JP7311736B2 - Screen printer equipped with a vacuum squeegee mechanism - Google Patents

Description

The present invention relates to removal of air remaining in a printing member printed using a screen formed by perforating a steel plate, a screen formed of polymer threads, or a screen formed of a film having openings.

2. Description of the Related Art In the fields of manufacturing electronic parts, forming bumps, mounting electronic parts on substrates, etc., there is a method of printing printed matter such as ink, solder paste, and resin mold using a screen printer.

FIG. 6 shows an example of a conventional screen printing method for printing a printing member. FIG. 6A shows air trapping after the squeegee is raised. By moving the squeegee 20a in the direction of arrow C, the filling of the printing member into the openings of the substrate 18 and the screen 4 is completed. 15 separates between screen 4 and squeegee 20a. The tip of the solder paste 15 on the screen 4 side draws air L into the solder paste 15 when it falls over the screen 4 .

FIG. 6B shows the state after the squeegee 20b is lowered. When the solder paste 15 is printed on the new substrate 18, the squeegee 20b descends in the direction of arrow P and starts moving in the direction of arrow Q when it contacts the screen 4 surface. As the solder paste 15 rotates in the direction of the arrow N, the solder paste 15 moves while entraining the air L1, and fills the opening E of the screen 4 and the opening F of the substrate 18 with the solder paste 15 .

FIG. 6C shows printing of the solder paste 15 by moving the squeegee 20b. Since the squeegee 20b envelops part of the air in the opening E of the clean 4 and the opening of the substrate 18 during printing, air M and the squeegee 20b move in the opening E of the clean 4 and the opening of the substrate 18. Due to the air L1 that is sometimes entrained, it remains in the substrate opening F as air L2. As a result, when the diameter of the openings of the screen or the diameter of the openings of the film is made smaller due to the formation of bumps or the like, the above-described air in the openings makes accurate quantitative printing of the printing member difficult.

FIG. 6(D) shows that the air M and L2 remain in the solder paste 15 in the board opening F after the squeegee 20b is moved, and FIG. 6(E) shows the screen 4 and the board 18 after printing. It shows that the air M and L2 remains in the opening F as an air reservoir even after separating the air.

FIG. 7 shows part of the main configuration of a screen printer used for printing ink, solder paste, and fluid resins. The main equipment of this screen printer is housed in chamber 25 . The screen 4 also includes a printing method using a film, and the head 29 is provided with squeegees 20b and 20a. Vertical drives 28a and 28b are provided for movement in the directions of arrows da and db. On the other hand, the movement of the head 29 in the arrow C or B direction is performed by the horizontal drive section 30 . A printing unit 24 is composed of a printing table 23 for fixing the substrate 18 and a printing table elevating unit 31 .

When the squeegee 20a in FIG. 7 moves in the direction of arrow C, it moves while rotating the printing member 15 (see FIG. 6B) to print on the opening of the screen 4 (see E and F in FIG. 6). As a printing method for reducing the effect of void generation due to the air, a printing method has been introduced in which the printing section 24 is surrounded by a chamber 25 and the air in the chamber 25 is decompressed by a vacuum pump 27 as shown in FIG. (For example, refer to Document 1).
The pressure inside the chamber 25 is reduced, and then the printing valve 26 is opened to return the inside of the chamber 25 to the atmospheric pressure, and the printing member 15 is pushed.

However, when the pressure in the chamber 25 is reduced, if the printing member 15 contains a solvent having a boiling point that cannot be suppressed for volatilization, it becomes difficult to maintain the stability of the characteristics of the printing member. Printing in the chamber 25 under reduced pressure, opening the valve 26 after printing is completed, and pressing the printing member 15 with air takes several tens of seconds to return from the reduced pressure environment to the atmospheric pressure environment. The thixotropic nature of the viscosity of the member 15 changing over time cannot be expected to force the printing member 15 into place. Therefore, a solder paste for printing under reduced pressure has also been developed (see, for example, Patent Document 2).

JP-A-2004-167709 JP 2014-210291 A

In screen printing, when a printing member such as ink, solder paste, or fluid resins is printed, printing is performed using a resin, rubber, or metal squeegee on the upper surface of a screen or film. Apertures are formed in the screen or film at positions coinciding with the apertures in the substrate. It is difficult to evenly fill the printing member to the bottom of the opening of the substrate due to the side resistance of the opening, the air in the opening, and the air entrained in the printing member. When the printing member is printed in the opening of the substrate, two squeegees provided in the printing machine are alternately printed for each substrate. At this time, since the squeegee is separated from the screen surface or the film surface, entrainment of air occurs during the printing process. , a so-called void occurs. These voids cause variations in the volume of the electronic component electrodes when the substrate electrodes are formed. In addition, in forming bumps and the like, it becomes a factor that makes it impossible to form uniform bump heights. The present invention has been made to solve such a problem, and an object of the present invention is to provide a solution for suppressing the generation of voids.

In order to suppress voids, it is preferable to print the printing member under reduced pressure with little air, but if the printing member contains a solvent with a boiling point that cannot be suppressed from volatilizing under reduced pressure, it is difficult to maintain the properties of the printing member. becomes. The problem can be solved by a printing method in which only the opening between the screen or film and the substrate is decompressed while the printing member is kept at atmospheric pressure or above atmospheric pressure, and the lifting operation of the squeegee for each substrate to be printed is eliminated.

In order to achieve the above object, the screen printer of the present invention comprises a printing table on which a substrate to be printed is placed, a squeegee for sliding on the surface of a screen or film in contact with the surface of the substrate to be printed, and A screen printer that performs printing by filling openings formed in the screen or film with a printing material using the squeegee, wherein the screen is Alternatively, a vacuum wall forming a space that isolates a part of the surface of the film from the outside, a partition wall for partitioning the space formed by the vacuum wall, and a partition wall provided on an end surface of the vacuum wall and the screen or A vacuum chamber and a filling chamber which are formed by a sealing mechanism that is adjacent to or in contact with the surface of the film, the squeegee provided on the end face of the partition wall and in contact with the surface of the screen or film, the vacuum wall and the partition wall. The filling chamber is filled with the printing member, the gas in the vacuum chamber is decompressed , the filling chamber is formed by the partition wall, and the filling chamber is formed with a plurality of the filling chambers. A piston capable of applying pressure to the printing member is incorporated in the chamber, and a passage is formed in the partition wall between the plurality of filling chambers so that the printing member can be moved to another filling chamber by the pressure of the piston. ing.

Further, in the screen printing machine having the above configuration, the vacuum squeegee mechanism has a drive function capable of moving in parallel and perpendicular directions with respect to the printing table, and the vacuum wall includes a direction of parallel movement and a Independent vacuum chambers are formed on the counter-advancing direction side , and a plurality of the filling chambers are arranged between the advancing direction-side vacuum chamber and the anti-advancing direction side vacuum chamber, and the advancing direction-side vacuum chamber and the above- described Each of the vacuum chambers on the opposite direction of travel can be connected with a valve that can be switched between an evacuation device and a pressurizing device capable of pressurizing to the atmosphere or higher than the atmospheric pressure.

Further, in the screen printing machine having the above configuration, the valve is connected to the vacuum exhaust device in the traveling direction side vacuum chamber, and at the same time, the anti-advancing direction side vacuum chamber can be pressurized to the atmosphere or higher than the atmospheric pressure . It can be a switching valve that can be switched to and from the pressurizing device.

Further, in the screen printing machine having the above configuration, a paste stirrer for stirring the printing member can be added to the plurality of filling chambers.

Further, in the screen printing machine having the above configuration, a printing member supply port for replenishing the printing member from the outside can be added to the plurality of filling chambers.

Further, in the screen printing machine having the above configuration, the printing members in different filling chambers can be mixed through the passages formed in the partition wall by the movement of the piston.

Further, in the screen printing machine having the above configuration, the printing member moved in the passage can be agitated by the solder paste agitator by changing the pressure in the filling chamber due to the movement of the piston.

Moreover, in the screen printer having the above configuration, the squeegee can be made of metal, rubber, resin, or a composite configuration thereof.

Moreover, in the screen printer having the above configuration, the seal mechanism may be a labyrinth seal.

Moreover, in the screen printing machine having the above configuration, the sealing mechanism can be a roller or a boat-shaped blade.

Further, in the screen printing machine having the above configuration, a flat recovery plate is provided for preventing the printing member from falling from the filling chamber when the vacuum squeegee mechanism moves relative to the printing table in the vertical direction. the collecting plate is provided above the screen or film and can be close to or in contact with the sealing mechanism, and the collecting plate is adsorbed to the sealing mechanism by evacuating the gas in the vacuum chamber; Both the vacuum squeegee mechanism and the collection plate can be moved vertically relative to the screen or film .

Further, the method of the present invention comprises a printing table on which a substrate to be printed is placed, a squeegee for sliding on the surface of a screen or film in contact with the surface of the substrate to be printed, and the squeegee facing the printing table. and a driving mechanism for moving a part of the surface of the screen or film in a screen printing machine that performs printing by filling openings formed in the screen or film with the printing member using the squeegee. A vacuum wall forming a space for isolating the area from the outside, a partition wall for partitioning the space formed by the vacuum wall, and a partition wall provided on the end surface of the vacuum wall and in proximity to or in contact with the surface of the screen or film. A vacuum squeegee comprising a sealing mechanism, the squeegee provided on the end surface of the partition wall and in contact with the surface of the screen or film, and a vacuum chamber and a filling chamber formed by the vacuum wall and the partition wall. The filling chamber is filled with the printing member, the gas in the vacuum chamber is evacuated or pressurized, and the filling chamber is formed by the partition walls to form a plurality of the filling chambers. has a built-in piston that can apply pressure to the printing member, and the partition wall between the plurality of filling chambers is formed with a passage through which the printing member can move to another filling chamber by the pressure of the piston, A printing method for printing on the substrate to be printed by moving a vacuum squeegee mechanism parallel to the printing table.

INDUSTRIAL APPLICABILITY The present invention can remove air confined in a printing member in screen printing and prevent air from being mixed in, and is highly effective in improving voids. The function of continuously decompressing the opening, filling the printing member, and pressurizing enables the printing member to be filled into an opening with a large aspect ratio or a fine opening while suppressing the entrainment of air.

It is a figure which shows one Example of a structure of the vacuum squeegee mechanism by this invention. FIG. 8 is a view showing another embodiment in which both sides of the vacuum chamber are configured with rollers in the configuration of the vacuum squeegee mechanism according to the present invention; FIG. 10 is a diagram showing another embodiment in which both sides of the vacuum chamber are configured with blades in the configuration of the vacuum squeegee mechanism according to the present invention; FIG. 10 is a diagram showing another embodiment in which both sides of the vacuum chamber are configured with blades in the configuration of the vacuum squeegee mechanism according to the present invention; FIG. 4 is a diagram showing a screen replacement method according to the present invention; It shows entrapment of air by conventional printing, the process and the residual state of air. 1 shows a schematic diagram of a conventional printing press under reduced pressure. FIG.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. FIG.

FIG. 1 is a configuration diagram showing an embodiment according to the present invention, showing a vacuum squeegee mechanism 1 and its peripheral equipment. Spaces partitioned by partition walls 12, 13, and 14 are filled with the printing members 7a and 7b. Vacuum chambers 1a and 1b are formed outside the partition walls 12 and 14, and the vacuum chambers 1a and 1b are isolated from the outside by vacuum walls 5a and 5b. The partition walls 12, 13 and 14 are provided with metal, rubber or resin squeegees 8a, 8b and 8c, and the vacuum walls 5a and 5b are provided with labyrinth seals 3a and 3b to resist the inflow of air. Printing members 7a and 7b are filled between the partition walls 12 and 13 and between the partition walls 13 and 14, respectively, and have pistons 9a and 9b respectively driven by piston drivers 10a and 10b. A pressure change can be applied to 7a and 7b.

It also has solder paste agitators 11a and 11b for agitating the printing members 7a and 7b. Through a passage D provided in the partition wall 13, the printing members 7a and 7b can be mixed. Further, when the printing members 7a and 7b are consumed by printing, the printing members 7a and 7b can be supplied from the printing member supply ports Ra and Rb provided between the partition walls 12 and 13 and the partition walls 13 and 14, respectively. Also, the pressure in the vacuum chambers 1a and 1b can be switched between reduced pressure and atmospheric pressure or higher by switching the connection of the valves 6a and 6b.

By using the vacuum squeegee mechanism 1 of FIG. 1, the printing members 7a and 7b can be satisfactorily printed on the screen 4 or the film surface. Next, the operation will be described. When the vacuum squeegee mechanism 1 comes into contact with the screen 4 or the film surface and moves in the direction of arrow C, the vacuum chamber 1a is connected to a vacuum pump (not shown) by the valve 6a, and the inside of the vacuum chamber 1a and the opening connecting to it are opened. The printing members 7a and 7b are printed while the parts E and F are kept under reduced pressure. Further, the printing members 7a and 7b can print while applying pressure with pistons 9a and 9b. On the other hand, the vacuum chamber 1b is connected to a blower (not shown) by a valve 6b, and it is possible to press the printing members 7a and 7b filled in the openings E and F with compressed air. Although the vacuum chamber 1b is connected to the blower (not shown) by the valve 6b, it may be connected to the atmosphere instead of the blower.

Also, in printing in the direction of arrow B, printing similar to that in the direction of arrow C is possible by changing the decompression and pressurization of the vacuum chambers 1a and 1b. As described above, the vacuum squeegee mechanism 1 continuously performs depressurization, printing, and pressurization, so that the voids in FIG. By pressing the printing members 7a and 7b printed on F with atmospheric air or compressed air, the thixotropic influence of the printing members 7a and 7b is eliminated.

FIG. 2 shows the vacuum squeegee mechanism 21. As shown in FIG. This structure has one space, one cylinder and one piston by removing the partition wall 13 of the vacuum squeegee mechanism 1 shown in FIG. The printing method is the same as that of the vacuum squeegee mechanism 1, and when the traveling direction of the vacuum squeegee 21 moves in the direction of arrow G, the vacuum chamber 1a is connected to a vacuum pump (not shown) by a valve 6a, and the vacuum chamber 1a and this are connected. The printing member 7 is printed while the interiors of the openings E and F connected to are decompressed. Furthermore, the printing member 7 can print while applying pressure with a piston 9 . On the other hand, the vacuum chamber 1b is connected to a blower (not shown) by a valve 6b, and it is possible to press the printing member 7 filled in the openings E and F with compressed air. In the printing in the opposite direction of the arrow G, similar printing is possible by changing the decompression and pressurization of the vacuum chambers 5a and 5b.

Further, the vacuum squeegee 21 shown in FIG. 2 can print while pressing the screen 4 using rollers 16a and 16b instead of the labyrinths 3a and 3b shown in FIG. The rollers 16a and 16b are also well suited for perforated steel screens or screens made of polymeric threads.

3 can be printed while pressing the screen 4 by using boat-shaped blades 17a and 17b instead of the rollers 16a and 16b shown in FIG. It can also cope well with various screens.

FIG. 4 shows a case where only the film 19 is used for printing, and the film 19 is attached to the substrate 18 to form the opening F. The aspect ratio of the opening F (opening depth K/opening It represents a state in which the diameter J) is relatively large. When the printing members 7a and 7b of FIG. 4 are filled, printing with greatly improved voids can be achieved.

FIG. 5 shows a method of exchanging the screen 4 using the recovery plate 22. FIG. FIG. 5A shows the printing in progress. Also, the collection plate 22 is fixed to the screen 4 with a magnet or the like (not shown) as shown.

FIG. 5B shows the state before the replacement of the plate 4 after printing. The vacuum squeegee mechanism 21 is stopped above the collection plate 22 . The filling chambers 32 and 33 of the vacuum squeegee mechanism 21 are filled with the printing members 7a and 7b. Printing members 7a and 7b are attached to the squeegees 8a, 8b and 8c.

In FIG. 5(C), the vacuum squeegee mechanism 21 moves in the direction of the arrow O together with the recovery plate 22 to replace the screen 4 . As shown, the two vacuum chambers 1a, 1b are connected to vacuum pumps. Therefore, the collection plate 22 is pushed by the atmospheric pressure and can move in the direction of the arrow O together with the vacuum squeegee mechanism 21, thereby preventing the printing members 7Aa and 7b from falling.

The printing machine equipped with the vacuum squeegee of the present invention can be used for manufacturing electronic parts such as SMT printing machine, film method bump forming printing machine, resin mold printing machine, mold underfill printing machine for electronic parts, and filling fine gaps. Applied to printing, etc.

Reference Signs List 1 Vacuum squeegee mechanism 2 Vacuum squeegee mechanism 1a Vacuum chamber 1b Vacuum chamber 2a Expansion chamber 2b Expansion chamber 3a Labyrinth seal 3b Labyrinth seal 4 Screen 5a Vacuum chamber wall 5b Vacuum chamber wall 6a Valve 6b Valve 7 Printing member 7a Printing member 7b Printing Member 8a Squeegee 8b Squeegee 8c Squeegee 9a Piston 9b Piston 10a Piston driver 10b Piston driver 11a Solder paste stirring 11b Solder paste stirring Reference Signs List 12 Partition wall 13 Partition wall 14 Partition wall 15 Printing member 16a Roller 16b Roller 17a Boat-shaped blade 17b Boat-shaped blade 18 Substrate 19 film 20a squeegee 20b squeegee 21 vacuum squeegee mechanism 22 collecting plate 23 printing table 24 printing section 25 chamber 26 valve 27 vacuum Pump 28a Vertical drive unit 28b Vertical drive unit 29 Head 30 Horizontal drive unit 31 Printing table lifting unit 32 Filling chamber 33 Filling chamber 34 Filling Chamber A...Gap B...Arrow (direction)
C: Arrow (direction)
D... Passage da... Arrow (direction)
db...Arrow (direction)
E... Opening F... Opening G... Arrow (direction)
J: opening diameter K: opening depth L: air L1: air L2: air M: air N: arrow (direction)
O: Arrow (direction)
P・・・Arrow (direction)
Q: Arrow (direction)
Ra: printing material supply port Rb: printing material supply port

Claims (12)

a printing table on which a substrate to be printed is placed, a squeegee for sliding on the surface of a screen or film in contact with the surface of the substrate to be printed, a driving mechanism for moving the squeegee relative to the printing table; with
In a screen printer that performs printing by filling openings formed in the screen or film with a printing member using the squeegee,
a vacuum wall forming a space that isolates a partial area of the surface of the screen or film from the outside;
a partition wall for partitioning the space formed by the vacuum wall;
a sealing mechanism provided on the end surface of the vacuum wall and in proximity to or in contact with the surface of the screen or film;
the squeegee provided on the end surface of the partition wall and in contact with the surface of the screen or film;
A vacuum squeegee mechanism comprising a vacuum chamber and a filling chamber formed by the vacuum wall and the partition wall,
The filling chamber is filled with the printing member, and the gas in the vacuum chamber is evacuated ,
A plurality of the filling chambers are formed by the partition wall, and a piston capable of applying pressure to the printing member is incorporated in the plurality of the filling chambers,
A screen printing machine , wherein the partition wall between the plurality of filling chambers is formed with a passage through which the printing member can be moved to another filling chamber by the pressure of the piston. The vacuum squeegee mechanism is a driving mechanism capable of moving parallel and perpendicular to the printing table,
Independent vacuum chambers are formed in the vacuum wall on the traveling direction side and the counter-advancing direction side of the parallel motion, and a plurality of vacuum chambers are formed between the advancing direction-side vacuum chamber and the counter-advancing direction side vacuum chamber. The filling chamber is arranged,
A valve is connected to each of the advancing direction side vacuum chamber and the anti -advancing direction side vacuum chamber to switch between an evacuation device and a pressurizing device capable of pressurizing to atmospheric pressure or higher than the atmospheric pressure. The screen printer according to claim 1 The valve is connected to the evacuation device for the vacuum chamber on the traveling direction side, and at the same time, can be connected and switched to the pressurizing device capable of pressurizing the vacuum chamber on the opposite direction side to the atmosphere or higher than the atmospheric pressure. 3. The screen printer according to claim 2, which is a switching valve. 4. The screen printing machine according to any one of claims 1 to 3, wherein each of the plurality of filling chambers has a paste stirrer for stirring the printing member. 5. The screen printing machine according to any one of claims 1 to 4, wherein the plurality of filling chambers has a printing member supply port for replenishing the printing member from the outside. 6. The printing member in the filling chamber is mixed with the printing member in the other filling chamber through the passage formed in the partition wall by the motion of the piston. The screen printer according to any one of the items 7. The screen printing machine according to claim 6, wherein the printing member moved in the passage is stirred by a paste stirrer by changing the pressure in the filling chamber due to the movement of the piston. 8. The screen printer according to any one of claims 1 to 7, wherein the squeegee is made of metal, rubber, resin, or a composite structure thereof. 9. The screen printer according to any one of claims 1 to 8, wherein the seal mechanism is a labyrinth seal. 10. The screen printer according to any one of claims 1 to 9, wherein the sealing mechanism is a roller or a boat-shaped blade. A recovery plate having a flat plate shape for preventing the printing member from falling from the filling chamber when the vacuum squeegee mechanism moves vertically relative to the printing table, and is in proximity to or in contact with the sealing mechanism. The recovery plate is provided above the screen or film , and the recovery plate is adsorbed to the seal mechanism by evacuating the gas in the vacuum chamber, so that the vacuum squeegee mechanism and the recovery plate are together. 2. The screen printing machine according to claim 1, wherein said screen or film can be moved in a vertical direction. a printing table on which a substrate to be printed is placed, a squeegee for sliding on the surface of a screen or film in contact with the surface of the substrate to be printed, a driving mechanism for moving the squeegee relative to the printing table; with
In a screen printer that performs printing by filling openings formed in the screen or film with a printing member using the squeegee,
a vacuum wall forming a space that isolates a partial area of the surface of the screen or film from the outside;
a partition wall for partitioning the space formed by the vacuum wall;
a sealing mechanism provided on the end surface of the vacuum wall and in proximity to or in contact with the surface of the screen or film;
the squeegee provided on the end surface of the partition wall and in contact with the surface of the screen or film;
A vacuum squeegee mechanism comprising a vacuum chamber and a filling chamber formed by the vacuum wall and the partition wall,
The filling chamber is filled with the printing member, and the gas in the vacuum chamber is evacuated or pressurized,
A plurality of the filling chambers are formed by the partition wall, and a piston capable of applying pressure to the printing member is incorporated in the plurality of the filling chambers,
A passage is formed in the partition wall between the plurality of filling chambers so that the printing member can be moved to another filling chamber by the pressure of the piston,
A printing method, wherein printing is performed on the substrate to be printed by moving the vacuum squeegee mechanism parallel to the printing table.