JPS62199266A - Soldering device for electric substrate - Google Patents

Abstract

PURPOSE:To stick a solder surely and uniformly at all times to a substrate by keeping the jet stream height within the necessary range always by transmitting a signal showing that the liquid level height of a molten solder becomes out of the necessary range, at that time. CONSTITUTION:The liquid level is ascended upto the necessary liquid level height with a solder being fed into a tank 1 from a feeding device as well as with ringing of a buzzer by transmitting a signal from a sensor 23 in case of the space between the sensor 23 and float 19 being not within the necessary interval, when a soldering device is driven. On the other hand the sensor 23 is not actuated in case of within the necessary interval at the driving start time. The quantity of molten solders is gradually reduced when the soldering is performed with the substrate being fed continuously in the state of the liquid level height being within the necessary range and a jet stream height (a) and (h) being in the necessary range. Namely the liquid level height is lowered and the gap between the sensor 23 and float 19 is spreaded. The sensor 23 transmits a signal thereupon, the solder is fed into the tank 1, the jet stream height (a) and (h) is always made within the necessary range and good soldering is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus that generates a jet of molten solder in a tank, and brings the back surface of a board on which electrical components are mounted into contact with the jet to adhere the solder.

[Conventional technology and its problems]

A flow solder machine is usually used as a device to insert the wire terminal of the electrical component from the surface of the board, stick solder to the T9 terminal that protrudes from the backside, connect the terminal to the printed wiring on the backside of the board, and attach the electrical component to the board. is used. This causes a jet to form in the molten solder 2 in the tank 1, as shown in FIG. 1, and as shown in FIG.
This is a device for attaching solder by bringing the back surface of the board 4 into contact with the solder.

During this soldering process, the problem is how to adhere the solder to the board 4 reliably and uniformly, but most of the quality depends on the width t of the jet solder that coats the board 4 (see Fig. 5). ) and the density of the solder jet.

The above-mentioned width is determined by the relationship between the height H at which the substrate 4 is continuously fed and the height h of the jet stream 3. On the other hand, assuming that the density of the molten solder 2 is constant, the density of the solder jet is determined by the height a of the jet rising from the liquid surface, and the higher the density, the smaller the jet and the lower the higher. This jet height a is influenced by the amount of molten solder when the jetting force is constant; when the jetting force is large, the jetting height is high, and when the jetting force is small, the jetting height is lower.

Therefore, in this type of soldering, the action is the height of both jets,
It is desirable to set a to an optimal value.

However, in the past, the jet height h was measured visually at intervals during continuous board feeding, and the tank 1 was raised and lowered manually to obtain the required width t1, for example, 20 to 40 cm. . That is, the height 3 of one of the jets is not considered.

If the jet height 3 is not taken into account, the density will not be within the required range even if the width is within the required range, and not only will the best solder adhesion not be achieved, but also the jet height a, depending on the amount of molten solder. Since the degree of decrease in h also differs, when the amount decreases, the jet height h will decrease significantly by the time of the next measurement, and the width t will often go out of the required range.

The present invention takes the above points into consideration and aims to reduce the jet heights a and h within a required range.

[Means for solving problems]

In order to achieve the object of item 1, a float is provided on the liquid level in this invention, and above the float,
A float detection sensor supported by a tank is provided, and the sensor generates a signal when the distance between the sensor and the float is greater than a predetermined distance.

[Effect]

With this configuration, the amount of molten solder so that the jet height a falls within a predetermined range, that is, the gap width between the sensor and the float, is determined, and the solder is poured into the tank so that the predetermined gap is achieved.

In this state, as soldering work is performed, the amount of solder gradually decreases. Along with this, the float also descends,
When the float separates from the sensor by more than the required distance, the sensor detects this and issues a signal.

Based on this signal, an alarm is issued to notify the operator that the amount of solder has decreased beyond the allowable limit, and the solder supply device is driven to replenish the tank with solder.

In this way, the jet heights a and h are always maintained within the required range, and good soldering to the board is achieved.

〔Example〕

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

As shown in FIG. 1, a guide shaft 1 is mounted on a base 10.
1, a tank 1 is supported so as to be movable up and down. Also,
A screw shaft 12 from the base 10 is brought into contact with the bottom surface of the tank 1, and by turning this shaft 12, the tank 1 can be raised and lowered.

The tank 1 is provided with a support rod 13 that protrudes laterally, and a contact point 16 of a dial gauge 15 supported by the base 10 via an arm 14 comes into contact with the support rod 13. Measure the amount of elevation of tank 1.

The tank 1 is filled with solder, which can be melted by various means, such as electric heating. The molten solder is stirred by a fan 17 and made uniform.

A frame 18 is provided at a position separated from this fan 17, and air is sent into the lower part of this frame 18 to generate a jet stream 3.

A float 19 is floated on the static liquid surface which is not affected by the jet flow 3. This float 19 has a cylindrical shape with a lid, and its surface is coated with tetrafluoride resin to prevent solder from adhering to it, and a deaeration hole 20 is formed in the lid, so that the float 19 can be accurately adjusted to the liquid level. It is designed to rise and fall according to the

Furthermore, an arm 2 extending upward from the tank 1 to the float 1'9
1 is provided, and a guide pin 22 extends downward from this arm 21 so that the float 19 is raised and lowered at that position. Further, a sensor 23 is provided on the surface of the arm 21 facing the float 19. This sensor 23 is connected to a detection plate 24 made of a stainless steel plate on the top surface of the float 19.
is detected, and when the distance between the two reaches a state where the required range of the jet height 3 cannot be obtained, a signal is issued to the detection controller 25.

The controller 25 can set the required range of the distance between the sensor 23 and the float 19, that is, the lower limit of the molten solder level, and is connected to the main controller 26 to control the jet flow. When you turn on the operation switch, it starts working.

''-The controller 25 is equipped with a buzzer 27 and solder is supplied into the tank 1 by the supply device 28 when the solder is automatically supplied or less, and when the upper limit signal is received, the supply is stopped.

Next, the operation of the embodiment will be explained.

First, as described above, the width of the jet solder coated on the substrate 4 needs to be in a range of, for example, 20 to 4 Q mm. At this time, the required jet solder density (jet height a)
The relationship between the height of the tank 1 from the reference plane and the height of the molten solder and the depth inside the tank, which can obtain widths of 20 mm, 3 Q mm, and 4 Q mm, is, for example, the graph shown in Figure 3. . Therefore, in order to obtain good solder adhesion, it is necessary to set the liquid level height and the height of the tank 1 within the range shown by diagonal lines. Note that the reference plane for the height of the tank 1 is determined as appropriate.

Therefore, the tank 1 is set at an appropriate height, for example, 1. □ The controller 5 sets the required distance between the sensor 23 and the float 19, that is, the upper and lower limits of the distance, so that the liquid level height corresponding to the height is 71.5 mm to 75 mm. Set to .

When the soldering device is operated with the above settings, if the distance between the sensor 23 and the float 19 is not within the required distance, the sensor 23 will issue a signal, the buzzer 27 will sound, and the supply device 28 will send the tank 1 Solder is fed into the tank, and the liquid level rises to the upper limit of the required liquid level height, for example, 75 mm.

On the other hand, if it is within the required interval at the start of driving, the sensor 23
doesn't work.

In this way, when the board 4 is continuously fed and soldered while the liquid level height is within the required range and the jet heights a and h are within the required range, the amount of molten solder gradually decreases. . That is, the liquid level height decreases and the distance between the sensor 23 and the float 19 increases. When this interval exceeds the required range, that is, when the liquid level exceeds the lower limit, the sensor 23 issues a signal and solder is supplied to the tank 1 by the same action as described above.

As shown in (2) below, the jet heights a and h are always kept within the specified range to ensure good soldering.

In addition, in the embodiment, when automatically supplying solder, it is not necessary to provide the buzzer 27, and the buzzer 2
Solder may also be added manually based on the call in step 7.

〔effect〕

According to this invention, when the liquid level of the molten solder is out of the required range, a signal indicating this is emitted, and this signal can be used to automatically supply solder into the tank or to issue an alarm. , it is possible to notify the operator of this fact, and therefore it is possible to always maintain the jet heights a and 11 within the required range, which has the effect of ensuring that solder always adheres to the board reliably and uniformly. .

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of one embodiment of the device of the present invention, and FIG.
1 is a control block diagram of FIG. 1, FIG. 3 is a diagram showing the relationship between the tank height and the liquid level, and FIGS. 4 and 5 are diagrams explaining the operation of soldering the circuit board. 1... Tank, 2... Molten solder, 3... Jet stream, 4
... Board, 19... Float, 21... Arm, 23
···sensor.

Claims (3)

[Claims] (1) Stir the molten solder in the tank to create a jet,
In a soldering device that attaches solder by bringing the back side of a board on which electrical components are mounted into contact with the jet stream, a float is provided on the surface of the molten solder, and a float detection sensor supported by a tank is installed above the float. established,
An electrical board soldering device characterized in that the sensor generates a signal when the distance between the sensor and the float is greater than a predetermined distance. (2) The electrical board soldering apparatus according to claim (1), characterized in that a tetrafluoride resin layer is provided on the surface of the float. (3) The electrical board soldering apparatus according to claim (1) or (2), wherein the tank is supported so as to be movable up and down.