JPH03187291A - Soldering method - Google Patents

Abstract

PURPOSE:To solder excellently without solder bridge or miss by coating, after primary soldering, again with flux, and secondarily soldering. CONSTITUTION:A controller 24 selectively drives or pauses a voltage supply source 22, a motor driver 23 by an output signal of a temperature detector 21 to set a temperature of flux 25 optimally for coating. The air is fed from an air pipe 13 by such temperature management, the flux 25 is bubbled through a bubbling tube 12 with the air to be adhered to a printed board 1. A second flux coating unit 10 composed in this manner is arranged between a primary jet port 6 and a secondary jet port 8 on a solder tank 5 to coat again, after primary soldering, with the flux and to secondarily solder. Thus, excellent soldering is performed without solder bridge or miss.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a method for soldering electronic components, etc., and provides a soldering method that can reliably solder no matter how fine or intricate the parts to be soldered are. For this purpose, a soldering method in which soldering between an automatically transported board and an electronic component mounted on the board is performed multiple times is configured such that flux is applied between each soldering.

[Industrial application field]

The present invention relates to a method for soldering electronic components and the like.

BACKGROUND ART In recent years, the integration of electronic components and the high-density mounting of electronic components on printed wiring boards (hereinafter referred to as printed boards) have been progressing. Along with this, the number of electronic components with complex and detailed shapes is increasing.

It is necessary to ensure electrical continuity between the lead terminals of such electronic components and wiring patterns formed on the printed board, and to securely fix these electronic components to the printed board.

[Conventional technology]

FIG. 3 shows a conventional soldering device. This will be explained below with reference to the same figure. In addition, the same reference numerals throughout the figures represent the same thing.

In the figure, 1 is a printed board, and the board includes a resistor and
Electronic components such as diodes and capacitors are temporarily fixed on one or both sides with adhesive or the like. Reference numeral 2 denotes a carrier, which supports and transports the printed board 1. 3 is a flux coating device, which is a device for coating the back surface of the printed board 1 with flux. Further, as the flux coating device 3, there are generally known types such as a foaming type, a brush coating type, and a spraying type.

4 is solder which is in a melted state by a heater (not shown).

5 is a solder tank for accumulating the solder 4 described above. Reference numeral 6 denotes a primary jet port, where the molten solder 4 is vigorously jetted out by the rotational action of the propeller 7.

A propeller 7 is used to send the solder 4 to the primary jet port 5. Reference numeral 8 denotes a secondary jet port, where the molten solder 4 is gently jetted by the rotational action of the propeller 9. A propeller 9 is used to send the solder 4 to the primary jet port 5.

The printed board 1 transported by the carrier 2 is solder plated according to the following procedure.

1) Apply flux to the back surface of the printed board l using the flux applicator 3.

2) The part to be soldered is excited by a heater (not shown). (Preheating in the figure) 3) - Apply the solder 4 which is vigorously jetted from the next jet port 6 to the part to be soldered. By this application, the solder 4 can be applied even to the details of the electronic components, especially those having complicated and fine shapes.

4) Apply the solder 4, which is gently jetted from the secondary jet port 8, to the part to be soldered. This application ensures soldering.

As mentioned above, soldering using the -order jet (hereinafter referred to as -order soldering) is difficult to achieve due to the complicated shape.
The main purpose of soldering is to solder the parts that are difficult to reach, and soldering using secondary jets (hereinafter referred to as secondary soldering) not only solders the parts that are relatively easy to reach with solder 4, but also ensures soldering. The main purpose is to Naturally, as mentioned above, the secondary jet port 8 is connected to the primary jet port 6.
Solder 4 is supplied more vigorously compared to the above.

[Problem to be solved by the invention]

The printed circuit board to which flux has been applied by a flux application device is preheated and then subjected to second soldering, followed by secondary soldering, but the first applied flux is It soon loses its effectiveness, and when used for secondary soldering, it becomes less effective as a flux.

This caused solder blobs and non-solder adhesion.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a soldering method that can reliably solder no matter how fine or intricate the parts to be soldered are.

[Means to solve the problem]

The main idea of the present invention is to eliminate solder bridges and unsolder by applying flux again and performing secondary soldering after the secondary soldering. That is, as shown in FIG. 1, the soldering method involves soldering multiple times between the automatically transported board 1 and the electronic components mounted on the board 1, in which flux is applied between each soldering. Configure it as follows.

[For production]

According to the present invention, after the secondary soldering, flux is applied again and secondary soldering is performed, so that good soldering is possible without the occurrence of solder bridges or non-solder adhesion.

〔Example〕

FIG. 1 is a configuration diagram of an embodiment of the present invention, and FIG. 2 is a second flux coating device. Embodiments of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, only the second flux coating device 10 is different from the device shown in [Prior Art], and all other configurations are the same. This second flux device W10
The one shown in Figure 2 is adopted. In the figure, 11 is a flux container formed in a cylindrical shape, 12 is a foaming tube made of sintered metal, bisque, etc. provided in the container 11, 13 is an air pipe for feeding air into the foaming tube I2,
14 is a nozzle provided in the container 11 so as to cover the foaming tube 12; 15 is a heater provided on the outer periphery of the container 11;
Reference numeral 6 denotes a heat radiation part formed integrally with the container 11, 17 a cooling fan provided opposite to the heat radiation part 16, and 18 a nozzle 1.
A regulating plate is placed floating from 4 to prevent flux from being applied in excess of a desired amount or to an unnecessary area, 19 is a housing made of a heat insulating material, 20 is a temperature sensor such as a thermoelectric body, and 21 is a temperature sensor. A temperature detection unit that detects the temperature from a detection signal from the sensor 20; 22, a voltage supply source that supplies voltage to the heater 15; 23, a motor drive unit that drives a motor (not shown) included in the cooling fan 17; 24 is a voltage supply source 22 . A control section 25 that controls the motor drive section 23 is a flux. Upon receiving the detection signal from the temperature sensor 20, the temperature detection section 21 detects the temperature of the flux 25. In response to the output signal from the temperature detection section 21, the control section 24 controls the voltage supply source 22. By selectively driving or stopping the motor drive section 23, the temperature of the flux 25 is optimized for application.

Under such temperature control, air is sent from the air pipe 13, and the air passes through the foaming tube 12 to foam the flux 25, which adheres to the printed board 1 and the like.

Here, since these devices are covered with a housing 19 made of a heat insulating material, they are not affected by the heat of melted solder or the like.

Second flux coating device 10 configured as above
By arranging it in the position shown in FIG. 1, it becomes possible to apply flux again after the second soldering and perform the second soldering.

Further, in this embodiment, the flux coating device is of a foaming type, but it may be of a vapor type, a brush coating type, or a spraying type.

〔Effect of the invention〕

According to the present invention, by applying flux after secondary soldering, short circuits due to solder bridges, improper fixation of mounted components due to unattached solder, and failures caused by contact resistance due to insufficient solder adhesion are eliminated. .

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention. Figure 2 shows the second flux coating device, FIG. 3 shows a conventional soldering device. In Figure 1, Ru. ■　－・－・ - 3------・-m--- 4--------- 5・・−−−−−1・− 6・- 7－－－－－－－・−・− − 9・－・・・・・・－ The numbers with symbols are as follows. printed board career Flux coating equipment Solder (molten state) solder tank Primary jet port propeller Secondary jet port propeller Second flux applicator Unfinished C No. figure No. 2/17 Ratsu 7 Zuda No. 1-Ll Figure 2

Claims (1)

[Claims] In a soldering method in which a board (1) that is automatically transported and electronic components mounted on the board (1) are soldered multiple times, flux is applied between each soldering. A soldering method characterized by: