Capillary test specimen, system, and methods for in-situ visualization of capillary flow and fillet formation

• Main Authors: Hall, Aaron C, Hosking, F. Michael, Reece, Mark
• Format: Patent
• Language: English
• Published: 24.06.2003

The present invention relates generally to test specimens and methods for evaluating the behavior of a liquid flowing in a capillary channel driven by capillary forces. In particular, the present invention relates to a capillary test specimen, method, and system for in-situ visualizing and quantifying the flow of liquid polymers or molten solders or braze alloys or similar filer materials in capillary channels and gaps, including the formation of fillets at two free surfaces that have been configured to represent realistic joint geometries. A capillary test specimen, method, and system for visualizing and quantifying capillary flow of liquids under realistic conditions, including polymer underfilling, injection molding, soldering, brazing, and casting. The capillary test specimen simulates complex joint geometries and has an open cross-section to permit easy visual access from the side. A high-speed, high-magnification camera system records the location and shape of the moving liquid front in real-time, in-situ as it flows out of a source cavity, through an open capillary channel between two surfaces having a controlled capillary gap, and into an open fillet cavity, where it subsequently forms a fillet on free surfaces that have been configured to simulate realistic joint geometries. Electric resistance heating rapidly heats the test specimen, without using a furnace. Image-processing software analyzes the recorded images and calculates the velocity of the moving liquid front, fillet contact angles, and shape of the fillet's meniscus, among other parameters.