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Since care is taken to control the amount and distribution of additives to the base iron, most alloy steels are considered ideal candidates for the laser cutting process. High strength materials such as AISI-SAE 4130 (chrome moly steel) and 4340 (chrome nickel moly steel) display exceptional laser cut edges that are square and clean.
Due to its high thermal conductivity and high reflectivity to a CO2 laser's wavelength, aluminum requires high laser energy intensity in order to initiate cutting. This means the need for a laser possessing exceptional beam quality and capable of outputting peak powers of at least 500 watts, in addition to precise focus control. During the cutting process, the assist gas serves primarily to blow the molten material from the cut zone. This helps to produce edge quality that is generally superior to that produced by a bandsaw.
Brass can absorb some energy from the CO2 laser, and essentially behaves like aluminum.
Conventional steels of up to 16 mm lend themselves well to oxygen assisted laser cutting. The kerfs are narrow (as little as 0. 1 mm for thin material) and the resultant heat affected zones are negligible, particularly for mild and low carbon steel. At the same time, the cut edges are smooth, clean, and square.
Lasers have been shown to be viable cutting tools for the fabrication of sheet metal components made from stainless. The controlled heat input of the laser beam serves to minimize the HAZ along the cut edge, thereby helping the material to maintain its corrosion resistance. Since stainless does not react with an oxygen-assist as efficiently as mild steel, cutting speeds for stainless are slightly slower than those for comparable thicknesses of plain steel. At the expense of up to 50% of the speed for oxygen assisted cutting, an inert assist gas can be employed to obtain a "weld ready", oxide-free cut edge.
As for the resultant cut quality, martensitic and ferritic (400 series) stainlesses provide clean smooth edges.
Pure titanium responds well to the concentrated heat energy of a focused laser beam. The use of an oxygen assist enhances the cutting speeds but tends to promote a larger oxide layer along the cut edge. Aircraft alloys such 6AL-4V do tend to exhibit some slag that adheres to the bottom side of the cut but is relatively easy to remove.
Similar in many ways to alloy steels, most tool steels respond well to the cutting action of a laser.
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