A Comprehensive Guide to the Types of Laser Cutting Methods

A Comprehensive Guide to the 4 Types of Laser Cutting Methods

Laser cutting is a type of machining that operates without physical contact and provides precise control over energy density. Concentrating the laser beam creates a light spot with high energy density, which offers several benefits during cutting operations. Laser cutting relies on four distinct techniques to address various cutting scenarios effectively. Let’s discuss each of the four types of laser cutting methods in this article.

Fusion Cutting

Laser fusion cutting partly melts the workpiece and uses airflow to remove the molten material. The procedure is known as laser fusion cutting because the transferring of material happens solely in its liquid form. A high-purity inert cutting gas accompanies the laser beam, which helps the melted material to leave the slot, and the gas itself does not take part in the cutting process.

Since the energy needed for gasification is often more than the energy necessary to melt the material, laser fusion cutting provides a faster cutting speed than gasification. The laser beam is simply absorbed in laser fusion cutting, and the maximum cutting speed increases with laser power. However, it decreases with the increase in plate thickness and material melting temperature.

When the laser power is below a particular threshold, the air pressure at the slot as well as the material’s thermal conductivity are the limiting factors. Because there is melting, laser fusion cutting can successfully make a non-oxidizing incision for iron, steel, and titanium, but it cannot achieve the laser power density necessary for gasification, which is normally around 104W/cm2 to 105W/cm2 for steel materials. 

It is important to note that laser fusion cutting is not suitable for materials such as wood and certain ceramics that do not have a molten state and usually require a thicker incision.

Vaporization Cutting

The process of laser gasification cutting is only suitable for applications where the removal of molten material must be avoided. This technique is typically used in small areas for ferrous alloys, but it cannot be employed for materials like wood or certain ceramics that do not have a molten state, as they are less likely to cause the material to be condensed. Moreover, these materials usually necessitate a thicker incision.

The optimal beam focusing in laser gasification cutting is determined by the thickness of the material and the quality of the beam. The influence of laser power and gasification heat on the ideal focus location is minimal. When the plate thickness is less than a particular value, the maximum cutting speed is inversely linked to the gasification temperature of the material. The required laser power density is larger than 108W/cm2 and varies according to material, beam focus position, and cutting depth.

The velocity of the gas jet limits the maximum cutting speed in laser gasification cutting under certain plate thicknesses.

Fracture-Controlled Cutting

One of the accurate and fast laser cutting technologies for brittle materials prone to heat damage is fracture-controlled cutting via laser beam heating. 

This process involves using a laser beam to heat a targeted area of the brittle material, creating a significant thermal gradient and inducing substantial mechanical deformation within the region. This leads to the formation of a crack in the material. By maintaining a balanced heating gradient, the laser beam can direct the cracks in any desired direction, providing precise control over the cutting process.

Oxidation Melting Cutting (Laser Flame Cutting)

In melting cutting, the use of inert gas is typical, but when a reactive gas like oxygen is employed, the laser beam heats the material and causes it to react chemically with oxygen, generating additional heat that further increases the material’s temperature. This technique is known as oxidation melting cutting.

While the cutting speed for structural steel of the same thickness is higher than fusion cutting, the incisions produced are often suboptimal. The cut seams can be more expansive, the roughness can be more pronounced, the thermal impact zones can be larger, and the edge quality can be poorer.

Laser flame cutting is not ideal for precision modeling or sharp corners, as there is a risk of burning the edges. To mitigate the effects of heat, a pulse mode laser can be employed, and the laser power determines the cutting speed.

When laser power is fixed, the supply of oxygen and the material’s thermal conductivity become the limiting factors.

Wrapping Up

The four laser cutting methods mentioned above are the most widely used in the industry. Depending on the power of the cutting equipment, the processing needs, and the material properties, users can select which of the laser cutting methods is the most suitable for their needs.

Interested to learn more about laser cutting and how it works? Get in touch with us. Our team of experts will take charge of your laser-cutting project. 

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