Laser marking, as a high-precision and non-contact modern processing technology, has been widely applied in numerous fields such as metal processing, electronic chips, plastic products, and medical devices. It is renowned for its permanence, high definition and environmental friendliness. However, many users may overlook a key factor: environmental conditions. Laser marking is not carried out in a vacuum. Even the slightest changes in the surrounding environment can act like an "invisible hand", profoundly influencing the final marking effect, equipment lifespan and processing stability.
This article will systematically analyze how environmental factors such as temperature, humidity, cleanliness, vibration and power supply affect the laser marking process, and provide corresponding solutions.
I. Temperature: The Cornerstone of Thermal Stability
The laser itself is a heat source, and its working state is extremely sensitive to the ambient temperature.
Impact on lasers: Most fiber lasers and CO2 lasers have an optimal operating temperature range (typically between 15°C and 25°C). Excessively high ambient temperature can increase the load on the internal cooling system of the laser, reduce the cooling efficiency, and may cause power attenuation of the laser, deterioration of the output beam quality (mode degradation), and even trigger overheat protection and shut down. If the temperature is too low, it may cause the cooling water to freeze (for water-cooled equipment), damaging precision components.
Impact on optical components: Severe temperature fluctuations can cause thermal expansion and contraction of optical components such as focusing lenses and galvanometers. This will alter the curvature and relative position of the lens, leading to focal length drift and spot distortion. It is manifested as thickened marking lines, uneven depth and distorted overall patterns.
Impact on materials: Different materials have different thermal responses to lasers. The ambient temperature will change the initial temperature of the workpiece, thereby affecting its efficiency in absorbing laser energy. For instance, in cold environments, metal workpieces may require higher laser power to achieve the same marking depth, which increases the uncertainty of the process.
Solution
Install the equipment in a temperature-controlled workshop equipped with air conditioning.
Ensure that the laser cooling system (air-cooled or water-cooled) is working properly and maintain it regularly.
Before processing, let the equipment preheat for a period of time to reach a thermally stable state.
Ii. Humidity: Hidden threats of corrosion and condensation
The humidity in the air, especially high humidity, is the "invisible killer" of laser equipment.
Condensation risk: When the ambient temperature is lower than the dew point temperature, water vapor in the air will condense into water droplets on cold metal surfaces. Once condensation water forms in the laser cavity, on the surface of optical lenses, or even inside the laser output head, the consequences can be disastrous. When the lens gets wet, it will heat up rapidly when the laser passes through, causing the coating on the lens to crack and the lens to shatter. Condensate water can also cause rust on metal parts and short circuits in circuits.
Impact on materials: Some materials (such as wood and certain plastics) themselves can absorb moisture from the air. When damp workpieces are exposed to laser burning, uneven vaporization will occur, causing the marking color to turn yellow or black (with intensified carbonization), or resulting in a blurred "water halo" effect at the edges.
Solution
Strictly control the humidity in the workshop. The ideal relative humidity should be maintained between 40% and 60%. An industrial dehumidifier can be equipped.
When the equipment is not powered on, keep the temperature in the machine room 2-3°C higher than the ambient temperature to prevent condensation.
For hygroscopic materials, drying treatment should be carried out before processing.
Iii. Cleanliness: The "Natural Enemy" of Optical Paths
The laser marking machine is a precision device integrating optics, mechanics and electronics. Any tiny contamination will block or scatter the light path.
Dust pollution: Metal powder, plastic debris, common dust and other substances floating in the air will adhere to the protective lenses, focusing lenses and galvanometer mirrors of the laser.
Energy loss: Stains can block and scatter laser energy, resulting in insufficient effective energy received by the workpiece, causing the marking to become shallower or even impossible to mark.
Optical damage: Contaminants on the lens will absorb laser energy and generate heat, creating local high-temperature points that permanently burn the lens coating and substrate.
Precision decline: Dust that settles on the guide rails and lead screws will accelerate mechanical wear and affect the motion accuracy.
Chemical pollution: Corrosive gases (such as acid mists and salt mists) present in certain processing environments will slowly corrode the exposed metals and optical components of equipment, shortening their service life.
Solution
Establish an independent and clean marking workshop, isolated from dust-generating processes such as stamping and cutting.
Clean the optical lenses regularly (depending on the working hours or as needed) with anhydrous ethanol and lens paper.
Equip the equipment with protective covers and close the protective doors when it is in operation.
Iv. Vibration and Airflow: Disruptors of Stability
Laser marking relies on an extremely precise optical path system, and any tiny vibration is its archenemy.
Vibration impact: If the equipment is installed near a punch press, CNC machine tool, or large fan, the vibration from the ground will be transmitted to the marking machine body. This will cause the optical path to shift and the galvanometer to shake, which is manifested as double images, burrs, and incoherent lines in the marking pattern. Working in a vibrating environment for a long time will seriously damage the accuracy of the galvanometer motor and bearings.
Airflow influence: Strong air flow (such as direct fan blowing, air flow from doors and Windows) can interfere with the exhaust path of smoke and dust generated during the marking process, which may cause these contaminants to reattach to the surface of the workpiece, contaminate the marking area, and result in an uneven marking effect. At the same time, the airflow will also cause slight disturbances to the optical path.
Solution
Install shock-absorbing pads for the equipment or place it on a solid and stable workbench.
Keep the equipment away from large vibration sources.
Avoid having the air outlet of the air conditioner or fan blow directly at the light path and processing area.
V. Electric Power Supply: The Source of Energy
Stable and pure power supply is the prerequisite for the stable output of a laser.
Voltage fluctuation: Both excessively high and low voltages can affect the working state of the laser power supply, leading to unstable output power and uneven marking depth. Severe voltage fluctuations can even burn out power modules or control board cards.
Surge and interference: Surge currents in the power grid and electromagnetic interference from other high-power equipment may cause the marking machine control system to freeze or malfunction, resulting in processing interruption or defective products.
Solution
Equip the laser marking machine with a voltage stabilizer and an uninterruptible power supply (UPS) to filter out grid interference and provide power-off protection.
Make sure the equipment is well grounded.
The influence of environmental factors on laser marking is comprehensive and systematic. To achieve stable, efficient and high-quality laser marking production, one must not merely focus on equipment and process parameters.