on it is understood that cuts of pieces on the edge of the plate will only partially define the shape of the piece the plate edge will define the remainder of the piece the depth of the cut must be sufficient to allow easy separation of the piece from the plate additionally the cut must be made in a manner to maintain structural integrity of the whole plate during cleaning and processing subsequent to the laser cutting moreover the partial cut depth should be effective to allow separation without damage to the piece which would cause rejection of the final product in one embodiment the cut is made to a depth of about two thirds of the overall thickness of the plate fig3 and 4 illustrate a laser cut of about two thirds of the overall thickness in one embodiment the cut is made to a depth effective to result in a surface roughness ra of the uncut cleaved portion of the plate upon cleavage of less than or about equal to 5 u03bcm ra is the arithmetic average of the absolute distances of all profile points from the mean line the mean line is normally the line of the ideal surface the piece is separated by application of pressure to the plate along the cut in one embodiment the pressure is applied to the bottom of the plate the separation step may be performed manually but more preferably.