Avoiding Blackening: Material Processing and Laser Parameter Settings

The problem of blackening on gold engravings is a common one. In this article, we will share some practical techniques for preventing this from happening, from two key directions: material handling and parameter settings.The program covers the selection of the right gold, surface pretreatment, and laser power adjustment. It helps users avoid the problem of darkening and improves the quality of the work.

Why does gold micro-carving easily turn black?

The gold micro-sculptures turn black mostly because the material oxidizes or because the parameters of the laser are not set correctly.For instance, gold that is not pure enough is easily oxidized at high temperatures, while too much laser power can burn the metal's surface.To avoid this problem, it's necessary to work on two fronts: preparation of the materials and fine-tuning of the parameters.

The key to processing materials.

Choose the highest purity gold.

The purer the gold (such as 999 pure gold), the stronger its anti-oxidation capability.If the material contains many impurities, black spots are more likely to appear after carving.When buying, try to choose a reputable dealer.

Don't cut corners on surface preparation.

Before carving, the surface is cleaned thoroughly with an ultrasonic cleaner to remove oil and oxidation. This step reduces the amount of residue left by the laser.If you don't have a lens cleaner, you can use a soft cloth moistened with alcohol, but the effect will be less than ideal.

Laser parameter adjustment techniques.

Do not turn the power too high.

Gold conducts heat quickly, so if the power is too high it will burn the surface.It is recommended that you start testing at a low power setting. For example, you can start with a 30 % setting on a 20W fiber laser, and then adjust the power gradually according to the engraving effect until you find the lowest setting at which you can still get a clear image.

Frequency and speed must be in harmony.

The combination of high frequency and slow movement can lead to an accumulation of heat.You can try setting the frequency to 20-50kHz, and at the same time increase the speed of the laser head's movement. This way, you can ensure the depth of the carving while avoiding the problem of local overheating and blackening.

Assist gases cannot be spared.

When carving, nitrogen or argon gas can be used to prevent oxidation.If the equipment doesn't support gas-assisted cutting, at least compressed air can be used to blow the cutting area, reducing the oxidation reaction.

Tips for daily maintenance.

After the carving is finished, use a soft brush to clean away the wood chips, to avoid scratching the surface with hard objects.When stored for long periods, they should be coated with a thin layer of anti-oxidization oil and kept in a dry environment.If it has started to turn black, it can be polished back to its original luster with a jadeite knife.

Remember, adjusting the materials and parameters is like adjusting the heat when cooking, and you will have to experiment several times to find the "golden combination" for your own equipment.If you encounter a problem, don't rush to conclusions. Check each of these two directions in turn, and you'll quickly find a solution.