Pat. No. 4,912,980

The patented ‘Stacker’ Circuit Board Fixture provides the electronics industry a unique way to test virtually any circuit board. The MPF series fixture is a totally mechanical system that eliminates the added costs of maintenance associated with hydraulic or pneumatic systems. Unlike a hydraulically operated fixture, the Stacker allows total custom tailoring in the test lab to adjust to varying sized and quantities of circuit boards.

Each mounting layer has a ½ grid of ¼-20 threaded holes for mounting of Delrin (included) or Aluminum clamping strips. The clamping strips fit virtually any circuit board. For applications where clamping of the circuit boards is not allowed, special circuit board interface hardware is available.

Since all Stacker components are interchangeable, each fixture assembly can expand to fit all future testing and budget needs. The modular design permits the flow of individual components to various test stations to meet varying production requirements. The individual mounting layers can be used for handling, storage, and transporting of the circuit boards to various test stations without the additional contact with the test items.

The assembly of seven or more mounting layers forms a “cube” which can be rotated to achieve three mutually perpendicular test axes. Cable access is provided for each mounting layer as well as finger slots for lifting and handling. Optional spacer layers are available, which provide an additional 1.50″ of clearance between the layers for circuit boards with large IC components. The spacer layers also incorporate large holes around the perimeter to provide air circulation in thermal environments.

Also available is a specially designed “Stacker Head Expander” (HE/MPF) to interface the Stacker to small shaker armatures. The HE/MPF incorporates perimeter clamping bars and heavy duty threaded inserts to allow testing of larger components using straps and clamping bars. The same tapped grid pattern that exists on each Stacker mounting layer, also exists on the top surface of the HE/MPF. Typically test applications have included shipping containers and lightweight electronic components.

The Mini-Stacker Test Fixture is a universal fixture designed to hold multiple IC’s or other small components in a layered format similar to our larger MPF Stacker Fixture. The multiple test items are ‘sandwiched’ between pocketed layers of frangible foam material. The foam layers replace the traditional beeswax to hold tiny components, therby eliminating contamination.

The Mini-Stacker, when all layers are assembled, forms a cube that can be rotated to any 90° angle to achieve 3 axes of vibration or 6 axes of shock testing without further contact with the test components. Access is provided to the foam cavities for accelerometer or electrical connector cables.

The Mini-Stacker is supplied complete with an adapter plate that mounts directly to a shaker armature or to a horizontal slip plate. Foam inserts and all necessary hardware for assembly is provided with the Mini-Stacker.