Why do Can's Domes Reverse?

In can manufacturing, the dome at the bottom of the can is critical for structural integrity. It is initially formed in the Bodymaker, and for thinner gauge material, it may be reformed in the Necker to achieve the final shape.

The dome allows the can to withstand internal pressure, such as that caused by carbonation or thermal expansion. However, if internal pressure rises too high—due to excessive heat or physical impact—the dome may expand or "reverse."

This dome reversal is a built-in safety mechanism. Rather than allowing the can to rupture or explode, the dome inverts outward to relieve pressure. While dome reversal is not ideal, the reversal helps prevent dangerous failures in high-pressure situations.