Preparations Before Processing
Whether the preparations before processing are in place directly affects the accuracy and efficiency of laser cutting section steel. First of all, a comprehensive inspection of the section steel is required, and the inspection focus varies for different types of section steel.
For H-beams, it is necessary to check the perpendicularity between the flange plate and the web, and whether there are deformations or protrusions at the welding joints. If there are protrusions, they will cause the laser focus to shift during cutting, affecting the cutting quality. For angle steel, attention should be paid to the right-angle accuracy of its two sides. If there is bending, it must be straightened first; otherwise, the size of the cut workpiece will be deviated. For channel steel, it is necessary to check for impurities or rust inside the groove. Impurities in the groove will block the normal irradiation of the laser beam, and rust will affect the reflection and absorption of the laser, reducing cutting efficiency.
Secondly, the method of cleaning impurities on the surface of section steel should be adjusted according to the type of section steel. Oil stains and dust are easy to accumulate at the angle between the flange plate and the web of H-beams, which can be cleaned with a high-pressure air gun combined with a brush; the corner gaps of angle steel can be cleaned with a thin steel wire brush; rust inside the groove of channel steel can be removed by sandpaper grinding to ensure that the surface cleanliness meets the requirements of laser cutting.
In addition, the selection and adjustment of fixtures should be adapted to the shape of the section steel. When fixing H-beams, fixtures matching the width of the flange plate should be used to prevent the flange plate from deforming due to vibration during cutting; angle steel can be fixed with V-shaped fixtures to ensure that both sides are stably fixed; channel steel needs support blocks in the groove to avoid deformation of the groove during cutting. At the same time, laser parameters should be set accurately according to the material and thickness of the section steel.
Operating Specifications During Processing
The standard operation during processing is the core link to ensure cutting quality, and the cutting operations of different section steels must follow corresponding skills.
When cutting H-beams, due to their H-shaped cross-section, attention should be paid to keeping the distance between the laser head and the surface of the flange plate consistent when cutting holes or grooves on the flange plate. For example, when cutting a circular hole on the flange plate of an H-beam, the movement trajectory of the laser head should be set in advance in the programming to ensure that the focus is always at the optimal position when cutting around the hole. When cutting the web of an H-beam, if the web thickness is thin (such as 6mm or less), the cutting speed can be appropriately increased to reduce heat input and avoid thermal deformation of the web.
For angle steel, whose two sides form a right angle, the cutting path must be accurately calculated when cutting bevels or oblique angles. For instance, when cutting a 45° diagonal line on angle steel that forms 45° with both sides, the angle parameters must be accurately input into the numerical control system, and the cutting angle of the laser head should be adjusted to ensure the smoothness of the diagonal line. When cutting the end of angle steel, attention should be paid to the perpendicularity between the end and the side, and parameters can be calibrated by trial cutting a small section before formal cutting.
The key to cutting channel steel lies in the processing of the groove. When cutting holes in the groove of channel steel, it is necessary to ensure that the laser beam can vertically irradiate the center of the hole. Due to the limited space in the groove, a short-focus laser lens should be selected to reduce the reflection interference of the laser beam in the groove. When cutting the flange plate of channel steel, if a long strip incision needs to be cut, the stability of the cutting speed should be controlled to avoid serrated edges caused by speed fluctuations.In addition, parameters should be adjusted in real time according to the thickness of the section steel during processing.
Processing After Cutting
Proper processing after cutting can further improve the quality and usability of the cut section steel, and the processing methods vary for different section steels.
After cutting H-beams, burrs and slag may appear on the cutting surfaces of the flange plate and web, especially near the welding joints. An angle grinder should be used for grinding, and attention should be paid to maintaining the flatness of the cutting surface during grinding to avoid dimensional deviations caused by excessive grinding. For the long straight cutting edges of H-beams, a belt sander can be used for polishing to improve surface finish.
The corners of cut angle steel are prone to sharp edges, which need to be blunted with a file to prevent scratches during handling and installation. If the angle steel needs to be spliced after cutting, the flatness of the cutting surface should be checked. If there is unevenness, it can be corrected by grinding to ensure tight fitting at the splicing position.
Cleaning the cutting surface inside the groove of channel steel is more difficult. A small hand-held grinder can be used to grind inside the groove to remove slag and burrs. For special-shaped cutting parts of channel steel, such as curved cutting surfaces, fine sandpaper should be used for manual grinding to ensure the smoothness of the curve.
In terms of quality inspection, for H-beams, the length, width, and perpendicularity between the flange plate and the web after cutting should be checked to see if they meet the design requirements; for angle steel, the length of the right-angle sides and angle deviations should be measured; for channel steel, the size of the groove and the flatness of the cutting surface should be inspected. If the cutting size is out of tolerance, H-beams and channel steel can be adjusted by slight straightening, while angle steel can be corrected by supplementary cutting.
Safety and Maintenance Matters
In the process of laser cutting section steel, safe operation and equipment maintenance are important prerequisites to ensure smooth production. Safety and maintenance measures should be adjusted according to the processing characteristics of different section steels.
When processing H-beams, due to their large volume and weight, cranes or forklifts should be used during handling. Operators must stand at a safe distance to avoid injury caused by the collapse of the section steel. Cutting H-beams produces a lot of smoke and dust, especially when cutting thick-walled H-beams. The ventilation system must be fully operational, and a local exhaust hood can be installed above the cutting area if necessary.
When cutting angle steel and channel steel, operators must wear laser protective goggles, because these two types of section steel have relatively high reflectivity, and laser reflection may cause damage to the eyes. At the same time, angle steel and channel steel should be stacked neatly to avoid collapse due to excessive stacking, and should be handled with care during use to prevent collision and deformation.
In terms of equipment maintenance, cleaning should be carried out according to the characteristics of the slag generated by cutting different section steels. The slag generated by cutting H-beams is relatively large and easy to accumulate on the workbench, so it needs to be cleaned once a day; the slag generated by cutting angle steel and channel steel is relatively fine, so the slag collection box of the laser cutting machine should be cleaned regularly to prevent the slag from blocking the slag discharge channel.
The wear of the laser head should be checked regularly. The laser head wears faster when cutting thick-walled H-beams, and it is recommended to check it every 500 meters of cutting; when cutting thin-walled angle steel and channel steel, it can be checked every 1000 meters of cutting. In addition, the cooling system of the laser generator should be regularly replaced with coolant, especially when continuously cutting large section steels such as H-beams, the replacement cycle of the coolant should be appropriately shortened to ensure that the equipment is in good operating condition.
--Rayther Laser Jack Sun--