Patent ID: 7981346

Claim:
A method of making hollow micro-projections having side walls and at least one opening in a side wall, comprising providing an essentially cylindrical negative mold defining the exterior shape of said micro-projections; providing an essentially cylindrical positive mold defining the hollow interior shape of said micro-projections; bringing said positive mold into said negative mold, and off-setting the mold halves laterally with respect to each other, such that the distance between an inner wall of the negative mold and the positive mold in said area, ranges from zero to a finite distance which is smaller than the largest distance between the walls of the molds, thereby defining a side opening in an area of a side wall of said negative mold, so as to provide an opening or at least a thinner material thickness in said side wall area compared to the remaining side walls, such that at least one portion of a side wall of said positive mold comes close enough to, and preferably in contact with, at least one portion of said negative mold to define an area corresponding to the desired side opening; molding a desired structure by filling the space between said positive and negative mold with a moldable material; demolding the desired structure from the molds; and s″^ removing any molded material that may be present within the area defining the side opening so as to form said opening.