| 摘要 |
PCT No. PCT/JP91/00513 Sec. 371 Date Oct. 19, 1992 Sec. 102(e) Date Oct. 19, 1992 PCT Filed Apr. 17, 1991 PCT Pub. No. WO91/16169 PCT Pub. Date Oct. 31, 1991.The present invention discloses a method of controlling torch height in plasma cutting arranged to monitor the cutting speed so that the optimum torch height is maintained and an excellent cutting quality is obtained even if the cutting speed changes. To this end, a base metal (2) is cut by a plasma arc (3) while a torch (1) is maintained at an optimum height (hc) from the base metal (2), and arc voltage (Vi) is read several times (i=1 to n) after the arc voltage becomes steady, their mean arc voltage (Vb) is calculated, a cutting speed (Fa) is read at the time of steady cutting, the means arc voltage (Vb) is corrected by this cutting speed (Fa) to obtain a target arc voltage (Vc) and the optimum height (hc) is maintained by this target arc voltage (Vc).
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