Bifocal optics for structuring of engine blocks

The present invention relates to a method and an apparatus for machining a cylindrical inner surface of an internal combustion engine with a machining beam. The process of the invention relates to a processing beam for processing a cylinder inner surface of an internal combustion engine, wherein a first optical element divides the first processing beam. This first partial beam is directed to a first point on the cylinder surface. The remaining second partial beam of the machining beam is directed through a second optical element to a second point of the cylinder inner surface, it is not absolutely necessary that the machining beam is divided into exactly two sub-beams. According to the invention a division into more than two sub-beams is possible, wherein the optical element, the last hit by the processing beam preferably passes the entire remaining part beam to a point on the cylinder surface. Advantageously, the process time is thus saved; with the use of two optical elements almost halve the processing time of the cylinder surface is possible.