CO2 Laser Cutting
Carbon Dioxide (CO2) laser cutting has transformed manufacturing in recent years. CO2 laser cutting offers precise machining of a wide range of materials at low cost. Most CO2 laser cutters run under electric power.
Laser cutters consist of a glass tube containing a series of mirrors and lenses which bend and direct the laser beam to its target. The laser beam follows CNC (Computer Numerically Controlled) instructions from a CAD vector file. The first CO2 laser cutter was developed by Kumar Patel at Bell Labs in 1963. Within four years, the first 1kW CO2 lasers appeared on the market.
CO2 laser beams are used to cut or engrave flat sheet materials, such as stainless steel. Cutting is achieved either by very fine-tuned burning, melting or vaporization of the material. Even with plastics, a professional finish can still be obtained by melting and vaporizing the surface.
How a CO2 Cutting Laser Works
CO2 cutting lasers are incredibly versatile. The narrowly focused beam can cut intricate shapes from all types, and thicknesses, of metal alloy plate. A laser beam makes such an efficient cutter because it is made up of high intensity, single-wavelength light. With a CO2 laser beam, its wavelength is in the infrared spectrum, meaning it is invisible to the human eye.
A curved mirror in the laser’s cutting head directs the beam through the nozzle bore. As the head passes over the plate, the laser beam cuts or engraves precisely on the spot. A compressed gas, such as Nitrogen, helps to blow bits of kerf (or debris) out of the cutting area.
The machine will automatically raise or lower the cutting head by minuscule amounts to maintain a uniform focal point. Keeping the laser beam focused as a consistent, high-energy pinpoint, ensures accurate and efficient cutting.
The temperature achieved with such high power density rapidly melts or vaporizes the metal alloy plate. A CO2 cutting laser generates a lot of heat. To combat overheating, cold water is re-circulated through a water chiller connected to the laser tube.
Flexible Fabrication Design with CO2 Laser Cutting
Adjusting the settings on a CO2 cutting laser varies the quality and finish of the cut, i.e., making it coarser or finer. You can reduce the power for thinner or less robust materials, as well as slow the cutting speed to prevent burning at the edges of cuts.
Because the cutting beam focuses to a pinpoint, there is far less kerf than you would get with a standard steel blade. While the kerf is minimal, it is still wise to leave a couple of millimeters spare between the parts while marking them on the sheet.
Most industrial processes involve the laser beam passing all the way through the material, separating it into two pieces. However, the laser can be adjusted to create a partial cut, and is used in two common methods of engraving:
- Vector engraving – the laser beam engraves an outline.
- Raster engraving – the laser ‘prints’ an infill engraving.
CO2 laser cutting can be used to cut or engrave materials as diverse as paper, plywood, and acrylics. In fact, CO2 laser cutting stainless steel is very prominent in the fabrication industry. Metals are worked using industrial-sized CO2 cutting lasers.
CO2 laser cutting allows a quick turnover of bespoke design parts at very low cost. Prototype parts can be produced, tested, and turned over for high-volume manufacturing, in the space of a day. CO2 laser cutting is an indispensable manufacturing process for most fabrication jobs. Contact one of our representatives to learn more about our laser cutting process.
Fiber Laser Cutting
Over the last decade a new, “cutting-edge” technology has emerged to challenge the CO2 laser cutter. Fiber laser techniques are cornering the market for thinner sheets of aluminum and stainless steel. Fiber laser cutting services have a faster turnaround and, with lower overheads, will pass the benefit to the customer, reducing cost.
Through Thick and Thin
So, what is so different about a fiber laser cutter compared to a CO2 laser cutter? The first point to make is that both types of laser cutter have their pros and cons, and which is the better option will usually depend on the material to be cut.
As a rule, the thinner the material, the faster the cutting speed, the lower the labor costs. Cutting rates of two to three times of what you would expect from a CO2 laser have been obtained on materials up to a half inch thick. The reduced cutting times are most obvious for straight line work, but intricate curves are also cut much faster if the material is not too thick.
Fiber laser cutting machines can tackle metals with high reflective surfaces more efficiently than traditional methods. Sometimes laser cutting on reflective metals, such as sheets of copper and brass, risks damaging the machine due to back reflections. With a fiber laser cutter, the beam is focused on an infinitesimally small point, and the high density of this energy virtually nullifies back reflections.
Where you win with CO2 lasers is if you are cutting through a thicker material, usually something that measures more than a quarter of an inch. The CO2 laser offers faster cutting times in a straight line with these thicknesses and pierces the material at the start of the cut faster too. For a smoother finish on thicker cut materials, a CO2 laser might be preferable.
How Fiber Laser Cutting Machines Work
To appreciate how a fiber laser can produce such a tight, focused beam, you have to understand how a fiber laser cutting machine works. A CO2 laser cutter has a series of mirrors and lenses to bend and direct the light. The fiber laser cutting machine boasts a direct design, whereby the light passes through fiber optic cable.
The fiber optic cable is made from silica glass. The active core, where the laser light is generated, is doped with rare-earth elements, such as Erbium, Ytterbium or Neodymium. A diode laser pump injects light into a laser cavity. Here, electrons are excited, reflected and amplified and emerge as a tight, powerful laser beam.
Early fiber lasers could only produce an output of a few mini-watts. Today’s fiber laser cutting machines can generate laser beams of 0.5 to 3kW and more. Better still, the laser is created within a compact nozzle head. The resulting beam is straight and stable. It is also less prone to misdirection from accidental knocks.
Why Fiber Laser Cutting Machines are Here to Stay
Fiber lasers are easy to use and very reliable, with minimal overhead. There are no expensive mirrors and lenses to set up and maintain. In fact, the fiber laser cutting machine is almost maintenance-free.
They are also more optically and electrically efficient. Not only does this mean that most of the power generated goes into cutting the metal, but less gets converted into waste heat. Consequently, less water cooling is required. A fiber laser consists of up to 80% of its power input, a much higher efficiency than either gas or crystal lasers.
Many industry sectors are now switching to fiber laser cutting because of the faster processing times it offers. New fiber laser metal cutting machines are combining ever higher power output with reductions in energy input. This is leading to cheaper commercial runs and prototyping. Speak to one of our team members to learn more about our fiber laser cutting technique.