Pulsed fiber laser cutting system for medical implants

• US 6,927,359 B2
• Filed: 02/18/2003
• Issued: 08/09/2005
• Est. Priority Date: 06/14/2001
• Status: Expired due to Fees

• Current Assignee: Advanced Cardiovascular Systems Incorporated (Abbott Laboratories)
• Original Assignee: Advanced Cardiovascular Systems Incorporated (Abbott Laboratories)
• Inventors: Kleine, Klaus, Fox, Jason, Jones, Stephen, Ku, Yu-Chun, Whitney, Brad
• Primary Examiner(s): Heinrich, Samuel M.
• Application Number:
  US10/369,358
• Publication Number:
  US 20040089643A1
• Time in Patent Office: 903 Days
• Field of Search: 219/121.67, 219/121.72, 219/121.73, 219/121.74, 219/121.75, 219/121.85, 606/194, 606/195, 623/1.1, 623/1.15, 623/1.17, 623/1.3, 623/1.31
• US Class Current: 219/121.72
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: B23K 2101/06 Tubes
• CPC Class Codes: B23K 2103/05 Stainless steel
• CPC Class Codes: B23K 2103/42 Plastics B23K2103/16 takes precedence
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/06 Shaping the laser beam, e.g. by masks or multi-focusing
• CPC Class Codes: B23K 26/0622 by shaping pulses
• CPC Class Codes: B23K 26/064 by means of optical elements, e.g. lenses, mirrors or prisms
• CPC Class Codes: B23K 26/08 Devices involving relative movement between laser beam and workpiece
• CPC Class Codes: B23K 26/123 in an atmosphere of particular gases
• CPC Class Codes: B23K 26/14 using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor B23K26/12 takes precedence
• CPC Class Codes: B23K 26/142 for the removal of by-products
• CPC Class Codes: B23K 26/1436 for pressure control
• CPC Class Codes: B23K 26/1438 for directional control
• CPC Class Codes: B23K 26/146 the fluid stream containing a liquid
• CPC Class Codes: B23K 26/1476 Features inside the nozzle for feeding the fluid stream through the nozzle
• CPC Class Codes: B23K 26/16 Removal of by-products, e.g. particles or vapours produced during treatment of a workpiece by a fluid stream B23K26/142
• CPC Class Codes: B23K 26/18 using absorbing layers on the workpiece, e.g. for marking or protecting purposes
• CPC Class Codes: B23K 26/38 by boring or cutting

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.

Claims

1. A method of making a stent, comprising:

providing a generally tubular member;

providing a fiber laser having,

an optical fiber; and

two or more mirrors;

pumping said fiber laser using a diode pump; and

cutting a predetermined pattern in the tubular member using the fiber laser at a cutting speed within a range of about 3.0 to about 5.0 mm/second (about 0.12 to about 0.20 inch/second).

2. The method of claim 1, further comprising gating the pump using a pulse generator.

3. The method of claim 2, further comprising pulsing the pulse generator at a frequency in the range of about 1250 to about 1750 Hertz.

4. The method of claim 2, wherein the pulse generator provides laser pulses having pulse lengths between about 0.05 and about 0.10 milliseconds.

5. The method of claim 1, wherein:

providing a fiber laser further comprises providing a fiber laser incorporating a coaxial gas jet; and

cutting a predetermined pattern in the tubular member further comprises releasing a compressed gas from the gas jet at a pressure within a range between about 138 kPa to over about 345 kPa (about 20 psi to over about 50 psi).

6. The method of claim 1, further comprising pumping a liquid through the tubular member.

7. A method of making a stent, comprising:

providing a generally tubular member;

providing a fiber laser having,

an optical fiber; and

two or more mirrors;

pumping said fiber laser using a diode pump;

cutting a predetermined pattern in the tubular member using the fiber laser; and

shaping the laser during a laser pulse.

8. The method of claim 7, further comprising gating the pump using a pulse generator.

9. The method of claim 8, wherein the pulse generator provides laser pulses having pulse lengths between about 0.02 and about 0.20 milliseconds.

10. The method of claim 9, wherein shaping the pulse includes modifying the pulse in increments as small as about 0.005 milliseconds.

11. The method of claim 7, further comprising pumping a liquid through the tubular member.