JPH0227976Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a flux management device for applying flux to an object to be soldered, such as a printed wiring board.

[Prior art and its problems]

The reason why flux is applied to the object to be soldered before soldering is to activate the object before soldering and to ensure good soldering.

If the flux does not have an accurate concentration value, good soldering cannot be ensured.

In particular, with the recent increase in the density of soldering, more precise flux concentration management is required.

Here, since the specific gravity of the flux is greatly affected by temperature changes, steady control of the temperature of the flux is also required.

Incidentally, flux is a mixture of a flux stock solution and a diluent (mainly alcohol).

However, most conventional flux management devices, like the flux management devices 1 and 1' shown in FIG. 2 or 3, simply detect the specific gravity of the flux 3 in the flux tank 2 using a specific gravity sensor 4. However, this specific gravity value signal is simply converted into a temperature-corrected specific gravity value based on the signal from the temperature sensor 5 similarly immersed in the flux 3, and it is not possible to obtain the flux 3 with an accurate concentration. Ta. 6 is a liquid level sensor, and 7 is a life sensor for flux 3.

The flux management devices 1, 1' shown in FIGS. 2 and 3 will be explained in more detail below.

First, the flux management device 1 shown in FIG. 2 will be explained.

In FIG. 2, 8 is a control circuit to which the outputs of the specific gravity sensor 4, temperature sensor 5, liquid level sensor 6, and upper and lower limit signals of the specific gravity of the flux 3 are input. Correct the input value to the specific gravity of a certain reference temperature, and compare the corrected specific gravity with the upper and lower limit set values, or adjust the liquid level within a predetermined range, that is, within the upper and lower limit values, using the input value from the liquid level sensor 6. At the same time, the signal from the life sensor 7
A display function is provided to display an output indicating whether or not the flux 3 should be replaced on a display section (not shown).

9 and 10 are electromagnetic valves, 11 is a pump, 12 is a stock solution tank containing a stock solution, 13 is a diluent tank containing a diluent, and 14 and 15 are supply pipes.

Note that the liquid level sensor 6 has three electrodes 6a, 6b, and 6c of different lengths, and the electrodes 6a, 6c,
Due to the conduction between 6b and 6c, above the flux 3,
Lower limit value is detected. Therefore, the control circuit 8 performs temperature correction of the specific gravity using the output values of the specific gravity sensor 4 and the temperature sensor 5, and compares the temperature-corrected specific gravity with the upper and lower limit set values, and if it is higher than the upper limit set value, the control circuit 8 The output of the circuit 8 operates the solenoid valve 10 and the pump 11 to supply the diluent in the diluent tank 13 to the flux tank 2, and if the flux is lower than the lower limit set value,
The output of the control circuit 8 operates the solenoid valve 9 and the pump 11 to supply the undiluted solution in the undiluted solution tank 12 to the flux tank 2 so that the specific gravity of the flux 3 falls within a predetermined range. It's in control.

When the flux 3 reaches the lower limit liquid level, the liquid level sensor 6 outputs the lower limit value, and the solenoid valve 9, pump 11, and solenoid valve 10 and pump 11 are operated alternately to pump the stock solution or diluent into the flux tank 2 until the flux 3 reaches the upper limit.
supply to.

In this way, the flux 3 under constant conditions is always supplied to the flux tank 2, and is applied to objects to be soldered, such as printed wiring boards, by a jet device (not shown).

Another conventional flux management device 1' will be described below with reference to FIG. Furthermore, the second
Explanation of parts common to the figures will be omitted.

27 is a temperature correction circuit, 28 is a differential amplifier, 16
1 is a digital panel meter, 17 is an upper and lower limit specific gravity setting device, 18 is an upper and lower limit specific gravity determination circuit, and 19 is a solenoid valve control circuit. A control circuit 8 is configured by these. 20 is a pressure air source, and 21 and 22 are pressure air supply pipes.

Therefore, during automatic operation, the changeover switch 23 is set to the automatic side as shown in FIG. By doing so, the temperature sensor 5 outputs an output according to the temperature, and a part of this output is sent to the temperature correction circuit 27.
For example, based on the temperature of this circuit 27,
With 20℃ as the standard, if it is 20℃ or higher, it is corrected to output a positive output of the difference required for temperature correction, and the output corresponding to this output and the specific gravity of the specific gravity sensor 4 is adjusted to 20℃.
It is input to the differential amplifier 28 so as to convert it into .

The output of the differential amplifier 28 is compared with the upper and lower limit setting values of the upper and lower limit specific gravity setter 17 in the upper and lower limit specific gravity determination circuit 18 in terms of specific gravity values.

When the value of specific gravity is high or low, an output is output from the upper and lower limit specific gravity determination circuit 18 to the solenoid valve control circuit 19, which controls the solenoid valve 9 or 10 to supply pressure air from the pressure air source 20 to the pressure air supply pipe 21, 22, and the pressurized air A is supplied to the stock solution tank 12 containing the flux source solution 24 or the diluent solution tank 13 containing the dilution solution 25.

Therefore, the stock solution tank 12 or diluted solution tank 13 is removed by an amount proportional to the time that the solenoid valve 9 or 10 is open.
The stock solution 24 or diluted solution 25 is added to the flux tank 2.
is supplied to maintain the specific gravity of flux 3 within a predetermined range.

Incidentally, when the liquid level sensor 6 outputs the upper limit liquid level of the flux 3, the solenoid valve 9 or 10 is immediately closed.

Further, the lower limit liquid level of the flux 3 is detected by the liquid level sensor 6, and the stock solution 24 or the diluted solution 25 is supplied to the flux tank 2 while keeping the specific gravity within a predetermined range until the lower limit value is output.

The above conventional flux management devices 1, 1' are as follows:
A certain degree of specific gravity of flux 3 can be maintained at all times.

However, as explained above, the conventional flux management devices 1 and 1' only correct the measured specific gravity signal of the flux to a predetermined temperature value, and in reality, the flux 3 to be used is adjusted to a predetermined temperature value. Since the temperature has not been changed, it is not possible to obtain flux 3 with an accurate concentration.

Therefore, the conventional flux management devices 1 and 1' have the disadvantage that highly accurate soldering cannot be performed.

That is, although it is well known that the temperature of the flux 3 has a large effect on the defect rate, which indicates the percentage of soldering quality, conventional flux management devices 1 and 1' do not maintain the constant temperature of the flux 3. Currently, little consideration is given to control measures.

Incidentally, in the flux management devices 1 and 1' shown in FIGS. 2 and 3, although not shown, like the flux management device 1'' shown in FIG. 3 to foam tube 2
9 to form a foam, guide it upward through a foam cylinder cover 30, flatten it through a foam nozzle 31, and apply the flux to an object to be soldered such as a printed wiring board to be soldered. It is equipped with

In order to eliminate the drawbacks of the conventional flux control devices 1 and 1' mentioned above, there is a device that uses constant temperature control for fluxes, as disclosed in Japanese Patent Laid-Open No. 53-72755.
There is something that can be seen in the issue.

This flux management device 1'' will be explained below using FIG. 4.

This flux management device 1'' includes a temperature sensor 5 such as a thermocouple or thermistor placed in a flux tank 2, and a signal from this temperature sensor 5 is applied to a temperature control device 32, which outputs a set temperature value signal from a temperature setting device 33. The flux 3 in the flux tank 2 is compared with the signal from the temperature sensor 5, and a heat exchange device 34 such as a heater and a cooler installed outside the flux tank 2 is driven to heat or cool the flux tank 2 to cool down the flux 3 in the flux tank 2. The flux 3 is maintained at a predetermined temperature by raising or lowering the temperature.

This flux management device 1'' has flux 3
It is certainly useful because it keeps its temperature constant.

However, since this flux management device 1'' is equipped with a heater such as a heater and a heat exchanger such as a cooler at the bottom of the flux tank 2, it is extremely dangerous and requires monitoring during use. As an automatic device, I was urged to take a step closer to considering it.

The reason why this flux management device 1″ is dangerous is as follows.
This is due to the properties of the flux 3 in the flux tank 2.

That is, since the flux 3 contains alcohol, there is a risk of explosion if the flux 3 is heated or by heat generated from a heater or a cooler.

In addition, when the alcohol in flux 3 evaporates due to heating or heat generated from a heater or cooler, the specific gravity of flux 3 containing alcohol changes significantly, making it difficult to know the exact concentration of flux 3. There are drawbacks that go away.

In addition, since a cooler and a heater are attached to the flux tank 2, the flux tank 2, which is already large, becomes very large.There is no flexibility in arranging the flux tank 2 itself, and the installation structure for the automatic soldering device becomes extremely complicated. However, it had drawbacks that severely restricted its use.

Another known flux management device that performs constant temperature control measures is to insert a bellows tube into the flux tank 2, send cold air from a cooler to the bellows tube, and connect it to a heater. There is a device in which a bellows tube is inserted into the flux tank 2, and hot air from a heater is sent to the bellows tube to control the constant temperature of the flux 3 in the flux tank 2.

This method is safer than the flux management device 1'', but if the bellows pipe becomes old and becomes damaged or has holes, the hot air will come into direct contact with the flux 3 containing alcohol, so the flux will still be damaged. There is a risk of ignition and explosion.

Further, the flux tank 2 such as the ordinary flux management device 1, 1', 1'' has a storage capacity of 5 to 101 [liters] of flux 3, and is also equipped with the jet device described above. Therefore, in order to insert two bellows tubes, one for cooling and one for heating, into the flux tank 2, the flux tank 2 must be made even larger. had the disadvantage of limiting its use.

[Problem for invention]

The present invention allows the flux tank and constant temperature control device to be installed separately, so the flux tank does not need to be large-sized, and the mounting structure for automatic soldering equipment can be flexible. In addition, even if a constant temperature control device is used, there is no danger of flux containing alcohol igniting and exploding, and furthermore, by not directly heating the flux in the flux tank, the alcohol in the flux can be reduced. The objective was to prevent the flux from evaporating and to be able to determine the exact concentration of the flux.

[Means for achieving the task of the present invention]

The problems of the present invention are to provide a flux tank for storing flux consisting of a diluent and a flux undiluted solution, a means for detecting the temperature of the flux in the flux tank, a constant temperature tank containing a liquid, and a liquid immersed in the liquid in the constant temperature tank. a flux suction/delivery means for circulating the flux in the flux tank between the flux tank and the constant temperature tank via the heat exchange pipe, a controller for driving the suction/send of the flux suction/send means; To provide a flux management device comprising a means for cooling and heating a liquid to cool and heat a flux in a heat exchange pipe immersed in a constant temperature bath, and a controller for controlling the cooling and heating means. It can be achieved.

[Embodiment of the invention] Hereinafter, a flux management device 1'' as an embodiment of the invention will be described with reference to FIG.

A flux 3 is placed in the flux tank 2. The method of supplying the flux stock solution and diluted solution into the flux tank 2 until the specific gravity of the flux 3 reaches a predetermined value has already been explained in connection with the flux management devices 1 and 1' in FIGS. 2 and 3. However, since it is sufficient to adopt these methods in the present invention, their explanations will be omitted in this embodiment.

Further, inside the flux tank 2, a liquid level sensor 6, a specific gravity sensor 4, and a life sensor 7 (not shown) are installed. Various operations are performed in accordance with signals from these sensors and the same control circuit 8 as described above. Since these operations have already been explained with respect to the flux management devices 1 and 1' shown in FIGS. 2 and 3, their explanation will be omitted.

A foaming cylinder 29 is provided at the bottom of the flux tank 2, and a foaming nozzle 31 is provided at the top thereof to guide air bubbles 35 generated from the foaming cylinder 29 to the upper part and form a flat guiding jet.

A temperature sensor 5 such as a thermocouple or a thermistor is inserted into the flux 3 of the flux tank 2.

Further, one end of the suction pipe 36 and the other end of a heat exchange pipe 37 made of a flexible metal body made of a material with good thermal conductivity, such as stainless steel, are inserted into the flux 3 of the flux tank 2.

38 is a constant temperature control device for the flux 3. The temperature value signal of the flux 3 detected by the temperature sensor 5 is output to the controller 39 of the constant temperature control device 38 . .

In the following, the constant temperature control device 38 will be mainly explained.

40 is a constant temperature bath filled with a non-volatile liquid such as water, for example water 41. Water 41 is in a constant temperature tank 40
In order to prevent overflow from the temperature chamber 40,
An over-rise prevention sensor 42 is attached to. The output from this over-rise prevention sensor 42 is transmitted to the controller 3.
9, and an output signal from the controller 39 controls a supply means (not shown) for water 41, so that the level of water 41 in the constant temperature tank 40 is always kept constant. Further, the constant temperature tank 40 is provided with a safety mechanism (not shown) for discharging the excessively heated water 41 to the outside.

The controller 39 is powered by an AC power source (e.g.
100V)) Convert the AC signal from 43 to AC~
It is designed to be driven by DC power from a power supply device that converts it to DC power.

One end of the supply pipe 37 is inserted into the flux 3 of the flux tank 2, and the other end of the supply pipe 37 is connected to the circulation pump 4.
Connected to 4. One end of the heat exchange pipe 37 is connected to the circulation pump 44, the middle part of which is immersed in water 41 in the constant temperature tank 40, and the other end of the heat exchange pipe 37 is inserted into the flux 3 as described above. has been done.

Therefore, the temperature value signal of the flux 3 in the flux tank 2 is sent to the controller 3 via the temperature sensor 5.
9 and is compared with the set temperature (usually 20°C is selected, but other temperatures may be selected), and if it is lower than the set temperature,
When the water is heated by the heater 48 immersed in the water 41 in response to a control signal from the controller 39, the heat exchange pipe 37 immersed in the water 41 is heated (warmed). 3 can also be heated. Therefore, the flux 3 in the flux tank 2 is circulated by the circulation pump 44 via the supply pipe 36, the circulation pump 44, and the heat exchange pipe 37, and is returned to the flux 2 in the flux tank 2.
Since the flux 3 passing through the heat exchange pipe 37 immersed in the heated water 41 is warmed by the warmed water 41, the flux 3 in the flux tank 2
is maintained at a predetermined temperature by the controller 31 based on the temperature value signal from the temperature sensor 5.

In this way, the circulation pump 44 is connected to the supply pipe 3
6, the flux 3 in the flux tank 2 is sucked by the circulation pump 44, and the sucked flux 3 is transferred to the heat exchange pipe 3 by the circulation pump 44.
By circulating the flux 3 in the flux tank 2 through the flux tank 7, the flux 3 in the flux tank 2 is maintained at a set temperature.

Reference numeral 45 denotes a shaker for water 41 which is immersed in a constant temperature bath 40 and rotated by a motor 46, the rotational speed of which is adjusted and set by a signal from a controller 39. ing.

47 is a float switch whose predetermined portion is immersed in the water 41 of the constant temperature tank 40. A signal from this float switch 47 is output to the controller 39, and if the water 41 in the constant temperature tank 40 rises above a predetermined level, If there is, an alarm signal is generated together with the over-rise prevention sensor 42, and a means for keeping the level of the water 41 in the constant temperature tank 40 constant is activated.

49 is a refrigerator, and the cooling part is connected to water 41 in a constant temperature tank 40.
The cooling pipe 50 immersed in the flux 3 is cooled under control by a signal from the controller 39 (at this time, it is controlled based on the temperature value signal of the flux 3 from the temperature sensor 5). is below the set temperature, the cooler 49
operates, cools the cooling pipe 50, and cools the constant temperature bath 4.
Cool the water 41 in 0. While the refrigerator 49 is operating, the heating of the heater 48 is stopped by a signal from the controller 39.

Note that when the flux 3 in the flux tank 2 reaches a predetermined temperature value, the controller 39 turns on the heater 48.
Alternatively, the operation of the refrigerator 49 is stopped. However, even in such a case, it is desirable to keep the circulation pump 44 in operation at all times.

[Effect of idea]

As is clear from the above, the flux management device 1'' of the present invention has a flux tank 2 and a flux 3.
Since the constant temperature control device 38 is formed separately, the flux tank 2 does not have to be made large, and it is possible to have a degree of freedom when installing it to an automatic soldering device, so it can be used in various ways. You can choose the placement method. Furthermore, since the constant temperature control device 38 for the flux tank 2 and the flux 3 is formed separately, the flux 3 in the flux tank 2 is not directly heated, so there is a risk that the flux 3 containing alcohol may catch fire and explode. There is no sex.

Furthermore, even if the heat exchange pipe 37 is damaged and has a hole, the flux 3 will flow into the water 41 in the constant temperature tank 40, so the flux 3 will be diluted.
Even when heated by the heater 41, there is no risk of ignition and explosion.

Furthermore, the flux 3 in the flux tank 2 is constantly circulated by the circulation pump 44, and the temperature of the flux 3 itself is always maintained at a set temperature, so that the flux 3 can be adjusted to an accurate concentration (specific gravity). This has the effect of enabling highly accurate soldering.

Furthermore, since the alcohol in flux 3 is prevented from evaporating when the flux is heated, accurate concentration control of the flux is extremely easy.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a flux management device of the present invention, and FIGS. 2 to 4 are explanatory diagrams of conventional flux management devices. 1, 1', 1'', 1...flux management device,
2...flux tank, 3...flux, 4...
Specific gravity sensor, 5... Temperature sensor, 6... Liquid level sensor, 6a, 6b, 6c... Electrode, 7... Life sensor, 8... Control circuit, 9, 10... Solenoid valve, 1
1... Pump, 12... Stock solution tank, 13... Diluted liquid tank, 14, 15... Supply pipe, 16... Digital panel meter, 17... Upper and lower limit specific gravity setting device,
18... Upper and lower limit specific gravity determination circuit, 19... Solenoid valve control circuit, 20... Pressure air source, 21, 22...
... Pressure air supply pipe, 23 ... Selector switch, 24 ... Flux stock solution, 25 ... Diluted liquid,
26... Air source, 27... Temperature correction circuit, 28...
... Differential amplifier circuit, 29 ... Foam tube, 30 ... Foam tube cover, 31 ... Foaming nozzle, 32 ... Temperature control device, 33 ... Temperature setting device, 34 ... Heat exchange device, 35 ... Air bubbles, 36... suction pipe, 3
7... Heat exchange pipe, 38... Constant temperature control device, 39... Controller, 40... Constant temperature tank, 4
1...Water, 42...Overheat prevention sensor, 43...
AC power supply, 44...Circulation pump, 45...Humper, 46...Motor, 47...Float switch, 48...Heater, 49...Freezer, 50...
cooling pipe.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A flux tank for storing a flux consisting of a diluent and a flux stock solution, a means for detecting the temperature of the flux in the flux tank, a constant temperature tank containing a liquid, and the above constant temperature tank. a flux suction/delivery means that circulates the flux in the flux tank between the flux tank and the constant temperature tank via a heat exchange pipe immersed in a liquid therein; a controller that drives the flux suction/delivery means to suck and deliver; A flux management device comprising means for cooling and heating the liquid in the constant temperature bath to cool and heat the flux in the heat exchange pipe immersed in the constant temperature bath, and a controller for controlling the cooling and heating means. . (2) The flux management device according to claim 1, wherein the flux tank includes a foam tube and a foam nozzle for jetting flux. (3) The flux suction/delivery means for circulating the flux in the flux tank between the flux tank and the constant temperature tank via a heat exchange pipe immersed in the liquid in the constant temperature tank includes a circulation pump and one end connected to the flux tank. A suction pipe is inserted into the flux in the flux tank, and the other end is connected to the circulation pump.One end is connected to the circulation pump, the middle part is immersed in the liquid in the constant temperature tank, and the other end is connected to the flux in the flux tank. 2. A flux management device according to claim 1 or 2 of the utility model registration, comprising a heat exchange pipe inserted into a heat exchange pipe and a controller for driving suction and delivery of a circulation pump. (4) The means for heating and cooling the liquid in the constant temperature bath is a heater that is immersed in the constant temperature bath and heated by a controller, and a refrigerator whose operation is controlled by the controller. A flux management device according to any one of claims (1) to (3) of the utility model registration claim, which comprises a cooling pipe. (5) The above-mentioned constant temperature bath is provided with a means for extracting the liquid inside the bath, as claimed in claim (1) of the utility model registration.
The flux management device according to any one of items (4) to (4). (6) The above-mentioned constant temperature bath is provided with means for preventing excessive rise in liquid, as set forth in claims (1) to (5) of the utility model registration claims.
The flux management device according to any one of the above. (7) The flux management device according to any one of claims (1) to (6), wherein the liquid in the constant temperature bath is a non-volatile liquid.