Granted Patent B2

US 7,905,161 · App. 12/141,802 · Granted Mar 15, 2011

Abstract

Claims (49)

1. A method for making drill bits, comprising:

assembling a crown by mixing a plurality of matrix particles, a plurality of cutting particles, and a binder;

positioning a mandrel adjacent the crown;

heating the crown and the mandrel within a belt furnace;

removing the heated crown and the mandrel from the belt furnace and transferring the heated crown and the mandrel to a press while the binder is molten using an automated device;

pressing the heated crown and the mandrel together while the binder is molten; and

cooling the crown and the mandrel to form a drill bit.

2. The method of claim 1 , wherein a temperature of the belt furnace is substantially continuous along a length of the belt furnace.

3. The method of claim 2 , wherein the temperature along the length of the belt furnace varies less than about 15 degrees from a target temperature.

4. The method of claim 1 , wherein heating the crown and the mandrel within belt furnace includes moving the crown and the mandrel through a front section having a front temperature, a center section having a center temperature, and an end section having an end temperature, wherein the front temperature varies from between about −100 degrees F. to about −500 degrees F. from a target temperature, the center temperature varies from about −100 degrees F. to about −300 degrees F. from the target temperature, and the end temperature varies from about −100 degrees F. to about +10 degrees F. from the target temperature.

5. The method of claim 4 , wherein the target temperature is about 2000 degrees F.

6. The method of claim 1 , further comprising introducing inert air to the belt furnace.

7. The method of claim 1 , further comprising pressing the mandrel into the heated crown while the binder is molten.

8. The method of claim 7 , further comprising placing a mixture of the binder, the plurality of matrix particles, and the plurality of cutting particles in a mold.

9. The method of claim 8 , wherein the mold is configured to form a coring drill bit.

10. The method of claim 1 , wherein a belt of the belt furnace is configured to move at different rates along different portions of the belt furnace.

11. The method of claim 1 , wherein the heated crown is exposed to the atmosphere when removed from the belt furnace.

12. A continuous process for making core drill bits, comprising:

placing a drill bit assembly on a belt of a belt furnace, the drill bit assembly comprising a matrix, a plurality of cutting elements, a binder, and a mandrel;

transporting the drill bit assembly through the belt furnace using the belt, thereby heating the drill bit assembly to a process temperature, wherein the process temperature is at least a temperature high enough to melt the binder;

removing and transferring the heated drill bit assembly from the belt furnace to a press using an automated process while the heated drill bit assembly is at the process temperature; and

pressing the heated drill bit assembly while the drill bit assembly is at approximately the process temperature.

13. The process of claim 12 , further comprising cooling the pressed drill bit assembly.

14. The process of claim 13 , wherein a cooling press is used during the cooling.

15. The process of claim 12 , further comprising monitoring the process temperature of the belt furnace.

16. The process of claim 12 , wherein the automated process includes a robotic arm.

17. The process of claim 12 , wherein an atmosphere within the belt furnace is kept under substantially inert conditions.

18. The process of claim 12 , wherein the atmosphere within the belt furnace is kept under a reducing environment.

19. The process of claim 12 , wherein the belt furnace comprises at least two furnace sections with each section being maintained at a different temperature.

20. The process of claim 12 , wherein any temperature of the belt furnace is less than about 2500 degrees Fahrenheit.

21. The method of claim 12 , wherein the drill bit assembly is exposed to the atmosphere when removed from the belt furnace.

22. The method of claim 12 , further comprising pressing the heated drill bit assembly within a cooling press.

23. A method of forming drill bits, comprising:

preparing a drill bit assembly comprising tungsten carbide, a copper-based binder, and a blank;

sequentially loading the drill bits assembly on a belt associated with a belt furnace;

sequentially heating the drill bits assembly to a temperature sufficient to bring the binder to a molten state;

sequentially unloading the drill bits assembly from the belt furnace and transferring the drill bit assembly to a press with an automated unloader while the binder is in the molten state; and

pressing the drill bit assembly while the binder of the drill bit assembly is in the molten state.

24. The method of claim 23 , further comprising cooling the drill bit assembly.

25. The method of claim 24 , further comprising cooling the drill bit assembly in a water circulation cooling press.

26. The method of claim 25 , wherein said step of cooling the drill bit assembly includes cooling the drill bit assembly with water at a temperature of about 100 degrees F. and in an environment having a pressure of about 1000 p.s.i.

27. The method of claim 23 , wherein the belt furnace is operated with a target temperature of about 2000 degrees F.

28. The method of claim 23 , wherein the drill bit assembly is exposed to the atmosphere when unloaded from the belt furnace.

29. A method of manufacturing drill bits, comprising:

placing a mixture of a plurality of matrix particles, a plurality of cutting particles, and a binder within an annular mold;

placing an annular mandrel adjacent the mixture;

heating the mixture and the annular mandrel within a belt furnace having an inert or reducing environment;

removing the heated mixture and mandrel from the belt furnace and transferring the heated mixture and mandrel to a press while the binder is molten thereby exposing the heated mixture to the atmosphere; and

pressing the mandrel into the heated mixture while the binder is molten.

Assignments (11)