JP2000357868A - Reflowing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflowing apparatus capable of uniformly heating a component mounting substrate by adding a near infrared heating system. SOLUTION: In a furnace 34 for receiving component mounting substrates W, a hot air heating means 57 for heating the substrate W with hot air, a far infrared heater 54 for heating with far infrared rays, and a halogen lamp 53 to be near infrared heater for heating with the infrared rays, are provided. It heats various mounted components different in shape, heat capacity, material, color, etc., or heterogeneous members of the same component are uniformly heated with hot air and far and near infrared rays to reduce the temp. difference between the mounted components or the heterogeneous members.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflow apparatus for soldering.

[0002]

2. Description of the Related Art As shown in FIGS. 9 and 10, a conventional reflow apparatus comprises a first preheat furnace 11, a second preheat furnace 12, a third preheat furnace 13, and a reflow furnace 14 each having a furnace body 15. In addition, a rotation transmission mechanism 17 is driven by an external motor 16.
A fan (sirocco fan) 18 driven through the air conditioner and a guide plate 19 for circulating the wind generated by the blower 18 in the furnace body 15 are arranged in the air passage from the upper part to the lower part in the furnace body 15. , A catalyst 21, a heater 22, a rectifying plate 23, a windbreak plate 24, and a far-infrared heater 25 are sequentially arranged.
A chain conveyor 26 for transporting a component mounting board is arranged below the lower side 25.

[0003] The blower 18, the guide plate 19, the heater 22 and the rectifying plate 23 form hot air heating means for heating the component mounting board W in the furnace body 15 by the hot air generated by the blower 18 and the heater 22. I have. The catalyst 21 purifies gas and the like generated from the component mounting board W, and the rectifying plate 23 functions to adjust the flow velocity and directionality of the hot air over the entire surface of the component mounting board.

[0004] The windbreak plate 24 has a lower surface opened as shown in FIG. 10. A plurality of windbreak plates 24 are arranged via a ventilation gap 27. In the first preheat furnace 11 and the reflow furnace 14, A far-infrared heater 25
Is arranged, and the far-infrared radiation emitted from the surface of the far-infrared heater 25 is transmitted to the upper surface of the component mounting board W through the lower opening 28 of the wind-proof plate 24 while preventing the hot air from hitting the far-infrared heater 25 by the windshield 24. Irradiate and heat. In the second preheat furnace 12 and the third preheat furnace 13, it is not necessary to provide the far-infrared heater 25.

[0005]

As described above, the conventional reflow apparatus is provided with the hot-air heating means and the far-infrared heater, and attempts to uniformly heat the component mounting board by using both the hot-air heating and the far-infrared heating. However, in the current heating method, it is reaching a limit to reduce the temperature difference between mounted components or the temperature difference between different members of the same component.

In recent years, lead-free solders, which do not use lead, have recently become the mainstream from the viewpoint of environmental problems. However, lead-free solders have a high melting point, and the mounting parts to be soldered have higher temperatures than before. Therefore, the temperature difference between the mounted components to be heated or the temperature difference between different members of the same component tends to spread, and it is increasingly difficult to uniformly heat the component mounting board.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a reflow apparatus capable of heating a component mounting board more uniformly by adding an unconventional heating method. is there.

[0008]

A first aspect of the present invention provides a furnace body for receiving a component mounting board, hot air heating means for heating the component mounting board in the furnace with hot air, and a component in the furnace body. The reflow apparatus includes a far-infrared heater for heating a mounting board with far-infrared rays and a near-infrared heater for heating a component mounting board in a furnace with near-infrared rays.

The hot air, the far infrared rays, and the near infrared rays uniformly heat various mounted parts having different shapes, heat capacities, materials, colors, or the like, and different materials of the same part, thereby obtaining a temperature difference between the mounted parts or a foreign material. Reduce the temperature difference between members.

According to a second aspect of the present invention, in the reflow apparatus according to the first aspect, the plurality of windshields having a concave cross section opened on the side facing the component mounting board form a ventilation gap in the transport direction of the component mounting board. A far-infrared heater is fitted inside each windbreak plate, and a near-infrared heater is arranged upstream of the ventilation gap.

A far-infrared heater is fitted inside each windbreak plate, and a near-infrared heater is arranged upstream of the ventilation gap between each windbreak plate, so that the far-infrared heater and the near-infrared heater have a high density. Can be arranged.

According to a third aspect of the present invention, in the reflow device according to the first aspect, the plurality of windproof plates having a concave cross section opened on the side facing the component mounting board form a ventilation gap in the transport direction of the component mounting board. One of a far-infrared heater and a near-infrared heater is provided inside each windbreak plate.

By providing either a far-infrared heater or a near-infrared heater inside each windbreak plate, it is possible to prevent hot air heating, far-infrared heater heating, and near-infrared heater heating from affecting each other. Then, each heating is easily adjusted.

According to a fourth aspect of the present invention, in the reflow apparatus according to any one of the first to third aspects, a halogen lamp is used as a near-infrared heater.

The component mounting board is heated by the near infrared rays emitted from the halogen lamp, and the inside of the furnace is illuminated to monitor the reflow state of the component mounting board.

According to a fifth aspect of the present invention, there is provided a reflow apparatus according to the fourth aspect, wherein the halogen lamp has a long glass tube and one surface of the glass tube opposite to a surface facing the component mounting board. And a reflection film provided on the substrate.

The reflecting film on one side of the glass tube provides
The irradiation of near-infrared light toward the reflection film is corrected toward the component mounting board, thereby preventing excessive heating.

According to a sixth aspect of the present invention, in the reflow apparatus according to the fourth or fifth aspect, the halogen lamp includes:
The supply voltage can be adjusted.

By variably adjusting the voltage supplied to the halogen lamp, the wavelength band of near-infrared light emitted from the halogen lamp is changed according to the component mounting board.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS.

FIGS. 1 to 7 show an embodiment.
As shown in FIGS. 2 and 3, a first preheating furnace 31, a second preheating furnace 32, and a reflow furnace 33 are sequentially arranged in the transport direction of the double-sided component mounting board W.

In the first preheat furnace 31 and the reflow furnace 33, as shown in FIG. 1, a blower (sirocco fan) 35 for generating hot air and a blower 35 for generating hot air are generated in the furnace body 34. Guide plate for circulating wind in furnace body 34
The heater 36 and the heater mounting plate 37 are provided symmetrically in the furnace body 34.

As shown in FIG. 1, the hot air generating blower 35 has rotating blades 42 disposed in symmetrically formed concave portions 41 at the lower portion of the furnace body 34, and a motor installed on the outer surface side of the furnace body 34. External motors 45 on the right and left sides are respectively attached to the opening 43 for use via a mounting plate 44, and the rotation shafts of these motors 45
The rotating blades 42 are directly attached to the respective 46.

The guide plate 36 is provided with a central space 47 in the furnace communicated with the suction port 42a side of the rotary blade 42 and a wind discharged from the peripheral surface side of the rotary blade 42 along the left and right side walls of the furnace body 34. The furnace atmosphere circulation space 48 for guiding to the center of the furnace body
The compartments are formed symmetrically inside.

An air heater (seeds heater) 51 for heating an inert atmosphere such as air or nitrogen gas forcedly circulated in the furnace is provided in a central air passage from the upper part to the lower part in the furnace body 34. A rectifying plate 52 such as a punching plate (perforated plate) for uniformizing the flow rate of the heated inert atmosphere throughout the furnace, and a component mounting board W in the furnace body 34 of 760-30.
A halogen lamp 53 as a near-infrared heater for heating with near-infrared light having a wavelength of 00 nm, and a far-infrared heater 54 for heating the component mounting substrate W in the furnace body 34 with far-infrared light having a wavelength of 50 to 1000 μm are sequentially provided. A chain conveyor for transporting component mounting boards is located below these heaters.
55 are arranged.

A thermocouple for temperature detection is disposed above the atmosphere heater 51 and below the far-infrared heater 54, respectively. 56 is wiring for the thermocouple.

The blower 35 for generating hot air, the guide plate 36, the atmosphere heater 51 and the rectifying plate 52 are provided by the blower 35 for generating hot air.
And the furnace air 34 generated by the hot air generated by the atmosphere heater 51.
Hot air heating means 57 for heating the component mounting board W from above
Is formed.

As shown in FIGS. 2 and 3, a first preheat furnace 31, a second preheat furnace 32, and a reflow furnace 33 are provided.
A plurality of windshields 58 having a concave cross-section facing the component mounting board W and having an open lower side are arranged in the conveying direction of the component mounting board W with a ventilation gap 59 therebetween.

In the first preheating furnace 31 and the reflow furnace 33, the halogen lamp 53 is disposed upstream of the ventilation gap 59, and the far-infrared heater 54 is
It is fitted inside 58. That is, the halogen lamp 53 is provided in an upper stage, and the far-infrared heater 54 is provided in a lower stage.

As described above, by disposing the halogen lamp 53 upstream of the ventilation gap 59 between the windshields 58 and fitting the far-infrared heater 54 inside each windshield 58, a constant substrate transport distance can be achieved. At a time, the halogen lamp 53 and the far-infrared heater 54 can be arranged at a high density.

As shown in FIGS. 2 and 3, the halogen lamp 53 and the far-infrared heater 54 include a first preheat furnace 31 which requires a large amount of heat to raise the substrate temperature.
Although it is provided in the reflow furnace 33 which requires a large amount of heat for reflow heating, it is not provided in the second preheat furnace 32 which only needs to have a heat amount that can maintain the preheat temperature. The second preheat furnace 32 is provided with only hot air heating means 57.

In FIG. 3, the first preheat furnace 31 and the second
An exhaust port for ventilating the atmosphere in the furnace is provided between the preheat furnace 32 and between the second preheat furnace 32 and the reflow furnace 33.
There are 60 each.

As shown in FIG. 4, the upper part 34a of the furnace body 34
Is provided to be openable and closable like a flip-up door with respect to the lower portion 34b, and a seal member 61 is interposed between them. On the openable upper portion 34a of the furnace body 34, the left and right heater mounting plates 37 are provided via a bracket 62 together with the atmosphere heater 51, and the windproof plate 58 is provided between the heater mounting plates 37. Are mounted, and the halogen lamp 53 is provided between upper cut grooves 63 formed on the upper portion of the heater mounting plate 37.
The far-infrared heaters 54 are respectively fitted between lower cut grooves 64 formed in the lower part of the 37.

Therefore, by opening the upper part 34a of the furnace body 34, all the heaters 51, 53, 54 can be taken out to facilitate maintenance and inspection.

Each windbreak plate 58 has a parallel plate portion 67 formed below an inverted V-shaped speed increasing portion 66 having a pointed end 65 for cutting hot air.
The halogen lamps 53 are arranged between the sharp ends 65 of the respective windshields 58, and the far-infrared heaters 54 are arranged in parallel to the respective windshields 58.
Located within 67.

As shown in FIG. 5, the halogen lamp 53
Is a double-ended shape in which a base 72 is provided at both ends of a glass tube 71 formed in a long length, and an inert gas and a trace amount of a halide are formed inside the glass tube 71 together with a filament 73 between the bases. It is enclosed.

A reflection film 74 is provided on one surface (upper surface) of the glass tube 71 of the halogen lamp 53 opposite to the surface (lower surface) facing the component mounting board. This reflective film
Numeral 74 is a film formed by depositing or plating aluminum or gold on a glass surface.
Irradiates the near-infrared radiation toward the reflective film toward the component mounting board, thereby preventing excessive heating.

The supply voltage supplied to the halogen lamp 53 is adjustable. By variably adjusting the supply voltage, as shown in FIG. The energy can be changed according to the component mounting board.

Returning to FIG. 1, in the furnace body 34 supplied with the component mounting board W of the double-sided mounting type, the halogen lamp 53, the far-infrared heater 54 and the hot air heating means 57
A heating means 81 for heating the upper surface of the component mounting board W is formed, and the lower surface of the component mounting board W is cooled by temperature-controlled cold air during the heating by the heating means 81. Cooling means 82 is provided.

The cooling means 82 is provided between the recesses 41 in the lower left and right portions of the furnace body 34 and is provided with a heat conductive porous member disposed on the opposite side of the heating means 81 via the transport path of the component mounting board W. A cooling plate 83 is provided, and below the cooling plate 83, a cooling blower 84 is provided via a blower guide 85 as a blower for supplying a gas such as air or nitrogen gas serving as cool air to the cooling plate 83. ing. Cooling blower 84
Is a sirocco fan driven by the motor 86.

Here, the hot air heating means 57 includes an atmosphere heater 51 disposed on the transport path of the component mounting board W, a lower side of the transport path of the component mounting board W, one side in the board width direction, and other parts. A hot air generating blower 35 on both sides for symmetrically disposed on the side and sucking hot air heated by the atmosphere heater 51 through the component mounting substrate W and circulating the hot air on the atmosphere heater 51 is provided. 82 cooling plates
83 and cooling blower 84 are blowers 35 for hot air generation on both sides.
It is arranged between.

Therefore, the cooling plate 83 and the cooling fan 84 of the cooling means 82 disposed between the hot air generating fans 35 on both sides can be compactly incorporated in the furnace body 34. In particular, the cooling plate 83, which is a plate-shaped compact cold air temperature control means, can be installed in the furnace body 34 without taking up space.

The cooling means 82 is provided in each of the first preheating furnace 31, the second preheating furnace 32, and the reflow furnace 33, as shown in FIG.

As shown in FIG. 7, in the cooling plate 83, a refrigerant passage 87 for passing a cooling refrigerant is arranged in a meandering manner. This coolant passage 87 may be formed by, for example, forming a meandering groove on one surface of two panels, and overlapping and welding the grooved surfaces.

A coolant such as air, nitrogen gas or water whose temperature has been adjusted to 15 to 20 ° C. by an air cooling device (not shown) such as an air dryer for adjusting the temperature of the coolant to a set value is supplied to the coolant passage 87. Is done. FIG. 2 shows an inlet-side pipe joint 87a and an outlet-side pipe joint 87b of the refrigerant passage 87.

A cooling air outlet 88 is formed in the cooling plate 83 so as to avoid the refrigerant passage 87. This cool air outlet
Reference numeral 88 denotes a slit which is elongated in a direction perpendicular to the transport direction w of the component mounting board as shown in FIG. 7A, or is cooled as shown in FIG. 7B. The small holes are arranged on the entire surface of the plate 83 at a uniform density.

Further, a large number of fins 89 are vertically provided at regular intervals on the upper surface of the cooling plate 83, and the fins 89 straighten the cool air blown out from the cool air blow-off holes 88.

The slit-shaped cold air blow-off holes 88 shown in FIG. 7A are divided into a central one and a two-sided one in terms of plate strength, and are shifted in the substrate transport direction w. Although it is installed, it is formed to be elongated over substantially the entire width of the cooling plate 83 in a direction perpendicular to the transport direction w of the component mounting board. The component mounting board W can be uniformly cooled by the cool air blown out from the cool air blowing holes 88.

Further, since the small-hole-shaped cold-air blowing holes 88 shown in FIG. 7B are arranged at a uniform density so that the distance between the small-hole-shaped cold-air blowing holes 88 is constant, the cold-air blowing holes 88 are arranged at a smaller distance. The blown cool air can uniformly cool the component mounting board W.

Next, the overall operation of the embodiment shown in FIGS. 1 to 7 will be described.

In the first preheat furnace 31 and the reflow furnace 33, the hot air is heated by the hot air such as air or nitrogen gas blown out from the ventilation gap 59 by the speed increasing section 66 of the windbreak plate 58 of the hot air heating means 57. , Any combination of near-infrared heating by near-infrared light radiated from the halogen lamp 53 through the ventilation gap 59 and far-infrared heating by far-infrared radiation radiated from the surface of the far-infrared heater 54, a double-sided mounting component Used together with the mounting board W.

In this case, heating that emphasizes only hot-air heating, heating that emphasizes near-infrared heating only, heating that emphasizes only far-infrared heating, and heating that emphasizes a combination of hot-air heating and near-infrared heating. , Heating that emphasizes the combination of near-infrared heating and far-infrared heating, heating that emphasizes the combination of hot-air heating and far-infrared heating, and heating that evenly performs hot-air heating, near-infrared heating, and far-infrared heating And can be selected.

When the component mounting board W is heated by the near infrared rays emitted from the halogen lamp 53, the inside of the furnace body 34 can be illuminated by the near infrared rays. It can be monitored from outside through a window (not shown) provided on the side of 34.

As described above, the hot air, the far infrared rays, and the near infrared rays uniformly heat various mounted components having different shapes, heat capacities, materials, colors, or the like, and dissimilar members of the same components, thereby obtaining a temperature difference between the mounted components. Alternatively, the temperature difference between different members is reduced.

In other words, depending on the material or color of the mounted component such as an integrated circuit mounted on the printed wiring board via the solder paste, the absorptivity of far infrared rays or near infrared rays, the shape and area receiving hot air, etc. Adjust the balance between infrared heating, near infrared and hot air heating.

For example, the temperature of a resin part such as a package of an electronic component mounted on a substrate is likely to rise due to hot air heating or far-infrared heating, but the metal part such as a lead frame of the same component is heated with hot air or far-infrared heating. In the case of a component mounting board having a large ratio of this metal part, the atmosphere heater 51, The amount of current supplied to the halogen lamp 53 and the far infrared heater 54 is adjusted.

The wavelength band can be changed by variably adjusting the voltage supplied to the halogen lamp 53. For example, the ambient temperature of the halogen lamp 53 can be reduced by decreasing the voltage supplied to the halogen lamp 53. It is also possible to heat the component mounting board only by near-infrared radiation energy without increasing the temperature.

In this way, while the upper surface of the component mounting board W is being heated by the heating means 81, the lower surface of the component mounting board W is simultaneously cooled by the cooling means 82 with air or nitrogen gas. It is cooled by cold air to thermally protect the mounted components on the lower surface.

That is, a cooling plate having thermal conductivity
A cooling plate such as air, nitrogen gas or water whose temperature has been adjusted to 15 to 20 ° C. from a supply source by an air dryer (not shown) or the like is passed through a cooling medium passage 87 in the cooling plate 87.
83 itself is cooled by this refrigerant to keep it in a set temperature range.
Suppress the temperature rise of the air and nitrogen gas passing through, and cool the mounted parts on the lower surface with the cold air of air and nitrogen gas whose temperature has been adjusted to a predetermined temperature range (normal temperature range), and protect it thermally. By preventing reflow of the mounted components soldered on the lower surface side of the component mounting substrate W in advance, the mounting components on the lower surface of the component mounting substrate W are prevented from falling off due to remelting of the solder.

FIG. 8 shows a modification of the essential part of the reflow apparatus, in which a plurality of windbreak plates 58 having a concave cross-section opening on the side facing the component mounting board W are provided with a ventilation gap in the transport direction w of the component mounting board W. 1 to 4 is the same as the embodiment shown in FIGS. 1 to 4 except that the halogen lamp 53 as a near-infrared heater is provided at the same height level inside each windbreak plate 58.
, And a plurality of far-infrared heaters 54 are provided alternately.

As described above, by providing both the halogen lamp 53 and the far-infrared heater 54 inside each windbreak plate 58, hot air heating, near-infrared heating, and far-infrared heating interact with each other ( Mutual heat interference) can be prevented, and the respective heating temperatures can be easily adjusted.

That is, when the temperature of the hot air is
In addition, it is possible to prevent the surface temperature of the halogen lamp 53 and the far-infrared heater 54 from dropping due to the speed of the hot air, etc. Further, mutual interference between the halogen lamp 53 and the far-infrared heater 54 can also be prevented by each windbreak plate 58.

[0063]

According to the first aspect of the present invention, three types of heating methods, hot air heating by hot air heating means, far infrared heating by a far infrared heater, and near infrared heating by a near infrared heater are combined. Accordingly, it is possible to uniformly heat various mounted components having different shapes, heat capacities, materials or colors, or heterogeneous members of the same component, and reduce a temperature difference between the mounted components or a temperature difference between the heterogeneous members.

According to the second aspect of the present invention, the far-infrared heater is fitted inside each windbreak plate, and the near-infrared heater is arranged upstream of the ventilation gap between each windbreak plate. Since the heaters and the near-infrared heaters are arranged at high density, the temperature rise characteristics of the component mounting board can be made smooth.

According to the third aspect of the present invention, since one of the far-infrared heater and the near-infrared heater is provided inside the plurality of windshields, the heating by hot air, the heating by the far-infrared heater, and the heating by the near-infrared heater are performed. Mutual influence can be prevented, and each heating adjustment can be facilitated.

According to the fourth aspect of the present invention, the component mounting board can be heated by near-infrared rays emitted from the halogen lamp, and the inside of the furnace can be illuminated to monitor the reflow state of the component mounting board.

According to the fifth aspect of the present invention, the irradiation of near-infrared light toward the reflection film is corrected toward the component mounting board by the reflection film on one side of the glass tube of the halogen lamp, thereby preventing excessive heating. it can.

According to the sixth aspect of the invention, by variably adjusting the voltage supplied to the halogen lamp, the wavelength band of near-infrared light emitted from the halogen lamp can be variably adjusted according to the component mounting board.

[Brief description of the drawings]

FIG. 1 is a transverse sectional view showing one embodiment of a reflow device according to the present invention.

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

FIG. 3 is a sectional view taken along line III-III in FIG. 1;

FIG. 4 is an enlarged sectional view showing a main part of the reflow device.

FIG. 5 is a sectional view showing a halogen lamp of the reflow device.

FIG. 6 is a characteristic diagram showing a voltage fluctuation characteristic of a halogen lamp of the reflow device.

FIG. 7A is a plan view showing an example of a cooling plate of the reflow device, and FIG. 7B is a plan view showing another example.

FIG. 8 is an enlarged sectional view showing a modified example of a main part of the reflow device.

FIG. 9 is a transverse sectional view showing a conventional reflow device.

FIG. 10 is a sectional view of a conventional reflow apparatus in a component mounting board traveling direction.

[Explanation of symbols]

 W Component mounting board 34 Furnace body 53 Halogen lamp as near-infrared heater 54 Far-infrared heater 57 Hot air heating means 58 Windproof plate 59 Ventilation gap 71 Glass tube 74 Reflective film

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B23K 3/04 B23K 3/04 X (72) Inventor Shoichiro Matsuku 59-1, Kamirose 11-1, Oaza, Sayama City, Saitama F-term in the company Tamura FA system (reference) 5E319 CC33 CC45 CC49

Claims (6)

[Claims] 1. A furnace body for receiving a component mounting board, hot air heating means for heating the component mounting board in the furnace with hot air, a far infrared heater for heating the component mounting board in the furnace body with far infrared rays, A reflow apparatus comprising: a near-infrared heater for heating a component mounting board in a body by near-infrared rays. 2. A plurality of windshields having a concave cross section having an opening on the side facing the component mounting board are arranged with a ventilation gap in the transport direction of the component mounting board, and a far-infrared heater is fitted inside each windshield. The reflow apparatus according to claim 1, wherein the near-infrared heater is disposed upstream of the ventilation gap. 3. A plurality of windshields having a concave cross section having an opening on a side facing the component mounting board are arranged with a ventilation gap in a conveying direction of the component mounting board, and a far infrared heater and a near infrared heater are provided inside each windshield. The reflow apparatus according to claim 1, wherein any one of the following is provided. 4. The reflow apparatus according to claim 1, wherein a halogen lamp is used as the near-infrared heater. 5. A halogen lamp comprising: a long glass tube; and a reflection film provided on one surface of the glass tube opposite to a surface facing the component mounting substrate. Item 5. A reflow apparatus according to Item 4. 6. The reflow apparatus according to claim 4, wherein the halogen lamp has a supply voltage adjustable.