Reflow apparatus

Abstract

The present invention provides a reflow apparatus capable of detecting when the amount of flux recovered has reached a predetermined level. [Solution] The reflow apparatus comprises a furnace body, a transport unit for transporting the object to be heated within the furnace body, a flux recovery device for sucking out the atmospheric gas inside the furnace body with a blower and recovering the flux contained in the atmospheric gas, and a control device for detecting when the amount of flux recovered has reached a predetermined amount based on the torque change of the blower motor.

Description

Technical Field

[0001] The present invention relates to a reflow apparatus provided with a flux recovery device.

Background Art

[0002] In recent years, reflow apparatuses are widely known as apparatuses for mounting electronic components on a substrate. In a reflow apparatus, when soldering the electrodes of a substrate and an electronic component, the flux in the solder paste volatilizes in the furnace body. The volatilized flux is likely to adhere and deposit particularly in a location with a low temperature in the furnace body, and the adhered flux may cause problems such as falling onto the substrate. Further, the flux also tends to accumulate near the fan motor in each zone of the reflow apparatus. For this reason, it has been proposed to mount a flux recovery device for recovering the flux volatilized in the furnace body on the reflow apparatus (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a conventional reflow apparatus, it is difficult to grasp how much flux is recovered by the flux recovery device. For this reason, in a conventional reflow apparatus, it is difficult to know when maintenance of the flux recovery device should be performed. Further, depending on the amount of flux recovered, there is also a risk that the inverter controlling the flux recovery device trips.

[0005] An object of the present invention is to provide a reflow apparatus capable of detecting that the flux recovery amount has reached a predetermined amount.

Means for Solving the Problems

[0006] To solve the above-mentioned problems, the present invention provides: The furnace body and A transport unit that transports the object to be heated within the furnace body, A flux recovery device that uses a blower to draw in the atmospheric gas inside the furnace and recovers the flux contained in the atmospheric gas, A control device that detects when the amount of flux recovered has reached a predetermined amount based on the torque change of the blower motor. This is a reflow apparatus equipped with [specific features / features]. [Effects of the Invention]

[0007] According to at least one embodiment, it is possible to detect that the amount of flux recovered has reached a predetermined amount based on the torque change of the blower motor. The effects described herein are not necessarily limited, and any of the effects described herein may be used. Furthermore, the effects illustrated in the following description should not be interpreted as limiting the scope of the present invention. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing a reflow apparatus according to one embodiment of the present invention. [Figure 2] Figure 2 is a graph showing an example of a temperature profile during reflow. [Figure 3] Figure 3 is a schematic cross-sectional view showing the configuration of the flux recovery device. [Figure 4] Figure 4 is a block diagram showing the configuration of the control system for a reflow machine. [Figure 5] Figure 5 is a graph showing an example of the change in the motor's torque value with respect to the motor's operating time. [Figure 6] Figure 6 is a flowchart illustrating the operation of the control system for the flux recovery device. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below. The description will be given in the following order. <1. One Embodiment> <2. Variant> The embodiment described below is a preferred example of the present invention and is subject to various technically preferred limitations. However, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

[0010] <1. One Embodiment> [Configuration of the reflow apparatus 101] Figure 1 shows a schematic configuration of a reflow apparatus 101 according to one embodiment of the present invention. The reflow apparatus 101 comprises a reflow oven 102 as a heating device, a transport chain 103 as a transport means for transporting a workpiece, such as a printed circuit board (hereinafter referred to as "workpiece") W on which surface-mount electronic components and solder are mounted on both sides of a printed wiring board, within the reflow oven 102, rotating bodies (idlers, sprockets, etc.) 104a, 104b, 104c, 104d that define the movement path of the transport chain 103, and an outer plate 105. Note that in Figure 1, only one of the two parallel transport chains 103 is shown.

[0011] The reflow oven 102 heats the workpiece W from above and below, and then cools it after heating. The conveyor chain 103 is one of two conveyor chains arranged parallel to the conveying direction. For example, a roller chain is used as the conveyor chain 103. The outer plate 105 is a case that covers the entire unit.

[0012] After the workpiece W is loaded into the reflow oven 102 from the inlet 106, it is transported by the conveyor chain 103 at a predetermined speed in the direction of the arrow (from left to right in Figure 1) and finally removed from the outlet 107. Although not shown, a workpiece loading device for loading the workpiece W is provided before the inlet 106, and a workpiece unloading device for sending the workpiece W to the outside is provided after the outlet 107.

[0013] Along the transport path from the inlet 106 to the outlet 107, the reflow oven 102 is sequentially divided into, for example, nine zones Z1 to Z9, and these zones Z1 to Z9 are arranged in line. The seven zones Z1 to Z7 from the inlet 106 side are heating zones, and the two zones Z8 and Z9 from the outlet 107 side are cooling zones. Forced cooling units (not shown) are provided in relation to zones Z8 and Z9. Note that the number of zones is just an example, and other numbers of zones may be arranged.

[0014] The reflow oven 102 has a furnace body 10. Heating chambers 102a are partitioned into zones Z1 to Z7 of the furnace body 10. Cooling chambers 102b are partitioned into zones Z8 and Z9 of the furnace body 10.

[0015] The heating chambers 102a in the multiple zones Z1 to Z7, and the cooling chambers 102b in zones Z8 and Z9, as described above, control the temperature of the workpiece W according to the temperature profile during reflow. Figure 2 shows a schematic example of a temperature profile. The horizontal axis represents time, and the vertical axis represents the surface temperature of the workpiece W. The first section is the heating section R1 where the temperature rises due to heating, the next section is the preheating section R2 where the temperature remains almost constant, the next section is the reflow (main heating) section R3, and the last section is the cooling section R4.

[0016] The heating section R1 is the period during which the workpiece W is heated from room temperature to the preheating section R2 (e.g., 150°C to 170°C). The preheating section R2 is a period during which isothermal heating is performed to activate the flux, remove the oxide film on the surface of the electrodes and solder powder, and eliminate uneven heating of the workpiece W. The reflow section R3 (e.g., peak temperature of 220°C to 240°C) is the period during which the solder melts and the bonding is completed. Even after passing through the preheating section R2, uneven temperature rise may still exist, so in the reflow section R3, it is necessary to raise the temperature to a level exceeding the solder melting point. The final cooling section R4 is a period during which the workpiece W is rapidly cooled and the solder composition is formed. In the case of lead-free solder, the temperature in the reflow section R3 will be higher (e.g., 240°C to 260°C).

[0017] In Figure 2, curve 1 shows an example of the temperature profile for lead-free solder. An example of the temperature profile for Sn-Pb eutectic solder is shown by curve 2. Since the melting point of lead-free solder is higher than that of eutectic solder, the set temperatures in the preheat section R2 and reflow section R3 for lead-free solder are set higher than those for eutectic solder.

[0018] In the reflow apparatus 101 shown in Figure 1, zones Z1 and Z2 are primarily responsible for controlling the temperature of the heating section R1 in Figure 2. Zones Z3, Z4, and Z5 are primarily responsible for controlling the temperature of the preheating section R2. Zones Z6 and Z7 are responsible for controlling the temperature of the reflow section R3. Zones Z8 and Z9 are responsible for controlling the temperature of the cooling section R4.

[0019] During reflow, the furnace body 10 is filled with an atmospheric gas. The atmospheric gas includes, for example, nitrogen (N2) and flux. Inside the furnace body 10, hot air (heated nitrogen gas) is blown onto the workpiece W, heating the workpiece W. Infrared radiation may also be irradiated along with the hot air.

[0020] The flux recovery unit 20 is connected to the heating chamber 102a of zone 7 via piping 11 and piping 12. The number of flux recovery units 20 provided in the reflow apparatus 101 and the zones to which the flux recovery units 20 are connected are not limited to this example. Furthermore, the chamber to which the flux recovery unit 20 is connected is not limited to the heating chamber 102a, but may also be the cooling chamber 102b.

[0021] In one embodiment, the flux recovery device 20 is a water-cooled flux recovery device. The flux recovery device 20 draws in the atmospheric gas in the heating chamber 102a via the piping 11 and cools this atmospheric gas to separate and recover the flux from the atmospheric gas. The flux recovery device 20 also supplies the atmospheric gas from which the flux has been removed to the heating chamber 102a via the piping 12.

[0022] Figure 3 shows the configuration of the flux recovery device 20. The flux recovery device 20 includes a case 21, a cooling device 22, and a blower 23.

[0023] Case 21 has a box shape. The inside of Case 21 is divided into a flux recovery chamber 211 and a fan chamber 212. Piping 11 is connected to the flux recovery chamber 211, and piping 12 is connected to the fan chamber 212. The atmospheric gas drawn in from the heating chamber 102a passes sequentially through piping 11, the flux recovery chamber 211, the fan chamber 212, and piping 12, and is then blown back into the heating chamber 102a.

[0024] The flux recovery chamber 211 contains the flux that has been liquefied by cooling. A flux recovery container (not shown) for containing the liquefied flux may be placed inside the flux recovery chamber 211. The flux recovery container may be configured to be removable from inside the flux recovery chamber 211.

[0025] The cooling device 22 is located inside the flux recovery chamber 211. The cooling device 22 cools the atmospheric gas flowing into the flux recovery chamber 211 via the piping 11, thereby liquefying the flux in the atmospheric gas on the inner surface of the flux recovery chamber 211 or on the surface of the cooling device 22. This allows the flux to be separated from the atmospheric gas. The cooling device 22 is, for example, a radiator composed of cooling water pipes and fins.

[0026] Blower 23 draws atmospheric gas from heating chamber 102a via piping 11 and blows the atmospheric gas, from which flux has been removed by cooling, back into heating chamber 102a via piping 12. Blower 23 includes a fan 231 and a motor 232. Fan 231 is rotationally driven by motor 232. Fan 231 is located within fan chamber 212. Piping 12 is located to the side of fan 231. Motor 232 rotates fan 231. Motor 232 is fixed to the outer surface of case 21.

[0027] [Configuration of control system 30] The reflow apparatus 101 further comprises a control system 30 that controls the reflow apparatus 101. Figure 4 shows the configuration of the control system 30. The control system 30 comprises an inverter 31, a programmable logic controller (hereinafter referred to as "PLC") 32, a personal computer (hereinafter referred to as "PC") 33, and equipment 34 such as alarms and indicator lights. Here, indicator lights also include signal lights and rotating lights. Note that in Figure 4, only the control block of the flux recovery device 20 is shown, and the control blocks of the reflow oven 102 and the rotating bodies 104a, 104b, 104c, 104d are omitted.

[0028] PC33 is connected to PLC32. Inverter31 is connected to PLC32. Devices 34 such as alarms and indicator lights are connected to PLC32. Motor232 is connected to inverter31.

[0029] PC33 functions as a user interface. PC33 controls the inverter 31 via PLC32. PC33 receives detection signals from the inverter 31 via PLC32 and displays an alarm screen or the like according to the received detection signals. PLC32 controls the inverter 31 and other components according to commands from PC33. Depending on the detection signals received from the inverter 31, PLC32 may output a warning sound from an alarm device or illuminate an indicator light.

[0030] The inverter 31 controls the drive of the motor 232 at a predetermined command frequency based on the control signal from the PLC 32. The inverter 31 calculates the torque value of the motor 232 from the motor information received from the motor 232. The inverter 31 detects from the calculated torque value of the motor 232 that the amount of flux recovered in the flux recovery device 20 has reached a predetermined amount. In one embodiment, an example will be described in which the inverter 31 is a control device that detects the amount of flux recovered.

[0031] More specifically, the inverter 31 detects that the flux recovery amount in the flux recovery device 20 has reached a predetermined amount by the following two detection methods (1) and (2). (1) Immediately after driving the blower 23, the inverter 31 detects the maximum torque value τ max (see FIG. 5) of the motor 232, and based on whether this maximum torque value τ max exceeds the threshold value τ α , it detects that the flux recovery amount in the flux recovery device 20 has reached a predetermined amount. Specifically, when the maximum torque value τ max exceeds the threshold value τ α , the inverter 31 determines that the flux recovery amount in the flux recovery device 20 has reached a predetermined amount. On the other hand, when the maximum torque value τ max does not exceed the threshold value τ α , the inverter 31 determines that the flux recovery amount in the flux recovery device 20 has not reached a predetermined amount. The threshold value τ α is stored in advance in the memory within the inverter 31. To prevent misdetection of the maximum torque value τ max , the inverter 31 performs the detection of the maximum torque value τ max after a lapse of a predetermined time T from the start of driving the blower 23. This predetermined time T is also stored in advance in the memory within the inverter 31. (2) The inverter 31 calculates the change amount of the torque value of the motor 232, and based on this change amount of the torque value, it detects that the flux recovery amount in the flux recovery device 20 has reached a predetermined amount.

[0032] The predetermined amount in the flux recovery amount represents the recovery amount at which the fan 231 contacts the liquid surface of the flux, or the recovery amount at which a part of the fan 231 (for example, a part of the part less than half of the fan 231) is immersed in the flux.

[0033] The above detection method (2) can be further divided into the following two detection methods (2-1) and (2-2). (2-1) Immediately after the blower 23 is driven, the inverter 31 uses the torque value that decreases with the time the blower 23 is driven to calculate the torque change amount of the blower 23 motor 232 (torque decrease amount Δτ with the time the blower 23 is driven). 21 (See Figure 5) is calculated. Then, the inverter 31 calculates the calculated torque change amount Δτ. 21 Based on this, it is detected that the amount of flux recovered in the flux recovery device 20 has reached a predetermined amount. (2-2) The inverter 31 calculates the torque change amount of the blower 23 motor 232 (torque increase amount due to the operation time of the blower 23) using the torque value that increases with the operation time of the blower 23 during a predetermined period after the start of operation of the blower 23. Based on the calculated torque change amount, the inverter 31 detects that the flux recovery device 20 has reached a predetermined amount.

[0034] In one embodiment, "immediately after the blower 23 is driven" refers to, for example, the period from the start of operation of the reflow apparatus 101 until the point in time when the time change of the torque value changes from decreasing to increasing. Also, "the period after a predetermined time has elapsed since the blower 23 was driven" refers to, for example, the period from the point in time when the time change of the torque value changes from decreasing to increasing.

[0035] The following explains how the above-mentioned method for detecting the amount of flux recovered (2-1) was discovered. As the amount of flux recovered in the flux recovery chamber 211 increases, the flux level rises, and the fan 231 may come into contact with or be immersed in the flux. When the fan 231 is in contact with or immersed in the flux, it is normally assumed that the torque value of the motor 232 will remain high when the fan 231 is driven by the motor 232. However, the inventors have investigated this through experiments and found that when the fan 231 is in contact with or immersed in the flux and the fan 231 is driven by the motor 232, the torque value of the motor 232 temporarily increases immediately after the fan 231 is driven, and then tends to gradually decrease. Furthermore, it was found that this decrease in torque value tends to increase the more the fan 231 is immersed in the flux. This tendency is thought to be caused by the high-speed rotating fan 231 flicking the flux away immediately after it is driven.

[0036] Therefore, the inventors diligently investigated a method for detecting when the amount of flux recovered has reached a predetermined amount by utilizing the tendency for the torque value of the motor 232 to decrease immediately after the fan 231 is driven (i.e., immediately after the blower 23 is driven). As a result, they discovered the above-mentioned method for detecting the amount of flux recovered (2-1).

[0037] Preferably, the inverter 31 has a filter and performs filtering on the torque value of the motor 232. This suppresses fluctuations in the torque value and improves the accuracy of detecting the flux recovery amount. Examples of filters include first-order lag filters such as low-pass filters.

[0038] [Operation of the reflow machine 101] The following describes examples of the operation of the reflow apparatus 101 corresponding to the above-described flux recovery amount detection methods (2-1) and (2-2) with reference to Figures 5 and 6. Figure 5 shows an example of torque value change corresponding to steps S11 to S18 in Figure 6.

[0039] In step S11, when the operator commands the PC 33 to start the reflow apparatus 101, the PLC 32 controls each part of the reflow apparatus 101 based on the command from the PC 33 and starts the operation of the reflow apparatus 101. That is, the inverter 31 starts the operation of the flux recovery device 20. Next, in step S12, the inverter 31 determines the number of times the flux recovery amount has been detected (number of times it has not been detected) n.

[0040] If it is determined in step S12 that the number of detections n for the amount of flux recovered is 0, then in step S13 the inverter 31 detects the frequency stability of the motor 32, and a predetermined time T from the detection time T0 of that frequency stability A Wait for [s]. Here, a predetermined time T A [s] is the time required for the torque value of the motor 32 to stabilize, and is pre-stored in the memory of the inverter 31.

[0041] Next, in step S14, the inverter 31 operates for a predetermined time T A [s] After waiting time T1, a stable torque value τ1 is obtained and stored in the memory of the inverter 31. Next, in step S15, the inverter 31 waits for a predetermined time T from the time T1 when the stable torque value τ1 was obtained. B Wait for [s]. Here, a predetermined time T B [s] is the time required for the change (decrease) in the torque value to become significant, and is pre-stored in the memory of the inverter 31.

[0042] Next, in step S16, the inverter 31 operates for a predetermined time T B At time T2 after waiting for [s], the torque value τ2 is obtained, and the difference (torque change) Δτ between the torque value τ2 at time T2 and the torque value τ1 at time T1 is calculated. 21 (=τ2-τ1) is calculated. In one embodiment, time T BAn example of obtaining the torque value will be described, but the torque value may also be obtained after a predetermined time ΔT has elapsed from time T2 (i.e., at time T2+ΔT). Next, in step S17, the inverter 31 controls the difference Δτ 21 The threshold Δτ a Smaller (Δτ) 21 <Δτ a Determine whether or not it is true.

[0043] thresholdΔτ a This is pre-stored in the memory within the inverter 31. Threshold Δτ a This is set in advance, for example, as follows: Water is placed in the flux recovery device 20 as a substitute for flux and set to a predetermined water level. At this predetermined water level, the above difference Δτ 21 The difference Δτ is calculated using the same procedure as the previous calculation, and the threshold Δτ a The predetermined water level is preferably set to correspond to the liquid level of the flux requiring maintenance of the flux recovery device 20.

[0044] Step S17: Difference Δτ 21 The threshold Δτ a Smaller (Δτ) 21 <Δτ a If it is determined that the flux recovery device 20 has reached a predetermined amount, then in step S18, the inverter 31 detects that the amount of flux recovered by the flux recovery device 20 has reached a predetermined amount, that is, that the flux recovery device 20 is due for maintenance. Next, in step S19, the inverter 31 transmits a detection signal to the PC 33 via the PLC 32. Upon receiving the detection signal, the PC 33 displays a warning screen on its monitor indicating that the flux recovery device 20 is due for maintenance. Note that the method of warning the operator is not limited to a screen display; for example, the PLC 32, upon receiving the detection signal from the inverter 31, may output a warning sound from an alarm or illuminate an indicator light. Next, in step S20, the inverter 31 continues to operate the flux recovery device 20.

[0045] Step S17: Difference Δτ 21 The threshold Δτa Not smaller (Δτ 21 ≥Δτ a If it is determined that the flux recovery amount in the flux recovery device 20 has not reached a predetermined amount, i.e., the flux recovery device 20 is operating normally, the inverter 31 detects this and returns to step S12.

[0046] If, in step S12, it is determined that the number of detections n for the amount of flux recovered is greater than 0, then in step S22, the inverter 31 obtains a stable torque value τ3 at time T3 and stores it in the memory of the inverter 31. Time T3 is selected from the time period in which the torque value tends to increase as the operating time of the blower 23 elapses. Time T3 is pre-stored in the memory of the inverter 31. Alternatively, the inverter 31 may detect an increase in the torque value as the operating time of the blower 23 elapses and store the time after such detection as time T3 in the memory.

[0047] Next, in step S23, the inverter 31 starts from the time T3 when a stable torque value τ3 is acquired for a predetermined time T C Wait for [s]. Here, a predetermined time T C [s] is the time required for the change (increase) in the torque value to become significant, and is pre-stored in the memory of the inverter 31.

[0048] Next, in step S24, the inverter 31 operates for a predetermined time T C [s] After waiting, the torque value τ4 is obtained at time T4, and the difference (torque change) Δτ is calculated between the torque value τ4 at time T4 and the torque value τ3 at time T3. 43 (=τ4-τ3) is calculated. In one embodiment, an example of detecting the torque value at time T4 is described, but the torque value may be obtained after a predetermined time ΔT has elapsed from time T4 (i.e., at time T4+ΔT). Next, in step S24, the inverter 31 calculates the difference Δτ 43 The threshold Δτ b Larger (Δτ) 43 >Δτ bDetermine whether or not it is true. Threshold Δτ b This is pre-stored in the memory within the inverter 31. Threshold Δτ b For example, the threshold Δτ a Similarly, the threshold Δτ can be set by using water as a substitute for flux and measuring the torque value. b The threshold Δτ a It may be equal to the absolute value of the threshold Δτ. a It may be different from the absolute value of .

[0049] Step S25: Difference Δτ 43 (=τ4-τ3) is the threshold Δτ b Larger (Δτ) 43 >Δτ b If it is determined that the flux recovery device 20 has reached a predetermined amount, then in step S26, the inverter 31 detects that the amount of flux recovered by the flux recovery device 20 has reached a predetermined amount, that is, that the flux recovery device 20 is due for maintenance. Next, in step S27, the inverter 31 transmits a detection signal to the PC 33 via the PLC 32. Upon receiving the detection signal, the PC 33 displays a warning screen on its monitor indicating that the flux recovery device 20 is due for maintenance. Note that the method of warning the operator is not limited to a screen display as described above, but may also include a warning sound from an alarm or the illumination of an indicator light. Next, in step S20, the inverter 31 continues to operate the flux recovery device 20.

[0050] Step S25: Difference Δτ 43 The threshold Δτ b Not larger (Δτ 43 ≤Δτ b If it is determined that the flux recovery amount in the flux recovery device 20 has not reached a predetermined amount, i.e., the flux recovery device 20 is operating normally, the inverter 31 detects this and returns the process to step S22.

[0051] [Effects and Effects] According to the embodiment of the present invention described above, the inverter 31, as a control device, controls the torque change amount Δτ immediately after the blower 23 is driven. 21 Based on (=τ2-τ1) (see Figure 5), the system detects whether the amount of flux recovered in the flux recovery device 20 has reached a predetermined amount. If it is detected that the amount of flux recovered has reached a predetermined amount, the PC 33 receives a detection signal from the inverter 31 via the PLC 32 and displays an alarm screen or the like according to the received detection signal. The PLC 32 may also output a warning sound from the alarm or illuminate an indicator light according to the detection signal received from the inverter 31. As a result, the operator can know that the amount of liquefied flux recovered has reached a predetermined amount. Specifically, for example, the operator can know that the amount of liquefied flux recovered has reached a point where the fan 231 is in contact with or submerged in the liquid surface of the liquefied flux. Therefore, the operator can know that the flux recovery device 20 is due for maintenance before the inverter 31 trips. Furthermore, since maintenance of the flux recovery device 20 can be performed before the inverter 31 trips, failure of the motor 232 can also be prevented.

[0052] The inverter 31 will remain in place for a predetermined time T until the torque value of the motor 32 stabilizes. A [s] The torque value τ1 obtained after waiting, and a predetermined time T until the amount of change (decrease) in the torque value becomes significant. B [s] Using the torque value τ2 obtained after waiting, the difference Δτ 21 (=τ2-τ1) is calculated. Then, the inverter 31 calculates the difference Δτ 21 Based on this, it is detected when the amount of liquefied flux recovered reaches a predetermined amount. Therefore, the amount of flux recovered can be detected reliably.

[0053] <2. Variant> In one embodiment, an example was described in which the flux recovery device 20 is water-cooled. However, the flux recovery device 20 is not limited to water cooling and can use various types. For example, air cooling, pressurized compression, or inertial dust collection methods can be used.

[0054] In one embodiment, an example was described in which the flux recovery device 20 is connected to either the heating chamber 102a or the cooling chamber 102b. However, the chamber to which the flux recovery device 20 is connected is not limited to the heating chamber 102a or the cooling chamber 102b, and the flux recovery device 20 may also be connected to a buffer chamber. The buffer chamber may be provided, for example, on the inlet side of the reflow apparatus 101, between adjacent heating chambers 102a, between adjacent cooling chambers 102b, or between adjacent heating chambers 102a and cooling chambers 102b.

[0055] In one embodiment, an example was described in which pipes 11 and 12 are connected to the same heating chamber 102a. However, the connection locations of pipes 11 and 12 are not limited to this example; for example, pipes 11 and 12 may be connected to different heating chambers 102a. Similarly, pipes 11 and 12 may be connected to different cooling chambers 102b.

[0056] In one embodiment, an example was described in which the inverter 31 performs processing corresponding to both of the two detection methods (1) and (2). However, the inverter 31 may perform processing corresponding to only one of the two detection methods (1) and (2). Alternatively, the inverter 31 may perform processing corresponding to only one of the two detection methods (2-1) and (2-2).

[0057] In one embodiment, the inverter 31 detects the maximum torque value τ immediately after the blower 23 is driven as a detection method (1). max is threshold τ α An example has been described in which the flux recovery amount in the flux recovery device 20 is detected as having reached a predetermined amount based on whether or not it exceeds a certain threshold. However, the inverter 31 may also detect that the flux recovery amount has reached a predetermined amount by a method other than detection method (1). For example, immediately after the blower 23 is driven, the inverter 31 detects that the torque value acquired at a predetermined cycle exceeds the threshold τ. βThe flux recovery device 20 may detect whether the amount of flux recovered has reached a predetermined amount by determining whether it exceeds a certain threshold τ. Specifically, the inverter 31 determines whether the torque value acquired at a predetermined cycle immediately after the blower 23 is driven is a threshold τ. β If it exceeds this value, it may be determined that the amount of flux recovered in the flux recovery device 20 has reached a predetermined amount. On the other hand, the inverter 31 uses the torque value acquired at a predetermined cycle as a threshold τ. β If it does not exceed the threshold τ, it may be determined that the amount of flux recovered in the flux recovery device 20 has not reached the predetermined amount. β This may be pre-stored in the memory of the inverter 31.

[0058] In one embodiment, an example was described in which the inverter 31 is a control device that detects the amount of flux recovered. However, a device other than the inverter 31, such as a PLC 32 or PC 33, may also be used as a control device that detects the amount of flux recovered.

[0059] In one embodiment, an example was described in which, if it is determined that the number of detections of the flux recovery amount n is 0, the processes from steps S12 to S21 are performed, and if it is determined that the number of detections of the flux recovery amount n is greater than 0, the processes from steps S22 to S28 are performed (see Figure 6). However, the operation of the reflow apparatus 101 is not limited to this example, and for example, if the number of detections of the flux recovery amount n is a predetermined number of n a The following (however, n a If it is determined that ≥ 1), the process from steps S12 to S21 is performed, and the number of detections of the flux recovery amount n is set to a predetermined number of n a If it is determined to be greater than the specified value, the process from steps S22 to S28 may be performed. Alternatively, the inverter 31 may detect the point in time when the time change of the torque value changes from decreasing to increasing, and the process from steps S12 to S21 may be performed during the period up to that point, and the process from steps S22 to S28 may be performed during the period after that point.

[0060] In one embodiment, an example was described in which the inverter 31 calculates the torque value of the motor 232 from motor information received from the motor 232. However, the method of obtaining the torque value is not limited to this example, and for example, the control system 30 may further include a torque meter for detecting the torque value of the motor 232. In this case, the inverter 31 may use the torque value detected by the torque meter to detect that the amount of flux recovered has reached a predetermined amount.

[0061] Although embodiments and modifications thereof of the present invention have been specifically described above, the invention is not limited to the embodiments and modifications thereof, and various modifications based on the technical idea of ​​the present invention are possible. For example, the configurations, methods, processes, shapes, materials, and numerical values ​​given in the embodiments and modifications thereof are merely examples, and different configurations, methods, processes, shapes, materials, and numerical values ​​may be used as needed. Furthermore, the configurations, methods, processes, shapes, materials, and numerical values ​​of the embodiments and modifications thereof can be combined with each other as long as they do not depart from the spirit of the present invention. [Explanation of Symbols]

[0062] 10... Furnace body, 101... Reflow unit, 11, 12... Piping, 20... Flux recovery unit, 21... Case, 22... Cooling unit, 23... Blower, 30... Control system, 31... Inverter, 32... PLC, 33... PC, 34... Equipment, 102a... Heating chamber, 102b... Cooling chamber, 103... Conveyor chain, 104a, 1 04b, 104c, 104d... Rotating body, 105... Outer plate, 106... Inlet, 107... Outlet, 211... Flux recovery chamber, 212... Fan chamber, 231... Fan, 232... Motor, R1... Heating section, R2... Preheating section, R3... Reflow (main heating) section, R4... Cooling section, W... Workpiece, Z1~Z9... Zone

Claims

1. The furnace body and The conveying section transports the object to be heated within the furnace body, A flux recovery device that uses a blower to draw in the atmospheric gas inside the furnace and recovers the flux contained in the atmospheric gas, A control device that detects whether the amount of flux recovered has reached a predetermined amount based on the torque change of the blower motor. A reflow apparatus equipped with the following features.

2. The reflow apparatus according to claim 1, wherein the control device calculates the amount of torque change of the blower motor using the torque value that decreases with the elapsed operating time of the blower immediately after the blower is driven.

3. The reflow apparatus according to claim 1 or 2, wherein the control device calculates the amount of torque change of the blower motor using the torque value that increases with the elapsed operating time of the blower.

4. The reflow apparatus according to claim 1 or 2, wherein the control device detects the maximum torque value immediately after the blower is driven, and based on the maximum torque value, detects that the amount of flux recovered has reached a predetermined amount.

5. The reflow apparatus according to claim 3, wherein the control device detects the maximum torque value immediately after the blower is driven, and based on the maximum torque value, detects that the amount of flux recovered has reached a predetermined amount.

6. The reflow apparatus according to claim 1, wherein the flux recovered by the flux recovery device is a liquid.

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