Welding systems and welding methods

Abstract

The conveying mechanism (2) sequentially conveys the substrate (10) to the first position above the flux coating machine (3), the second position above the preheater (4), and the third position above the solder bath (5). The first non-contact displacement meter (6) and the first non-contact thermometer (7) are positioned above the jet nozzle (13). The control device (9) determines the warping of the substrate (10) during the welding of the substrate (10) based on the measurement results of the first non-contact displacement meter (6) during the welding of the substrate (10), and determines the temperature of the substrate (10) during the welding of the substrate (10) based on the measurement results of the first non-contact thermometer (7) during the welding of the substrate (10).

Description

Technical Field

[0001] This invention relates to a welding system and a welding method. Background Technology

[0002] A device has long been known that aims to avoid defects caused by flux residues applied during the soldering of substrates.

[0003] For example, the apparatus described in Patent Document 1 includes non-contact temperature sensors immediately after the preheater and after the solder jetting bath. The apparatus described in Patent Document 1 compares the substrate temperature measured by the non-contact temperature sensor immediately after the preheater with a preset optimal temperature, and controls the temperature of the preheater based on the comparison result. The apparatus described in Patent Document 1 also compares the substrate temperature measured by the non-contact temperature sensor immediately after the solder jetting bath with a preset optimal temperature, and controls the substrate transport speed, the solder temperature, and the preheater temperature based on the comparison result.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 7-142852 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, the intensity of the solder jet upon contact with the substrate varies from substrate to substrate. As a result, there are cases where substrates produce poor soldering results.

[0009] Therefore, the object of the present invention is to provide a welding system and welding method capable of determining the intensity of solder jets that come into contact with the substrate during welding.

[0010] Methods for solving problems

[0011] The welding system of the present invention comprises: a flux applicator for applying flux to a substrate; a preheater for preheating the substrate; a solder bath for storing molten solder; a solder bath heater for melting the solder in the solder bath; a jet nozzle for spraying the molten solder in the solder bath toward the substrate; a conveying mechanism for sequentially conveying the substrate to a first position above the flux applicator, a second position above the preheater, and a third position above the solder bath; a first non-contact displacement meter and a first non-contact thermometer disposed above the jet nozzle; and a control device for determining substrate warping during welding based on the measurement results of the first non-contact displacement meter, and determining the substrate temperature during welding based on the measurement results of the first non-contact thermometer.

[0012] The welding method of the present invention is a welding method in a welding system comprising a flux coating machine, a preheater, a solder bath, a jet nozzle, a conveying mechanism, a first non-contact displacement meter, a first non-contact thermometer, and a control device. The first non-contact displacement meter and the first non-contact thermometer are disposed above the jet nozzle. The welding method includes: a coating step in which the flux coating machine coats flux onto a substrate; a preheating step in which the preheater preheats the substrate; a spraying step in which the jet nozzle sprays molten solder from the solder bath toward the substrate; a conveying step in which the conveying mechanism sequentially conveys the substrate to a first position above the flux coating machine, a second position above the preheater, and a third position above the solder bath; and a determination step in which the control device determines the warping of the substrate during welding based on the measurement results of the first non-contact displacement meter during welding, and determines the temperature of the substrate during welding based on the measurement results of the first non-contact thermometer during welding.

[0013] Invention Effects

[0014] According to the present invention, it is possible to determine the intensity of the solder jet that touches the substrate during welding. Attached Figure Description

[0015] Figure 1 This is a schematic diagram showing the welding system 1 of embodiment 1.

[0016] Figure 2 (a) is a graph showing an example of the correlation between the "height of the jet nozzle" before adjustment and the welding defect rate. Figure 2 (b) is a graph showing an example of the correlation between the "height of solder jet" before adjustment and the solder defect rate. Figure 2 (c) is a graph showing an example of the correlation between "substrate warping" and soldering defect rate. Figure 2 (d) is a graph showing an example of the correlation between "substrate temperature" and soldering defect rate.

[0017] Figure 3 This is a flowchart illustrating the processing steps of the welding system 1 in Embodiment 1.

[0018] Figure 4 This is a flowchart illustrating the processing steps of the welding system 1 in Embodiment 1.

[0019] Figure 5 This is a schematic diagram of welding system 1 showing the "production preparation status".

[0020] Figure 6 (a) to (c) are schematic diagrams showing the relative positional relationship between the substrate 10 and the solder jet corresponding to the height 19 of the solder jet.

[0021] Figure 7 Figures (a) to (c) are used to illustrate the relationship between the warping of the substrate 10 and the distance between the substrate 10 and the jet nozzle 13 (secondary nozzle 13b).

[0022] Figure 8 This is a schematic diagram showing the welding system of Embodiment 2.

[0023] Figure 9 This is a schematic diagram showing the welding system of Embodiment 3.

[0024] Figure 10 This is a schematic diagram showing the welding system of embodiment 4.

[0025] Figure 11 This is a schematic diagram showing the welding system of embodiment 5.

[0026] Figure 12 This is a diagram showing the structure of the learning device 101.

[0027] Figure 13 It is a diagram representing the structure of a neural network.

[0028] Figure 14 This is a flowchart related to the learning process of the learning device 101.

[0029] Figure 15 This is a diagram showing the structure of the inference device 121.

[0030] Figure 16 This is a flowchart related to the reasoning processing of the reasoning device 121 and the control processing of the control device 9.

[0031] Figure 17 This is a diagram illustrating an example of temperature measurement performed using the non-contact thermometer 7a in Embodiment 6.

[0032] Figure 18This is a diagram showing an example of the measurement temperature of substrate 10 and the measurement temperature of a certain component A.

[0033] Figure 19 This is a diagram showing the hardware structure of the control device 9. Detailed Implementation

[0034] Hereinafter, the embodiments will be described with reference to the accompanying drawings.

[0035] Implementation Method 1

[0036] Figure 1 This is a schematic diagram showing the welding system 1 of embodiment 1.

[0037] The welding system 1 includes a conveying mechanism 2, a flux coating machine 3, a preheater 4, a solder tank 5, a jet nozzle 13, a jet motor 15, a solder tank heater 14, a non-contact displacement meter 6, a non-contact thermometer 7, a substrate detection sensor 8, and a control device 9.

[0038] The flux coating machine 3 applies flux 11 to the lower surface (soldering surface) of the substrate 10. The method for applying flux 11 can be spraying, foaming, or immersion. When using a spraying method, the flux coating machine 3 includes two fluid nozzles. The flux coating machine 3 mixes liquid flux with compressed air and sprays the mixture from the two fluid nozzles toward the substrate 10. The two fluid nozzles reciprocate in a direction perpendicular to the transport direction of the substrate 10, thereby applying flux 11 to the entire surface of the substrate 10.

[0039] The flux coating machine control unit 18 controls the amount of flux 11 applied. The amount of flux 11 applied (hereinafter referred to as the flux application amount) is determined by the flux flow rate, the compressed air pressure, and the moving speed of the two fluid nozzles. The flux application amount varies depending on the clogging of the nozzles in the flux coating machine 3, fluctuations in the operation of the flux coating machine 3, and fluctuations in the exhaust volume of the exhaust fan in the flux coating machine 3. If the flux application amount is too high, the time required for solvent evaporation during the preheating process using the preheater 4 is longer, and therefore the temperature of the substrate 10 cannot rise sufficiently. As a result, the warpage of the substrate 10 is less than expected. If the flux application amount is too low, the solvent evaporates immediately during the preheating process using the preheater 4, and therefore the temperature of the substrate 10 becomes too high. As a result, the warpage of the substrate 10 is greater.

[0040] The preheater 4 preheats the substrate 10. The purpose of preheating is to evaporate the solvent of the flux 11 and to heat the substrate 10 before soldering, thereby achieving the effect of removing the oxide film of the flux 11 and ensuring good soldering. As a heating method, infrared rays, far-infrared rays, or hot air can be used. The lower surface (soldering surface) of the substrate 10 can be heated only, or the upper surface (non-soldering surface, component surface) of the substrate 10 can also be heated.

[0041] Solder tank 5 stores molten solder 12.

[0042] The jet nozzle 13 is connected to the solder bath 5. The jet nozzle 13 sprays molten solder 12 from the solder bath 5, bringing the lower surface of the substrate 10 into contact with the molten solder 12. This performs soldering onto the substrate 10. The jet nozzle 13 includes a primary nozzle 13a and a secondary nozzle 13b. The primary nozzle 13a generates a strong wave, supplying molten solder to all corners of the soldering surface of the substrate 10. The secondary nozzle 13b generates a smooth wave, ensuring an appropriate amount of solder adheres to the substrate 10.

[0043] The solder bath heater 14 melts the solder in the solder bath 5.

[0044] The jet motor 15 rotates the impeller and feeds molten solder 12 from the solder tank 5 to the jet nozzle 13.

[0045] The conveying mechanism 2 moves the substrate 10 towards Figure 1 The substrate 10 is conveyed in the direction indicated by the arrow. The conveying mechanism 2 sequentially conveys the substrate 10 to the first position above the flux coating machine 3, the second position above the preheater 4, and the third position above the solder tank 5. The conveying angle of the substrate 10 is, for example, about 3 to 5 degrees.

[0046] The substrate detection sensor 8 is positioned above the solder bath 5, closer to the front of the third position. The substrate detection sensor 8 can measure using infrared, ultrasonic, or electromagnetic methods. The control device 9 can determine whether the substrate 10 has passed below the area where the substrate detection sensor 8 is located, based on the measurement result of the substrate detection sensor 8. In Embodiment 1, the substrate detection sensor 8 is positioned above the area between the preheater 4 (the second position) and the solder bath 5 (the third position).

[0047] The non-contact displacement gauge 6 is positioned above the primary nozzle 13a or the secondary nozzle 13b.

[0048] When the non-contact displacement gauge 6 is positioned above the primary nozzle 13a, it primarily prevents "no solder defect" (solder not adhering to the substrate 10 and the electrode of the component) and "insufficient solder rise" (solder not fully entering the through-hole of the substrate 10 and the electrode of the component inserted into the through-hole). When the non-contact displacement gauge 6 is positioned above the secondary nozzle 13b, in addition to preventing "insufficient solder rise," it also prevents "bridging defect" (solder connecting between terminals) and "excessive solder defect" (excessive solder amount).

[0049] As a non-contact displacement meter 6, the measurement method can be laser, ultrasonic, or electromagnetic wave.

[0050] A non-contact thermometer 7 is positioned above the primary nozzle 13a or the secondary nozzle 13b. The non-contact thermometer 7 may be, for example, an infrared camera or a radiation thermometer. For instance, the non-contact thermometer 7 may be positioned rearward of the non-contact displacement meter 6 in the substrate transport direction. Using the non-contact displacement meter 6, the warpage of the substrate 10 during production can be measured beforehand; therefore, the solder jet height can be controlled based on the amount of substrate warpage and the substrate temperature measured by the non-contact thermometer 7. However, the configuration of the non-contact thermometer 7 is not limited to this.

[0051] The control device 9 determines the height of the primary nozzle 13a or the secondary nozzle 13b (hereinafter referred to as "the height of the jet nozzle") based on the measurement results of the non-contact displacement meter 6 when the welding system is in a "production preparation state" where solder is not being sprayed from the jet nozzle 13. The "height of the jet nozzle" is the distance from the tip of the primary nozzle 13a or the secondary nozzle 13b to the bottom surface of the substrate without warping. Alternatively, the "height of the jet nozzle" is the distance from the tip of the primary nozzle 13a or the secondary nozzle 13b to the conveying mechanism 2.

[0052] The control device 9 adjusts the height of the jet nozzle based on the determined height of the jet nozzle. For example, the height of the jet nozzle can be adjusted by moving the primary nozzle 13a or the secondary nozzle 13b in the vertical direction using a unit not shown.

[0053] The control device 9 determines the height of the solder jet formed by the primary nozzle 13a or the secondary nozzle 13b (hereinafter referred to as the "solder jet height") based on the measurement results of the non-contact displacement meter 6 when the welding system sprays solder from the jet nozzle 13 and the substrate detection sensor 8 does not detect the substrate 10 in the "state before the welding is performed". During welding, flux residue and solder oxides (dross) are generated, thus changing the flow and intensity of the solder jet, and therefore the "solder jet height". The "solder jet height" changes due to the output of the jet motor 15, the liquid level of the molten solder 12 in the solder bath 5, and blockages within the jet nozzle 13. Because the "solder jet height" changes, the contact pattern of the solder jet with the substrate 10 changes, thus changing the temperature of the substrate 10.

[0054] The control device 9 adjusts the height of the solder jet based on the determined height of the solder jet. For example, the height of the solder jet can be adjusted by controlling the rotation speed of the jet motor 15.

[0055] The control device 9 determines the warping of the substrate 10 during the soldering process (hereinafter referred to as "substrate warping") based on the measurement results of the non-contact displacement meter 6 during the soldering of the substrate 10. Warping of the substrate 10 causes a temperature change in the substrate 10. The warping of the substrate is represented by the direction and amount of warping. The amount of warping is represented by the minimum distance between the substrate 10 and the non-contact displacement meter 6 (i.e., the displacement of the most warped portion of the substrate 10), or by a sequence of distance data between the substrate 10 and the non-contact displacement meter 6 (i.e., the displacement of multiple portions of the substrate 10).

[0056] The control device 9 determines the temperature of the substrate 10 during the soldering process (hereinafter referred to as "the temperature of the substrate") based on the measurement results of the non-contact thermometer 7 during the soldering process of the substrate 10. In this embodiment, instead of measuring the temperature of the soldering surface where the temperature is prone to rise, the temperature of the substrate 10 is measured from above, thus enabling the measurement of the transient temperature change of the substrate 10.

[0057] The control device 9 adjusts the height of the solder jet based on the "warping of the substrate" and the "temperature of the substrate" during the soldering of the substrate 10.

[0058] The control device 9 determines the quality of the soldering result based on the "substrate warpage" value measured by the non-contact displacement meter 6 and the "substrate temperature" measured by the non-contact thermometer 7. For example, the control device 9 can also use the "substrate warpage" value measured by the non-contact displacement meter 6 to check the image of the "substrate temperature" measured by the non-contact thermometer 7 to determine the quality of the soldering. As will be described later, due to the "substrate warpage," the contact state between the solder jet and the substrate changes, and therefore the "substrate temperature" changes. For example, even when the warpage of the substrate 10 is small and the temperature of the substrate 10 is low, a good product may still be obtained. Therefore, the appropriate substrate temperature varies depending on the amount of substrate warpage.

[0059] The soldering inspection device 16 inspects the soldered areas of the substrate 10 to determine whether the soldering is good or bad. The soldering inspection device 16 analyzes images of the soldering status of the substrate 10. The soldering inspection device 16 determines the quality of the soldering based on factors such as the presence or absence of icy solder adhered to the terminals of electronic components, the presence or absence of solder bridges, the area of ​​solder adhesion, and the gloss of the solder.

[0060] The control device 9 stores data obtained from the soldering of each substrate 10 (data on the success or failure of soldering corresponding to the "nozzle height" before adjustment, the "solder jet height" before adjustment, the "substrate warpage" during soldering, and the "substrate temperature" during soldering). Using the data obtained from the soldering of multiple substrates 10, the control device 9 generates correlation data between the "nozzle height" before adjustment, the "solder jet height" before adjustment, the "substrate warpage" during soldering, and the "substrate temperature" during soldering and the soldering defect rate. When the "nozzle height" before adjustment, the "solder jet height" before adjustment, the "substrate warpage" during soldering, and the "substrate temperature" during soldering are set to A, and the soldering defect rate is set to B, the correlation data between A and B can be set to any one of "no correlation," "strong correlation," and "weak correlation."

[0061] Figure 2 Figure (a) is an example of the correlation data between the "jet nozzle height" before adjustment and the welding defect rate. In this example, the control device 9 is able to set the correlation data between the "jet nozzle height" before adjustment and the welding defect rate to "unrelated".

[0062] Figure 2 Figure (b) is an example of the correlation data between the "solder jet height" before adjustment and the solder defect rate. In this example, the control device 9 is able to set the correlation data between the "solder jet height" before adjustment and the solder defect rate to "strong correlation".

[0063] Figure 2Figure (c) is an example of the correlation data between "substrate warping" and the welding defect rate during welding. In this example, the control device 9 is able to set the correlation data between "substrate warping" and the welding defect rate during welding to "irrelevant".

[0064] Figure 2 Figure (d) is an example of the correlation data between the "substrate temperature" during welding and the welding defect rate. In this example, the control device 9 is able to set the correlation data between the "substrate temperature" during welding and the welding defect rate to "weak correlation".

[0065] Based on relevant data, control device 9 determines which of the following is the cause of the soldering defect: the "jet nozzle height" before adjustment, the "solder jet height" before adjustment, "substrate warping," or "substrate temperature." Figure 2 In examples (a) to (d), the control device 9 is able to determine that the most important cause of poor soldering is the "height of the solder jet" before adjustment, and the second most important cause of poor soldering is the "temperature of the substrate".

[0066] The control device 9 is connected to the flux coating machine control unit 18, the preheater 4, the jet motor 15, and the solder tank heater 14. The control device 9 outputs the set control parameters to each of them. The flux coating machine control unit 18, the preheater 4, the jet motor 15, and the solder tank heater 14 operate according to the control parameters sent from the control device 9.

[0067] The control device 9 can adjust the control parameters based on measured and related data to reduce the soldering defect rate. The control parameters include the flux coating amount (flux application amount) of the flux coater 3, the set temperature of the preheater 4 (preheater temperature), the set value of the jet motor 15 (solder jet height), and the set temperature of the solder bath heater 14 (solder temperature). The control device 9 outputs the "flux application amount" to the flux coater control unit 18. The control device 9 outputs the "preheater temperature" to the preheater 4. The control device 9 outputs the "solder jet height" to the jet motor 15. The control device 9 outputs the "solder temperature" to the solder bath heater 14. The adjusted control parameters are applicable to the substrate being transported after adjustment.

[0068] For example, such as Figure 2 As shown in (b), when the average value of the "solder jet height" measured up to time t on a certain day is A, the control device 9 can also adjust the "solder jet height" after time t on that day to B, which is greater than A, so as to reduce the welding defect rate.

[0069] Control device 9 can also receive a specification of the adjustment amount of control parameters based on relevant data from the user, and adjust the control parameters accordingly. Control device 9 can also determine the adjustment amount of the control parameters through statistical processing based on relevant data and prompt the user, obtaining user approval before adjusting the control parameters. Control device 9 can also automatically adjust multiple control parameters at once by using AI-based relevant data.

[0070] Figure 3 and Figure 4 This is a flowchart illustrating the processing steps of the welding system 1 in Embodiment 1.

[0071] In step S101, when the welding system is in a "production preparation state" where solder is not being sprayed from the jet nozzle 13, the process proceeds to step S102. Figure 5 This is a schematic diagram of welding system 1 showing the "production preparation status".

[0072] In step S102, as Figure 5 As shown, the control device 9 determines the "height of the jet nozzle" based on the measurement results of the non-contact displacement meter 6. The "height of the jet nozzle" varies depending on the height of the solder bath 5 and the installation state of the jet nozzle 13. Since the non-contact displacement meter 6 is located above the jet nozzle 13, the control device 9 can determine the "height of the jet nozzle" even when the solder is not sprayed above the jet nozzle 13.

[0073] In step S103, the control device 9 confirms whether the determined "jet nozzle height" is a specified value. If the "jet nozzle height" is not a specified value, the process proceeds to step S104.

[0074] In step S104, the control device 9 adjusts the height of the jet nozzle to a predetermined value. If the height of the jet nozzle is high, the distance between the jet nozzle 13 and the substrate 10 is close, resulting in strong contact between the jet and the substrate 10. By lowering the height of the jet nozzle, the positional relationship between the non-warped substrate 10 and the jet nozzle 13 can be kept constant, thus maintaining a good soldering state.

[0075] In step S105, the control device 9 stores the "jet nozzle height" before and after adjustment. By recording how the adjusted "jet nozzle height" changes relative to the original "jet nozzle height", the amount of change can be managed, and it becomes easier to identify the cause when an unexpected defect occurs.

[0076] In step S106, the control device 9 causes the molten solder 12 to be ejected from the jet nozzle 13.

[0077] In step S107, when the welding system sprays solder from the jet nozzle 13 and the substrate detection sensor 8 does not detect the substrate 10, i.e., the "state of the substrate before welding is performed", the process proceeds to step S108.

[0078] In step S108, the control device 9 determines the height of the solder jet based on the measurement results of the non-contact displacement meter 6. Figure 6 Images (a) to (c) are schematic diagrams showing the relative positional relationship between the substrate 10 and the solder jet, corresponding to the height 19 of the solder jet. Figure 6 As shown in (a) to (c), if the height 19 of the solder jet changes, the distance between the substrate 10 and the solder jet changes. As a result, the intensity of the solder jet touching the substrate 10 changes, affecting the quality of the soldering.

[0079] In step S109, the control device 9 confirms whether the "height of the solder jet" is within the set range. If the "height of the solder jet" is outside the set range, the process proceeds to step S110.

[0080] In step S110, the control device 9 adjusts the height of the solder jet to ensure that the height of the solder jet is within a set range. Even during the production of the substrate 10, the control device 9 can adjust the height of the solder jet by changing the output of the jet motor 15. Because the height of the solder jet can be kept constant, the soldering process can be well maintained.

[0081] In step S111, the control device 9 stores the "solder jet height" before and after adjustment. By recording how the adjusted "solder jet height" changes relative to the original "solder jet height", the amount of change can be managed, and it becomes easier to identify the cause when an unexpected defect occurs.

[0082] In step S112, when the welding system detects the "substrate detection state" of the substrate 10 by the substrate detection sensor 8, the process proceeds to step S113.

[0083] In step S113, the control device 9 calculates the start time t0 of the substrate 10 passing through the solder jet and the end time t1 of the substrate 10 passing through the solder jet.

[0084] In step S114, when the welding system is "welding" as the substrate 10 passes over the solder jet (i.e., time t0 to time t1), the process proceeds to step S115.

[0085] In step S115, the non-contact displacement meter 6 measures the distance between the substrate 10 and the non-contact displacement meter 6.

[0086] In step S116, the control device 9 determines the warping of the substrate 10 based on the measurement results of the non-contact displacement meter 6.

[0087] Figure 7 Figures (a) to (c) are used to illustrate the relationship between the warping of the substrate 10 and the distance between the substrate 10 and the jet nozzle 13 (secondary nozzle 13b).

[0088] The warpage of substrate 10 is caused by the copper foil pattern of substrate 10, the thickness of substrate 10, the heat received by substrate 10 up to the flow soldering process, the moisture absorption of substrate 10 up to the flow soldering process, the temperature of preheater 4, and the temperature of substrate 10 in contact with solder jets. Since the warpage of substrate 10 varies for each substrate produced, the warpage of substrate 10 during soldering is different.

[0089] like Figure 7 As shown in (a) to (c), the distance between the substrate 10 and the jet nozzle 13 changes when the size of the warping of the substrate 10 changes.

[0090] Even if the solder jet height 19 remains constant, the distance between the substrate 10 and the jet nozzle 13 decreases when the substrate 10 is warped in a downward convex direction. As a result, due to excessive contact between the jet and the substrate 10, soldering defects may occur, such as overheating leading to flux deactivation or solder overflowing onto the upper surface of the substrate 10. For example, excessive contact between the jet and the substrate 10 results in excessive warping. If the warping is excessive, a vicious cycle can occur where the jet further over-contacts the substrate, causing the warping to increase further. When the substrate 10 is warped in a downward convex direction, the greater the warping, the stronger the contact between the jet and the substrate 10, thus making soldering defects more likely to occur.

[0091] Even if the solder jet height 19 remains constant, the distance between the substrate 10 and the jet nozzle 13 increases when the substrate 10 is warped upwards in a convex shape. As a result, the contact between the jet and the substrate 10 weakens, and the solder cannot wet and diffuse into the substrate 10. Consequently, soldering defects such as poor solder or insufficient solder filling of vias may occur. The greater the upward warping of the substrate 10, the weaker the contact between the jet and the substrate 10, thus making soldering defects more likely to occur.

[0092] To address this issue, in this embodiment, in step S117, the control device 9 adjusts the "solder jet height" based on the warpage of the substrate. More specifically, when the substrate 10 is warped in a convex shape in the downward direction, the control device 9 lowers the "solder jet height" as the warpage increases. When the substrate 10 is warped in a convex shape in the upward direction, the control device 9 raises the "solder jet height" as the warpage increases. Alternatively, the "solder jet height" can be controlled based on warpage changes during soldering and temperature measurement results.

[0093] In step S118, the control device 9 determines the temperature of the substrate 10 (the temperature of the substrate) based on the measurement result of the non-contact thermometer 7.

[0094] The height 19 of the solder jet varies due to the pulsation of the jet motor 15 and the slag from solder oxides generated by solder jetting clogging the jet nozzle 13. However, measuring the height 19 of the solder jet is difficult while the substrate 10 passes over the solder jet. In contrast, the temperature of the substrate 10 can be measured by a non-contact thermometer 7, which can be used to evaluate the height 19 of the solder jet, i.e., the intensity of the solder jet. The lower the height 19 of the solder jet, the weaker the solder jet in contact with the substrate 10, and therefore the less heat transfer from the solder jet to the substrate 10, resulting in a lower temperature of the substrate 10. On the other hand, the higher the height 19 of the solder jet, the stronger the solder jet in contact with the substrate 10, and therefore the greater the heat transfer from the solder jet to the substrate 10, resulting in a higher temperature of the substrate 10. The temperature of the substrate 10 during contact with the solder jet is affected not only by the height 19 of the solder jet, but also by the temperature of the substrate before it is put into the soldering system 1, the heat of vaporization of the solvent in the flux 11 generated by the flux coater 3, and the preheating of the preheater 4.

[0095] In step S119, the control device 9 adjusts the height of the solder jet based on the temperature of the substrate. More specifically, the higher the temperature of the substrate, the lower the height of the solder jet.

[0096] In step S120, the control device 9 stores the warpage of the substrate and the temperature of the substrate.

[0097] In step S121, when the welding system is in the "welding completed state" where the substrate 10 has completely passed over the solder jet (i.e., time t1), the process proceeds to step S121.

[0098] In step S122, the welding inspection device 16 inspects the welding status of the substrate 10 and outputs the result of whether the welding is good or bad to the control device 9. The control device 9 stores the result of whether the welding is good or bad.

[0099] In step S123, the control device 9 uses data obtained from soldering multiple substrates 10 (corresponding to the "height of the jet nozzle" before adjustment determined in step S102, the "height of the solder jet" before adjustment determined in step S108, the "warpage of the substrate" during the soldering of the substrate 10 determined in step S116, and the "temperature of the substrate" during the soldering of the substrate 10 determined in step S118, and the soldering quality determined in step S122) to generate correlation data indicating the relationship between the "height of the jet nozzle" before adjustment, the "height of the solder jet" before adjustment, the "warpage of the substrate" during the soldering of the substrate 10, and the "temperature of the substrate" during the soldering of the substrate 10 and the soldering defect rate. Based on this correlation data, the control device 9 can determine which of the following is the cause of the soldering defect: the "height of the jet nozzle" before adjustment, the "height of the solder jet" before adjustment, the "warpage of the substrate" during the soldering of the substrate 10, or the "temperature of the substrate" during the soldering of the substrate 10.

[0100] In step S124, the control device 9 adjusts the control parameters according to relevant data to reduce the welding defect rate.

[0101] After that, the process returns to step S107 to process the substrate 10 that will be transported next.

[0102] As described above, the welding system of this embodiment can use the non-contact displacement meter 6 and the non-contact thermometer 7 to manage the "height of the jet nozzle" before adjustment, the "height of the solder jet" before adjustment, the "warping of the substrate" during welding, and the "temperature of the substrate" during welding, which are the causes of welding defects, thereby stabilizing the quality of welding.

[0103] The welding system of this embodiment can identify key causes of welding defects by generating relevant data showing the relationship between the "height of the jet nozzle" before adjustment, the "height of the solder jet" before adjustment, the "warping of the substrate" during welding, and the "temperature of the substrate" during welding, and the welding defect rate. This prevents time losses caused by production stoppages to identify defects, thereby improving substrate productivity.

[0104] The "substrate temperature" during soldering, which affects soldering quality, is influenced by the intensity of the jet that touches the substrate 10, namely the "substrate warpage," the "jet nozzle height," and the "solder jet height." These parameters interact with each other, so by finding the optimal combination of these parameters, soldering quality can be further improved.

[0105] Implementation Method 2

[0106] Figure 8This is a schematic diagram showing the welding system of Embodiment 2. The welding system of Embodiment 2 differs from the welding system of Embodiment 1 in that the welding system of Embodiment 2 includes a non-contact displacement gauge 6a and a non-contact thermometer 7a.

[0107] Non-contact displacement gauge 6a and non-contact thermometer 7a are positioned above the second position of the transport substrate 10, which serves as the preheater 4, and the third position of the transport substrate 10, which serves as the solder bath 5.

[0108] The non-contact displacement gauge 6 can be measured using laser, ultrasonic, or electromagnetic wave methods. The non-contact thermometer 7 is, for example, composed of an infrared camera or a radiation thermometer.

[0109] The control device 9 determines the "warping of the substrate" after the substrate 10 is preheated by the preheater 4 and before the substrate 10 is soldered, based on the measurement results of the non-contact displacement meter 6a. Because the substrate 10 is warped after being heated by the preheater 4, there is a possibility that components disposed on the substrate 10 may float or tilt. In this embodiment, the possibility of these occurrences can be determined based on the measurement results of the non-contact displacement meter 6a.

[0110] The control device 9 determines the "temperature of the substrate" after the substrate 10 is preheated by the preheater 4 and before the substrate 10 is soldered, based on the measurement results of the non-contact thermometer 7a.

[0111] In this embodiment, in addition to the determination in Embodiment 1, it is also possible to determine the "warping of the substrate" and the "temperature of the substrate" after the substrate 10 is preheated by the preheater 4 and before the substrate 10 is soldered. Therefore, in this embodiment, it is possible to determine whether the cause of poor soldering is the flux application or the temperature of the preheater 4 after the substrate 10 is preheated by the preheater 4 and before soldering, or the "height of the solder jet", "height of the jet nozzle" or "warping of the substrate" during soldering.

[0112] The control device 9 can also adjust the temperature of the preheater 4 and the height of the solder jet based on the "warping of the substrate" and the "temperature of the substrate" after the substrate 10 is preheated and before the substrate 10 is soldered.

[0113] For example, if the temperature of the substrate 10 is higher than a reference value after the substrate 10 is preheated and before it is soldered, and the substrate 10 is warped downwards in a convex shape with a warp value greater than a reference value, the control device 9 lowers the temperature of the preheater 4. If the temperature of the substrate 10 is lower than a reference value after the substrate 10 is preheated and before it is soldered, and the substrate 10 is warped downwards in a convex shape with a warp value greater than a reference value, the control device 9 raises the temperature of the preheater 4. If the temperature of the substrate 10 is higher than a reference value after the substrate 10 is preheated and before it is soldered, and the substrate 10 is warped downwards in a convex shape with a warp value less than a reference value, the control device 9 lowers the temperature of the preheater 4. If the temperature of the substrate 10 is lower than a reference value after the substrate 10 is preheated and before it is soldered, and the substrate 10 is warped downwards in a convex shape with a warp value less than a reference value, the control device 9 raises the temperature of the preheater 4.

[0114] When the substrate 10 is preheated and before it is soldered, if the substrate 10 is convex in the downward direction, the greater the warping amount, the lower the "solder jet height". When the substrate 10 is preheated and before it is soldered, if the substrate 10 is convex in the upward direction, the greater the warping amount, the higher the "solder jet height".

[0115] Implementation Method 3

[0116] Figure 9 This is a schematic diagram showing the welding system of Embodiment 3. The welding system of Embodiment 3 differs from the welding system of Embodiment 2 in that the welding system of Embodiment 3 includes a non-contact displacement gauge 6b and a non-contact thermometer 7b.

[0117] Non-contact displacement gauge 6b and non-contact thermometer 7b are positioned above the first position of the conveyor plate 10 above the flux coating machine 3 and the second position of the conveyor plate 10 above the preheater 4.

[0118] As a non-contact displacement gauge 6b, the measurement method can be laser, ultrasonic, or electromagnetic wave. The non-contact thermometer 7b is, for example, composed of an infrared camera or a radiation thermometer.

[0119] The control device 9 determines, based on the measurement results of the non-contact displacement meter 6b, whether the components disposed on the substrate 10 have floated off the substrate 10 after the flux coating machine 3 has applied flux to the substrate 10. In the flux coating machine 3, the flux is sprayed from below the substrate 10, therefore, there is a possibility that the disposed components may float due to air pressure. In this embodiment, the non-contact displacement meter 6b can detect whether the components have floated off the substrate 10.

[0120] The control device 9 determines the "substrate temperature" after the flux coater 3 applies flux to the substrate 10 based on the measurement results of the non-contact thermometer 7b. The control device 9 can also estimate the amount of flux applied to the substrate 10 and the amount of solvent that naturally evaporates based on the "substrate temperature" after flux application. For example, the control device 9 can estimate that the amount of flux applied is small when the "substrate temperature" is high, and that the amount of flux applied is large when the "substrate temperature" is low. The pump flow rate of the flux coater 3 and the actual amount of flux adhered to the substrate may sometimes differ. When the flow rate is constant and the temperature of the substrate 10 after coating is high, it is determined that the actual amount of flux adhered is small. Based on this result, the control device 9 can also change the conditions of the flux coater 3.

[0121] According to this embodiment, in the event of a welding defect, the process that caused the welding defect can be determined by comparing the measurement results after flux application, the measurement results after preheating by the preheater in Embodiment 2, and the measurement results during welding in Embodiment 1.

[0122] Implementation Method 4

[0123] Figure 10 This is a schematic diagram showing the welding system of Embodiment 4. The welding system of Embodiment 4 differs from the welding system of Embodiment 3 in that the welding system of Embodiment 4 includes a non-contact displacement gauge 6c and a non-contact thermometer 7c.

[0124] After being transported to the fourth position, the substrate 10 is transported above the flux coating machine 3, i.e., to the first position.

[0125] The non-contact displacement meter 6c and the non-contact thermometer 7c are positioned above the fourth position of the transport substrate 10.

[0126] As a non-contact displacement gauge 6c, the measurement method can be laser, ultrasonic, or electromagnetic wave. A non-contact thermometer 7c is, for example, composed of an infrared camera or a radiation thermometer.

[0127] Based on the measurement results of the non-contact displacement meter 6c, the control device 9 determines the "warping of the substrate" before flux application.

[0128] The control device 9 determines the "substrate temperature" before flux application based on the measurement results of the non-contact thermometer 7c.

[0129] The control device 9 can also adjust the temperature of the preheater 4 and the height of the solder jet based on the "substrate warpage" and "substrate temperature" before flux application. For example, when the "substrate temperature" of the substrate 10 before flux application is lower than a reference value, the control device 9 increases the temperature of the preheater 4. When the "substrate temperature" of the substrate 10 before flux application is higher than a reference value, the control device 9 decreases the temperature of the preheater 4. The higher the "substrate temperature" of the substrate 10 before flux application, the lower the "solder jet height" of the control device 9. When the substrate 10 is warped in a downward convex direction before flux application, the greater the warpage, the lower the "solder jet height" of the control device 9. When the substrate 10 is warped in an upward convex direction before flux application, the greater the warpage, the higher the "solder jet height" of the control device 9.

[0130] According to this embodiment, in the event of a welding defect, the process that caused the welding defect can be determined by comparing the measurement results before flux application, the measurement results after flux application in Embodiment 3, the measurement results after preheating by the preheater in Embodiment 2, and the measurement results during welding in Embodiment 1.

[0131] According to this embodiment, by comparing the change in substrate temperature before and after flux coating and the result of the flow meter of flux coating machine 3, the actual amount of flux applied to substrate 10 can be predicted.

[0132] Implementation Method 5

[0133] Figure 11 This is a schematic diagram showing the welding system of Embodiment 5. The difference between the welding system of Embodiment 5 and the welding system of Embodiment 1 is that the control device 9 of the welding system of Embodiment 5 includes a learning device 101 and a reasoning device 121.

[0134] Figure 12 This is a diagram showing the structure of the learning device 101.

[0135] The learning device 101 includes a data acquisition unit 102 and a model generation unit 103.

[0136] The data provided to the learning device 101 is generated by the control device 9.

[0137] Control device 9 according to embodiment 1 Figure 3The control parameters are adjusted based on the following parameters: the height of the jet nozzle before adjustment determined in step S102, the height of the solder jet before adjustment determined in step S108, the warping of the substrate 10 during soldering determined in step S116, the temperature of the substrate during soldering determined in step S117, and the quality of soldering determined in step S121.

[0138] The control parameters include the “flux application amount” (a), “solder jet height” (b), “solder temperature” (c), and “preheater temperature” (d) described in Implementation 1.

[0139] When the soldering defect rate is lower than the threshold when the height of the jet nozzle is x, the height of the solder jet is y, the warpage of the substrate is z, and the temperature of the substrate is w, the control device 9 does not change the currently set control parameters, but stores the currently set control parameters (a, b, c, d) as control parameters corresponding to (x, y, z, w).

[0140] When the soldering defect rate exceeds the threshold when the height of the jet nozzle is x, the height of the solder jet is y, the warpage of the substrate is z, and the temperature of the substrate is w, the control device 9 changes the currently set control parameters.

[0141] For example, control device 9 selects one of four control parameters (a, b, c, d). Control device 9 changes the value of the selected control parameter multiple times each time, using a preset value. When the result of changing the control parameter is that the welding defect rate is below a threshold, control device 9 stores the current control parameter (a, b, c, d) as the control parameter corresponding to (x, y, z, w). When the welding defect rate remains above the threshold even after changing the selected control parameter, control device 9 selects other control parameters from the four control parameters (a, b, c, d) and repeats the above process. Control device 9 can also increase the number of control parameters that can be changed when the welding defect rate remains above the threshold by changing only one control parameter.

[0142] The data acquisition unit 102 acquires learning data B1, including the "height of the jet nozzle" before adjustment, the "height of the solder jet" before adjustment, the "warping of the substrate 10" during soldering, and the "temperature of the substrate 10" during soldering, and learning data B2 (correct scheme), including control parameters (flux application amount, solder jet height, solder temperature, and preheater temperature). That is, the data acquisition unit 102 reads (x, y, z, w) and (a, b, c, d) generated and correspondingly stored by the control device 9, uses (x, y, z, w) as learning data B1, and uses (a, b, c, d) as learning data B2 (correct scheme).

[0143] The model generation unit 103 generates a learned model based on a combination of learning data B1 and learning data B1 (correct scheme). This learned model estimates control parameters (flux application amount, solder jet height, solder temperature, and preheater temperature) based on the "jet nozzle height" before adjustment, the "solder jet height" before adjustment, the "board warping" during the soldering of the board 10, and the "board temperature" during the soldering of the board 10. The model generation unit 103 stores the generated learned model in the learned model storage device 111.

[0144] The learning algorithm used by the model generation unit 103 can be a known algorithm such as supervised learning, unsupervised learning, or reinforcement learning. As an example, the case of applying a neural network will be explained. The model generation unit 103, for example, learns control parameters through so-called supervised learning based on a neural network model. Here, supervised learning refers to the method of learning features located in the learning data by providing a set of input and result (label) data to a learning device, and inferring results from the input.

[0145] A neural network consists of an input layer composed of multiple neurons, an intermediate layer (hidden layer) composed of multiple neurons, and an output layer composed of multiple neurons. The intermediate layer can be one or more layers.

[0146] Figure 13 It is a diagram representing the structure of a neural network.

[0147] If the model generation unit 103 is Figure 13 In a three-layer neural network as shown, when multiple inputs are fed into the input layer (X1-X4), the value is multiplied by weights W1 (w11-w18) and fed into the intermediate layer (Y1-Y2). The result is then multiplied by weights W2 (w21-w28) and output from the output layer (Z1-Z4). The output varies depending on the values ​​of weights W1 and W2.

[0148] In this application, the neural network learns control parameters through so-called supervised learning based on a combination of learning data B1 and learning data B2 (correct scheme) acquired by the data acquisition unit 102.

[0149] That is, the neural network learns by adjusting the weights W1 and W2 so that the result output from the output layer when the learning data B1 is input into the input layer is close to the learning data B2 (the correct solution).

[0150] The model generation unit 103 generates a learned model by performing the learning process described above.

[0151] The learned model storage device 111 stores the learned model output from the model generation unit 103.

[0152] Next, the learning process performed by the learning device 101 will be explained. Figure 14 This is a flowchart related to the learning process of the learning device 101.

[0153] In step S301, the data acquisition unit 102 acquires learning data B1 and learning data B2 (correct scheme). The data acquisition unit 102 may also acquire learning data B1 and learning data B2 (correct scheme) simultaneously. Alternatively, as long as learning data B1 and learning data B2 (correct scheme) can be input in association, the data acquisition unit 102 may acquire learning data B1 and learning data B2 (correct scheme) at different times.

[0154] In step S302, the model generation unit 103 generates a learned model based on the combination of the acquired learning data B1 and learning data B2 (correct scheme) through so-called supervised learning. The learned model estimates control parameters (flux application amount, solder jet height, solder temperature, and preheater temperature) based on the "height of the jet nozzle" before adjustment, the "height of the solder jet" before adjustment, the "warping of the substrate 10" during the soldering of the substrate 10, and the "temperature of the substrate 10" during the soldering of the substrate 10.

[0155] In step S303, the model generation unit 103 stores the generated learned model in the learned model storage device 111.

[0156] Figure 15 This is a diagram showing the structure of the inference device 121. The inference device 121 includes a data acquisition unit 122 and an inference unit 123.

[0157] The data acquisition unit 122 acquires input data B1, which includes data from Embodiment 1. Figure 3 The flowchart includes the "height of the jet nozzle" determined in step S102 before adjustment, the "height of the solder jet" determined in step S108 before adjustment, the "warping of the substrate 10" determined in step S116 during the soldering of the substrate 10, and the "temperature of the substrate 10" determined in step S117 during the soldering of the substrate 10.

[0158] The inference unit 123 uses the learned model stored in the learned model storage device 111 and the input data B1 to estimate the control parameters (flux application amount, solder jet height, solder temperature, and preheater temperature). The learned model estimates the control parameters (flux application amount, solder jet height, solder temperature, and preheater temperature) based on the "jet nozzle height" before adjustment, the "solder jet height" before adjustment, the "board warping" during the soldering of the board 10, and the "board temperature" during the soldering of the board 10. That is, the inference unit 123 outputs the control parameters (flux application amount, solder jet height, solder temperature, and preheater temperature) inferred based on the input data B1 acquired by the data acquisition unit 122 by inputting the learned model into the learned model.

[0159] Next, the reasoning of the reasoning device 121 and the control of the control device 9 will be explained. Figure 16 This is a flowchart related to the reasoning processing of the reasoning device 121 and the control processing of the control device 9. (Replaces) Figure 4 The flowchart steps S123 are used to perform these processes.

[0160] In step S401, the data acquisition unit 122 acquires input data B1 including the "height of the jet nozzle" before adjustment, the "height of the solder jet" before adjustment, the "warping of the substrate 10" during the soldering of the substrate 10, and the "temperature of the substrate 10" during the soldering of the substrate 10.

[0161] In step S402, the inference unit 123 estimates the control parameters (flux application amount, solder jet height, solder temperature, and preheater temperature) by inputting input data B1 into the learned model stored in the learned model storage device 111. The learned model estimates the control parameters (flux application amount, solder jet height, solder temperature, and preheater temperature) based on the "jet nozzle height" before adjustment, the "solder jet height" before adjustment, the "board warping" during the soldering of the board 10, and the "board temperature" during the soldering of the board 10.

[0162] In step S403, the inference unit 123 outputs the estimated control parameters (flux application amount, solder jet height, solder temperature, and preheater temperature) to the flux coating machine control unit 18, the jet motor 15, the solder bath heater, and the preheater 4. The inference unit 123 outputs "flux application amount" to the flux coating machine control unit 18. The inference unit 123 outputs "solder jet height" to the jet motor 15. The inference unit 123 outputs "solder temperature" to the solder bath heater. The inference unit 123 outputs "preheater temperature" to the preheater 4.

[0163] In step S404, the flux coating machine control unit 18, the jet motor 15, the solder bath heater 14, and the preheater 4 control the welding according to the received control parameters.

[0164] In this embodiment, the case where supervised learning is applied in the learning algorithm used by the model generation unit 103 has been described, but it is not limited to this. Regarding the learning algorithm, in addition to supervised learning, reinforcement learning, unsupervised learning, or semi-supervised learning can also be applied.

[0165] The model generation unit 103 can also use learning data created in multiple welding systems 1 to generate a learned model. The model generation unit 103 can acquire learning data from multiple welding systems 1 used in the same area, or it can use learning data collected from multiple welding systems 1 operating independently in different areas to generate a learned model. The welding systems 1 from which the learning data is collected can also be added to or removed from the object midway. Furthermore, the learned model generated for one welding system 1 can be applied to other welding systems 1, and the learned model can be updated through relearning.

[0166] The learning algorithm used in the model generation unit 103 can be deep learning, which learns by extracting the feature quantity itself, or it can be machine learning performed according to other well-known methods, such as genetic programming, functional logic programming, or support vector machines.

[0167] The learning device 101 and the reasoning device 121 can also be built into the welding system 1. Furthermore, the learning device 101 and the reasoning device 121 can also exist on a cloud server.

[0168] In this embodiment, the case of using the learned model learned in the model generation unit 103 of the welding system 1 to output control parameters is described. However, it is also possible to obtain the learned model from external sources such as other welding systems and output control parameters based on the learned model.

[0169] Implementation Method 6

[0170] In this embodiment, a non-contact thermometer 7a measures the temperature of the electronic component mounted on the soldering surface of the substrate, and a non-contact displacement meter 6a measures the height of the electronic component mounted on the soldering surface of the substrate. The control device 9 determines, based on the measured temperature and height of the electronic component, whether the solder wettability of the electronic component has deteriorated, the electronic component has floated or tilted, or no electronic component is mounted on the substrate 10.

[0171] Figure 17 This is a diagram illustrating an example of temperature measurement using the non-contact thermometer 7a in Embodiment 6. Figure 18 This is a diagram showing an example of the measurement temperature of substrate 10 and the measurement temperature of a certain component A.

[0172] The temperature of the housing of the electronic component on the soldering surface rises due to heat transfer from the substrate 10, heat transfer from the soldering terminals of the electronic component, and the temperature inside the soldering apparatus.

[0173] Through the wetting and diffusion of the solder jet, the temperature of the soldering terminals and housing of electronic components rises. Therefore, as... Figure 18 As shown, even when the substrate temperature near the electronic component reaches a predetermined temperature, the temperature of the electronic component's casing will decrease if the solder wetting of the solder terminals of the electronic component is poor. By detecting this using the control device 9, the difference in the solder wetting state of the solder terminals of the electronic component can be extracted.

[0174] The control device 9 can also control the flow of flux, increase the preheating temperature, or increase the amount of flux applied when the temperature of the electronic components is low and the solder wettability is poor.

[0175] If the temperature of the electronic components is higher than the allowable range, the temperature inside the welding device may become too high, so the control device 9 checks the status of the exhaust device.

[0176] Sometimes, the soldering terminals of electronic components need to be cut to a specified length before soldering. If the soldering terminals are too long, they are more likely to come into contact with the solder jet, thus causing the temperature of the electronic component's casing to rise. If the soldering terminals are too short, they are less likely to come into contact with the solder jet, thus causing the temperature of the electronic component's casing to drop. The control device 9 can also utilize this characteristic to check the length of the soldering terminals of the electronic component based on the temperature of the electronic component's casing.

[0177] Furthermore, when an electronic component floats or tilts, the amount of protrusion of the soldering terminal onto the soldering surface of the substrate 10 decreases, resulting in poorer contact between the solder jet and the soldering terminal, and a lower temperature of the electronic component's casing. Therefore, the control device 9 can determine whether the electronic component has floated or tilted based on the temperature of the electronic component's casing.

[0178] When no electronic components are mounted on the substrate 10, since the temperature of the substrate is being measured, an abnormal value can be detected.

[0179] At this time, the height of the electronic component is measured by a non-contact displacement meter 6a, which has the following advantages.

[0180] The non-contact thermometer 7a alone cannot determine whether the problem lies in poor solder wetting of the solder terminals of the electronic component, whether the electronic component is floating or tilting, or whether the electronic component is not mounted on the substrate 10. When the height of the electronic component is measured by the non-contact displacement meter 6a, the control device 9 can determine that the problem is due to poor solder wetting of the solder terminals if the electronic component's height is normal and its temperature is low. Conversely, the control device 9 can determine that the electronic component is floating or tilting if its height is abnormal and its temperature is low.

[0181] The control device 9 can also determine the height of the electronic component based on the measured value of the non-contact displacement meter 6a and the height of the electronic component's housing. Alternatively, the control device 9 can also determine the height of the electronic component's housing based on the height of the substrate near the electronic component, and use that as the height of the electronic component.

[0182] When the electronic component is tilted, the amount of protrusion of the soldering terminal from the substrate 10 changes, and because of the tilt of the electronic component, the radiation state changes, thus changing the detected temperature of the component. Furthermore, the area where the temperature of the electronic component is detected shifts in the direction tilted relative to the reference area. Since the measurement result of the non-contact displacement gauge 6a also changes, it can be determined.

[0183] When an electronic component floats, the amount of protrusion of the soldering terminal from the substrate 10 decreases, thus changing the detected temperature rise of the electronic component. Simultaneously, the measured height of the electronic component relative to the substrate 10, as determined by the non-contact displacement gauge 6a, increases.

[0184] If there are no electronic components because they were forgotten to be mounted on the substrate 10, the substrate temperature is measured. If the substrate temperature becomes too high, the height of the electronic components relative to the substrate 10 measured by the non-contact displacement meter 6a will be the same as the height of the substrate 10. If the substrate temperature is too high and the height of the electronic components is the same as the height of the substrate 10, the control device 9 can determine that no electronic components are mounted on the substrate 10.

[0185] As a method for determining the status of electronic components mounted using the non-contact thermometer 7a, methods such as pattern matching of the shape of temperature contour lines, methods for calculating the deviation from normal data, methods for extracting the difference between normal data and symmetrical data, or AI-based methods such as deep learning can be used.

[0186] In the inspection of this embodiment, by using the measurement results of a non-contact thermometer 7a and a non-contact displacement meter 6a before welding, such as before welding, after welding, or after preheating, it is possible to check the wettability of the welding terminals, the floating or tilting of electronic components, and the presence or absence of electronic components with high precision.

[0187] Figure 19 This is a diagram showing the hardware structure of the control device 9.

[0188] The control device 9 can be configured to perform corresponding actions using either hardware or software digital circuitry. When the functions of the control device 9 are implemented using software, the control device 9 may, for example, be like... Figure 17 As shown, the device includes a processor 1002 and a memory 1003 connected via a bus 1001. The processor 1002 executes a program stored in the memory 1003.

[0189] Variations

[0190] (1) In Embodiment 1, the control device 9 adjusts the height of the solder jet generated by the jet nozzle based on the determination result of "board warping" during the soldering of the substrate 10, and then adjusts the height of the solder jet generated by the jet nozzle based on the determination result of "board temperature" during the soldering of the substrate 10. Here, in order to prevent the adjustment amount from becoming too large, the control device 9 may also consider the adjustment amount of the "solder jet height" based on the "board warping" during the soldering of the substrate 10, and adjust the "solder jet height" based on the "board temperature" during the soldering of the substrate 10.

[0191] That is, the control device 9 can also adjust the height of the solder jet generated by the jet nozzle by a first adjustment amount based on the determination result of the warping of the substrate 10 during the soldering of the substrate 10, and then adjust the height of the solder jet generated by the jet nozzle by a second adjustment amount based on the determination result of the temperature of the substrate 10 during the soldering of the substrate 10 and the first adjustment amount. That is, the larger the first adjustment amount is, the smaller the second adjustment amount is.

[0192] In addition, the control device 9 can also determine the adjustment amount of the solder jet height by simultaneously evaluating the "warping of the substrate" and the "temperature of the substrate" during the soldering of the substrate.

[0193] In addition, the control device 9 can also adjust the height of the solder jet based on either the warping of the substrate or the temperature of the substrate during the soldering process.

[0194] The embodiments disclosed herein should be considered exemplary in all respects and not restrictive. The scope of the invention is defined not by the foregoing description but by the claims, and is intended to include all modifications equivalent to and within the scope of the claims.

[0195] Label Explanation

[0196] 1: Welding system; 2: Conveying mechanism; 3: Flux coater; 4: Preheater; 5: Solder tank; 6, 6a, 6b, 6c: Non-contact displacement gauges; 7, 7a, 7b, 7c: Non-contact thermometers; 8: Substrate detection sensor; 9: Control device; 10: Substrate; 11: Flux; 13: Spray nozzle; 13a: Primary nozzle, 13b: Secondary nozzle; 14: Solder tank heater; 15: Spray motor; 16: Welding inspection device; 18: Flux coater control unit; 19: Solder spray height; 101: Learning device; 102, 122: Data acquisition unit; 103: Model generation unit; 111: Learned model storage device; 121: Inference device; 123: Inference unit; 1001: Bus; 1002: Processor; 1003: Memory.

Claims

1. A welding system comprising: A flux coating machine applies flux to a substrate; A preheater that preheats the substrate; Solder bath, used to store molten solder; A solder bath heater that melts the solder in the solder bath; A jet nozzle that sprays molten solder from the solder bath toward the substrate; The conveying mechanism sequentially conveys the substrate to the first position above the flux coating machine, the second position above the preheater, and the third position above the solder tank. A first non-contact displacement meter and a first non-contact thermometer are disposed above the jet nozzle; as well as The control device determines the warpage of the substrate during the soldering process based on the measurement results of the first non-contact displacement meter, and determines the temperature of the substrate during the soldering process based on the measurement results of the first non-contact thermometer. The control device adjusts the height of the solder jet generated by the jet nozzle based on the warping of the substrate during soldering and the temperature of the substrate.

2. The welding system according to claim 1, wherein, The control device determines the height of the jet nozzle based on the measurement result of the first non-contact displacement meter when no solder is being ejected from the jet nozzle, and adjusts the height of the jet nozzle according to the determined height.

3. The welding system according to claim 2, wherein, The control device determines the height of the solder jet generated by the jet nozzle based on the measurement result of the first non-contact displacement meter in the state before the solder is sprayed from the jet nozzle and before the soldering of the substrate is performed, and adjusts the height of the solder jet based on the determined height of the solder jet.

4. The welding system according to any one of claims 1 to 3, wherein, The welding system includes a second non-contact displacement meter and a second non-contact thermometer disposed above the region between the second position and the third position. The control device determines the warpage of the substrate after it has been preheated by the preheater and before it has been soldered, based on the measurement results of the second non-contact displacement meter, and determines the temperature of the substrate after it has been preheated and before it has been soldered, based on the measurement results of the second non-contact thermometer.

5. The welding system according to claim 4, wherein, The control device adjusts the temperature of the preheater and the height of the solder jet generated by the jet nozzle based on the warping of the substrate after it is preheated and before it is soldered, and the temperature of the substrate.

6. The welding system according to any one of claims 1 to 5, wherein, The welding system includes a third non-contact displacement gauge positioned above the region between the first position and the second position. The control device determines, based on the measurement results of the third non-contact displacement meter, whether the components disposed on the substrate float off the substrate after the flux coating machine applies flux to the substrate.

7. The welding system according to any one of claims 1 to 6, wherein, The welding system includes a third non-contact thermometer positioned above the area between the first position and the second position. The control device determines the temperature of the substrate after the flux coating machine applies flux to the substrate based on the measurement result of the third non-contact thermometer.

8. The welding system according to claim 7, wherein, The control device estimates the amount of flux applied to the substrate based on the temperature of the substrate after flux has been applied.

9. The welding system according to any one of claims 1 to 8, wherein, After being transported to the fourth position, the substrate is transported to the first position via the transport mechanism. The welding system includes a fourth non-contact displacement meter and a fourth non-contact thermometer disposed above the fourth position. The control device determines the warpage of the substrate before flux is applied based on the measurement results of the fourth non-contact displacement meter, and determines the temperature of the substrate before flux is applied based on the measurement results of the fourth non-contact thermometer.

10. The welding system according to claim 9, wherein, The control device adjusts the temperature of the preheater and the height of the solder jet based on the warpage of the substrate before flux is applied and the temperature of the substrate.

11. The welding system according to claim 3, wherein, The control device generates data representing the relationship between the height of the jet nozzle before adjustment, the height of the solder jet before adjustment, the warping of the substrate during welding, and the temperature of the substrate during welding and the welding defect rate.

12. The welding system according to claim 3, wherein, The control device includes a learning device. The learning device includes: The data acquisition unit acquires learning data including the height of the jet nozzle before adjustment, the height of the solder jet before adjustment, the warping of the substrate during the welding of the substrate, the temperature of the substrate during the welding of the substrate, and the control parameters of the welding system. as well as The model generation unit uses the learning data to generate a learned model, which estimates the control parameters of the welding system based on the height of the jet nozzle before adjustment, the height of the solder jet before adjustment, the warpage of the substrate during welding, and the temperature of the substrate during welding.

13. The welding system according to claim 3, wherein, The control device includes a reasoning device. The reasoning device includes: The data acquisition unit acquires the height of the jet nozzle before adjustment, the height of the solder jet before adjustment, the warpage of the substrate during the soldering of the substrate, and the temperature of the substrate during the soldering of the substrate. as well as The inference unit uses a learned model to infer the control parameters of the welding system based on the height of the jet nozzle before adjustment, the height of the solder jet before adjustment, the warpage of the substrate during welding, and the temperature of the substrate during welding. Based on the height of the jet nozzle before adjustment, the height of the solder jet before adjustment, the warpage of the substrate during welding, and the temperature of the substrate during welding, which are input from the data acquisition unit, the inference unit outputs the control parameters of the welding system.

14. The welding system according to claim 12 or 13, wherein, The control parameters of the welding system include the flux application amount of the flux coating machine, the temperature of the preheater, the height of the solder jet generated by the jet nozzle, and the temperature of the solder.

15. The welding system according to claim 4, wherein, The second non-contact thermometer measures the temperature of the electronic components mounted on the soldered surface of the substrate. The second non-contact displacement gauge measures the height of the electronic component. The control device determines, based on the temperature and height of the electronic component, whether the solder wettability of the electronic component has deteriorated, the electronic component has floated or tilted, or the electronic component is not mounted on the substrate.

16. The welding system according to claim 1, wherein, The control device uses the warping of the substrate and the temperature of the substrate during the soldering process to determine whether the soldering result is good or bad.

17. The welding system according to claim 1, wherein, The control device adjusts the height of the solder jet generated by the jet nozzle by a first adjustment amount based on the determination result of the warping of the substrate during the soldering of the substrate. Then, based on the determination result of the temperature of the substrate during the soldering of the substrate and the first adjustment amount, the control device adjusts the height of the solder jet generated by the jet nozzle by a second adjustment amount.

18. A welding method, comprising a welding system including a flux applicator, a preheater, a solder bath, a jet nozzle, a conveying mechanism, a first non-contact displacement meter, a first non-contact thermometer, and a control device, wherein the first non-contact displacement meter and the first non-contact thermometer are disposed above the jet nozzle, the welding method comprising: In the coating step, the flux coating machine applies flux to the substrate; In the preheating step, the preheater preheats the substrate; In the spraying step, the spray nozzle sprays molten solder from the solder bath toward the substrate; In the conveying step, the conveying mechanism sequentially conveys the substrate to the first position above the flux coating machine, the second position above the preheater, and the third position above the solder tank. In the determination step, the control device determines the warping of the substrate during the welding of the substrate based on the measurement result of the first non-contact displacement meter during the welding of the substrate, and determines the temperature of the substrate during the welding of the substrate based on the measurement result of the first non-contact thermometer during the welding of the substrate. as well as In the adjustment step, the control device adjusts the height of the solder jet generated by the jet nozzle based on the warping of the substrate during soldering and the temperature of the substrate.

19. A welding system comprising: A flux coating machine applies flux to a substrate; A preheater that preheats the substrate; Solder bath, used to store molten solder; A solder bath heater that melts the solder in the solder bath; A jet nozzle that sprays molten solder from the solder bath toward the substrate; The conveying mechanism sequentially conveys the substrate to the first position above the flux coating machine, the second position above the preheater, and the third position above the solder tank. A first non-contact displacement meter and a first non-contact thermometer are disposed above the jet nozzle; as well as The control device determines the warpage of the substrate during the soldering process based on the measurement results of the first non-contact displacement meter, and determines the temperature of the substrate during the soldering process based on the measurement results of the first non-contact thermometer. The control device adjusts the flux application amount of the flux coating machine based on the warping of the substrate during soldering and the temperature of the substrate.

20. A welding system comprising: A flux coating machine applies flux to a substrate; A preheater that preheats the substrate; Solder bath, used to store molten solder; A solder bath heater that melts the solder in the solder bath; A jet nozzle that sprays molten solder from the solder bath toward the substrate; The conveying mechanism sequentially conveys the substrate to the first position above the flux coating machine, the second position above the preheater, and the third position above the solder tank. A first non-contact displacement meter and a first non-contact thermometer are disposed above the jet nozzle; as well as The control device determines the warpage of the substrate during the soldering process based on the measurement results of the first non-contact displacement meter, and determines the temperature of the substrate during the soldering process based on the measurement results of the first non-contact thermometer. The control device adjusts the temperature of the preheater based on the warping of the substrate during welding and the temperature of the substrate.

21. A welding system comprising: A flux coating machine applies flux to a substrate; A preheater that preheats the substrate; Solder bath, used to store molten solder; A solder bath heater that melts the solder in the solder bath; A jet nozzle that sprays molten solder from the solder bath toward the substrate; The conveying mechanism sequentially conveys the substrate to the first position above the flux coating machine, the second position above the preheater, and the third position above the solder tank. A first non-contact displacement meter and a first non-contact thermometer are disposed above the jet nozzle; as well as The control device determines the warpage of the substrate during the soldering process based on the measurement results of the first non-contact displacement meter, and determines the temperature of the substrate during the soldering process based on the measurement results of the first non-contact thermometer. The control device adjusts the temperature of the solder based on the warping of the substrate during soldering and the temperature of the substrate.

22. A welding method, comprising a welding system including a flux applicator, a preheater, a solder bath, a jet nozzle, a conveying mechanism, a first non-contact displacement meter, a first non-contact thermometer, and a control device, wherein the first non-contact displacement meter and the first non-contact thermometer are disposed above the jet nozzle, the welding method comprising: In the coating step, the flux coating machine applies flux to the substrate; In the preheating step, the preheater preheats the substrate; In the spraying step, the spray nozzle sprays molten solder from the solder bath toward the substrate; In the conveying step, the conveying mechanism sequentially conveys the substrate to the first position above the flux coating machine, the second position above the preheater, and the third position above the solder tank. In the determination step, the control device determines the warping of the substrate during the welding of the substrate based on the measurement result of the first non-contact displacement meter during the welding of the substrate, and determines the temperature of the substrate during the welding of the substrate based on the measurement result of the first non-contact thermometer during the welding of the substrate. as well as In the adjustment step, the control device adjusts the flux application amount of the flux coating machine according to the warping of the substrate during soldering and the temperature of the substrate.

23. A welding method, comprising a welding system including a flux applicator, a preheater, a solder bath, a jet nozzle, a conveying mechanism, a first non-contact displacement meter, a first non-contact thermometer, and a control device, wherein the first non-contact displacement meter and the first non-contact thermometer are disposed above the jet nozzle, the welding method comprising: In the coating step, the flux coating machine applies flux to the substrate; In the preheating step, the preheater preheats the substrate; In the spraying step, the spray nozzle sprays molten solder from the solder bath toward the substrate; In the conveying step, the conveying mechanism sequentially conveys the substrate to the first position above the flux coating machine, the second position above the preheater, and the third position above the solder tank. In the determination step, the control device determines the warping of the substrate during the welding of the substrate based on the measurement result of the first non-contact displacement meter during the welding of the substrate, and determines the temperature of the substrate during the welding of the substrate based on the measurement result of the first non-contact thermometer during the welding of the substrate. as well as In the adjustment step, the control device adjusts the temperature of the preheater based on the warping of the substrate during the soldering of the substrate and the temperature of the substrate.

24. A welding method, comprising a welding system including a flux applicator, a preheater, a solder bath, a jet nozzle, a conveying mechanism, a first non-contact displacement meter, a first non-contact thermometer, and a control device, wherein the first non-contact displacement meter and the first non-contact thermometer are disposed above the jet nozzle, the welding method comprising: In the coating step, the flux coating machine applies flux to the substrate; In the preheating step, the preheater preheats the substrate; In the spraying step, the spray nozzle sprays molten solder from the solder bath toward the substrate; In the conveying step, the conveying mechanism sequentially conveys the substrate to the first position above the flux coating machine, the second position above the preheater, and the third position above the solder tank. In the determination step, the control device determines the warping of the substrate during the welding of the substrate based on the measurement result of the first non-contact displacement meter during the welding of the substrate, and determines the temperature of the substrate during the welding of the substrate based on the measurement result of the first non-contact thermometer during the welding of the substrate. as well as In the adjustment step, the control device adjusts the temperature of the solder based on the warping of the substrate during soldering and the temperature of the substrate.

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