Researchers have developed a direct laser welding process for joining PEEK-Optima parts for medical devices. The joint design must be optimized to produce hermetic joints. Sections of PEEK greater than 1 mm are not amenable to tranmission laser welding because the high crystallinity scatters the laser light. Cylindrical parts are spun in a specialized rig under inert gas during the welding process. Hermetic welds were produced with 10s of weld time.