Method for producing cylindrical lattice structures, in particular, for stents by laser beam cutting of thin-walled tubes, with an additional tube inserted into the tube to be cut and removed from it after completion of the cutting process

摘要

An additional tube is inserted into the tube to be cut. The outer tube of the resulting compound tube is cut by means of a laser beam. The inner tube is removed after completion of the cutting process, leaving the outer tube in the form of a desired cylindrical lattice structure. Preferred Features: The additional tube is inserted into outer tube without gap. The inner tube consists of a material which differs from that of the outer tube. For easier removal, the inner tube has a smaller wall thickness than the outer tube. The inner tube is removed by chemical and/or mechanical means. The inner tube is removed by shot blasting with an aggressive material. Alternatively it is dissolved by acids. The inner tube has a higher elasticity than the outer tube. For removal, it is first radially expanded and then left to contract. Alternatively the inner tube consists of a brittle material which is broken into pieces when expanded. The inside diameter of the outer tube varies from 1 to 8 mm, while the tube wall thickness varies from 50 mu m to 300 mu m. As an alternative to the inner tube, the outer tube can be filled with a synthetic material. Some of this material is evaporated by the laser beam during the cutting process, leaving the rest to be removed by chemical or mechanical means.