Before start to cut, there are some things that the installer and operators need to know about the relation of materials with the temperature which means that we have three basic important concepts need to understand.

The first one is the melting or fusion point in the metals. This is the temperature (Melting point) that material needs to get melt. We need to know this to understand why we are using different gases while we are cutting the materials.

The second concept is the thermal conductivity, this is the capacity that a material has to get heat and conduct the temperature through the material. Also, very important for some special cases.

The final concept is the reflection, this is the value that a material has to reflect a light, and we know that the laser is a light so have to know the relation between this concept and the materials.

Here is a chart that shows the values for each material:

Carbon Steel:

As you can see we need more temperature to melt the carbon steel, that´s why we use the oxygen to cut it because this gas provides less cooling than the nitrogen while the laser is going through the material. That means that the utilization of oxygen provides the temperature necessary to cut the carbon steel. Also, the thermal conductivity of this material is low, which means that we have to cut it slow because the heat inside the material is expanding really slow, but it doesn’t mean that it´s not going to get hot and finally, the reflection on this material is very low, so no problem with this.

Aluminum 6061

The melting point for the aluminum is low than the other materials, but it´s hard to cut it because it´s an alloy of too many materials which make it very strong for the cut. Also, the thermal conductivity is really high, which means that the material takes short time to get hot and in relation with the reflection is a dangerous match because when you have more temperature you will have more reflection, that why we use nitrogen to cut the aluminum.

Stainless Steel

For the SS, we need almost the temperature than de CS, but the difference with this material is the thermal conductivity, that little change of percentage in the melting point which means that the thermal conductivity is significant for the operation of this material. We need 1400°C to melt the material but the 17% of thermal conductivity is enough to melt it, that´s why we use nitrogen in this material because it melts faster than the CS, if we use oxygen is going to melt faster and burn the material. Also, the reflection is really high, another reason why we use the nitrogen to cut it when you have high temperatures the reflection is going up.