Laser Parameters for Biocompatibility

In the medical device marking scenario, he shares how to ensure that the marking results pass biocompatibility testing by adjusting laser parameters (such as power, frequency, and speed).This covers material compatibility, parameter optimization, and test verification methods, helping users avoid the risk of test failure resulting from improper parameters and raising the compliance of medical products.

How do laser parameters affect biocompatibility?

Many people think that biocompatibility testing is only related to the material itself, but the actual parameters of the laser marking process also have a direct impact on results.For instance, if the power is too high, the surface of the material may carbonize, leaving behind too many impurities. If the speed is too slow, excessive heat may be generated, altering the microstructure of the material.These are the kind of problems that can cause an inspection agency to give a company a failing grade.

Key parameter setting techniques.

The principle of matching materials to wavelength.

Common medical materials like stainless steel and titanium alloys respond better to fiber lasers (1064nm).And for high-molecular materials like PEEK, the use of ultraviolet lasers (355nm) can reduce thermal damage.Choosing the wrong wavelength is like trying to make tea with cold water-the results are greatly diminished.

The balance of power and speed.

Don't blindly pursue high power! Medical stainless steel is best started with 20W, and the speed should be controlled at 800-1200mm / s.You can first test the combination on some waste material. If the colors are clear and the paper doesn't turn black, it's a good combination.Remember, the parameters have to be just right.

The hidden relationship between frequency and pulse width.

High frequencies (such as 50kHz) are best for fine text, while lower frequencies (below 20kHz) are better for deep carving.But when the frequency is increased, the pulse width must be shortened at the same time to avoid the buildup of heat.This combination is like the rhythm of a dance, and if it is not in step, the dancer will be marked down.

A checklist for self-examination before the test.

Surface residue test.

If the cotton swab turns black, it means that the area is severely carbonized.In this case, the power has to be reduced or the scanning speed increased.

Edge sharpness test.

If the edges of the markings look like they were drawn with a brush, then they probably weren't focused or the shutter speed was too slow.Often, simply readjusting the focus can solve the problem.

This accelerates aging verification.

The samples were put into normal saline for 72 hours and then dried and examined to see if the labels had come off.This method can detect adhesion problems earlier, and is better than sending the product to a testing agency and having it sent back.

Common pitfalls.

Last week one of our clients told us that their titanium alloy bone plates always failed the test.Finally, they discovered that by using a stainless steel mold, they could increase the power output by 15 %.The color of the labels was changed from dark gray to light gray, and the problem was solved.So it's important to remember that there's no "one-size-fits-all" parameter template.

If you want to pass the inspection smoothly, the key is to make many test samples.He suggests that when you change materials, you should have at least five parameter combinations to compare.Although it's a little more troublesome in the beginning, it's much more cost-effective in the long run.