JP3247774B2 - Reflow equipment - 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 apparatus used for reflow soldering of a surface mount substrate or the like, curing of an adhesive, and the like.

[0002]

2. Description of the Related Art As shown in Japanese Utility Model Laid-Open No. 5-261, a hot air circulation system including a heater is formed inside a furnace body.
In a reflow device that conveys a work through a position that receives infrared radiation from a heater, a heating method that uses heat conduction from hot air to the work and a heating method that uses infrared radiation heat in combination with the heating method, There is known a reflow device in which a hot air control unit and an infrared control unit arranged in the same are mechanically switched.

[0003] In any of the heating methods, hot air is forcedly convected in the furnace. Therefore, if the temperature of the atmosphere circulated in the furnace is detected by a sensor, the temperature of the atmosphere is compared with a set temperature to turn on the heater. Control was able to be performed for the time being. Hot air heating is suitable for reflow soldering of a surface mount substrate because the entire work can be uniformly heated.

[0004]

However, the heater control based on the ambient temperature is not suitable when the heating method using infrared rays is emphasized. In particular, when the hot air circulation system in the furnace is stopped and the infrared heating method using only infrared radiation heat from the heater is used alone, detecting the ambient temperature has no use.

[0005] Infrared heating can be used for purposes other than reflow (for example, curing of adhesives) because a temperature difference is created between the infrared working surface of the work and the opposite side of the work. It could not be used for applications other than reflow.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is possible to control the hot air heating suitable for reflow soldering of a surface-mounted substrate or the like by using the same reflow apparatus by a simple switching operation, and to control the adhesive. It is an object of the present invention to control infrared heating suitable for curing and the like, and to expand applications of a reflow device.

[0007]

According to the first aspect of the present invention,
A hot air circulation system including a heater is formed inside the furnace body, and in a reflow device that conveys a work through a position receiving infrared radiation from the heater, a heater surface temperature control that is provided on the surface of the heater and detects a surface temperature of the heater An ambient temperature control sensor provided between the heater and the work for detecting an ambient temperature in the furnace; a changeover switch for selecting one of a heater surface temperature control sensor and an ambient temperature control sensor; And a temperature controller for controlling the power supply to the heater based on the temperature detected by the sensor on the side selected by the switch.

According to a second aspect of the present invention, there is provided a reflow apparatus in which a nozzle louver for opening and closing an infrared radiation path from a heater to a work in conjunction with the changeover switch according to the first aspect is disposed between the heater and the work. It is.

[0009]

According to the first aspect of the present invention, when the workpiece being conveyed is heated by hot air, energization of the heater is controlled by a temperature controller while detecting an ambient temperature in the furnace by an ambient temperature control sensor. Then, the atmosphere temperature in the furnace is controlled to the set temperature. When the workpiece is heated by infrared rays radiated from the surface of the heater, the changeover switch switches the ambient temperature control sensor to the surface temperature control sensor, and the surface temperature control sensor detects the heater surface temperature while detecting the heater surface temperature. By controlling the energization of the heater by the controller, the surface temperature of the heater is controlled to the set temperature.

According to the second aspect of the present invention, when hot air heating is selected, the nozzle louver closes the infrared radiation path from the heater to the work, and opens when infrared heating is selected.

[0011]

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

FIG. 1 shows the overall structure of a reflow apparatus.
A furnace body 12 is provided inside the apparatus main body 11, left and right guide plates 13 are provided inside the furnace body 12, and a heating unit 14 is arranged above the guide plate 13.

A lid 16 is provided on the upper part of the apparatus main body 11 by a hinge 15.
The upper furnace body 12a, which is detachable from the furnace body 12 by a connecting member (not shown), is integrally attached to the lid portion 16, and the heating unit 14 (not shown) is connected to the upper furnace body 12a. They are integrally attached by members.

Therefore, when the lid 16 of the apparatus main body 11 is opened, the heating unit 14 is also opened on the guide plate 13,
This is convenient for maintenance of the heating unit 14 and manual adjustment of the amount of infrared radiation.

The heating unit 14 has a plurality of sheathed heaters 22 mounted in a frame 21. The heating unit 14 uses radiant heat of infrared rays radiated from the heaters 22 and forced convection heat generated by hot air passing through the heaters 22. This is a heating device for reflow soldering the surface mount substrate (W) W, and a nozzle louver 23 described below is provided below each heater 22.

A heater surface temperature control sensor (thermocouple) 24 for detecting the surface temperature of the heater 22 and controlling the power supply to the heater 22 to control the heater surface temperature is provided on the surface of the sheathed heater 22. They are integrally contacted.

A work transport conveyor 31 is disposed below the heating unit 14. In the conveyor 31, a pair of left and right conveyor frames 31a penetrate the furnace through openings 32 for loading or unloading workpieces, and endless chains 31b are provided elongated along the left and right conveyor frames 31a, respectively. The work (surface mounting board) W is transported horizontally in a state of being bridged between 31b.

On the upper side of the work transfer conveyor 31, an atmosphere temperature for controlling the furnace atmosphere temperature by detecting the furnace atmosphere temperature between the heater 22 and the work W and controlling the energization to the heater 22 is provided. A control sensor (thermocouple) 33 is inserted.

At the lower part of the furnace body 12, one rotating shaft 34 is provided rotatably and laterally, and a pair of left and right furnace atmosphere circulation blowers (one rotating shaft 34 as a common rotating shaft) is used. Centrifugal blowers) 35 are arranged below the left and right guide plates 13, respectively.

The rotating shaft 34 is driven by a motor 37 via a belt transmission mechanism 36. By controlling the rotation speed of the motor 37, the amount of air in the furnace circulated by the circulation blower 35 is controlled.

The rotating shaft 34 of the circulation blower 35 is
It is rotatably held by bearings 34a and 34b attached to the furnace 11, but at least one side of the furnace body 12 has a circulation blower.
An opening 38 having a slightly larger diameter than the fan outer diameter of 35 is provided, and this opening 38 is closed by a detachable closing plate 39, so when maintenance is necessary, the bearing 34b on the opening 38 side is provided. Remove the mounting part 34c and the closing plate 39 of the
By pulling out from the bearing 34a on the opposite side, the circulating blower 35 integral with the rotating shaft 34 can be easily removed from the opening 38 to the outside, making it easy to replace the circulating blower 35 and clean the inside of the furnace. I can do it.

The atmosphere in the furnace sucked into the left and right circulation blowers 35 from the center of the furnace is discharged between the left and right inner wall surfaces of the furnace body 12 and the left and right guide plates 13 and passes through the passage therebetween. It rises, descends from the upper part of the heating unit 14, is heated and heated by the heater 22, is accelerated through the nozzle louver 23, is sprayed on the work W, and the solder paste of the work W is removed from the high-temperature atmosphere. It reflows by heat conduction and is sucked into the left and right circulation blowers 35 again.

In such a pair of left and right hot air circulation systems, the wind generated from the peripheral surfaces of the left and right circulation blowers (centrifugal blowers) 35 rotated by the rotating shaft 34 provided horizontally below the furnace is: Since it has directionality in a direction perpendicular to the rotating shaft 34, it is blown upward in the open furnace and is not swirled in the horizontal direction. In addition, since the pair of left and right circulation blowers 35 are equally rotated at the same speed and in the same direction by the common rotating shaft 34, symmetrical hot air convection is formed in the furnace, and the work transport conveyor 31 draws the paper surface of FIG. The right and left surfaces of the work W conveyed in the direction perpendicular to the vertical direction are uniformly heated.

Next, as shown in FIG. 2, the heating unit 14 includes a plurality of sheathed heaters 22 arranged at predetermined intervals in the frame 21, and rectifying plates 41 on both sides of each heater 22. The nozzle louver 23 is provided below the heater 22 and the current plate 41.

In the nozzle louver 23, an infrared transmitting portion 42 is provided below each heater 22, and a pair of rotating shafts 43 are arranged with the infrared transmitting portion 42 interposed therebetween. A hot air control body 48 facing each other between the adjacent rotating shafts and an infrared control body 49 facing each other via the infrared transmission part 42 are attached. Each rotation axis
Reference numeral 43 has a regular hexagonal cross section at a portion where the hot air control body 48 and the infrared control body 49 are mounted, but is rotatably fitted to the frame 21 at a circular cross section.

A rotating shaft 43 located at the lower right of FIG.
Are integrally attached to each other, and each arm 44 is rotatably mounted on a common interlocking link 45. In addition, the rotary shaft located at the lower left of FIG.
Arms 43 indicated by two-dot chain lines are integrally attached to 43, and each arm 46 is also rotatably mounted on a common interlocking link 47.

When one rotation shaft 43 is rotated by a reversible motor (not shown) and the rotation is transmitted to an adjacent rotation shaft by a gear or the like and rotated in the opposite direction, the one interlocking link 45 and the other interlocking link 45 are rotated. The link 47 moves in the opposite direction, and the rotating shafts 43 of the group having the arm 44 and the rotating shafts 43 of the group having the arm 46 rotate in opposite directions by the interlocking action of the links 45 and 47. I do. Accordingly, the opposing hot air controllers 48 are rotated in opposite directions to open and close, and the opposing infrared controllers 49 are also rotated in opposite directions to open and close.

The hot air controller 48 functions as a hot air jet nozzle by rotating in a direction in which the infrared controllers 49 rotate in a direction in which the infrared controllers 49 rotate in a direction in which they are closed. The infrared controller 49 shields infrared rays emitted from the heater 22 in the closed state.

Next, as shown in FIG. 3, the control system of this reflow device is such that a sensor contact switching relay 52 is connected to a switch 51 for switching between infrared heating and hot air heating. Either the heater surface temperature control sensor 24 or the ambient temperature control sensor 33 is selected, and energization to the heater 22 is controlled via the temperature controller 53 based on the temperatures detected by these sensors 24 and 33.

Further, the changeover switch 51 is connected to a drive motor 37 for the blower 35 for circulating the furnace atmosphere and a reversible motor 54 for driving the rotating shaft 43 of the nozzle louver 23. The atmosphere circulation blower 35 (drive motor 37)
The operation is started by switching the changeover switch 51 to hot air heating, and is stopped by switching to infrared heating.
The rotation direction of the reversible motor 54 of the nozzle louver rotation shaft 43 is determined by the changeover switch 51.

Next, the operation related to the switching of the heating method will be described.

First, when the changeover switch 51 is switched to the infrared heating side, the circulation blower 35 is stopped, and the contact surface switching relay 52 controls the heater surface temperature control sensor 24.
Are selected, and based on the surface temperature of the heater 22 detected by the sensor 24 and the set temperature set in the temperature controller 53, the temperature controller 53 controls the energization of the heater 22, By controlling the surface temperature of the workpiece 22, the amount of infrared radiation determined by the heater surface temperature is controlled, and the surface side of the work W is heated only by the infrared radiation heat.

In this infrared heating, the rotation direction of the motor 54 is controlled by the changeover switch 51, and the rotary shaft 43 of the nozzle louver 23 is driven in the direction in which the infrared control body 49 opens as shown in FIG. Infrared IR radiated from the heater 22 is applied to the work via the infrared transmitting section 42.

In this infrared heating using infrared radiation heat, reflow soldering of the work is also possible. However, when it is desired to provide a temperature difference between the infrared radiation surface side and the opposite side (between the upper and lower surfaces) of the work during heating. For example, it is effective when the adhesive applied to the work is cured.

On the other hand, when the changeover switch 51 is switched to the hot air heating side, the contact of the furnace atmosphere temperature control sensor 33 is selected by the contact switching relay 52, and the furnace atmosphere temperature detected by this sensor 33 and Based on the set temperature set in the temperature controller 53, the temperature controller 53 controls ON / OFF of energization to the heater 22, and drives the motor 37 (FIG. 1) by the changeover switch 51 to control the atmosphere in the furnace. The work is heated by operating the circulation blower 35 and circulating and convection hot air whose temperature is controlled in the furnace.

In this hot air heating, the rotation direction of the reversible motor 54 is controlled by the changeover switch 51, and as shown in FIG. 4B, the infrared control bodies 49 facing each other below the heater 22 are closed. , And shields infrared rays radiated downward from the heater 22. At this time, since the hot air control bodies 48 facing each other are fully opened, the hot air that has passed through the opening between the hot air control bodies 48 facing each other as a hot air jet nozzle is blown onto the work to reflow heat the work. This hot-air heating is suitable for reflow soldering of a surface-mounted substrate or the like because the entire work can be uniformly heated.

[0037]

According to the first aspect of the present invention, one of the sensor for controlling the surface temperature of the heater and the sensor for controlling the ambient temperature is selected by the changeover switch, and the heater is selected by the temperature controller based on the temperature detected by the selected sensor. Since the power supply to the power supply is controlled, a single reflow device can be effectively used by a simple switching operation, and not only can reflow soldering of a surface mount board etc. be performed by hot air heating, but also curing of the adhesive only by infrared heating Can also be performed. That is, one reflow device can be arbitrarily selected and used as a reflow furnace or an infrared heating furnace having a different heating method.

According to the second aspect of the present invention, since the nozzle louver for opening and closing the infrared radiation path is arranged between the heater and the work, only the hot air heating which is not affected by the infrared rays can be performed.

[Brief description of the drawings]

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

FIG. 2 is a sectional view showing a heating unit in the reflow device.

FIG. 3 is a block diagram showing a control system of the reflow device.

FIG. 4 is a sectional view showing an operation of the heating unit.

[Explanation of symbols]

 W Work 12 Furnace 22 Heater 23 Nozzle louver 24 Heater surface temperature control sensor 33 Atmospheric temperature control sensor 51 Changeover switch 53 Temperature controller

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-124727 (JP, A) JP-A 5-261 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05K 3/34 507 B05C 9/14 B23K 1/005

Claims (2)

(57) [Claims] 1. A reflow apparatus in which a hot air circulation system including a heater is formed inside a furnace body, and a work is conveyed through a position receiving infrared radiation from the heater. Sensor for controlling the surface temperature of the heater, a sensor for controlling the ambient temperature in the furnace provided between the heater and the work, and one of the sensor for controlling the surface temperature of the heater and the sensor for controlling the ambient temperature. A reflow apparatus comprising: a changeover switch; and a temperature controller that controls energization of a heater based on a temperature detected by a sensor selected by the changeover switch. 2. A reflow device according to claim 1, wherein a nozzle louver for opening and closing an infrared radiation path from the heater to the work is arranged between the heater and the work in conjunction with a changeover switch for selecting a sensor. apparatus.