Application of High Power Laser Treatment Technology in the Machine Industry

A laser source is rated by output power and beam quality. In the machine industry, high power usually means a source in the kilowatt class, where the beam can be focused to a spot a few tenths of a millimeter across and still carry enough energy density to melt or vaporize steel. The number on the nameplate is not the whole story. Beam parameter product, focal length and assist gas decide what the spot does once it lands on the plate.

Higher power buys cutting speed on thick plate and deeper keyhole welds. It also raises the heat input into the surrounding metal, which is where distortion and heat-affected zones come from. A 6 kW source cutting 12 mm carbon steel leaves a wider HAZ than a 2 kW source cutting 3 mm, and that difference shows up later at the grinder or the stress-relief oven.

For job shops, the practical question is not which source is strongest. It is which process gives the required edge, kerf and tolerance at a cost that still makes sense against milling or punching. A high power laser is a fast roughing tool for sheet and plate, not a replacement for a machining center when the drawing calls for a bore at ±0.005 mm.

Fiber laser cutting handles mild steel, stainless, aluminium, brass and copper. The cut edge on thin sheet is often good enough to use as-is, with a kerf around 0.1–0.3 mm depending on thickness and nozzle. Nitrogen assist gives a clean, oxide-free edge on stainless; oxygen assist is faster on carbon steel but leaves a lightly oxidized face that usually needs blasting or tumbling before coating.

Thickness is the usual limit. As plate gets thicker, cutting speed drops and the kerf widens, and the edge starts to show dross and a slight taper. At some point the part is cheaper to blank on a waterjet or rough out on a mill. For a bracket that only needs a profile, laser is the fast route. For a plate with a deep pocket and a tight bore pattern, laser blanks the outline and the CNC does the rest.

Hole quality deserves its own check. A laser-cut hole smaller than roughly the material thickness tends to come out tapered and slightly undersized. If the drawing calls for a reamed or threaded hole, cut it undersize on the laser and bring it to size with a drill or boring head. That two-step route is normal in shops that run both processes under one roof.

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  Good fitSheet and plate profiles, brackets, panels, gaskets, thin-walled enclosures.
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  Poor fitHoles below material thickness, deep pockets, faces that need a mirror finish.
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  Assist gasNitrogen for stainless and aluminium; oxygen for faster carbon steel cuts.
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  Edge noteLaser edges carry a small HAZ; heavy weldments may need it machined off.

Laser welding joins thin sections with a narrow bead and low heat input, which keeps distortion down on parts that would pull out of shape under TIG. It works well on exhaust tubing, sensor housings and small bracketry where the joint is close-fitting. The catch is fit-up. A laser weld needs the gap under roughly 0.1 mm, and if the parts do not close, the beam passes through and you get a weak joint with no warning.

Deep-penetration keyhole welding reaches thicker sections in a single pass, but it demands clean surfaces. Oil, oxide or a coating on the faying surface turns into porosity. For production, parts are usually laser-cleaned or wiped right before welding, and fixtures hold the joint closed.

Laser drilling makes small holes in hard or thin material without the burr a twist drill leaves. It suits filter plates, injector orifices and cooling holes. The practical limit is the depth-to-diameter ratio; beyond roughly 10:1 the hole starts to taper and the exit can flare. A recast layer forms on the wall, which matters on parts that see fatigue or corrosion.

Laser hardening is a different mode. The beam sweeps a track across a wear surface and the surface self-quenches as heat drains into the cold core. Case depth is shallow, often a few tenths of a millimeter to a couple of millimeters, so it suits shafts, guides and slideways rather than parts that need through-hardening. The part stays soft underneath, which keeps it tough.

Most real parts use both. A laser blanks the profile and cuts the lightening holes; the machining center then bores the bearing seats, faces the mating surfaces and taps the threads. Doing it this way cuts chip volume and lets the mill spend its time on the features that actually need tolerance.

The handoff point matters. Leave stock on laser-cut edges that will be finish-machined, because the HAZ is slightly harder than the parent metal and can chip a cutter if you take a heavy pass. A light cleanup pass removes it. On parts that will be anodized, laser-cut edges sometimes show a different shade because of that same zone, so it pays to machine or blast them first.

For prototypes, the sequence is usually laser or waterjet blank, then 3-axis or 5-axis machining for the critical features. Once the design settles, the same split carries into production. At GreatLight we run 127 high-precision CNC machines across three wholly-owned plants, including 16 simultaneous 5-axis centers and a Ø400 mm rotary table, so laser-cut blanks can move straight into milling, turning or finishing without a second supplier in the loop. Tolerances hold at ±0.005 mm where the drawing calls for them.