Abstract A multibeam laser-oxidizer system which optimizes the cutting performance of a laser cutting tool. Two laser beam systems of different focal length are focused on substantially the same area of the material to be cut. The beam of shortest focal length provides a preheat zone with the short depth of focus and small spot size (compared to the second beam) serving to bring the material to a temperature such that a jet of oxidizing gas applied to the heated spot gives rise to the initiation of the cut. The long focal length lens system concentrates the radiant energy of the second beam over a large depth of focus compared to the preheat beam and as a result a uniform cut through a substantial thickness of material is achieved. Details of the lens systems and cutting toolhead are provided together with details of gas flow openings in the cutting tool for supplying both oxidizing and inert shield gases to the cutting area.
A system as defined in claim 1 including means supporting said lens systems for simultaneous movement relative to a workpiece and maintaining said lens systems fixed relative to each other.
Claim 2
Dependent Claim
15 words
The system of claim 1 including means directing a flow of gas onto said area.
Claim 3
Dependent Claim
46 words
The system of claim 1 wherein at least one of said head means includes gas jet means having a gas discharge opening aligned with the associated beam with the beam passing therethrough and operative to direct pressurized gas onto the area where said beam is focused.
Claim 4
Dependent Claim
45 words
The system of claim 1 wherein each of said first and second head means includes gas jet means having a gas discharge opening aligned with the associated beam and each is operative to direct pressurized gas onto the area where the associated beam is focused.
Claim 5
Dependent Claim
23 words
A system as defined in claim 4, wherein said one head means includes a piece of germanium having said discharge opening provided therein.
Claim 6
Independent Claim
86 words
A method of cutting material comprising the steps of focusing a first laser beam on a first spot which is substantially on the surface of the material using a lens system having a first focal length, and focusing a second laser beam at substantially the same time on a second portion of the material which is beneath the surface of the material and substantially in line with said first spot using a lens system having a focal length which is greater than said first focal length.
Claim 7
Dependent Claim
24 words
The method of claim 7 including the step of applying a noninert gas to the focal area of at least one of said beams.
Claim 8
Dependent Claim
19 words
The method of claim 8 including the step of maintaining a column of inert gas about the noninert gas.
Claim 9
Dependent Claim
24 words
The method of claim 7 including the step of applying an inert gas to the kerf of the material as the cutting action occurs.
Claim 10
Dependent Claim
28 words
The method of claim 7 including the step of applying oxygen to the said first area along a path substantially parallel to the path of said first beam.
Claim 11
Dependent Claim
29 words
The method of claim 11 including the step of applying oxygen to said second portion of material along a path substantially parallel to the path of said second beam.