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US 8,012,402 B2Granted
Tube expansion process for semicrystalline polymers to maximize fracture toughness
AssigneeAbbott Cardiovascular Systems Inc.
InventorsLothar W. Kleiner, James P. Oberhauser, Thierry Glauser, David K. Wrolstad, Yunbing Wang
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Abstract
Methods of fabricating a polymeric stent with improved fracture toughness including radial expansion of a polymer tube along its entire length at the same time and fabricating a stent from the expanded tube are disclosed herein.
Claims24
A method of making a stent comprising:
- heating an axial section of a polymer tube to facilitate radial deformation of the axial section;
- radially deforming the axial section of tube to a target diameter, wherein the axial section is radially deformed along its entire length at the same time;
- actively cooling the deformed axial section to below a target temperature to stabilize the axial section at or close to the target diameter,
- wherein there is a cooling time delay between the radial deformation to the target diameter of the axial section and the start of the active cooling,
- wherein the cooling time delay is controlled by a tension sensor that senses the tension in the axial section radially or axially and the active cooling is activated when a desired tension is achieved;
- and
- fabricating a stent from the deformed axial section after the cooling.
4 more elements
A method of making a stent comprising:
- heating an axial section of a polymer tube disposed within a cylindrical mold to a deformation temperature, wherein the heating facilitates radial deformation of the axial section within the mold;
- increasing the pressure inside the axial section of the mold to a pressure that radially deforms the axial section;
- allowing the axial section to radially deform against an inner surface of the mold to a deformed diameter, wherein the axial section is radially deformed along its entire length at the same time;
- cooling the deformed axial section below a target temperature to stabilize the axial section at or close to the deformed diameter,
- wherein there is a cooling time delay between the radial deforming of the axial section against the inner surface of the mold to the target diameter and the start of the cooling,
- wherein the cooling time delay is controlled by a tension sensor that senses the tension in the axial section radially or axially and the cooling is activated when a desired tension is achieved;
- and
- fabricating a stent from the deformed axial section after the cooling.
5 more elements
Dependencies are inferred from the claim text.