Patent ID: 7015712
Filing Date: 2006-03-21
Classification: G01R

Abstract:
1. A production line environmental stress screening system for an object comprising: a base table having opposing ends including a head expander in a center of said base table; a pair of assembly tables on either side of the head expander; a shaker in the center of the base table, said shaker being positioned below said head expander and connected to the head expander; a fast ramping temperature chamber mounted on a top of the head expander, said chamber including a pair of doors being movable upward and downward on a side of said chamber for insertion and removal of said object with respect to said chamber, said chamber equipped with a liquid nitrogen unit to cool said chamber and heaters to heat the chamber at fast ramp rates; a set of accordion fixture assemblies, said assemblies movable between the assembly tables and the head expander and including a transporting tray, said transporting tray including on a side a fixed end support plate with a plurality of tubular shafts attached thereto, said tubular shafts including a number of support plates mounted thereon and having an end with a movable end support plate, said movable end support plate including a plurality of holes to allow the movement of the support plates on the tubular shafts, and a metal cylinder in a middle of the moveable end support plate to accommodate a shaft collar lock for a pneumatic piston; a collapsing and extending system being located on each end of the base table and including both fixed and movable support plates which support a plurality of extension shafts, said fixed support plate supporting a pneumatic cylinder, the piston of the pneumatic cylinder engages the movable shaft supports of said extending system; wherein said stress screening system allows a relatively large number of objects to be sandwiched between the supporting plates in the accordion fixture assembly whereby while one accordion assembly is pushed into the temperature chamber for high/low temperature and vibration screening, another accordion assembly is moved out from the chamber to the assembly table, said piston then retracts and pulls on the moveable end support plate and the moveable extension shaft and opens the accordion assembly thereby opening the supporting plate and moving said plate onto said tubular shafts and the extension shafts; said objects that have completed an environmental stress screening process are removed and a new set of PCBs are inserted, and the piston pushes the movable support plate and the movable extension shaft support plate to a predetermined location whereby said objects are squeezed together in preparation for environmental stress screening.