JPH021596B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printed board soldering apparatus for integrated circuit elements (hereinafter referred to as IC).

[Prior Art] In recent years, ICs have improved in performance and become smaller, and high-density flat package ICs have now appeared in which the spacing between pins serving as external connection terminals is 0.6 mm. This kind of IC,
When mounting on a printed circuit board, conventional through-hole types require a metal pattern for soldering around the periphery of each pin hole, and there is a gap of 2.5 mm between the holes.
It cannot be used because it requires a space of more than mm.
Therefore, printed circuit boards for flat package ICs are non-porous, and are provided with a connection pattern consisting of parallel lines corresponding to a large number of pins that protrude radially and parallel to the board surface of the IC. There is only one.

In view of these circumstances, recently, the following IC printed board soldering apparatus has been put into practical use. In other words, a flat package IC is placed on a fixed printed circuit board using an accurate positioning device using a robot, and while the IC is being held, the
By irradiating the pins of an IC with electric heat, infrared rays, laser beams, etc., the connection pattern on the printed circuit board and the solder attached to the pins of the IC are temporarily melted and the two are connected (1984). September 24th “Nikkei Mechanical” Magazine No. 90
(See pages below).

[Problem that the invention seeks to solve]

According to the above-mentioned conventional example, a considerable investment is required for the positioning means and the heating means, and it is not suitable for widespread practical use. In addition, the heating method for melting solder relies on scanning in the direction in which the pins of the IC are aligned, which takes too much time and is disadvantageous for mass production.

[Means to solve the problem]

The present invention aims to solve the above-mentioned conventional drawbacks, and includes a structure that covers the upper part of the melted solder liquid tank.
A stand for IC mounting is arranged, and the top surface of this mounting stand is formed so that the IC can be positioned with the back side facing downward, and a window shaped along the direction of the IC pins is placed in the corresponding position. have and this
It is also equipped with means for positioning the printed circuit board so that each pin of the IC is applied to a predetermined printed pattern, and furthermore, a soldering iron is provided in the liquid tank so as to be able to come out and retract from the solder liquid level, and this iron The upper end surface is
A substantially rectangular horizontal plane is formed for each group of IC pins so that they all come into contact with the IC pins all at once through the window of the mounting table.

[Effect]

However, according to the present invention, simply by stacking the IC and the printed circuit board on the mounting means, the upper end surface of the soldering iron floating from the soldering bath comes into contact with all of the many pins of the correctly positioned IC at once. . In this way, when the soldering iron floats up, an appropriate amount of solder is scooped up and adheres to the pin part, and the heat of the solder soon reaches the connection pattern on the printed board via the pin, causing the solder to penetrate and lubricate between the two. At this point, however, by lowering the iron and waiting for the solder to cool, the IC pins can be attached to the printed board.

Separately, when a step is provided on the upper end surface of the soldering iron along the protruding end of the IC pin, tension is applied to the surface of the solder scooped onto the end surface due to tension force, which makes it possible to accurately measure the solder. , Smoothly cuts the solder when removing the iron from the pin.

〔Example〕

1 and 2 show an embodiment of the present invention, in which:
What is denoted by number 1 is a solder liquid tank. This liquid tank has a known heating means on the outside or inside thereof, and maintains the solder 11 dispensed inside in a molten state at a predetermined temperature, for example, 200°C. Preferably, the solder liquid level in the liquid tank should be kept constant by providing an overflow port, etc., and the solder surface should be kept clean by constantly flowing or by providing a scavenging means. .

2 is a iron that moves up and down in the liquid tank,
21 is its drive shaft, 22 is a drive means, and 23 is a soldering iron tip. Reference numeral 3 denotes a stand formed from a plate material by pressing or the like, and the IC 4 is mounted in a fixed position, for example, in a recess 31. Reference numeral 32 denotes a window bored to correspond to the pin 41 of the mounted IC, and its shape is likely to be approximately rectangular so as to cover at least a group of pins protruding from the side of the IC.
In this case, the number of windows is the same as the number of pin groups, and these windows are arranged so as to surround the IC mounting recess 31. Reference numeral 33 denotes a stud as an example of means for positioning the printed board 5. 6 is IC
4 and the printed board on the stand 3.

To explain the operation of the above embodiment device,
First, the IC 4 and printed board 5 are stacked and mounted in a predetermined direction on the stand 3 fixed horizontally above the solder tank 1, so that each pin of the IC corresponds to each connection pattern made on the printed board 5. is located. By crimping this with the pressing means 6, the IC and the printed board are firmly held.

Next, the iron 2 that was below the liquid level in the solder bath 1
When the iron tip 23 is floated by the driving means 22, an appropriate amount of melted solder is scooped onto the upper end surface of the soldering iron tip 23 according to the shape of the surface.

Furthermore, as the iron 2 is raised, the iron tip 23 is moved to the stand 3 as shown by the broken line in FIG.
through the window 32 and contact each pin of the IC 4 at the same time. Even at this time, the dimensions of each part of the iron 4 and the height of the stand 3 are determined so that the base of the iron 2 is immersed in the solder liquid in the tank 1. However, even when the soldering iron tip 23 is in contact with the pin 41 of the IC, the required temperature of the soldering iron tip is maintained, and the pin 41 and the connection pattern of the printed circuit board 5 through the pin are also moderately heated. By heating, the molten solder on the tip end surface of the soldering iron is infiltrated between the two using the capillary principle. Finally, by pulling down the iron at the right moment and waiting for the solder to cool, the IC installation on the printed circuit board is completed.

In the above embodiment, in addition to fixing the IC mounting stand 3 on the solder liquid tank 1, if the device of the present invention is to be incorporated into one process of the assembly line,
As shown in the figure, the table 3 may be made portable and transported between it and the conveyor line 7 by a known means 8, or the conveyor 7' installed above the solder tank 1 may be used intermittently as shown in Fig. 4. Measures such as running the patient may be taken as appropriate.

Figure 5 and subsequent figures illustrate various cross-sectional shapes of the soldering iron tip. Explaining this in sequence, Figures 5 to 6 show the shape determined by the amount of molten solder to be scooped onto the upper end surface of the iron tip, and Figures 8 to 10 show the shape determined by the amount of molten solder to be scooped onto the upper end surface of the soldering iron tip. This figure shows a shape when it is desired to give the transferred molten solder a flow phenomenon in a specific direction when the soldering iron tip is separated after transferring the molten solder. For example, in the one shown in Figure 9, a notch with a slight step on the upper end surface of the iron tip acts to pull the molten solder toward the extended end of the pin when it separates from the pin, and the solder is transferred to the IC.
It has the effect of preventing it from sagging toward the main body.

〔effect〕

According to the present invention described above, it is simple and economical because no special technology is required as a solder melting means and the conventional liquid bath type technology can be used, and all IC pins are bonded at the same time. Because of this, the work time can be significantly shortened, which is an unprecedented effect.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view of the present invention, Fig. 2 is a perspective view showing the correspondence of a part of Fig. 1, and Figs. 3 and 4 are planar configurations when the present invention is applied to assembly line work. Figures 5 to 10 show examples showing various shapes of the iron tip, which is a part of the main part of the present invention. 1... Solder liquid tank, 2... Soldering iron, 23... Soldering tip, 3... IC mounting stand, 31... Recess, 32...
...Window, 33...Stud, 4...IC, 41...
Pin, 5... Printed board, 6... Pressing means.

Claims (1)

[Scope of Claims] 1. A liquid tank for molten solder, a table arranged horizontally so as to cover the top of the liquid tank, and means for pressing and supporting IC components and printed boards sequentially loaded on the table in a fixed position; It consists of a soldering iron that can be freely extended and retracted from the solder liquid surface of the liquid tank, and the table has transparent parts for each set of pins at the positions corresponding to the pins when the IC is placed on the table. 1. A soldering device characterized in that a window is provided through which the tip of the soldering iron contacts each group of pins of the IC at the same time. 2. The soldering device according to claim 1, wherein the upper end surface of the soldering iron has a substantially longitudinal horizontal surface, and a notch forming a slight step is provided along one side of the upper end surface.