Technologies

What is Plasma? The Fourth State of Matter

One common description of plasma is to describe it as the fourth state of matter. We normally think of the three states of matter as solid, liquid and gas. For a common element, water, these three states are ice, water and steam. The difference between these states relates to their energy levels. When we add energy in the form of heat to ice, the ice melts and forms water. When we add more energy, the water vaporizes into hydrogen and oxygen, in the form of steam. By adding more energy to steam these gases become ionized. This ionization process causes the gas to become electrically conductive. This electrically conductive, ionized gas is called a plasma

How Plasma Cuts Through Metal

The plasma cutting process, as used in the cutting of electrically conductive metals, utilizes this electrically conductive gas to transfer energy from an electrical power source through a plasma cutting torch to the material being cut. The basic plasma arc cutting system consists of a power supply, an arc starting circuit and a torch. These system components provide the electrical energy, ionization capability and process control that is necessary to produce high quality, highly productive cuts on a variety of different materials. The power supply is a constant current DC power source. The open circuit voltage is typically in the range of 240 to 400 VDC. The output current (amperage) of the power supply determines the speed and cut thickness capability of the system. The main function of the power supply is to provide the correct energy to maintain the plasma arc after ionization. The arc starting circuit is a high frequency generator circuit that produces an AC voltage of 5,000 to 10,000 volts at approximately 2 megahertz. This voltage is used to create a high intensity arc inside the torch to ionize the gas, thereby producing the plasma. The Torch serves as the holder for the consumable nozzle and electrode, and provides cooling (either gas or water) to these parts. The nozzle and electrode constrict and maintain the plasma jet.

The Oxy-cutting is a process of cutting metals by oxidation but still localized, using a jet of pure oxygen. It is necessary for this, to bring the starting point (where we will start cutting) at a temperature of 1300 °C, It is called pre-heat. A flame heating (oxy-gas) for the pre-heat and maintain the cut, where several types of gases such as acetylene, may be used. A central cutting jet of pure oxygen, coming in the middle of nozzle, which enables the combustion in the slot and through the thickness to be cut. The jet cutting also has a mechanical role of removal of oxides formed (slag). The cutting efficiency is improved by a very high purity oxygen.

Waterjet cutting is one of the most versatile cutting processes around. Well suited for high-performance metal cutting, waterjet technology, when used with an abrasive additive, creates a clean, burr-free cut that does not require secondary finishing and does not leave a heat-affected zone. Nearly every type of cut is possible, from rapid hole drilling to detailed cuts for automotive applications. Waterjet cutting systems are also less expensive than laser-cutting systems, making them a solid choice for metal and steel cutting in the fabrication industry. The addition of abrasive widens the range of cuts that waterjet technology can perform, but abrasive is often one of the most expensive components of a waterjet cutting system. To offset the costs of using abrasives in water jets to cut harder materials, KMT Waterjet had developed a system that regulates the amount of abrasive used, controls the flow, and eliminates waste. Better abrasive management makes cutting with water a truly efficient process. To learn more about water jet cutting for metal applications, please see the information included below.

Fiber lasers use single emitter semiconductor diodes as the light source to pump the cladding of special optical fibers doped with rare earth ions. The laser beam emitted is contained within optical fibers and delivered through an armoured flexible cable. Fiber lasers deliver their energy through an integrated flexible optical fiber that can be up to 200 meters long. Fiber lasers are smaller and lighter in weight that traditional lasers, saving valuable floor space. Fiber lasers are upgradeable, additional optical modules can be added to increase power as operations increase.