| 摘要 |
PURPOSE: To reduce cost by preventing spatter incident to work from melt- sticking to the nozzle by covering the nozzle with a cap and thereby replacing with a minimum unit of parts when the spatter gives damage to the cap. CONSTITUTION: In the case of machining by injecting, from an orifice 7a formed on a nozzle 7, a plasma arc which is formed by a discharge between an electrode 3 and a material to be worked, a cover member 8, for which a hole 8a is formed opposite to the orifice 7a formed on the nozzle 7 and slightly larger than the orifice 7a, and which is closely in contact with the upper tip end tube part 7b and the tapered part 7e of the nozzle 7, is fixed to a cassette A freely attachably and detachably by means of a cap body 12. On the surface of the cover member 8, at least the contact surface with the nozzle or on the surface of the nozzle 7 in contact with the cover member 8, an insulation treatment is applied by superposedly coating with ceramic and tetrafluoro ethylene resisn.
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