Generation of the Plasma Arc (2 Ways):

Plasma cutters produce the plasma in one of two ways: High-Frequency (HF) Contact or Pilot Arcs. Which one your plasma cutter uses depends on how old it is; the new high tech equipments use pilot arcs. The major dissimilarity is that HF Contact models have to close a circuit with a work piece that conducts electrical energy in order to cut while the pilot arc models can cut anything. They work in very different ways.

HF contact method of generating plasma is still found in low financial plan plasma cutters and in older plasma cutters. How it works is the plasma cutting component is connected to the work piece by a clamp and wire and when you touch the nozzle of the torch to the work piece an electric circuit is created. An electric arc zips from the work piece threw the plasma torch nozzle to the negative electrode inside the torch head. At the same time, pressurized inert gas runs in the opposite way, from the torch head out onto the work piece. As the gas surges past the zapping electric arc it is heated to around 50,000 degrees Celsius. At that heat the gas becomes plasma which is a form of matter that is a liquid and a gas at the same time. It is this super hot, super fast moving plasma that cuts the metal. The HF contact technique is said to contain one cycle since the major plasma flow is created in one step.

The Pilot Arc technique is a two cycle procedure. First, a high power, low amperage circuit is used to make a small, high intensity flash in the body of the torch which creates a small pocket of plasma in the torch head (note that the plasma is previously produced in the torch without the required to touch the work piece, this is what eliminates the require for a conducting work piece). Now, you can use a trigger to ignite the main plasma arc that will be used for cutting whatever it is you desire to cut. Pilot Arc is the technique used in CNC plasma cutting applications.

IMPACT OF ENGINEERING CONCEPTS IN WELDING

What is engineering? Engineering is a discipline where we apply technical, scientific and mathematical knowledge to implement and to design some machines, devices and structures. The power equipments and machines we use in the welding industry are the inventions of engineering concepts. Plasma cutter the equipment which cuts different types of metals has the in built structure which is made of electrical components and the electrical energy is converted in mechanical energy during the operation of the machine. All other welding products such as mig, tig, wire feeders and water coolers are the child of engineering concepts. Silent diesel generators the alternative source of power supply is also an invention of engineering concepts. In generators the electrical energy is converted into mechanical energy. In welding torches the gas which flows is controlled by a gas valves is a mechanical engineering concept which follows some mechanics.

Arc welding process and its equipments

Welding is regularly used for the permutation processes i.e. arc, resistance, laser, electron beam, stud and orbital welding.

Weld controllers are necessary to help the processes used by these tools. Welding equipments also work as aid to welding control source. There are also wide-ranging system to cutting machine, torch, feeders, cables, robots and feeders.

Arc welding process and welding machines

Arc welding is utilizing welding power supply to produce an electric arc between the base material and an electrode, for melting the metals at welding point. Arc welding equipments can use and direct current or alternating current, and consumable or non-consumable electrodes. Shielding gas guards welding region using some inert or semi-inert gas and evaporate wadding material. The process of arc welding is broadly known for low capital and running costs.

MIG and TIG welding are the two common specifications of Arc Welding. MIG is also acronym as MAG (metal active gas welding) and known as one of the mostly popular arc welding process. MIG welding equipments uses in different kinds of gas like pure carbon dioxide, argon gas and some time merge of both to complete the process.

Plasma Arc Cutter Operating Procedures

To activate the plasma arc cutter make sure the air pressure is sufficiently around 70 p.s.i. for most plasma arc cutter units and the ground clamp is attached to the work piece.

Turn the plasma arc cutter on and adjust the amperage the manufacturers specifications for the thickness of metal to be cut.

Position the shielding cup over the metal, press the igniter button and allow the arc to become established. Next, move the arc over the cut line and make the cut.

The thicker the metal the slower the travel speed must be to get a good cut and vice versa. The quality of the cut usually decreases as the metal thickness increases and the travel speed decreases.

A guide bar may be used to help achieve good straight cuts.

The shielding cup and constricting nozzle should be held approximately 1/8" to 1/4" above the metal being cut. The operator should avoid dragging the constricting nozzle and shielding cup on the metal when making the cut unless they are specifically designed to touch the base metal while cutting.

Always make cuts on the waste side of the cut line.

Avoid cutting with the plasma arc cutter in damp or wet locations. The hazards of electrical stock greatly increased.

If plasma arc cutting over an open barrel with a grate be aware that the fume plume will be directed back toward the operator. Avoid this condition if at all possible, otherwise limit the exposure to fumes to short duration's.

Cuts with the plasma arc cutter may be made by moving forward, backward, or sideways. Determine which direction is easiest for you and use that procedure as often as possible.

Always move the plasma arc cutter (PAC) as fast as possible when making a cut. This increases time efficiency , improves the cut quality, and reduces the build up of dross.

Compressed air used in plasma arc cutter should be dry or the cutter will not yield a quality cut or it not cut at all. An auxiliary air filter may be place in the compressed air line to condition the air for a plasma arc cutter.

Always turn the plasma arc cutter off before laying the torch down and leaving the work area.

If the quality of the cut deteriorates to an unacceptable level either the constricting nozzle, the electrode, or both may need to be changed. The electrode on most plasma arc cutter will have a life of about twice the life of the constriction nozzle. Keep a supply of constricting nozzles and electrodes on hand as they deteriorate quickly during continuous use. Turn the plasma arc cutter off to put on replacement parts.

Keep the plasma arc cutter torch leads and ground lead stored so they will not be cut or damaged when not in use.