The operation of a CNC laser cutter is a non-contact manufacturing process that uses high-heat energy from a laser beam to precisely cut, melt, or burn apart materials, all controlled by a computer numerical control (CNC) system.
The key is to control the movement of the laser beam to follow the pattern designed in the computer program.
1. Working principle of CNC laser cutting machine
Laser Generation:
A high intensity laser beam is generated from a laser source, which comes in several types, such as a CO2 laser (suitable for non-metallic and thin metals) or a fiber laser (suitable for cutting thick metals and requiring high speeds).
The principle is to stimulate molecules in a medium (gas or optical fiber) to emit photons as beams of light of a specific wavelength and high energy.
Beam Delivery and Focusing:
The light beam emitted from the source is transmitted through a system of mirrors and/or fiber optic cables to the laser cutting head.
Inside the cutting head is a focusing lens that compresses the large laser beam into a tiny spot just a fraction of a millimeter in diameter, concentrating the heat energy to a high enough concentration to cut the material.
Thermal Cutting:
When a high intensity laser beam strikes a material surface, the material in that area is rapidly heated, causing it to melt , burn or vaporize immediately.
Using Assist Gas:
The laser cutting head has a nozzle that releases assist gas along with the laser beam.
This gas can be oxygen (Oxygen - for cutting thin metals), nitrogen (Nitrogen - for cutting high-quality or stainless steel metals) or compressed air.
The function of gas is:
Blowing out the molten material: Blowing out the cut material from the cutting groove (Kerf).
Lens Protection: Prevents flying debris from damaging the focusing lens.
Promotes reaction: In the case of oxygen, it promotes a chemical reaction with the metal being cut, resulting in faster cutting.
CNC Control (Computer Numerical Control):
The CNC system receives G-code commands and controls the movement of the laser cutting head along the X and Y axes (and the Z axis for focus adjustment or 3D cutting) so that the laser beam moves along a path following the designed geometry.
The system will control other parameters such as laser power, cutting speed, and auxiliary gas pressure to suit the type and thickness of the material.
2. Summary of work procedures
Design: Create a digital file (e.g. .DXF, .DWG) of the desired piece.
Convert Program: Use CAM software to convert design files to G-code.
Setup: Place the material on the worktable and set the cutting parameters on the CNC control panel.
Start cutting: The CNC system commands the source to create a beam and controls the cutting head to move according to the G-code. The beam cuts through the material according to the specified shape.
End: The cut piece will come out of the material sheet with high quality and precise cutting edges.
