How does laser engraving work

Contents:

Laser markers can not only actually mark but also engrave. In this article we will discuss how exactly this is possible, what kind of conditions there are, and what material and laser source type can process.

Principle of work

So, how do laser engravers work? Let us start with the basics. Laser engravings are created by evaporating or burning material, which means selective layer removal via the transition from solid to gaseous state without heating the liquid or melting phase. Lasers can accomplish this because they concentrate a large quantity of energy into a single little dot.

Depending on the number of passes you set, different depths of engraving can be achieved. However, pay attention that the more depth you want, the more time you have to spend on producing. More on that in the “Deep engraving” module.

All materials have their wavelength absorptivity. And while absorbing enough energy in that range, the workpiece goes from one condition to another. Wattsan has three types of laser sources for markers: CO2, fiber, and ultraviolet, and let’s see which materials can be processed by each.

CO2, fiber, and UV markers

CO2

These markers have a 10640 nm wavelength, and it is absorbed the best by the majority of organic materials—wood and products out of it, leather, textile, etc. Furthermore, it can work with rubber, glass, plastics, stone, ceramics, etc.

Fiber

Here, the wavelength equals 1064 nm, and materials that are sensitive to it are metals; that’s why our managers frequently recommend FL TT, FL Box, or FL compact for those working with aluminum, stainless or carbon steel, brass, titanium, or other metals and alloys. However, depending on the settings, these markers may also process rubber and leather.

In comparison with the CO2 laser marker, the fiber machine has a smaller laser dot diameter that allows it to make more precise and smaller images.

Ultraviolet, or UV

If you need the maximum amount available for marking and engraving materials, then you need a laser UV marker. It has a wavelength of 355 nm, the shortest one, and can process a lot: from ceramics, stone, and plastic to silver, diamonds, and circuit boards!

Additionally, this marker has the smallest laser dot diameter, and with it you can get miniature logos, bar codes or QRs, images, inscriptions, and many more in high resolution.

Lenses

It’s important to talk about lenses as well when we are trying to answer the question “How do laser engravers work?”. This is one of the key elements of the laser marker: it directly affects the heat impact applied to the material.

The lens can change the machine’s application, allow you to mark with it, engrave, or even clean!

• How exactly do lenses affect the process?

It is a focusing element that gives the laser the final diameter that ends up being on the workpiece surface: the smaller the lens, the smaller the dot where the whole laser power is concentrated.

Lenses are of various sizes, and sizes are also referred to as working fields, from 50×50 mm up to 300×300 mm.

• Which lenses are good for laser engraving?

It depends on the material and depth of engraving you want. However, lenses with a working field of 200×200 mm and smaller are recommended since you need to increase the impact laser does to the material.

How do laser engravers work: deep engraving

There is one interesting form of engraving, called deep engraving. To achieve it, you need to set a big amount of passes. For example, after 100 passes, you can get a 5 mm deep engraving on a stone. The number and depth vary depending on the workpiece characteristics.

But be alarmed! The more passes you set, the longer time it will take to mark a single workpiece.

One more thing that is crucial in this question is a focus. In the case of deep engraving, layer after layer will be removed, and with time this will lead to the need for focus adjustment. That means that during the process, you’ll have to check and lower the focus manually to gain precise and smooth engraving. If you ignore that, then a defocus or blur may appear.

However, that can be used as an artistic choice to show the depth effect.
There is a different option. Wattsan FL TT can be equipped with a dynamic 3D autofocus system. Produced for the customer if they need precise and three-dimensional photos even on an uneven surface, this type of model is known as FL 3D.

Applications

• Medicine: marking on the instruments and other devices is required.
• Automotive and aerospace industries;
• Interior and exterior decor;
• Jewelry business;
• Electronics;
• Wire and cable production;
• Food;
• etc.

Choosing marker for your goals

Based on material

It is clear from the above that the choice of the laser marking machine starts from the understanding of application and materials.

• If you know that metal is not going to be processed, then a CO2 laser is good for you;
• If your main workpieces are metallic, then choose FL TT;
• If you plan to work with various types or with precious metals, then a UV TT marker is better.

Sphere of work: power and lens

These two are determined by the goals of your production. For example, for silver and tungsten laser engraving, you would need a marker with at least 30 W of power and a working field of 100×100 mm, or 200×200 sometimes. However, for processing stones and ceramics, it’s better to use a 50W laser source.

Conclusion

1. How does laser engraving work? It is achieved by evaporating or burning material, which means selective layer removal via the transition from solid to gaseous state without heating the liquid or melting phase. 
2. All materials have their wavelength absorptivity. That’s why Wattsan has three types of laser sources and markers so you would find the right one for you—CO2, fiber, or ultraviolet. 
3. Lenses are one of the key elements of the laser marker: they directly affect the heat impact applied to the material. Lenses with a working field of 200×200 mm and smaller are recommended for laser engraving.