Solutions to Common Problems in Marking High-Reflective Materials

The company provides practical solutions to the problems of unclear markings, damaged equipment, and difficulties in setting parameters that are commonly encountered when laser marking high-reflectance materials.These include the pre-treatment of materials, the optimization of laser parameters, and the maintenance of equipment. These efforts have helped users solve problems with marking highly reflective materials such as metals and mirrors, and have improved processing efficiency and product quality.

Why is it that high-reflectivity materials always cause problems?

Highly reflective materials like stainless steel, aluminum alloys, or mirror surfaces reflect the laser beam, leading to poor absorption of energy.At this time, the laser may not be able to mark the object, or the mark may be blurry, or it may even damage the laser head.Don't panic. Let's take a look at some of the most common problems and how to deal with them.

Surface treatment is the key.

Cleaning and coating.

The first step is to thoroughly wipe the surface of the material with alcohol to remove any oil or fingerprints.If the surface is still too reflective, try spraying a matte finish over it (such as a special primer for laser engraving), and then engrave again after it has dried.This is especially effective for mirror-polished stainless steel, allowing the laser energy to be more easily absorbed.

A simple technique for surface roughening.

Use fine-grit sandpaper (800 or more), and sand in one direction only. Don't go back and forth! You only need to sand until the surface is uniformly matte.Be careful not to apply too much pressure, so as not to mar the finished product.

A practical guide to laser parameter adjustment.

How much power and how fast?

High power does not necessarily mean good effect. It is recommended that reflective materials be processed at a medium or low power (for example, 30 % of the rated power), and a fast scanning speed (1200mm / s or more).The power level is gradually increased until the markings are clear, but not burnt.

Frequency and defocus adjustment.

The frequency is reduced to below 20 kHz and the intervals between pulses are lengthened, giving the material time to cool down.The amount of defocus is adjusted within a range of ± 0.5 mm; sometimes a positive defocus is needed to achieve the desired effect.

Protecting your equipment.

Installation of anti-glare devices.

One solution is to install a 45-degree angled anti-reflective shield on the laser head, or to use a coaxial vision system to locate the data.Regularly inspect the focusing lens, and if you find any burned spots, replace it immediately. Don't be stingy with a little consumable material.

Cooling must keep up.

If the machine is used for more than 20 minutes continuously, it is suggested that the machine be turned off for 5 minutes to cool down.If possible, install a heat dissipation device, especially in summer when the temperature in the workshop is high. Excessive heat can cause instability in the laser output.

What about the oxide layer?

Some high reflective materials have a natural oxide film on their surfaces, and if the film is not removed, the depth of the marking will be uneven.First, wipe the surface with a 5 % solution of hydrofluoric acid. When done, rinse thoroughly with water.If you don't want to go to the trouble, you can buy special marking materials that have already been pre-oxidized.

By using these methods and following the calibration procedure in the equipment manual, 80 % of the problems with marking high-reflective materials can be solved.The key is to be patient and adjust the parameters one at a time.