How Metal Composition and Quality Affect Edge Quality in Laser Cutting
Lasers have dramatically changed the way metal fabrication is done. High-speed laser cutting services have enabled faster production times, efficient use of materials and a repeatable, controlled process that produces a standard quality cut.
As a metal fabricator, in order to produce a high-quality edge, it is important to take into consideration the composition and quality of the metal being cut. Here's why:
Material Composition
The composition of a metal affects its conductivity and viscosity in a liquid state. These factors greatly affect the laser processing of the metal, perhaps more than they affect any other kind of processing.
The viscosity of the metal in liquid state will determine whether the dross produced during laser processing will stick to the edge of the metal part or not. If the viscosity is thin, then the dross can simply be blown away during the cutting process, producing a high-quality edge. However, if the viscosity is thick, the dross will stick to the edge of the metal part, causing an elevation in the temperature of the part (higher conductivity). To counter this, another process will have to be done to remove the recast.
The metal composition also affects how the metal part reacts during a laser process. For instance, higher-carbon steels are regarded as higher quality and therefore used for structural purposes. However, when compared with homogenous steels, carbon steels contain a wide range of elements with different melting points. This means that random reactions can occur during laser cutting, lowering the quality of the cut edges.
Material Quality
Laser cutting is highly affected by the quality of the metal. For instance, it is important to have a high quality surface finish for the metal part before taking it through the laser cutting process.
This is because any impurities found on the surface of the metal part will be highly reactive to the laser's heat and cause a recast layer to be formed along the edges of the cut metal part. This recast layer tends to be highly stressed and could crack, especially if the material is an oxide. These cracks could move into the metal part, creating larger cracks and eventually damaging the metal part.
Certain kinds of steel can present challenges when it comes to the material quality suitable for laser cutting. For instance, when cutting hot rolled steel, the surface tends to melt in with the metal, producing a poor quality finish on the cut.
