Solder paste is a dense suspension (volume fraction of about 50%)of spherical solder alloy particles in a flux/vehicle system. It isknown to exhibit viscoelastic properties and under oscillatory shear,the dynamic viscosity has been shown to decrease as the shear frequencyincreases. This paper presents experimental results of the effect ofsinusoidal vibration on solder paste, and its impact on the performanceof the paste printing process. In the first experiment, the solder pastesample was horizontally vibrated inside a cylindrical container.Observations of the sample following vibration showed that a thin liquidrich layer was formed on the surface and at the interface between thecontainer and the paste. In the second experiment the sample was placedon a flat plate and as the plate moved towards a vibration squeegee, thesample was pushed by the squeegee blade to produce a paste roll. In bothexperiments, the vibration frequency and amplitude were varied toobserve their effect
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