IX Международная студенческая научная конференция Студенческий научный форум - 2017

What is plasma cutting?

This is a cutting system utilizing heat generated by arc discharge between the cutting object material and the electrode inside the torch. Arc discharge heat forms working gas into the plasma state of high temperature; the plasma jet of high temperature and high-speed is blown out from the nozzle

Plasma cutting is the fastest cutting process on carbon steel, aluminum, or stainless steel.

Plasma cutting has come a long way since it was first developed in the late 1950s by engineers at Union Carbide Corp. Today it is one of the most widely used metal plate cutting processes for a large variety of industries.

In the last seven years, developments in plasma cutting technology have come at a fast pace. The latest revision on high-definition machines is their full integration with the CNC machines they are coupled with. New CNCs have touchscreen accessibility, minimizing the number of buttons.

What is Plasma?

All matter is made from atoms, which are essentially the building blocks of everyday objects. Atoms are composed of protons (positively charged), electrons (negatively charged) and neutrons (not charged). Atoms combine to form molecules.

A typical gas atom contains an equal number of both positive and negative charges. Therefore, the positive charges in the nucleus are surrounded by an equal number of negatively charged electrons, and so each atom is electrically neutral. Plasma is formed when the addition of heat (or other energy) causes a number of atoms to release some or all of their electrons. The remaining parts of those atoms are left with a positive charge, and the detached negative electrons are free to move about. Those atoms and the resulting electrically charged gas are said to be "ionized." When enough atoms are ionized to significantly affect the electrical characteristics of the gas, it becomes plasma. Plasma responds to and generates electro-magnetic forces.

A plasma torch uses an alloy copper nozzle to constrict the ionized gas stream to focus the energy to a small cross section. The principle is the same as using a magnifying glass to concentrate the sun's energy to create intense heat.

Certain types of plasma occur in nature, such as the sun and other stars, static electricity, and lightning. There are other types of plasma, man-made ones, which are common in our daily lives, such as neon lights, fluorescent bulbs.

For arc cutting, plasma can also be defined as an electrically heated gas stream. The gas stream is heated to such high temperature that it becomes ionized. The ionized gas by definition can then freely exchange electrons between atoms. This electron movement is what allows the gas to carry the cutting amperage.

CNC Plasma Cutters

CNC Plasma Cutters are also used in many workshops to create decorative metalwork. For instance, commercial and residential signage, wall art, address signs, and outdoor garden art.

In recent years there has been even more development. Traditionally the machines' cutting tables were horizontal, but now vertical CNC plasma cutting machines are available, providing for a smaller footprint, increased flexibility, optimum safety and faster operation.

CNC technology allows systems to communicate to maintain unprecedented levels of control over the quality of plasma cuts.

This level of control is achieved by linking all parameters of a plasma unit to the same CNC unit that instructs the motion of the head, which allows the controller to compute all factors that might affect the quality of a cut. Anytime the material type, thickness, or plasma process is changed, several parameters must be adjusted, such as feed rate, pierce delay, pierce height, and gas mixture. Instead of adjusting dials and making precise measurements before running a job, the operator simply loads the material to be cut and then selects the material type from a menu-driven list on the machine keypad. The controller then automatically configures the machine and the plasma unit. This greatly reduces setup time and nearly eliminates the margin for human error, naturally improving job efficiency, production time, and job quality

For example :

1) Monograph Extreme CNC Plasma Cutter

The Monograph Extreme (pic.1) is a cnc plasma cutter designed to deliver many years of reliable performance and efficient production. It features a unitized downdraft table design, keeping the overall footprint as compact as possible, thus maximizing your production space. This design allows the operator full view of the cutting operation.

pic.1 Monograph Extreme CNC Plasma Cutter (KOIKE)

2) The Crossbow is a CNC cutting system

The Crossbow (pic.2) is a CNC cutting system that is compact, portable and economical. Automated functions and a fully-integrated, user-friendly control provide versatile oxy-fuel or plasma processing. A precision guide rail ensures stable motion of the crossbeam and full support of the cutting torch for accurate, reliable performance. A simple, menu-driven interface is easy to learn and operate. The CNC provides: built-in library of common shapes, USB port for program loading, quick set up pattern nesting, Kerf compensation, drive-enabled switch, crossbow can be equipped with plasma, oxy-fuel or both.

pic.2 The Crossbow is a CNC cutting system (ESAB)

3) NUMOREX (pic.3) designed for heavy-duty operation even under the toughest conditions. The drive system also delivers high acceleration for optimum performance, even on the smallest contours. The NUMOREX™ machine can be equipped with any combination of oxy-fuel, plasma or marking tools. Its crucial advantage lies in its high degree of automation.

pic.3 NUMOREX (ESAB)

Today manufacturers are developing automated systems using microprocessors and state-of-the-art control for current, gas delivery, and torch motion. Plasma cutting has become a cost-effective process, with relatively low expenditures for capital and operation.

Sources

1. www.manufacturingnetwork.com

2. http://www.thefabricator.com

3. https://en.wikipedia.org

4. www.instructables.com

5. http://www.koike.com

6. http://www.esabna.com

Научный руководитель : д.ф.н, профессор Федуленкова Т. Н.

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