Laser cutting machines can be dangerous if malfunctions occur during operation; novices must undergo professional training before operating them independently. Based on experience, here are 13 key safety details for operating laser cutting machines:
1. Adhere to general safety operating procedures for cutting machines. Start the laser strictly according to the prescribed startup sequence.
2. Operators must be trained and familiar with the equipment's structure and performance, as well as the operating system.
3. Wear required personal protective equipment; protective eyewear meeting safety standards must be worn when near the laser beam.
4. Do not process a material without first verifying whether it is safe for laser irradiation or heating, to avoid potential hazards from smoke or vapors.
5. Operators must not leave their posts without authorization or entrust the machine to others while it is running; if leaving is necessary, shut down the machine or cut off the power supply.
6. Keep a fire extinguisher within easy reach; turn off the laser or close the shutter when not processing; do not place paper, cloth, or other flammable materials near an unprotected laser beam.
7. If any abnormality is detected during processing, stop the machine immediately and either troubleshoot the issue or report it to a supervisor.
8. Keep the laser unit, machine bed, and surrounding area clean, tidy, and free of oil; stack workpieces, sheets, and scrap materials according to regulations.
9. When using gas cylinders, avoid crushing welding cables to prevent electrical leakage accidents. Follow regulations regarding the use and transport of gas cylinders; do not expose cylinders to direct sunlight or place them near heat sources. When opening the cylinder valve, the operator must stand to the side of the valve outlet.
10. Observe high-voltage safety regulations during maintenance. Perform maintenance according to prescribed procedures and schedules (e.g., every 40 hours or weekly; every 1,000 hours or every six months).
11. After startup, manually move the machine along the X and Y axes at low speed to check for any abnormalities.
12. After inputting a new program for a workpiece, run a test cycle first to verify its operation.
13. Monitor the machine's operation during work to prevent it from moving beyond its effective travel range or colliding with other equipment.
Polarization properties of the laser beam. Like the propagation of any electromagnetic wave, a laser beam consists of mutually perpendicular electric and magnetic vectors, both of which are orthogonal to the direction of propagation. The direction of the electric vector is generally considered the polarization direction of the beam. The polarization characteristics of the beam influence how the material absorbs the beam's energy. Cutting parallel to the polarization direction yields a narrow kerf with smooth, straight edges. If the cutting direction forms an angle with the polarization plane, energy absorption decreases, cutting speed slows, the kerf widens, and the edges become rough and non-perpendicular to the material surface. When the cutting direction is perpendicular to the polarization direction, the edges are not rough, but the cutting speed is even slower, the kerf is wider, and the overall cutting quality drops significantly. Although this alignment is theoretically ideal, maintaining parallelism between the cutting direction and the polarization direction during multi-axis motion is difficult to achieve. A phase retarder is employed to overcome this instability. Research indicates that circularly polarized light is best suited for cutting metal. Most lasers produce linearly polarized light at a 45-degree angle to the vertical; the phase retarder converts this into circularly polarized light. While effective for metals, this method is not suitable for materials such as plastics and wood.
Assist gas selection and pressure settings: For high-speed cutting of thin sheet materials, typical pressures range from 150 to 300 kPa, whereas cutting 12 mm thick iron plate usually requires only 40 to 60 kPa.
Cutting speed: If the speed is too slow, the plume of sparks flows directly downward; if too fast, the plume forms an unstable acute angle with the vertical. An obtuse angle between the spark plume and the vertical indicates an appropriate speed.
Gas pressure setting: Assist gas pressure is controlled by the CNC system. Proper procedure requires calibrating the gas pressure controller: select "automatic mode" and activate the calibration program. After activating the program, press the cycle start button and follow the on-screen prompts; the system will then automatically calibrate the gas pressure mechanism.
