Uneven Color? How to Fix It in Three Easy Steps

The three-step process covers parameter settings, equipment calibration, and material compatibility, and helps you quickly solve the problem of color variation, thus improving processing quality.This is suitable for laser marking operators and industrial process users.

Why is there always a color difference in color printing?

When many of our friends tried to do colored marking on metals and plastics, they clearly used the same parameters, but the results were inconsistent, with some being lighter and some darker, and sometimes rainbow-colored spots appeared.If you have a problem, don't rush to return your machine for repair. First check to make sure you've got these three key points covered.

Step 1: Adjust the laser's "breathing rhythm.

Finding the balance point between power and frequency.

It's just like cooking: You have to control the heat. The depth of the color is directly related to the power and frequency of the laser.If the power is too high, it will burn the material's surface, while if it is too low, the colors will not come out properly.Start with the base parameters at 80 %, and adjust by 5 % each time, observing the results until the color is even and stable.

Don't let the speed steal the color.

If the marking speed is too fast, it can lead to a local energy deficit. For stainless steel, the speed should be controlled at 800-1200 mm / s, and for aluminum it should be lowered to 600-900 mm / s.In practice, waste material can be used to test the speed gradient, and the color differences in the various speed bands can be seen with the naked eye.

Second, a thorough check-up of the equipment.

The success of the mission depends on how clean the lens is.

Last week we had a case where a customer had fingerprints on a new lens they were using, and this caused the marked area to appear cloudy.Remember: You should use alcohol to clean the focusing lens and the scanning mirror at least once a week. When you clean them, wipe the lens or mirror in only one direction. Don't make circles.

The cooling system is a critical link in the chain.

A change of just 1 ℃ in the temperature of a laser can affect the stability of the wavelength.The focus of the inspection is to check that the water-cooling equipment is flowing at the correct rate, and to make sure that the heat sinks of the air-cooling equipment are not covered with dust.A simple test method: After working continuously for two hours, touch the outside of the machine with the back of your hand. If it is slightly warm, this is normal. If it is hot, then it is time to have it checked out.

Step three: "Negotiate" with the materials.

Different materials require different treatment.

Stainless steel prefers high frequencies (60-80kHz), whereas titanium alloys need a lower frequency of 20-40kHz.A small trick: Punch out a test piece from an unnoticeable area on the material's edge, and while adjusting the parameters, focus on the color difference between the central area and the edge.

Surface treatment is very important.

A difference of 0.1 millimeter in the thickness of the oxide layer can affect the coloring effect.He suggests using a special cleaning agent to remove grease and oil from the surface of the metal before painting, especially the anti-rust coating on machine parts. This small detail can reduce color variation by more than 50 %.

Following these three steps, even the most stubborn color difference problems can be solved.Next time you encounter a case of uneven coloring, remember not to rush in to adjust the parameters. Instead, go back and check the entire process chain. Often you will find something unexpected.