Method and apparatus for cleaning passageways in metal castings

A method of cleaning a plurality of metal castings, each casting having multiple passageways extending through the casting and opening at different surface portions of the casting, comprising:

• rotating the plurality of castings along a circular path around a horizontal axis so that the passageways open downwardly for a sufficient period of time during which rotation occurs to enable sand and casting debris to drop from the passageways;
• vibrating at least one of the castings for a period of time sufficient to loosen the debris said vibration produced by interrupting the rotation of the casting so that the casting is stationary, while the casting is vibrated to provide a cycle of alternating periods of vibration and periods of non-vibration;
• simultaneously introducing a high pressure burst of air into the openings of the passageways of at least one of the castings at one of the casting surface portions for a sufficient period of time to blow out sand and other casting debris, said time duration that is measured in milliseconds during at least one of the period of non vibration while rotating along the circular path;
• whereby the alternating vibration and high pressure air bursts loosen and blow out of the passageways sand and any other casting debris containing therein, and the force of gravity causes loose sand and other casting debris to drop from the passageways during periods within the time that they are rotated when they open downwardly.