Pulse Tig

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I am anxously awaiting my Acrmaster 185 TSW.  I printed and read the manual, I also read the book by miller some one kindly posted the link to.Balance:  Amount of + and - in a ratio of %.  More negative puts more penatration, more + is more cleaning.Frequency:  More means narrower cone of heat.Pulse?  I don't get it.TIADavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:well good luck with your new tig welder and as far as any info i can not give you any cause i have very little tig experience. but i would like to know what pulse means to.
Reply:Originally Posted by David RI am anxously awaiting my Acrmaster 185 TSW.  I printed and read the manual, I also read the book by miller some one kindly posted the link to.Balance:  Amount of + and - in a ratio of %.  More negative puts more penatration, more + is more cleaning.Frequency:  More means narrower cone of heat.Pulse?  I don't get it.TIADavid
Reply:Don't know how I described it previously, but here's what came to mind today.For pulse TIG on your machine, you set peak current (Ipk), background current (Ibk), pulse frequency (f), and percent peak time (tpk).One reason to pulse is to produce the "stack of dimes" look of overlapping spot welds.  You set Ipk and tpk to melt a spot, and set Ibk low to allow the spot to cool and partially solidify.  You want to overlap the spot welds by about 70% minimum, so that the penetration is constant and not rippled (deep/shallow).  The speed of pulsing, pulses per second, is the frequency, and for hand welding, a pulse frequency of around 1 pps is slow enough to match the travel speed and produce spots that overlap the desired 70% minimum.  With low frequency pulsing, you can dip your filler metal in sequence with the peak pulse.Pulsing is also commonly used for precision tube and pipe welding, since the alternating melt and cool sequence allows vertical and overhead welding without spilling the puddle on the floor.Pulsing also has the effect of keeping the edges of the weld very uniform and consistent.  Some times the puddle on a constant current weld will wander around a bit an the weld will end up kind of wavy or snakey.  With pulsing, the puddle partially solidifies during each background current pulse, and it doesn't have a chance to wander around.For a very radical pulse, the peak current can be set very high, like 300 amps, provided the % time at peak is very short, like 5 or 10%.  Since the time is peak is so short, the tungsten can handle very high current.As an example, if f = 1pps, %tpk = 10, Ipk = 300, Ibk = 5, then the peak time would be 1 x 10% = 0.1 second, background time would be 1 - 0.1 = 0.9 second.  And the average current (Iavg) would be (10% x 300) + (90% x 5) = 34.5 amps.  Generally, with a radical pulse like this example, the average current required to get full penetration is substantially less than the same constant current weld.  This radical pulse may penetrate 0.050 to 0.060 inch (just guessing), where as it may take 50 amps constant current for the same thickness.I'm currently doing a full penetration pulse TIG machine weld on 1/8" 304 SS tubing, where the tube is rotated beneath a fixed torch.  The parameters are Ipk = 200 amps, Ibk = 20amps, f = 3 pps, %Tpk = 50%, travel = 5.5 ipm.  I may have gone more radical, higher Ipk/shorter Tpk, but on this power supply the %tpk is not adjustable, its internally fixed at 50%.  This pulsing is fairly fast for this travel speed an produces a tightly spaced ripple pattern about 90% overlapped.Go to Pro-Fusion to play with a pulse calculator.  The terms they use for the settings are different than your machine, but it's the same principle.http://www.pro-fusiononline.com/welding/pulseparams.asp
Reply:Thank you verry much pulser.DavidReal world weldin.  When I grow up I want to be a tig weldor.