If you are interested in purchasing a plasma, one of the first “investments” you will need besides a capable air compressor, is a good quality dryer to remove moisture from the compressor air. Moisture is the arch enemy of plasma cutting. Plasma cutting with moisture in the line can yield disastrous results! Symptoms of having moisture in the line include poor cut quality with snootiness, and angularity of cut, sputtering, quickly worn consumables, and possibly even a destroyed torch.
Most companies provide a fine micron filter with a water trap as a last ditch effort to catch slugs of water or dirt that may travel down the line, but do precious little for actually removing large amounts of water from the air supply. It is surprising how much consumable life can be affected. It can also affect torch life by creating hot spots or arcing within the torch head where it should not be arcing. Trying to keep the moisture down to 0 is a multi layered challenge. First tank moisture should be eliminated from the tank daily by draining it. Also, any lines and hoses should keep well maintained fittings, so that leaks, and condensation are kept at a minimum.
At the tank, it is recommended to have at least a water trap dryer at the exit. The line should then travel as straight and short of a path to the plasma cutter as possible. Use of a desiccant type drier, that you’d find in an automotive paint supply store is a good way to get started with your dryer system. These are economical, and disposable. More expensive types use a replaceable silica gel pellets that soaks up moisture, and changes color as it does so to alert the user to the need to replace the pellets. Replaceable filter element types such as Motor Guard’s plasma cutter filter, are long lasting, and economical while providing excellent protection.
These have a high initial purchase cost, but are worth the investment if you have the money to spend. These filters should be right before the air supply enters the plasma cutter for maximum protection. New or dedicated hoses should always be used as well, to keep moisture out of the system when the plasma cutter is installed. Existing hoses typically have large amounts of water in the line, just waiting to dislodge and travel through the plasma cutter.
A more modern approach to starting an arc is the use of “blow back” technology. This technology uses a dead short where a spring loaded electrode is firmly seated against the nozzle face and air pressure is applied to the torch. The air pressure pushes the electrode back so the air can escape from the nozzle hole. Simultaneously, electricity begins to flow creating a spark between the nozzle which is grounded back through the machine to complete the circuit, and the electrode. This ionizes the air, and a low amperage plasma arc is established. This design automatically includes a pilot arc. It cannot work unless there is a complete circuite within the torch head. This start type poses no threat to surrounding electronics, or to the machine itself. It can be a little slower start than the HF style, but most people see little or no difference. Some disadvantage exists in the fact that occasionally the arc won’t start, but usually only in very rare cases. Most major companies utilize this style start under 100 amps. The inherent design creates problems for use in plasma cutters greater than 100 amps, however. An advantage of this design is that there are no high frequency points to maintain, and the start style is very friendly and can be used in sensitive areas. Most people after using both blow back and High Frequency start styles, find little practical difference in regular cutting. However, regardless of the start style, the pilot arc is usually the thing that most people feel they cannot live without. A blowback torch consists of moving parts, but usually, life span is nearly that of a High Frequency torch. But it is usually considerably more expensive for the blowback torch than a High Frequency torch, should one need to be replaced. The Blowback style does typically have more parts, and is more sensitive to any small variation in improperly set parameters, especially air pressure.
Spot welding is a great form of resistance welding, which is a technique of welding two or more metal sheets jointly without by means of any filler material by pertaining pressure and heat to the area to be welded.
Spot welding is one such technique that is usually used to bond metals shaped into sheets that is not thicker than 3 millimeters. Just like any other welding technique even spot welding can produce clear-cut bonds without making excessive heating that can have an effect on the properties of the leftover sheets. This is pulled off by setting free a huge amount of energy in a short time in order to produce restricted and consistent welds. When it comes to galvanized steel then higher levels of current is required.
Tungsten inert gas (tig) is often used for high-quality precision welding purposes. In this particular process an arc is formed between the metal and the permanent non-melting tungsten electrode. With the help of the torch the gas is fed, thereby it shields the electrode and molten weld pool. In case of usage of filler material, they are added discretely to the weld pool.
There are several benefits of tig welding and it takes into consideration finer quality welds, clear-cut control of welding variables such as heat, independence of spatters and low warp. Moreover, it can be used at lower amperages for thinner metals and they can be used on exotic metals.
It can be used on different types of metals, but most commonly aluminum is used in particular metals of a smaller thickness.
Almost all types of metals can be tig welded but the most recurrent metal that is associated with this type of welding process is the aluminum, predominantly smaller thickness metals. Even though there are several other set of processes that allows joining aluminum, tig is one such process that is most applicable in the case of lighter gauges.
On the whole, as a rule, the gas tungsten arc welding process is best for repairing aluminum.
