Advanced Mounting System and Method: To Establish and Maintain Predictable and Accurate Grind Plane Reference for Solder Joint Cross-section Processing

摘要

Today's smaller structures, increasing standards and automation, amplify the demand for accurate and reliable cross-section mounting and grinding processes. Presented here is an advanced solution directly addressing these problems by holding components aligned during the encapsulation and grinding processes with greater accuracy, stability and robustness. This advanced system is composed of 3 elements, #1 hand operated, finger adjustable, component fixturing devices that grasps surface mounted components by the machined package surfaces, and maintains them in a precise attitude perpendicular to the fixture's base plate irrespective of the attached printed circuit board sample, #2 precision machined molds, #3 a precision machined grinding fixture with sample holes sized to restrict excessive movement that could result in grinding errors. This system is state of the art in that there are currently no known methods to accurately fix circuit board components in epoxy based sample pots. Existing methods deploy consumable clips or pins to support target components during epoxy pouring. Clips do not prevent component shifting or movement during epoxy pouring or air evacuation. Clips often fail to provide repeatable straight and parallel samples for cross-sectioning, because they attach low on the component, and are prone to movement via disruption, and weight balance of the component being encapsulated. The author has witnessed results ranging from reasonably straight to completely unacceptable forty degree tilting. The Planar Grind Fixture insures consistent component attitude during the potting process.