JP2000141599A - Printer having press injecting head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pattern of a good shape even in the case of a small mask opening by pushing a mask to a base plate irrespective of a filling force of a solder paste to bring the mask into close contact with the plate when the paste is filled from a press injecting head in the opening. SOLUTION: A lip 13 is mounted inside an opening of a press injecting head 11 having a lip holder 24 for discharging a solder paste 2 so that its end is slightly projected from an end of the holder 24 toward a mask, the head 11 is lowered by a pushing force 26 of a vertical shaft of the head 11 to bring the lip 13 into contact with the mask 3 to be deformed. In this case, the mask 3 is not brought into contact with the holder 24, and the end of the holder 24 is brought into contact with the mask 3 in the case of further lowering. Since the holder 24 is lower elastic than the lip 13, the mask 3 is brought into contact with a base plate 5 irrespective of the force 26, a pneumatic pressure is operated at the paste 2 to fill the paste 2 in the opening 6, and hence good printing pattern can be formed, thereby prolonging the service time of the lip 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing machine for applying a solder paste to a substrate such as a printed circuit board, and more particularly, to a printing machine having a press-fit head for filling a solder opening into a mask opening using pressure. Related to printing presses.

[0002]

2. Description of the Related Art In order to mount (fix) electronic components such as a semiconductor device, a resistor, and a capacitor on a substrate to realize a desired electronic circuit, for example, a mask and a substrate are fixed at predetermined positions, 2. Description of the Related Art A printing machine is used in which a squeegee is brought into contact with a mask and a squeegee is moved so that the mask and the substrate are continuously contacted to fill a solder opening into a mask opening. Further, in the printing press using the squeegee, since the solder paste moves so as to roll on the mask, deterioration such as oxidation is apt to progress, and recently, a printing press having a press-fit head for filling the solder paste with compressed air or the like is used. Machine is being used.

[0003] In a conventional press-fitting head, a portion called a lip contacts a mask. This lip is provided outside the opening from which the solder paste of the press-fit head is discharged, and the tip of the lip has a gap before and after in the moving direction of the press-fit head. Only to prevent pressure from escaping. When the opening at the tip of the lip moves over the mask opening, the solder paste is filled by pressure.

[0004]

In printing, it is important to improve the adhesion between the substrate and the mask by pressing the mask from above, and to correct the warpage of the substrate. It is essential. Furthermore,
In recent years, mask openings have become smaller along with miniaturization of electronic components, and the filling power of the solder paste must be further increased in order to stably fill the openings.

Therefore, in the press-fitting head, the pressure applied to the solder paste is increased, and the press-fitting head is pressed against the mask so as to be in close contact with the mask so as to prevent pressure loss due to solder paste leakage. However,
In a conventional press-fit head, this pressing is performed via a lip, and a lip having a higher elasticity than the press-fit head is used. Must be weakened. Then, the adhesion between the mask and the substrate is impaired,
The problem that the solder paste leaks from the gap between the mask and the substrate and spreads over the substrate, causing bleeding and greatly affecting the shape of the solder paste print pattern, and the higher the pressure applied to the solder paste, the worse the print pattern shape becomes There is. Therefore, an object of the present invention is to provide a printing press provided with a press-fitting head capable of obtaining a print pattern having a good shape even with a small mask opening.

[0006]

In order to achieve the above object, according to the present invention, when a solder paste is filled into a mask opening from a press-fitting head, the mask is pressed against a substrate irrespective of the filling force of the solder paste. The press-fit head is provided with means for bringing the mask and the substrate into close contact with each other. As a result, the mask and the substrate can be sufficiently adhered to each other, and a print pattern having a good shape can be obtained even in the case of a small mask opening.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view illustrating the structure of a printing press equipped with a press-fit head according to the present invention, FIG. 2 is a side view illustrating the structure of the printing press illustrated in FIG. , 8 is the upper table, 9 is the frame, 10
Is a mask frame, 11 is a press-fit head, 12 is a press-fit head vertical axis, 14 is a press-fit head pressing cylinder, 15 is a printing block, 16 is a ball screw, 17 is a motor, 18 is a board receiver, 22 is a rail, and 23 is a linear bearing. It is.

In both figures, the mask 3 is fixed to a mask frame 10, and the mask frame 10 is fixed to a frame 9. The motor 17 and the rail 22 are installed on the upper table 8, and the upper table 8 is fixed to the frame 9. A ball screw 16 is coupled to the motor 17, and the ball screw 16
The ball nut (not shown) is fixed to the printing block 15. The board receiver 18 fixes the board 5 and is fixed to the frame 9. A printing block 15 is supported on the rail 22 via a linear motion bearing 23. The printing block 15 has a press-fit head pressing cylinder 1
4 is fixed, and the press-fit head vertical shaft 12 as its output shaft
, A press-fit head 11 is fixed.

The substrate 5 is fixed on the substrate receiver 18 in an appropriate positional relationship with the mask 3. The press-fit head 11 is moved to a position on the left side of the drawing with respect to the mask opening (not shown),
By applying compressed air to the press-fit head pressing cylinder 14, the press-fit head vertical shaft 12 is lowered, the tip of the press-fit head 11 is brought into contact with the mask 3, and the mask 3 and the substrate 5 are brought into contact. When air pressure is applied to the press-fit head 11 at the same time as the motor 17 is rotated, the solder paste in the press-fit head 11 moves while applying pressure. At this time, since there is no mask opening in the opening at the tip of the press-fit head, the filling of the solder paste does not occur. When the opening at the tip of the press-fit head moves over the mask opening, filling of the solder paste occurs, and when the press-fit head opening passes, the filling ends. Then, press-fit head 11
The mask 3 and the substrate 5 are separated from the portion where the has passed, and a solder paste pattern is formed on a pad provided on the upper surface of the substrate 5 so as to face the mask or the opening, and printing is completed.

FIG. 3 shows a press-fit head 1 used in the printing press shown in FIG.
FIG. 4 is a view showing a second embodiment of the press-fit head 11. 3 and 4, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, 2 is a solder paste, and 4 is provided on the upper surface of the substrate 5 so as to face the mask opening 6. 13, a lip fixed to the lip holder 24, a casing 25 for fixing the lip holder 24 and serving as a container for the solder paste 2, a pressing force 26 for pressing the mask 3 against the substrate 5, and a soldering force 27 for printing. The air pressure acting on the paste 2, 28 is the air pressure 2
7, a paste pressure generated in the solder paste 2; 29, a press bar movably supported by a casing 25 by supporting means (not shown); 30, a press bar pressing force generated by operating air pressure of a cylinder 32; Is a cylinder fixed to the flange of the casing 25. The lower end of the piston rod 32a is in contact with the descending amount adjusting screw 31.
34 is a tension spring provided between the flange portion of the casing 25 and the press bar 29, and 35 is a lip pressing plate.

In the first embodiment shown in FIG. 3, the lip 13 is attached inside the opening of the press-fitting head composed of the lip holder 24 for discharging the solder paste, and the tip of the lip 13 is connected from the tip of the lip holder 24 to the mask. It is slightly out (extending). When the press-fit head 11 is moved down by the pressing force 26 of the press-fit head vertical shaft 12 to come into contact with the mask 3, the lip 13 first comes into contact with the mask 3 and deforms (deflects), but the mask 3 does not contact the substrate 5. When the press-fit head 11 is further lowered, the tip of the lip holder 24 comes into contact with the mask 3. The lip holder 24 has a lower elasticity than the lip 13 and is made of a material that is not deformed. Therefore, the mask 3 and the substrate 5 are brought into contact (close contact) with the deformation of the tip of the lip 13 kept constant. In other words, regardless of the magnitude of the pressing force 26, the deformation of the tip of the lip 13 can be kept constant, and the air pressure 27 acts on the solder paste 2 to fill the mask opening, so that good printing conditions and solder paste can be obtained. And the life of the lip 13 is prolonged.

The second embodiment shown in FIG. 4 is characterized in that the press-fit head 11 is provided with a press bar 29 in order to bring the mask 3 and the substrate 5 into contact. The two press bars 29 shown in FIG.
The member is a member that transmits a force for bringing the substrate 5 into close contact with the substrate 5 and is a separate member that is divided into front and rear portions. In the embodiment shown in FIG. 4, the front press bar 29 is pushed down by the piston rod 32a in the press-fit head moving direction 7 shown by the arrow, and the rear press bar is pulled up by a tension spring. This is because the influence on the pattern shape caused by sliding the upper surface of the mask 3 with the rear press bar 29 after filling the mask opening 6 with the solder paste 2 is considered. That is, the rear press bar 29 does not come into contact with the filled solder paste 2 and adhere to and wipe off the press bar 29, so that the filling amount is not reduced.

The amount of deformation of the lip 13 can be adjusted by adjusting the amount of lowering of the press bar 29 by the piston rod 32a by the amount of adjusting screw 31 so that the sealing property of the lip 13 can be adjusted. Also, the amount of deformation of the lip 13 can be adjusted by the magnitude relationship between the pressing force 26 for pressing the mask 3 against the substrate 5 and the press bar pressing force 30 generated by the operating air pressure of the cylinder 32. That is, when the press bar pressing force 30 is larger than the pressing force 26, the amount of deformation of the lip 13 is determined by the amount of lowering of the piston rod 32a determined by the lowering amount adjusting screw 31, and is not affected by the pressing force 26.
On the other hand, when the press bar pressing force 30 is smaller than the pressing force 26, the piston rod 32a is returned by the reaction force of the substrate 5 via the mask 3 by the pressing force 26, and as a result, the lowering amount of the piston rod 32a , The amount of deformation of the lip 13 changes.

Here, a conventional example will be described with reference to FIG. In FIG. 7, the casing 25 and the lip holder 24
Are joined together without a gap, and the lip holder 24 and the lip 13 are held down by screws with the lip holding plate 35, and are joined together without a gap. At this time, the space created by the casing 25, the lip holder 24 and the lip 13 is
There is an opening only in the upper part of the lip 13 and the tip of the lip 13, and the space is filled with the solder paste 2.

When an air pressure 27 is applied, a paste pressure 28 is generated in the solder paste 2. In the conventional example, the pressing force 26 must be equal to or higher than the force required to bring the mask 3 into contact with the substrate 5 and at the same time, the sealing property at the tip of the lip must be ensured by the paste pressure 28. When a pressing force 26 for bringing the mask 3 into contact with the substrate 5 is applied, the tip of the lip 13 is deformed as shown in FIG. 7, so that the pressing force 26 cannot be increased.
Then, the adhesion between the mask 3 and the substrate 5 is reduced, and the solder paste 2 leaks from between the mask 3 and the substrate 5 to cause bleeding. In addition, the contact area between the mask 3 and the lip 13 is increased, and the surface pressure is reduced, so that the sealing performance is deteriorated, and the solder paste 2 leaks from the tip of the lip 13. If the pressing force 26 is further increased in order to improve the sealing property, the deformation of the lip 13 increases, and not only the life is shortened,
A vicious cycle occurs in which the sealing property at the tip of the lip 13 is reduced, and good printing conditions cannot be found.

FIG. 5 shows a third embodiment of the present invention, which is characterized in that a press bar 29 is provided between both lips 13 in order to bring the mask 3 and the substrate 5 into contact. The press bar 29 is connected to the casing 25, but has a perforated structure so that the solder paste 2 can pass through. In this embodiment, the lip 13 on one side always passes after the press bar 29 has passed regardless of the direction of movement of the press-fit head. As a result, similarly to the embodiment shown in FIG. 4, the air pressure 27 is applied to fill the mask opening 6 with the solder paste 2 and then the press bar 2
Since the solder paste 9 does not slide on the upper surface of the filled solder paste 2, the press bar 29 does not affect the pattern shape when the filled solder paste 2 is removed.

A fourth embodiment of the present invention shown in FIG. 6 is different from the embodiment shown in FIG.
A ring 33 and a tension spring 34 are provided.

The lip holder 24 and the casing 25 are connected by a linear motion rail (not shown), and O
A ring 33 is provided. The lip holder 24 is pulled upward by a tension spring 34, and its upper limit position is determined by a descending amount adjusting screw 31. That is, the lowering amount adjusting screw 31 is screwed to the lip holder 24, and the upper end thereof penetrates the opening of the flange portion of the casing 25, and the nut 36, which sandwiches the flange portion of the casing 25 from above and below. 37 is screwed. When no air pressure is applied to the cylinder 32, the lip holder 24 is pulled upward by the tension spring 34, and the upper limit position of the lifting is determined by the lower nut 37. When air pressure is applied to the cylinder 32, the rod 32a is pushed out, and the lip holder 24 is moved in the direction in which the tension spring 34 is extended.
To move. At this time, the nut 36 above the descending amount adjusting screw 31 functions as a stopper that defines the lower limit. In this state, the press bar 29 is pressed against the mask 3 and air pressure 27 is applied to the press-fitting head to fill the solder opening 2 into the mask opening 6 and perform printing.

In this embodiment, similarly to the embodiment of FIG. 4, the pressing force of the lip 13 can be controlled by the pressing force of the press bar 29 and the operating air pressure applied to the cylinder 32.

In each of the embodiments shown in FIGS. 4, 5 and 6, the press-fit head 11 is provided with a member (press bar 29) for transmitting a force for bringing the mask 3 and the substrate 5 into close contact with each other. However, as in the conventional example of FIG. 7, the lip 13 may be provided outside the tip (lip holder 24) forming an opening for discharging the solder paste 2.

[0021]

As described above, according to the present invention,
Even in the case of a small mask opening, a print pattern having a good shape can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing a printing press according to an embodiment of the present invention.

FIG. 2 is a side view of the printing press shown in FIG.

FIG. 3 is a view showing a press-fit head of the printing press shown in FIG.

FIG. 4 is a view showing a press-fit head according to a second embodiment of the present invention.

FIG. 5 is a view showing a press-fit head according to a third embodiment of the present invention.

FIG. 6 is a view showing a press-fit head according to a fourth embodiment of the present invention.

FIG. 7 is a diagram illustrating a press-fit head of a conventional printing press.

[Description of Signs] 2 ... Solder paste, 3 ... Mask, 4 ... Pad, 5 ... Board, 6 ... Mask opening, 11 ... Press-fit head, 13 ... Lip, 18 ... Board receiver, 24 ... Lip holder, 25 ... Casing .

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Haruo Mikami 13-17 Nakagawa, Adachi-ku, Tokyo F-term in Hitachi Techno Engineering Co., Ltd. (reference) 2C035 AA06 FC10 FD05 FD15 FD17 FD27 FD35 5E319 BB05 CD29

Claims (4)

[Claims] 1. A press-fit head which fixes a mask and a substrate in a desired positional relationship, and moves the press-fit head in parallel with the upper surface of the mask so that the contact between the mask and the substrate is continuously performed. Air pressure is applied to the inside, the lip of the tip opening of the press-fit head is brought into close contact with the mask by the air pressure, and the solder paste in the press-fit head is filled into the opening provided in the mask, and the mask and the substrate are separated by separating the mask and the substrate. In the printing machine for transferring the solder paste, when filling the solder opening into the mask opening from the press-fitting head, press-fitting the mask against the substrate irrespective of the filling force of the solder paste to press-fit the mask and the substrate. A printing press provided with a press-fit head, the printing press being provided on the head. 2. A press-fit head, which fixes a mask and a substrate in a desired positional relationship and moves the press-fit head in parallel with the upper surface of the mask so that the mask and the substrate are continuously contacted. Air pressure, the lip of the tip opening of the press-fit head is brought into close contact with the mask by the air pressure, and the solder paste in the press-fit head is filled into the opening provided in the mask, and the mask is separated from the board by soldering. In a printing machine that transfers paste, a lip that extends toward the mask is provided inside the opening from which the solder paste of the press-fit head is discharged, and the lower end of the press-fit head is pressed against the mask to bring the mask and substrate into close contact with each other. A press equipped with a press-fit head, characterized in that the deformation of the tip of the lip is kept constant irrespective of the force. 3. A press-fit head while fixing the mask and the substrate in a desired positional relationship and moving the press-fit head in parallel with the upper surface of the mask so that the contact between the mask and the substrate is made continuously. Air pressure, the lip of the tip opening of the press-fit head is brought into close contact with the mask by the air pressure, and the solder paste in the press-fit head is filled into the opening provided in the mask, and the mask is separated from the board by soldering. In a printing machine that transfers paste, a lip that extends toward the mask is provided outside or inside the opening for discharging the solder paste of the press-fit head, and when the solder paste is filled from the press-fit head into the mask opening, the press-fit head presses the mask. A member for transmitting the force for bringing the mask into close contact with the substrate is provided in the press-fit head, and the solder paste of the press-fit head is discharged by the member. That the printing press leading end portion forming the opening is provided with a press-fit head is characterized in that to avoid direct contact with the mask. 4. The printing press equipped with a press-fit head according to claim 1, wherein the lip has a higher elasticity than the press-fit head.