Conveying and heating device

Abstract

This improves work efficiency during heating condition measurement and reduces the risk of the substrate falling. [Solution] A transport heating device comprising a heating device configured to blow hot air onto a substrate using multiple heating furnaces arranged in a row, and a transport conveyor for transporting substrates to the heating device, wherein the transport heating device comprises an outlet sensor provided on the outlet side of the heating device for detecting substrates, and a control unit to which the detection signal from the outlet sensor is supplied, and when the heating condition measurement mode of the heating device is set, the control unit stops the transport operation of the transport conveyor when a substrate for temperature profile measurement is detected by the outlet sensor.

Description

Technical Field

[0005] , ,

[0006]

[0001] The present invention relates to a conveyance heating device applied to, for example, a reflow device.

Background Art

[0002] A reflow device includes a reflow furnace to which a printed circuit board on which surface mount components are mounted on both sides of a work, such as a printed board, as a heated object, is supplied by a conveyance conveyor. The reflow furnace has, for example, a configuration in which a plurality of heating zones having heating furnaces and one or a plurality of cooling zones are sequentially arranged along a conveyance path from an inlet to an outlet.

[0003] Each of the heating zones has an upper furnace body and a lower furnace body. For example, hot air is blown onto the substrate from the upper furnace body of the zone, and hot air is blown onto the substrate from the lower furnace body, thereby melting the solder in the solder composition and soldering the electrodes of the substrate and the electronic components.

[0004] In a reflow device, it is necessary to manage the heating conditions during soldering. The heating conditions include temperature, oxygen concentration, the speed of the conveyance conveyor, and the like. In the following description, the case of managing the soldering temperature will be described. The temperature management is performed based on a temperature profile. The temperature profile is a graph of the soldering temperature of the printed circuit board and the passage of time.

[0005] In a reflow device, even after a new temperature profile is set, the temperature profile is measured daily, for example, at the start of a day's operation, and the reflow device is controlled based on the measured temperature. For example, the error between the reference temperature profile and the measured temperature profile is corrected. The soldering condition measurement operation state for measuring the temperature profile is appropriately referred to as the profile mode. The profile mode is an example of the heating condition measurement mode.

[0006] There are two types of methods (devices) for measuring temperature profiles. A circuit board (appropriately referred to as a temperature profile measurement circuit board) has thermocouples at a predetermined number of locations for temperature measurement. A processing device (appropriately referred to as a data logger) is provided to process the outputs of the multiple thermocouples and store them as digital data. One type of temperature profile measurement device has a configuration in which one end of a thermocouple is connected to the measurement location on the temperature profile measurement circuit board, and the other end of the thermocouple, which has passed through the furnace, is connected to a data logger outside the furnace (hereinafter appropriately referred to as a wired measuring device).

[0007] Other types include a transmitter built into a heat-resistant case immediately after the temperature profile measurement board, which is transported together with the temperature profile measurement board. A thermocouple is connected to a connector on the transmitter, which converts the signal into a digital signal and transmits it to a receiver outside the reflow machine. A personal computer is connected to the receiver (hereinafter referred to as a wireless measuring instrument).

[0008] In the case of wired measuring instruments, several meters of thermocouples were attached to a temperature profile measuring board during temperature profile measurement, and the temperature profile measuring board was transported. After measurement, the transport conveyor was stopped and the thermocouples and temperature profile measuring board were collected from the entrance side. In the case of wireless measuring instruments, the temperature profile measuring board and the transmitting device were transported together, and after measurement, the transport conveyor was not stopped, and the temperature profile measuring board and transmitting device were collected as they flowed out from the exit side. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent No. 5310634 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] Patent Document 1 describes a system in temperature profile mode that includes a sensor at the inlet to detect the arrival of a substrate, and determines the time elapsed since the substrate was detected before an alarm is triggered. The alarm is intended to signal that the time for the substrate to be discharged from the furnace is approaching.

[0011] However, this method has the problem that the operator of the reflow machine must be near the machine when the substrate is ejected, resulting in inefficient temperature profile measurement. If the operator is not nearby when the profile measurement is completed, in the case of wireless measuring instruments, the transmitter may be transported outside the furnace and fall off the conveyor belt. In the case of wired measuring instruments, there was a problem of excessive tension being applied to the connection point between the thermocouple and the temperature profile measurement substrate. The invention described in Patent Document 1 is for wireless measuring instruments and does not take into consideration wired measuring instruments.

[0012] Therefore, the object of this invention is to provide a transport heating device that can improve work efficiency in profile mode, prevent the transmitter of a wireless measuring instrument from falling outside the furnace, and is applicable to both wireless and wired measuring instruments. [Means for solving the problem]

[0013] The present invention relates to a heating device comprising a heating device in which a plurality of heating furnaces are arranged and hot air is blown onto a substrate by the heating furnaces, and a conveying conveyor for transporting substrates to the heating device, An outlet sensor is provided on the outlet side of the heating device to detect the substrate, It comprises a control unit to which a detection signal from an exit sensor is supplied, This is a transport heating device in which, when the heating condition measurement mode of the heating device is set, the control unit stops the transport operation of the transport conveyor when a substrate is detected by the outlet sensor. [Effects of the Invention]

[0014] According to at least one embodiment, in the profile mode, it is not necessary for an operator to wait beside the reflow device, and it is possible to prevent the substrate for temperature profile measurement and the transmission device from dropping outside the furnace. Furthermore, it can be applied to both wired and wireless measuring instruments. Note that the effects described here are not necessarily limited, and any of the effects described in the present invention may be applicable. Also, the content of the present invention is not limited to the effects exemplified in the following description.

Brief Description of the Drawings

[0015] [Figure 1] FIG. 1 is a schematic diagram showing an overview of a conventional reflow device to which the present invention can be applied. [Figure 2] FIG. 2 is a graph showing an example of a temperature profile during reflow. [Figure 3] FIG. 3 is a block diagram showing the configuration of a control device according to an embodiment of the present invention. [Figure 4] FIG. 4 is a flowchart for explaining a part of the processing of an example of control in an embodiment of the present invention. [Figure 5] FIG. 5 is a flowchart for explaining the remaining part of the processing of an example of control in an embodiment of the present invention. [Figure 6] FIG. 6 is a flowchart for explaining a part of the processing of another example of control in an embodiment of the present invention. [Figure 7] FIG. 7 is a flowchart for explaining the remaining part of the processing of another example of control in an embodiment of the present invention.

Modes for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described. The description will be made in the following order. <1. An Example of a Reflow Device> <2. An Embodiment> <3. Variations> Note that one embodiment described below is a preferred specific example of the present invention and is technically subject to various preferable limitations. However, the scope of the present invention is not limited to these embodiments in the following description, unless there is a description to specifically limit the present invention.

[0017] <1. Example of a reflow apparatus> FIG. 1 shows a schematic configuration of a conventional reflow apparatus to which the present invention can be applied. A printed circuit board (hereinafter appropriately referred to as a substrate) on which surface-mount electronic components are mounted on both sides of a printed wiring board is placed on a conveyor and carried into a heating device of the reflow apparatus through an inlet side throat portion 104 from a carry-in port 101. The conveyor conveys the substrate in the direction of the arrow (from left to right in FIG. 1) at a predetermined speed, and the substrate is taken out from a carry-out port 102 through an outlet side throat portion 105. The conveyance direction of the conveyor is in the horizontal direction.

[0018] The heating device is configured such that a plurality of heating furnaces are arranged along a conveyance path from the carry-in port 101 to the carry-out port 102, and hot air (heated ambient gas) is blown against the substrate by the heating furnaces. A plurality of heating furnaces (referred to as zones) are arranged in an in-line manner. Eight zones Z1 to Z8 from the inlet side are heating zones, and a zone Z9 on the outlet side is a cooling zone. A forced cooling unit 103 is provided in relation to the cooling zone Z9. Each of the heating zones Z1 to Z8 has an upper furnace body and a lower furnace body including a blower, a heater, a blowing panel, and the like. Note that the number of these zones is an example, and a configuration having a different number of zones may also be used.

[0019] Furthermore, an inlet sensor for counting the number of substrates carried into the furnace (appropriately referred to as inside the apparatus) is provided near the carry-in port 101, for example, in the inlet side throat portion 104. Also, an outlet sensor for counting the number of substrates carried out of the furnace, for example, in the outlet side throat portion 105 near the carry-out port 102 is provided. As the inlet sensor and the outlet sensor, for example, transmissive optical sensors can be used.

[0020] The aforementioned zones Z1 to Z9 control the substrate temperature according to the reflow temperature profile. 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 substrate, for example, a substrate on which electronic components are mounted. 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 main heating section R3, and the last section is the cooling section R4. The heating section R1 and the preheating section R2 are preheating sections.

[0021] The heating section R1 is the period during which the substrate 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 substrate. The main heating 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. In the main heating section R3, it is necessary to raise the temperature to a level above the solder melting point. Even after passing through the preheating section R2, uneven temperature rise may exist, so heating to a level above the solder melting point is necessary in the main heating section R3. The final cooling section R4 is the period during which the printed circuit board is rapidly cooled and the solder composition is formed. In the case of lead-free solder, the temperature in the main heating section R3 will be higher (e.g., 240°C to 260°C).

[0022] In Figure 2, curve 201 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 202. Since the melting point of lead-free solder is higher than that of eutectic solder, the set temperatures in the preheating section R2 and the main heating section R3 are set higher compared to those for eutectic solder.

[0023] In the reflow apparatus shown in Figure 1, the temperature control of the heating section R1 in Figure 2 is mainly handled by zones Z1, Z2, and Z3. The temperature control of the preheating section R2 is mainly handled by zones Z4 and Z5. The temperature control of the main heating section R3 is handled by zones Z6, Z7, and Z8. The temperature control of the cooling section R4 is handled by zone Z9. Gaps exist between the multiple furnace bodies (zones) described above. The entire heating furnace that handles the heating section R1 and the preheating section R2 is called the preheat zone, the entire heating furnace that handles the main heating section R3 is called the reflow zone, and the preheat zone and reflow zone together are called the heating zone.

[0024] <2. One Embodiment> A control device 10 in one embodiment of the present invention will be described with reference to Figure 3. A user interface 11 is provided. The user interface 11 includes a display unit 12 and an operation unit 13. For example, a personal computer can be used as the user interface 11.

[0025] The display unit 12 displays the operating status of the reflow machine, message boxes, and other information. The operation unit 13 includes user-operated switches such as a keyboard and touch switches, and also contains a profile mode setting button and a reset switch.

[0026] The user interface 11 is provided in conjunction with a controller 14, which is configured, for example, as a PLC (Programmable Logic Controller). The controller 14 controls the reflow machine according to a pre-created program. Detection outputs from the inlet sensor 15 and the outlet sensor 16 are supplied to the controller 14.

[0027] Furthermore, the controller 14 generates control signals to the notification unit 17. The notification unit 17 is, for example, a buzzer that generates an alarm. The alarm may be generated by light in addition to sound. Furthermore, sound and light may be used in combination. In addition, the notification unit 17 includes an indicator light (referred to as a signal tower) which is installed near the reflow machine and is cylindrical in shape and lights up, turns off, or flashes multiple colors. Furthermore, the controller 14 is connected to the conveyor drive unit 18, and the controller 14 controls the start / stop of the conveying operation of the conveyor and the conveying speed.

[0028] An example of the control operation performed by the control device 10 described above will be explained with reference to the flowcharts in Figures 4 and 5.

[0029] Step S1: The reflow machine is in "automatic operation" mode. Step S2: Based on the count values ​​of the inlet sensor 15 and the outlet sensor 16, it is determined whether the number of circuit boards inside the device is 0. If it is determined that the number of circuit boards inside the device is 0, mode switching becomes possible, and the process moves to step S3.

[0030] Step S3: The profile mode button is operated. Step S4: Profile mode starts. In profile mode, the request signal is stopped, the counting of the number of boards is stopped, the device status is set to "profile mode", and the conveyor starts transporting at the set speed.

[0031] Stopping the request signal means the reflow machine stops requesting boards. This is a necessary process to prevent other boards from passing through the furnace during profile mode. Stopping the board count is the process of stopping the counting of boards within the machine. This is a process to prevent counting the number of boards produced. Since automatic operation is already underway before starting profile mode, conveyor transport is already occurring. Therefore, no special control is required to start conveyor transport.

[0032] Step S5: The temperature profile measurement substrate is loaded into the apparatus. Step S6: The signal tower flashes green.

[0033] Step S7: The temperature profile measurement board is detected as the outlet board. That is, the temperature profile measurement board is detected by the outlet sensor 16 located at the outlet. Step S8: The buzzer turns ON (sounds) and the conveyor stops. Step S9: The reset button is pressed down. Step S10: The buzzer turns OFF (stops sounding).

[0034] Step S11: The operator determines whether the measuring instrument (transmitter) was transmitted together with the circuit board.

[0035] Step S21: If the result of Step S11 is positive, it means that a wireless measuring instrument was used, in which case the reset button is pressed and held. Step S22: The profile mode termination process is performed. That is, the conveyor speed is set to a speed that is above the minimum speed limit and below half of the set value, and the circuit board display shown on the display unit 12 is turned off.

[0036] Step S23: The substrate and measuring instrument are retrieved from the exit side of the reflow machine. As the substrate and measuring instrument are sent to the exit side at a low speed, they can be easily removed from the exit side. In addition, since the conveyor speed is low, the risk of the substrate and measuring instrument for temperature profile measurement falling is reduced. Step S24: The reset button is pressed down. Step S25: The conveyor speed returns to the set speed. Step S26: The device status returns to "Automatic Operation". Production operation can then begin.

[0037] Step S31: If the result of the determination in Step S11 is negative, it means that a wired measuring instrument was used, the measuring instrument (data logger) is located near the outside of the device, and the thermocouple is long. Therefore, after the profile mode is completed, the thermocouple and temperature profile measurement board are recovered from the inlet side of the reflow machine. Since the conveyor is stopped, the recovery of the thermocouple and temperature profile measurement board can be carried out without any problems. Step S32: The reset button is pressed down. Step S33: The profile mode termination process is performed. That is, the conveyor operation is turned ON, and the circuit board display shown on the device monitor is reset. Then, the process moves to step S26 (device status returns to "automatic operation").

[0038] Other examples of control operations performed by the control device 10 described above will be explained with reference to the flowcharts in Figures 6 and 7.

[0039] Step S41: The reflow machine is in "automatic operation" mode. Step S42: Based on the count values ​​of the inlet sensor 15 and the outlet sensor 16, it is determined whether the number of circuit boards inside the device is 0. If it is determined that the number of circuit boards inside the device is 0, mode switching becomes possible, and the process moves to step S43.

[0040] Step S43: The profile mode button is operated. Step S44: Profile mode is started. In profile mode, the request signal is stopped, the counting of the number of boards is stopped, the device status is set to "profile mode", and the conveyor starts transporting at the set speed.

[0041] Request signal stop means the reflow machine stops requesting boards. This is a necessary process to prevent other boards from passing through during profile mode. Board count stop is the process of stopping the counting of boards within the machine. This is a process to prevent counting the number of boards produced. Since automatic operation is already underway before starting profile mode, conveyor transport is already occurring. Therefore, no special control is required to start conveyor transport.

[0042] Step S45: Either a wired or wireless measuring instrument is selected. If a wireless measuring instrument is selected, the temperature profile measurement board and the measuring instrument (transmitter) are brought into the device. If a wired measuring instrument is selected, the temperature profile measurement board is brought into the device, but the measuring instrument is not brought into the device. The subsequent processes are shown in the flowchart in Figure 7.

[0043] Step S51: Since a wireless measuring instrument has been selected, the temperature profile measurement board and the measuring instrument are loaded into the device. Step S52: The signal tower flashes green.

[0044] Step S53: The temperature profile measurement board is detected as the outlet board. That is, the temperature profile measurement board is detected by the outlet sensor 16 provided at the outlet. Step S54: The buzzer turns ON (sounds) and the conveyor stops. Step S55: The reset button is pressed down. Step S56: The buzzer turns OFF (stops sounding).

[0045] Step S57: If a wireless measuring instrument is used, the reset button is pressed and held. Step S58: The profile mode termination process is performed. That is, the conveyor speed is set to half or less of the set value, and the circuit board display on the display unit 12 is turned off.

[0046] Step S59: The temperature profile measurement board and measuring instrument are retrieved from the outlet side of the reflow machine. As the temperature profile measurement board and measuring instrument are sent to the outlet side at a low speed, they can be easily retrieved from the outlet side. In addition, because the conveyor speed is low and an operator is nearby, the risk of the temperature profile measurement board and measuring instrument falling is reduced. Step S60: The reset button is pressed down. Step S61: The conveyor speed returns to the set speed. Step S62: The device status returns to "Automatic Operation". Production operation can then begin.

[0047] Step S71: Since a wired measuring instrument has been selected, the temperature profile measurement board is loaded into the device. Step S72: The signal tower flashes green.

[0048] Step S73: The temperature profile measurement board is detected as the outlet board. That is, the temperature profile measurement board is detected by the outlet sensor 16 provided at the outlet. Step S74: The buzzer turns ON (sounds) and the conveyor stops. Step S75: The reset button is pressed down. Step S76: The buzzer turns OFF (stops sounding).

[0049] Step S77: After the profile mode is completed, the thermocouple and temperature profile measurement board are retrieved from the inlet side of the reflow machine. Since the conveyor is stopped, the retrieval of the thermocouple and temperature profile measurement board can be carried out without any problems. Step S78: The reset button is pressed down. Step S79: The profile mode termination process is performed. That is, the conveyor operation is turned ON, and the circuit board display shown on the device monitor is reset. Then, the process moves to step S62 (device status returns to "automatic operation").

[0050] According to the embodiment described above, work efficiency can be improved in thermoprofile mode for both wired and wireless measuring instruments, and the substrate can be prevented from falling. In the case of a wired measuring instrument, a buzzer sounds and the conveyor belt stops when the measurement is completed. After the operator hears the buzzer and presses the reset button to stop the buzzer, the thermocouple and temperature profile measuring substrate are retrieved from the entrance side of the device.

[0051] In the case of wireless measuring instruments, a buzzer sounds and the conveyor belt stops when the measurement is complete. Upon hearing the buzzer, the operator stops the buzzer by pressing the reset button in a different manner, for example, by holding it down. After moving the conveyor belt at a speed lower than the set speed, for example, half or less, the operator retrieves the transmitter and temperature profile measurement board from the exit side of the device. Therefore, the transmitter and temperature profile measurement board, which are stopped at the back from the entrance side, are carried out and can be easily retrieved. Whether using wired or wireless measuring instruments, it is not necessary for the operator to be near the reflow machine, nor is it necessary for them to rush over upon hearing the buzzer.

[0052] <3. Variant> Although embodiments of the present invention have been specifically described above, the invention is not limited to the embodiments described above, and various modifications are possible based on the technical concept of the present invention. For example, the present invention can be applied to cases where other conditions besides temperature, such as oxygen concentration and substrate inclination, are measured as heating conditions for the object to be measured. Furthermore, the present invention can be applied to flow soldering equipment, and is not limited to soldering equipment, but can also be applied to thermosetting equipment and the like. Note that the configurations, methods, processes, shapes, materials, and numerical values ​​listed in the embodiments described above are merely examples, and different configurations, methods, processes, shapes, materials, and numerical values ​​may be used as needed. In addition, the configurations, methods, processes, shapes, materials, and numerical values ​​of the embodiments described above can be combined with each other as long as they do not deviate from the spirit of the present invention. [Explanation of Symbols]

[0053] 101...Inlet, 102...Outlet, 10...Control device, 11...User interface, 14...Controller, 15...Inlet sensor, 16...Outlet sensor, 17...Notification unit, 18...Conveyor drive unit

Claims

1. A heating device comprising a heating device having multiple heating furnaces arranged in a row and configured to blow hot air onto a substrate using the heating furnaces, and a conveying conveyor for transporting the substrate to the heating device, An outlet sensor is provided on the outlet side of the heating device to detect the substrate, The system comprises a control unit to which the detection signal from the outlet sensor is supplied, A transport heating device wherein, when the heating condition measurement mode of the heating device is set, the control unit stops the transport operation of the transport conveyor when the outlet sensor detects the temperature profile measurement substrate.

2. The conveying heating device according to claim 1, wherein the conveying conveyor performs a conveying operation at a predetermined speed after the conveying operation of the conveying conveyor has stopped.

3. The conveying and heating apparatus according to claim 2, wherein the predetermined speed is less than or equal to the set speed.

4. The conveying and heating apparatus according to claim 2, wherein the predetermined speed is 1 / 2 or less of the set speed.

5. The conveying heating device according to any one of claims 1 to 4, wherein the control unit stops the conveying operation of the conveying conveyor and generates an alarm sound.

6. The transport heating apparatus according to any one of claims 1 to 4, wherein the exit sensor also serves as a substrate count counter.

7. The transport heating apparatus according to any one of claims 1 to 4, wherein the temperature of the heating apparatus is measured by a wired measuring instrument in which a data logger for processing thermocouple measurements on a temperature profile measuring substrate is located externally.

8. A transport heating device according to any one of claims 1 to 4, wherein a transmitting device to which a thermocouple measurement value of a temperature profile measuring substrate is supplied is transported together with the temperature profile measuring substrate, and a receiving device that receives a signal from the transmitting device measures the temperature of the heating device using a wireless measuring instrument located externally.

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