JPH06310848A - Soldering device in stable inert gas atmosphere - Google Patents

Abstract

PURPOSE:To avoid the defective soldering step due to the production of melted solder oxide by erecting baffer plates in the width equal to or exceeding that of the inlet of a preheating zone and the outlet of a cooling zone on the floor inside said inlet and outlet. CONSTITUTION:Baffer plates 2 are erected on the floor inside the carry-in inlet 4 and carry-out outlet 5 in the width almost equal to the whole width of this soldering device 1 in height almost equal to the level of the lower side of an aperture part 3. Within the continuous soldering device for the conventional printed substrate, several baffer plates 2 are erected at the interval of a few cm and stainless steel is preferable as the material thereof in view of the price and forming etc. Through these procedures, outside air can be restrained from running inside thereby enabling the stable inert gas atmosphere in low oxygen concentration to be created. Accordingly, any oxide can not be produced on a melted solder surface thereby enabling any defective soldering step to be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soldering device having an inert gas atmosphere, and more particularly to a soldering device having a stable inert gas atmosphere even when a small amount of inert gas is supplied.

[0002]

2. Description of the Related Art Conventionally, there have been a plane dipping method and a jet method for soldering a printed circuit board in a factory. In either method, the flux is applied to the pattern surface of the printed circuit board and then the soldering side is soldered. It is immersed in the tank for a predetermined time. Since the surface of the molten solder is in direct contact with the air in the soldering equipment that is often used now,
Oxides are generated on the surface of the molten solder. In particular, in a jet soldering device, when molten solder is jetted from a nozzle and flows down, the area in contact with air becomes large, so that oxidation is more likely to occur. When the molten solder is air-oxidized and oxides are generated in this way, this hinders soldering. As a result, the strength of the soldered part is weakened, and the electrical conductivity is impaired. Are often unable to fully exercise their intended function. As a countermeasure for this, a method of manually removing the generated oxides one by one manually is usually practiced. As another method, a method has been proposed in which oxide is not originally generated on the surface of the molten solder. One of them is a method in which oil or wax is floated on the liquid surface of the molten solder in the solder bath to form a coating layer and the contact between the molten solder and air is cut off to prevent oxidation of the molten solder. Further, as another method, a method has been proposed in which the atmosphere around the molten solder is made into a non-oxidizing gas.
(Japanese Patent Laid-Open No. 61-82965, Sho 61-63363)

[0003]

The method, which is commonly used, for periodically removing the oxide generated on the surface of the molten solder cannot completely remove the oxide, so that the soldering failure can be sufficiently eliminated. Cannot be prevented. In addition, with this method, the soldering process must be stopped when performing the oxide removal work, which reduces efficiency, and since this work is performed manually, there is a risk of burns. It's not good for your health. On the other hand, a method of preventing the oxidation of the molten solder by floating oil or wax on the surface of the molten solder to form a coating layer is such that when the liquid surface of the molten solder is stationary, the coating layer of the antioxidant is uniform. Although effective for forming, when the molten solder is jetted from the nozzle as in a jet soldering device, an oxide is generated because the liquid surface of the molten solder cannot be sufficiently covered with this antioxidant, This causes soldering failure. Further, in this method, the oil or wax that is an antioxidant comes into contact with the high-temperature molten solder, so that it deteriorates or deteriorates, becomes black, and the coating layer of the antioxidant is not formed, so that new oil or wax is supplied. Since it becomes necessary, the operation becomes complicated, and the blackened antioxidant causes troubles such as defective soldering. Furthermore, the recently proposed method of performing soldering processing by using an atmosphere around the molten solder as a non-oxidizing gas requires that the soldering apparatus be sufficiently filled with the non-oxidizing gas to keep the oxygen concentration low. However, when performing a soldering process with a continuous type soldering device, a processed product (hereinafter referred to as a work) is continuously carried in and carried out, and a workpiece outside a carry-in port and a carry-out port is carried out. It is difficult to satisfy this condition because air flows in. Recently, with a jet soldering device in which the atmosphere around the molten solder is a non-oxidizing gas, openable and closable plates are attached to the work inlet and the work outlet to prevent the inflow of external air ( JP-A-6
1-82965), when a printed circuit board on which electrical components are temporarily fastened is soldered by this jet soldering device, the printed circuit board hits the opening / closing plate of the work carry-in port and the electrical components are displaced from a predetermined position. May be defective because it is soldered.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and specifically, in a soldering apparatus for soldering in an inert gas atmosphere, the inlet of the preheating zone Baffle plates are installed upright on the inside of the work (hereinafter referred to as the work carry-in inside) and the inside of the cooling zone exit (hereinafter called the work carry-out inside) to suppress the inflow of external air. As a result, a stable inert gas atmosphere with a low oxygen concentration can be created,
No oxide was generated on the surface of the molten solder, so that the soldering failure, which was often caused by the oxide of the molten solder, did not occur at all.

[0005]

As described above, according to the present invention, the baffle plates are erected on the floors inside the work carrying-in port and the work carrying-out port of the soldering device for soldering in an inert gas atmosphere, so that the molten solder It was possible to completely prevent defective soldering due to the generation of oxides. Moreover, since the baffle is erected in a simple structure, the equipment cost is low and maintenance is almost unnecessary. In addition, not only when the soldering process is not performed, but also when the soldering process is performed, there is an advantage that this does not have to be operated at all.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the soldering apparatus (1) according to the present invention with the front cover removed. FIG. 2 is a model diagram showing the flow of the inert gas in the soldering apparatus of the present invention and the state of inflow of external air into the soldering apparatus. As shown in FIG. 1, the baffle plate (2) of the present invention is erected on the floor inside the work loading port (4) and the work loading port (5). The baffle plate (2) has a width substantially the same as the entire width of the soldering device (1), and a height of the opening (3) (which is an inlet and an outlet for the work). Make the position approximately the same as the bottom side. It is more effective that the number of baffle plates (2) is more than one, and it is preferable to set several baffles (2) upright at intervals of several cm in a normal continuous soldering apparatus for printed boards. As the material of the baffle plate (2), any material that does not corrode to the gas generated from the flux and that has heat resistance can be used, but among them, stainless steel is particularly preferable in view of price and moldability. In the soldering device (1) in which the baffle plate (2) is erected, external air is blocked by the baffle plate (2) from flowing into the soldering device as shown in FIG. In addition to the small amount of air flowing into the soldering device, the inflow of inert gas from the soldering device is suppressed by the external air existing in the vicinity of the opening (3). The oxygen concentration can be kept low, and the amount of inert gas supplied can be small. Examples of the inert gas that can be used in the present invention include N ₂ and A that are usually referred to as an inert gas, and CO ₂ and H ₂ that are usually referred to as a reducing gas.

[0007]

As described above, according to the present invention, the baffle plates are erected on the floors inside the work carrying-in port and the work carrying-out port of the soldering device for soldering in an inert gas atmosphere. Since the oxide of solder has been eliminated by the invention, soldering defects are drastically reduced and productivity and safety are eliminated because the periodic removal work of oxide of molten solder, which was a problem with conventional soldering equipment, is eliminated. The sex was also improved. Further, in the recently proposed method of coating the molten solder liquid surface with an antioxidant such as oil or wax, it is impossible to prevent the oxidation of the molten solder, particularly in a jet soldering device in which the molten solder is jetted from a nozzle, Although the antioxidant has a problem that it burns at a high temperature and causes a new soldering defect, the present invention has also improved these problems. Further, in the soldering apparatus that has recently been provided with a work entrance and a work exit opening / closing plate, the work such as a component to be soldered may be displaced on the opening / closing plate, but in the present invention, it corresponds to the work. Since there is nothing, this kind of problem does not occur.

[Brief description of drawings]

FIG. 1 is a perspective view of a soldering device of the present invention with a front cover removed.

FIG. 2 is a model diagram showing a flow of an inert gas in the soldering apparatus of the present invention and a situation of inflow of external air into the soldering apparatus.

[Explanation of symbols]

 1 soldering device 2 baffle plate 3 opening (workpiece loading / unloading port) 4 work loading port (preheating zone inlet) 5 work loading port (cooling zone outlet) 6 work transfer facility 7 solder bath 8 preheater

Claims (3)

[Claims] 1. An apparatus for soldering a processed product in an inert gas atmosphere, which comprises a preheating zone for preheating a carried-in processed product and a cooling zone for carrying out a soldered processed product, A stable inert gas atmosphere characterized in that a baffle having a width corresponding to the width of these inlets and outlets or a width greater than that is erected on the floor inside the inlet of the preheating zone and the outlet of the cooling zone. Solder having. 2. A plurality of the baffle plates are provided upright, and the height thereof is substantially the same as the positions of the lower sides of the inlet of the preheating zone and the outlet of the cooling zone. Soldering equipment. 3. The soldering device according to claim 1, wherein the inert gas is N ₂ .