Claims
- 1. A pressurized injection nozzle for screening paste onto a surface with cavities or blind holes, comprising:
- a nozzle including a pair of nozzle lips cooperating to form a narrow, elongate nozzle slit and sufficiently compliant to move across the surface without damaging the surface as pressure is applied between the nozzle and the surface to contain the paste;
- means for supplying pressurized paste through the slit into the cavities or holes; and
- an exhaust defined by a path, closer to the slit than a width of a cavity or blind hole, for allowing air to escape from cavities or blind holes as they are filled with paste.
- 2. A pressurized injection nozzle as recited in claim 1 wherein said elongate nozzle slit is formed by a thin leading lip and a wide trailing lip, said wide trailing lip acting as a squeegee.
- 3. A pressurized injection nozzle as recited in claim 2 wherein said path defining the exhaust is within said nozzle and is formed by a rigid leading lip and said thin leading lip.
- 4. A pressurized injection nozzle as recited in claim 3 wherein said wide trailing lip is a rigid lip.
- 5. A pressurized injection nozzle as recited in claim 3 wherein said wide trailing lip is a flexible lip.
- 6. A pressurized injection nozzle as recited in claim 1, wherein said means for supplying pressurized paste supplies a paste of solder particles in a flux carrier.
- 7. A pressurized injection nozzle as recited in claim 1, wherein said means for supplying pressurized paste supplies a paste of electrically conductive particles mixed in a thermoplastic and a solvent carrier.
- 8. A pressurized injection nozzle for screening paste onto a surface with cavities or blind holes, comprising:
- a nozzle including a pair of flexible nozzle lips cooperating to form a narrow, elongate nozzle slit and sufficiently compliant to move across the surface without damaging the surface as pressure is applied between the nozzle and the surface to contain the paste; and
- means for supplying pressurized paste through the slit into the holes, said lips parting under pressure between the nozzle and the surface to form the slit and pass paste under pressure to fill the cavities or blind holes, said lips closing to prevent passage of said paste when pressure between the nozzle and the surface is removed.
- 9. A pressurized injection nozzle for screening paste onto a surface with cavities or blind holes, comprising:
- a nozzle including a pair of flexible nozzle lips cooperating to form a narrow, elongate nozzle slit and sufficiently compliant to move across the surface without damaging the surface as pressure is applied between the nozzle and the surface to contain the paste; and
- means for supplying pressurized paste through the slit into the holes, said lips parting under pressure of the pressurized paste to form the slit and pass the paste to fill the cavities or blind holes, said lips closing to prevent passing of the paste when pressure on the paste is removed.
- 10. An apparatus for screening a bonding agent paste onto a surface of a circuit board with cavities or blind holes, comprising:
- a wiping guide adapted to move across the surface without damaging the surface: a blade which cooperates with the wiping guide to form a narrow slit;
- means for supplying a pressurized paste through the slit;
- an exhaust path positioned closer to the slit then a width of the holes; and
- means for moving the nozzle across the surface in a direction perpendicular to the slit.
CROSS REFERENCE TO RELATED APPLICATION
This application is a divisional of application Ser. No. 08/171,898 filed Dec. 21, 1993, U.S. Pat. No. 5,478,700, issued Dec. 26, 1995.
US Referenced Citations (14)
Foreign Referenced Citations (2)
Number |
Date |
Country |
172438 |
Sep 1952 |
AUX |
WO8904728 |
Jun 1989 |
WOX |
Non-Patent Literature Citations (1)
Entry |
D. S. Bendzel et al., "Circular Extrusion Stenciler" IBM Technical Disclosure Bulletin vol. 19, No. 10, Mar. 1976. |
Divisions (1)
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Number |
Date |
Country |
Parent |
171898 |
Dec 1993 |
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