| 摘要 |
<P>PROBLEM TO BE SOLVED: To allow maintaining constant the thickness of a material remaining inside an interior cover of a brittle line even in case a thermoplastic resin material having light transmittance is used in a facing layer for decoration of the interior cover and prevent the agnail of the releasing part for air bag deployment from having fine splits by enabling the brittle line to make cleavage in good performance. <P>SOLUTION: According to the brittle line processing method, a first cut-in hole 19b having a small hole 19a for monitoring being open at the surface of the interior cover is subjected to a processing consisting of irradiation with a laser beam produced by a laser beam source 21 until the interior cover 18 is penetrated. The light 221a penetrating from the small hole 19a at this time is sensed by a small hole sensing mechanism 22 to serve for generating a changeover command signal 22a for the laser supplying amount. The supplying amount of the laser beam 2A when a second cut-in hole 19c is processed is set at the laser source 21 so as to be smaller value than at processing of the first cut-in hole 19a by taking in the changeover command signal 22a to a system control part 23. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
