Method for Machining Optical Workpieces, in Particular Spectacle Lenses Made of Plastic

A method of machining optical workpieces, in which a semi-finished product (HZ) with predetermined surface geometries at a front side (FS) and a rear side (RS) remote therefrom and with a contoured edge (RA) of predetermined edge thickness (D2) between the front side (FS) and the rear side (RS) is formed starting from a blank (RL), comprising the following principal steps executed in the stated sequence:

• i) providing the blank (RL), which has a blank thickness (D1) and can already have the predetermined surface geometry at the front side (FS) and which is to be processed at least at the rear side (RS) and the edge (RA);
• ii) block-free picking up of the blank (RL) at the rear side (RS) for supported holding of the workpiece;
• iii) processing of the blank (RL) at the front side (FS) by a first tool (WZ1) for formation of an encircling groove (NU) or step (ST) with a depth (TI) greater than or equal to the edge thickness (D2) of the semi-finished product (HZ) to be formed and smaller than the blank thickness (D1), or of an encircling cut having at least in part a depth equal to the blank thickness (D1) so that a circumferential surface (UF) defining the contoured edge (RA) of the semi-finished product (HZ) to be formed remains at the workpiece;
• iv) picking up the workpiece at the front side (FS) for supported holding of the workpiece;
• and
• v) processing the workpiece at the rear side (RS) by at least one second tool (WZ2) for formation of the semi-finished product (HZ) with the predetermined surface geometry at the rear side (RS).