JP2010004013A - Reflow apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ductless reflow apparatus capable of preventing a flux from accumulating in a furnace or depositing to a substrate, and at the same time capable of improving temperature independence of each heating zone. <P>SOLUTION: The output of each heater 21 is controlled so as to allow an actually measured temperature of each heating zone Z to approach a predetermined temperature range which has been set for each heating zone Z. Also, in the heating zone where the actually measured temperature is higher than the predetermined temperature range when the actually measured temperature in the heating zone Z is increasing with time, a control valve 44 in the heating zone Z is opened, and at the same time, when the actually measured temperature is decreasing with time, the control valve 44 in the heating zone Z is closed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reflow apparatus used when soldering a component to a printed circuit board or the like, and more particularly to a ductless reflow apparatus that hardly discharges internal gas to the outside.

  The ductless reflow device is a reflow device having a structure that does not particularly have an exhaust pipe to the outside and hardly leaks an internal heating gas to the outside, and can be used as it is installed in a factory. However, even though the gas is not leaked to the outside, the substrate inlet / outlet is actually opened, and the heating gas flows out little by little from here.

  And since this heating gas is mixed with an impurity called flux that is vaporized when the circuit board is soldered, in a ductless reflow device having no exhaust pipe, a normal reflow device and On the other hand, it is particularly important from the viewpoint of the working environment to prevent impurities from entering the heating gas flowing out.

  Therefore, conventionally, as shown in Patent Document 1 and Patent Document 2, after the internal heating gas is sucked and passed through a flux remover such as a cooler, a throttle, and a filter, the flux contained in the gas is removed. It has been considered to provide a circulation type flux removing mechanism for returning to the furnace again. According to such a configuration, it is possible to prevent accumulation of impurities in the furnace and adhesion of the substrate.

JP 2007-67061 A JP 2003-324272 A JP-A-1992-94867 JP 2006-196858 A JP 2007-67061 A JP 2007-178064 A

However, cooling the internal heating gas and returning it again naturally requires that the heater output be increased by the amount of cooling to maintain the furnace temperature, resulting in energy loss. End up. In particular, in a state where the temperature is controlled by balancing excessive cooling and excessive heating, useless energy loss increases. In view of the remarkably high energy consumption of the reflow equipment among various devices related to the substrate manufacturing process, this energy loss has a great influence on the manufacturing cost, and the point of global environmental problems such as CO ₂ consumption. This is also not preferable.

  Therefore, it is important to minimize the cooling function, that is, to minimize the amount of gas to be cooled in order to remove impurities. However, simply minimizing the gas to be cooled can quickly lower the temperature when the temperature in the heating zone rises too much due to the effects of the adjacent zone temperature, heat storage on the furnace outer wall, etc. It becomes difficult, and the malfunction that the temperature controllability of each heating zone becomes bad may arise. For example, even if the heating zone is subdivided and temperature control with a sharp edge is performed, an accurate profile cannot be created, and it becomes difficult to improve ΔT and the like beyond a certain level.

  On the other hand, Patent Documents 1 and 2 mentioned above describe how to balance such a problem, that is, how to balance the flow rate of the cooling gas and the output of the heater from the viewpoint of energy consumption and temperature control. In addition, even if patent documents (for example, Patent Documents 3 to 6) relating to temperature control of the reflow apparatus are looked over, there is no particular mention. The fact is that even issues are not recognized.

  Therefore, the present invention has been made in view of this problem, and its main purpose is to solve the conflicting problems of reducing the energy consumption as much as possible and improving the temperature controllability of each heating zone at once. It is an object of the present invention to provide a ductless type reflow apparatus capable of performing the above.

That is, the reflow apparatus according to the first aspect of the present invention includes a furnace in which a plurality of heating zones that can be adjusted to different temperatures are arranged in series, and is soldered by passing a substrate through each heating zone. Which is configured as follows:
A gas circulation chamber attached to each heating zone, one cooling circuit common to each heating zone, and a control unit,
The gas circulation chamber has a heater and a first blower for gas circulation inside, and blows out gas from a gas outlet opened in each heating zone, and from a gas inlet opened in each heating zone. Gas inhalation,
The cooling circuit has a gas inlet end opened to a predetermined gas circulation chamber or heating zone and a gas discharge end opened to each gas circulation chamber or heating zone, and a cooling gas passage on the cooling gas passage. A cooler provided, a second blower provided on a cooling gas flow path downstream of the cooler and pumping gas, and a gas flow rate adjusted from each gas discharge end And a control valve,
The controller controls the output of each heater to bring the measured temperature of each heating zone closer to the set temperature range set for each heating zone, and the measured temperature is set. For a heating zone higher than the temperature range, if the measured temperature in the heating zone increases with time, the control valve in the heating zone is driven in the opening direction, while the measured temperature decreases with time. In this case, the control valve control means for driving the control valve in the heating zone in the closing direction is provided.

  According to the present invention having such a configuration, the opening degree of the adjustment valve for cooling is not simply determined from the deviation between the set temperature and the actually measured temperature, but the adjustment valve is driven early by monitoring the time change of the actually measured temperature. Therefore, quick and stable temperature control of each heating zone becomes possible. Since the temperature can be quickly and stably controlled, the temperature is not excessively lowered, and an unnecessary increase in the output of the heater can be avoided. That is, it is possible to simultaneously reduce the energy consumption as much as possible and improve the temperature controllability of each heating zone.

  By the way, when all the control valves are closed, the outlet of the cooling circuit is blocked and the internal pressure is increased. If the control valve is opened from this state, a large flow rate may flow in despite the slight opening, and the temperature of the heating zone may drop too rapidly. In order to avoid this, a cooling zone disposed downstream of the heating zone and a gas circulation chamber attached to the cooling zone are provided, and the gas discharge end and the gas suction end of the cooling gas flow path are connected to the cooling zone or When opening the gas circulation chamber and providing an adjustment valve for adjusting the flow rate of gas discharged from the gas discharge end, and all the adjustment valves at least in the heating zone are closed by the control unit In this case, the control valve in the cooling zone may be controlled to open.

  Conversely, if the adjustment valve for the heating zone is open and the adjustment valve for the cooling zone is open, the cooling function for the heating zone will drop, so the adjustment valve for the heating zone is opened to lower the measured temperature. In the state, it is desirable to keep the opening degree of the adjustment valve in the cooling zone below a predetermined value or closed.

  In order to further improve the temperature controllability, the control unit increases the measured temperature in the heating zone over time for a heating zone in which the measured temperature is higher than the set temperature range by a predetermined temperature or more. When the opening of the control valve is maximum, it is preferable that the apparatus further includes blower control means for controlling the output of the second blower in the increasing direction.

  In order to minimize damage to the substrate in an unforeseen situation, when the measured temperature exceeds a limit temperature that is a predetermined temperature higher than the set temperature range during the soldering operation, at least It is desirable to further include a notifying unit for notifying that the board loading is prohibited.

  In order to suppress the gas flow between the heating zones as much as possible and facilitate the independent temperature control in each heating zone, the gas circulation chambers are respectively arranged above and below the substrate passage area in each heating zone. The gas outlets in the upper and lower gas circulation chambers are arranged so as to face each other, and the gas suction ports are formed on both sides of the gas outlets, while the gas circulation chambers adjacent to each other in the substrate passing direction are A gas separation plate extending a predetermined distance is provided, and the gas blown out from the opposing gas outlets in one heating zone hits the substrate when there is a substrate, and collides with each other when there is no substrate and horizontally The flow is changed in the direction, sucked from the gas suction port of the heating zone, passed through the heater and blower arranged in the gas circulation chamber, and again blown out from the gas outlet It shall is preferred.

  With such a configuration, although each heating zone is in physical communication and does not hinder the passage of the substrate, gas flow between the heating zones is prevented, so the gaseous state contained in the gas Impurities can be very effectively prevented from flowing into the heating zones of different temperatures, liquefying or solidifying, and accumulating in the furnace. In addition, since the gas flow between the heating zones can be suppressed in this way, the temperature effect of the adjacent heating zones becomes as small as possible, and the temperature of each heating zone can be controlled independently and stably. It becomes like this. As a result, a profile that gives a temperature difference between the heating zones can be accurately created, and ΔT can be effectively reduced.

  If the cooling circuit has an impurity removal function of liquefying and removing impurities contained in the gas, not only the accumulation of impurities in the furnace but also the removal of impurities can be performed.

  In order to efficiently remove impurities by connecting a cooling circuit to a heating zone in which a lot of impurities are generated, the cooling can be performed in a heating zone having a set temperature different from that in the preceding heating zone or in the first heating zone. It is preferable to open the gas suction end of the circuit.

  If the cooler is provided at substantially the same height as or below the lower gas circulation chamber, the gas circulation chamber can be used in the event of unforeseen events such as a power failure due to liquefaction and accumulation in the cooler. And return to the substrate passage region can be prevented with a simple configuration.

  A partition wall is provided inside the gas circulation chamber to form a heater accommodating chamber for accommodating a heater and a blower accommodating chamber for accommodating a blower, and a gas inlet provided in the heater accommodating chamber is a heater. A communication hole of a predetermined size is provided in a part of the partition wall located on the substantially opposite side across the gas, and the gas is blown out from the gas outlet through the heater housing chamber, the communication hole, and the blower housing chamber in this order. By doing so, the gas sufficiently heated by the heater can be blown out from the gas outlet by the blower, and the gas can be heated efficiently.

  If the furnace is formed by connecting a plurality of furnace units that form one or a plurality of heating zones, and each furnace unit is configured to be able to contact and separate, standardization of parts by unitization is possible. It is possible to easily produce furnaces with various numbers of heating zones. Moreover, partial maintenance can be facilitated by separating the furnace unit.

  If there are two types of furnace units, a first furnace unit that forms two heating zones and a second furnace unit that forms three heating zones, only two standard products can be used. It can correspond to the reflow device. In addition, manufacturing is easier than making a furnace unit in a single heating zone.

  Note that the temperature of the zone to be measured is most preferable because the temperature of the gas sprayed onto the substrate indicates a substantial reflow temperature. A temperature in the vicinity of the gas outlet is desirable as a site that is similar to that and that is easy to measure and suitable for temperature control. Any other temperature in the zone may be used.

  According to the present invention configured as described above, the opening of the control valve for cooling is not simply determined from the deviation between the set temperature and the measured temperature, but the control valve is driven early by monitoring the time change of the measured temperature. Therefore, quick and stable temperature control of each heating zone becomes possible. Since the temperature can be quickly and stably controlled, the temperature is not excessively lowered, and an unnecessary increase in the output of the heater can be avoided. That is, it is possible to simultaneously reduce the energy consumption as much as possible and improve the temperature controllability of each heating zone. Further, since the gas only circulates in the furnace, so-called ductless operation is possible, and the discharge of impurities to the outside can be reduced as much as possible.

The typical whole block diagram of the reflow apparatus which concerns on one Embodiment of this invention. The typical internal structure figure which shows an internal structure when the gas circulation chamber in the embodiment is seen from a substrate passage direction. The typical internal structure figure which shows an internal structure when the gas circulation chamber in the embodiment is seen from the horizontal direction orthogonal to the substrate passage direction. FIG. 3 is a schematic plan view showing a gas outlet in the same embodiment. FIG. 2 is a schematic structural diagram showing an impurity removal circuit in the same embodiment. In the same embodiment, the flowchart which shows the control procedure with respect to the adjustment valve and cooling gas circulation blower from start to production. The flowchart which shows the control procedure with respect to the heater in the embodiment. The flowchart which shows the production start process routine in the embodiment. The flowchart which shows the control procedure with respect to the adjustment valve and cooling gas circulation blower at the time of changing preset temperature in the same embodiment. The schematic diagram which shows the furnace unit in other embodiment of this invention. The schematic diagram which shows an example which connected the furnace unit in the same embodiment, and formed the furnace.

  An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic overall configuration of a reflow apparatus 100 according to the present embodiment.
As shown in FIG. 1, the reflow apparatus 100 has a plurality of heating zones Z that can be adjusted to different temperatures (hereinafter, when distinguishing heating zones, the number of steps is added in parentheses after Z). The furnace 1 is connected in series, and is configured to be soldered when the substrate P passes through each heating zone Z at a constant speed. Incidentally, in FIG. 1, six heating zones Z (1) to Z (6) are described, and the first to fourth heating zones Z (1) are viewed from the side where the substrate P is carried. ) To Z (4) are preheating zones, and the fifth and sixth heating zones Z (5) and Z (6) are main heating zones in which solder melting is performed. In FIG. 1, the symbol AR described at the center of the upper and lower sides of the heating zone Z indicates a substrate passing area which is a trajectory through which the substrate passes. The zone ZZ provided at a further stage of the main heating zone Z (6) is The cooling zone. When mentioning an example of the set temperature of each heating zone Z (1) to Z (6), for example, the first stage heating zone Z (1) is 200 ° C., the second stage and the third stage heating zone Z (2) and Z (3) are each 150 ° C., the fourth heating zone Z (4) is 190 ° C., the fifth and sixth heating zones Z (5) and (6) are each 250 ° C. is there.

  Gas circulation chambers 2 are provided above and below each heating zone Z. As shown in FIGS. 2, 3, and 4, the gas circulation chamber 2 includes a gas outlet 2 a that opens to the upper and lower surfaces of the heating zone Z and blows gas up and down the substrate, and the gas outlet 2 a. Gas inlets 2b formed on both sides along the substrate passage direction. The gas outlet 2a has a rectangular shape (substantially square shape), and a book board material having a large number of through holes is fitted therein. The upper and lower gas outlets 2a face each other. More specifically, the through holes face each other vertically. The gas suction port 2b has a belt-like shape formed adjacent to the gas outlet 2a, and the length in the width direction (direction perpendicular to the paper surface in FIG. 1) is substantially the same as that of the gas outlet 2a. .

  A gas separation plate 3 is provided between the gas circulation chambers 2 adjacent in the substrate passage direction. The gas separation plate 3 is provided across the width direction between the gas inlet 2b in one heating zone Z and the gas outlet 2a in the adjacent heating zone Z, and toward the substrate passage area AR. It is a thin plate that extends a predetermined distance to the extent that the passage of the substrate P is not hindered.

  With this configuration, the gas blown out from the gas outlets 2a facing each other in a certain heating zone Z hits the substrate P when the substrate P is in the substrate passage area AR, and collides with each other when there is no substrate P and horizontally The flow is changed to almost all of the air and is sucked from the gas suction port 2b of the heating zone Z.

  Further, the gas circulation chamber 2 is provided with a partition wall 23 inside, a heater housing chamber 24 for housing an electric heater 21 as a heater, and a first blower 22 (hereinafter also referred to as a heating gas circulation blower 22). And a blower housing chamber 25 for housing the housing.

  The partition wall 23 is provided with a communication hole 2c having a predetermined size in a region located substantially opposite to the gas suction port 2b provided in the heater housing chamber 24 with respect to the heater 21. The gas sucked into the gas circulation chamber 2 from the gas suction port 2b is blown out from the gas outlet 2a through the gas suction port 2b, the heater housing chamber 24, the communication hole 2c, and the blower housing chamber 25 in this order. is there. The communication hole 2c is provided in the above-described part because the gas sucked into the gas circulation chamber 2 is sufficiently heated by the heater and then sucked into the heated gas circulation blower 22 so that the gas is efficiently supplied. This is for heating. Reference numeral 26 denotes a catalyst filter that mainly removes volatile organic compounds called VOCs among impurities (flux).

  The gas circulation chamber 2 ′ attached to the cooling zone ZZ is different from the gas circulation chamber 2 of the heating zone Z in that there is a cooler instead of a heater, but the other configurations are almost the same, so the detailed description thereof will be omitted. Description and illustration of the internal structure are omitted.

  In addition, in this embodiment, as shown in FIGS. 1, 2, and 5, the gas is sucked from the predetermined heating zone Z, the impurities contained in the gas inside thereof are removed, and the gas after the impurity removal is the same. Alternatively, a cooling circuit 4 for returning to another heating zone Z is provided.

  The cooling circuit 4 includes a cooling gas flow channel 41 having a gas suction end 4a opened to the predetermined heating zone Z and a gas discharge end 4b opened to each gas circulation chamber 2, and the cooling gas flow channel 41. A cooler 42 that cools the gas provided and circulates and liquefies and removes impurities in the gas, and a cooling gas flow path 41 downstream of the cooler 42 and pumps the gas. An adjustment for adjusting the flow rate of gas discharged from the gas discharge end 4b provided in the vicinity of each gas discharge end 4b of the second blower 43 (hereinafter also referred to as the cooling gas circulation blower 43) and the cooling gas flow path 41. And a valve 44. Further, the cooling gas passage 41 has its gas discharge end 4b opened to the gas circulation chamber 2 'of each cooling zone ZZ, and is similarly provided with a regulating valve 44'.

  The heating zone Z in which the gas suction end 4a of the cooling gas flow path 41 is opened is a heating zone Z whose set temperature is higher or lower than a predetermined level than the preceding heating zone Z by a predetermined level. Here, as shown in FIG. 1, the gas suction ends 4a are opened in the heating zones Z (1), Z (4), and Z (6), respectively. The gas suction end 4a is opened at such a location because when the set temperature of the heating zone Z is higher than that of the preceding heating zone Z, the flux is vaporized from the solder. In the opposite case, the gaseous flux contained in the gas may be liquefied or solidified at the boundary. Therefore, this liquefied or solidified flux (mainly resin component) is effectively removed. It is to do. The reason why the gas suction end 4a of the cooling gas passage 41 is not opened in all the heating zones Z is that the gas flow is disturbed, and there is a possibility that the effect of non-interference between the heating zones Z cannot be obtained. is there.

Each gas circulation chamber 2 is provided with a port for connecting the gas suction end 4a of the cooling gas flow path 41, so that the gas suction end 4a of the cooling gas flow path 41 can be set according to the temperature setting. It can be replaced with another gas circulation chamber 2 or can be added or deleted.
The flow rate adjusting valves 44 provided at the gas discharge ends 4b of the cooling gas flow channel 41 are, for example, electromagnetic valves, and are automatically controlled by the control unit 9 described later.

  As shown in FIG. 5, the cooler 42 is provided with a wall body in a maze shape and has a predetermined flow path resistance, and the wall body is cooled with a liquid such as water. Of the formula. In this embodiment, the gas inlet port 42 a and the gas outlet port 42 b of the cooler 42 are provided below the opening of the gas discharge end 4 b in the lower gas circulation chamber 2 to be liquefied and accumulated in the cooler 42. The impurities that are present are prevented from returning to the gas circulation chamber 2 or the substrate passage area AR in the event of an unexpected power failure.

  The control unit 9 (shown in FIG. 1) is a so-called computer including a CPU, a memory, an AD converter, an I / O channel, a display, a keyboard, and the like, and a temperature sensor (illustrated) provided in each heating zone Z. Output the control signal to the control valve 44 and the heater 21 so that the actually measured temperature indicated by the output signal approaches the preset temperature in each heating zone Z. To control them. Here, the temperature sensor is provided in the gas outlet 2a.

  By the way, when the two control means (the heater 21 and the adjusting valve 44) are controlled as described above, the temperatures of the respective heating zones Z are independently maintained with high accuracy and stability even though they are in communication with each other. On the other hand, the two control means may compete to cause a loss. For example, the control valve 44 is greatly opened and the cooling function is activated, and the output of the heater 21 is controlled to be high. In this state, the temperature is maintained, but the energy loss is significant.

Therefore, in this embodiment, in order to eliminate the above-described problems, the control unit 9 controls the temperature of each heating zone Z as follows. This control is performed by the cooperation of the CPU and its peripheral devices according to a program written in the memory.
<Start-up during production>
First, the operation relating to temperature control until the reflow apparatus is started and produced (substrate reflow) will be described below with reference to FIG.
First, the control unit 9 receives an input of production conditions (reflow conditions) including a set temperature of each heating zone Z from an operator (step S1).

  Next, in the initial state, that is, in the state where all the adjustment valves 44 of each heating zone Z are closed, the adjustment valve 44 ′ of the final cooling zone ZZ is closed, the gas circulation in the cooling zone ZZ is stopped, etc. The heated gas circulation blower 22 in the heating zone Z is driven at a predetermined constant rotation (step S2).

  And the temperature feedback control by the heater 21 of each heating zone Z is started (step S3). In detail, as shown in FIG. 7, this control changes the ON / OFF ratio of the heater 21 in accordance with the deviation between the set temperature and the actually measured temperature. If the set temperature is high, the ratio of the ON state increases correspondingly, and if the set temperature is low, the heater is turned off (steps SA1 to SA4).

  At the time of start-up, since the temperature in the furnace starts from a low state, it waits for a predetermined time for the temperature to rise due to the operation of the heater 21 described above (step S4). Thereafter, the heater 21 is continuously driven by the temperature feedback control shown in FIG. 7 unless there is an error.

Next, the controller 9 determines whether or not there is a heating zone Z in which the actually measured temperature does not reach the set temperature range (step S5). The set temperature range is a constant temperature range including the input set temperature. Here, the set temperature is a range where the set temperature is a lower limit and a temperature higher than that by a predetermined temperature (for example, 2 ° C.).
When there is a heating zone Z that does not reach the set temperature range, error processing such as error display, heater stop, and transport mechanism stop is performed to stop the furnace (step S6).

  Otherwise, the control unit 9 determines whether or not the measured temperatures in all the heating zones Z are within the set temperature range (step S7). And when it exists in a preset temperature range, it transfers to a production start process (step S8). This production start process will be described in detail later.

  On the other hand, when the temperature is outside the set temperature range, that is, when there is a heating zone in which the actually measured temperature is higher than the set temperature range, the second blower (cooling gas circulation blower) 43 is driven at the lowest speed and the adjustment in the heating zone is performed. The opening degree of the valve 44 is increased by one step (steps S9 and S10). In this embodiment, the speed of the cooling gas circulation blower 43 is changed to a plurality of stages (for example, four stages) instead of no step. The minimum speed is the rotation speed of the first stage after the stop. Further, the opening degree of the adjusting valve 44 is changed to a plurality of stages (for example, four stages). The speed of the cooling gas circulation blower 22 and the opening degree of the adjustment valve 44 may be controlled steplessly.

  Then, after waiting for a certain time (step S11), the control unit 9 determines whether or not there is a heating zone in which the measured temperature does not drop, that is, a heating zone Z in which the time change of the measured temperature is positive or zero (step S12). .

  If there is a heating zone Z in which the measured temperature does not decrease, the opening of the adjustment valve 44 in the heating zone Z is increased by one step unless it is fully open (steps S13 and S14), and after waiting for a certain time (step S11). Then, the time change of the actually measured temperature of each heating zone Z is judged again (step S12). When the opening degree of the control valve 44 is fully open, the speed of the cooling gas circulation blower 43 is increased by one step (steps S13, S15, S16), and after waiting for a predetermined time (step S11), the heating zones Z are again measured. The time change of temperature is judged (step S12). If the adjustment valve 44 is fully open and the cooling gas circulation blower 43 is at the maximum speed, it is determined that the temperature cannot be lowered, and the error processing described above is performed (step S6).

  When all the measured temperatures in each heating zone Z are lowered, the controller 9 determines whether or not the output of the cooling gas circulation blower 43 is appropriate, that is, whether or not it is the lowest speed (step S17). .

  When the output is not the lowest speed, the output of the cooling gas circulation blower 43 is decreased by one step, and the process returns to step S11 again. When the output is the lowest speed, it is determined whether or not the opening degrees of all the control valves 44 in the heating zone Z are appropriate, that is, whether the opening is the lowest stage or fully closed (step S19).

  When the opening degree of all the regulating valves 44 is not the lowest stage or not fully closed, that is, when there is a regulating valve 44 whose opening degree is higher than the lowest stage, the opening degree of the regulating valve 44 is decreased by one stage. (Step S20), the process returns to Step S11 again.

  When the opening degrees of all the control valves 44 are at the lowest stage or fully closed, the control unit 9 determines whether or not the actually measured temperatures in all the heating zones Z are within the set temperature range (step S21). If it is within the set temperature range, the process proceeds to the production start process (step S8). If not, it is determined whether or not there is a zone where the actually measured temperature is higher than the set temperature range (step S22).

  And when there exists the heating zone Z whose measured temperature is higher than a preset temperature range, it returns to step S9. On the other hand, when there is no heating zone Z whose measured temperature is higher than the set temperature range, the process returns to step S4.

  In the production start process, as shown in FIG. 8, first, whether the output of the heater 21, the output of the cooling gas circulation blower 43, and the opening of the adjustment valve 44 are appropriate, specifically, whether each is below a certain level. Is determined by the control unit (step S81). For example, if the output of the heater 21 is a certain level or more, that is, the ON time is longer than the OFF time, the heater 21 is lit for a long time, and the cooling gas circulation blower 43 has two or more levels of output, the temperature control However, it is considered that the power is unnecessarily consumed due to the competition with the cooling circuit 4. In this case, error processing is performed (step S6). In addition, since appropriate control is performed in the process leading to the production start processing routine S8, a situation where the heater output or the like is excessively large cannot be considered originally. This step S81 is inserted in a fail-safe manner in order to deal with an unexpected situation.

  If appropriate, the cooling gas circulation blower 43 is driven at the lowest speed, and gas circulation in the cooling zone ZZ is started (steps S82 and S83). Until this point, the gas circulation in the cooling zone ZZ was not performed because when the gas circulation in the cooling zone ZZ is started from the beginning, it takes time until the temperature is stabilized and the production starts. This is because power is consumed wastefully.

  And it waits for a fixed time (step S84), and it is discriminate | determined whether measured temperature in all the heating zones Z exists in a preset temperature range (step S85). If it is within the set temperature range, production, that is, carry-in the substrate and perform reflow (step S86). Then, the process returns to step S84. That is, during substrate production, it is monitored whether or not the measured temperatures in all the heating zones Z are within the set temperature range at regular intervals.

  On the other hand, when the measured temperature in any one of the heating zones Z exceeds the set temperature range, it is determined whether or not the measured temperatures in all the heating zones Z are equal to or lower than the limit temperature (step S87). The limit temperature is a temperature that is higher by a predetermined temperature than the upper limit of the set temperature range. For example, this phenomenon may occur when the furnace outer wall stores heat during a long operation.

If there is a heating zone Z that exceeds the limit temperature, at least the substrate loading is prohibited, the production interruption is displayed on the display (step S88), and the gas circulation in the cooling zone ZZ is stopped (step S89). ), The process returns to step S9. On the other hand, if there is no heating zone Z exceeding the limit temperature, the process directly returns to step S9. Then, temperature lowering control is performed by the above-described adjustment valve 44 and the like.
In addition, when all the adjustment valves 44 are fully closed during the above operation, the control unit 9 opens the adjustment valves 44 ′ in the cooling zone ZZ.
<When changing set temperature>
Next, the operation of the control unit 9 when the set temperature is changed will be briefly described with reference to FIG.

  When the control unit 9 receives a change in the set temperature (step SB1), the control unit 9 stops the gas circulation in the cooling zone ZZ (step SB2). Then, the process proceeds to step S9 and operates in the same manner as described above.

  In this embodiment, a furnace unit 11 that forms one heating zone Z is provided, and a plurality of furnace units 11 are connected to form the furnace 1. Each furnace unit 11 is made of a sheet metal having a substantially rectangular parallelepiped shape, and is connected to the adjacent furnace unit 11 so as to be separable by a connection tool B such as a bolt and nut, although not shown in FIGS. It is. And in order to ensure the airtightness between the furnace units 11, sealing members, such as silicone, are interposed in the connection surface.

  Thus, according to the reflow device 100 according to the present embodiment configured as described above, the opening degree of the cooling control valve 44 is not simply determined from the deviation between the set temperature and the actually measured temperature, but the time variation of the actually measured temperature is changed. Since the control valve 44 is driven early by monitoring this, quick and stable temperature control of each heating zone Z becomes possible. Since the temperature can be quickly and stably controlled, the temperature is not excessively lowered, and an unnecessary increase in the output of the heater 21 can be avoided. That is, it is possible to simultaneously reduce the energy consumption as much as possible and improve the temperature controllability of each heating zone Z.

  In addition, a control valve 44 'is also provided in the cooling zone ZZ so that the gas in the cooling circuit 4 is circulated through the cooling zone 44' when not required, so that the internal pressure of the cooling circuit 4 is kept stable to some extent. A gas having a stable flow rate corresponding to the opening degree of the adjustment valve 44 in the heating zone Z can be poured, and temperature control can be suitably performed.

  Furthermore, although each heating zone Z communicates spatially and does not inhibit the passage of the substrate P, gas flow between the heating zones Z is prevented, so that gaseous impurities contained in the gas are It can be very effectively prevented from flowing into the heating zone Z of different temperatures, liquefying or solidifying, and accumulating in the furnace 1. In addition, since the gas flow between the heating zones Z can be suppressed in this way, the temperature effect of the adjacent heating zones Z is reduced as much as possible, and the temperature interference between the heating zones is reduced as much as possible. The temperature of the zone Z can be controlled independently and stably and quickly. As a result, it is possible to accurately create a profile that gives a temperature difference between the heating zones Z, and it is possible to effectively reduce ΔT (1/2 to 1/3 as compared with the prior art). Further, it is possible to create a precise profile in which the number of heating zones is increased to reduce the temperature difference between adjacent heating zones. Furthermore, since the gas only circulates in the furnace 1, so-called ductlessness can be achieved, and impurity discharge to the outside can be reduced as much as possible.

  Further, since the impurity removal circuit 4 is connected only to the heating zone where the flux is generated, efficient impurity removal can be performed, and the impurity removal circuit 4 is a closed circuit and is ductless. The structure can be maintained.

  In addition, since the furnace 1 is formed of the furnace unit 11 having the same shape, it is possible to standardize parts by unitization, and the reflow apparatus 100 having various heating zone stages can be easily manufactured. Further, even if the number of heating zones is increased, the temperature control in each heating zone Z can be reliably performed as described above, so that it is possible to create a gentle curve profile that could not be achieved conventionally.

The present invention is not limited to the above embodiment. For example, as shown in FIGS. 10 and 11, as the furnace unit 11, a first furnace unit 11 (a) that forms two heating zones, and a second furnace unit 11 (b) that forms three heating zones, If the two types are prepared, the two standard products can be used for reflow apparatuses of any length, and manufacture is easier than a furnace unit having a single heating zone. In FIG. 6, symbol B is a connector such as a bolt and nut for connecting to the adjacent furnace unit 11, and symbol S is a seal such as silicone for ensuring airtightness with the adjacent furnace unit 11. It is a member.
In addition, it goes without saying that the present invention can be variously modified without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Reflow apparatus Z ... Heating zone ZZ ... Cooling zone 1 ... Furnace 11 ... Furnace unit 2 ... Gas circulation chamber 21 ... Heater 22 ... Blower 23 ... -Partition wall 24 ... Heater storage chamber 25 ... Blower storage chamber 2a ... Gas outlet 2b ... Gas inlet 2c ... Communication hole 3 ... Gas separation plate 4 ... Impurities Removal circuit 41 ... cooling gas flow path 42 ... cooler 43 ... blower 44 ... control valve 4a ... gas suction end 4b ... gas discharge end 9 ... control unit P. ..Substrate AR: Substrate passage area

Claims (10)

In a reflow apparatus comprising a furnace in which a plurality of heating zones that can be adjusted to different temperatures are arranged in series, and configured to be soldered by passing a substrate through each of the heating zones,
A gas circulation chamber attached to each of the heating zones, a cooling circuit, and a controller;
The gas circulation chamber has a heater and a first blower for gas circulation inside, and blows out gas from a gas outlet opened in each heating zone, and from a gas inlet opened in each heating zone. Gas inhalation,
The cooling circuit has a gas inlet end opened to a predetermined gas circulation chamber or heating zone and a gas discharge end opened to each gas circulation chamber or heating zone, and a cooling gas passage on the cooling gas passage. A cooler provided, a second blower provided on a cooling gas flow path downstream of the cooler and pumping gas, and a gas flow rate adjusted from each gas discharge end And a control valve,
The controller controls the output of each heater to bring the measured temperature of each heating zone closer to the set temperature range set for each heating zone, and the measured temperature is higher than the set temperature range. For the heating zone, when the measured temperature in the heating zone increases with time, the adjustment valve in the heating zone is driven in the opening direction, while when the measured temperature decreases with time, the heating is performed. A reflow device for driving a regulating valve in a zone in a closing direction. In the reflow apparatus further comprising a cooling zone disposed downstream of the heating zone and a gas circulation chamber attached to the cooling zone, the gas discharge end and the gas suction end of the cooling gas flow path are the cooling zone or its gas In addition to opening the circulation chamber, an adjustment valve for adjusting the flow rate of gas discharged from the gas discharge end is provided,
The reflow device according to claim 1, wherein the control unit opens the adjustment valve in the cooling zone when at least all the adjustment valves in the heating zone are closed.   When the control unit has a heating zone in which the measured temperature is higher than the set temperature range by a predetermined temperature or more, the measured temperature in the heating zone increases with time, and the opening of the control valve in the heating zone is maximum. The reflow device according to claim 1, wherein the output of the second blower is controlled in an increasing direction.   2. The control unit notifies at least that board loading is prohibited when the measured temperature exceeds a limit temperature that is a predetermined temperature higher than a set temperature range during the soldering operation. The reflow apparatus in any one of thru | or 3.   The reflow apparatus according to any one of claims 1 to 4, wherein the cooling circuit has an impurity removal function of liquefying and removing impurities contained in the gas.   The reflow device according to any one of claims 1 to 5, wherein a gas suction end of the cooling circuit is opened to a heating zone having a set temperature different from that of the preceding heating zone.   The reflow device according to any one of claims 1 to 6, wherein the cooler is provided at substantially the same height as or below the lower gas circulation chamber.   A partition wall is provided inside the gas circulation chamber to form a heater accommodating chamber for accommodating a heater and a blower accommodating chamber for accommodating a blower, and the gas inlet provided in the heater accommodating chamber is heated. A communication hole of a predetermined size is provided in a part of the partition wall located on the substantially opposite side across the heater so that gas blows out from the gas outlet through the heater storage chamber, the communication hole, and the blower storage chamber in order. The reflow apparatus according to claim 1, wherein the reflow apparatus is configured.   The reflow apparatus according to any one of claims 1 to 8, wherein the furnace is formed by connecting a plurality of furnace units that form one or a plurality of heating zones, and each furnace unit can be contacted and separated.   The reflow apparatus according to claim 9, wherein two types of furnace units are prepared: a first furnace unit that forms two heating zones and a second furnace unit that forms three heating zones.