Method of surface finishing orthopedic implant devices
AssigneeZimmer, Inc.
InventorsH. Ravindranath Shetty, John H. Hiss, Kevin M. Greig
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Abstract
A surface treatment process for stainless steel orthopedic implant devices and an orthopedic implant device surface treated in accordance with the disclosed process are disclosed. A rough ground or machined stainless steel part is shot blasted with stainless steel shot. The device is then shot blasted with glass beads having a nominal size of between one-tenth and one-half that of the stainless steel shot. Electropolishing and passivation follow the shot blasting steps. A part thus treated includes a heavily cold-worked outer layer that enhances the fatigue properties of the stainless steel orthopedic implant device.
Claims9
A method manufacturing an orthopaedic implant device having enhanced fatigue properties, comprising the steps of:
- providing a metal substrate in the form of an orthopaedic implant device with an outer surface;
- shot blasting said outer surface of said metal substrate with metal shot until a distinct cold-worked outer layer is formed on said metal substrate, said cold-worked layer having a textured outer surface;
- shot blasting said textured outer surface of said cold-worked outer layer with glass bead shot after shot blasting with metal shot is completed;
- and
- electropolishing said textured outer surface.
A method of increasing the fatigue strength of an orthopaedic implant device which has an outer surface, comprising the steps of:
- shot blasting the outer surface with a first shot having a first nominal size;
- after shot blasting the outer surface with the first shot, shot blasting the outer surface with a second shot having a second nominal size less than said first nominal size;
- and
- after shot blasting the outer surface with the second shot, electrpolishing the outer surface.
An orthopaedic implant device having enhanced fatigue properties, prepared by a process comprising the steps of:
- providing a metal substrate on the orthopaedic implant device, said metal substrate having a generally smooth outer surface;
- shot blasting said smooth outer surface of said metal substrate with metal shot until a distinct cold-worked outer layer is formed on said metal substrate, said cold-worked outer layer having a textured outer surface following said shot blasting;
- shot blasting said textured outer surface of said cold-worked outer layer with glass bead shot;
- and
- electropolishing said textured outer surface.
Dependencies are inferred from the claim text.