Milling cutter having undulating chip breaker

1. A cutting element comprising:

a front face extending between a first side and a second side;

a leading face extending between the first side and the second side;

a leading cutting edge formed at an intersection of the front face and the leading face; and

an undulating back-up cutting edge formed in the front face extending from the first side to the second side and forming a leading surface and a trailing surface, the leading surface of the undulating back-up cutting edge having a variable distance from the leading face and the leading cutting edge.

2. The cutting element as recited in claim 1 , the undulating back-up cutting edge being curvilinear.

3. The cutting element as recited in claim 2 , the undulating back-up cutting edge being substantially sinusoidal.

4. The cutting element as recited in claim 1 , the undulating back-up cutting edge being triangular.

5. The cutting element as recited in claim 1 , the undulating back-up cutting edge having a square or sawtooth profile.

6. The cutting element as recited in claim 1 , the undulating back-up cutting edge being a first undulating back-up cutting edge, the cutting element further comprising:

a second undulating back-up cutting edge formed in the front face a selected distance from the undulating back-up cutting edge and farther from the leading cutting edge than the first undulating back-up cutting edge.

7. The cutting element as recited in claim 6 , a point of the first undulating back-up cutting edge farthest from the leading cutting edge being farther from the leading cutting edge than a point of the second undulating back-up cutting edge nearest the leading cutting edge.

8. The cutting element as recited in claim 6 , the trailing surface of the first undulating back-up cutting edge intersecting a leading surface of the second undulating back-up cutting edge.

9. The cutting element as recited in claim 6 , the selected distance being measured as a difference between the distance of the undulating back-up cutting edge and the second undulating back-up cutting edge from the leading cutting edge of the cutting element, the selected distance being constant along a width of the front face.

10. A downhole tool comprising:

a tool body;

a first blade coupled to the tool body, the first blade having a forward surface; and

a cutting element coupled to the forward surface of the first blade, the cutting element having:

a front face extending between a first side and a second side;

a leading face extending between the first side and the second side;

a leading cutting edge formed at an intersection of the front face and the leading face; and

a first undulating back-up cutting edge formed in the front face extending from the first side to the second side and forming a leading surface and a trailing surface, the leading surface of the first undulating back-up cutting edge having a variable distance from the leading cutting edge.

11. The cutting element as recited in claim 10 , the undulating back-up cutting edge being substantially sinusoidal.

12. The cutting element as recited in claim 10 , the undulating back-up cutting edge being triangular.

13. The downhole tool as recited in claim 10 , further comprising:

a second blade coupled to the tool body and spaced azimuthally from the first blade, the second blade having a forward surface; and

a second cutting element coupled to the forward surface of the second blade, the second cutting element having an undulating back-up cutting edge, the second cutting element being offset radially from the first cutting element coupled to the first blade.

14. The downhole tool as recited in claim 10 , further comprising:

a second cutting element having an undulating back-up cutting edge, the second cutting element being positioned adjacent to the first cutting element such that the undulating back-up cutting edge of the second cutting element aligns with the undulating back-up cutting edge of the first cutting element so that the undulating back-up cutting edges of the first and second cutting elements form a substantially continuous undulating back-up cutting edge profile across the interface between the first and second cutting elements.

15. The downhole tool as recited in claim 10 , further comprising:

a plurality of additional cutting elements, each cutting element of the plurality of additional cutting elements having an undulating back-up cutting edge, the plurality of cutting elements extending both in radial and longitudinal directions over the forward surface of the first blade.

16. A method of cutting with a downhole tool comprising:

deploying a downhole tool to a downhole position in a borehole, the downhole tool having:

a tool body;

a blade coupled to the tool body having a forward surface; and

a cutting element coupled to the forward surface of the blade, the cutting element having:

a leading cutting edge formed at an intersection of a front face and a leading face of the cutting element; and

an undulating back-up cutting edge formed in the front face extending from a first side to a second side of the cutting element and forming a leading surface and a trailing surface, the leading surface of the undulating back-up cutting edge having a variable distance from the leading cutting edge;

contacting the leading cutting edge of the cutting element with a work piece; and

rotating and translating the downhole tool.

17. The method as recited in claim 16 , further comprising:

shaving a chip from the work piece using the leading cutting edge of the cutting element; and

breaking the chip from the work piece by contacting the chip with the leading surface of the undulating back-up cutting edge.

18. The method as recited in claim 17 , further comprising:

eroding the leading face of the cutting element, the eroding forming:

a second leading face of the cutting element, and

a second leading cutting edge formed at an intersection of the front face and the second leading face of the cutting element.

19. The method as recited in claim 18 , further comprising:

eroding a portion of the undulating back-up cutting edge;

shaving a second chip from the work piece with the second leading cutting edge; and

breaking the second chip from the work piece by contacting the second chip with a second leading surface of a second undulating back-up cutting edge, the second undulating back-up cutting edge being formed in the front face a selected distance from the undulating back-up cutting edge.

20. The method as recited in claim 19 , the cutting element further having a second undulating back-up cutting edge formed in the front face a selected distance from the undulating back-up cutting edge, the selected distance optimizing an average chip size.

21. The method as recited in claim 20 , the work piece including one or more of a plug, tubular, downhole restriction, broken tool component, or hand tool.