It’s hard to believe that a beam of light can cut through thick wood or even a bar of steel. Incredibly, this is not the only baffling thing about laser cutters. Here are a few other facts about the technology that might leave you exploring further.
Most people think it’s a brand new technology. Not true. Laser cutting has been around since the 1950s. The first laser machine was constructed in the early 1950s but it took until the1970s for laser cutting to become a reality for manufacturing. Then a few more decades passed before it achieved the popularity it enjoys today.
Engraving industry publication Engraver’s Journal said it was only after the inception of the micro-computer that laser cutting gained popularity.
The past decade featured numerous technology advancements. Today, there are over 25,000 high-power laser cutting applications. Now lasers can cut a wide variety of materials from paper, wood, fabrics, acrylic and various other plastics. The mainstay of manufacturing is the CO² laser which excels at cutting low alloy and non-allowed steels, stainless steel, titanium and its allows, nickel alloys and aluminium and its allows.
Many different types of lasers have been developed (dye, solid state and semiconductor just to name a few) and they each have their own niche in human endeavour. This shows the technology’s increased importance.
You also need a higher laser intensity to cut through thicker material. If the laser intensity is low, you may be able to cut through thin sheets but not metal bars. Lasers are usually measured in terms of power i.e. 1,000 watts, or 1kWatt. The power is calculated as the total energy emitted in the form of laser light per second.
Laser intensity is determined by dividing the power by the area over which the laser is distributed. For instance, a 1kWatt laser beam distributed over a diameter of 0.1 mm will result in an intensity of approximately 125,000 watts per mm².
A lens with a short focal length produces a small spot size and short depth of focus. This in turn helps in shortening the cutting time and in achieving superior cutting quality, especially in cutting thin metal sheets.
However; for thicker material a short focal length would give a beam that is too wide to keep the material molten as it exits the sheet at the bottom of the cut and there would be too much taper on the edge.
So for thicker material a longer focal length is used to achieve optimum depth of focus and maintain laser intensity and cutting speed.
Generally, oxygen cutting is cheaper than nitrogen cutting. Mild Steels are cut with Oxygen at relatively low pressures because of the exothermic effect of iron in an environment enriched by Oxygen. That is the Oxygen assists the cutting. In comparison most other metals are cut with Nitrogen as the assist gas because the laser beam has to do all the work of melting the material in its path, the assist gas is used at high pressure to blow the molten metal out of the cut path.
For some applications, cutting plastics, wood or paper compressed air is sufficient to keep the progressive cut clean. The assist gas pressure may be as low as 30 kPa (4.3 psi) for thin acrylic and up to 2000 kPa (290 psi) for 16mm Stainless Steel. Both the beam and the assist gas exit through a nozzle just above the surface of the material being cut.
The assist gas also helps to keep the lens cool and reduces the amount of molten material that can travel back up through the nozzle and splatter on the lens.
Laser cutting is a safe and environmentally sustainable method of cutting. Operator safety is of paramount importance and many fail safe checks are built into the process.
Laser cutting is quiet, permits the most efficient use of materials, and restricts harmful fumes to a specified interaction chamber – remote from the user – that can be easily ventilated.
There are many other interesting facts about laser cutting. For instance, some of today’s lasers are so small they can be hooked to a desktop, just like a printer! Sounds unreal, right? And another one – laser cutting can be used to create an endless variety of items including metal tags, signs, clock faces, leather upholstery, and many others.
If you’re already attracted to lasers, these fun facts can help you fall in love with the cutting technology even more!