Cube corner sheeting mold and method of making the same

A lamina suitable for use in a mold for use in forming retroreflective cube corner articles, the lamina having opposing first and second major surfaces defining therebetween a first reference plane, the lamina further including a working surface connecting the first and second major surfaces, the working surface defining a second reference plane substantially parallel to the working surface and perpendicular to the first reference plane and a third reference plane perpendicular to the first reference plane and the second reference plane, the lamina comprising:

• a first groove set including at least two parallel adjacent V-shaped grooves in the working surface of the lamina defining a first groove surface and a second groove surface that intersect substantially orthogonally to form a first reference edge;
• a second groove set including at least two parallel adjacent V-shaped grooves in the working surface of the lamina defining a third groove surface and a fourth groove surface that intersect substantially orthogonally to form a second reference edge;
• and
• a third groove set including at least one groove in the working surface of the lamina defining a fifth groove surface and a sixth groove surface, the fifth groove surface intersecting substantially orthogonally with the first and second groove surfaces to form at least one first cube corner element disposed in a first orientation and the sixth groove surface intersecting substantially orthogonally with the third and fourth groove surfaces to form at least one second cube corner element disposed in a second orientation different than the first orientation;
• wherein the at least one first cube corner element comprises a plurality of nonidentical cube corner elements.

A method of manufacturing a lamina for use in a mold suitable for use in forming retroreflective cube corner articles, the lamina having opposing first and second major surfaces defining therebetween a first reference plane, the lamina further including a working surface connecting the first and second major surfaces, the working surface defining a second reference plane substantially parallel to the working surface and perpendicular to the first reference plane and a third reference plane perpendicular to the first reference plane and the second reference plane, comprising:

• forming, with the lamina in a first lamina orientation, a first groove set including at least two parallel adjacent V-shaped grooves in the working surface of the lamina defining a first groove surface and a second groove surface that intersect substantially orthogonally to form a first reference edge;
• forming, with the lamina in a second lamina orientation different than the first lamina orientation, a second groove set including at least two parallel adjacent V-shaped grooves in the working surface of the lamina defining a third groove surface and a fourth groove surface that intersect substantially orthogonally to form a second reference edge;
• and
• forming, with the lamina in a third lamina orientation different from the first and second lamina orientations, a third groove set comprising at least one groove in the working surface of the lamina defining a fifth groove surface and a sixth groove surface, the fifth groove surface intersecting substantially orthogonally with the first and second groove surfaces to form at least one first cube corner element disposed in a first cube orientation and the sixth groove surface intersecting substantially orthogonally with the third and fourth groove surfaces to form at least one second cube corner element disposed in a second cube orientation different than the first cube orientation.

A method of manufacturing a lamina for use in a mold suitable for use in forming retroreflective cube corner articles, the lamina having opposing first and second major surfaces defining therebetween a first reference plane, the lamina further including a working surface connecting the first and second major surfaces, the working surface defining a second reference plane substantially parallel to the working surface and perpendicular to the first reference plane and a third reference plane perpendicular to the first reference plane and the second reference plane, comprising:

• forming a first groove set including at least two parallel adjacent V-shaped grooves in the working surface of the lamina defining a first groove surface and a second groove surface that intersect substantially orthogonally to form a first reference edge;
• forming a second groove set including at least two parallel adjacent V-shaped grooves in the working surface of the lamina defining a third groove surface and a fourth groove surface that intersect substantially orthogonally to form a second reference edge;
• and
• forming a third groove set comprising at least one groove in the working surface of the lamina defining a fifth groove surface and a sixth groove surface, the fifth groove surface intersecting substantially orthogonally with the first and second groove surfaces to form at least one first cube corner element disposed in a first cube orientation and the sixth groove surface intersecting substantially orthogonally with the third and fourth groove surfaces to form at least one second cube corner element disposed in a second cube orientation different than the first cube orientation, the fifth and sixth groove surfaces being formed to define a groove vertex that extends along an axis that intersects the first reference plane at an oblique angle.