Posted By: Andy Kamashian | Posted On: October 4, 2018
An Introduction to Lasers
Laser cutting is a relatively new form of sheet metal shape cutting. Without a traditional “tool,” the cuts can be very small and precise. This process also allows for part engraving or etching using lower-power laser settings. Developed in the 1970s for industrial applications, LASER, or Light Amplification Stimulated by Emitted Radiation, became a standard for precision fabrication shops by the end of the 1990s.
How Laser Cutting Machines Work
Using the laser as a heat source and with a shielding gas (typically nitrogen), a laser machine literally burns or melts its way through materials as thick as 1-1/4” steel. Laser cutting can be used for simply shape-cutting flat sheets of materials or in a three-dimensional configuration that can be used for the cutting of preformed pieces.
Because the laser is a heat source, this process may not be considered optimal for heat-sensitive applications or products that may cause hazardous fumes when cut by the laser. Also, because the laser is a light source, highly reflective materials such as copper and brass are generally undesirable to be machined by this method (CO2s especially). Aluminum is also limited in cutting capacity due to its reflectivity and to its excellent properties for absorbing the very heat tjat we are using to cut it. Thus, a laser's cutting capacity for aluminum is typically limited to approximately one-third that of the machine's capability for cutting mild steel, and approximately half of the machine's overall steel cutting capabilities for stainless steels.
Laser machines are available today in different-sized tables from 4' x 4' up to railed gantry machines of 20' wide by 60' long (or larger). The most common table sizes found in today's shops are 4' x 8', 5' x 10' or 6' x 12' and are available as standalone systems, or they can be part of completely automated production cells. Lasers are also available in a series of different wattages of power (also known as Kilowatts or KWs). Cutting capacity and speeds are typically increased by the use of higher wattages. However, the use of higher wattages also increases both the investment cost of the machine as well as its hourly operational cost. Today, machines are available in power ranges from 1,500 Watts (1.5Kw) up to 12,000 Watts (12.0 Kw).
Laser machines are available in two basic machine design types called hybrid or flying optics:
- Hybrid — The term "hybrid" is used when a laser machine moves the material or table in one direction and the laser focusing lens in the other. This design type utilizes fewer moving parts for the beam path delivery system — thus typically requiring less maintenance while providing more (and more consistent) cutting power at the laser cutting head as there are fewer mirrors and focal lenses required.
- Flying Optics — The term "flying optics" is used to describe machines that do not move the material on the bed of the laser. Rather, the laser itself literally “flies” over the material. This design offers the highest rapid rates, acceleration, and possible cutting speeds while being of a slightly more complex design.
Types of Lasers
There are two main types of lasers used in the metal cutting machines we see on the market today:
CO2 laser power sources, called resonators, generate the energy through bouncing a light source off of individual mirrors and exciting the light particles, or ions, with a radio frequency wave or some other method to cause the ions to collide and split — thus amplifying them. The resonator is sealed and pressurized with gasses that are pushed at extreme high velocities with a turbo throughout the laser resonator itself. The laser is then allowed to exit the resonator through a small orifice and then through a carefully orchestrated clean gas-purged delivery system focusing and reflecting the beam on the fly multiple times down to the cutting head. Some newer systems have replaced the beam path delivery system with a fiber optic delivery system.
Direct diode lasers utilize laser diodes to directly output amplified light to an optical fiber cable delivering that light to the cutting head. This system has no moving parts, and requires very little maintenance, making it a preferred option for many new systems.
The term "fiber optics" only refers to the method of beam delivery and not the way the beam is generated. Fiber optic beam delivery is a simpler, cheaper method that eliminates the precise mirrors, lenses, and gasses of the older CO2 type lasers. Fiber optics are the latest technology in metal cutting laser systems.
- Materials Processed: Steel, Aluminum, Stainless Steels, Sheet Plastics, and Wood
- Popular Laser Manufacturers: Amada, Cincinnati, Mazak, Mitsubishi, Trumpf, Bystronic, HK Laser, and Polaris
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