JPH0621639A - Soldering equipment - Google Patents

Abstract

PURPOSE:To obtain a small-sized soldering equipment where the consumption of nitrogen, etc., is suppressed so as to correspond to non-rinsing as a countermeasure against chlorofluorocarbon. CONSTITUTION:The equipment consists of a preheating measures for preheating a workpiece 1 and a soldering means for soldering the workpiece 1 that has been processed through preheating, and inactive gas feed means 10, 11 and 12 are also provided so as to supply a heated inactive gas to the workpiece 1 immediately before and after the completion of soldering in the soldering means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soldering apparatus, and more particularly to a soldering apparatus using a non-cleaning flux that is a CFC countermeasure.

[0002]

2. Description of the Related Art In recent years, the requirement for CFCs to protect the ozone layer has been demanded, and the cleaning method has been reviewed in the flux cleaning in the soldering process of printed wiring boards.

Therefore, for the flux cleaning of the printed wiring board, an alternative chlorofluorocarbon cleaning system or a non-cleaning system has been studied.

In the latter case of soldering a printed wiring board using a non-cleaning method, it is necessary to reduce the residue of the flux. However, the reduction of the residue of the flux causes poor solder wetting, a solder bridge, a fillet defect, etc. Decrease stickiness. Therefore, in order to control the deterioration of the solderability as much as possible, soldering in an inert gas atmosphere is required.

Therefore, for the past few years, from such a background, the reflow (R) using nitrogen (N ₂ ) as an inert gas was used.
Development of an eflow device and a dip (Dip) soldering device is progressing, and practical application of soldering with a low residue flux + N ₂ has begun in an OA equipment substrate or the like which has been conventionally cleaned.

[0006]

The current N ₂ soldering system eliminates the entire Dip (dipping) area from the preheating area after flux application to smooth the bonding action and protect the bonded article from heat shock. Enclose it in an active gas atmosphere, such as a nitrogen atmosphere, to reduce the oxygen concentration to some extent,
Placed on the substrate from the pre-heat process to the Dip process,
It is common to improve solderability by suppressing oxidation of component electrodes and molten solder.

However, Dip in this N ₂ atmosphere
The soldering system can certainly improve the solderability when a low residue, weakly active Flux is used, but it has the following problems.

1) As described above, since the entire area from the preheating area to the Dip area is filled with a nitrogen atmosphere, the soldering apparatus becomes large in size and its cost becomes high.

2) A large amount of nitrogen is consumed, resulting in high running cost.

In view of the above problems, it is an object of the present invention to provide a small soldering apparatus that consumes less nitrogen and is compatible with non-cleaning measures against CFCs.

[0011]

According to the present invention, the above-mentioned problems include preheating means for preheating a workpiece and soldering means for soldering the workpiece that has passed through the preheating means. A soldering apparatus, comprising an inert gas supply means for supplying a heated inert gas to a workpiece immediately before and after completion of soldering by the soldering means. Will be solved by.

In the present invention, the inert gas is preferably nitrogen.

Further, in the present invention, it is preferable that the heating of the inert gas is performed by using the molten solder in the soldering means in terms of downsizing of the apparatus and running cost.

[0014]

The soldering apparatus of the present invention comprises, as shown in FIG. 1, a spray type fluxer 21 having a low residue flux, a preheater 22 for preheating a workpiece, a solder bath 23 and a nitrogen generator 10. In particular, as shown in FIG. 1, in the molten solder bath 3 as a soldering means, immediately before the completion of soldering,
Immediately after that, the structure is such that heated inert gas, for example, nitrogen, can be jetted to the printed wiring board 1 of the workpiece near the so-called peel back area P.

Therefore, according to the soldering apparatus of the present invention, the molten solder is not oxidized in the vicinity of the peel back area P when the soldering is completed, and the atmosphere is heated, so that the solder joint portion and the atmosphere are sharp. Since there is no temperature difference,
Soldering can be completed without losing the fluidity of the solder joint,
Even when a low residue weakly active type flux is used, the fillet is sufficiently formed, there are few defects such as non-wetting and solder bridges, and sufficient solderability can be secured. As a result, the flux residue is reduced, and a reliable uncleaned substrate can be obtained.

Further, the contact characteristic of the checker pin at the time of checking the circuit after mounting can be improved by reducing the residual flux. Further, even when a general RA type (active type) is used, there is a similar effect of improving the solderability, which also contributes to reduction of touch-up (correction) man-hours after soldering.

Moreover, unlike the conventional nitrogen atmosphere soldering method, the solder need only be injected with nitrogen immediately after completion of the soldering, so that the nitrogen consumption amount is small and it contributes to downsizing.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing a structure of a soldering apparatus according to the present invention.

As shown in FIG. 1, the soldering apparatus according to the present invention, which is compatible with non-cleaning as a measure against freon, is a conventional spray type fluxer 2 for low residue flux in a soldered portion.
1. Preheat heater 22 for preheating the workpiece before soldering,
It is composed of a nitrogen injection nozzle 12 for injecting high-temperature nitrogen at the time of completion of soldering, and a solder tank 23 for soldering means having the nitrogen generator 10.

In the soldering apparatus of the present invention shown in FIG. 1, so-called soldering means including a solder bath and a nitrogen generator portion, which are more characteristic of the present invention, will be described with reference to FIG.

In FIG. 2, the printed wiring board 1 is provided with a mounting component 2 as a workpiece to be soldered.

In the soldering means shown in FIG. 2, a known soldering system is provided with a nitrogen generator 10 and a nitrogen supply pipe 11 connected to the device 10, and a nitrogen injection nozzle 12 at the tip thereof.
And an inert gas supply means are provided. The spray nozzle has a large number of tubular holes and continuously sprays nitrogen when the substrate 1 passes through. In FIG. 2, 5a and 5b are respectively a front plate and a variable rear plate that support the jet solder, and 13 is a regulator that detects the amount of nitrogen.

The portion of the nitrogen supply pipe 11 near the portion where the nitrogen injection nozzle 12 is attached once passes through the molten solder (high temperature of 240 to 250 ° C.) in the molten solder bath 3 of the soldering system, and then the molten solder. Is designed to heat the nitrogen. In addition, the tip of the nitrogen injection nozzle 12 is directed to the soldering end portion (peeling back area P) of the printed wiring board, which enables soldering in a nitrogen atmosphere, so that a defective solder joint portion of the mounting component 2, that is, It suppresses formation of soldering defects such as wetting and solder bridge fillet defects.

Although nitrogen is used as the inert gas in this embodiment, argon or the like may also be used.

In the soldering system section shown in FIG. 2, the solder 4 heated and melted is jetted (flowed) through the pump 6, and the solder jet section 4a is provided with the soldered joint section of the mounting component 2 of the printed wiring board 1. This is a contact-type joining system that is dipped and soldered.

[0027]

As described above, according to the present invention,
Compared to the conventional flux-cleaning non-flux-cleaning nitrogen atmosphere soldering device, which consumes less nitrogen, it can be downsized, and the cost of the device itself and the running cost can be reduced. Even when the residual flux is used, unsoldered solder bridges, fillet defects, etc. can be improved and sufficient solderability can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a soldering device of the present invention.

FIG. 2 is a schematic view of an embodiment of the soldering device of the present invention.

[Explanation of symbols]

 1 Printed Wiring Board 2 Mounted Components 3 Molten Solder Tank 4 Molten Solder 4a Solder Jet Section 5a Front Plate 5b Variable Rear Plate 6 Pump 10 Nitrogen Generator 11 Nitrogen Supply Pipe 12 Nitrogen Jet Nozzle 13 Regulator 21 Fluxer 22 Preheat Heater 23 Solder Tank ( Soldering means) P peel back area

Claims (3)

[Claims] 1. Preheating means for preheating a workpiece, and
A soldering device having a soldering means for soldering a work piece that has gone through the preheating means, wherein a heated inert gas is applied to the work piece immediately before and immediately after the completion of soldering in the soldering means. A soldering device comprising an inert gas supply means for supplying. 2. The soldering apparatus according to claim 1, wherein the inert gas is nitrogen. 3. The soldering apparatus according to claim 1, wherein the heating of the inert gas is performed by using the molten solder in the soldering means.