Abstract: A computer controlled system for high speed surface mount adhesive placement in circuit board production includes a dot generator supported for motion along the X, Y and Z axes. The dot generator ejects a jet of viscous adhesive that breaks away from the nozzle of the dot generator as a result of its own forward momentum. The system includes an automatic circuit board conveyor with adjustable width and pneumatically operated lift and lock mechanisms. The system runs through a self-diagnostic set-up procedure and dot calibration routine. Dot size and location are monitored through a video camera and vision circuit. A computer interfaces with the vision circuit and with motion, dot generator and conveyor controllers so that the system can operate in a high volume production assembly line. Application programs are executed by the system computer typically utilizing CAD data from a disk or a computer integrated manufacturing (CIM) controller.

Abstract: A disposable nozzle assembly for connection to the lower end of a syringe in a viscous material dispensing apparatus. The disposable nozzle assembly includes a nozzle portion having an internal cylindrical drop generation chamber and an exit orifice. A cylindrical feed tube having a central feed passage has a lower end that can slide up and down within the cylindrical drop generation chamber. A dynamic seal is provided on the lower end of the feed tube that prevents viscous material from escaping between the feed tube and the inner wall of the drop generation chamber. The disposable nozzle assembly is further provided with a modified luerlock fitting having an internal hollow stem that mates with the tapered nozzle of a standard adhesive syringe in a manner which prevents the entrapment of an air bubble in the fluid path when an empty syringe is replaced.

Abstract: A chamber that communicates with a viscous material reservoir has a flexible resilient diaphragm which forms an exterior wall thereof. An impact mechanism, which may comprise a solenoid actuated hammer, applies a predetermined momentum to the diaphragm for rapidly metering a predetermined minute blob of the viscous material from the chamber through a nozzle. The reservoir is pressurized with gas to force the viscous material into the chamber to refill the same. The chamber is heated to control the viscosity of the material. Dispensing rates in excess of four blobs per second can be achieved. Variations in the height of the nozzle from the surface of the workpiece are not critical to uniform rapid dispensing. An alternate embodiment eliminates the diaphragm and instead rapidly retracts a nozzle relative to a fluid feed conduit to eject very small blobs of viscous material. A strain gauge detects refill of the chamber inside the nozzle and sends a signal to control refill logic circuitry.

Abstract: A method is provided for dispensing viscous materials which first requires the step of providing a dispensing device for holding a quantity of a viscous material to be dispensed through a tip thereof. Next, the dispensing device is coupled to a dispensing control so that a metered amount of viscous material will be dispensed in response to a dispensing control signal. Next, the dispensing device is moved along an axis to selectively position the tip a predetermined distance away from the surface of a workpiece positioned adjacent thereto in response to an applied height control signal. The height control signal is generated by processing output signals from a camera which is moved along the axis with the dispensing device to determine when an image of the workpiece surface is maximally in focus.

Abstract: A syringe or other suitable dispensing device is coupled to conventional controls for dispensing viscous material such as adhesives or solder paste through a tip thereof. The syringe is supported on a motor driven carriage for movement along a Z axis in response to height control signals. A camera also mounted on the carriage generates output signals representative of an image of the surface of a workpiece such as a PC board. Circuity processes the output signals from the camera to determine when the image is maximally in focus and generates the height control signals necessary to maintain the tip of the syringe a predetermined constant height above the surface of PC board. This ensures the dispensing of uniform balls of solder paste or adhesive at various locations on the PC board despite warpage in the board.

Abstract: A syringe or any other dispensing device is coupled to a conventional dispensing control unit for dispensing viscous material such as adhesives and solder paste through a hollow needle thereof as metered amounts of pressurized gas are supplied to the syringe in response to a valve control signal applied to the dispensing control unit. The syringe is mounted on an automated frame for independent movement along the X, Y and Z axes in response to drive signals. Predetermined pattern and fluid flow functions are selected for each of a plurality of consecutive movement elements by operator actuation of corresponding discrete manually actuable switches to thereby create a workpiece program which can be automatically executed on command to dispense the viscous material over the upper surface of a workpiece such as a PC board in the prescribed manner.