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Waterjet Cutting vs. Laser Cutting
Have you ever wondered how high-tech, precise metal laser cutting is achieved? The answer lies in two cutting-edge methods-waterjet and laser cutting. Each method has its particular strengths and weaknesses. Let’s delve into these technologies and explore some additional tips for cutting metal.
Definition of Waterjet Cutting
Waterjet cutting utilizes a high-pressure stream of water combined with an abrasive substance to cut through a wide range of materials. The water flows through high-pressure tubing into the cutting head, passing through a nozzle, creating an excellent stream to cut the material. Waterjet cutting machines can produce pressures as high as 100,000 psi. There are two kinds of waterjet cutting processes: pure waterjet cutting and abrasive waterjet cutting.
How Does Waterjet Cutting Work?
Wood, rubber, and plastic can be cut using waterjet machining. To cut harder materials like metals and stones, an abrasive material is mixed with water. Water from the reservoir is pressurized using an intensifier to about 4000 bars. This high-pressure water is then directed through a nozzle and converted into kinetic energy. Abrasives like aluminum oxide or garnet are added to the water in the nozzle’s mixing chamber. When this fast-moving water hits a workpiece’s surface, it removes materials.
Advantages and Disadvantages of Waterjet Cutting vs. Laser Cutting
Advantages
Waterjet cutting is beneficial for cutting through thick materials, as it can handle more material than laser cutting. Waterjet cutting is a cold-cutting method that does not introduce heat to the material being cut. In contrast, laser cutting generates high levels of heat and radiation.
Furthermore, waterjet cutting does not produce any hazardous byproducts, whereas laser cutting, depending on the material, may produce hazardous vapors that require a ventilation system.
Moreover, waterjet cutting results in clean and smooth cuts that usually do not require additional post-processing. Conversely, laser cutting can leave burn marks, necessitating cleaning of the affected area or part.
Disadvantages
Waterjet cutting is less precise than laser cutting and is better for high-precision applications. Laser cutting is faster than water jet cutting for materials less than one inch thick, but the advantage of laser cutting diminishes for materials close to or more than one inch thick. Waterjet cutting is considered environmentally friendly but requires water treatment to remove the used abrasive, and the solid waste may need hazardous disposal. Laser cutting requires proper ventilation and an air filtering system to capture particulates from the metal vaporization process.
Definition of Laser Cutting
Laser cutting uses a high-powered laser to engrave or cut materials by moving them along a flatbed. It is suitable for wood, cardboard, acrylic, and other materials.
How Does Laser Cutting Work?
Laser cutting involves using a high-power laser directed through optics and computer numerical control (CNC) to cut materials. A motion control system follows a CNC or G-code pattern to direct the laser beam onto the material, producing a high-quality surface finish. The laser beam is formed by stimulating lasing materials through electrical discharges or lamps inside a closed container. The beam is then focused at the work area by mirrors or fiber optics and directed through a lens for intensification. The narrowest point of a laser beam is typically under 0.0125 inches (0.32 mm) in diameter, with possible kerf widths as small as 0.004 inches (0.10mm) depending on material thickness. When the cutting process needs to start away from the edge of the material, a piercing process is used, which involves a high-power pulsed laser making a hole in the material. For example, it may take 5-15 seconds to burn through a 0.5-inch-thick (13 mm) stainless steel sheet.
Advantages and Disadvantages of Laser Cutting vs. Waterjet Cutting
Advantages
The laser cutting method is quieter than water jet cutting. A laser cutter makes a 75 dB sound, while a waterjet cutter can reach up to 90 dB. A laser cutter is generally faster, cutting at 20-70 inches per minute, compared to a waterjet cutter’s 1-20 inches per minute.
Moreover, laser cutting produces less solid and liquid waste than waterjet cutting. Laser cutting uses light as a cutter, while waterjet cutting produces liquid (used water) and solid waste (cutting abrasive + feedstock particles) that requires proper treatment for recycling or disposal.
For precision in design, laser cutting is the better choice. The minimum cutting slit size for a laser cutter is 0.15 mm, while for a waterjet cutter it is 0.5 mm.
Disadvantages
Lasers can cut materials up to about 30 mm thick, with the most powerful lasers making cuts up to 40 mm. Waterjet cutting is better for thicker materials, able to slice through parts as thick as 250-300 mm. Laser cutting produces hazardous vapors and requires good ventilation. In contrast, waterjet cutting is more environmentally friendly as it generates no fumes.
Laser Cutting vs. Waterjet Cutting: Materials Compare
The choice between waterjet cutting and laser cutting depends on the material to be cut. Laser cutting can be used with different materials such as metal, glass, plastic, and wood. However, it is unsuitable for reflective materials as the energy is reflected off the metal instead of being used to cut. It is also unsuitable for materials sensitive to heat as they may decompose when heat is applied. On the other hand, waterjet cutting can be used with a broad range of materials except tempered glass or diamonds. Waterjet cutting uses pressurized water to cut materials without generating heat.
Laser Cutting vs. Waterjet Cutting: Cost Comparison
Laser cutting is a cost-effective tooling option because there is no need for expensive tooling equipment – you program the cutting path and step aside. The laser, the critical component, is also inexpensive due to high demand. Aside from the initial purchase, the main cost of running a laser cutter is the power needed to operate the machine. If you’re outsourcing your cutting, this cost will be factored into the vendor’s operating expenses.
Waterjet cutting is typically more expensive because of component wear and the need to replace consumables. In addition to a water pump that requires periodic maintenance, you’ll need nozzles, seals, cutting water, cooling water, and an abrasive medium to use with the water in the machine. The water jet cutter doesn’t require tooling; someone can program the cutting path in the CNC.
Speed Compare of Laser Cutting vs. Waterjet Cutting
Speed is a critical factor that distinguishes laser cutters from waterjet cutters.
Laser cutters can typically cut more efficiently, with some models capable of cutting up to 70 inches of material per minute.
On the other hand, waterjet cutters usually can’t exceed cutting speeds of 20 inches per minute.”
Laser Cutting vs. Waterjet Cutting: Versatility
Laser cutters can’t cut marble but can handle metals, plastics, and fabrics, with limitations on metal thickness based on machine wattage. Waterjet cutters are highly versatile and can cut through almost any material, with cutting depth determined by water pressure and abrasives used in the jet.
Laser Cutting vs. Waterjet Cutting: Accuracy
Laser cutters can cut with extreme precision, achieving accuracy as close as +/– 0.005 inches. On the other hand, waterjet cutters offer a precision within +/– 0.02 inches.
Viable Alternatives to Laser Cutting and Waterjet Cutting
Some alternative methods to laser cutting and waterjet cutting are:
Plasma Cutting: This method uses ionized gas at very high temperatures to melt through materials. It requires the materials to be electrically conductive. A plasma-cutting machine can cut materials like aluminum, nickel, titanium, stainless steel, and plain carbon steel.
Oxy-Fuel Cutting: In this method, metal is heated to its ignition temperature using a mix of oxygen and fuel gas, such as acetylene. Then, a jet of pure oxygen is directed into the heated area, causing a chemical reaction that creates iron oxide or slag. The oxygen jet removes the slag, allowing the metal to be cut. This method doesn’t work on non-ferrous metals because they form metal oxides with higher melting temperatures, creating a protective scale instead of being cut away.
