ADHESIVE APPLYING APPARATUS

Abstract: An adhesive applying apparatus comprises an adhesive applying nozzle (1), an elevation drive device (B) for elevating the adhesive applying nozzle, a preliminarily coating station (6) provided on an upper surface thereof with a tape (5) to be preliminarily coated, a device (10) supporting a circuit board (4), and an XY direction drive device (30) for effecting relative movements of the adhesive applying nozzle to position the nozzle in a predetermined location in a horizontal direction of the circuit board and said tape. The elevation drive device is constructed to enable optionally setting the lowest position of the adhesive applying nozzle, and there is provided control means (D) for giving the elevation drive device a command for setting the lowest position of the adhesive applying nozzle at a predetermined position above the preliminary coating station.

Description: TECHNICAL FIELD The present invention relates to an adhesive applying apparatus for applying an adhesive for fixing an electronic component onto a circuit board as disclosed e.g. in document US-5 505 777. BACKGROUND ART A prior art adhesive applying apparatus will be described with reference to Fig. 6 and Fig. 7. In Fig. 6, a reference character A denotes a perspective view of a prior art adhesive applying apparatus. The reference character B denotes an applying mechanism provided with an applying nozzle 1 for applying an adhesive 3, a syringe 2 for supplying the adhesive 3 to the applying nozzle 1 and a monitor camera 13. The reference character C denotes a purging (discard) station mechanism provided with a purging tape 5 for purging the adhesive 3 and a purging station 6 which is located beside a circuit board conveyance unit 10 and places thereon the purging tape 5 in a purging stage. The aforementioned circuit board conveyance unit 10 and the purging station 6 are supported on an X-Y table 30 and is constructed so as to be able to position the applying nozzle 1 in an X-Y direction. Adhesive applying operation of the purging station to be executed by the prior art adhesive applying apparatus A prior to shipment from the factory will be described next with reference to Fig. 6 and Fig. 7. Conventionally, when shipping an applying apparatus, an operator performs an adjustment for making the height of the upper surface of the purging tape 5 coincide with the height of the upper surface of a circuit board 4 conveyed by the circuit board conveyance unit 10 prior to shipment from the factory. This adjustment is performed by positioning the applying nozzle 1 above the purging station 6, moving down the nozzle to a preset height corresponding to the upper surface of the aforementioned circuit board 4, loosening screws by which the purging station 6 is mounted so that the tip of the applying nozzle 1 is put right in contact with the upper surface of the purging tape 5 on the purging station 6 within a stroke in which the board 4 and the nozzle 1 is put in contact with each other as shown in Fig. 7, thereby vertically adjusting the position of the purging station 6. However, in the aforementioned prior art construction, the height position adjustment of the purging station 6 and the circuit board 4 has required much time. Furthermore, if the height of the upper surface of the purging tape 5 is not coinciding with the height of the upper surface of the circuit board 4 conveyed by the circuit board conveyance unit 10, there occurs the issue that appropriate purging cannot be performed due to the phenomenon that the tip of the applying nozzle 1 is separated from the upper surface of the purging tape 5 or the phenomenon that the tip of the applying nozzle 1 collides against the purging station 6 via the purging tape 5. The present invention has an object to provide an adhesive applying apparatus capable of easily and speedily performing the adjustment of the vertical positional relationship between the upper surface of the circuit board and the upper surface of the purging station in the adjustment stage prior to shipment from the factory or in changing the type of the circuit board. DISCLOSURE OF INVENTION In order to solve the aforementioned issues, the present invention is constructed as follows. According to a first aspect of the present invention, there is provided an adhesive applying apparatus comprising: an adhesive applying nozzle; an elevation drive unit which moves up and down the adhesive applying nozzle and is able to set a lowermost end position of the adhesive applying nozzle; a purging station provided with a purging tape placed on its upper surface; a support unit (10) for supporting a circuit board to be applied with an adhesive from the adhesive applying nozzle; a transverse drive unit which relatively moves the adhesive applying nozzle relative to the circuit board and the purging tape so as to position the nozzle in a specified position in a transverse direction perpendicular to a vertical direction; and a control means for giving the elevation drive unit a command for setting the lowermost end position of the adhesive applying nozzle located in a position above the purging station to a specified position. According to the present invention, the lowermost end position of the applying nozzle can be appropriately set both in the position of the upper surface of the circuit board and in the position of the upper surface of the purging tape placed on the purging station. Therefore, appropriate adhesive applying can be performed even when the upper surface of the circuit board is not coinciding with the upper surface of the purging station. According to a second aspect of the present invention, there is provided an adhesive applying apparatus based on the first aspect, wherein the elevation drive unit moves the adhesive applying nozzle down to the lowermost end position according to a thickness of the circuit board upon receiving a command for setting the lowermost end position of the adhesive applying nozzle to a height of the circuit board from the control means. According to a third aspect of the present invention, there is provided an adhesive applying apparatus based on the first or second aspect, wherein the elevation drive unit is provided with a cam having a curved cam surface, a motor for rotating the cam, a cam follower which moves on the cam surface of the cam, and a shaft which is connected to the nozzle and moves up and down when the cam follower moves on the cam surface of the cam, the motor rotating according to the command from the control means, consequently rotating the cam, moving the cam follower on the cam surface of the cam, moving down the shaft and moving down the adhesive applying nozzle to the set lowermost end position. According to a fourth aspect of the present invention, there is provided an adhesive applying apparatus based on the third aspect, wherein the cam has two cam surfaces of different curvatures so that the lowermost end position of the adhesive applying nozzle is varied when the cam follower is moved on the two cam surfaces by the rotation of the motor. According to a fifth aspect of the present invention, there is provided an adhesive applying apparatus comprising: an adhesive applying nozzle; an elevation drive unit for moving up and down the adhesive applying nozzle; a purging station provided with a purging tape placed on its upper surface; a support unit for supporting a circuit board to be applied with an adhesive from the adhesive applying nozzle; a transverse drive unit which relatively moves the adhesive applying nozzle relative to the circuit board and the purging tape so as to position the nozzle in a specified position in a transverse direction perpendicular to a vertical direction; a station elevation unit which moves up and down the purging station; and a control means for giving the station elevation unit a command for setting a height of the purging station to a specified height. According to the present invention, the height position of the purging station can be easily speedily adjusted when a displacement occurs between the position of the upper surface of the circuit board and the position of the upper surface of the purging tape placed on the purging station. Therefore, appropriate purging can be performed. According to a sixth aspect of the present invention, there is provided an adhesive applying apparatus based on the fifth aspect, wherein the station elevation unit moves up and down the purging station according to a thickness of the circuit board upon receiving the command for setting the height of the purging station to the height of the circuit board from the control means. According to a seventh aspect of the present invention, there is provided an adhesive applying apparatus based on any of the fourth through sixth aspects, wherein the station elevation unit is provided with a motor and a threaded shaft which is driven by the motor to move up and down the purging station. According to an eighth aspect of the present invention, there is provided an adhesive applying apparatus based on any of the first through seventh aspects, wherein the circuit board is supported by being positioned by the support unit with its lower surface served as a reference, and the height of the upper surface of the circuit board is changed every time the thickness of the circuit board is varied. BRIEF DESCRIPTION OF DRAWINGS These and other objects and features of the present invention will be apparent from the following description in conjunction with the preferred embodiments thereof with reference to the accompanying drawings, in which: Figs. 1A, 1B and 1C are perspective views of the whole body and essential parts of an adhesive applying apparatus according to a first embodiment of the present invention; Fig. 2 is a view showing the operation of the above adhesive applying apparatus; Fig. 3 is a view showing the operation of the above adhesive applying apparatus; Fig. 4 is a schematic view showing an elevation drive unit of an adhesive applying nozzle of the above adhesive applying apparatus; Fig. 5 is a side view showing the construction of a purging station of an adhesive applying apparatus according to a second embodiment of the present invention; Fig. 6 is a perspective view of the whole body and essential parts of a prior art adhesive applying apparatus; Fig. 7 is a side view showing the construction of a purging station of the prior art adhesive applying apparatus; and Fig. 8 is a perspective view of a purging station mechanism of an adhesive applying apparatus according to a third embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Before continuing the description of the present invention, it is to be noted that the same components are denoted by the same reference numerals in the accompanying drawings. An adhesive applying apparatus according to a first embodiment of the present invention will be described with reference to Fig. 1A through Fig. 5. In Figs. 1A, 1B and 1C, the reference character A denotes a perspective view of the adhesive applying apparatus of the first embodiment. The reference character B denotes an applying mechanism provided with a plurality of applying nozzles 1 for applying an adhesive 3, a plurality of syringes 2 for supplying the adhesive 3 to the plurality of applying nozzles 1, and a monitor camera 13. The reference character C denotes a purging (discard) station mechanism provided with a purging tape 5 which purges the adhesive 3 while being rewound from a reel 200 and wound around a reel 201, a purging station 6 which is located beside a circuit board conveyance unit 10 of an example of a circuit board support unit and on which the purging tape 5 is placed in a purging stage, a ball thread shaft 7 which rotates to vertically move the purging station 6 to thereby position the station in the vertical direction (Z direction), and a vertical movement motor 8 for rotating the ball thread shaft 7. The aforementioned circuit board conveyance unit 10 and purging station 6 are supported on an X-Y table 30 of an example of a transverse drive unit for moving the applying nozzle 1 in a transverse direction, e.g., X-Y direction perpendicular to the vertical direction and are constructed so that they can be positioned in a horizontal direction (X-Y direction) relative to the applying nozzle 1. Fig. 4 shows the construction of an elevation drive unit 100 for moving up and down the applying nozzle 1. The applying nozzle 1 and the syringe 2 are supported by a stroke shaft 14, the stroke shaft 14 is supported by a support fulcrum 15, and an arm 16 is pivotally supported by the support fulcrum 15. The arm 16 is pivotally supported at a fulcrum 20, and its end portion on the other side is urged by a spring 19. A cam follower 17 is provided halfway between the aforementioned support fulcrum 15 of the arm 16 and the aforementioned fulcrum 20, and a cam 18 is put in contact with the lower side of the cam follower 17. This cam 18 is driven by a motor 21 which rotates forwardly and reversely, and the motor 21 is controlled by a control section D. In this construction, the top dead center position and the bottom dead center position of the adhesive applying nozzle 1 are determined by a position of the cam 18 indicated by  1 and a position of the cam 18 indicated by  2 . Then, by forwardly and reversely rotating the cam 18 within a range of  1 to  2 , the lowermost end position of the applying nozzle 1 is determined. By arbitrarily determining the  1 and  2 , the aforementioned lowermost end position can be adjusted. The control section D instructs the motor 21 about the aforementioned reciprocation pivot angle range of  1 to  2 . Further, in regard to this cam 18, it is acceptable to provide a reciprocation pivot angle range of  1 to  3 having a curvature different from the aforementioned reciprocation pivot angle range of  1 to  2 to allow the adhesive applying nozzle 1 to be moved up and down with an amount of stroke greater than or smaller than the aforementioned reciprocation pivot angle range of  1 to  2 , thereby allowing the lowermost end position of the applying nozzle 1 to be adjusted in a wider range. Fig. 5 shows the details of the purging station mechanism C. By forwardly and reversely rotating the ball thread shaft 7 mounted on the rotary shaft of the vertical movement motor 8, the purging station 6 meshed with the ball thread shaft 7 is moved in the vertical direction, when vertical guides 9 and 9a guide the purging station 6 in the vertical direction. The reference character D denotes a control section which controls the whole body of the adhesive applying apparatus A and includes an X-Y direction positioning mechanism for positioning an applying point of the circuit board 4 and positioning the purging station 6 in the X-Y direction by positioning the X-Y table 30, an applying control mechanism for moving and positioning the applying nozzle 1 of the applying mechanism B in the Z direction and a purging station control mechanism for moving and positioning the purging station 6 in the vertical direction by controlling the vertical movement motor 8. The reference character E denotes a display section which displays a control condition of the aforementioned applying control mechanism and a control condition of the aforementioned purging station control mechanism. An adhesive applying operation in changing the type of the circuit board in the adhesive applying apparatus of the first embodiment will be described next with reference to Fig. 1A through Fig. 3. In Figs. 1A, 1B and 1C, when changing the type of the circuit board 4, the viscosity and so forth of the adhesive inside the applying nozzle 1 are changed due to suspension of the applying operation. Therefore, it is required to stabilize the adhesive applying by consuming the adhesive at the viscosity changed portion by purging and confirm that a state in which appropriate applying is performed, by means of the monitor camera 13 before starting the applying work on the circuit board 4. The purging operation of the first embodiment will be described with reference to Fig. 2. In Fig. 2, the control section D sets the aforementioned  1 and  2 so that a vertical stroke S 1 of the applying nozzle 1 is adjusted to the lowermost end position coinciding with the position of the upper surface of the circuit board 4 conveyed by the circuit board conveyance unit 10. In this stage, when the position of the upper surface of the purging tape 5 placed on the purging station 6 is coinciding with the position of the upper surface of the aforementioned circuit board 4, the purging can be performed without doing anything else. However, when the position of the upper surface of the purging tape 5 placed on the purging station 6 is not coinciding with the position of the upper surface of the aforementioned circuit board 4, there are the issue that the tip of a positioning projection 1b of the applying nozzle 1 does not reach the upper surface of the purging tape 5 consequently causing abnormal applying position, size and shape of the adhesive discharged from a nozzle opening 1a and the issue that the tip of the positioning projection 1b of the applying nozzle 1 collides against the purging station 6 via the purging tape 5. In the first embodiment, the control section D changes the aforementioned stroke S 1 according to the height position of the purging tape 5 placed on the purging station 6 so as to make it a purging stroke S 2 , so that the tip of the positioning projection 1b of the applying nozzle 1 just coincides with the upper surface of a purging tape 5a. With the above arrangement, the applying nozzle 1 is moved down by the stroke S 2 , so that the tip of the positioning projection 1b of the applying nozzle 1 reaches the upper surface of the purging tape 5b, thereby performing the appropriate purging. When the purging is completed, the vertical stroke S 2 of the applying nozzle 1 set by the control section D is set back to the vertical stroke S 1 , and then adhesive applying on the circuit board 4 is performed. This arrangement obviates the need, as in the prior art, for the troublesome work of making the position of the upper surface of the purging tape 5 coincide with the position of the upper surface of the circuit board 4 by loosening the screws for fixing use and allows the work for changing the circuit board 4 for a new type to be easily and speedily performed. The purging operation of the second embodiment of the present invention will be described next with reference to Fig. 3. In Fig. 3, the vertical stroke S 1 of the applying nozzle 1 set by the control section D has a stroke length appropriate for the purging when the position of the upper surface of the circuit board 4 is coinciding with the position of the upper surface of the purging tape 5 placed on the purging station 6. Therefore, if the position of the upper surface of the purging tape 5 is lower than the position of the upper surface of the circuit board 4 as indicated by the dashed lines in Fig. 3, there is the issue that the tip of the positioning projection 1b of the applying nozzle 1 does not reach the upper surface of the purging tape 5 with the aforementioned vertical stroke S 1 kept intact, consequently causing abnormal applying position, size and shape of the adhesive discharged from the nozzle opening 1a. In the second embodiment, the vertical stroke S 1 of the applying nozzle 1 set by the control section D is kept intact, and a purging station control condition of the control section D is changed from a positioning condition H 1 in which the position of the upper surface of the purging tape 5 is lower than the position of the upper surface of the circuit board 4 into a positioning condition H 2 in which the position of the upper surface of the purging tape 5 coincides with the position of the upper surface of the circuit board 4, and the vertical movement motor 8 shown in Fig. 4 is rotated to rotate the ball thread shaft 7, thereby vertically moving the purging station 6 meshed with the ball thread shaft 7 and making the position of the upper surface of the purging tape 5 coincide with the position of the upper surface of the circuit board 4. With this arrangement, the appropriate purging can be performed with the vertical stroke S 1 set by the control section D kept intact. As shown in Fig. 8, an adhesive applying apparatus according to a third embodiment which is not part of the present invention is provided with an operating knob 12 in place of the vertical movement motor 8 of the second embodiment, and it is also possible to rotate a ball thread shaft 11 by forwardly and reversely rotating the operating knob 12, thereby vertically moving the purging station 6 for the positioning of it in the vertical direction. The aforementioned embodiments can be applied to the following cases other than the case where height adjustment between the upper surface of a circuit board to be a reference and the upper surface of the purging tape 5 is performed prior to shipment from the factory. That is, in a case where the circuit board 4 is changed to one having a varied thickness according to the change of the type of the circuit board 4 and the circuit board 4 is supported by the circuit board conveyance unit 10 with the lower surface of the board 4 served as a reference, the height of the upper surface of the circuit board 4 differs from the height of the upper surface of the purging tape 5. In such a case, the adjustment of the lowermost end position of the aforementioned applying nozzle 1 or the adjustment of the position of the upper surface of the purging tape 5 of the purging station 6 according to the aforementioned embodiment can be performed. The aforementioned adhesive applying apparatus is constructed so that the elevation drive unit of the adhesive applying nozzle can arbitrarily set the lowermost end position of the adhesive applying nozzle and includes the control means for giving the aforementioned elevation drive unit a command for setting the lowermost end position of the adhesive applying nozzle located in a position above the purging station to a specified position. With this arrangement, the appropriate purging can be performed by easily and speedily adjusting the lowermost end position of the applying nozzle so as to make it appropriate for the purging even when a displacement occurs in the height position between the upper surface of the circuit board and the upper surface of the purging station when the type of the circuit board is changed, so that an effect of improving the productivity can be obtained. Furthermore, the aforementioned adhesive applying apparatus has the station elevation unit for moving up and down the purging station and the control means for giving the aforementioned station elevation unit the command for setting the height of the purging station to the specified height. With this arrangement, the appropriate purging can be performed by easily and speedily adjusting the height position of the purging station so as to make it appropriate for the purging even when a displacement occurs in the height position between the upper surface of the circuit board and the upper surface of the purging station when the type of the circuit board is changed, so that an effect of improving the productivity can be obtained. Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.

Claims: An adhesive applying apparatus comprising: an adhesive applying nozzle (1); an elevation drive unit (100) which moves up and down said adhesive applying nozzle and is able to set a lowermost end position of said adhesive applying nozzle; a purging station (6) provided with a purging tape (5) placed on its upper surface; a transverse drive unit (30) which relatively moves said adhesive applying nozzle relative to said circuit board and said purging tape so as to position the nozzle in a specified position in a transverse direction perpendicular to a vertical direction; characterised in a support unit (10) for supporting a circuit board (4) to be applied with an adhesive from said adhesive applying nozzle; and a control means (D) for giving said elevation drive unit a command for setting the lowermost end position of said adhesive applying nozzle located in a position above said purging station to a specified position. An adhesive applying apparatus as claimed in Claim 1, wherein said elevation drive unit (100) moves the adhesive applying nozzle down to the lowermost end position according to a thickness of said circuit board upon receiving a command for setting the lowermost end position of said adhesive applying nozzle to a height of said circuit board from said control means. An adhesive applying apparatus as claimed in Claims 1 or 2, wherein said elevation drive unit (100) is provided with a cam (18) having a curved cam surface, a motor (21) for rotating the cam, a cam follower (17) which moves on the cam surface of said cam, and a shaft (14) which is connected to said adhesive applying nozzle and moves up and down when said cam follower moves on the cam surface of said cam, said motor rotating according to said command from said control means, consequently rotating said cam, moving said cam follower on the cam surface of said cam, moving down said shaft and moving down said adhesive applying nozzle to said set lowermost end position. An adhesive applying apparatus as claimed in Claim 3, wherein said cam has two cam surfaces of different curvatures so that the lowermost end position of said adhesive applying nozzle is varied when said cam follower is moved on the two cam surfaces by rotation of said motor. An adhesive applying apparatus comprising: an adhesive applying nozzle (1); an elevation drive unit (100) for moving up and down said adhesive applying nozzle; a support unit (10) for supporting a circuit board (4) to be applied with an adhesive from said adhesive applying nozzle; a transverse drive unit (30) which relatively moves said adhesive applying nozzle relative to said circuit board and said purging tape so as to position the nozzle in a specified position in a transverse direction perpendicular to a vertical direction; characterised in a purging station (6) provided with a purging tape (5) placed on its upper surface; a station elevation unit (C) which moves up and down said purging station; and a control means (D) for giving said station elevation unit a command for setting a height of said purging station to a specified height. An adhesive applying apparatus as claimed in Claim 5, wherein said station elevation unit (C) moves up and down said purging station according to a thickness of said circuit board upon receiving the command for setting the height of said purging station to a height of said circuit board from said control means. An adhesive applying apparatus as claimed in any of Claims 4 through 6, wherein said station elevation unit (C) is provided with a motor (8) and a threaded shaft (7) which is rotated by said motor to move up and down said purging station. An adhesive applying apparatus as claimed in any of Claims 1 through 7, wherein said circuit board is supported by being positioned by said support unit with its lower surface served as a reference, and a height of the upper surface of said circuit board is changed every time a thickness of said circuit board is varied.

Inventors: KAKISHIMA NOBUYUKI, MIBUCHI TAKAYUKI, NAKAHIRA HITOSHI, WACHI AKIHIKO, KAKISHIMA, NOBUYUKI, MIBUCHI, TAKAYUKI, NAKAHIRA, HITOSHI, WACHI, AKIHIKO
Applicants: MATSUSHITA ELECTRIC IND CO LTD, MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Application year: 1997
Main classification: B05C11
IPC codes: B05C11, H05K13, B05C5, B05B15