High Strength Injection Molded Orthopedic Devices
AssigneePraxis Power Technology, Inc.
InventorJoseph A. Grohowski, JR.
Life of this patent
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Abstract
High strength implantable devices having complex surfaces are injection molded from powder metal wherein the surface is defined by a monolithic insert made by additive manufacturing. The insert defines the surface texture of the device and may also include a portion to form an ingrowth texture and a portion to form a substrate interface texture. The tensile bond strength of the texture is 20 Mega Pascal or greater.
Claims19
A method of forming an implantable device or part thereof, such method comprising the steps of:
- blending a binder and a first powder of metal particles to form a first homogeneous mixture;
- forming a monolithic mold insert by an additive process, wherein the insert has a complex texture;
- placing the mold insert in a mold;
- injection molding the first homogeneous mixture into the mold and the mold insert to form an article, wherein the mold insert forms a textured portion in the article;
- removing the article and the insert from the mold;
- removing the insert from the article;
- and
- sintering the article to form the implantable device, wherein the textured portion has tensile bond strength of 20 Mega Pascal or greater.
A method of forming a textured portion of an implantable device, such method comprising the steps of:
- blending a binder and a powder of metal particles to form a homogeneous mixture;
- forming a monolithic mold insert by an additive manufacturing process having a first surface for making contact with a mold and a second surface having a texture;
- placing the insert in a mold such that the first surface is in contact with the mold;
- injection molding the homogeneous mixture into the mold to form an article having a textured portion defined entirely by the second surface of the mold insert;
- removing the article and the mold insert from the mold;
- removing the insert so as to maintain the textured portion on the article;
- and
- sintering the article to form the implantable device with the textured portion.
An textured implantable device comprising:
- a fixation texture comprising an array of protruding undercut features,
- an ingrowth portion with a porosity between 60 and 85 percent, and
- an interface region to a dense portion of the device,
- wherein the tensile bond strength of the ingrowth portion is at least 50 Mega Pascal.
A monolithic mold insert for metal injection molding adapted to form a complex implantable device comprising:
- a portion to form a fixation texture comprising undercuts on the device, wherein such texture is defined entirely by the insert;
- a portion to form an ingrowth medium on the device comprising fused pore formers;
- and
- a portion to form an interface with reduced stress concentrators to a dense portion the device.
Dependencies are inferred from the claim text.