Eliminating Burrs and Heavy Dross: Focal Point and Power Matching Guidelines for Thick-Wall Laser Pipe Cutting

In the fields of heavy industrial pipe fabrication, engineering machinery manufacturing, and petroleum pipeline laying, the application of thick-wall tubes (typically referring to metal tubes with wall thicknesses greater than 6 mm) occupies a core position. However, many laser tube cutting machine operators frequently encounter stubborn cutting defects in actual production: severe dross hanging at the bottom of the cut, frequent edge burrs, or even cutting interruptions caused by difficulty in penetration. This not only necessitates extensive manual grinding and secondary processing but also directly drags down the delivery efficiency of the entire production line.

To fundamentally resolve the burrs and dross issues in thick-wall tubes, one must deeply analyze the physical mechanisms of laser energy transmission and slag evacuation:

: Thick-wall tubes possess substantial cross-sectional thickness. As the laser beam penetrates the surface layer, beam energy density gradually attenuates with increasing depth. If the focal point position is improperly set, the bottom metal cannot be completely melted.

: The amount of molten metal generated during thick-wall cutting vastly exceeds that of thin-wall tubes. If auxiliary gas pressure is insufficient or nozzle specifications are mismatched, high-pressure gas fails to completely blow the slag out from the bottom of the deep, narrow kerf, forming stubborn dross upon cooling.

To ensure clean, burr-free, and dross-free cut surfaces on thick-wall tubes, operators must completely abandon universal parameters and adopt targeted, advanced process adaptation strategies:

: When cutting thick-wall metal tubes, cutting speed must be appropriately reduced while laser output power is increased, prolonging the residence time of the laser locally to ensure optical energy fully penetrates the bottom of the tube wall and completely melts the metal.

: Unlike the negative defocus used for thin-wall tubes, processing thick-wall tubes can employ a positive defocus mode, positioning the focus slightly above the tube surface or at an appropriate internal position to widen the kerf width and enhance the circulation and evacuation efficiency of the auxiliary gas.