Introduction
When laser cutting sheet metal, lines can often be seen running down the cut edges. These are called striations and are a normal characteristic of laser cutting. Several factors affect their appearance. Read on to find out what to expect from a laser cut part.
What Are Striations on a Laser-Cut Edge and Why Do They Form?
When a laser cuts through sheet metal, the laser melts the material along the cutting line. An assist gas, either nitrogen or oxygen, blows the molten metal out of the cut. This process creates lines along the edge, which are called striations.
Their appearance depends on several factors, including the material thickness, cutting speed and cutting settings.
Striations are a normal characteristic of laser cutting and are often visible on cut edges. They are more noticeable when cutting thicker plate. At Midtherm Laser, we can cut mild steel, stainless steel and aluminium up to 30mm thick, where the striations can be clearly seen.
This isn’t anything to be concerned about. The part can still be within tolerance and have a good-quality finish, as long as the striations are consistent.
However there are many aspects that can have an effect on the cut edge. This is when quality issues can arise.
Laser Cutting at Midtherm Laser
At Midtherm Laser, we always aim to produce the best-quality cut we can. However, the finished edge can be affected by several factors, including the machine settings, the operator, the material and the assist gas used.
Material quality is particularly important. We always aim to source good-quality material, as surface imperfections and impurities can affect how the metal reacts during cutting. This can lead to inconsistent edges and may mean additional finishing is needed.
Our operators check the cut edges for consistency. If a part doesn’t look right, it can be pulled aside for further inspection, and we may recut parts where necessary.
As you can see in the photographs of the 30mm mild steel plate, the striations are clearly visible along the cut edge. There is also a noticeable change in their appearance partway down the thickness of the plate. The laser’s focus position is one of several factors that affect the cut. Finding the right balance between the focus, material, cutting settings and assist gas is important to achieve a consistent edge.
Conclusion
Striations are a normal characteristic of laser cutting, but their appearance can vary depending on the material and cutting conditions. Visible striations don’t automatically mean there’s a problem, but consistency and overall edge quality are important.
If you’d like to know more, have any questions or are experiencing issues with a laser-cut part, speak to our team. We can offer support and advice for your next laser cut project.
