Micro-vibration compaction sand molding machines use the same high frequency low amplitude vibration for the mold plates, sand boxes, and molds during the compaction process. As the sand box compacts, the molding sand fills to lose suspension, creating numerous voids between sand particles. Direct mold plate vibration energizes the sand particles, which causes them to shift to and find new equilibrium positions to fill the voids for better compaction. Continuing to apply vibration during the compaction process accomplishes this, and also reduces the external friction between the sand particles and the walls of the sand box to improve the compaction further. This means that the additional vibration is crucial to improving the uneven compaction during the compaction process.
When combined with micro-vibration, traditional compaction techniques achieve even higher average compaction densities than compaction alone. Micro-vibration enhances the movement of sand during compaction, resulting in average compaction densities that are higher and more consistent distribution of density even at the same compaction pressure. Micro-vibration sand compaction sand molding machines not only do micro-vibration during compaction, they also do it during sand charging, referred to as pre-vibration before compaction. This method amplifies the volume of sand that is charged in the flask, improves the density and uniformity of the initial sand mold compaction, reduces the pre-charge box height, and decreases the stroke of the compaction piston. This is especially beneficial when molding complex patterns or tall flasks.