JPH01148459A - Reflow soldering device - Google Patents

Abstract

PURPOSE:To enable reflow soldering without any dispersion of the temp. in the width direction by heating the work to be moved by an infrared ray heater and blowing a hot blast to the same face of the work from the nozzle arranged at the right and left parts of a transfer space. CONSTITUTION:The reflow soldering of a work W is performed by using both of the heating by an infrared ray heater 15 and that by blowing of a hot blast to the work W for the work W sent in an arrow mark direction by a work transfer conveyor 12. In this reflow soldering device nozzles 41, 42 are arranged at the upper and lower, right and left parts of a work transfer space heated by the infrared ray heater 15. The hot blast is blown on the same face of the work W from the right and left directions of the work W from the hot blast injection ports 43, 44 faced to a slanting lower part or upper part respectively pierced on these nozzles 41, 42. The work W is thus heated uniformly and the soldering of high reliability without any thermal stress can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a reflow soldering apparatus using an infrared heater.

(Prior Art) As shown in Japanese Patent Publication No. 61-289697, a reflow method uses a combination of heating by an infrared heater and heating by blowing hot air onto a workpiece conveyed by a workpiece conveyor. There is a soldering device.

This reflow soldering device allows hot air to flow approximately parallel to the direction of movement of the conveyor.

(Problem to be Solved by the Invention) When the temperature of a printed wiring board as a workpiece heated by the infrared heater is measured, when the temperature is about 200°C on both the left and right sides in the direction of movement of the board, the center of the board is part is heated to about 250°C.

Although this variation in substrate temperature can be somewhat corrected by using the heating method using hot air as described in the above-mentioned publication, no significant effect can be obtained.

This is because the hot air is flowed in an orderly manner in one direction (the direction of conveyor movement), and such a flow cannot eliminate temperature variations in the width direction of the substrate.

This variation in heating temperature puts thermal stress on electronic components mounted in the center of the board, reducing the reliability of reflow soldering.

An object of the present invention is to eliminate temperature variations that occur in the width direction of a workpiece by improving the nozzle arrangement and hot air blowing direction.

[Structure of the invention]

(Means for Solving the Problems) In the present invention, the workpiece W transported by the workpiece transport conveyor 12 is heated by an infrared heater 15 and heated by blowing hot air onto the workpiece, so that the workpiece can be reflowed. In a reflow soldering apparatus that performs soldering, a nozzle 41 blows hot air onto the same surface of the workpiece W from the left and right directions with respect to the workpiece transport direction, on the left and right sides of the workpiece transport space heated by the infrared heater 15.
41 or 42.42 are arranged.

(Function) In the present invention, the hot air blown from the left and right nozzles 41.41 or 42.42 collides with the workpiece surface, and the turbulence caused at that time causes the workpiece conveyance space to be heated by the infrared heater 15. The atmosphere is stirred and the temperature of the atmosphere becomes uniform with no variation. In particular, the hot air blown onto the workpiece surface from the left and right directions helps eliminate temperature variations that tend to occur in the left and right directions of the workpiece W.

(Examples) Hereinafter, the present invention will be described in detail with reference to examples shown in the drawings.

FIG. 3 shows an infrared reflow soldering apparatus. In this figure, the motor 11 rotates me
The work to be soldered (print placement! board) is supported and conveyed by the work conveyor 12.

As shown in FIG. 3, above and below the upper linear part of the conveyor 12, there are far-infrared panel heaters 13 used for first stage preheating, and far infrared panel heaters 13 used for second stage preheating. A far-infrared panel heater 14 used for heating, and an infrared heater (quartz heater) 15 used for main heating are arranged between the workpiece loading section 16 and the workpiece unloading section 17. A cooling fan 18 is provided in the workpiece unloading section 17 .

As shown in FIGS. 1 and 2, the infrared heater 15 is attached to a heater body 22 via a mounting plate 21, and the workpiece conveyor 12 is connected to a pair of trowel-shaped guide rails 31. A pair of endless chains 33 are movably provided along the chain 32, and a workpiece (printed circuit board III) W is suspended and supported between the support plate portions 34 protruding from the link plates of the pair of chains 33. There is. Note that one guide rail 31 is provided in a fixed manner, and the other guide rail 32 is provided so as to be movable and adjustable in the width direction (horizontal direction in FIGS. 1 and 2), so that it can respond to changes in the width of the workpiece.

As shown in FIG. 2, on the upper and lower opposing surfaces 35 and 36 of the pair of left and right guide rails 31 and 32, a workpiece conveyance space is provided, which corresponds to the workpiece conveyance space heated by the infrared heater 15. Nozzle 41.4 that blows hot air onto the upper surface of the workpiece W from the left and right directions.
Nozzles 42 and 42 for blowing hot air onto the bottom surface and the bottom surface are respectively attached.

The nozzle 41 for the upper surface of the workpiece has a large number of hot air blowing holes 43 diagonally downward, and the nozzle 42 for the lower surface of the workpiece has a large number of hot air blowing holes 44 diagonally upward. . Each nozzle 41, 42 is formed by a straight pipe with one end closed, and a pipe 46 connected to the other end of the straight pipe via a pipe joint 45 communicates with a hot air generator 47 shown in FIG. has been done. Hot air of 220 to 250° C. supplied from the hot air generator 47 is ejected from the hot air blowing hole 43.44 of the nozzle 41.42.

In this way, the nozzles 41 and 42 are connected to the fixed side guide rail 3.
1 and the movable guide rail 32, so when the width of the workpiece W changes and the movable guide rail 32 is moved and adjusted in the width direction to change the rail spacing on both sides, the left and right nozzle spacing is automatically adjusted. adjusted accordingly.

Then, as shown in FIG. 4, the temperature of the workpiece W is raised to a certain preheating temperature by the far-infrared panel heater 13 in the first stage preheating area 51, and then
The far infrared panel heater 14 in the preheating area 52 of the stage
The preheating temperature is maintained by heating by the infrared heater 15 and the nozzle 41 in the main heating region 53.
The temperature of the workpiece W is raised to about 210°C by heating by blowing hot air from 42, and the workpiece is printed! Cream solder interposed between the No. 11 board and the board-mounted components is melted, and reflow soldering is performed. In FIG. 4, reference numeral 54 indicates an area that is forcibly cooled by the cooling fan 18.

In the main heating area 53 that uses both the infrared rays and hot air,
The hot air blown from the left and right nozzles 41 collides on the upper side of the workpiece W, and the hot air blown from the left and right nozzles 42 collides on the lower side of the workpiece W. The generated turbulence stirs the atmosphere in the workpiece transfer space heated by the infrared heater 15, and the atmosphere temperature becomes uniform without variation.

In particular, the hot air blown onto the work surface from the left and right directions helps eliminate temperature variations that tend to occur in the left and right directions of the work. For example, the left and right parts a1 of the workpiece W shown in FIG.
The temperature difference between b and the center part C is very small as shown by the peak waveform in FIG.

〔Effect of the invention〕

According to the present invention, the nozzles that blow hot air onto the same surface of the workpiece from the left and right directions with respect to the workpiece transport direction are disposed on the left and right sides of the workpiece transport space heated by the infrared heater, so that the atmosphere is unevenly heated by the infrared heater. is agitated with hot air, eliminating temperature variations that occur in the width direction of the workpiece, allowing the entire surface of the workpiece to be heated uniformly, and preventing the risk of thermal stress being applied to electronic components in high-temperature areas that would impair quality. can.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the reflow soldering apparatus of the present invention, FIG. 2 is a sectional view taken along the line II-I in FIG. 1, and FIG.
The figure is a front view of the entire device, and FIG. 4 is a graph showing the temperature profile of the workpiece heated by the device. W... Workpiece, 12... Workpiece conveyor, 15...
Infrared heater, 41.42... nozzle. December 4, 1986

Claims (1)

[Claims] (1) In a reflow soldering device that performs reflow soldering of a workpiece by heating the workpiece conveyed by a workpiece conveyor by heating it with an infrared heater and heating it by blowing hot air onto the workpiece,
A reflow soldering device characterized in that nozzles are disposed on the left and right sides of a workpiece transfer space heated by an infrared heater to blow hot air onto the same surface of the workpiece from the left and right directions with respect to the workpiece transfer direction.