At the heart of every 10.6µm laser cutting machine is the laser source. For low power (<100w) laser cutters there are two different types of laser source most commonly available.Both are essentially gas lasers emitting a laser at the 10.6µm wavelength but here the similarity ends. We cover the specification and manufacture differences between these technologies in other articles.
The oldest, most stable and reliable, highest performing laser is the RF variety. A high quality RF excited laser can produce excellent beam quality with a very short (fast) rise/fall time. This makes the RF laser ideal for laser cutters where the process needs to be delivered at high speed.
RF lasers are also much better for applications that require a high degree of detail to be cut. This is because when the motion system slows down to turn an acute angle or change in direction, to avoid burning-out the material where the motion system turns/dwells the laser power must be ramped down proportionally. DC lasers are difficult to control when ramping, often producing unreliable results.
The high-speed pulse of the RF laser is also much better suited for laser cutting materials that react adversely to overheating where the RF laser will minimise this undesirable reaction. For example, laser cutting wood with an RF laser can produce a cleaner edge than when using a DC laser. Another example would be the laser cutting of thin materials, such as laser cutting veneers where too much heat can cause the material to warp. Using an RF laser will again minimise this adverse effect.
Another preferred application for using an RF laser is where the cutting control needs to be very precise: for example, the laser kiss-cutting of labels where the laser cuts the surface material but not the backing paper. This application can require the use of very low laser power, even just a few watts. All gas lasers do not work well when the duty cycle falls near to or below 10%. For DC lasers at 60w we find they do not perform well below 30% (18w), which is often too much power for kiss-cutting.
A DC laser is best applied to laser cutting materials that work well with heat and where the duty cycle is almost always 100%. For example, laser cutting acrylic, especially at thickness >3mm (1/8”) where the slower pulse and greater heat of the DC laser can be an advantage. In this example a DC laser will often laser cut acrylic with a far smoother edge than its RF alternative.
Of course, DC lasers being a fraction of the price of the RF alternative means the user can afford to use a far higher DC laser power than the nearest cost RF alternative closest in price. This means that using a higher power DC you can cut thicker materials much faster. For example, one of our 30w RF machines actually costs more money than the same machine fitted with a 100w DC laser. In this example, the DC version would cut thicker materials near to three times faster.
At Lotus Laser Systems we manufacture a wide range laser marking and engraving solutions ideally configured for laser cutting, laser marking and laser engraving all types of materials. Our experts would be happy to recommend which configuration best suits your application.
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