JPH06177532A - Reflow device - Google Patents

Abstract

PURPOSE:To produce symmetric convective flows of hot air inside an oven so as to uniformly heat both sides of workpieces in transit by a method wherein an air flow generated from the circumferential surface of a centrifugal blower is driven upwards in an open space vertical to the rotating shaft of the blower in the oven. CONSTITUTION:A rotary shaft 34 is transversely provided in a lower space of an oven 12, two centrifugal blowers 35 are provided in bilateral symmetry about the center of the oven 12 to the rotating shaft 34 used in common under guide plates 13 laterally provided. As an air flow generated from the circumferential surface of the blower 35 rotated by the rotating shaft 34 has such directivity that it moves vertical to the rotating shaft 34, the air flow is blown upwards in an open space in the oven 12 and restrained from blowing horizontally as whirling. Furthermore, the two blowers laterally provided are rotated at the same speed in the same direction by the common rotating shaft 34, so that a symmetric convective flow of hot air is formed inside an oven.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art As a conventional reflow apparatus, as shown in FIG. 4, a single centrifugal blower 2 is arranged on the central axis of a reflow furnace 1, and the centrifugal blower 2 horizontally generates wind. Guide plate 3 guides the air upward, and the wind that has turned downward in the upper part of the furnace is heated to a reflow temperature or higher by heater 4, and the hot air is applied to work (component mounting substrate) W, and the convective heat is transferred to work W. A reflow device for reflowing the solder paste is known.

[0003]

In this type of reflow apparatus, it is desirable to heat the entire work uniformly.
The wind generated in the horizontal direction from the centrifugal blower 2 on the central axis of the reflow furnace 1 whirls up horizontally in the passage between the left and right guide plates 3 and the inner wall surface of the furnace, and then the left and right guide plates 3 Since it descends while turning between them, the positions and directions of the hot air on the left and right surfaces of the work do not match, and the left and right surfaces of the work are not heated uniformly. This is considered to be one of the causes of defective soldering.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a reflow apparatus capable of uniformly heating the left and right surfaces of a work.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a pair of hot air circulation is provided inside a furnace body, which rises along the left and right inner wall surfaces of the furnace body, merges at the central portion of the furnace body, and descends to heat a work being conveyed. In a reflow device in which a system is formed, a pair of centrifugal blowers having a single rotary shaft horizontally provided in the lower part of the furnace body as a common rotary shaft are respectively arranged under the pair of hot air circulation systems. It is a reflow device.

[0006]

According to the present invention, since the wind generated from the peripheral surface of the centrifugal blower rotated by the rotary shaft laterally installed in the lower part of the furnace has a direction perpendicular to the rotary shaft, the inside of the furnace is opened. It is blown up and does not turn horizontally. Further, the pair of centrifugal fans are rotated at a constant speed and in the same direction by a common rotating shaft. Therefore, symmetrical hot air convection is formed in the furnace, and the left and right surfaces of the work being conveyed are uniformly heated.

[0007]

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

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

A lid 16 is attached to the upper part of the apparatus main body 11 by a hinge 15.
Is attached so as to be openable and closable, and a furnace body upper part 12a separable from the furnace body 12 is integrally mounted on the lid body 16 by a connecting member (not shown), and the heating unit 14 is connected to the furnace body upper part 12a (not shown). It is attached integrally by a member.

Therefore, when the lid 16 of the apparatus 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 infrared irradiation amount described later.

The heating unit 14 has a plurality of sheathed heaters 22 mounted between the left and right portions of the frame 21, and the radiant heat of infrared rays emitted from each heater 22 and each heater.
The heating device reflow-solders the component mounting board by the forced convection heat generated by the hot air that has passed through 22, and an infrared control body 23, which will be described later, is provided below each heater 22. Further, a punching plate (perforated plate) 24 is attached to the upper part of the frame 21 for the purpose of equalizing the amount of air sent to the heater 22.

A substrate transfer conveyor 31 is arranged below the heating unit 14. In this conveyor 31, a pair of left and right conveyor frames that penetrate the inside of the furnace through an opening 32 for loading or unloading a substrate are arranged in parallel, and endless chains are elongated along the left and right conveyor frames. The component mounting substrate W as a work is laid horizontally between the chains and is conveyed horizontally.

Below the substrate conveyer 31, a temperature sensor 33 such as a thermocouple for controlling energization of the heater 22 to control the temperature inside the furnace is inserted.

A rotary shaft 34 is rotatably provided in the lower portion of the furnace body 12, and a pair of left and right centrifugal blowers (sirocco fans) 35 having the common rotary shaft 34 as a common rotary shaft 35 are provided.
However, they are arranged symmetrically below the left and right guide plates 13 with respect to the center of the furnace body. The rotating shaft 34 is driven by a motor 37 via a belt transmission mechanism 36. By controlling the rotation speed of this motor 37, the centrifugal blower 35
Controls the amount of air in the furnace circulated.

The furnace atmosphere sucked into the left and right centrifugal blowers 35 from the center of the furnace is discharged between the left and right inner furnace wall surfaces of the furnace body 12 and the left and right guide plates 13, and a passage between them is provided. Is heated and heated by the heater 22 from the upper part of the heating unit 14 through the punching plate 24, and the infrared control body 23 described later
After being sprayed onto the substrate W, the solder paste of the substrate W is reflowed by the forced convection heat, and again the left and right centrifugal blowers 35
Is sucked into.

In such a pair of left and right hot air circulation systems, the wind generated from the peripheral surfaces of the left and right centrifugal blowers 35 rotated by the rotating shaft 34 provided in the lower part of the furnace body is
Since it has a directionality at right angles to, it is blown up into the open furnace and is not swung up while turning horizontally. In addition, since the pair of left and right centrifugal blowers 35 are 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 left and right surfaces of the substrate W conveyed in the direction perpendicular to the paper surface of FIG.

A perforated nozzle 38 for blowing cold air onto the substrate W is provided at the bottom of the furnace body 12. The blowing of cold air from the multi-hole nozzle 38 is necessary when a low melting point solder is used for the substrate W, when components on the lower surface of the substrate are protected from high heat, when the temperature inside the furnace is forcibly lowered, and the like.

Next, as shown in FIG. 2, in the heating unit 14, the plurality of sheathed heaters 22 are arranged at predetermined intervals in the frame 21, and the straightening plates 41 are provided on both sides of each heater 22. Is provided.

Further, a pair of rotating shafts 43 are arranged below the heaters 22 and one heater is provided with an infrared transmitting portion 42 interposed therebetween.
The infrared control bodies 23 facing each other are attached. Each of the rotating shafts 43 has a regular hexagonal cross section at the mounting portion of the infrared control body 23, but is rotatably fitted to the frame 21 at the circular cross sectional portion.

An arm 44 indicated by a solid line is integrally attached to a rotary shaft 43 located at the lower right of each heater 22, and each arm 44 is rotatably attached to a common interlocking link 45. Further, the rotary shaft 43 located at the lower left of each heater 22 has two
Arms 46 indicated by a chain line are integrally attached, and each arm 46 is also rotatably attached to a common interlocking link 47.

When the interlocking link 45 on one side and the interlocking link 47 on the other side are moved manually or by actuators such as solenoids and air cylinders (not shown) in mutually opposite directions, the infrared control bodies 23 facing each other are moved to each other. The infrared rays emitted from the heater 22 are shielded in the closed state by being rotated in the opposite direction to open and close.

Further, hot air control bodies 48 facing each other on the side opposite to the infrared control bodies 23 are attached to the common rotary shafts 43 provided with the infrared control bodies 23. The hot air control body 48 rotates in a direction in which the infrared control bodies 23 rotate in a mutually opening direction, and thus rotates in a mutually closing direction to control the hot air passing amount.

Then, as shown in FIG. 3A, by opening the infrared control body 23, the infrared IR generated from the heater 22 is applied to the substrate through the infrared transmitting part 42 and is heated by the heater 22. The hot air is blown to the board through the infrared transmitting section 42, and the component mounting board is reflow-heated by using the radiant heat of the infrared IR and the forced convection heat of the hot air together. At this time, the hot air control bodies 48 facing each other are rotating in the direction of limiting the air volume.

Further, as shown in FIG. 3B, the infrared rays radiated downward from the heater 22 are shielded by closing the infrared ray control bodies 23 facing each other under the heater 22. At this time, since the hot air control bodies 48 facing each other are in the fully open state, the component mounting board is reflow-heated by the forced convection heat of the hot air passing between the hot air control bodies 48 facing each other.

As described above, when the infrared control body 23 is closed and heated only by hot air, or when the infrared control body 23 is opened and both infrared radiant heat and forced convection heat are used together, rotation common to the infrared control body 23 is performed. The hot air control bodies 48 attached to the shaft 43 so as to face each other rotate in the mutually opening directions of the infrared control bodies 23, and thus rotate in the mutually closing directions. The amount of hot air passage is controlled so that the amount of hot air passing does not change so much by turning in the direction of opening by the amount of turning in the direction of closing.

[0026]

According to the present invention, since the wind generated from the centrifugal blower rotated by the rotary shaft laterally installed in the lower part of the furnace body has a direction perpendicular to the rotary shaft, the open furnace Since it is blown up inward and is not swung up while turning in the horizontal direction, a pair of centrifugal blowers respectively placed under the pair of hot air circulation systems are driven by a common rotating shaft at a constant speed and in the same direction. Since it is rotated equally to the left and right, symmetrical hot air convection can be created in the furnace, and the right and left surfaces of the work can be uniformly heated and good reflow soldering or the like can be performed.

[Brief description of drawings]

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

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

FIG. 3 is a cross-sectional view showing the operation of the above heating unit.

FIG. 4 is a sectional view of a conventional reflow apparatus.

[Explanation of symbols]

 12 Furnace 34 Rotating shaft 35 Centrifugal blower W work

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Niki Masuda, Inventor Niki 11-11, 591 Kamihirose Higashikubo, Sayama City, Saitama Prefecture Inside the Tamura Corporation Machinery Factory (72) Inventor Nobuhide Abe 591, Kamihirose Higashikubo, Sayama City, Saitama Prefecture No. 11 Inside the Tamura Corporation machine work factory

Claims (1)

[Claims] 1. A reflow apparatus in which a pair of hot air circulation systems are formed inside the furnace body, which rise along the left and right inner wall surfaces of the furnace, merge at the center of the furnace body, and descend to heat a workpiece being conveyed. A reflow device, characterized in that a pair of centrifugal blowers having a common rotary shaft that is provided in the lower part of the furnace body as a common rotary shaft are respectively arranged under the pair of hot air circulation systems.