TIG and MIG pulsed frequency?

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Hi Ed-

Any help you can give would be greatly appreciated. I am a Welding Instructor at South Seattle Community College, specializing in TIG.

I need to find a guide to use of a pulsed in MIG (GMAW) and TIG (GTAW). We have several TIG machines with pulsed at school, but no info on
proper settings. Somewhere there has to be some guide to this info to optimize the use of a pulser. Any help would be greatly appreciated.

By the way I am greatly disappointed in MIller and Thermal Arc, these companies sold us the MIG and TIG pulsed equipment . They went to great lengths to sell everybody on the wonders of Pulsed TIG without telling us how to use the damn things.

I have used the pulsed mode on several TIG welds and have gotten good results, but I am simply guessing as to settings. This seems ludicrous.
I grew up at Purdue University where my father was head of the Industrial Engineering school for 15 years. That taught me that there
are engineers who have answers to almost every question imaginable. I just need to find the right engineer, or the right books.

Thanks in Advance for any possible assistance
Ernie Leimkuhler
Stagesmith Productions
Renton, WA

“TO PULSE OR NOT TO PULSE” Shakespeare would be amused. Ernie your question opens up a bottomless pit of application, process and equipment issues. As power source electronics evolve with the seasons, the potential to add to and provide greater control of pulsed welding data increases in proportion.

Adding the electronics necessary for pulsed can increase the power source price by 2 to 5 hundred percent. With the large price differential of traditional and pulsed equipment , a key issue for anyone considering purchasing pulsed equipment would be, are the higher costs of the pulsed electronics justified for the intended TIG or MIG application?

Unfortunately the often “oversold pulsed feature” on MIG or TIG equipment is often offered to the welding industry as the ultimate process solution to all welding issues. The weld reality for the majority of carbon steels, low alloy or stainless applications, is pulsed and all its parameters variable combinations will offer minimal practical weld quality or production benefits in contrast to traditional, none pulsed MIG welding equipment and consumables such as all position flux cored electrodes. By the way I TIG welded in a nuclear research facility for several years and never used pulsed TIG equipment but still achieved the necessary weld code quality requirements.

A prime benefit of pulsing the arc and applying varaible pulsed parameters is found when welding nickel (sluggish alloys) or thin gage aluminum, “heat sensitive” applications. For example when MIG welding the corner edge of a thin, 0.075 aluminum box, using traditional open arc spray transfer, the arc and weld would be too hot resulting in burn through. If we used MIG short circuit for the same application, possibly the poor arc oxide cleaning action and the weld cosmetic appearance would not be acceptable. With pulsed MIG we can attain the cleaning action of spray with lower arc energy. Using TIG on the same aluminum application we could possible fuse the edge of the box without filler metal. However if we pulsed this application we would reduce the opportunity for weld burn through.

Its interesting to compare the low weld deposition rate of the traditional short circuit MIG mode with open arc MIG pulsed transfer. The short circuit mode is similar to pulsed, in that the short circuit arc, depending on the wire feed and voltage selected will go on and off typically from 75 to 150 short circuits per second. In contrast with an 0.035 (1mm), carbon steel MIG wire, the optimum pulse frequency range is typically 100 to 180 hz, while the higher weld deposition rate of the 0.045 (1.2mm) wire requires a higher pulsed rate of 130 to 260 hz. With aluminum welding using a 1.2 mm electrode, (lower weld deposition rates) than the equiverlent carbon steel wires, the required pulsed frequency would be 120 to 160 pulses per second. For an optimum pulse start point with the common elctrode wires mentioned select from the middle of the range. From this data we can see the relationship of wire feed rates , “weld deposition rate” and required pulsed frequency.

As we all know when manual TIG welding the weld deposition rate will be very low. If you watch the TIG welder he may push the TIG electrode into the weld pool creating a pulse effect on average 1 to 5 times per-second. If we were to automate the TIG wire feed rate, a pulsed rate of 3 to 20 hz will normally provide the weld we are looking for. With pulsed if you want more energy increase and for less energy and a quicker freezing weld decrease. Of course other pulsed welding variables will have a dramatic impact on the energy provided to the pulsed weld. The peak and background current, the pulsed width (pulsed time), the upslope and down slope time. The bottom line if the weld or electrode type does not require pulsed, and in most instances they don’t, “switch the pulsed mode off”. If the weld requires pulsed and the weld is too hot a reduction of the pulsed rate and any pulsed parameter will reduce the arc energy. My MIG training book titled “ Manual and Robotic Gas Metal Arc Welding” deals with this subject, information at http://www.weldreality.com

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