subject: Laser Cutting For Producing Precise Metal Shapes [print this page] Laser cutting is an industrial process used to cut precise metal shapes from sheet, plate or tube stock. It is often the initial step in sheet metal fabrication. The parts cut by lasers most often move to secondary metal fabrication operations such as forming, machining and welding and will eventually end up as machinery, toys, vehicles or a large host other items. Laser cutting can actually be used to cut a wide variety of materials: metals including stainless steel, mild steel, aluminum, copper, as well as non-metals such as wood, plastics, silicon wafers, paper, glass and more.
Inside the laser cutting machine, a laser beam is generated by stimulating lasing material, often CO2, by electrical discharges in a closed container, called a resonator. The beam is then internally reflected to obtain and focus the energy into a monochromatic beam of coherent light. This light is focused at the work zone and the material is melted and blown from the material. Nitrogen is the gas most often used to blow the melted material out of the cut, but oxygen or other gases can also be used. Adjustments to the amount of power, the feed rate, and type and flow rate of gas, must be made by skilled laser operators to be able to achieve optimal cutting quality and rates.
There are several ways the laser beam is delivered to the material to be cut. Either the laser beam itself needs to move, the material being cut needs to move, or, both the laser and the material moves so that the desired shape can be cut. When the laser head itself moves, it is often referred to the flying optics system. This method is the fastest at cutting, however, requires a more complicated optic system to take into account the changing beam length from the resonator to the work piece. To the contrary, a stationary head laser requires a simpler beam delivery system, but operates slower than the flying optics system. The hybrid laser system is a combination of the previous two methods and employs the optic head to move along the shorter X axis while the bed provides movement along the longer, Y, axis resulting in a more constant beam delivery path and using a simpler beam delivery system than the full flying optics method. This system has more capacity per watt than flying optics machines and operates at a speed between the other two systems.
Regardless of the optic system used by a laser cutting machine, it must get the information it needs to cuts the parts to the specifications on the print. All modern lasers operate with a computer numerically controlled (CNC) system. There are a variety of programming software systems that can be used, some so automated that it can take a print made in certain programs such as solid works, and generate the code needed to make the part with little human input. Radan is one software that has this capability. Software will nest parts for best sheet use and also reduces or eliminates programming time and error.
In summary, laser cutting is an excellent and precise method of cutting metal shapes that may or may not need further metal fabrication processes. There are numerous methods of laser cutting of which several are described above. These variables go into determining the cost of cutting parts. A laser cutter should be able to provide quality parts at a good price and a quick turn-around time.
