retracted position away from the area to be soldered based on the control signal CS2. Note that the retracted position may be, for example, the starting point or a position different from the starting point.

[0046] If the evacuation timing is set to the same timing as the supply stop timing, the processing in STEP 6 and the processing in STEP 7 may be performed simultaneously.

[0047] Here, the tip 24A of the soldering iron 24 and the part to be soldered are rigid bodies, and point or line contact creates high thermal resistance. Therefore, as described above, the primary solder is supplied so that the molten solder comes into contact with the part to be soldered before the secondary solder is supplied. A heat bridge is formed at the part to be soldered by the primary solder, and the heat bridge increases the contact area between the tip 24A of the soldering iron 24 and the part to be soldered. This reduces the thermal resistance between the tip 24A and the part to be soldered, allowing the heat from the tip 24A of the soldering iron 24 to be transferred efficiently and quickly to the part to be soldered.

[0048] The predetermined secondary solder supply start timing may be directly set as the time (point) at which the secondary solder supply starts. Alternatively, the supply start timing may be indirectly set as the time (period) from when the tip 24A of the soldering iron 24 contacts the area to be soldered to when the secondary solder supply starts. In other words, the processing unit 52 may be configured to measure the time from when the tip 24A of the soldering iron 24 contacts the area to be soldered, and to set the time when the measured time exceeds the predetermined time (period) as the supply start timing. In other words, the predetermined supply start timing in the present disclosure includes cases where it is directly set and cases where it is indirectly set.

[0049] The supply stop timing may also be set directly or indirectly. For example, the time (point) at which the supply of secondary solder is stopped may be directly set as the supply stop timing. Alternatively, the supply stop timing may be indirectly set as the time (period) from when the supply of secondary solder starts to when the supply stops. In other words, the processing unit 52 may be configured to measure the time from when the supply of secondary solder starts and set the timing at which the measured time exceeds a set time as the supply stop timing. Alternatively, the supply stop timing of secondary solder may be automatically set based on the supply start timing of secondary solder, the supply amount of secondary solder, and the supply speed of secondary solder.

[0050] Similarly, the retraction timing may be set directly or indirectly. For example, the time (point) at which the retraction of the soldering iron 24 begins may be directly set as the retraction timing. Alternatively, the retraction timing may be set as the heating time (period) of the area to be soldered, from when the tip 24A of the soldering iron 24 contacts the area to be soldered until the soldering iron 24 is retracted. The processing unit 52 may be configured to measure the time from when the tip 24A of the soldering iron 24 contacts the area to be soldered, and to determine the retraction timing as the time when the measured time exceeds the set time.

[0051] The processing unit 52 of the control device 50 according to the present disclosure determines whether a heat bridge has been formed by wetting the primary solder when the solder feeder 26 supplies secondary solder to the tip 24A of the soldering iron 24 that is in contact with the portion to be soldered at a preset solder supply start timing. The processing unit 52 is then configured to adjust the supply start timing so that the secondary solder is supplied after it is determined that a heat bridge has actually been formed.

[0052] (Automatic Adjustment of Secondary Solder Supply Start Timing) Automatic adjustment of the supply start timing by the processing unit 52 of the control device 50 will be described below with reference to Figures 8 and 9. Figure 8 illustrates an example of a control flow for automatic adjustment of the supply start timing executed by the processing unit 52. Figure 9 illustrates an example of a binarized image I acquired by imaging the substrate 80 in the state shown in Figure 5 from above with the camera 70.

[0053] 3, after the tip 24A of the soldering iron 24 is moved to the end point, when the preset supply start timing arrives (YES in STEP 11), the processing unit 52 determines whether a heat bridge has formed (STEP 12). If the processing unit 52 determines that a heat bridge has formed (YES in STEP 12), it controls the solder feeder 26 to start the secondary solder supply (STEP 5). In other words, in this case, the supply start timing is not adjusted, and the secondary solder supply is started based on the preset supply start timing.

[0054] For example, the processing unit 52 determines whether a heat bridge has been formed based on image information of the area to be soldered acquired by the camera 70 .

[0055] Specifically, the processing unit 52 is configured to determine whether a heat bridge has been formed by the difference between images of the area to be soldered taken over time by the camera 70 from above the area to be soldered after the tip 24A of the soldering iron 24 comes into contact with the area to be soldered.

[0056] For example, if the following formula is satisfied in the image acquired by the camera, the processing unit 52 determines that the primary solder has been wetted and a heat bridge has been formed.

[0057] Smax-S(t)>ST1 (Formula 1)

[0058] Smax is the maximum area of ​​the soldered portion after the tip 24A of the soldering iron 24 comes into contact with the portion to be soldered. Figure 9 is a binarized image I of the substrate 80 when the exposed area of ​​the land 81 is at its maximum area (Smax) after the tip 24A of the soldering iron 24 comes into contact with the land 81. In Figure 9, the exposed area of ​​the land 81 is shown in white, and the tip 24A, primary solder, substrate 80, and leads 82 are shown in black.

[0059] S(t) is the exposed area of ​​the land of the portion to be soldered at time t after the tip 24A of the soldering iron 24 with the molten primary solder comes into contact with the portion to be soldered. S(t) decreases over time due to wetting of the primary solder. In other words, the value of "Smax - S(t)" increases over time.

[0060] ST1 is a threshold value that is the area of ​​the primary solder that is estimated to be wetted by the primary solder, and is set appropriately based on the land and solder materials, etc.

[0061] The processing unit 52 may use artificial intelligence (AI) to improve the accuracy of determining whether a heat bridge has formed. The processing unit 52 may also configure a machine learning model. The machine learning model is, for example, a neural network model. In this case, the processing unit 52 may determine whether a heat bridge has formed using a trained model generated by training based on a large number of heat bridge images input in advance.

[0062] Returning to FIG. 8, in STEP 12, if processing unit 52 determines that a heat bridge has not been formed (NO in STEP 12), it does not supply secondary solder and repeats the process until it determines that a heat bridge has been formed.

[0063] Thereafter, when the processing unit 52 determines that a heat bridge has been formed (YES in STEP 12), it controls the solder feeder 26 to start supplying secondary solder (STEP 5). That is, the preset supply start timing is adjusted, and the supply of secondary solder is started at the adjusted supply start timing.

[0064] Here, when a heat bridge is formed in the area to be soldered, the temperature of the area to be soldered changes significantly, so there is a difference in the molten state of the secondary solder when it is supplied before the heat bridge is formed and when it is supplied after the heat bridge is formed.

[0065] However, the actual time at which the heat bridge is formed varies depending on factors such as the surface condition of the land to be soldered, so if automatic soldering is performed at a preset timing for starting the supply of secondary solder, there may be variations in the quality of the soldering.

[0066] 10 shows the temperature at a predetermined position on the land 81 estimated by finite element method (FEM) analysis based on a 3D model and the temperature actually measured at the predetermined position on the land 81. The predetermined position is the position farthest from the tip 24A on the surface of the land 81 that contacts the tip 24A (the upper surface of the land 81 in FIG. 4).

[0067] The vertical axis indicates the temperature at a predetermined position on the land 81, and the horizontal axis indicates the time from when the tip 24A contacts the land 81. The dashed line indicates the temperature of the land 81 estimated by FEM analysis, and the solid line indicates the temperature of the land 81 actually measured.

[0068] 10, the FEM analysis predicts the temperature based on the assumption that the solder 27 becomes wet and a heat bridge is formed when the tip 24A contacts the land 81. In other words, in the FEM analysis, the temperature of the land 81 rises instantly when the tip 24A contacts the land 81.

[0069] In contrast, as shown by the multiple solid lines in Fig. 10, there is variation in the actually measured temperature rise of the land 81. This is because in reality, wetting of the solder 27 does not occur immediately after the tip 24A comes into contact with the land 81, and the timing at which wetting of the solder 27 occurs (i.e., the time at which a heat bridge is formed) varies depending on the state of the land 81, etc.

[0070] Therefore, when automatic soldering is performed at a preset timing for starting the supply of secondary solder, variations in the temperature of the part being soldered may result in variations in the quality of the soldering.

[0071] In contrast, with the soldering apparatus 1 according to this embodiment, the secondary solder is supplied after the heat bridge is actually formed, which prevents variations in the temperature of the soldered part when the secondary solder is supplied, thereby achieving stable soldering quality that is not affected by variations in the time it takes for the primary solder to form a heat bridge.

[0072] Furthermore, heat bridges are formed by the wetting of the primary solder. The soldering apparatus 1 uses information about the wetting of the primary solder, so it can more accurately determine the formation of heat bridges.

[0073] Specifically, since the wetting of the primary solder is directly confirmed based on an image of the area to be soldered, the formation of a heat bridge can be determined more accurately.

[0074] In the above embodiment, when the supply start timing is reached in STEP 11 of FIG. 8 , the processing unit 52 determines whether a heat bridge has been formed in STEP 12. However, the processing unit 52 may be configured to determine whether a heat bridge has been formed before the supply start timing is reached. The processing unit 52 may also be configured to supply secondary solder if it is determined that a heat bridge has been formed before the supply start timing is reached. In other words, if a heat bridge has been formed before the preset supply start timing arrives, the supply start timing is adjusted.

[0075] In the above embodiment, the determination of whether a heat bridge has formed is based on an image of the soldered portion taken from above. However, the determination of whether a heat bridge has formed may also be based on an image of the soldered portion taken from another angle.

[0076] For example, the camera 70 may be configured to capture an image of the soldered portion from the side. The processing unit 52 may be configured to determine whether a heat bridge has formed based on an image of the soldered portion captured from the side. Specifically, for example, the processing unit 52 may be configured to determine that a heat bridge has formed when the contact angle of the solder 27 with the land 81 in the image is acute. The contact angle of the solder 27 with the land 81 refers to the angle between the tangent of the solder 27 and the surface of the land 81. Here, the wetting of the solder 27 with the land 81 refers to a state in which the molten solder does not form droplets on the surface of the land 81 due to its own surface tension. Therefore, it can be determined that the solder has wetted when the contact angle of the solder with the soldered portion is acute.

[0077] Alternatively, for example, camera 70 may be configured to include multiple cameras that capture images of the area to be soldered from multiple directions. Processing unit 52 may be configured to generate a 3D image based on image information from the multiple cameras, and to determine that a heat bridge has been formed based on the area of ​​the solder and the contact angle with the land in the 3D image.

[0078] Alternatively, instead of the camera 70, information regarding the wettability of the primary solder at the portion to be soldered may be obtained by another sensor.

[0079] For example, the soldering apparatus 1 may be configured to include a sensor (e.g., LiDAR) (not shown) that irradiates the area to be soldered with invisible light and detects the returned light reflected by the area to obtain information related to the shape of the area. The processing unit 52 may be configured to calculate the area of ​​the solder and the contact angle with the land based on the information obtained by the sensor, and to determine that a heat bridge has been formed based on the calculated area of ​​the solder and the contact angle with the land.

[0080] Alternatively, the soldering apparatus 1 may be configured to include a temperature sensor (not shown) that acquires temperature information of the portion to be soldered, the tip 24A of the soldering iron 24, or the primary solder at the portion to be soldered. The processing unit 52 may be configured to determine whether a heat bridge has been formed based on the temperature information. In other words, the "information regarding the wetting of the primary solder at the portion to be soldered" in this disclosure includes not only information about the portion to be soldered, but also information about the tip 24A of the soldering iron 24 or the primary solder.

[0081] For example, the temperature sensor is configured to detect the temperature of the portion to be soldered by contact or non-contact. Based on the temperature information acquired by the temperature sensor, the processing unit 52 determines that a heat bridge has been formed when the temperature of the portion to be soldered rises sharply.

[0082] Alternatively, the temperature sensor is configured to detect the temperature of the tip 24A of the soldering iron 24 by contact or non-contact. The temperature sensor may be disposed inside the tip 24A. The processing unit 52 determines that a heat bridge has formed when the temperature of the tip 24A of the soldering iron 24 suddenly drops. When a heat bridge is formed, heat is quickly transferred from the tip 24A to the portion to be soldered, so that the temperature of the portion to be soldered rises suddenly and the temperature of the tip 24A suddenly drops. Therefore, the formation of a heat bridge can be determined by detecting the sudden drop in temperature of the tip 24A.

[0083] Alternatively, the temperature sensor is configured to detect the temperature of the solder 27 at the portion to be soldered (e.g., land 81) in a non-contact manner. The processing unit 52 determines that a heat bridge has formed when the temperature of the solder suddenly drops. When a heat bridge is formed, heat is quickly conducted from the tip 24A through the solder to the portion to be soldered, causing the temperature of the portion to be soldered to rise suddenly and the temperature of the solder to drop suddenly at the same time. Therefore, the formation of a heat bridge can be determined by detecting the timing when the temperature of the solder suddenly drops.

[0084] In this way, by detecting the temperature of the area to be soldered, the tip 24A of the soldering iron 24, and the primary solder at the area to be soldered, which changes significantly at the time when a heat bridge is formed by the primary solder, it is possible to accurately determine the formation of a heat bridge.

[0085] The processing unit 52 may be configured to adjust the preset supply stop timing based on the supply start timing adjusted as described above. For example, the processing unit 52 changes (updates) the supply stop timing of the secondary solder by the time period for which the supply start timing of the secondary solder has been adjusted.

[0086] The timing to stop supplying the secondary solder is automatically set based on, for example, the timing to start supplying the secondary solder, the amount of the secondary solder to be supplied, and the supply speed of the secondary solder. Therefore, by adjusting the timing to stop supplying the secondary solder based on the adjusted timing to start supplying the secondary solder, it is possible to supply the set amount of secondary solder.

[0087] Alternatively, the processing unit 52 may be configured to adjust the preset retraction timing based on the supply start timing adjusted as described above.

[0088] For example, the time from when the tip 24A of the soldering iron 24 comes into contact with the area to be soldered until the secondary solder supply begins is defined as a first predetermined time (period), and the time from when the tip 24A comes into contact with the area to be soldered until the soldering iron is retracted is defined as a second predetermined time (period).

[0089] As described above, when the timing for starting the secondary solder supply is adjusted, the processing unit 52 adds the increase in the first predetermined time (period) to the second predetermined time (period). In other words, the processing unit 52 adds the increase in the time (period) adjusted based on the time (period) from when the tip 24A of the soldering iron 24 contacts the workpiece to when the secondary solder supply starts to the preset time until the soldering iron is retracted. This adjusts the preset retraction timing.

[0090] According to this configuration, the timing to start supplying the secondary solder, which is adjusted based on the formation of a heat bridge, is also reflected in the timing to retract the soldering iron 24, so that the soldering iron 24 can be prevented from retracting before the secondary solder has wetted and spread.

[0091] Alternatively, the processing unit 52 may be configured to adjust the secondary solder supply speed based on the supply start timing adjusted as described above.

[0092] Specifically, the processing unit 52 adjusts the supply speed of the secondary solder so that the supply of the secondary solder ends between the time when the supply of the secondary solder starts based on the supply start timing adjusted as described above and the time when the soldering iron 24 is retracted based on the predetermined retraction timing.

[0093] For example, if the adjusted supply start timing is later than the preset supply start timing, the supply speed of the secondary solder is adjusted so that the supply speed of the secondary solder is faster than the preset supply speed of the secondary solder.

[0094] By adjusting the secondary solder supply speed in this way, even if the supply start timing is delayed, the set amount of solder can be supplied by the preset retraction timing, and the initially set heating time from when the soldering iron tip comes into contact with the part to be soldered until it is retracted is not exceeded, so that electronic components can be prevented from being damaged by overheating the part to be soldered.

[0095] (Automatic Adjustment of Retraction Timing of Soldering Iron Tip) The processing unit 52 may be configured to automatically adjust the retraction timing of the tip 24A of the soldering iron 24 in addition to the supply start timing.

[0096] Specifically, the processing unit 52 may be configured to adjust the retraction timing so that the tip 24A of the soldering iron 24 is retracted after it is determined that the secondary solder has wetted and spread, when retracting the tip 24A of the soldering iron 24 at a preset retraction timing.

[0097] The automatic adjustment of the evacuation timing by the processing unit 52 of the control device 50 will be described below with reference to Fig. 11. Fig. 11 illustrates a control flow of the automatic adjustment of the evacuation timing executed by the processing unit 52.

[0098] 3 , when the preset retraction timing arrives (YES in STEP 21), the processing unit 52 determines whether the secondary solder has spread (STEP 22). If the processing unit 52 determines that the secondary solder has spread (YES in STEP 22), it controls the driving unit 30 to retract the soldering iron 24 (STEP 7). In other words, the retraction timing is not adjusted, and the soldering iron 24 is retracted based on the preset retraction timing.

[0099] For example, the processing unit 52 determines whether the secondary solder has spread based on image information of the area to be soldered acquired by the camera 70 .

[0100] Specifically, the processing unit 52 is configured to determine the wetting and spreading of the secondary solder from images of the area to be soldered taken over time by the camera 70 from above the area to be soldered after the tip 24A of the soldering iron 24 comes into contact with the area to be soldered.

[0101] For example, if the following formula is satisfied in the image acquired by the camera, the processing unit 52 determines that the secondary solder has spread.

[0102] S(t)<ST2 (Formula 2)

[0103] S(t) is the exposed area of ​​the portion to be soldered at time t after the tip 24A of the soldering iron 24 with the molten primary solder comes into contact with the portion to be soldered. For example, if the secondary solder spreads over the maximum area, the exposed area of ​​the land will be zero, and the land area will be displayed completely black in the binarized image.

[0104] ST2 is a threshold value, which is the area of ​​the land that is exposed when it is estimated that the secondary solder has spread, and is set appropriately based on the materials of the land and solder, etc.

[0105] The processing unit 52 may use AI to improve the accuracy of determining the wetting and spreading of the secondary solder.

[0106] Returning to FIG. 11, in STEP 22, if the processing unit 52 determines that the secondary solder has not spread (NO in STEP 22), it does not retract the soldering iron 24 and repeats the process until it determines in STEP 22 that the secondary solder has spread.

[0107] Thereafter, when the processing unit 52 determines that the secondary solder has spread (YES in STEP 22), it controls the driving unit 30 to retract the soldering iron 24 (STEP 7). That is, the preset retraction timing is adjusted, and the soldering iron 24 is retracted at the adjusted retraction timing.

[0108] For example, in the soldering in which the solder is supplied in two separate steps as in this example, if it is determined in STEP 22 that the secondary solder has spread, the driving unit 30 is controlled to immediately retract the soldering iron 24. In other words, the retraction timing is changed (updated) to the point in time when it is determined that the secondary solder has spread.

[0109] Alternatively, for example, in soldering in which a small amount of solder (hereinafter referred to as tertiary solder) is supplied after the secondary solder to give a glossy finish, the withdrawal timing is changed (updated) to coincide with or after the timing at which the supply of tertiary solder is stopped.

[0110] The temperature of the area to be soldered affects the spread of the secondary solder. For example, if the tip 24A of the soldering iron 24 is moved away from the area to be soldered before the secondary solder has spread, the temperature of the area to be soldered will drop, and the secondary solder may not spread sufficiently.

[0111] In contrast, with the soldering device 1 configured as described above, the soldering iron 24 is retracted after the secondary solder has actually spread, thereby realizing higher quality soldering that is not affected by variations in the spread of the secondary solder.

[0112] Specifically, since the wetting and spreading of the secondary solder is directly confirmed based on an image of the area to be soldered, the wetting and spreading of the secondary solder can be determined more accurately.

[0113] In the above control flow, when the retraction timing is reached in STEP 21 of Fig. 11 , the processing unit 52 determines whether the secondary solder is spreading in STEP 22. However, the processing unit 52 may be configured to determine whether the secondary solder is spreading before the retraction timing is reached. The processing unit 52 may also be configured to retract the soldering iron 24 if it is determined that the secondary solder is spreading before the retraction timing is reached. In other words, if the secondary solder is spreading before the preset retraction timing is reached, the retraction timing is adjusted.

[0114] In the above embodiment, the camera 70 has been described as an example of a sensor that acquires information about the wetting and spreading of the secondary solder in the soldered area. However, information about the wetting and spreading of the secondary solder in the soldered area may be acquired by another sensor.

[0115] For example, the soldering apparatus 1 may be configured to include a sensor (e.g., LiDAR) (not shown) that irradiates the area to be soldered with invisible light and detects the returned light reflected by the area to obtain information related to the shape of the area. The processing unit 52 may be configured to calculate the area of ​​the solder based on the information obtained by the sensor and determine that the secondary solder has spread based on the calculated area of ​​the solder.

[0116] In the above embodiment, the processing unit 52 may further be configured to measure the time elapsed since the soldering iron 24 came into contact with the portion to be soldered, and, when the time elapsed exceeds a predetermined time, to cause the driving unit 30 to retract the soldering iron 24 to the retracted position. The predetermined time is set appropriately based on the land, the solder material, etc.

[0117] The heating time of the area to be soldered is the time from when the tip 24A of the soldering iron 24 contacts the area to be soldered until when it is retracted. Therefore, if the retraction timing of the soldering iron 24 is adjusted to be later than the preset retraction timing as described above, the heating time of the area to be soldered will be longer. In such a case, if the area to be soldered is overheated, there is a possibility that the electronic components will be damaged.

[0118] Therefore, if the heating time of the area to be soldered based on the adjusted retraction timing becomes longer than the predetermined time, the soldering iron 24 is forcibly retracted, thereby preventing damage to the electronic components due to overheating of the area to be soldered.

[0119] (Example) Figure 12 illustrates the yield rate of joints soldered by the soldering apparatus 1. The vertical axis represents the yield rate. The horizontal axis represents the soldering conditions. Condition A represents the yield rate when neither the timing to start supplying secondary solder nor the timing to retract the soldering iron 24 is adjusted, i.e., when a preset program is used. Condition B represents the yield rate when the timing to start supplying secondary solder is automatically adjusted as described above. Condition C represents the yield rate when both the timing to start supplying secondary solder and the timing to retract the soldering iron 24 are automatically adjusted as described above.

[0120] A total of 342 soldered parts (lands and leads) with four widely different heat capacities of 0.00289 to 0.0250 J / K were prepared, soldering was performed on the soldered parts, and the joints of the soldered parts joined by soldering were visually inspected to calculate the yield rate.

[0121] 12, the yield rate was 80.6% under condition A, 94.4% under condition B, and 98.5% under condition C. In other words, it was found that the yield rate increased by automatically adjusting the timing to start supplying secondary solder. It was also found that the yield rate increased even further by automatically adjusting both the timing to start supplying secondary solder and the timing to retract the soldering iron 24.

[0122] The processing unit 52 of the control device 50 having the various functions described above can be realized by a dedicated integrated circuit such as a microcontroller, ASIC, or FPGA that includes a storage element in which a computer program for realizing the function is pre-installed. In this case, the storage element is an example of a non-transitory computer-readable medium in which a computer program is stored.

[0123] Alternatively, the processing unit 52 may be realized by a general-purpose microprocessor operating in cooperation with general-purpose memory. Examples of the general-purpose microprocessor include a CPU, an MPU, and a GPU. Examples of the general-purpose memory include a ROM and a RAM. In this case, a computer program for realizing the function may be stored in the ROM. The general-purpose microprocessor specifies at least a portion of the program stored in the ROM, expands it on the RAM, and executes the above-described processing in cooperation with the RAM. In this case, the general-purpose memory is an example of a non-transitory computer-readable medium on which a computer program is stored.

[0124] The processing unit 52 may be implemented by a combination of a general-purpose microprocessor and a dedicated integrated circuit.

[0125] The configurations described above are merely examples to facilitate understanding of the present disclosure. Each configuration example can be appropriately modified or combined with other configuration examples without departing from the spirit of the present disclosure.

Claims

1. A soldering apparatus that performs soldering by melting solder with a heating tool, comprising: a solder supply unit that supplies solder to the heating tool; a drive unit that moves the heating tool; and a processing unit that causes the solder supply unit to supply a first amount of solder to the tip of the heating tool, moves the tip of the heating tool where the first amount of solder has melted to a position in contact with the soldering site by the drive unit, and causes the solder supply unit to supply a second amount of solder to the tip of the heating tool in contact with the soldering site at a preset supply start timing. The processing unit: determines whether a heat bridge is formed by wetting of the first amount of solder at the soldering site where the tip of the heating tool contacts; adjusts the supply start timing so that the second amount of solder is supplied after it is determined that the heat bridge is formed. A soldering apparatus.

2. The soldering apparatus according to claim 1, further comprising a sensor that acquires information regarding wetting of the first amount of solder at the soldering site, wherein the processing unit determines whether the heat bridge is formed based on the information regarding wetting of the first amount of solder.

3. The sensor that acquires information regarding wetting of the first amount of solder is an imaging sensor that acquires image information of the soldering site, wherein the processing unit determines whether the heat bridge is formed based on a difference between images of the soldering site acquired by the imaging sensor over time after the tip of the heating tool contacts the soldering site. The soldering apparatus according to claim 2.

4. The sensor that acquires information regarding wetting of the first amount of solder is a temperature sensor that acquires temperature information, wherein the temperature sensor acquires temperature information of the soldering site, the tip of the heating tool, or the first amount of solder at the soldering site, wherein the processing unit determines whether the heat bridge is formed based on the temperature information. The soldering apparatus according to claim 2.

5. The apparatus further comprises a sensor configured to obtain information regarding the wet spread of the second amount of solder at the soldering site, wherein the processing unit is configured to move the heating tool to a retracted position spaced apart from the soldering site by the driving unit at a preset retraction timing, and the processing unit adjusts the retraction timing based on the information regarding the wet spread of the second amount of solder. The soldering apparatus according to claim 1.

6. The sensor configured to obtain information regarding the wet spread of the second amount of solder is an imaging sensor configured to obtain image information of the soldering site. The processing unit determines whether or not the second amount of solder has spread wet based on the image of the soldering site, and adjusts the retraction timing so that the heating tool is retracted after it is determined that the second amount of solder has spread wet. The soldering apparatus according to claim 5.

7. The processing unit measures the time after the tip of the heating tool contacts the soldering site, and when the measured time exceeds a predetermined time, the driving unit retracts the heating tool to the retracted position. The soldering apparatus according to claim 5.

8. The processing unit is configured to move the heating tool to a retracted position spaced apart from the soldering site by the driving unit at a preset retraction timing, and the processing unit adjusts the retraction timing based on the adjusted supply start timing. The soldering apparatus according to claim 1.

9. The processing unit is configured to move the heating tool to a retracted position spaced apart from the soldering site by the driving unit at a preset retraction timing, and the processing unit adjusts the supply rate of the second amount of solder so that the supply of the second amount of solder ends during the time from the start of the supply of the second amount of solder based on the adjusted supply start timing to the retraction of the heating tool based on the preset retraction timing. The soldering apparatus according to claim 1. A non-transitory computer-readable medium storing a computer program executable by a processing unit of a control device mounted on a soldering apparatus that performs soldering by melting solder with a heating tool, wherein when the computer program is executed, the control device causes a solder supply unit to supply a first amount of solder to a tip of the heating tool, causes a driving unit to move the tip of the heating tool, where the first amount of solder has melted, to a position in contact with a site to be soldered, and when causing the solder supply unit to supply a second amount of solder to the tip of the heating tool in contact with the site to be soldered at a preset solder supply start timing, determines whether a heat bridge is formed by wetting of the first amount of solder at the site to be soldered in contact with the heating tool, and adjusts the supply start timing so that the second amount of solder is supplied after it is determined that the heat bridge is formed. Non-transitory computer-readable medium.

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