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GMAW...I've got something to say.

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  • GMAW...I've got something to say.

    First and foremost...I read a post about a Miller machine and problems trying to weld with a .023 diameter wire. It included something about Wire Feed Speed converted to amperage...?
    Could someone do their best to explain to me where they learned about stuff like that and then what purpose it serves or served them?

    Secondly...In my opinion, and seemingly shared by the confusion of the poster on what it meant exactly, In my head, that is the equivalent to saying in a practical sense, that if that was a continuous spool of spaghetti we were squirting into some one mouth, stuffing more in by increasing wire feed speed, seemingly he can chew and swallow, has to be so because the wire is smaller??? That sounds kind of wacked?

    I'd like to share some more of my musings on this... make of it what you will?

    If I took an eye dropper amount of water and poured it down the length of vertical rods of varying sizes, 1/8", 1/4", 3/8", 1/2", 5/8", 3/4". The same amount of water, which rod would release more drops off the end? Which would do it the quickest? Which drop would grow the largest before it fell?

    Now...if those rods were cotton wicks of varying sizes, and identical matches were lit and placed below the ends of the wicks at the same distance from the match, which would burn quicker, faster or hotter?

    I've got strong hands. Grip strength is still good. But my grandkids hands at 5 years old hold little size or strength compared to mine. If we put our respective hands around a neck and squeezed, the length of time and forced used over a period of time could have the same effect depending on the size of the neck.

    I hear fireman going to a fire slide down a pole, but returning to the station they usually used the stairs to get back up?

    At the top of the mountain low dense clouds usually form mist and light rain, in the valley dark clouds higher up bring winds, heavy rain and bigger drops.

    If I'm going to blow up a bridge and go looking for a fuse, do I need a thick fuse or a thin fuse if the distance is the same I'll be hiding from the blast?

    In the short circuit mode of metal transfer the wire comes out and hits the plate, current surges (slope), the end of the wire heats up. Small droplets or big droplets is resulting from the time it takes to reach maximum current values (inductance). Because it's being continuously fed, as the wire heats up magnetic fields squeeze and pinch the droplet off. Over and over. With formation of a droplet and the size of the droplet affected by a number of variables, one thing to ponder again is how the diameter of the wire effect those variables.

    Since steel becomes non magnetic when heated, and a magnetic field is required to pinch the droplet, doesn't it make sense then that on a small diameter wire it's going to heat quicker with more droplets so increasing wire feed speed kind of defeats that purpose?

    Finally, because some of you may be wondering where this is going, I'm going to say it's going now where fast. Multitasking on a Sunday I lost my train of thought on the matter and quite frankly doubt it matters anyways? But I'm left to wonder, converting WFS to amperage, what's up with that?

  • #2
    If we can't measure and convert things, then we can't have a relationship with it.

    In the fall a tree will lose it's leaves, yet it still grows tall and proud.


    • #3
      Current affects penetration/depth of fusion, plus some of us like to know what current we may be running at or need to produce in order to accomplish a certain weld. Other than that the conversion is simply more info in ones tool box. Some folks don't care.


      • #4
        Good relationships start with acceptance.
        Genuine relationships work because of understanding. I think I heard that some where???

        I live on a street lined with Elms, seeds in the spring leaves in the fall. Gutters 4 times a year. When a trees been pruned, that cleaning allows for more sunlight, better growth and more to rake when they fall. Tall and proud yes, but year after year more work.
        What's the relationship, leaf to branch or branch to leaf?

        Attaching an amperage value to WFS is akin to looking at the leaves on a tree and saying you need this many bags so for that reason I question it's value other then confusion in it's attempt to be meaningful as far as information goes.

        18 bags if anything like last year. Up as high as 26 maybe 14 depending on how the wind blows and from what direction.

        In my opinion... WFS is a dial that makes the wire move faster or slower out the end of the gun. Not up or down, just faster or slower, with a mixture of choke and starve to complicate things.
        Trying to convert wire size to necessary amps is akin to counting leaves on a tree. Subject to change depending on conditions.

        One might ask, if the noddle is thinner does it need hotter water to cook? Or if the pot of boiling water is the same, which noodle spends less time in it before it is cooked?


        • #5
          The water in the river is low......


          • #6
            ...but you’re asking about the burn off of the wire.

            ....and the correct response’s always low in the summer time.


            • #7
              [QUOTE=Sandy;n590795]Current affects penetration/depth of fusion, plus some of us like to know what current we may be running at or need to produce in order to accomplish a certain weld. Other than that the conversion is simply more info in ones tool box. Some folks don't care.

              Well... I agree with you up to a point, but that stops after the word fusion and box.
              I'm still not seeing the value to you. Sure, like the chart under the machines cover, the digitally displayed value of WFS becomes a quick fix number that for you, and others is a sweet spot maybe? But it's not amperage.

              I'm not saying in certain circles, various application, a value for WFS hasn't been shown to be useful, but it's not an amperage dial.
              Relying on numbers off a digital display to make a correlation with a dial that speeds up or slows the wire down is fine, but you haven't actually explained why or how to me and relating it to penetration?
              That lost me by the fact excess wire speeds reduces penetration.

              If I'm going to poke someone in the eye with a noodle would they prefer hard and firm or soft and limp? Well the GMAW process is akin to putting the noodle in a pot of boiling water at a rate where the water cooks it to pleasant degree of firmness. Continually. In tiny little chunks. The speed the wire continues into the water if increased will not cook the noodle fast but result in more of it being in the water, not making it cook quicker rather it cools the water off?

              As far as a base setting, assuming your running off a digital display, I can make that real easy, Match volts to WFS. 16 volts set 160 inches per minute on the dial for WFS, done and close with out account for material thickness, position, operator skill and volume of metal being deposited or the stick out/ electrode extension. I should throw the shielding gas into the mix and it's relationship to nozzle size and the other factors I mentioned and it then effects seriously the penetration. Because Arc voltage comes into play. Failing to mention it, gun angle and inclination, speed of travel and wire location In the weld pool, which all affect penetration, would be a disservice.

              I'm going to say though, if it works for you fantastic.


              • #8
                When wfs is increased, the current increases. At a constant wfs, an increase in wire diameter relates an increase in current. Or says esab. What would they know?


                • #9
                  About the only time I use amp figures on a mig machine is the rating of the machine.
                  I doesn't enter into my thinking when I need to weld 2 things together.
                  I don't contemplate volts much when I use my tig welders either.
                  If I was purchasing a dedicated machine for a singular production run one might care about the finest of the details.
                  In my world.....settings change with every task several times each day. I'll leave that tough stuff to Miller and the mathematicians.

                  Miller Dynasty 700...OH YEA BABY!!
                  MM 350P...PULSE SPRAYIN' MONSTER
                  Miller Dynasty 280 with AC independent expansion card
                  Miller Dynasty 200 DX "Blue Lightning"

                  Miller Bobcat 225 NT (what I began my present Biz with!)
                  Miller 30-A Spoolgun
                  Miller WC-115-A
                  Miller Spectrum 300
                  Miller 225 Thunderbolt (my first machine bought new 1980)
                  Miller Digital Elite Titanium 9400


                  • #10
                    "When wfs is increased, the current increases."

                    Supposedly...but with blind faith in belief how do you support that statement? If using a Millermatic 130 as an example, based on in put you get out put. High volts and low amps convert to high amps low volts. Short circuit metal transfer occurs around 14 volts up to 18 volts. The volt/amp curve relationship suggests for X number of volts you can only get x number of amps. Again, the welder self adjusts amperage within a range based on the voltage out put which is constant. Switch from a .023 to .030 wire with out changing anything else will do little more then change the amount of short circuits that occur.

                    "At a constant wfs, an increase in wire diameter relates an increase in current. Or says esab. What would they know?"

                    Ok...but in context to that statement, increasing the wire size means it will require more time for the extra wire to melt as much as it may require a greater current value to melt faster. This is where slope and inductance come into play as well the amount of short circuits per second. As far as ESAB and what they know, I'm going to say lots. Same as Miller, same as Lincoln. However, what they say, and how it's understood is the problem. They state this and they state that but it's up to you and me to make sense of it and it seems that's harder to do then you might think?

                    "In my world.....settings change with every task several times each day. I'll leave that tough stuff to Miller and the mathematicians."

                    My world as well. I'm not lost to the complicated nature of the beast that modern technology has made so easy for mastering. Years ago my instructor would say if you had too scratch a mark on the dial to show your favorite setting then you didn't learn enough in understanding what your doing when your doing it. It won't stop you from doing it, but it makes it harder. So we wrote things down on a note pad. Those that didn't choose to learn relied heavily on those notes and if they didn't bring the pad they ended up lost and explained poor performance on the machine, the feeder, the wire, the shielding gas, contact tip and no note pad. I think we can agree the setting chart under the cover it's not gospel it's a guideline.

                    One more comment before I drop the mic and move on. There are a lot of excellent resources available to help bring about a degree of understanding on the complicated process of GMAW. The failure is they don't or rarely do they explain how it applies. Maybe that's higher learning?
                    Knowing isn't enough, one must still apply knowledge to be successful with consistency.

                    In my opinion, not that's it's worth much, if the foundation has cracks, how well is the house of knowledge being supported? Maybe it's time to rethink how we go about explaining this stuff with a greater emphasis on how it applies?
                    The adage of no bad students just bad teaches comes to mind.


                    • #11
                      I guess I don’t really know what you’re asking then. Amperage on a wire feed is not something on a dial. Far beyond what I get into, but it’s just electrical theory and assuming all things are constant, such as on a line graph where voltage/amperage curves are explained. As far as the graph goes, it’s just a visual representation trying to make dummies like me understand the relationship between the two. Voltage is what controls the length of the arc for the little magic pixies to jump across. Amperage is how hot that arc is. So my best guess is...linguini.


                      • #12
                        Linguini works.
                        And the Magic of pixies jumping across the arc, that's priceless. I'm keeping that image for another day, thank you, I will use it.

                        What am I asking? Good question?
                        I'm asking who doesn't see what they are going to be welding, crack a bottle, flip the switch, turn a couple of dials and good to go, and who takes out the sheet of paper does some math and say's that how the number add up? Also if the latter, where did they learn to do it and why?
                        I grew up before digital display, maybe that's the problem? Old and out of date? Well that and poor math scores.

                        I see that if the gun is fixed to a track and all it did was mover forward at a consistent rate, if all that was increased was changing of the WFS one increment at a time, what would happen and why in explanations it occurs depending on wire diameter? I wouldn't be changing amperage.

                        That graph... If you got 100 pieces to a puzzle and your missing one piece to complete the picture, one from the corner would be a better one to lose then one from the middle.
                        Depending on the picture, you could lose plenty more pieces and it would make no difference in identifying what's in the picture but it's still missing pieces.

                        My original comment was regarding .023 and converting WFS to amperage required based on wire size?
                        I'm curious though... if someone is doing calculations, how does an inductance dial get explained?


                        • #13
                          Not my words, just quoting.

                          "The wire feed speed is in direct relation to the amperage at a given wire stickout (length of wire from the contact tip to the arc). The voltage is in the case of a CV (wire welder) the constant and is the length of the arc from the end of the wire to the weld pool, as you change the wire stick out the amperage changes to maintain the weld voltage. A normal wire stick out for short circuit mig welding is 1/4".

                          The following example may help you understand this with .035 ER70S-6 wire and C25 shield gas set at 20 SCFH flow.
                          1/4" wire stickout, volts 17 and wire feed speed 150 IPM = 100 amps
                          3/8" wire stickout, volts 17 and wire feed speed 150 IPM = 50-60 amps due to the resistive heating of the wire between the tip and the arc the weld current drops to the level required to maintain the set voltage.
                          If you were to reduce the stickout to 1/8" the weld current would increase to approximatly 150 amps to maintain the set voltage.

                          Typical min and max ranges of each wire diameter for ER70S-6

                          .024 minimum 30A 15V 105 IPM WFS, maximum 150A 21V 710 IPM WFS
                          optimum vert. setting 80A 18V 310 IPM WFS
                          optimum horiz. setting 110A 21V 465 IPM WFS

                          .030 minimum 50A 17V 95 IPM WFS, maximum 200A 23V 600 IPM WFS
                          optimum vert. setting 100A 18V 235 IPM WFS
                          optimum horiz. setting 150A 20V 385 IPM WFS

                          .035 minimum 50A 18V 75 IPM WFS, maximum 225A 25V 500 IPM WFS
                          optimum vert. setting 150A 18V 185 IPM WFS
                          optimum horiz. setting 215A 22V 415 IPM WFS

                          I hope this helps more than confuses you."
                          Ed Conley
                          Passport Plus w/Spool Gun
                          Miller 125c Plasma 120v
                          O/A set
                          SO 2020 Bender
                          You can call me Bacchus


                          • #14

                            Ohm's Law - Resistance is basic to electrical theory and to understand thisprinciple, we must know the Ohm's Law, which is stated as follows: In any electrical circuit,the current flow in amperes is directly proportional to the circuit voltage applied and in-versely proportional to the circuit resistance. Directly proportional means that even thoughthe voltage and amperage may change, the ratio of their relationship will not. For example,if we have a circuit of one volt and three amps, we say the ratio is one to three. Now if weincrease the volts to three, our amperage will increase proportionately to nine amps. As can be seen, even though the voltage and amperage changed in numerical value, theirratio did not.

                            The term "inversely proportional" simply means that if the resistance is doubled, the current will be reduced to one-half. Ohm's Law can be stated mathematicallywith this equation:I = E
                            Ed Conley
                            Passport Plus w/Spool Gun
                            Miller 125c Plasma 120v
                            O/A set
                            SO 2020 Bender
                            You can call me Bacchus


                            • #15
                              Well it didn't quite transfer

                              but this also:

                              The theory of electrical resistance is of great importance in the arc weldingprocess for it is this resistance in the air space between the electrode and the base metalthat contributes to the transfer of electrical energy to heat energy. As voltage forces theelectrons to move faster, the energy they generate is partially used to overcome theresistance created by the arc gap. This energy becomes evident as heat. In the weldingprocess, the temperature increases to the point where it brings metals to a molten state.

                              Ed Conley
                              Passport Plus w/Spool Gun
                              Miller 125c Plasma 120v
                              O/A set
                              SO 2020 Bender
                              You can call me Bacchus