Method of cutting super-hard materials using an electron beam and a range of beam scanning velocities
A method of cutting a super-hard material ( 8 ) using an electron beam ( 6 ), wherein the electron beam ( 6 ) is directed onto a surface of the super-hard material ( 8 ) and moved relative to the surface such that the electron beam ( 6 ) moves across the surface of the super-hard material ( 8 ) at an electron beam scanning velocity in a range 100 to 5000 mms −1 to cut the super-hard material ( 8 ).
1. A method of cutting a super-hard material using an electron beam, wherein the electron beam is directed onto a surface of the super-hard material and moved relative to the surface such that the electron beam moves across the surface of the super-hard material at an electron beam scanning velocity in a range 100 to 5000 mms −1 to cut the super-hard material, wherein the electron beam has a beam current in a range 5 mA to 120 mA, wherein the electron beam has an accelerating voltage in a range 10 kV to 200 kV, wherein the electron beam has a spot size at a point of contact on the super-hard material no more than 500 μm, wherein the electron beam has an input line energy, as defined by (accelerating voltage×beam current)/(electron beam scanning velocity), in a range 500 to 30000 Jm −1 , wherein the electron beam has a surface energy density, as defined by (accelerating voltage×beam current)/(electron beam scanning velocity×beam width), in a range 10 to 600 MJm −2 , wherein the electron beam applies an energy per unit volume of super-hard material which is volatilized, as defined by (accelerating voltage×beam current)/(electron beam scanning velocity×cut cross-sectional area), in a range 100 to 2500 GJm −3 .
2. The method according to claim 1 , wherein the electron beam is collimated with a half angle divergence of no more than 5 degrees, 3 degrees, or 1 degree.
3. The method according to claim 1 , wherein the electron beam scanning velocity is no less than 200 mms −1 , 400 mms −1 , 600 mms −1 , 800 mms −1 , 1000 mms −1 , 1200 mms −1 , or 1400 mms −1 .
4. The method according to claim 1 , wherein the electron beam scanning velocity is no more than 4500 mms −1 , 4000 mms −1 , 3500 mms −1 , 3000 mms −1 , 2500 mms −1 , 2000 mms −1 , 1800 mms −1 , or 1600 mms −1 .
5. The method according to claim 1 , wherein the beam current is no less than 10 mA, 15 mA, 20 mA, 30 mA, 40 mA, 50 mA, 60 mA, or 70 mA.
6. The method according to claim 1 , wherein the beam current is no more than 110 mA, 100 mA, 90 mA, 85 mA, or 80 mA.
7. The method according to claim 1 , wherein the accelerating voltage is no less than 15 kV, 20 kV, 25 kV, 30 kV, or 35 kV.
8. The method according to claim 1 , wherein the accelerating voltage is no more than 150 kV, 125 kV, 100 kV, 90 kV, 80 kV, 70 kV, or 65 kV.
9. The method according to claim 1 , wherein the spot size of the electron beam at the point of contact on the super-hard material is no more than 300 μm, 100 μm, 50 μm, or 30 μm.
10. The method according to claim 1 , wherein the input line energy of the electron beam is in a range 800 Jm −1 to 25000 Jm −1 , 1100 Jm −1 to 20000 Jm −1 , 1500 Jm −1 to 15000 Jm −1 , 2000 Jm −1 to 10000 Jm −1 , or 3000 Jm −1 to 5000 Jm −1 .
11. The method according to claim 1 , wherein the surface energy density of the electron beam is in a range 16 MJm −2 to 500 MJm −2 , 22 MJm −2 to 400 MJm −2 , 30 MJm −2 to 300 MJm −2 , 40 MJm −2 to 200 MJm −2 , or 60 MJm −2 to 100 MJm −2 .
12. The method according to claim 1 , wherein the energy per unit volume of super-hard material which is volatilized applied by the electron beam is in a range 150 GJm −3 to 2300 GJm −3 , 200 GJm −3 to 2000 GJm −3 , 250 GJm −3 to 1700 GJm −3 , 300 GJm −3 to 1400 GJm −3 , 350 GJm −3 to 1100 GJm −3 , 400 GJm −3 to 800 GJm −3 , or 500 GJm −3 to 600 GJm −3 .
13. The method according to claim 1 , wherein during formation of a cut line in the super-hard material the electron beam is periodically moved to a beam dump and then returned to the cut line to continue cutting.
14. The method according to claim 1 , wherein during the formation of a first cut line in the super-hard material the electron beam is periodically moved to one or more other locations on the surface of the super-hard material or to another sample of super-hard material to form one or more further cut lines and then returned to the first cut line to continue cutting, periodic switching of the electron beam between cut lines achieving parallel cutting of two or more cut lines in the surface of one or more samples of super-hard material, and wherein the electron beam is a continuous electron beam.
15. The method according to claim 1 , wherein the electron beam is a pulsed electron beam.
16. A method according to claim 1 , wherein the super-hard material comprises one or more of: a diamond material; a cubic boron nitride material; sapphire; or a composite material comprising one or more of the aforementioned super-hard materials and a binder.
17. The method according to claim 16 , wherein the super-hard material comprises at least 50%, 60%, 70%, 80%, 90%, 95%, or 99% by weight of the diamond material, and wherein the accelerating voltage of the electron beam is no more than 80 kV and the diamond material is cut via a thermal cutting mode forming a coating of graphite at sides of a cut region.