Plasma machining electrode and plasma machining device
AssigneeKomatsu Industries Corporation
InventorsYoshihiro Yamaguchi, Kazuhiro Kuraoka, Tetsuya Kabata
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Abstract
The invention prolongs the electrode lifetime of plasma machining electrodes having a hafnium or zirconium insert. A hafnium or zirconium insert 21 inserted into the tip of a copper holder 22 protrudes from the tip of the copper holder 22. The protrusion length L is not larger than the diameter D of the insert, preferably not larger than 0.5 mm. The protruding portion 21a of the insert has a rounded section without sharp angles. The rear surface 21 of the insert is exposed to the flow of the cooling water inside the electrode. At least during the generation of the pilot arc, a plasma gas containing at least 5 mol % nitrogen is used.
Claims6
A structure of a plasma machining electrode, comprising:
- a holder serving as an electrode body;
- a permanent insert inserted into a tip of the holder and joined therewith;
- wherein the material of the insert is selected from group consisting of hafnium, zirconium, hafnium alloys and zirconium alloys;
- wherein the insert has a protruding portion that protrudes from a top surface of the holder;
- wherein the insert is substantially cylindrical;
- and
- wherein an entire protrusion length that the protruding portion of the insert protrudes from the holder top surface is not larger than a diameter of the insert.
A plasma machining electrode, comprising:
- a holder serving as an electrode body;
- a permanent insert including an inserted portion that is inserted into a tip of the holder and joined therewith, and a protruding portion that protrudes from a top surface of the holder;
- wherein the material of the insert is selected from the group consisting of hafnium, zirconium, hafnium alloys and zirconium alloys;
- and
- wherein a length of the protruding portion of the insert is not longer than a length of the inserted portion.
Dependencies are inferred from the claim text.