Method for Handling Focal Length Differences in Marking Various Materials

When laser marking is done, the focus must be adjusted to the material being marked based on its reflectivity, hardness, and other characteristics.The software provides practical solutions for different focal lengths to help users quickly optimize results for commonly used materials like metal, plastic, and wood, and avoid problems such as blurriness and uneven energy distribution that can result from improper focal length.

Why is the focal length so important for different kinds of material?

The focal length of the laser directly affects the size of the beam and the intensity of the light.For example, metal surfaces have strong reflectivity, and if the focal length is not accurate, the energy may be reflected, causing the marking to be blurry. And for light-absorbing materials like plastics, an off focal length can cause burning or shallow markings.In other words, just like taking a photograph, you need to focus the lens before the image will come out clear and steady.

Focal length characteristics of various materials.

Metal (stainless steel, aluminum, etc.

Metal surfaces are smooth and highly reflective, so it is necessary to be especially precise in adjusting the focus.I suggest that you try using a test strip to find the focal point.If the edges of the mark are blurred, the lens may be off by 0.1-0.3 mm.

Plastic and acrylic.

Such materials have strong light-absorbing properties, but are easily warped by heat.If the focal length is too short, the energy will be too high, and it will burn a hole in the surface. If it is too long, the color will not show up.The standard focal length is 5-8 % less than for metal materials, depending on the thickness of the material and the depth of its color.

Wood and leather.

Rough materials can tolerate a greater degree of error in the focal distance, but dark wood may require a lower energy level and a longer focal distance to avoid charring.When marking leather, it is suggested that you first do a small test to find a balance between good visibility and not burning through the leather.

Three steps to adjusting the focus.

The first step is to identify the material.

First, the material properties of the target object must be clearly understood, such as its hardness, reflectivity and heat tolerance.If you are not sure, check the product specifications or consult the supplier.

Second step: Test with a positioning card.

Most marking machines come with a focal length positioning card.A card is placed on the surface of the material to be cut, and the clarity of the laser marking is observed. The height is manually adjusted until the laser spot is the smallest and brightest.

Step 3: Mark each layer.

In the case of special composite materials (such as plastic coated with a metal), it may be possible to try layering the marking.First the surface is treated with a shallow focal length, and then the focal length is gradually increased to prevent an overload of energy all at once.

Solving common problems.

What if the boundaries of the target area are unclear?

Ninety percent of the problems are due to lens misalignment or contamination.First clean the lenses, then recalibrate the focus.If the problem persists, check to see if the galvanometer mirror is out of alignment.

How do you adjust for the varying depth of the water?

Uneven thickness of the material or an uneven platform can cause this.You can add an automatic focusing module or manually adjust the focus in different areas.

Do different colors have different effects?

Dark colors absorb more light, while light colors reflect more.In this situation, don't keep adjusting the focus. Instead, try adjusting the laser power and speed, and then make fine adjustments to the focus.

Finally, it is recommended that you get into the habit of recalibrating the focus after changing lenses.Don't be lazy, it will save you time in the long run!