Laser Marking on Metal Sheets

Metal plates are easily deformed by the high temperatures generated during laser marking.Sharing practical techniques for avoiding distortion, such as optimizing laser parameters, controlling heat dissipation, and fixture design, it helps users improve processing quality and reduce material loss.

Why is it that thin metal plates deform so easily when marked?

The low thermal capacity of the metal foil causes local temperature to rise rapidly when laser marking is applied, resulting in uneven thermal expansion of the material.If the heat isn't dissipated in a timely manner, or if the parameters of the equipment are not set correctly, the result is almost always a misshapen product.And with fast-conducting materials like stainless steel or aluminum, the slightest mistake can ruin the whole product.

Key skill 1: Optimizing laser marking parameters.

Power and speed must be matched.

Too much power can cause "burnout," so it is recommended that you start with a lower power (such as 20 watts), and gradually raise it.If the speed is too fast, the markings may not be clear, and if it is too slow, heat may build up. A speed between 500 and 800 mm / s is the most stable.

Tune the dial to the right frequency.

Although high frequency is more efficient, heat accumulates quickly.When marking thin plates, the frequency should be set to 20-50kHz for safety, to ensure clarity and disperse the heat.

The second key technique is to improve heat dissipation.

Don't be lazy when it comes to the breathing exercises.

The cooling effect can be speeded up by blowing compressed air or nitrogen onto the area being marked.The air pressure should not be too high, 0.2-0.5MPa is sufficient. The key point is that the entire surface to be processed must be covered evenly.

The back of the chip is attached to a heat-conducting material.

A heat-conducting silicon pad or aluminum plate can be attached to the back of a thin plate to speed the dissipation of heat.This technique can reduce the probability of deformation by more than 50 % for small pieces.

Thirdly, the design of the fixture is critical.

It's safer to hold with several points than with just one.

The press uses a modular fixture with springs to apply equal pressure around the edges of the plate.Don't use screws to fasten it down, or when you heat it to imprint the letters, it will expand and warp.

Leave room for expansion.

Clamps should not hold the metal sheet too tightly, but leave a 0.5-1 mm gap around the edge. This allows the material to expand when heated and contract when cooled, which minimizes distortion.

A little trick for daily use.

Before processing, the boards should be left on the workbench for one hour to allow them to reach room temperature.Don't remove the piece right after stamping, wait two or three minutes before removing the clamp.If the material is especially thin (less than 0.3 mm), it's better to engrave it in several shallow passes, which takes a little more time but helps maintain the flatness of the board.

Remember, for different materials you will need to make flexible adjustments to your plan.For example, copper plates cool quickly and so can be used at a higher power level, while titanium plates are easily oxidized and must be used with an inert gas.With a little trial and error, you can find the best configuration for your own machine.