JPH05200541A - Method and device for discharging cream solder - Google Patents

Abstract

PURPOSE:To apply cream solder uniformly on a substrate by detecting the remaining amount of the cream solder in a cylinder-shaped container and adjusting the pressure of compressed air to be supplied into the container in accordance with the remaining amount. CONSTITUTION:Compressed air is supplied to the cream solder that is filled in the cylinder-shaped container, and the cream solder is discharged from a discharging nozzle 19 by the air pressure. At this time, the remaining amount of the cream solder in the container 21 is detected. Then, in accordance with the remaining amount, the pressure of the compressed air to be supplied to the container 21 is adjusted by a pressure adjusting device 23, and the cream solder is discharged. The amount of the cream solder remaining in the cylinder- shaped container 21 is detected by a ultrasonic measuring machine. Thus, soldering performance is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for discharging cream solder, and in particular, a constant amount of cream solder is always discharged regardless of the remaining amount of cream solder filled in a cylindrical container. The present invention relates to a method and an apparatus for discharging cream solder, which enables application of non-existent cream solder and improves soldering performance.

[0002]

2. Description of the Related Art As a method of soldering to a substrate, a reflow soldering method is mainly used in which many electronic components are simultaneously soldered by mounting electronic components on a substrate having a soldering portion coated with cream solder and heating the same. It is used for soldering parts.

As a method of applying the cream solder to the substrate, a so-called metal mask in which a punch hole is formed at a position corresponding to the cream solder application portion of the substrate is prepared, and the metal mask is overlaid on the substrate and placed on the metal mask. The printing method of applying cream solder was used. On the other hand, due to the recent miniaturization of electronic components, the density of lead terminals is further increased, the area of the soldering portion is reduced, and the electronic components having a lead terminal pitch of only about 0.5 mm can be soldered. Is strongly requested.

However, according to the conventional printing method, since the cream solder is applied, the holes formed in the metal mask must be made small, and when the cream solder is printed on a large number of substrates, the holes are not formed. It has a drawback that it is clogged and an application failure of cream solder occurs.

Further, it is difficult to find the defective application portion at the time of applying the cream solder before soldering, and it will be found in the substrate inspection step after the soldering is completed, so that the work efficiency is poor and the defective substrate is repaired. There was a drawback that it required a lot of man-hours. Further, it is necessary to prepare a metal mask for each substrate having a different pattern and set it on the printing machine, which has a drawback that setup change is difficult.

As a method for solving the above-mentioned drawbacks, a method and an apparatus (a cream solder dispenser) for ejecting cream solder from a nozzle mounted on a three-dimensional moving device to apply it to a substrate have been proposed. The required amount of cream solder applied per location of a miniaturized electronic component is about several mg. On the other hand, according to the conventional discharge applying method, the amount of cream solder discharged from a nozzle is the distance between the nozzle and the substrate. Caused a large variation, the warp of the substrate,
If there is a bend or the like, variation in the distance between the nozzle and the substrate due to this causes variation in the coating amount.

Further, in a discharge device for applying a pressure of compressed air to a cream solder filled in a commonly used cylindrical container to discharge it, even if compressed air having a constant pressure is supplied to the cylindrical container. , The discharge amount changes depending on the remaining amount of cream solder filled in the cylindrical container,
There is a drawback that the amount of cream solder applied varies and soldering cannot be performed uniformly.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate the above-mentioned drawbacks of the prior art. The object of the present invention is to provide a cream solder residual quantity detecting device for cream solder in a cylindrical container. The remaining amount of the cream solder is detected and the pressure of the compressed air supplied to the cylinder-shaped container is adjusted according to the remaining amount of the cream solder, so that a constant amount of cream solder is always maintained regardless of the remaining amount of the cream solder in the cylindrical container. This is to improve the soldering performance by discharging the cream solder and evenly applying it to the substrate.

[0009]

In summary, according to the method of the present invention (claim 1), compressed air is supplied to the cream solder filled in the cylindrical container, and the cream solder is discharged by the pressure of the compressed air. In the method for discharging cream solder to be discharged from, the remaining amount of the cream solder in the cylindrical container is detected, and the pressure of the compressed air supplied to the cylindrical container is adjusted according to the remaining amount of the cream solder. The cream solder is discharged. Further, the device of the present invention (claim 2) is a cream solder ejecting device for supplying compressed air to a cylindrical container filled with cream solder and ejecting the cream solder from a cream solder ejecting nozzle by the pressure of the compressed air. , A cream solder residual quantity detecting device for detecting the residual quantity of the cream solder in the cylindrical container, and adjusting the pressure of the compressed air supplied to the cylindrical container according to the measurement result of the cream solder residual quantity detecting device. And a pressure adjusting device that operates.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. The cream solder applying device 3 according to the present invention includes a cream solder residual amount detecting device 40 and a pressure adjusting device 23.

First, referring to FIGS. 1 and 2, the basic structure of the cream solder coating device 1 will be described. The three-dimensional moving device 2 is for moving the cream solder discharging device 3 to an arbitrary position in the three-dimensional space. And X on the base 6
The direction moving device 8 is fixed, and the Y direction moving device 9 is fixed to the X direction moving table (not shown) of the X direction moving device 8 to drive the X direction moving device 8 to move the Y direction moving device 9 to the X direction. It is designed to move in the direction.

The Y-direction moving table 10 of the Y-direction moving device 9 is also provided.
A Z-direction moving device 11 is fixed to the Z-direction moving device 11, and a DC servomotor 12 provided in the Z-direction moving device 11 is operated to rotate a ball screw mechanism (not shown) to move the Z-direction moving table 13 in the Z-direction. It is designed to be moved to.

The X-direction moving device 8 and the Y-direction moving device 9
Also, like the Z-direction moving device 11, a drive mechanism including a DC servo motor and a ball screw mechanism is built in, and X or Y can be activated by operating each DC servo motor.
The movable portion is configured to move in the direction.

Since the independent three-dimensional moving device 2 is provided with the independent DC servomotors as described above, it is possible to linearly move at high speed between two points in the three-dimensional space.
For example, moving at a maximum speed of 1500 mm / sec,
It is possible to stop at a predetermined position with a positional accuracy of plus or minus 0.02 mm.

A first moving table 15 to which a motor 14 is fixed is fixed to the Z-direction moving table 13, and a second moving table 16 is provided in a dovetail groove (not shown) formed in the first moving table 15. Slidably fitted and guided by a dovetail groove (not shown)
You can move in any direction.

A lead screw 19 that is screwed into a female screw (not shown) formed on the second moving table 16 is connected to the rotary shaft 18 of the motor 14, and the motor 14 is operated to move the lead screw 19. The second moving table 16 is rotated to move in the Z direction.

The cream solder ejecting device 3 is for ejecting the cream solder 41 from the cream solder ejecting nozzle 19 and applying it to the substrate 20.
A cylindrical container 21 filled with is attached to the second moving table 16 with the cream solder discharge nozzle 19 attached to the tip thereof facing downward, and the rear end of the cylindrical container 21 is connected via a pipe 22. By adjusting the pressure of compressed air supplied from a compressed air supply source (not shown), the cylindrical container 21
A pressure adjusting device 23 for supplying the compressed air is supplied to the cylindrical container 21 by adjusting the pressure of the compressed air according to a command from the control device 5, and the pressure in the cylindrical container 21 is increased to the cream solder 41. The pressure of compressed air is applied to the cream solder discharge nozzle 19 to discharge the cream solder. The pressure adjustment of the compressed air will be described in detail later.

The non-contact type length measuring device 4 is for measuring the height of the cream solder application planned portion 20a of the substrate 20, and a well-known laser displacement gauge 4 as an example of the non-contact type length measuring device is used. It is mounted on the second moving table 16 adjacent to the cylindrical container 21.

The laser beam emitted from the laser displacement meter 4 is aimed at a position directly below the cream solder discharge nozzle 19 of the substrate 20, and the laser beam emitted from the laser displacement meter 4 is to be applied to cream solder. The reflected light from the portion 20a is condensed on a position detection element (not shown) by a lens (not shown), the distance to the cream solder application planned portion 20a is measured, and the measurement result is controlled by the control device via the electric cord 23. 5 is transmitted.

The spot diameter of the laser beam is 70 to 90.
Since the response time is about 0.1 msec, which is extremely short, the distance to the cream solder application scheduled site 20a can be measured instantly.

The control unit 5 is a cream solder applying unit 1.
DC servo motor, motor 14, pressure regulator 23,
A computer 28 including a central processing unit 24, an input / output port 25, an external storage device 26, and the like for controlling each part of the laser displacement meter 4 and the like, and a keyboard for inputting command signals to the computer 28. 29 and a display device 30 for displaying the processing result.

The structure of the Z direction control device of the cream solder dispenser 3 will be described. The measurement result from the laser displacement meter 4 is input to the input / output port 25 by the electric cord 23, and predetermined arithmetic processing is performed based on the input signal. DC is applied
A drive signal to the servo motor and the motor 14 is transmitted through the electric cord 31 to operate the DC servo motor and the motor 14, and the cream solder ejecting device 3 is moved in the Z direction so as to move the board 20 and the cream solder ejecting nozzle 19 to each other. It is configured to control the distance between and to be a predetermined distance.

The substrate 20 is mounted on the base 6 by the three-dimensional moving device 2
A substrate transfer device (not shown) for transporting the substrate 20 below the substrate and a substrate holding table 32 for horizontally holding and holding the transported substrate 20 are provided, and the substrate 20 having a size of 60 × 90 mm to 385 × 510 mm is provided. It is conveyed at a speed of 1.5 to 2.5 m / sec and is fixedly held.

Further, a reference stand 33 having a contact 33a is fixed to a predetermined portion of the base 6 so that the tip of the cream solder discharge nozzle 19 can be brought into contact with the contact 33a to set a reference position in the Z direction. Is becoming The cream solder applicator 1 is also provided with a switch 34 for manually operating each part.

Next, referring to FIG. 3, the cream solder remaining amount detecting device 40 and the pressure adjusting device 23 of the cream solder ejecting device 3, which are the main parts of the present invention, will be described. The cream solder residual amount detecting device 40 is for detecting the residual amount of the cream solder 41 filled in the cylindrical container 21, and is, for example, the ultrasonic length measuring device 40 mounted in the cylindrical container 21. , Ultrasonic waves are emitted toward the surface of the cream solder 41 as indicated by the broken line in the figure,
The distance from the surface of the cream solder 41 is measured by receiving the reflected wave (in the direction of arrow A) from the surface and measuring the time from the emission of the ultrasonic wave to the reception.

Further, the cream solder remaining amount detecting device 40 and the input / output port 25 of the computer 28 are electrically connected by an electric cord 42, and the measurement result is input to the computer 28 to perform a predetermined arithmetic processing. It is designed to control each part. If the distance can be measured, the consumption amount of the cream solder 41, in other words, the remaining amount can be easily calculated by multiplying the sectional area of the cylindrical container 21.

The pressure adjusting device 23 is for adjusting the pressure of compressed air supplied from a compressed air supply source (not shown) and supplying it to the cylindrical container 21, and is, for example, a known pressure adjusting valve 23. It is mounted in the cylindrical container 21 and is electrically connected to the computer 28 by an electric cord 43.

A valve mechanism (not shown) is operated by a command signal from the computer 28 to adjust the pressure of the compressed air supplied in the direction of the arrow B from a compressed air supply source (not shown) and send the compressed air to the cylindrical container 21. The pressure in the container 21 is increased so that the pressure of compressed air acts on the cream solder 41 in the direction of arrow C, and the cream solder 41 is discharged from the cream solder discharge nozzle 19.

Then, the method of the present invention uses the cylindrical container 21.
In the method of discharging cream solder in which compressed air is supplied to the cream solder 41 filled in the container and the cream solder 41 is discharged from the cream solder discharge nozzle 19 by the pressure of the compressed air, the cream solder 41 in the cylindrical container 21 is
The remaining amount of the cream solder 41 is detected, and the pressure of the compressed air supplied to the cylindrical container 21 is adjusted according to the remaining amount of the cream solder 41,
This is a method of discharging the cream solder 41.

The present invention is configured as described above,
The operation will be described below. 1 to 3, the position coordinates of the cream solder application planned site 20a of the substrate 20 and the substrate 2 at the time of discharge are controlled by the control device 5 as preparatory work.
The distance (set distance) between 0 and the cream solder ejection nozzle 19, for example, 1 mm is stored.

This storage operation may be manually input from the keyboard 29, or the data stored in the floppy disk (not shown) may be read from a floppy disk drive (not shown) and stored. .. Then, the cream solder discharge nozzle 19 is operated by manually operating the switch 34 to bring it into contact with the contactor 33a of the reference table 33, thereby storing the Z-direction reference position of the cream solder discharge nozzle 19 and ending the preparation work.

After the board 20 is carried by a carrying device (not shown) and horizontally fixed and held on the board holder 32, when the operation of the cream solder coating apparatus 1 is started, the controller 5
After the three-dimensional moving device 2 operates to move the cream solder ejecting device 3 to the first cream solder application planned site 20a according to the data stored in the above, the laser displacement meter 4 applies a laser beam to the cream solder application planned site. 20a is irradiated to measure the distance to the cream solder application planned site 20a, and the measurement result is sent to the control device 5 via the electric cord 23.
Communicate to.

The spot diameter of the laser beam is 70 to 90.
Very small as μm, and response time is about 0.1 msec
Therefore, it is possible to measure an arbitrary position of the cream solder application planned site 20a in an extremely short time.

Then, it is determined whether the measured distance is equal to the preset distance. If they are not equal, it is determined whether the measured distance is greater than the set distance. When the measured distance is larger than the set distance, it is determined that the position of the cream solder ejecting device 3 is too high, and the drive signal from the control device 5 is DC.
The DC servomotor 12 and the motor 14 are transmitted to the servomotor 12 and the motor 14 via an electric cord 31.
Is driven to move the cream solder discharge device 3 downward, and the distance between the substrate 20 and the cream solder discharge nozzle 19 is controlled to be a set distance, for example, 1 mm.

If the measured distance is not greater than the set distance, it is determined that the position of the cream solder ejecting device 3 is too low, and the drive signal from the control device 5 is sent to the DC servo motor 12 and the motor 14 by an electric cord. Then, the DC servomotor 12 and the motor 14 are operated to move the cream solder discharge device 3 upward, and the distance between the substrate 20 and the cream solder discharge nozzle 19 is set to a set distance, for example, 1 mm. Control to be.

As described above, after the distance from the substrate 20 to the cream solder discharge nozzle 19 is corrected to the set distance, the pressure of the compressed air supplied from the compressed air supply source (not shown) is adjusted by the pressure adjusting device 23. It is adjusted and fed into the cylindrical container 21, and the pressure in the cylindrical container 21 is increased to discharge the cream solder 41 from the cream solder discharge nozzle 19 in a predetermined amount in the direction of the arrow D and apply it to the substrate 20.

Referring also to FIG. 4, the discharge state of the cream solder 41 will be described in detail. In step S ₁ , the ultrasonic wave length measuring device 40 emits ultrasonic waves toward the surface of the cream solder 41, and the cream solder 41 is discharged. Reflected wave from the surface of 41 (arrow A
Direction) and the time from the emission of the ultrasonic wave to the reception thereof is measured to measure the distance to the surface of the cream solder 41.

Then, in step S ₂ , the measurement result is input to the computer 28 and processed according to a predetermined calculation process to calculate the remaining amount of the cream solder 41 in the cylindrical container 21. In step S ₃ , an appropriate supply air pressure corresponding to the remaining amount of the cream solder 41 is obtained.

When a certain amount of the cream solder 41 is discharged from the cream solder discharge nozzle 19 by applying compressed air to the surface of the cream solder 41 in the direction of arrow C, the remaining amount of the cream solder 41 shown by the phantom line in FIG. The amount of energy required for ejection differs when the amount is large and when the residual amount of the cream solder 41 shown by the solid line is small, and it is necessary to change the pressure of the compressed air to act.

Generally, the proper supply air pressure consumes a large amount of energy to flow a large amount of cream solder 41 having high viscosity when the remaining amount of cream solder 41 is large. Therefore, a large amount of energy must be supplied. Therefore, a relatively high air pressure is required, and when the remaining amount is small, a predetermined amount of cream solder 41 can be discharged even with a low air pressure.

Since the air is a compressive fluid, the proper supply air pressure varies not only with the remaining amount of the cream solder 41 but also with the volume of the cylindrical container 21. The relationship with the proper supply air pressure required for discharging is experimentally obtained in advance to create data, and the data is stored in the external storage device 2 of the computer 28.
It is convenient to store it in 6.

Next, in step S ₄ , the pressure adjusting device 23 is operated to adjust the air pressure to an appropriate value, and it is sent into the cylindrical container 21 in step S ₅ , and the air pressure is applied to the surface of the cream solder 41 in the direction of arrow C. Is applied to the substrate 20 by discharging a fixed amount from the cream solder discharge nozzle 19 in the direction of the arrow D.

As described above, a fixed amount of cream solder 41
To finish the cream solder application to the first cream solder application scheduled site 20a, the three-dimensional movement device 2 is operated to move the cream solder dispense apparatus 3 to the next cream solder application scheduled site 20a, and The same operation is repeated for all the portions 20a where the cream solder is to be applied, and the application of the cream solder to the substrate 20 is completed.

The discharge speed of the cream solder 41 is
One time is about 0.5 seconds, and as described above, the cream solder 41
The amount of the cream solder 41 remaining is detected for each discharge, and the proper supply air pressure is applied to the surface of the cream solder 41, and the distance between the substrate 20 and the cream solder discharge nozzle 19 is plus or minus 0.02 mm with respect to the set value. Since the amount of the cream solder 41 is ejected after being corrected with the accuracy of, the variation in the amount of ejection of the cream solder 41 is extremely small, within ± 15%, and the cream solder 41 can be uniformly applied to the substrate 20. Further, the number of cream solder application planned sites 20a that can be stored is at least three.
Since it can be set to 000 points, a practically sufficient number of points can be stored.

In the above embodiment, the cream solder remaining amount detecting device has been described as an ultrasonic length measuring device, but the cream solder remaining amount detecting device is not limited to the ultrasonic length measuring device and may be an optical length measuring device. It may be a length measuring instrument or the like.

[0046]

As described above, according to the present invention, the amount of cream solder remaining in the cylindrical container is detected by the cream solder remaining amount detecting device, and the compression is supplied to the cylindrical container according to the remaining amount of cream solder. Since the air pressure is adjusted, there is an effect that a constant amount of cream solder can always be discharged and uniformly applied to the substrate regardless of the remaining amount of cream solder in the cylindrical container. As a result, there is an effect that the soldering performance can be improved.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a cream solder applicator.

FIG. 2 is a main part perspective view showing the configuration of a cream solder coating device.

FIG. 3 is a longitudinal sectional view of a main part showing the configuration of the cream solder ejecting apparatus.

FIG. 4 is a flowchart showing a routine of operation of the cream solder ejecting apparatus.

[Explanation of symbols]

3 Cream Solder Discharge Device 19 Cream Solder Discharge Nozzle 21 Cylinder-shaped Container 23 Pressure Adjusting Device 40 Ultrasonic Wave Length Measuring Device as an Example of Cream Solder Remaining Amount Detection Device 41 Cream Solder

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // H05K 3/34 H 9154-4E

Claims (3)

[Claims] 1. A method of discharging cream solder, comprising supplying compressed air to cream solder filled in a cylindrical container and discharging the cream solder from a cream solder discharge nozzle by the pressure of the compressed air. Discharging the cream solder by detecting the remaining amount of the cream solder, and adjusting the pressure of the compressed air supplied to the cylindrical container according to the remaining amount of the cream solder. Method. 2. A cream solder discharge device for supplying compressed air to a cylindrical container filled with cream solder and discharging the cream solder from a cream solder discharge nozzle by the pressure of the compressed air. Of the remaining amount of cream solder, which detects the remaining amount of cream solder, and a pressure adjusting device that adjusts the pressure of the compressed air supplied to the cylindrical container according to the measurement result of the remaining amount of cream solder. A device for ejecting cream solder, characterized by being provided. 3. An ultrasonic wave detecting device for detecting the residual quantity of the cream solder by ultrasonically measuring a surface position of the cream solder contained in the cylindrical container, by the ultrasonic quantity detecting device. The device for discharging cream solder according to claim 2, which is a length measuring device.