How to Deal with Reflective Metals during Laser Cutting?

How to Deal with Reflective Metals during Laser Cutting?

It is extremely difficult to cut highly reflective and non ferrous material by using CO2 laser technology. And as several issues come up when reflective materials are cut using laser machines, a lot of companies do not prefer to use them for cutting reflective metals. Through this article, we will provide you with details about reflective metals and what is the right way to conduct laser cutting on materials having reflective surfaces.

When is a metal known as “highly reflective”?

In order to find out what is highly reflective, it is important to know what the metal consists. Metals like Aluminum and Silver (reflects 95% visible light) are highly reflective and are used in the making of sun glasses, windows, solar

mirrors and jewelry. Reflective metals like gold, bronze, copper and brass are also hard to laser cut using CO2 lasers.

Stainless Steel is also considered to be a reflective metal especially when an object made of steel is given a mirror polish. As the mirror finish makes it difficult to cut steel, it is coated with plastic on the cutting side to lessen the risk.

Why is it difficult to laser cut reflective materials?

As CO2 laser cutting technology makes use of light beams and mirrors for cutting, it becomes difficult to cut reflective metals. If you cut a material like aluminum using a laser machine, the laser beam gets reflected from the metal sheet back to the laser lens causing damage to the laser spare parts. If one is using branded machines like Precitec laser cutting machine, it can incur a damage of thousands of dollars as the laser delivery system might have to undergo a prolonged repairing process and maintenance including replacement of precitec laser spare parts.

Even if you cover the sheet with a non­reflective coating, it doesn’t always work as the surface of the metal is not the only source that reflects light. During laser cutting, heat is generated and a molten metal is released from the laser which reflects and causes damage to the beam. This is the reason why several laser companies suggest an alternate method like Waterjet cutting to cut reflective metals.

However, Waterjet method shouldn’t be considered as an only option for cutting reflective metals.

So how do you cut reflective metals?

Despite the risk of reflected beam damaging the laser machines, it is possible to laser cut these materials. But for that you need to take certain measures and follow some parameters. Usually, the modern laser machines come with a failsafe so that there is no damage to the equipment.

Detectors of the laser head can identify the radiation levels and shut themselves off if a lot of radiation is reflected into the lens. So if the laser and the reflective sheet are set up properly and the job is done slowly and smoothly, it is possible to cut reflective metals.

Fiber laser technology Fiber lasers are the most modern, swift and cost effective way to cut thin reflective metal sheets. As these lasers do not use mirrors and delicate lenses, the reflection from metals like copper, aluminum and brass do not damage the cutting equipment making it quick and safe to set up. So Fiber laser technology is the best way to cut reflective metals.

What Makes Waterjet Cutting a better option?

The only drawback of Fiber Laser Technology is that it can be used effectively only on the sheets that are upto 5mm thick. If the thickness of sheet is more than that, it affects the cutting speed and shape of the cut. This is when Waterjet cutting can come of help. Waterjet cutting cut materials with thicknesses of up to 230mm which makes it even better than the widely accepted CO2 laser cutting technology.

Now that you know how to deal with reflective metals, you can take up this task with ease. All the best!

Steve M Glassner is the General manager of Alternative Parts Inc, the leading manufacturer and distributor of various CNC machine parts including Precitec laser spare parts. Steve is a Machine Tools industry enthusiast and frequently writes about various aspects of the industry.