Laser cutting is quite an interesting technology that is often utilised for industrial manufacturing purposes, but its popularity is gaining momentum with small businesses and even hobbyists. It has a long history dating back to 1965 when the world’s first ever laser cutting machine was developed for the purposes of drilling holes in diamond dies.
How does a laser cutter work?
In a nutshell, the process of laser cutting works by concentrating the focus of a high-powered laser on a given area. Laser cutters are computer controlled, which means that they are able to create cuts into objects with a high level of precision.
The laser burns, blows away or vapourises away the area it is directed at, resulting in a really clean finish.
Types of laser cutter
There are basically two different types of laser cutter in use today:
CO2 lasers pass a current through a pumped gas mixture of carbon, nitrogen, hydrogen and helium (DC-excited) or use radio-frequency (RF-excited) energy. RF methods are newer and more popular than DC methods, because DC methods of laser cutting are prone to electrode erosion and plating of electrode material on glass and optics. CO2 lasers are often employed to cut, bore and engrave materials such as metal, plastic, wood, paper, wax and fabric on an industrial scale.
Neodymium (Nd) lasers work in a similar way to CO2 lasers but use optics instead of gas. These neodymium lasers are primarily used for cutting and engraving on to metals and ceramics.
How are objects cut with precision?
Well if a laser is simply pointed at an object then it will not cut or engrave with any degree of accuracy unless the laser beam is modified.
To give you an analogy, if you were outside on a hot summer’s day and wanted to light up some wood up to make a bonfire, the sun (although bright and hot) will not easily set fire to the wood. But if you had a magnifying glass and you concentrated the magnifying glass on the wood, you will very shortly see the wood start to smoke and then become alight.
This is essentially how a laser cutter works, by using optics to concentrate the laser direction on to a specific area. Because the energy used in a laser beam is so intense, it can easily cut through solid objects like steel. As you may have gathered, great care has to be taken when using a laser cutter as it can potentially be a dangerous tool.
In order to achieve the desired end result and finish, certain cutting processes need to be used with particular types of objects.
Usually, a concentrated jet of gas (melt and blow or fusion cutting) or water is sprayed behind the laser so that any debris from cuts are literally blown away, resulting in a perfect finish. This method is used with metal.
For materials that do not melt (such as wood), an appropriate method of cutting would be to use vapourisation.
Brittle materials such as glass can be cut using the heat from a laser beam to form cracks on it.