JP3210537B2 - Reflow soldering method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflow soldering method and apparatus for heating and melting solder previously supplied to a wiring board to perform soldering.

[0002]

2. Description of the Related Art Reflow soldering machines can be roughly classified into:
It can be classified into an infrared heating type reflow soldering apparatus that heats a wiring board by infrared rays and a hot air heating type reflow soldering apparatus that heats a wiring board by hot air.

FIG. 4 is a side sectional view showing a conventional infrared heating type reflow soldering apparatus, and FIG.
It is an excerpt from No. 19 (known example 1). That is,
This is a device for heating the wiring board 1 conveyed by the conveyor 3 in the heating furnace 2 by infrared rays radiated from the planar heater 4 and performing reflow soldering.

[0004] The infrared heating type reflow soldering apparatus has a disadvantage that the temperature of the wiring substrate 1 tends to rise excessively because the amount of radiant heat transferred to the wiring substrate 1 is approximately proportional to the fourth power of the heater surface temperature. Therefore, it is necessary to measure the temperature of the wiring board 1 with the radiation thermometer 5 or the like and adjust the heater power so as to obtain a desired heating profile. By the way, in the technique of the known example 1, a hole 6 for measuring the temperature of the wiring board 1 is provided in the sheet heater 4, and the temperature of the wiring board 1 is measured from the hole 6 using a radiation thermometer. There are features where you are.

FIG. 5 is a side sectional view showing a conventional hot-air heating type reflow soldering apparatus, and FIG.
No. 8 (known example 2). That is, the wiring board 1 transported by the transport conveyor 3 in the heating furnace 11
To the atmosphere (hot air) heated by the heater 12
This is a reflow soldering apparatus for performing heating by spraying in step 3.
In the technique of the known example 2, the infrared controller 1 controls the amount of infrared irradiation between the heater 12 and the wiring board 1.
There is a feature in that 4 is provided to be freely opened and closed.

In a hot air heating type reflow soldering apparatus,
Since the amount of heat transfer to the wiring board 1 is defined by the hot air temperature and the air flow (surface wind speed of the wiring board 1), the heat is not essentially heated to a temperature higher than the hot air temperature, and the risk of overheating is low.
However, in a part covered with a metal having high thermal conductivity, the rate of temperature rise is likely to be high. For this reason, a configuration is employed in which the difference in the heating rate due to the difference in the components is reduced by using the infrared heating together. That is, this is a technique in which the amount of infrared rays emitted from the heater 12 for heating the atmosphere to the wiring board 1 is controlled by the infrared controller 14 so that infrared heating can be used while performing hot air heating.

On the other hand, when both hot air heating and infrared heating are used, a heater 12 for hot air heating and an infrared heater (not shown) for heating a wiring board are separately provided, and power control of each heater is performed. There is also a reflow soldering apparatus configured to adjust the amount of heating. In the case of such a reflow soldering apparatus, the temperature of the hot air blown to the wiring board is detected by a sensor, and the electric power applied to the heater for atmosphere heating is controlled so that the temperature is constant at a target value. Feedback control is not performed on the power applied to the heater, and open control is performed on the target applied power to adjust the amount of infrared radiation. This configuration is based on the technical idea of using infrared heating in an auxiliary manner.

The quantitative analysis of the heating and heat transfer characteristics of the above-described infrared heating type reflow soldering apparatus and hot air heating type reflow soldering apparatus, and the necessity of heating with both hot air and infrared rays are described in the Nikkan Kogyo Shimbun "Surface Mount Technology Reader" (edited by Kenji Ito, June 10, 1993)
The details are also disclosed in P149 to P152 7.2.2 infrared reflow furnace and 7.2.3 hot air reflow furnace of the first edition, the first printing.

[0009]

Problems to be Solved by the Invention Japanese Patent Application Laid-Open No. Hei 6-87068
In the technique disclosed in Japanese Unexamined Patent Publication (Kokai) No. 2 (known example 2), there is an advantage that the same heater 12 can be used for heating the atmosphere and the infrared heating of the wiring board 1. There is a disadvantage that the dose cannot be controlled independently. For example, when the temperature of the heater 12 is increased in order to increase the ambient temperature, the amount of infrared radiation from the heater 12 also increases, and the amount of heat transfer to the wiring board 1 by infrared radiation also increases.

In the technique of separately providing an infrared heater and applying a desired constant power to the infrared heater, when the wiring board 1 is being transported, the surface temperature of the infrared heater is lowered and the infrared heater is not transported. In that case, the surface temperature rises. In addition, the surface temperature of the infrared heater also changes when the amount of hot air or the temperature of hot air is adjusted or changed. by the way,
The amount of heat transferred from the infrared heater to the wiring board is defined as the fourth power of the surface temperature of the infrared heater. Therefore, when the size of the wiring board or the transfer tact is changed, or when the hot air temperature or air volume is adjusted, the infrared heater is heated. The amount of heat transferred from the substrate to the wiring board also changes, and as a result, the ratio of the amount of heat transferred by hot air to the amount of heat transferred by infrared rays changes, making it impossible to uniformly heat the wiring board.

Further, when the surface temperature of the infrared heater changes, the ambient temperature also changes under the influence of the change, so that the electric power applied to the heater for atmospheric heating is controlled so as to keep the ambient temperature constant. Therefore, each time the wiring substrate is transported, the surface temperature of the infrared heater changes, and accordingly, the applied power of the heater for atmosphere heating is controlled in a direction to make the atmosphere temperature constant. Therefore, the amount of heat transferred by the hot air and the amount of heat transferred by the infrared light constantly and unstablely fluctuate, thereby hindering uniform heating of the wiring board and reproducibility of the heating profile.

An object of the present invention is to establish a reflow soldering method which can independently and stably control the amount of heat transferred to a wiring board by hot air and the amount of heat transferred to a wiring board by infrared rays. A reflow soldering machine that achieves an optimum heating profile with uniform heating in response to changes in the size and type of components mounted on the wiring board, etc. It is possible to attach.

[0013]

Means for Solving the Problems Claim 1 according to the present invention.
The invention described in the hot air temperature blow against the wiring substrate or
Controls the amount of heat transferred by convection on the basis of at least one of the air amount by the atmosphere circulating means and controls the radiant heat transfer amount based on the surface temperature of the infrared heater, the blowing rate of the cut <br/>囲気circulation means it is intended to independently control each other blow hits the hot air temperature and the wiring substrate and the surface temperature of the infrared heater and.

According to a second aspect of the present invention, the electric power applied to the detected value of the sensor is suppressed by referring to the detected value of the sensor for measuring the hot air temperature, so that the temperature of the hot air blown to the wiring board is kept constant. controls the temperature, and controls the constant value desired surface temperature of the infrared heater with reference to the detected value of the surface temperature sensor for measuring an infrared heater.

[0015] Further, an invention according to claim 3, a heating furnace and an atmosphere circulating path formed by partitioned by a partition member, and an atmosphere circulating means allowed to circulate while the atmosphere in the atmosphere circulation passage, also, the atmosphere a conveyor for conveying the circuit board across the circulation path, and the infrared heater and the circulation of the atmosphere in the vicinity of at least one surface of the wiring board is transported by the transport conveyor capable disposed, also, the wire when viewed from the substrate reflow constituted by the atmosphere heater which is disposed in an atmosphere circulation path which corresponds to the back side of the partition member
In the soldering apparatus, the atmosphere circulating means includes
As the amount is configured variably, the sensor surface temperature measuring detects the surface temperature of the infrared heater, also provided on its vicinity in the <br/> atmosphere circulating wiring board strikes blow side a sensor for ambient temperature measurement for detecting the temperature of hot air of the atmosphere, and the instruction input unit for setting the surface temperature of the infrared heater, a power control unit for adjusting the power supplied to the infrared heater, the instruction input unit Readings and
A temperature control unit for controlling the power control unit so that both the value and compares the detected value of the surface temperature sensor of the infrared heater are matched, the instruction input section configured to set the ambient temperature, heating the atmosphere A power control unit that adjusts the power supplied to the heater; and an instruction value of the instruction input unit that sets the ambient temperature and a detection value of the hot air temperature measurement sensor. A temperature control unit that controls a power control unit that adjusts power supplied to the heater.

[0016]

[0017]

According to the first aspect of the present invention, the amount of heat transferred from the hot air to the wiring board is defined by the hot air temperature, that is, the ambient temperature, when the speed of the hot air is constant, and is derived therefrom. Conversely, if the hot air temperature is constant,
It is defined by the air flow and is derived by it.

On the other hand, the amount of heat transferred to the wiring board by infrared rays (heat rays) is defined by the surface temperature of the infrared heater and is derived therefrom.

By independently controlling the hot air temperature, the amount of air sent, and the surface temperature of the infrared heater, the magnitudes and ratios of the convective heat transfer amount and the radiant heat transfer amount can be accurately and easily set in accordance with the type of the wiring board. be able to.

Therefore, it is possible to easily obtain a desired heating profile while uniformly raising the temperature of the individual components mounted on the wiring board.

According to the second aspect of the present invention, since the surface temperature of the infrared heater is controlled to a desired constant temperature, the surface temperature of the infrared heater is controlled by the presence or absence of a wiring board, the temperature of hot air, and the amount of air blown. Therefore, the amount of heat transferred to the wiring board by infrared rays can be maintained at a target constant value. Further, by making the surface temperature of the infrared heater constant, it is possible to eliminate unnecessary control operations such as canceling out disturbance factors to the ambient temperature by the infrared heater.

Therefore, the temperature of the hot air blown against the wiring board and the infrared rays to be irradiated are extremely stabilized, and the ratio between the amounts of heat transfer is also very stable. That is, a heating environment with good controllability can be realized. As a result, it is possible to easily obtain a desired heating profile while accurately and uniformly heating the individual components mounted on the wiring board.

According to the third aspect of the present invention, the atmosphere in the furnace is circulated by the atmosphere circulating means and blows against the wiring board conveyed by the conveyor. This circulating atmosphere is heated by an atmosphere heating heater, but the infrared rays radiated from the heater are blocked by the partition member and are not irradiated on the wiring board. Therefore, the circulating atmosphere, that is, the hot air heats the wiring board. On the other hand, the infrared radiation radiated from the infrared heater is applied to the wiring board to heat the wiring board. Of course, in the case where both surfaces of the wiring board are heated by infrared rays, infrared heaters are provided near the respective surfaces to perform infrared heating.

The temperature of the hot air blown against the wiring board is detected by a sensor for measuring the ambient temperature, and the surface temperature of the infrared heater is detected by the sensor for measuring the surface temperature. Then, the temperature control unit controls the power control unit while referring to the sensor output so that the hot air temperature matches the instruction value of the instruction input unit, and the power control unit controls the heater power. Similarly, regarding the surface temperature of the infrared heater, the temperature control unit controls the power control unit with reference to the sensor output so as to match the indicated value of the instruction input unit, and the power control unit controls the infrared heater power. Control.

Therefore, the hot air temperature and the surface temperature of the infrared heater are controlled independently in accordance with the set value of the instruction input section, and the amount of heat transferred to the wiring board by hot air and the amount of heat transferred to the wiring board by infrared rays are independent. Can be controlled and adjusted.

As a result, the type of the wiring board, that is, the mounting amount and the mounting type of the component, whether it is mounted on only one surface or both surfaces, the thermal conductivity and the infrared absorptivity of each mounted component In consideration of the differences, the size of the amount of heat transfer by hot air, the amount of heat transfer by infrared rays, and the ratio of the amount of heat transfer can be optimally adjusted, so that the wiring board can be uniformly and objectively formed. Can be heated.

Further, it becomes possible to adjust the amount of heat transferred by convection by feed air flow, hot air temperature and air volume, and by independently controlling the three parties of the surface temperature of the infrared heater, the amount of heat transferred by convection The size and the amount of radiant heat transfer and the adjustment and control range of the ratio of both are further expanded,
And good.

[0028]

EXAMPLES Next, examples of how the reflow soldering method and the reflow soldering apparatus according to the present invention can be actually embodied will be described with reference to examples.

FIG. 1 is a side sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II of FIG. That is, reference numeral 21 denotes a heating furnace, which constitutes a furnace body 26 from a preheating section 24 composed of two rooms of a heating section 22 and a soaking section 23 and a reflow section 25 composed of one room. The wiring board 1 is transported through the transport conveyor 27 of the wiring board 1, and the wiring board 1 is sequentially heated. In addition,
A labyrinth part 3 in which a labyrinth flow path is formed by a restraint plate 30 on the carry-in entrance 28 side and the carry-out exit 29 side of the furnace body 26, respectively.
1 and 32 are provided.

As shown in FIG. 2, a guide plate 33 as a partition member is provided in each of the chambers 24 and 25 of the furnace body 26 to form an atmosphere circulation path 34, and the atmosphere in the atmosphere circulation path 34 is circulated. As a means, the furnace body 2 is provided by a centrifugal blower 36.
The atmosphere is sucked from the suction port 35 on the lower side of 6, and the atmosphere is refluxed from the reflux path 37 to the upper side of the furnace body 26. The refluxed atmosphere subsequently descends and hits the wiring board 1,
It is configured to be sucked into the centrifugal blower 36. The centrifugal blower 36 is driven to rotate by a motor 38.

The heater 39 for heating the atmosphere is disposed in the reflux path 37 of the atmosphere, that is, in the portion corresponding to the back side of the guide plate 33 when viewed from the wiring board 1, and the infrared heater 40 is provided facing each surface of the wiring board 1. Install it near. The infrared heater 40 is provided with a reflection plate 41, a far-infrared radiation ceramic is coated on a pipe-shaped heater, and the infrared heaters 40 are arranged side by side along the conveyor 27. In the present embodiment, the infrared heaters 40 are arranged on the upper side and the lower side of the wiring board 1 so as to heat both surfaces of the wiring board 1 by infrared rays. However, if only one surface of the wiring substrate 1 needs to be heated by infrared rays, the infrared heater 40 may be provided only on that side.

The temperature of the hot air blown against the wiring board 1 is measured by disposing an ambient temperature measuring sensor 42 near the surface on the side where the hot air blows the wiring board 1, and the surface temperature of the infrared heater 40 is measured by the surface temperature. The measurement sensor 43 is connected to the infrared heater 4
Fix to 0 with a band or the like and measure. In addition, a thermocouple sensor is used for these sensors 42 and 43.

FIG. 3 is a block diagram showing an example of a heater power control system and an air flow control system. The same reference numerals in FIGS. 1 and 2 denote the same parts.

In this figure, 51 is a commercial power supply, 52 is a power control unit of the atmosphere heater 39, 53 is a power control unit of the infrared heater 40, and 54 is power control by detection of the atmosphere temperature measurement sensor 42. A temperature control unit that controls the unit 52; 55 is a temperature control unit that controls the power control unit 53 based on a detection signal of the surface temperature measurement sensor 43;
Reference numeral 56 denotes an instruction input unit to the temperature control unit 54, 57 denotes an instruction input unit of the temperature control unit 55, and 58 denotes a microcomputer system. Reference numeral 61 denotes a rotation speed sensor for detecting the rotation speed of the blower 36, and 62 denotes the motor 3
A motor drive control unit 63 for controlling the number of rotations of the motor 8;
Reference numeral 64 denotes a speed control unit for controlling the speed control unit 2 and an instruction input unit to the speed control unit 63. In addition, the same reference numerals as those in FIG. 2 indicate the same parts.

That is, the surface temperature value of the infrared heater 40 detected by the surface temperature measuring sensor 43 is
In step 5, the power control unit 53 compares the value with an instruction value of an instruction input unit 57 composed of, for example, a potentiometer, so that both values are one value.
Is controlled to control the power supplied to the infrared heater 40.
That is, it constitutes a general feedback control system. The power control unit 53 includes a power control device such as an SSR or an SCR, and the temperature control unit 55 includes a PID control system or the like.

The heater 39 for atmosphere heating provided in the recirculation path 37 is also controlled by the same control system, and the power control unit 52 is designed to blow hot air at a desired temperature designated by the instruction input unit 56 onto the wiring board 1. Control.

The rotation speed value of the blower 36 detected by the rotation speed sensor 61 is compared by a speed control unit 63 with an instruction value of an instruction input unit 64 composed of, for example, a potentiometer. The drive control unit 62 is controlled to control the rotation speed of the blower 36. The motor 3
If the induction motor 8 is used, the drive control unit 6
Speed control can be performed by using an inverter for the second control. Further, a PID control system or the like is used for the speed control unit 63.

Further, a microcomputer system 58 is mounted as required, and the hot air temperature and the infrared heater 40 are installed.
The data of the surface temperature (upper and lower sides) and the air volume are input and stored in advance for each type of the wiring board 1.
In soldering, each instruction input unit 5
Instead of 6, 57, 64, it is also possible to adopt a configuration in which an instruction is given to each of the temperature control units 54, 55 and the speed control unit 63.

Next, the operation will be described.

A control system including the power control units 52 and 53, the temperature control units 54 and 55, and the instruction input units 56 and 57 controls the temperature (hot air) based on the detection values from the temperature measurement sensors 42 and 43. The power applied to each of the heaters 39 and 40 is controlled so that the temperature and the surface temperature of the infrared heater 40 are constant.

That is, these mutually independent control systems independently control the temperature of the atmosphere blown to the wiring board 1, ie, the temperature of the hot air and the surface temperature of the infrared heater 40. Therefore, the amount of heat transferred to the wiring board 1 by hot air and the amount of heat transferred to the wiring board 1 by infrared rays can be controlled and adjusted independently. Further, since the surface temperature of the infrared heater 40 is controlled to be constant, the infrared heater 40 does not act as a disturbance factor to the ambient temperature, that is, the hot air temperature. That is, a heating process that is extremely stable and has good controllability is formed.

Further, a control system comprising a motor drive control unit 62, a speed control unit 63, and an instruction input unit 64
Centrifugal blower 36 based on the detection value from rotation speed sensor 61
The drive of the motor 38 is controlled so that the rotation speed of the motor 38 becomes constant.

Here, an example of electronic components mounted on the wiring board 1 will be described as an example to achieve uniform heating.

For example, SMD SOP IC and QF
In a PIC or the like, its package is made of a black epoxy resin or the like. Therefore, the package itself easily absorbs infrared rays, and the temperature rises quickly with respect to infrared heating.
However, when hot air is blown, the temperature of a package having a large heat capacity rises slowly.

Further, since the electrolytic capacitor is housed in the aluminum case, it reflects infrared rays and its temperature rises slowly with respect to infrared overheating. However, when hot air is blown, the temperature rise of the aluminum case having high thermal conductivity is fast.

Generally, since these parts are mixed,
In order to provide the same heating profile by heating these components in the same manner and to uniformly heat the entire wiring board 1, the surface area and volume of the SOP IC and QFP IC, the surface area and volume of the electrolytic capacitor, The amount of heat transferred by hot air and the amount of heat transferred by infrared rays and the ratio between the two are determined in consideration of the mounting ratio of components and the like, and the hot air temperature and the surface temperature of the infrared heater are adjusted by the instruction input unit.

Further, for example, when there are many components having a large component volume and a large heat capacity, the desired convection heat transfer amount and the desired heating rate can be obtained by increasing the amount of hot air and increasing the surface wind speed of the wiring board 1. Obtainable. In this case, uniform heating is also possible by adjusting the amount of radiation heat transfer.

When the temperature distribution of the wiring board 1 is experimentally observed using thermography and the like, and the respective instruction input units 56, 57, 64 are adjusted and selected so as to eliminate the temperature unevenness, the amount of heat transfer by hot air and The amount of heat transferred by infrared rays and the ratio of both can be easily obtained, and the setting of a heating profile is also easy.

In the reflow soldering apparatus of this embodiment, the heater 39 for atmosphere heating is turned off and the operation of the centrifugal blower 36 is stopped.
If only 0 is operated, an infrared heating type reflow soldering apparatus for controlling the surface temperature of the infrared heater 40 to be constant is obtained. Conversely, if the infrared heater 40 is turned off, a hot air heating type reflow soldering apparatus is obtained. Further, if only the centrifugal blower 36 is operated with both the atmosphere heating heater 39 and the infrared heater 40 turned off, the wiring board 1 can be cooled.

Further, it is possible not only to use infrared heating mainly for hot air heating but also to supplement hot air heating mainly for infrared heating. Etc.) can be formed with a heating process having excellent adaptability to the above.

As described above, the type of the wiring board 1, ie, the mounting amount of the type of the component, whether it is mounted on only one surface or both surfaces, the thermal conductivity of each mounted component, In consideration of the difference in infrared absorptivity and the like, it is possible to optimally adjust the amount of heat transfer by hot air, the amount of heat transfer by infrared rays, and the ratio of the amounts of heat transfer. Heating can be performed with a desired profile.

It should be noted that an acceleration / deceleration mechanism including, for example, a pulley or a belt may be provided between the motor 38 and the centrifugal blower 36, and the amount of air blown may be adjusted by adjusting the acceleration / deceleration ratio.

The atmosphere circulation path 34 may be provided with an orifice mechanism whose opening amount can be adjusted, and the amount of air can be adjusted by adjusting the opening amount.

Further, a wind speed sensor is provided in the atmosphere circulation path 34, and the rotation speed of the centrifugal blower 36 or the acceleration / deceleration ratio of the acceleration / deceleration mechanism is determined based on the wind speed signal obtained from the sensor.
A configuration in which the opening amount of the variable orifice mechanism is adjusted and controlled to a desired value may be adopted.

The purpose of adjusting and controlling the amount of air blown by the centrifugal blower 36 is to adjust and control the speed of hot air on the surface of the wiring board 1.

[0056]

As described above, according to the present invention, there are the following effects corresponding to each claim.

According to the invention of claim 1 of the present invention, the atmosphere in the heating furnace is circulated by an atmosphere circulating means, and the circulating atmosphere is heated by an atmosphere heating heater to make the atmosphere hot air. The wiring board is heated by infrared rays generated from the infrared heater, and the amount of convective heat transfer is controlled based on at least one of the temperature of hot air blown to the wiring board or the amount of air blown by the atmosphere circulating means, and based on the surface temperature of the infrared heater. Control the amount of radiant heat transfer
Since the amount of air blown by the atmosphere circulation means, the temperature of hot air blown to the wiring board, and the surface temperature of the infrared heater are controlled independently of each other, the amount of heat transferred to the wiring board by hot air and the amount of heat transferred to the wiring board by infrared light are independent. Can be controlled and adjusted. That is, the magnitude and the ratio of the two amounts of heat transfer can be accurately and easily set in accordance with the type of the wiring board.

Therefore, it is possible to obtain a desired heating profile while uniformly raising the temperature of the individual components mounted on the wiring board, and to realize a reflow soldering process excellent in uniform heating and heating controllability. be able to.

According to a second aspect of the present invention, the electric power applied to the heater for atmosphere heating is controlled with reference to the detection value of the sensor for measuring hot air temperature, so that the temperature of the hot air blown against the wiring board is maintained at a desired constant temperature. In addition to controlling the power applied to the infrared heater with reference to the detection value of the surface temperature measurement sensor of the infrared heater and controlling the surface temperature of the infrared heater to a desired constant value, the presence or absence of the wiring board In addition, the surface temperature of the infrared heater can be controlled to a constant value irrespective of the ambient temperature and the air flow, so that the amount of heat transferred to the wiring board by infrared rays can be kept at a constant value. Conversely, since the surface temperature of the infrared heater is constant, there is no disturbance factor that the infrared heater gives to the ambient temperature, and the ambient temperature, that is, the temperature of the hot air blown against the wiring board is extremely stabilized.

Therefore, the amount of heat transferred to the wiring board by hot air and the amount of heat transferred by infrared rays can be controlled and adjusted extremely accurately, easily, and stably. As a result, it is possible to obtain the desired heating profile while accurately and uniformly heating the individual components mounted on the wiring board, and to finely and stably adjust the heating uniformity and the reproducibility with good reproducibility. A reflow soldering process that can be performed can be realized.

The invention according to claim 3 provides an atmosphere circulation path formed by partitioning the inside of the heating furnace with a partition member, atmosphere circulation means for circulating the atmosphere in the atmosphere circulation path, and an atmosphere circulation path. A conveyor that conveys the wiring board across the board, an infrared heater that is arranged near at least one surface of the wiring board conveyed by the conveyor so as to enable circulation of the atmosphere, and also viewed from the wiring board. An atmosphere heating heater disposed in an atmosphere return path corresponding to the back side of the partition member; a surface temperature measurement sensor for detecting a surface temperature of an infrared heater; and a surface against which an atmosphere circulating on the wiring board is blown Side, and a sensor for measuring the temperature of the hot air in the atmosphere, which detects the temperature of the hot air, an instruction input section for setting the surface temperature of the infrared heater, and an infrared heater. A power control unit that adjusts the power supplied to the power supply unit; and a temperature that controls the power control unit so that the indicated value of the instruction input unit is compared with the detected value of the surface temperature detection sensor of the infrared heater so that the two values match. A control unit, an instruction input unit for setting an atmospheric temperature, an electric power control unit for the atmospheric heater for adjusting electric power supplied to the atmospheric heater, an instruction value of the instruction input unit, and a detection value of the hot air temperature detection sensor And a temperature control unit that controls a power control unit that adjusts the power supplied to the atmosphere heating heater so that the two values match with each other. And the surface temperature of the infrared heater can be adjusted and controlled independently. It is possible to stably hold the amount of heat transferred to the quantity and infrared by the wiring board,
They can be controlled and adjusted independently accurately and easily.

Therefore, the configuration state of the wiring board (both sides,
Each part of the wiring board can be accurately and stably uniformly heated in accordance with one side, the type of mounted components, the number of mounted components, and the like. In addition, the responsiveness to the change in the heating profile is improved. Further, it is possible to optimally adjust the amount of heat transferred by hot air, the amount of heat transferred by infrared rays, and the ratio thereof in each of the temperature raising section, the soaking section, and the reflow step in the preheating step.

As a result, a reflow soldering apparatus capable of heating each part of the wiring board with an extremely uniform and highly reproducible profile is realized, and high-quality wiring boards can be manufactured.

[0064] Furthermore, atmosphere circulation means, since the air blowing amount is configured to be variable, since hot air velocity in the wiring substrate also becomes possible to adjust and control individually adjust the ratio of the heat transfer amount by the hot air The range can be even wider.

As a result, the responsiveness to the configuration state of the wiring board is further improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing one embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line II of FIG.

FIG. 3 is a block diagram showing a heater power control system.

FIG. 4 is a side sectional view showing a conventional infrared heating type reflow soldering apparatus.

FIG. 5 is a side sectional view showing a conventional hot air heating type reflow soldering apparatus.

DESCRIPTION OF SYMBOLS 1 Wiring board 21 Heating furnace 22 Heating section 23 Heating section 24 Preheating section 25 Reflow section 26 Furnace body 27 Conveyor 31 Labyrinth section 32 Labyrinth section 33 Guide plate 34 Atmospheric circulation path 36 Centrifugal blower 39 Atmospheric heating Heater 40 Infrared heater 42 Ambient temperature measurement sensor 43 Surface temperature measurement sensor 52 Power control unit 53 Power control unit 54 Temperature control unit 55 Temperature control unit 56 Instruction input unit 57 Instruction input unit

Claims (3)

(57) [Claims] 1. An atmosphere in a heating furnace is circulated by an atmosphere circulation means.
The circulating atmosphere is heated by an atmosphere heater.
The atmosphere is heated by hot air, and this hot air is
A reflow soldering method of heating the wiring board by infrared rays generated from the heater, wherein a convection heat transfer amount is controlled based on at least one of a hot air temperature blown to the wiring board or an air blowing amount by the atmosphere circulating means, Further, while controlling the amount of radiant heat transfer based on the surface temperature of the infrared heater, the amount of air blown by the atmosphere circulating means and the temperature of the hot air blown against the wiring board and the surface temperature of the infrared heater are controlled independently of each other. A reflow soldering method characterized in that: 2. An electric power applied to an atmosphere heating heater is controlled with reference to a detection value of a hot air temperature measuring sensor to control a temperature of a hot air blown to a wiring board to a desired constant temperature. 2. The reflow according to claim 1, wherein the power applied to the infrared heater is controlled with reference to a detection value of the surface temperature measurement sensor to control the surface temperature of the infrared heater to a desired constant value. 3. Soldering method. 3. An atmosphere circulation path formed by partitioning the inside of a heating furnace with a partition member, atmosphere circulation means for circulating the atmosphere in the atmosphere circulation path, and a circuit board traversing the atmosphere circulation path. A transfer conveyor for transferring, and an infrared heater arranged so as to enable circulation of the atmosphere in the vicinity of at least one surface of the wiring board transferred by the transfer conveyor, and the partition member viewed from the wiring board. A reflow soldering apparatus having an atmosphere heating heater disposed in the atmosphere circulation path corresponding to the back side.
In the above, the atmosphere circulation means is configured such that the blowing amount is variable.
In addition, a surface temperature measuring sensor for detecting a surface temperature of the infrared heater, and an atmosphere for detecting a hot air temperature of the atmosphere, which is provided at a position near the surface on which the atmosphere circulating on the wiring substrate is blown, and detects the hot air temperature A temperature measurement sensor, an instruction input unit for setting a surface temperature of the infrared heater, a power control unit for adjusting electric power supplied to the infrared heater, an instruction value of the instruction input unit, and a surface temperature of the infrared heater A temperature control unit that controls the power control unit so that the two values match each other by comparing the detection values of the detection sensors, an instruction input unit that sets the ambient temperature, and an electric power supplied to the ambient heating heater. a power control unit of the atmosphere heater to regulate, both values is compared with the detected value of the hot air temperature measurement sensor and indicated value of the instruction input section configured to set the ambient temperature coincides Reflow soldering apparatus for a temperature control unit for controlling the power control unit for adjusting the power supplied to the urchin the atmosphere heater, further comprising a said.