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RECENT PROCESS ADVANCES

The use of microprocessors allowed ESAB to recently introduce a MIG welder called QSET.^TM  A difficult  training task is instructing someone to set up  Short Circuiting GMAW (MIG "Short Arc.")  ESAB introduced this product that automatically sets the correct welding parameters for a given wire/gas combination.

The welding operator selects the wire feed speed and welding machine sets the proper "short arc conditions.  There are no synergic lines, just a single knob to set the wire feed speed and obtain the optimum welding parameters. The welder can still elect to modify arc length by means of a voltage trim control.  A further benefit of system is that the control algorithms maintain a constant power in the arc and depth of penetration, even if the contact tip distance changes. Because the arc stability is closely controlled, there is also less weld spatter and, therefore, less post-weld cleaning.

ESAB explains that in a stable "Short Arc" process the ratio of short circuit and arc time lies in a narrow range.  The QSET welder continually measures and controls the short circuit pattern.  A test weld is made and in a few seconds the welding machine optimizes and maintains the optimum conditions.  Maintaining the proper "Short Arc" conditions is important to avoid cold welds or "cold lap" as it is often referred.

Another recent advance if the use of Tandem MIG.  Although versions of this process were patented as early as 1957, little was done with the process until recently. Modern controls and power allow process variations that make these processes viable.

The use of multiple Tandem MIG systems for making circumferential welds in line pipe is very productive.

The early developers of MIG welding understood what was needed to properly deliver shielding gas such as the need for pressures on the inlet side of the gas solenoid being above 25 psi.  This was needed to have the gas flow remain at the  preset level when spatter built-up in the torch nozzle and the torch cable bent and twisted in operation.  However this created excess shielding gas stored in the delivery hose when welding stopped that was mostly wasted at the weld start.

Stauffer in 1982 patented a device ( patent figure left, Patent Number 4,341,237) to reduce this start surge.  He  also understood that some extra gas was needed at the start to quickly purge the torch nozzle weld start area or air.  He built an accumulator into his system that delivered the proper amount of extra start gas.  However his device used low pressure eliminating the automatic flow compensating feature and since the pressure was low the accumulator and therefore the device was quite large and complex.

A much similar and effective system (patent figure right) was developed that optimized the gas flow at the weld start.  It also eliminates the excess stored gas significantly reducing gas waste.  It still delivers a sufficient amount of gas at the weld start, at a flow rate that avoids excess turbulence, to purge air from the MIG gun nozzle and weld start area. It was patented by Uttrachi in 2003, Patent Number 6,610,957 (Hey that's me!)  Uttrachi had additional patents for other devices to reduce gas waste and improve weld start quality issued in 2006, Patent Numbers 7,015,412 and 7,019,248.

There are many innovations we have no doubt missed.  However by referencing the patents mentioned one can find substantially more patents and references that may be of interest.  Patents have the objective of teaching the reasons why something works.  A patent as a bargain between the Government and the inventor. The Government offers a short-term monopoly in return for a full description of the invention, which is published by the Patent Office. This exchange of a monopoly for a full description underpins the patent system and leads to published patent documents being the most comprehensive source of technical information in the world, for practically every area of technology.  That is why one obtains a limited time monopoly so the information is fully disclosed for posterity.  Some inventors do a better job than others of fully disclosing their insight into the product or process details.

REFERENCES

The references below give the student of MIG some base to search further so as not to have to reinvent the wheel, or worse conduct future research without knowing it was already invented!

1. "Controlling the Melting Rate and Metal Transfer in Gas-Shielded Metal-Arc Welding. Part II," by Al Lesnewich, Welding Journal 1958, 37(9), pp 418-s

2. "GMAW-A Versatile Process on the Move," by Kevin Lytte, Welding Journal, March 1983, pp15.

Some Other References Not Sited But Significant

1. "Controlling the Melting Rate and Metal Transfer in Gas-Shielded Metal-Arc Welding. Part I," by Al Lesnewich, Welding Journal 1958, 37(8), pp 343-s

2. "Characteristics of Inert Gas Shielded Metal Arcs," by Muller, Greene, and Rothschild, Welding Journal August 1952, pp 717-s

3. “Energy Distribution in Electric Welding,” by C. E. Jackson and A. E. Shrubsall,   Welding Journal, 29 (10) Research Supplement 520-a to 521a (1959).
4.  “Control of Penetration and Melting Ratio with Welding Technique,” by C. E. Jackson and A. E. Shrubsall,  The Welding Journal, 32 (4) Research Supplement 172-s to 178-s (1953).

5. "The Effect of I²RHeating on Electrode Melting Rate," by Wilson, Claussen and Jackson, Welding Journal, 1956, 35(1), pp 1-s

6. "The Inert Gas Shielded Metal Arc Welding Process" by Wooding, Welding Journal, 1953, 32(4,5); pp299-s, 407-s

7. "The Aicromatic Welding Process'" by Muller. Gibson, and Roper, Welding journal, 1950 29(6), pp 459-s

8. "Inert Gas Shielded Welding Arc Behavior and Metal Transfer Characteristics" by George Skinner and Yenni, Electric Arc and Resistance Welding, IV July 1954, American Institute of Electrical Engineers, Publication S-64, pp 16-27

9. "Arc and Bead Characteristics of the Aluminum Self Adjusting Arc," by Needham and Smith, 1958 British Welding Journal, 5, pp 66-76

10. "Carbon-Dioxide Shielded Consumable Electrode Arc Welding" by Rothschild, Welding Journal 1956, 35(1) pp 19-29

11.  "GMAW Shielding Gas Flow Control Systems" by G. D. Uttrachi, Welding Journal 2007, 86 (4) pp 22-23

Have a Welder?   Improve Weld Starts and Have Shielding Gas Cylinder Last at Least Twice as Long! 

Note: Our Patented GSS is Not Available in "Stores"

A home shop fabricator in Georgia with a Miller ^TM 175 amp welder purchased a 50 foot Gas Saver System ( GSS^TM ) so he could use a larger cylinder and mount it on the wall of his shop.  He wrote:

"The system works great.  Thanks for the professional service and a great product."   Click To See His Home Shop

A Professional Street Rod Builder Had This to Say:

With their standard MIG welder gas delivery hose the peak shielding flow at weld start was measured at 150 CFH. That caused air to be sucked into the gas stream causing poor weld starts.  With the GSS replacing their existing hose, the peak flow surge at the weld start was about 50 CFH.  Total gas use was cut in half.

Kyle Bond, President, quickly saw the improvement achieved in weld start quality as a significant advantage!   Kyle, an excellent automotive painter, was well aware of the effects of gas surge caused by pressure buildup in the delivery hose when stopped.  He has to deal with the visible effects in the air hose lines on the spray gun in his paint booth!  The paint surge is visible and creates defects unless the gun is triggered off the part being painted!  We can’t do that with our MIG gun!

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