Abstract: A system is provided for depositing an extremely small amount of solder on a printed circuit board by varying the direction of an electric current applied to a solder stream. The force exerted on the solder can be substantially instantaneously reversed without the necessity of changing the form of the energy applied to the solder from electrical to vibratory, ultrasonic, magnetic, or the like. The direction and magnitude of the force is related to the cross product of an electric current vector and a magnetic field vector (F=I.times.B). A programmable current source is used to place an electric current through the liquid solder as it is flowing through a conduit. A magnetic coil is disposed adjacent the conduit in order to provide a magnetic field in the same plane as the electric current. The conduit supplies liquid solder to a nozzle which then deposits a droplet of solder onto a printed circuit board.

Abstract: A system is provided for determining the presence, or absence of a component on the end of a vacuum pickup device. A monitor having a transparent body portion and plural air flow passageways is provided. An indicator is provided for each vacuum pickup device and contained within the air flow passageway intermediate a vacuum source and the vacuum pickup device. The position of the indicators within the flow passage is dependent upon the presence, or absence of a component on the end of the vacuum pickup device. With a component present on the pickup device, air flow through the passageway, due to the application of the vacuum source, is minimal and the indicator will be biased in a first direction. However, when a component is absent the pickup device, substantial air flow occurs through the passageway, thereby biasing the indicator in a second direction.

Abstract: A placement head assembly for use in an electrical component placement machine. A hollow main shaft has a carriage assembly disposed thereabouts with rollers providing axial movement along the shaft. A vacuum support shaft within the main shaft telescopes downwards to pickup and retain a component. The carriage assembly carries actuator means urging it into axial movement in response to fluid pressure differentials. Tweezer means are pendantly disposed in quadrature from pivot points about the shaft. Pivoting action of the tweezer means forces jaws radially inwards into contact with the component, thereby aligning it for subsequent board placement. In one embodiment, the actuator means includes a piston-cylinder assembly. Pressure differential across the piston causes downward movement of the carriage assembly. Reverse pressure differential urges the carriage assembly upward.