Patent ID: 6316743
Filing Date: 2001-11-13
Classification: B23K

Abstract:
A laser-cutting method comprising:piercing a cut work by supplying simultaneously a laser beam, a high purity oxygen gas, and a low concentration oxygen gas to said cut work from a laser processing nozzle provided with an inner gas nozzle and an annular-outer gas nozzle surrounding said inner gas nozzle; andcutting said cut work pierced by means of said laser beam by moving said laser processing nozzle with respect to said cut work in a direction parallel to the cut work, while supplying simultaneously said laser beam, said high purity oxygen gas, and said low concentration oxygen gas to said cut work from said laser processing nozzle,wherein said laser beam is supplied to said cut work from said inner gas nozzle, said high purity oxygen gas is supplied from said inner gas nozzle coaxially with the laser beam to said cut work, said low concentration oxygen gas comprises nitrogen gas, air, or a mixture thereof as major components and is supplied from said outer gas nozzle to said cut work in a direction inclined toward a center of said laser beam, and a focal position of said laser beam during piercing is set at a position deeper from the surface of said cut work than that during cutting.