A Guide to Laser Marking of Stainless Steel

It provides practical parameters for laser marking on stainless steel, covering optimization of core parameters such as laser power, frequency, and speed to help solve problems such as uneven oxidation and color that is too light.Through concrete examples and analysis of common mistakes, it can be used to achieve more efficient operation and more stable results.

Why is it so important to get the parameters right?

In a nutshell, the laser heats the metal surface to a high temperature, causing it to oxidize and change color.But if the parameters are not correctly adjusted, the colors will be too gray and not dark enough, or they will burn out the screen.When old hands get into trouble, it's usually because they haven't properly balanced the three elements of power, speed and frequency.Below, we'll look at how to get the most out of the current situation.

Preparation: Don't be in a hurry to get started.

The surface of the material must be clean.

When the oil or fingerprints are heated, they become carbonized, and the result is a pattern of spots.After wiping with alcohol, wipe with a dust-free cloth. Don't be lazy.

Choose the right type of laser.

The results of fiber laser marking are more stable than CO2 marking, especially for common stainless steels such as 304 and 316.If you've only got a CO2 machine, remember to turn the power up about 10 % higher.

Core parameter setting techniques.

More power isn't always better.

With a 20-W laser, it's safest to operate at 70-80 % of its rated power.If the power is too high, the thin metal will burn through, but if it is below 60 %, the metal will not oxidize enough, and the color will come out yellow.

The speed and frequency of the punches must be coordinated.

It is recommended that the speed be controlled at 800-1200mm / s, with a frequency of 20-50kHz.For example, to treat a 1mm thick 304 plate, the laser should be set at 80 % power, 1000 mm / s speed, and 30 kHz frequency.

The density of the filling depends on the need.

A gap of 0.05 millimeters is enough for ordinary text, but for the fine patterns of a QR code it needs to be reduced to 0.02 millimeters.But if the spacing is too small, the boards will overheat and warp.

A Guide to Common Problems.

What do you do if the color is gray, not black?

First, check the focal distance. A deviation of 0.5 millimeters can make a big difference in the quality of the print.When the speed was reduced by 200 mm / s and the frequency raised by 5 kHz, the result was immediate.

The edges are rough.

Eighty percent of the time, it's because the pressure of the air isn't enough, and the slag doesn't get blown away in time.Just adjust the air pressure to between 0.3 and 0.5 MPa and you'll be fine.If this doesn't work, the lens may need cleaning.

Tips for care and maintenance

After the workpiece has been fired, do not touch it directly with your hands. The sweat in your hands can cause the remaining oxides to change color.It is recommended that you wash the product once with a neutral detergent, dry it, and then package it.Using a cotton swab dipped in alcohol to clean the laser lens before leaving work every day can extend the life of the lens by another six months.