SU1291319A2 - Device for applying flux - Google Patents

Abstract

The device belongs to the soldering area. The aim of the invention is to improve the reliability of the device. A slotted nozzle, provided at the outlet with brushes, is located in the bath (B) and is rigidly connected to the housing. The blowing element (VE) is mounted inside the nozzle and connected to the air line. An additional brush to remove excess flux is installed at the outlet of the device. Closed on top of the net to accelerate the conversion of foam to liquid. The bottom and top position sensors B are mounted inside the case, and the stops are mounted on a pallet. A portion of the turns of the elastic member is screwed at one end into a nut that rotates in the body plate. A pipe rigidly connected to its second end is installed inside the elastic element. The rod is screwed into the threaded hole of the pipe and, through a spherical support mounted in the pan, contacts B. The device provides a constant height of the foam wave, automatically maintaining a constant level of the flux solution in В and in the slit nozzle above the RE. Additional to auth. W St. № 1172663. 2 z. P. f-ly, 3 ill. (L TOS with with with Go

Description

The invention relates to the field of soldering, in particular to ancillary equipment for applying flux by the foam wave method on the bottom surface of circuit boards and to the terminals of radio and electrical elements, and is an improvement of the known device according to the author. St. No. 1172663.

The purpose of the invention is to increase the reliability of the device for applying flux, as well as to remove excess flux and accelerate the conversion of foam into a liquid.

FIG. 1 shows a device for applying a flux; in fig. 2 shows section A-A in FIG. one; in fig. 3 is an electrical schematic diagram of a device for automatically controlling and maintaining the level of the flux.

In the housing 1, a bath 2 with a solution of the flux 3 is installed with the possibility of vertical mixing (fig. 1). A slotted nozzle 4, provided at the outlet with baffles 5, is located in the bath 2 with a solution of the flux 3 and is rigidly connected to the housing 1. Inside the nozzle 4 a foaming element 6 is mounted, the cavity 7 of which is connected to an air line (not shown). A brush 8 for removing excess flux is installed at the outlet of the device — and is rigidly connected to the housing 1. The bath 2 is closed on top of the grid 9 to accelerate the conversion of the foam into a liquid. Bath 2 is mounted on guide columns 10 (one column is conventionally shown) mounted in pan 11. Each of guide columns 10 is placed in sleeve 12 mounted on plate 13 of case 1. In the gap between column 10 and sleeve 12, tensioned balls, 14. The sensors 15 and 16 of the lower and upper position of the bath 2 are mounted inside the housing 1, and the limit stops 17 and 18 of the lower and upper position of the bath 2 are mounted on the pallet 11.

Bath 2 with a solution of flux 3 together with the pallet 11, mounted on columns 10, is spring-loaded spring 19 (Fig. 1 and 2). A part of the turns of the latter is screwed from one end into the nut 20, which is mounted in the plate 13 of the housing 1 for rotation. In the nut 20 are radial holes 21 under a special key. The pipe 22 is installed inside the spring 19 and is rigidly connected to its second end by means of a split ring 23 and bolts 24. The pipe 22 is equipped with a threaded bore 25 at one end, and a smooth bore 26 at the other end. key. The rod 28 is installed in the smooth hole 26 of the pipe 22, screwed into the threaded hole 25 of the pipe 22 and secured with a nut 29. The rod 28 by means of a spherical support 30 mounted in the tray 11 is in contact with the bath 2. The rod 28 is provided with a turnkey square shank 31.

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The sensor 15 (16) of the lower (upper) position of the bath 2 can be made, for example, in the form of a limit switch-microswitch (Fig. 1). The opening contact 32 (Fig. 3) of the sensor 15 of the lower position of the bath 2 is connected in series with the closing contact 33 of the sensor 16 of the upper position of the bath 2 in the supply circuit of the coil of the contactor 34 (actuator). The latter serves to automatically connect the supply network to either the pump for pumping the flux solution into the bath 2 from the tank, if the latter is located below the bath 2, or to the solenoid valve (spool) of the flux solution overflow into the bath 2 from the tank (not shown), if the latter is above bath 2. The closing contact 35 of the button “Flux supply is connected in parallel to the closing contact 33 of the sensor 16 and is bridged by the closing contact 36 of the contactor 34.

The button "Flux supply" is located on the front panel of the device control panel (not shown).

To control the air pressure in the line connected to the cavity 7 of the foaming element 6, and therefore, to control the height of the foam wave above the slit nozzle 4, the device is additionally equipped with a pressure switch (not shown). The opening contacts 37 and 38 of the pressure relay, which operate when the air pressure in the cavity 7 deviates, respectively, in the direction of decrease and increase, are connected in series to the supply circuit of the coil of the intermediate relay 39 (Fig. 3). The closing contact 40 of the intermediate relay 39 is connected in series to the power supply circuit of the electromagnet 41 of the pneumatic valve for switching on air into the cavity 7 of the foaming element 6.

To turn on the foam wave only at the moment of passage of the mounting plate 42, which is to be fluxed, above the slit nozzle 4, and consequently, to shorten the oxidation time of the flux solution, which oxidizes much faster in the foam cap above the foaming element 6, the device is additionally equipped with a foam switch waves mounted on the path of the circuit board 42 at the input of the device (not shown). The closing contact 43 of the foam wave switch is connected in series to the power supply circuit of the time relay 44. The closing contact 45 of the time relay 44 (opening with a time delay sufficient for the passage of the circuit board 42 above the slotted nozzle 4) is connected in series with the closing contact 40 of the intermediate relay 39 to the power supply circuit of the electromagnet 41 of the pneumatic valve for switching on air into the cavity 7 of the foaming element 6. Parallel to the closing contact 45 make contact 46 is connected

“Foaming. The latter is located on the front panel of a device control panel (not shown).

On the front panel of the control panel of the device, there are also indicator lights on the flux volume indicating: light 47 is the smallest; the light bulb 48 is about normal and the light bulb 49 is about the largest permissible volume of flux solution 3 in bath 2. Moreover, the closing contact 50 of the sensor 16 of the upper position of the bath 2 is connected to the power supply circuit of the lamp and 47, the closing contact 51 of the lower sensor 15 the position of the bath 2, and the disconnecting contacts 52 and 53 of the sensors 15 and 16 of the lower and upper position of the bath 2, respectively, are connected in series to the power supply circuit of the bulb 48.

In addition, sig10 are located on the front panel of the device control panel.

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put the load with the mass equal to the mass of the flux solution in the bath of the maximum allowable volume. In doing so, the bath 2 moves down along the guide columns 10, and the spring 19 is compressed. The distance from the edge of the housing 1 to the upper edge of the bath 2 (the lower position of the bath) is measured. Then in the bath 2 put the weight of the mass equal to the mass of the flux solution in the bath of the minimum allowable volume. In doing so, the bath 2 moves upward along the guide columns 10, and the spring 19 unfolds. The distance from the edge of the housing 1 to the upper edge of the bath 2 (the upper position of the bath) is measured. The difference in the heights of the lower and upper positions of the bath 2 is calculated. In the event that the differences in the heights of the lower and upper positions of the bath 2 are greater than the difference between the levels of the flux solution of the minimum and maximum allowable volumes, then the spring rigidity 19 is less than the necessary pressure bulbs. It is necessary to increase the rigidity of the pipes: the green light bulb 54 of the norm 19, reduce its working number to 55

the pressure of the red light is about the pressure deviation from the normal in the cavity 7 of the foaming element 6. Moreover, in the power supply circuit of the light bulb 54 there is a closing contact 56 of the 25 intermittent relay 39, and in the power supply circuit of the light bulb 55 there is a break contact 57 of the relay 39.

The mounting plate 42 to be fluxed is fixed in the process satellite on a transport device (conveyor) located above the flux application device.

The device works as follows.

To ensure a constant level of the flux solution 3 over the foaming element by screwing part of the coils of the spring 19 into the nut 20. In case the height difference between the lower and upper positions of the bath 2 is less than the difference between the levels of the flux solution of the minimum and maximum allowable volumes, the spring stiffness 19 is greater than necessary . It is necessary to reduce the stiffness of the spring 19, increase the working number of its turns by unscrewing part of the spring coils from the nut 20. Thus, part of the turns of the spring 19 is screwed in (or unscrewed) from one end of the spring to the nut 20, equaling the difference in height of the bath positions 2 flux solution, i.e. proportionality

Volume 6 during operation of the device (in spring spring 19 mass of the column of the solution of flux transfer from the bath 2 to the pore flux of a unit height. Similar to the surface of the circuit boards 42) it is necessary that the stiffness of the spring 19 be proportional to the mass of the pillar flux solution heights. The rigidity of the spring 19 is adjusted by changing the working cycle of the turns of the spring 19 by screwing (or unscrewing) a part of the turns of the spring 19 from one end of it into the nut 20. To do this, pour the flux solution 3 into the bath 2

the minimum allowable volume, pre-45 rod 28, in contact with the bath 2, in some way stopping the bath through the spherical support 30 and the tray 11, well 2 from moving on the guides by unscrewing (or screwing) it A lot of poured brew from a threaded hole 25 of the pipe 22 is applied. Thief flux and distance from the top chrome-B due to the fact that the flux solution 3

of the bath 2 to the level of the flux in the bath 2. The relatively fast evaporating and hardening liquid appears. It is polleregulated when the concentration of the flux solution or the flux brand changes, i.e. its specific density, as well as during operation of the device due to 40 aging (fatigue) of the spring 19. After the final calibration of the rigidity of the spring 19, the base height is set, i.e. the distance from the bottom surface of the circuit board 42 to the mirror solution of the flux 3 in bath 2 by means of additionally introduced

thereby adding the bath 2 with the flux solution 3 to the maximum allowable volume, measuring the mass of the filled flux solution and from the distance from the upper edge of the bath 2 to the level of the flux in the bath. The flux solution will lick the drain from bath 2 into the tank at the end of the work shift (drain pipe and tank not shown). To fill the bath with a solution of flux 3, it is necessary to fill it. Bath 2 rastormazhivayut. Calculate the 55 button “Feed the flux on the front panel, the difference between the levels of the flux solution of the control panel of the device control panel. With

This closes the contact 35 of the button “Flux supply connects the supply voltage and the maximum allowable volume. Next to bath 2 originally

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put the load with the mass equal to the mass of the flux solution in the bath of the maximum allowable volume. In doing so, the bath 2 moves down along the guide columns 10, and the spring 19 is compressed. The distance from the edge of the housing 1 to the upper edge of the bath 2 (the lower position of the bath) is measured. Then in the bath 2 put the weight of the mass equal to the mass of the flux solution in the bath of the minimum allowable volume. In doing so, the bath 2 moves upward along the guide columns 10, and the spring 19 unfolds. The distance from the edge of the housing 1 to the upper edge of the bath 2 (the upper position of the bath) is measured. The difference between the heights of the lower and upper positions of the bath 2 is calculated. In the event that the differences between the heights of the lower and upper positions of the bath 2 are greater than the difference between the levels of the flux solution of the minimum and maximum allowable volumes, then the rigidity of the spring 19 is less necessary than Dima. It is necessary to increase the rigidity of the spring 19, reduce the working number of its turns by screwing part of the turns of the spring 19 into the nut 20. In case the height difference between the lower and upper positions of the bath 2 is less than the difference between the flux levels of the minimum and maximum allowable volumes, the spring stiffness 19 more necessary. It is necessary to reduce the stiffness of the spring 19, increase the working number of its turns by unscrewing part of the spring coils from the nut 20. Thus, part of the turns of the spring 19 is screwed in (or unscrewed) from one end of the spring to the nut 20, equaling the difference in height of the bath positions 2 flux solution, i.e. proportionality

spring stiffness 19 to the mass of a single-height flux solution column. Similar to

spring stiffness 19 to the mass of a single-height flux solution column. Similar to

the rod 28 in contact with the bath 2 through the spherical support 30 and the pallet 11, by unscrewing (or screwing it) out of the threaded hole 25 of the pipe 22. In connection with the fact that the flux solution 3

adjustment is made by varying the concentration of the flux solution or the brand of flux, i.e. its specific density, as well as during operation of the device due to aging (fatigue) of the spring 19. After the final calibration of the rigidity of the spring 19, the base height, i.e. the distance from the bottom surface of the circuit board 42 to the mirror solution of the flux 3 in bath 2 by means of additionally introduced

There is a drain from bath 2 to the tank at the end of the work shift (the drain pipe and the tank are not shown). To fill the bath with 2 flux solution 3, it is necessary to press the button "Flux supply on the front panel of the device control panel. With

Press the button "Flux supply on the front panel of the device control panel. With

This closing contact 35 button "Flux supply connects the power supply for the same 10

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Link to the coil of contactor 34 along the circuit: "plus power supply, disconnecting contact 32 of sensor 15, closed contact 35 of the button" Feed flux of coil of contactor 34, "minus power supply. The contactor is activated, its closing contact 36 bypasses the closing contact 35 of the button “Flux supply. In addition, the closing contacts of the contactor connect the supply voltage to the pump or the solenoid valve (depending on the specific make-up of the device to charge the 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 spring 19 increases. Under the effect of increasing load, the spring 19 is compressed causing the bath 2 to move downwards. When fully filled with the flux solution 3, bath 2 last occupies the lowest position. In this case, the pusher acts on the drive element of the sensor 15 of the lower position of the bath 2. The sensor 15 is activated and opens the supply circuit of the roller of the contactor 34 with its opening contact 32. The latter returns to its original position and opens the power supply circuit of the pump (electromagnetic valve) with its closing contacts . The supply of the flux solution 3 to the bath 2 is stopped. In addition, the closing contact 51 of the sensor 15 of the lower position of the bath 2 closes the power supply circuit of the signal lamp 49. The glow of the latter on the front panel of the device control panel indicates the presence of a flux solution 3 in the bath 2 in the full maximum allowable volume.

When compressed air is supplied through the cavity 7 of the foaming element 6, the flux solution 3 inside the slotted nozzle 4 above the foaming element 6 made of porous ceramic foams air out of the pores of the foaming element 6 and rises above the brushes 5 of the slotted nozzle 4 The height of the foam wave depends on the amount of foam generated and is controlled by changing the pressure (flow rate) of compressed air supplied to the cavity 7 of the foaming element 6. The pressure switch included in the air line ode into the cavity 7 of the foaming element 6 is adjusted so that it is triggered by reducing the height of the foam wave less than the minimum allowable (contact 37 opens) and with increasing altitude, its opening contacts 37 and 38 sequentially close the power supply of the intermediate relay 39. Relay 39 its closing contact 40 is activated and turns on the power supply circuit of the electromagnet 41 of the pneumatic valve to turn on the compressed air into the cavity 7 of the expanding element b, and the closing contact 56 connects the lamp to the mains 54 ku green light indicating normal pressure and wave height of the foam within the permissible range. Otherwise, when the height of the foam wave is low or high, i.e. the height of the foam wave is not within acceptable limits, the pressure relay is activated and its opening contact 37 (low wave height) or opening contact 38 (high wave height) opens the power supply circuit of the intermediate relay 39. The closing contact 40 of the relay 39 opens the power supply circuit of the electromagnet 41 of the pneumatic valve, and the disconnecting contact 57 of the relay 39 connects to the mains supply a red light 55, indicating a deviation of pressure and height of the foam wave from the allowable limit.

The activation of the foam wave during the adjustment of the pressure switch is carried out by pressing the Foaming button located on the front panel of the device control panel. In this case, the electromagnet 41 of the pneumatic valve is connected to the supply voltage, the network along it: "plus the power source, closed contact 46 of the" Foaming button, closed contact 40 of the intermediate relay 39, electromagnet 41 of the pneumatic valve, "minus the power source. As a result, compressed air from the main through the pneumatic valve enters the cavity 7 of the foaming element 6 - a foam wave of the flux is formed above the slotted nozzle 4.

Vertical brushes 5 mounted at the exit of the slotted nozzle 4 are used to maintain a uniform level of the surface of the foam over the outlet of the slot nozzle 4 and uniform distribution of flux flux on the bottom surface of the circuit board 42. uniformity of cell sizes of the porous material of which the foaming element is made.

After performing these commissioning works, including calibrating the spring stiffness 19, exhibiting a base height 50 of bath 2 relative to the circuit board 42, pouring a solution of the flux 3 and setting the pressure switch to a predetermined limit of the foam wave height, the device for applying the flux is ready for operation.

Mounting plate 42, subject to flux30

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the foam wave cells are larger than the maximum to -55, fixed in the technology satellite (contact 38 is opened). In the service room on the conveyor, when approaching the device, when the height of the foam wave in the environment of the application of the flux affects the paths of the permissible, the pressure switch in the original switch. The latter is triggered and

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the state, its opening contacts 37 and 38 sequentially close the power supply circuit of the intermediate relay 39. Relay 39 is activated and its closing contact 40 prepares to turn on the power supply circuit of the electromagnet 41 of the pneumatic valve to turn on the compressed air into the cavity 7 of the foaming element b, and the short contact 56 connects to the power supply network light bulb 54 green light, indicating a normal pressure and the height of the foam wave within acceptable limits. Otherwise, when the height of the foam wave is low or high, i.e. the height of the foam wave is not within acceptable limits, the pressure relay is activated and its opening contact 37 (low wave height) or opening contact 38 (high wave height) opens the power supply circuit of the intermediate relay 39. The closing contact 40 of the relay 39 opens the power supply circuit of the electromagnet 41 of the pneumatic valve, and the disconnecting contact 57 of the relay 39 connects to the mains supply a red light 55, indicating a deviation of pressure and height of the foam wave from the allowable limit.

The activation of the foam wave during the adjustment of the pressure switch is carried out by pressing the Foaming button located on the front panel of the device control panel. In this case, the electromagnet 41 of the pneumatic valve is connected to the supply voltage, the network along it: "plus the power source, closed contact 46 of the" Foaming button, closed contact 40 of the intermediate relay 39, electromagnet 41 of the pneumatic valve, "minus the power source. As a result, compressed air from the main through the pneumatic valve enters the cavity 7 of the foaming element 6 - a foam wave of the flux is formed above the slotted nozzle 4.

Vertical brushes 5 mounted at the exit of the slotted nozzle 4 are used to maintain a uniform level of the surface of the foam above the outlet of the slot nozzle 4 and uniform distribution of flux on the bottom surface of the circuit board 42. uniformity of cell sizes of the porous material of which the foaming element is made.

After performing these commissioning works, including calibrating the spring stiffness 19, exhibiting the base height 0 of bath 2 relative to the circuit board 42, pouring the flux solution 3 and setting the pressure switch to a predetermined limit of the foam wave height, the flux applying device is ready for operation.

Mounting plate 42 subject to flux0

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5, it is fixed in the technology satellite, the closing contact 43 connects the coil of the time relay 44 to the mains. The time relay is activated and its closing contact 45 connects the electromagnet 41 of the pneumatic valve to the mains. As a result, the compressed air from the main through the pneumatic valve enters the cavity 7 of the foaming element 6 — a foam wave of flux is formed above the slotted nozzle 4. The flux is applied by a foam wave by contacting the bottom surface of the circuit board 42, which performs translational motion, with the crest of the foam wave. As a result of this contact, the flux bubbles are destroyed and the soldering places are covered with a thin layer of the flux composition. When the flashing plate 42 passes over the brush 8 installed at the device exit, flux efflux is removed from the surface of the circuit board, which flows back into the bath 2. In addition, the circuit board 42 passing over the device creates pressure on the the foaming of the foam destroys its lower layers resting on the grid 9, the cell sizes of which are somewhat smaller than the average diameter of the foam bubbles, which contributes to the accelerated conversion of the foam back into liquid and prevents overflow of the bath 2 with the foamed flux solution 3 After the passage of the circuit board 42 over the closing device - the contact 45 of the time relay 44, which opens with a time delay, opens and disconnects the supply network from the electromagnet 41 of the pneumatic valve. The supply of compressed air to the cavity 7 of the foaming element 6 ceases until the next circuit board 42 approaches the device.

As the flux solution 3 is transferred to the surface of the circuit boards 42, the volume of the flux solution 3 in the bath 2 decreases. The load acting on the spring 19 is also reduced. As a result, the bath 2 rises along the guide columns 10, and the level of the flux solution 3 in the bath 2 and the slit nozzle 4 above the foaming element 6 remains constant. Moreover, the device responds to relatively small changes in the volume of the flux solution 3 due to its low resistance to movement, low friction forces in the ball guides (column 10 - ball 14 - sleeve 12), which remain almost unchanged during operation of the device. By this, the device achieves the constancy of the height of the combinated wave, and, consequently, the thickness of the applied flux layer on the surface of the board does not change during the operation of the device. The reliability of the device increases.

The bath 2 in the operating state of the device is in an intermediate position. However, none of the limiters 17 and 18 does not affect the sensors 15 and 16. Pos0

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The latter ones are in the initial state and, by their opening contacts 52 and 53, successively close the power supply circuit of the signal lamp 48. The glow of the latter on the front panel of the device control panel indicates the presence of a flux solution 3 in 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 limiter 18 acts on the drive element of the sensor 16 of the upper position of the bath 2. The sensor 16 is triggered and by its closing contact 33 connects the supply voltage to the coil of the contactor 34 via the circuit: “plus power supply, disconnecting contact 32 of the sensor 15, closed contact 33 of the sensor 16 contactor coil, minus power supply. The contactor operates, its closing contact bypasses the closing contact 33 of sensor 16. In addition, the closing contacts of the contactor connect the supply voltage either to the pump or to the solenoid valve. The bath 2 is filled with the flux solution 3 until the sensor 15 of the lower position of the bath 2 is activated.

At the same time, when the upper position of the bath 2 sensor 16 is triggered, the power supply circuit of the warning light 48 opens by means of the disconnecting contact 50 of the sensor 16, and the power supply of the warning light 47 is closed by the closing contact 50 of the sensor 16. in bath 2 in the smallest allowable amount.

The presence of the sensor 15 automatic control of the lower position of the bath 2 with the flux solution 3 excludes the possibility of the flux solution getting to the upper side of the circuit board 42, since the possibility of overflow of the flux solution 3 into the bath exceeding the allowable volume is excluded.

The presence of the sensor 16 automatic control of the upper position of the bath 2 with the flux solution 3 eliminates the possibility of the lower surface of the circuit board 42 not being wetted with the flux solution, since the possibility of the flux solution 3 being consumed below the permissible value is excluded.

The sensors 15 and 16 of the automatic control of the lower and upper position of the bath 2 with the flux solution 3 are mounted inside the housing 1 of the device. Contact with aggressive media - flux solution 3 and its vapors is completely excluded. This increases the reliability of the sensors 15 and 16.

Claims (3)

Invention Formula . Device for applying flux on the author. St. No. 1172663, distinguished by that, in order to increase the reliability of the device, it is equipped with a pipe installed in each elastic element and rigidly connected to one end with a nut into which a part of the other end of the elastic element is screwed, with a threaded rod installed in the hole in the pipe, and located under the bath guide columns. 2. A device according to claim I, characterized in that, in order to remove excess flux, it is provided with an additional brush disposed at the outlet of the bath. . 3. A device according to claim 1, characterized in that, in order to accelerate the conversion of the foam into a liquid, it is provided with a grid located above the bath. . R 15 (Fig. 2) h; “Foaming W