JPH05200543A - Device for applying cream solder - Google Patents

Abstract

PURPOSE:To enable the uniform application of cream solder to a substrate by bringing a contactor into contact with the tip of a nozzle for discharging the cream solder and by setting the reference position in Z direction of the nozzle. CONSTITUTION:By the use of a discharging device 3 of the cream solder, the cream solder is discharged from a nozzle 19 filled with the cream solder and applied to the substrate 20. A warm discharging device 3 is mounted on a three dimensional moving device 2, and is moved to the X-direction which is parallel with the plane of the substrate, to the Y-direction which is orthogonally crossed with the X-direction in its plane and to the Z-direction which orthogonally crossed with the XY-direction. A reference base 33 having the contactor 33a is fixed on a pedestal 6 of the three dimensional moving device 2. By bringing the contactor 33a into contact with the tip of the nozzle 19 in the discharging device 3 of the cream solder, the reference position of the Z-direction for the discharging nozzle 19 is set. Thus, the operating efficiency is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cream solder applicator, and more particularly to a cream solder container which can automatically set a vertical (Z direction) reference position of a container filled with cream solder. The present invention relates to a cream solder applicator that facilitates installation and greatly improves workability.

[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 the electronic components on a substrate having a soldering portion coated with cream solder and heating them. It is used for soldering electronic components.

Conventionally, as a method of applying the cream solder to the substrate, a so-called metal mask having a hole 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. A printing method of applying cream solder on a mask has been used. On the other hand, due to the recent miniaturization of electronic components, the density of lead terminals has been further increased, the area of the soldering portion has been reduced, and the electronic components having a pitch of the lead terminals of only about 0.5 mm can be soldered. There is a strong desire to do so.

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 a 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 completion of soldering, so that the work efficiency is poor and the defective substrate can be repaired. It has a drawback that it requires 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 a device (cream solder dispenser) for discharging cream solder from a nozzle mounted on a three-dimensional moving device and applying it to a substrate have been conventionally proposed. The required amount of cream solder to be discharged from one location of a miniaturized electronic component is about several mg. However, according to the conventional coating method, the amount of cream solder to be discharged from a nozzle is greatly dependent on the distance between the nozzle and the substrate. However, if the substrate is warped or bent, the coating amount may vary due to a change in the distance between the nozzle and the substrate, and soldering cannot be performed uniformly.

Furthermore, when the cream solder in the cylinder-shaped container is consumed, it is necessary to replace it with a new cylinder-shaped container filled with cream solder. It was difficult to mount it at exactly the same height as the cylindrical container, and it was unavoidable that some mounting error occurred.

This mounting error in the height direction causes a variation in the discharge amount of the cream solder from the nozzle as it is, and the discharge amount changes before and after the replacement of the cylindrical container, so that the soldering cannot be performed uniformly. There was a flaw.

Further, since the mounting density of electronic parts on the board increases, the number of cream solder application sites is extremely large, and it is practically difficult to check the application state of cream solder to each of these application sites one by one. Often, the defective application of the cream solder is often found for the first time in the board inspection process after the soldering is completed, but it is late in the discovery in the board inspection process.
There is a drawback in that the production efficiency is lowered because there is no other way but to discard the substrate as a defect or to repair it by spending a lot of man-hours.

Further, for the above-mentioned reason, it is necessary to control the dimension of the cylindrical container in the height direction and to mount it. However, in order to mount the cylindrical container with a small mounting error, careful work is required. It had the drawback of requiring skill.

[0011]

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 move a cylindrical container filled with cream solder three-dimensionally. After mounting on the device, the cream solder discharge nozzle of the cylinder-shaped container is brought into contact with the contact of the reference table to detect the position of the cream solder discharge nozzle in the height direction. Correcting the mounting error so that the cream solder can always be discharged with the gap between the board and the cream solder discharging nozzle being constant, and also to allow the cream solder to be applied uniformly to the board. Is.

Another object is to make the cylinder-shaped container replacement work much easier than in the past, so that no skill is required, and the time required for the cylinder-shaped container replacement is greatly shortened to improve work efficiency. It is to let.

Still another object is to eliminate defective application of cream solder, reduce the defective rate of the substrate, and improve the production efficiency.

[0014]

SUMMARY OF THE INVENTION In summary, the present invention provides a cream solder ejecting device which is filled with cream solder and ejects the cream solder from a cream solder ejecting nozzle to apply the cream solder to a substrate. A three-dimensional moving device that moves in an X direction parallel to the plane of the substrate, a Y direction orthogonal to the X direction in the plane, and a Z direction orthogonal to the X direction and the Y direction, and a base of the three-dimensional moving device. And a reference stand having a contactor which is fixed to the table and sets the Z-direction reference position of the cream solder discharge nozzle by making contact with the tip of the cream solder discharge nozzle of the cream solder discharge device. It is a thing.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. 1 to 3, a cream solder applying device 1 according to the present invention includes a three-dimensional moving device 2, a cream solder discharging device 3, and a reference table 33.

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 the X-direction moving device 8 is fixed to the base 6 and
The Y-direction moving device 9 is fixed to an X-direction moving table (not shown) of the direction moving device 8 to drive the X-direction moving device 8 to move the Y-direction moving device 9 in the X-direction.

The Y-direction moving table 10 of the Y-direction moving device 9 is also provided.
Has a Z-direction moving device 11 fixed thereto. The 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,
It is configured to move the movable portion in the X or Y direction by operating each DC servo motor.

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

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 slidable in a dovetail groove 15a formed in the first moving table 15. They are fitted together and can be moved in the Z direction (arrow A or B direction) by being guided by the groove 15a.

A lead screw 19 which 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 operate the lead screw 19. The second moving table 16 is rotated to move in the arrow A or B direction.

The cream solder ejecting device 3 ejects the cream solder from the cream solder ejecting nozzle 19 so that the substrate 20
A cylindrical container 21 filled with cream solder is mounted on the second moving table 16 with the cream solder discharge nozzle 19 mounted at the tip thereof facing downward, At the rear end of the container 21, a compressed air adjusting device 23 that adjusts the pressure of compressed air supplied from a compressed air supply source (not shown) via a pipe 22 and supplies the compressed air to the cylindrical container 21 is installed. 5
The compressed air pressure is adjusted according to the command from the air conditioner and sent into the cylindrical container 21, and the pressure inside the cylindrical container 21 is increased so that the compressed solder is acted on by the compressed air and discharged from the cream solder discharge nozzle 19. It has become.

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 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 portion to be applied with cream solder of the laser beam emitted in the direction of the arrow C is set. The reflected light from 20a is condensed on a position detecting element (not shown) by a lens (not shown), the distance to the cream solder application planned site 20a is measured, and the measurement result is sent to the controller 5 via the electric cord 23. It is designed to be transmitted to.

Further, the spot diameter of the laser beam is 70 to 90 μm, the response time is extremely short at about 0.1 msec, and the distance to the cream solder application planned site 20a can be instantly measured. ..

The controller 5 is a cream solder applying device 1
DC Servo Motor, Motor 14, Compressed Air Conditioner 2
3, a computer 28 including a central processing unit 24, an input / output port 25, an external storage device 26, and the like, for inputting a command signal to the computer 28 for controlling each part of the laser displacement meter 4 and the like. Keyboard 29
And a display device 30 for displaying the processing result.

Next, the structure of the Z-direction control device of the cream solder ejecting device 3 will be described.
To the DC servo motor and the motor 14, and the drive signal to the DC servo motor and the motor 14 is transmitted through the electric cord 31 to operate the DC servo motor and the motor 14, The solder ejecting device 3 is moved in the directions of arrows A and B to control the distance between the substrate 20 and the cream solder ejecting nozzle 19 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 designed to be conveyed and fixedly held at a speed of 1.5 to 2.5 m / sec.

The main part of the present invention will be described below.
A reference stand 33 having a contact 33a made of a conductive material is fixed to a predetermined portion of the base 6 by a bolt 34, and the reference stand 33 is connected to the input / output port 25 by an electric cord 35, and is attached to the contact 33a. When the tip of the cream solder discharge nozzle 19 comes into contact, it is detected and a detection signal is transmitted to the computer 28 so that the position in the height direction (Z direction) of the cream solder discharge nozzle 19 can be known and the reference position can be set. ing. In addition, the cream solder applicator 1
A switch 34 for manually operating each part is provided.

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 a floppy disk (not shown) may be read from a floppy disk drive (not shown) and stored. ..

Next, the switch 34 is manually operated to move the cream solder discharge nozzle 19 in the direction of the arrow B, and then, as shown in FIG.
As shown by the broken line in FIG.

Cream solder discharge nozzle 19 and contact 33
When it comes into contact with a, for example, the cream solder discharge nozzle 19
Is obtained, and the contact is detected when the voltage of the contactor 33a, which has been in a high voltage state by being supplied with electricity until then, is lowered, and the detection signal is transmitted to the computer 28 through the electric cord 35. Then, the position of the cream solder discharge nozzle 19 in the Z direction is stored, and this position is stored as a reference position thereafter, and the preparatory work is completed.

Cream solder discharge nozzle 19 and contact 33
The position detection accuracy in the Z direction by contact with a is about 0.02.
Since it is about mm, it can be detected with extremely high accuracy.
Therefore, when 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 applying apparatus 1 is started, the controller 5 stores it. According to the data, first, the three-dimensional movement device 2 is operated to move to the first cream solder application scheduled site 20a, and then the laser beam is irradiated from the laser displacement meter 4 to the cream solder application scheduled site 20a to schedule the cream solder application. The distance to the part 20a is measured, and the measurement result is transmitted to the control device 5 via the electric cord 24.

Then, the Z direction position of the cream solder discharge nozzle 19 is calculated by comparing the measurement result with the stored reference position. The spot diameter of the laser beam is 7
It is very small, 0 to 90 μm, and the response time is about 0.
Since it is 1 msec, the cream solder application site 20
Any position of a can be measured in a very short time.

Then, it is judged whether or not 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 judged that the position of the cream solder ejecting device 3 is too high, and the drive signal from the control device 5 sends the electric code 31 to the DC servo motor 12 and the motor 14. The cream solder discharge device 3 is moved downward by driving the DC servo motor 12 and the motor 14 so that the distance between the substrate 20 and the cream solder discharge nozzle 19 becomes a set distance, for example, 1 mm. To control.

If the measured distance is not larger 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 code. 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 based on the stored reference position to be a set distance, for example, 1 mm,
The pressure of the compressed air supplied from a compressed air supply source (not shown) is adjusted by the pressure adjusting device 23 and sent into the cylindrical container 21, and the pressure in the cylindrical container 21 is increased to discharge the cream solder from the cream solder discharge nozzle 19. A fixed amount is ejected and applied onto the substrate 20.

The state in which the pressure of compressed air is applied to the cream solder in the cylindrical container 21 to discharge the cream solder will be described in detail. When the amount of cream solder remaining in the cylindrical container 21 is large, The energy required to discharge the cream solder is different when the remaining amount is low,
It is necessary to change the pressure of compressed air to operate.

Generally, the appropriate supply air pressure consumes a large amount of energy for flowing a large amount of cream solder having a high viscosity when the remaining amount of cream solder is large, and therefore a large amount of energy must be supplied. When a relatively high air pressure is required and the remaining amount is small, a predetermined amount of cream solder 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 cream solder but also with the volume of the cylindrical container 21, and the remaining amount of cream solder and a fixed amount of cream solder can be discharged. It is convenient to empirically obtain the relationship with the required proper supply air pressure in advance to create data, and to store the data in the external storage device of the computer 28.

Then, an ultrasonic wave length measuring device (not shown) emits an ultrasonic wave toward the surface of the cream solder in the cylindrical container 21, receives a reflected wave from the surface of the cream solder, and receives the ultrasonic wave. By measuring the time from the emission to the reception of the cream solder, the distance to the surface of the cream solder is measured, the measurement result is input to the computer 28, processed according to a predetermined calculation process, and the cream solder in the cylindrical container 21 is processed. The remaining amount is calculated, and the appropriate supply air pressure corresponding to the remaining amount of cream solder is obtained from the above-mentioned appropriate supply air pressure table. Then, the pressure adjusting device 23 is operated to send the compressed air having the proper supply air pressure into the cylindrical container 21, and a predetermined amount of cream solder is discharged from the cream solder discharge nozzle 19 to be applied to the substrate 20.

As described above, after a fixed amount of cream solder is discharged to finish the cream solder application to the first cream solder application scheduled site 20a, the three-dimensional moving device 2 is operated to operate the next cream solder application scheduled site. The cream solder ejecting device 3 is moved to 20a, and the same operation is repeated thereafter. In this way, all the parts to be applied with cream solder 20
The application of cream solder to a is completed.

Here, when the cream solder in the cylinder-shaped container 21 is completely consumed during the application of the cream solder, the switch 34 is manually operated again after replacing with the new cylinder-shaped container 21 filled with the cream solder. Is operated to move the cream solder discharge nozzle 19 in the direction of arrow B to bring it into contact with the contact 33a, and the position of the cream solder discharge nozzle 19 in the Z direction is detected.

The computer 28 compares the reference position stored during the preparatory work with the position of the new cylindrical container 21, calculates the difference, and corrects this value in the subsequent work to correct the cream solder. The discharge nozzle 19 is controlled in the Z direction.

That is, even if the cream solder discharge nozzle 19 is mounted at a slightly different position due to replacement, the distance between the substrate 20 and the cream solder discharge nozzle 19 is exactly the same as before the cylinder-shaped container 21 was replaced. For example, 1
Since the cream solder is ejected from the cream solder ejection nozzle 19 to the substrate 20 while being controlled to a value of mm, the ejection amount of the cream solder is always constant and uniform application can be performed.

As described above, the replacement work of the cylindrical container 21 becomes much easier than the conventional one, so that no skill is required, and the time required for the replacement of the cylindrical container 21 is greatly shortened to improve the working efficiency. You can

The discharge speed of the cream solder is about 0.5 second each time, and as described above, the remaining amount of the cream solder is detected every time the cream solder is discharged, and the appropriate supply air pressure is applied to the surface of the cream solder. At the same time, since the distance between the substrate 20 and the cream solder discharge nozzle 19 is corrected and discharged with an accuracy of ± 0.02 mm with respect to the set value, the variation in the discharge amount of cream solder is extremely small within ± 15%. Thus, it is possible to apply it uniformly on the substrate 20. Further, the number of cream solder application planned sites 20a that can be stored can be at least 3000 points, and a practically sufficient number of points can be stored.

[0050]

According to the present invention, after the cylindrical container filled with the cream solder as described above is attached to the three-dimensional moving device, the cream solder discharge nozzle of the cylindrical container is brought into contact with the contact of the reference table. Since the position in the height direction of the cream solder discharge nozzle is detected by the above, the mounting error due to the mounting of the cylindrical container is corrected to keep the gap between the substrate and the cream solder discharge nozzle constant. Has the effect of discharging the cream solder, and has the effect of uniformly applying the cream solder to the substrate.

Further, since the work of exchanging the cylindrical container is much easier than the conventional one, no skill is required, and the time required for exchanging the cylindrical container can be greatly shortened to improve the working efficiency. is there.

Further, since the defective application of the cream solder can be eliminated, there is an effect that the defective rate of the substrate can be reduced and the production efficiency 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 front view of the cream solder applicator showing a state in which the cream solder discharge nozzle is brought into contact with a contact to detect the position of the cream solder discharge nozzle in the Z direction.

[Explanation of symbols]

 1 Cream Solder Application Device 2 Three-Dimensional Moving Device 3 Cream Solder Discharge Device 6 Base 19 Cream Solder Discharge Nozzle 20 Substrate 33 Reference Base 33a Contactor

Claims (1)

[Claims] A cream solder ejecting device which is filled with cream solder and ejects the cream solder from a cream solder ejecting nozzle to apply the cream solder to a substrate, and an X direction parallel to a plane of the substrate, which is equipped with the cream solder ejecting device, A three-dimensional moving device that moves in the Y direction orthogonal to the X direction in the plane and in the Z direction that is orthogonal to the X direction and the Y direction, and the cream solder ejecting device fixed to the base of the three-dimensional moving device. A cream solder applicator, comprising: a reference stand having a contactor for setting a Z-direction reference position of the cream solder discharge nozzle by bringing the tip into contact with the tip of the cream solder discharge nozzle.