Three-dimensional tread sipes and mold blade for forming three-dimensional tread sipes

Both a mold blade (10) for forming sipes and the sipe (20) so formed in a tire tread element (32', 32") have three-dimensional portions. In the formed sipe (20), the three-dimensional portion creates a constant interlocking of the opposing sipe faces. The blade (10) and the sipe (20) have two radially adjacent rows (22, 24) of projections (14), wherein the projections (14) are separated by a planar section (26, 30), the planar section (26, 30) having a defined length and width.