All laser cutting machines essentially consist of a laser, a light guidance system, a numerical motion control system, an automatically adjusting cutting head, a work platform and high-pressure gas blowing systems.
Many parameters can affect the laser cutting process, some depending on the technical performance of the laser and machine tools, while others need to be adjusted based on specific needs.
Main adjustments for laser cutters:
Beam Mode
The fundamental mode, also known as Gaussian mode, is the most ideal for cutting and is mainly found in low-power laser cutting machines with power less than 1 kW. Multimode is a combination of higher order modes, which has weaker focusing and cutting capabilities compared to single-mode lasers.
Laser power
The laser power required for a cutting machine depends on the cutting material, material thickness and cutting speed requirements. Laser power has a significant impact on cutting thickness, cutting speed and cutting width. Generally, as laser power increases, cutting capacity for thicker materials also increases, resulting in faster cutting speeds and wider cuts.
Focal point position
The position of the focal point greatly affects the width of the cut. Generally, positioning the focal point about 1/3 of the material thickness below the surface results in the deepest cut and narrowest cutting width.
Focal length
When cutting thick steel sheets, a longer focal length beam should be used to obtain a good quality vertical cutting surface. A greater focal depth increases the beam spot diameter, reducing power density and cutoff speed. To maintain a certain cutting speed, the laser power must be increased.
For cutting thin sheet metal, a beam with a shorter focal length is preferred as it results in a smaller beam spot diameter, higher power density and faster cutting speeds.
Auxiliary gas
Oxygen is commonly used as a cutting gas for low carbon steel to promote the heat of the iron-oxygen combustion reaction during the cutting process, which results in faster cutting speeds and better cut quality, producing slag-free cuts. .
Increased pressure leads to greater kinetic energy and improved slag removal capacity. The cutting gas pressure should be determined based on the factors of material, thickness, cutting speed and surface quality.
Nozzle structure
The structure and nozzle size of the laser cutting machine also affect the cutting quality and efficiency. Different nozzles should be used for different cutting requirements. Common nozzle shapes include cylindrical and conical shapes.
Coaxial gas blowing (where the gas flow is concentric with the optical axis) is generally used for laser cutting. If the gas flow is off axis, excessive spatter may occur during cutting.
To ensure the stability of the cutting process, the distance between the nozzle end and the workpiece surface must be controlled, normally between 0.5 and 2.0 mm, for smooth cutting.
