Pulsed fiber laser cutting system for medical implants

Abstract

An improved expandable stent for implantation in a body lumen, such as an artery, and an improved method for making it from a single length of tubing. The stent consists of a plurality of radially expandable cut cylindrical elements generally aligned on a common axis and interconnected by one or more interconnective elements, the elements having a rectangular cross-section from cut-to-cut. The individual radially expandable cylindrical elements are disposed in an undulating pattern. The stent is manufactured by direct laser cutting from a single metal tube using a finely focused laser beam originating from a diode pumped fiber laser with an external pulse generator and passing through a coaxial gas jet structure to impinge on the working surface of the tube as the linear and rotary velocity of the tube is precisely controlled. To optimize the cut, the laser parameters may be adjusted and/or the laser pulse may be shaped.

1 - 11 . (Cancel)  
   
   
       12 . An assembly for making a stent comprising: 
 a fiber laser having an optical fiber and two or more mirrors;    a diode pump for pumping the fiber laser; and    the fiber laser configured for operating at a cutting speed within a range of about 3.0 to about 5.0 mm per second (about 0.12 to 0.20 inch per second).    
   
   
       13 . The assembly of  claim 12 , wherein a pulse generator is used to gate the diode pump.  
   
   
       14 . The assembly of  claim 13 , wherein the pulse generator is configured to deliver pulses at a frequency in the range of about 1,205 Hertz to about 1,750 Hertz.  
   
   
       15 . The assembly of  claim 13 , wherein the pulse generator is configured to pulse the laser in pulse lengths between about 0.05 ms and about 0.10 ms.  
   
   
       16 . The assembly of  claim 12 , wherein the fiber laser incorporates a coaxial gas jet configured to release compressed gas at a pressure in a range between about 130 kPa to over about 345 kPa (about 20 psi to over about 50 psi).  
   
   
       17 . The assembly of  claim 13 , wherein the pulse generator provides laser pulses having pulse lengths in increments as small as about 0.005 ms.