| 摘要 |
<P>PROBLEM TO BE SOLVED: To carry out an efficient perforating operation without attaching a ground powder in a mud form around a perforated part, even if the perforation is carried out to a target by a perforating apparatus which forms a ground powder expressing a wettability with water while supplying a cooling liquid. <P>SOLUTION: The perforation is carried out on an outer wall 1 which forms a ground powder expressing the wettability with water using a perforating apparatus 20, while a hydrofluoroether is supplied. Preferably, the hydrofluoroether is at least one selected from methyl nonafluorobutyl ether (C<SB>4</SB>F<SB>9</SB>OCH<SB>3</SB>) and ethyl nonafluorobutyl ether (C<SB>4</SB>F<SB>9</SB>OC<SB>2</SB>H<SB>5</SB>). Further, the hydrofluoroether is preferably methyl tridecafluorohexyl ether (C<SB>6</SB>F<SB>13</SB>OCH<SB>3</SB>). <P>COPYRIGHT: (C)2008,JPO&INPIT |
