HIGH PRECISION 2.5D LASER CUTTING OF THIN NITINOL AND POLYURETHANE FOR MEDICAL APPLICATIONS

摘要

High precision laser cutting is extensively used in many medical applications. Materials like polyurethane and nitinol operate as catheters, heart valves, stents or systems combined of both materials. Cardiac heart valves designed as percutaneous heart valves offer an option to treat congenital heart defects of the pulmonary valve with lower risk than an openheart- surgery. Innovative heart valves used for these applications are built of polyurethane and nitinol. Laser cutting can provide a crack-free cutting of thin polyurethane as well as high precision cutting of nitinol. Industrial cutting machines that can fulfill that range of tasks are highly expensive. Hence the objective is to design a laser machining center for less than $ 200 k that is able to cut metal materials as well as non-metal materials at economic speed with a precision higher than 2μm. Therefore a cw-laser at a wavelength of 10.6 μm and a short pulsed Ytterbium fiber laser at 1.06 μm operate within the entire system. Both laser sources can be used alternately during each process. The processes take place on complex 2.5D surfaces and therefore require precise and well controlled movement of four axes simultaneously. The intention is to increase the quality of the cutting surface and to avoid any micro cracking on the surrounding material.