Abstract: A dispensing system and method for dispensing material onto a substrate. The dispensing system includes a frame, a support, coupled to the frame, that supports the substrate at a dispensing position in the dispensing system, and a dispensing head, coupled to the frame, that dispenses the material onto the substrate. The dispensing head includes a motor unit having a first motor coupled to an output drive mechanism, and a dispensing unit, removably coupled to the motor unit, having a material outlet from which the dispensing material is dispensed, the dispensing unit having a dispensing mechanism coupled to the material outlet and coupled to the output drive mechanism of the motor unit such that operation of the first motor causes the dispensing mechanism to dispense material through the outlet. The dispensing head may be controlled for deposition of dots of material having diameters smaller than a dispensing needle of the dispensing unit.

Abstract: A method for printing a viscous material on substrates within a stencil printer includes supplying viscous material to a dispensing region of a print head, positioning a first substrate into a print position, printing on the first substrate by means of a pair of blades in contact with a stencil during a first print stroke in which the pair of blades travel in a first direction, the dispensing region being defined between the pair of blades, positioning a second substrate into a print position, and printing on the second substrate during a second print stroke in which the pair of blades travel in a second direction, opposite to the first direction, the pair of blades maintaining contact with the stencil when transitioning between the first and second print strokes. A print head and a stencil printer are further disclosed.

Abstract: The present invention is directed to methods and apparatus for accurately controlling the quantity of material dispensed from dispensing systems. In one aspect of the present invention, a dispensing system includes a calibration system, which collects and measures an amount of material dispensed during a calibration routine. The calibration dispensing pattern and the amount of material dispensed from the dispensing system during the calibration routine are representative of an actual dispensing pattern. The measured amount of material collected during the calibration routine is compared with a target quantity. The dispensing system is adjusted if the difference between the quantity of collected material and the target quantity is greater that a predetermined tolerance.

Abstract: A needle cleaning system, for use with a liquid dispensing system that dispenses a quantity of material through a dispensing needle or transfer pin, includes a vacuuming device coupled with a residual material collection device, wherein the collection device includes at least one appropriately shaped orifice for receiving an end of the dispensing needle or pin. The liquid dispensing system further includes a control system for periodically positioning the dispensing needle or pin relative the orifice in the collection device. The vacuuming device creates an airflow, which passes around the exterior of the needle or pin and into the collection device, thereby removing residual material from the exterior of the dispensing needle or pin without contact.

Abstract: A reflow soldering apparatus and method are provided for reflow soldering electrical and electronic components to circuit boards. The reflow soldering apparatus and method use selective infrared (IR) heating alone or in combination with convection heating to achieve reflow soldering. Selective IR heating provided by the apparatus and method according to the invention helps to eliminate or helps to at least substantially reduce a risk overheating and thermal damage to non-targeted electrical and electronic components and areas of circuit boards during reflow.

Abstract: The invention provides a compact drying chamber for drying printed circuit boards and electronic connectors and components mounted thereto by enhanced evaporation to remove residual water and completely dry printed circuit boards. The compact drying chamber comprises features that help maximize a velocity at which heated air impacts printed circuit boards to significantly enhance evaporation from surfaces of printed circuit boards and to raise the temperature of electronic connectors and components to allow evaporation therefrom, while maintaining low power consumption with respect to heating and circulating air. The compact drying chamber also comprises features that help maximize a dwell time of printed circuit boards in high velocity heated air within practical conveyance speeds, while maintaining overall dimensions that allow a compact design.

Abstract: A two-stage filtration system is coupled with an oven, such as a solder reflow oven, to remove a vapor stream from the oven and to remove organic compounds that have volatilized from a solder flux and other contaminants from the vapor stream. The filtration system includes a first stage for trapping larger particles and a second stage including a packed bed of wettable media, such as steel balls, for trapping smaller particles and serving as a nucleation site for condensed organic compounds. The first stage can be a centrifugal self-cleaning element in the form of a mesh strainer coupled with a rotary motor for spinning the mesh strainer.

Abstract: A liquid dispenser has an augering screw that serves both a metering function and a valving function. The augering screw is axially movable between a position in which fluid can flow and a sealing position in which liquid flow through the nozzle is substantially prevented. The screw is preferably designed with a curved contour between the threads and with a plurality of thread-defining channels to allow liquid to fill more completely around the screw and to dispense more liquid with fewer screw turns than prior screw designs.

Abstract: The invention relates to a method and apparatus for inspecting a substrate having a substance deposited thereon. The steps of the method include depositing the substance onto the substrate; capturing an image of the substrate; detecting variations in texture in the image to determine a location of the substance on the substrate; and comparing the location of the substance with a desired location. The apparatus includes a screen printer that dispenses a substance at a predetermined location on a substrate, and a machine vision inspection system that includes texture based recognition of the substance.

Abstract: An apparatus for processing printed circuit boards including a system for measuring and controlling solder wave height generally comprises conveyor system for transporting printed circuit board through a number of processing stations. The system for measuring and controlling the wave height of solder includes a sensor which is mounted in close proximity to the interface defined between the surface of the solder wave and the bottom surface of the printed circuit board. The sensor is coupled to a micro-controller and the micro-controller is coupled to a pump motor. The pump motor is coupled to a solder bath which generates the solder wave and is controlled to operate at a predetermined speed to maintain a predetermined solder wave height during the process of wave soldering printed circuit boards. The sensor provides a number voltages to the micro-controller representing the distance between the sensor and the top surface of the solder wave. The voltages are converted into a number of values.

Abstract: Flux management systems and methods are provided for filtering vaporized flux from the gas of a reflow soldering oven. A flux management system includes a cooling chamber having a cooling medium through which the gas passes. The vaporized flux condenses on the surfaces of the cooling chamber and drips into a collection pan, thereby preventing it from dripping onto circuit boards passing through the oven. The flux management system may further include a self-cleaning feature that includes a compressed gas, which is allowed to enter the cooling chamber through a solenoid valve. The compressed gas may then be directed through a heater, which increases the temperature of the cooling chamber, thereby causing a decrease in viscosity of the flux, which allows it to flow freely into a drain tube. The flux may then be transported by gravity into a collection container.

Abstract: A rail position control system is provided that controls a conveyor system configuration to accommodate a plurality of differently sized substrates in an apparatus. The rail position control system includes at least one camera, which is mounted on a mounting surface located in close proximity to the conveyor system. The rail position control system further includes a computer system that is operatively coupled to the camera and to a motor. The motor is further coupled to at least one rail of the conveyor system. The camera is operative to view and provide a plurality of images of a conveyor lane width value to the computer system. The conveyor lane width value represents a space located between at least one pair of rails of the conveyor system.

Abstract: The invention provides an apparatus that separates solder from solder dross, comprising first and second rolls and a fixture. The first roll has a substantially cylindrical surface and is rotatable about a first longitudinal axis. The second roll has a substantially cylindrical surface and is rotatable about a second longitudinal axis parallel to the first longitudinal axis. The fixture is coupled to the first and second rolls and spaces the second roll apart from the first roll by a first distance, such as 0.001 to 0.015 inches, the first distance sufficient to separate a solder-dross mixture directed between the first roll and the second roll into a liquid solder and a dross powder when the first and second rolls are rotated in opposite directions.

Abstract: A dual track stencil system includes a first set of rails and a second set of rails, each of the rails being independently controlled for allowing for independent movement of circuit boards through the stencil system for processing. A stencil, having two patterns, each aligned with a respective working area of each track is suspended above the dual track system. In one embodiment, the solder dispensing unit includes a squeegee arm with a solder gathering head. During operation using the squeegee arm with the solder gathering head, two circuit boards are fed to the working area, and both of the circuit boards are serially processed, with excess solder being removed from the board after the processing of each of the boards.

Abstract: The present invention provides a method and apparatus for dispensing onto a substrate. In one embodiment, the apparatus includes an injector having an injecting outlet and an air inlet, a fixture for receiving a substrate in communication with the injecting outlet and the air inlet and having a gasket forming a seal around the injecting outlet and air inlet, and a sheet of substantially taut film disposed between the injector and a substrate placed in the receptacle of the fixture such that, when the injector is in a position for dispensing encapsulant to a process area on the substrate, at least the injectng tip and the inlet tip of the injector project through the substantially taut film to the process area.

Abstract: An apparatus for placing spheres at predetermined positions on a substrate. The apparatus includes a platform to support the substrate at a first sphere placement position in the apparatus, and a placement station disposed above the platform that places spheres at locations on the substrate. The placement station includes a first container having a chamber to contain spheres, and a first carrier tray having a substantially horizontal upper surface that forms a lower surface of the chamber. The upper surface has a first section and a second section, the second section having a plurality of holes formed therein to receive spheres. The first carrier tray is movable to position the second section between a fill position beneath the first container and a place position disposed over the first sphere placement position.

Abstract: An apparatus and method for cleaning excess solder paste that is deposited on a stencil in a stencil printer. The apparatus includes a solvent bath containing a pool of solvent in which a bar is disposed in the solvent bath. The bar rotates in the solvent bath and surface tension between the bar and the solvent causes the solvent to uniformly adhere to the bar. The bar is used to apply solvent to a cleaning material that is used to wipe excess solder paste from the stencil.

Abstract: A printer for printing a viscous material at predetermined positions forming a pattern on a substrate. The printer includes a frame, a device, mounted to the frame, having a number of perforations arranged to form the pattern, a support apparatus, coupled to the frame, that supports the substrate in a printing position beneath the device, and a material dispenser. The material dispenser has a chamber to contain the viscous material to be printed on the substrate. The chamber has an opening through which the viscous material is dispensed. The material dispenser is coupled to the frame, positioned over the device, and constructed and arranged to dispense the viscous material through the perforations in the device and onto the substrate. The material dispenser has a retraction device that prevents leakage of the viscous material from the opening after dispensing is complete.

Abstract: A printer for printing a viscous material at predetermined positions forming a pattern on a substrate. The printer includes a frame, a device, mounted to the frame, having a number of perforations arranged to form the pattern, a support apparatus, coupled to the frame, that supports the substrate in a printing position beneath the device, and a material dispenser. The material dispenser has a chamber to contain the viscous material to be printed on the substrate. The chamber has an opening through which the viscous material is dispensed. The material dispenser is coupled to the frame, positioned over the device, and constructed and arranged to dispense the viscous material through the perforations in the device and onto the substrate. The material dispenser has a retraction device that prevents leakage of the viscous material from the opening after dispensing is complete. The material dispenser includes a temperature control system to maintain the temperature of the viscous material contained in the chamber.

Abstract: An automatic dross removal apparatus, which can be used with a solder wave apparatus, is provided, that generally includes a reservoir having a cavity for containing liquid solder, dross removal apparatus having a first end extending within the cavity of the reservoir for removing dross on the surface of the liquid solder, and a motor engaged with the dross removal apparatus. In one embodiment of the invention, the dross is automatically removed by a conveyor driven by a motor. In another embodiment of the invention, the dross is automatically removed by a motor driven receptacle. Means for moving the dross from one part of the solder reservoir to another, such as a pump, can be included. Preferably, a computer is used to control the automatic dross removal. The dross can be placed in a dross separation device which can include apparatus for processing the dross to remove any remaining solder.