SU1172663A1 - Arrangement for applying the flux - Google Patents

Abstract

The FLUSH APPLICATION DEVICE is mainly a foam wave method, which contains a flux solution bath installed in the housing, in which the slotted nozzle 17 with brushes is located, and mounted inside the slotted nozzle and. A foaming element connected to the air line, characterized in that, in order to improve the quality of flux application and reliability by maintaining a constant height of the flux column above the foaming element, the device is equipped with elastic elements installed by the 1Ud bath at the bottom of the body, bath position sensors mounted inside mounted on the bath with the ability to interact with the sensors, while the slotted nozzle is rigidly fixed to the housing. M 1CHE O5 O5 co

Description

111

The invention relates to automated equipment for group soldering, in particular to ancillary equipment for the deposition of flux, mainly by the wave method, and can be used in various industries under continuous and mgcss production.

The purpose of the invention is to improve the quality of flux deposition and the reliability of the device,

Fig. 1 shows a flux deposition device; in fig. 2 - device for automatic control and support of flux level,

In the device case 1, a bath 2 with a solution of the flux 3 is installed with the possibility of vertical movement (FIG. 1). The slotted nozzle 4, provided with brushes 5 and 6, is located in the bath 2 with the flux solution 3 and is rigidly connected to the housing 1. Inside the nozzle A, a foaming element 7 is mounted, the core 8 of which is connected to the air line (not shown To Bath 2 in housing 1 mounted on spring elements 9 and 10. Sensors II and 12 of bath 2 are mounted inside housing 1, and the grids 13 and 14 are not on bath 2. Printed circuit 15, on the bottom surface of which flux is to be applied, is in contact with brushes 5 and 6, Stop, 16, mounted on housing 1, serves as The restriction of the movement of the bath 2 downward, and the stop 17, also mounted on the housing 1, serves to limit the movement of the bath 2 upwards under the action of the springs 9 and 10 of the springlift.

Sensor 11 (, 12j position of bath 2 can be made, for example, in the form of a limit switch micro switch (Fig. 1). The opening contact 18 of the sensor 11 of the lower position of the bath 2 is connected in series with the closing contact 19 of the sensor 12 of the upper position of the bath 2 to the power supply circuit. the coil 20 of the contactor (starter (Fig. 2). The latter serves to automatically connect the voltage supply network or to the pump for pumping the flux solution to the bath 2 from the reservoir (the latter are not shown). Closing contact 21 of the contactor and closing contact 22 of the button

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The start-up is connected parallel to the closing contact 19 of the sensor 12 of the upper position of the bath 2. The start button is located on the front panel of the control unit of the device (the J,

On the front panel of the control panel of the device, there are also indicator lights for the Flux volume,

 testify; ie: light bulb 23 Baim. - on the smallest permissible volume of the flux solution 3 in bath 2. In the power supply circuit of the bulb 23 Naim, the closing contact 26 of the sensor 12 of the upper bath position is turned on. In the power supply circuit of the bulb 25 Naib. The closing contact 27 of the sensor 11 of the lower position of the bath 2 is switched on. In the power supply circuit of the lamp 24 Norm.

in series, the opening contacts 28 and 29 of sensors 11 and 12 of lower and upper positions 2, respectively, are included.

The flux deposition device works as follows.

Due to the fact that the solution of the flux 3 is a relatively rapidly evaporating and solidifying liquid, it must be drained from the bath 2 into the tank at the end of the work shift (drain pipe and tank not shown). To fill the bath with 2 flux solution 3, it is necessary to press the Start button on the front panel of the device control panel. In this case, the closing contact 22 of the Start button connects the supply voltage to the coil 20 of the contactor along the circuit: plus the source

power, disconnecting contact 18 of sensor 11, closed contact 22 of the Start button, contactor coil 20 minus the power supply. Contactor sgateat, closing it

Pin 21 bypasses the closing contact 22 of the Start button. In addition, the closing contacts of the contactor, not shown in the drawing, connect the supply voltage to the pump

or solenoid valve (in

depending on the specific design of the make-up device with a flux solution). At the same time, the flux solution is either pumped from the reservoir to the bath 2 by means of a pump that is turned on, or flows from the reservoir to the bath 2 through an open solenoid valve. As the flux 3 solution enters the bath 2 from the tank, the load acting on the springs 9 and 10 of the spring-loaded nickname increases. Under the action of age-load, the latter are compressed, causing the bath 2 to move downwards. When completely filled with the flux 3 solution of bath 2, the latter occupies the extreme lower position. In this case, the pusher 13 acts on the drive element of the sensor 11 of the lower position of the bath 2. The sensor 11 is activated and its disconnecting contact 18 opens the supply circuit of the coil 20 of the contactor. The latter returns to its original state and opens the supply circuit of the pump (or solenoid valve) with its closing contacts. The flow of the flux solution 3 into the bath 2 is stopped. In addition, the closing contact 27 of the sensor I1 of the lower position of the bath 2 closes the circuit of the 25 indicator light bulb (Fig .2 J. The luminescence of the latter on the front panel of the device control panel indicates that the flux 3 solution in bath 2 is in full (the maximum allowable volume. The flux application device is prepared for operation. When feeding black Without a cavity 8 of a foaming element 7 of compressed air, the flux solution 3 inside the slotted nozzle 4 over the foaming element 7 made of porous ceramic foams from the main line foaming with air coming out of the pores of the foaming element 7. above and in the form of foamy ceramic nozzles 4. The amount of foam produced is regulated by changing the pressure (flow rate) of compressed air supplied to the cavity 8 of the foaming element 7 from two opposite sides. Vertical brushes 5 and 6 are used to maintain a uniform level of the surface of the foam above the outlet of the slot nozzle 4 and to evenly distribute the flux on the bottom surface of the circuit board. The uniformity of the dimensions of the porous material from which the sweeping element 7. 634 The flux is applied by a foam wave by contacting the bottom surface of the circuit board 15, which is translational , with a crest of foam wave, as a result of which the flux bubbles are destroyed and the soldering places are covered with a thin layer of flux composition. As the flux is transferred to the surface of the circuit boards 15, the volume of the solution of the flux 3 in the bath 2 decreases. The load acting on the springs 9 and 10 of the spring lift is also reduced. As a result, the bath 2 is raised, and the level of the flux solution 3 in the bath and in the slit nozzle 4 above the foaming element 7 remains constant. By this, the height of the combed-wave wave is achieved in the device, and therefore, the thickness of the applied flux layer on the surface of the board does not change during operation of the device, i.e. The quality of the flux applied to the circuit boards is increased. The bath 2 in the operating state of the device is in an intermediate position. In this case, none of the limiters 13 and 14 is in contact with the sensors 11 and 12. The latter are in the initial state and, with their opening contacts 28 and 29, close the power supply circuit of the signal lamp 24 Norm. (figure 2). The glow of the latter on the front panel of the device control panel indicates that there is a solution of the flux 3 in the bath 2 in the normal (working) volume. When the flux solution 3 in the bath 2 reaches the smallest permissible volume, bath 2 occupies the uppermost position. In this case, the pusher 14 acts on the drive element of the sensor 12 of the upper position of the bath 2. The sensor 12 is triggered and connects the supply voltage to the contactor coil 20 via the contacting terminal 19: plus the power supply, disconnecting contact 18 of the sensor 11, closed contact 19 of the sensor 12, contactor coil 20, minus power supply. The contactor operates, its closing contact 21 bypasses the closing contact 19 of the sensor 12. In addition, the closing contacts of the contactor connect the supply voltage

or pump or solenoid valve, i.e. the bath 2 is filled with a solution of the flux 3 until the sensor 1I triggers the lower position of the bath 2, as already described.

At the same time, when the sensor 12 of the upper position of the bath 2 is triggered, the power supply of the signal lamp 24 Nom. by means of the opening contact 29 of the sensor 12, and by means of the closing contact 26 of the sensor 12, the power supply of the signal lamp 23 is closed. (Fig. 2 J.. The glow of the last in front of her panel of the control panel. device indicates the presence of a solution of flux 3 in bath 2 in the smallest allowable volume.

The presence of the sensor) 1 automatic control of the lower position of the bath 2 with the flux solution 3 eliminates the possibility of flux getting to the upper side of the printed circuit board 15, since the possibility of overflow of the flux solution 3 into the bath 2 is more acceptable, and the presence of the sensor 12 of the automatic control of the upper bath 2 with. the flux solution 3 eliminates the possibility of non-wetting with the flux of the bottom side of the printed circuit board 15, since the possibility of a flux solution 3 consumption being excluded is excluded. This achieves a more reliable operation of the device for applying a flux.

The sensors 11 and 12 of the automatic control of the position of the bath 2 with the solution of the fluid 3 are mounted inside the housing 1 of the device. Contact with corrosive medium - flux solution 3 and its is completely excluded. in pairs. This increases the reliability of the operation of the sensors 11 and 12 and, consequently, increases the reliability of the operation of the entire device for applying a flux.

To ensure a constant level of the flux i3 solution in bath 2 and in the internal cavity of the slotted nozzle. 4 above the foaming element 7 during the operation of the device, the following condition is necessary. The total stiffness of the springs 9 and 10 of the spring lift should be proportional to the mass of the flux solution column 3 of unit height i

Z.

rs,

- stiffness of the i-th spring,

Z.

kg / cm; n is the number of springs of the lift;

V is the density of the flux solution, kg / cm;

S is the bath area occupied by the flux solution, see

Claims (1)

DEVICE FOR APPLICATION OF FLUX mainly by the foam wave method, comprising a bath with a flux solution installed in the housing, in which a slot nozzle with brushes is located, and a foaming element mounted inside the slot nozzle and connected to the air duct, characterized in that, in order to increase the quality of the application of flux and reliability by maintaining a constant height of the column of flux above the foaming element, the device is equipped with elastic elements installed under the bath at the bottom of the body, polo sensors eniya tub mounted inside fixed on the bathtub to interact with sensors, wherein the slotted nozzle is rigidly fixed to the housing. SU, „, 1172663 Figure 1