Plasma Arc Welding Advantages and Limitations

Jun 4, 2013

Industrial robots are able to do a variety of welding tasks including plasma arc welding. Plasma arc welding is an extension of gas metal tungsten welding that produces an amazing amount of control and quality product.

Sim­i­lar to TIG weld­ing process­es, plas­ma arc weld­ing (PAW) pro­vides a high qual­i­ty method to join­ing met­al parts.

Prin­ci­ples of PAW

Plas­ma arc weld­ing is basi­cal­ly an exten­sion of gas met­al tung­sten weld­ing (GMAW or TIG). Both weld­ing process­es gen­er­al­ly use non­con­sum­able tung­sten elec­trodes to car­ry pow­er to the weld­ing torch and into the ori­fice gas. The ori­fice gas rep­re­sents much of what is dif­fer­ent about the GMAW weld­ing process and the PAW weld­ing process. The design of a PAW torch allows for the ori­fice gas to build up in a cham­ber at the end of the torch. The arc heats up the ori­fice gas to near­ly 30,000 degrees Fahren­heit. At this point, the ori­fice gas turns to plas­ma and is expelled through a nar­row open­ing at the end of the weld­ing torch. As in GMAW, a shield­ing gas sur­round the weld pool to cre­ate an inert envi­ron­ment to keep the weld pool clean and free from oxy­gen that will rust the metal.

Advan­tages and Limitations

The main advan­tage of plas­ma weld­ing lies in the con­trol and qual­i­ty pro­duced in the part being weld­ed. The torch design allows for bet­ter con­trol of the arc, as well as a high­er tol­er­ance for in torch stand­off distance. 

Welds are typ­i­cal­ly clean­er and smoother when using the PAW process. Small­er heat-affec­t­ed zones result in welds that are very strong and less notice­able, which is impor­tant for some parts.

A major lim­i­ta­tion in imple­ment­ing a plas­ma weld­ing process is the rel­a­tive­ly high start­up costs. Plas­ma weld­ing equip­ment tends to be expen­sive. Because it is a more spe­cial­ized weld­ing process, the train­ing and exper­tise required is also more intense.

PAW and Indus­tri­al Robots

Robots​.com offers a vari­ety of plas­ma weld­ing robots from var­i­ous top brands. Any of these man­u­fac­tur­ers’ arc weld­ing robot arms can han­dle a plas­ma arc weld­ing dres­sout pack­age. Fanuc’s ARC Mate 120i and Motoman’s EA1400 robot arms are exam­ples of these robots.

To learn more about automat­ing your plas­ma weld­ing tasks with an indus­tri­al robot, con­tact experts online at 8777626881.

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