Showing posts with label EHS. Show all posts
Showing posts with label EHS. Show all posts

Air Carbon-arc Gouging: A Fast and Efficient Way to Get Rid of Metal

Air Carbon-arc GougingIn metal working maintenance and repair, it is sometimes required to repair or replace a weld, or remove excess metal from a worn or defective part. A process called air carbon-arc (also known as air arc) gouging, developed in the 1940’s, has become a widely accepted method for metal working. Compared to grinding, chipping, and cutting, air arc gouging provides a much faster, more efficient, and more cost-effective means to remove unwanted metal.

Air carbon-arc gouging differs significantly from oxy-fuel cutting (OFC) and plasma cutting. Air carbon-arc does not require oxidation to maintain the cut and is able to be used on many kinds of metal. Air carbon-arc gouging cuts and removes metal by an electric arc created a carbon or graphite electrode as it is drawn along the target metal. As the arc melts the target metal, a steady, high velocity air stream blows the molten material out of the way. The arc is supported by a constant current power source. A compressed 60 to 100 psi gas source supplies the air stream. A special air arc torch is required, as it not only holds the electrodes, but has unidirectional air ports built in to direct the air stream.

Air carbon-arc gouging will work on any material that will conduct electricity and which can be melted by the electric arc, such as carbon steel, stainless steel, cast irons, and many copper alloys. Metal removal rate is controlled by increasing the gouger’s amperage, slowing down the movement of the electrode, and by the efficiency of the air stream. Most common uses for air arc gouging are cutting, removal of defective welds, removal of bolts, removal of rivets, making holes, and casting finishing.

If you have any questions about air carbon-arc gougers, contact:

6121 Airways Blvd.
Chattanooga, TN 37421
Phone # 423.424.0515
Fax # 423.424.0518

Demand Pulse MIG Welding

Demand Pulse MIG Welder
Demand Pulse MIG Welder
(courtesy of Aftek-EHS)

Demand Pulse is possible because of the MOSFET, an extremely fast electronic switch. Using constant current DC power, a wire is fed into the arc zone. As the wire approaches the work, the voltage drops as a function of the arc length. At a pre-selected arc voltage (usually 15 volts), the MOSFET fire a pulse of current to expel the tip of the wire across the arc gap. This current is supplied by means of a parallel resistor in the main current control circuit and is generally 100 amps. Switching time is measured in nanoseconds, and the total cycle time is very short, perhaps 15 nanoseconds. An inductor is not required, nor desired, since fast switching is essential. Perfectly tuned, the pulse cycles 200 times per second or slightly less.

The arc looks and sounds like “short-arc”, but a close look will show that there is no short-circuit. The arc length is from .020” to .090”, very short compared to GMAW-P done with conventional machines. This short arc length, combined with the short duration of the pulse, and the low current required to effect transfer gives a total arc “heat” far below that of either short-circuit transfer, or conventional GMAW-P. Fusion is excellent, because the arc never goes “out”.

Below is a demo video using this technology on 18 gauge stainless steel, without any burn through.

For more information contact:

2960 East State Street Ext.
Hamilton, NJ 08619
Phone # 609.588.0900
Fax # 609.588.8333