Laser polishing of medical devices

• US 6,492,615 B1
• Filed: 10/12/2000
• Issued: 12/10/2002
• Est. Priority Date: 10/12/2000
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Flanagan, Aiden
• Primary Examiner(s): Dunn, Tom
• Assistant Examiner(s): PITTMAN, ZIDIA T
• Application Number:
  US09/689,142
• Time in Patent Office: 789 Days
• Field of Search: 219/121.6, 219/121.61, 219/121.62, 219/121.64, 219/121.65, 219/121.66, 219/121.85, 219/121.86, 219/92, 219/121.8, 427/554-556
• US Class Current: 219/121.66
• 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: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/91541 Adjacent bands are arranged out of phase
• CPC Class Codes: B23K 2103/05 Stainless steel
• CPC Class Codes: B23K 2103/14 Titanium or alloys thereof
• CPC Class Codes: B23K 26/066 by using masks
• CPC Class Codes: B23K 26/12 in a special atmosphere, e.g. in an enclosure
• CPC Class Codes: B23K 26/1224 in vacuum
• CPC Class Codes: B23K 26/123 in an atmosphere of particular gases
• CPC Class Codes: B23K 26/127 in an enclosure
• CPC Class Codes: B23K 26/3576 Diminishing rugosity, e.g. grinding; Polishing; Smoothing

Abstract

A desired portion of a stent may be polished by irradiating at least a portion of the surface of the stent substrate with a laser beam from the laser at a wavelength absorbed by the stent substrate to cause a controlled level of melting of the surface of the stent substrate and allowing the substrate material to solidify.

Claims

1. A method of polishing at least a portion of a stent substrate comprising the steps of:

providing a stent substrate;

providing a laser operating at a wavelength absorbable by the stent substrate; and

irradiating at least a portion of the surface of the stent substrate with a laser beam from the laser at a wavelength absorbed by the stent substrate to cause a controlled level of melting of the surface of the stent substrate; and

allowing the substrate material to solidify.

2. The method of claim 1 further comprising the step of providing an inert gas about the stent during the irradiating step.

3. The method of claim 2 wherein the surface of the stent substrate comprises stainless steel.

4. The method of claim 1 wherein the stent substrate is placed in a chamber prior to the irradiating step and the chamber evacuated prior to the irradiating step.

5. The method of claim 4 wherein the stent substrate is maintained in a vacuum during the irradiating step.

6. The method of claim 5 wherein the surface of the stent substrate comprises stainless steel.

7. The method of claim 1 wherein the entirety of the stent substrate is polished.

8. The method of claim 7 wherein the laser is scanned across a portion of the stent substrate.

9. The method of claim 1 wherein the laser is pulsed.

10. The method of claim 1 wherein the laser is a continuous laser and the laser beam is modulated.

11. The method of claim 10 wherein the laser beam is modulated by a shutter.

12. The method of claim 11 wherein the shutter is mechanical or optical.

13. The method of claim 1 wherein the stent substrate is made of polymeric material.

14. The method of claim 13 wherein the laser is an excimer laser or a CO₂ laser.

15. The method of claim 1 wherein the stent substrate is made of metal.

16. The method of claim 1 wherein the stent comprises a coating.

17. The method of claim 16 wherein the coating is gold.

18. The method of claim 1 further comprising the step of electropolishing at least a portion of the stent substrate.

19. The method of claim 1 wherein the stent substrate is a sheet, the method further comprising the steps of rolling the sheet and welding the sheet to form a tube.

20. The method of claim 19 wherein the sheet has pattern cut therein via a method selected from the group consisting of laser etching, chemical etching, mechanical cutting and electrodischarge machining.

21. The method of claim 1 wherein the stent substrate is a tube.

22. The method of claim 21 wherein the tube has a pattern cut therein via a method selected from the group consisting of laser etching, chemical etching, mechanical cutting and electrodischarge machining.

23. The method of claim 1 wherein the stent substrate has an inner surface and an outer surface and the laser beam is directed at a portion of the inner surface of the stent to polish the portion of the inner surface of the stent.

24. The method of claim 1, the stent substrate having an inner surface, an outer surface and a plurality of side surfaces extending between the inner surface and the outer surface, wherein the laser beam is directed at a portion of at least one of the side surfaces of the stent to polish the portion of the side surface.

25. The method of claim 24 wherein all of the side surfaces are polished.

26. The method of claim 1, the stent substrate having an inner surface, an outer surface a plurality of side surfaces extending between the inner surface and the outer surface and a plurality of edges, the edges formed at the intersections of the inner surface and the side surfaces and at the intersections of the outer surface and the side surfaces wherein the laser beam is directed at a portion of at least one edge to polish the portion of the edge.

27. The method of claim 26 wherein all of the edges are polished.

28. A method of polishing at least a portion of a stent substrate comprising the steps of:

providing a stent substrate;

providing a laser operating at a wavelength absorbable by the stent substrate;

directing a laser beam output from the laser at a portion of the stent substrate, the laser beam characterized by a fluence of between about 1 J/cm² and 5000 J/cm², wherein the wavelength of the laser beam absorbed by the stent substate causes a controlled level of melting of the surface of the stent substrate.

29. The method of claim 28 wherein the laser is pulsed.

30. The method of claim 28 wherein the laser beam is characterized by an intensity of between 10⁴ and 10⁶ Watts/cm².

31. A method of polishing at least a portion of a stent substrate comprising the steps of:

providing a stent substrate;

providing a laser operating at a wavelength absorbable by the stent substrate;

directing a laser beam output from the laser at a portion of the stent substrate, the laser beam melting a surface layer of the stent substrate to a depth of no greater than 5 percent of the thickness of the stent substrate in the portion of the stent substrate impinged by the laser beam.

32. A method of polishing at least a portion of a medical guidewire for use with a catheter comprising the steps of:

providing a medical guidewire;

providing a laser; and

irradiating the surface of the guidewire with a beam of radiation from the laser at a wavelength absorbed by the guidewire to cause a controlled level of melting of the surface of the guidewire in the portion of the guidewire impinged by the laser beam; and

allowing the surface of the guidewire to solidify.

33. A method of polishing at least a portion of a guidewire comprising the steps of:

providing a guidewire;

providing a laser operating at a wavelength absorbable by the guidewire;

directing a laser beam output from the laser at a portion of the guidewire, the laser beam melting a surface layer of the guidewire to a depth of no greater than 5 percent of the thickness of the guidewire in the portion of the guidewire impinged by the laser beam.

34. A method of polishing at least a portion of a component for use with a catheter system comprising the steps of:

providing the component for use with a catheter system;

providing a laser operating at a wavelength absorbable by the component for use with a catheter system;

directing a laser beam output from the laser at a portion of the component for use with a catheter system, the laser beam melting a surface layer of the component for use with catheter system to a depth of no greater than 5 percent of the thickness of the component in the portion of the component impinged by the laser beam.

35. The method of claim 34 wherein the component is a stent or vena cava filter.

36. The method of claim 34 wherein the component is a guidewire.