Abstract: Methods and apparatus for applying molten solder are disclosed. A system for applying solder to a workpiece includes a conveyor for moving a first workpiece along a machine direction, and a first selective soldering nozzle to apply solder to the first workpiece while the first workpiece is moving along the machine direction. The system can also include a flux application area to apply flux to bottoms of workpieces, a heating area to heat the bottoms of the workpieces, and a conveyor to convey the workpieces. The workpiece can constantly move through multiple areas, such as a flux application area, a heating area, and a selective soldering area. As such, two or more areas can operate on the workpiece simultaneously and while the workpiece is moving. The method includes applying solder from the first selective soldering nozzle to the first workpiece while the first workpiece is moving along the machine direction.

Abstract: A system for dispensing a viscous material onto a substrate which includes a dispensing element, a viscous material reservoir and a metering device coupled between the reservoir and the dispensing element for metering a variable amount of a viscous material through the dispensing element. The dispensing element and metering device can be moved by a positioner along a predetermined pattern adjacent a surface of a substrate. A weigh scale located adjacent the substrate receives a metered amount of the viscous material and produces signals representative of a variable weight of the material dispensed during a predetermined time interval. A controller adjusts a speed of movement of the positioner along the predetermined pattern to cause the dispensing element to dispense a desired amount of material based on a calculated flow rate.

Abstract: A system for dispensing a viscous material onto a substrate which includes a dispensing element, a viscous material reservoir and a metering device coupled between the reservoir and the dispensing element for metering a variable amount of a viscous material through the dispensing element. The dispensing element and metering device can be moved by a positioner along a predetermined pattern adjacent a surface of a substrate. A weigh scale located adjacent the substrate receives a metered amount of the viscous material and produces signals representative of a variable weight of the material dispensed during a predetermined time interval. A controller adjusts a speed of movement of the positioner along the predetermined pattern to cause the dispensing element to dispense a desired amount of material based on a calculated flow rate.

Abstract: A system for dispensing a viscous material onto a substrate which includes a dispensing element, a viscous material reservoir and a metering device coupled between the reservoir and the dispensing element for metering a variable amount of a viscous material through the dispensing element. The dispensing element and metering device can be moved by a positioner along a predetermined pattern adjacent a surface of a substrate. A weigh scale located adjacent the substrate receives a metered amount of the viscous material and produces signals representative of a variable weight of the material dispensed during a predetermined time interval. A controller adjusts a speed of movement of the positioner along the predetermined pattern to cause the dispensing element to dispense a desired amount of material based on a calculated flow rate.

Abstract: An anti-float plunger for a pneumatically actuated syringe includes an inner cylindrical ring with two open ends held within a cylindrical cover having one open end and one closed end. The open end is at the backside of the plunger. The closed end is at the frontside, in contact with liquid to be forced through the syringe outlet. The cover includes an outer flexible wiper extending around the circumference. This wiper maintains an airtight seal with the syringe walls even when the walls bulge outwardly due to excessive backside pressure. The cover also includes a deformable membrane at the closed end, which deforms away from the outlet to alleviate residual pressure buildup on the liquid in the frontside. This structure eliminates air entrapment within the syringe, while also preventing residual pressure buildup within the syringe.

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 system for dispensing a viscous material onto a substrate which includes a dispensing element, a viscous material reservoir and a metering device coupled between the reservoir and the dispensing element for metering a variable amount of a viscous material through the dispensing element. The dispensing element and metering device can be moved by a positioner along a predetermined pattern adjacent a surface of a substrate. A weigh scale located adjacent the substrate receives a metered amount of the viscous material and produces signals representative of a variable weight of the material dispensed during a predetermined time interval. A controller adjusts a speed of movement of the positioner along the predetermined pattern to cause the dispensing element to dispense a desired amount of material based on a calculated flow rate.

Abstract: A computer controlled method for high speed viscous fluid dispensing includes the steps of providing a dot generator and moving the dot generator along at least X and Y axes. The dot generator is controlled to repeatedly eject jets of viscous fluid that break away from the dot generator as a result of their forward momentum and fly to the surface of an adjacent substrate to create dots. The method may further comprise the step of monitoring the size and location of the dots through a vision system. The method may further comprise the steps of assigning dot sizes to specific components based on user specifications or a component library. The method may further comprise the step of optimizing the dot placement paths by aligning the in-line points of dot formation.

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.