In 2025, the laser marking machine is one of the core products of the Suzhou OMA brand. With the growing sales volume and extended service life of a large number of laser marking machines, some customers may encounter the issue of unclear printing. Today, OMA will discuss the specific causes and solutions to this problem with you.
First, before conducting in-depth troubleshooting, please be sure to follow safety procedures: Turn off the equipment power supply and wait until the laser head is completely cooled down before performing inspection and cleaning. This avoids accidental laser injury and burns.
The following are the specific causes of unclear printing in laser marking machines and the corresponding troubleshooting steps:
I. Hardware Issues of the Laser Marking Machine
This is the most direct cause, usually related to optical components.
- Contamination of Focus Lens/Field Lens: This is the most common cause.During the marking process, the laser generates tiny smoke and spatter. These contaminants adhere to the protective lens of the focus lens or the focus lens itself. Common symptoms include overall blurry laser printing, stains, and insufficient energy, leading to thickened, fuzzy lines.The solution is to gently wipe the lens with special lens cleaning paper and anhydrous ethanol. Be sure to use a soft motion to avoid scratching the lens coating.
- Deviation of the Laser Head's Output Optical Path:If the laser equipment is vibrated or impacted, the internal optical path may shift slightly. As a result, the laser does not pass through the central optical path completely, causing energy loss. A common symptom is uneven print depth, with some areas being unclear.In this case, adjustment and calibration by OMA's professional technicians are usually required. Users must not attempt to operate it themselves.
- Power Attenuation or Aging of the Laser:As the laser is used over time, its output power will naturally attenuate. A common symptom is that even when parameters are set to the maximum, the marking remains shallow and blurry, failing to reach the previous depth/contrast.For factory users, it is necessary to contact the manufacturer to test the actual output power of the laser. If necessary, replace the laser.
II. Issues with Marking Materials (Objects to be Marked)
Laser marking is achieved through physical or chemical reactions between the laser and the material surface, so the material itself is crucial.
- Material Mismatch:Different types of lasers (e.g., fiber, CO2, ultraviolet) are suitable for different materials. For example, fiber lasers work well on metals and plastics but poorly on transparent materials and certain polymer materials; CO2 lasers perform well on non-metals (wood, glass, leather).If the laser machine fails to mark at all or only leaves extremely shallow marks, confirm whether the laser type is suitable for the current marking material. For instance, marking transparent plastic or white plastic may require an ultraviolet laser machine.
- Inconsistent Surface Treatment of Materials:If the material surface has oil stains, water stains, uneven coating, or inconsistent oxide layer thickness, the laser marking may be intermittent, with "speckles" or "water ripples," and some areas may be clear while others are not.In this case, clean the material surface with appropriate cleaning agents to ensure the marking area is clean, dry, and uniform. For coated materials, parameters may need to be adjusted to match the coating.
III. Software Parameter Setting Issues of the Laser Machine
Marking parameters are key to controlling the interaction between the laser and the material.
- Low Power Setting:If the laser power is set too low, it will not be sufficient to cause effective changes on the material surface. The common solution is to gradually increase the marking power of the laser machine until the marking becomes clear. Do not increase the power too much at once to avoid damaging the material or lens.
- Excessively Fast Marking Speed:If the production line speed or laser head movement speed is too fast, the laser will have too little time to act on each point, resulting in insufficient energy accumulation and unclear printing. In this case, appropriately reduce the marking speed to allow the laser enough time to interact with the material.
- Inappropriate Frequency Setting:The light source frequency of the laser machine determines the density of laser pulses. Both excessively high and low frequencies may affect the marking effect.If the frequency set inside the machine is too low, it may cause discontinuous dots in the printing; if the frequency is too high, it may lead to excessive energy heating and blurred edges. Adjust the frequency according to the material characteristics: generally, higher frequencies are needed for metal marking, while lower frequencies may be required for non-metals such as plastics.
Finally, if you encounter difficult-to-judge or difficult-to-solve laser machine problems, remember to contact OMA's technical support immediately. Especially if the above steps are ineffective, it may indicate a hardware failure (e.g., laser, optical path), and you should contact the after-sales service of the equipment supplier right away.
