A Guide to Setting up Parameters for Laser Marking on Stainless Steel and Aluminum

The book covers a wide variety of topics, including the parameters of laser marking on stainless steel and aluminum alloy, the adjustment of core parameters such as power, speed, and frequency, the influence of the characteristics of various materials on laser marking, and the solutions to common problems such as blurred or yellowed markings.

A comparison of the characteristics of stainless steel and aluminum alloy.

Although stainless steel and aluminum alloy are both metal materials, the differences in their physical properties directly affect the laser marking effect.Stainless steel is hard and corrosion-resistant, and the layer of oxidation that forms on the surface is relatively thin.Aluminum alloys are softer and more heat conductive, and can easily oxidize when exposed to high heat. If the parameters are not set correctly, the marks can turn gray or the edges will be blurry.

Setting the parameters for laser marking.

Power and speed.

Stainless steel requires higher power (30-50 watts), but the speed can be slowed down to ensure that the laser penetrates the surface oxide layer.Aluminum, on the other hand, is more easily burned and deformed by heat, so it is best to use low to medium power (20-35 watts) and to increase the speed at which the beam is scanned over the workpiece.

Frequency selection.

The higher the frequency, the higher the density of laser points, and the finer the marks.Stainless steel is recommended to use high frequencies of 20-50 kHz, which can produce a clear black and white contrast.Aluminum alloys are more sensitive to frequency, so it is suggested that you test from 10-30kHz, and gradually increase the frequency. If the frequency is too high, it will cause the surface to turn white; if it is too low, it will leave a discontinuous trace.

The number of times the needle is raised and lowered and the distance between stitches are also adjusted.

The surface of stainless steel is extremely smooth, and the gap between the laser beam and the target surface can be set to between 0.02 and 0.05 mm, so that a single pass is usually sufficient.Because aluminum alloy is porous, the gap is reduced to 0.01-0.03mm with one to two additional repetitions.

A few tips on real-life adjustments.

First we made a small sample to test.

Do not rush to start marking the workpiece! Cut a small piece from the scrap, mark it using different parameter combinations, and observe the contrast and edge effects.In particular, if you mark an aluminum alloy and then wipe it with your finger, the mark should not easily rub off. If it does, it indicates that the energy level is too low or the frequency is too low.

Make good use of the breathing gas.

When marking stainless steel, nitrogen gas is used to prevent oxidation and yellowing. When marking aluminum, compressed air is used to cool the material and blow away the molten slag, producing a cleaner mark.The pressure doesn't have to be too large, 0.2-0.5MPa is enough.

Clean the lens regularly.

Marking metal produces dust, which can accumulate on the focusing lens, reducing the energy of the laser beam.After marking the aluminum, it is especially important to remember to wipe the lens with a clean cloth dampened with alcohol to keep the light path stable.

Common problems and emergency solutions.

If the stainless steel marking turns gray, first check to see if the focal point has shifted, then increase the power by 5-10 %.If cracks appear after marking an aluminum alloy, it may be that the speed is too slow or the number of passes is too high. Try lowering the power and raising the scan speed.If all else fails, the simplest solution is to get a materials parameter sheet from the equipment manufacturer and make adjustments accordingly.