Green sheet support fixture speed and position control system for a

Abstract

A horizontally movable slide bears a two section, continuously extending horizontally inclined, steep and shallow sloped cam slot controlling the vertical rise and fall of a cam follower driven support fixture for supporting a ceramic green sheet in underlying contact with a stencil mask in an automatic MLC screening machine. An apertured positioning flag moves horizontally with the slide and past a vertical height digital position encoder assembly and a mask separate encoder assembly. The positioning encoder assembly provides an electrical signal for controlling an actuator mechanism causing slide movement, indicative of the desired final positioning height of the green sheet relative to the mask when the fixture is moving towards the mask. When the actuator mechanism drives the slide in the opposite direction, to lower the green sheet from the mask, the mask separate encoder assembly produces a signal, in response to common positioning flag movement in the opposite direction with the slide to effect a change in speed of the actuator mechanism. This provides slow initial separation of the green sheet from the mask and final removal of the fixture from screening height, at a much more rapid rate.