Methods of designing molds for machining cost reduction

Patent metadata

Field	Value
Publication number	US-9421018-B2
Application number	US-201214359621-A
Country	US
Kind code	B2
Filing date	Nov 20, 2012
Priority date	Nov 21, 2011
Publication date	Aug 23, 2016
Grant date	Aug 23, 2016

Abstract

An orthopaedic knee cutting block prepared by a process comprising the steps of: creating a mold with a first core detail and a second core detail, each of the core details corresponding to a volume; filling the mold with a mixture of a binder and a metal; releasing a green part from the mold, the green part having a first void corresponding to the first core detail and a second void corresponding to the second core detail; removing the binder from the green part; heating the green part to create a sintered part; and machining the part by sawing a cutting slot such that the cutting slot overlaps with the first void and the second void. Alternatively, the orthopaedic knee cutting instrument may be made by a simple metal casting method.

First claim

What is claimed is:

1. A method of preparing an orthopaedic knee cutting block, the method comprising the steps of:
a. creating a mold with a first core detail and a second core detail, each of the core details corresponding to a volume;
b. filling the mold with a mixture of a binder and a metal;
c. releasing a green part from the mold, the green part having a first void corresponding to the first core detail and a second void corresponding to the second core detail;
d. removing the binder from the green part;
e. heating the green part to create a sintered part, the sintered part including a region between the first void and the second void, the region including a first section of material and a second section of material; and
f. plunging a slitting saw into the sintered part to remove the first section of material from the region between the first void and the second void, thereby forming a cutting slot which overlaps with the first void and the second void;
wherein the orthopaedic knee cutting block includes the second section of material in the region between the first void and the second void.

2. The method of claim 1 , wherein the first and second core details are located on a proximal portion.

3. The method of claim 1 , wherein the cutting slot is an anterior cutting slot.

4. The method of claim 1 , wherein the orthopaedic knee cutting block further comprises a posterior cutting slot.

5. The method of claim 1 , wherein the orthopaedic knee cutting block further comprises at least one chamfer cut slot.

6. The method of claim 1 , wherein the orthopaedic knee cutting block further comprises a spike and a countersink formed at the base of the spike.

7. The method of claim 1 , wherein the volumes corresponding to the first and second core details correspond to volumes of the sintered part that cannot be removed by plunging the slitting saw to form the cutting slot.

8. The method of claim 7 , wherein the cutting block comprises a captive including the first void, the second void, the cutting slot, and the volumes of the sintered part that cannot be removed by plunging the slitting saw to form the cutting slot.

9. The method of claim 1 , wherein the first void, the second void, and the cutting slot define a captive including a first edge defined by a wall of the first void and a second edge defined by a wall of the second void.

10. A method of manufacturing an orthopedic knee cutting block instrument comprising:
a. creating a mold with a core detail;
b. filling the mold with a mixture of a binder and a metal;
c. releasing a green part from the mold, the green part having a void created by the core detail;
d. removing the binder from the green part;
e. heating the green part to create a sintered part; and
f. plunging a slitting saw to form a slot in the sintered part, wherein the slot intersects the void;
wherein the void created by the core detail corresponds to a volume which is aligned with the slot and cannot be removed from the sintered part by the plunging.

11. The method of claim 10 , wherein the core detail is located on a proximal portion.

12. The method of claim 10 , wherein the slot is an anterior cutting slot.

13. The method of claim 10 , wherein the creating further includes creating the mold with a second core detail, wherein the green part has a second void created by the second core detail, wherein the slot further intersects the second void, and wherein a captive is defined by the void, the second void, and the slot.

14. A method of manufacturing an orthopedic knee cutting block instrument comprising:
a. creating a mold with a core detail corresponding to a volume;
b. filling the mold with a molten metal;
c. allowing the molten metal to solidify to produce a part;
d. releasing the part from the mold, the part having a void corresponding to the core detail; and
e. plunging a slitting saw to form a slot in the part, wherein the slot intersects the void.

15. The method of claim 14 , wherein the core detail is located on a proximal portion.

16. The method of claim 14 , wherein the slot is an anterior cutting slot.

17. The method of claim 13 , wherein the captive is formed solely by plunging the slitting saw such that the slot intersects the void and the second void.

Assignees

• Smith & Nephew Inc

Inventors

• Porzel Alec Paul
• Dyer Robert H
• Lux Thomas William

Classifications

• A61B17/154 Primary

  for preparing bone for knee prosthesis · CPC title

• B22F2003/245

  Making recesses, grooves etc on the surface by removing material · CPC title

• B22F3/225

  by injection molding · CPC title

• Y10T29/4998

  Combined manufacture including applying or shaping of fluent material · CPC title

• A61B17/155

  Cutting femur · CPC title