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  • Hand-operated electronic TIG amperage control

    I am considering designing a hand control for a TIG torch. I've purchased a couple of different hand controls that are out there, and frankly I'm disappointed in all of them. Basically they all suck in one way or another. Lack of a smooth on/off transition, and lack of precision being my chief complaints.

    I am proposing this because I am really not a welder by trade. I am a electronics and software engineer. So building a remote hand control is the type of thing I actually do for a living.

    The hand control I want to design would be a precision made remote amperage control that electronically regulates TIG welding current, and allows electronic start/stop of the welding current. The idea is to give the operator better control at the torch without needing a foot pedal for out of position welds.

    1. It would be weld-by-wire (ala fly-by-wire). That is, the knob that attaches to the TIG torch and rotates, would not be a potentiometer that regulates the welding current. Instead, the knob would be a precision rotary encoder that sends signals electronic signals to a small electronic control box located next to the welding machine. The control box reads these signals from the rotary encoder and adjusts the welding current electronically.

    2. The rotary encoder mounted on the TIG torch would be an industrial grade precision encoder with a resolution of 64 steps per revolution. Very smooth to turn, high precision, good feel and feedback through the knob.

    3. You would "push" the rotary encoder knob (push perpendicular to the rotating direction) to start and stop the torch. Push once to start, weld, push again to stop.

    4. The control box would have an electronic setting to adjust the initial percentage of amperage when the torch is first turned on. For example, suppose you set your welding machine to be at 200 amps. Then you might set the initial on-amperage of the control box to to 50%. With these settings, when you press the encoder knob to turn the torch on, it ramps immediately up to 100 amps (say in 1 second). Then you can turn the rotary encoder knob to increase and decrease the amperage from there.

    5. The control box would have an electronic setting to adjust the "step size" as a percentage of total amperage. The encoder has 64 steps per revolution, so you have to indicate a percentage of amperage-change for each 1/64th turn "step". For example, if you set a 1% step size, then you need roughly one and a half revolutions of the encoder knob to go from 0 amps to full amperage. This basically adjusts the "sensitivity" of the knob. You could adjust for high resolution/low sensitivity by setting it to 0.5% per step (3 full revolutions to go from 0 amps to full amperage). Or you could adjust for low resolution/high sensitivity by setting it to 2.0% per step (3/4 of a single rotation to go from 0 amps to full amperage).

    6. Because different manufacturers have different size potentiometers for remotely controlling weld current, there would be a different control box for each manufacturer of welder. Obviously, there would be a Miller, Lincoln, Hobart, etc., etc. However, the differences between manufacturers are so small, that maybe there would just be one style of control box, and there would just be an internal switch inside the control box to select the manufacturer of your welding machine.

    Do you think such a high-precision remote control device would be useful for TIG welding? I would love to own such a device. Does such a thing exist out there already? I could not find such a thing.
    miller dynasty 350
    miller spectrum 1000

  • #2
    I have always wanted a hand remote that was like a dead mans switch. Spring loaded depress to initiate the more you push the more amps when released would extinguish the arc.

    The only north south I have ever used were sliders that once set stayed and had to be moved manually back to extinguish.

    All the rest of your stuff was way over my head sorry just a dumb welder here.

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    • #3
      Yes there are quite a lot of them being used with simpler designs that work very well and they are not that expensive to buy.
      Cheers

      Comment


      • #4
        I had thought that I had wanted a N-S variable rocker switch, but after using my RMLS-14, I've found that as long as the output is set to the correct amperage the momentary rocker switch is just perfect.

        After finding this hand control, I stopped using my foot pedal and haven't really felt the need for variable control. Now I would if I was welding aluminum, but my Maxstar doesn't do aluminum.
        Last edited by tasslehawf; 02-10-2009, 11:53 PM.
        Miller Maxstar 200 DX
        RMLS-14 Momentary Hand Control
        Miller Syncrowave 180 SD
        Porter Cable 14" dry metal saw
        Hitachi 4.5" grinder
        http://mhayesdesign.com

        Comment


        • #5
          Wth the multitude of torch mounted controllers in the market, I really can't see the point of a pulsed encoder version. The simple cheap and effective voltage devider and micro switch will have to do for the foreseeable future,

          Comment


          • #6
            I have the CK Worldwide model with a band, it is awesome. Don't try to reengineer the wheel, I believe if you think about it your rotary encoder will suffer from the Hi freq bleed off. If it will mess with a Ipod I think it will mess with almost anything.

            Peace,
            Paul

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            • #7
              ok well i can see most people here are happy with the hand controls currently available. i find that they are all rather lacking for various reasons. on some i find that the on/off detent is too stiff, or on others they require too much finger rolling to get to the sweet spot amperage level.

              if i build one, i suppose it will just be one for myself.
              miller dynasty 350
              miller spectrum 1000

              Comment


              • #8
                Originally posted by ridesideways View Post
                ok well i can see most people here are happy with the hand controls currently available. i find that they are all rather lacking for various reasons. on some i find that the on/off detent is too stiff, or on others they require too much finger rolling to get to the sweet spot amperage level.

                if i build one, i suppose it will just be one for myself.
                ridesideways,
                Sound like you are quite sharp in the field of electronics. This may be too basic, but since you are going to build one for yourself, why not take that prototype to one of the trade shows and see if anyone is interested. All you have to lose is a little bit of time...and besides welding trade shows are fun.
                -
                Thanks Becky

                Miller Matic 210

                Syncrowave 250

                Lincoln Weld Pac 100

                Comment


                • #9
                  Everything you say you want to do is already on the miller diversion 165. A button to turn on by pushing once for on and push again to turn it off. And the amperage wheel can be set at the lowest point before clicking it on.
                  sigpic

                  Comment


                  • #10
                    Almost every machine put out nowadays is programable. Hit a momentary trigger, unit ramps up does its thing, hit the trigger again, unit ramps down.

                    Gone are the days of the sweet spot, besides a digital encoder would encounter HF problems galour. Run a tig close to a CNC programable shear, and the encoders do wild things.

                    Comment


                    • #11
                      Originally posted by ridesideways View Post
                      on some i find that the on/off detent is too stiff,
                      That just means it is new, after a few 50 hour weeks it's just right!!!
                      at home:
                      2012 325 Trailblazer EFI with Excel power
                      2007 302 Trailblazer with the Robin SOLD
                      2008 Suitcase 12RC
                      Spoolmatic 30A
                      WC-24
                      2009 Dynasty 200DX
                      2000 XMT 304
                      2008 Thermal Dynamics Cutmaster 52
                      Sold:MM130XP
                      Sold:MM 251
                      Sold:CST 280

                      at work:
                      Invision 350MP
                      Dynasty 350
                      Millermatic 350P
                      Retired:Shopmaster 300 with a HF-251

                      Comment


                      • #12
                        just getting ready to try one, I like the band Idea that Paul mentioned on the CK unit, but I also like the idea of a deadman switch mounted with velcro/ties so that it could be moved to best fit for individual preference. I have a couple fingers missing on my torch hand and so I am "a special needs Ole man PM me and we will work on one!

                        Tim
                        sigpicRetired Elevator Consrtructor Local 19 IUEC
                        AK bush pilot (no longer in AK) too old and no longer bold)
                        Chaplain CMA chapter 26
                        Dynasty200dx (new and loving it)
                        MM-252 (NEW AND LEARNING IT)
                        Hypertherm PM-45
                        Miller 140 mig 110v
                        Vtwin builder

                        Comment


                        • #13
                          I use a CK amptrak too. It ramps up just about right - fast enough so you don't have to move it far, but slow enough where you have fine control. They give you a couple different housing covers, so you can adjust where the track is exposed to suit your individual preference. upper track only, lower track only, or both sides exposed (two fingers). Track tension is adjustable too.

                          My only complaint is that the contacter is a little tight until you break them in. I disassembled mine and slightly bent up the microswitch contact on the sliding pot to lighten it up.
                          2007 Miller Dynasty 200 DX
                          2005 Miller Passport 180

                          Comment


                          • #14
                            MR57,

                            Thanks for the heads up, as I am definetly going to have one when I upgrade to a watercooled torch!

                            Looking for a Cooler now (or the details to build one) Just the time I am spending in the shop practicing the little WP-17 gets to darn hot to suit me! Especially doing any AL.

                            Tim
                            sigpicRetired Elevator Consrtructor Local 19 IUEC
                            AK bush pilot (no longer in AK) too old and no longer bold)
                            Chaplain CMA chapter 26
                            Dynasty200dx (new and loving it)
                            MM-252 (NEW AND LEARNING IT)
                            Hypertherm PM-45
                            Miller 140 mig 110v
                            Vtwin builder

                            Comment


                            • #15
                              Diversion 165

                              ok guys i have been working with diversion 165 for about a week now and must say it is a nice machine, the torch design is just amazing it has a very natural feel in my hands and everyone else that has tried in our shop, with the controls actually being built into the torch its a lot more ergonomic then the bulky tie on's that we are all used to,Weld craft out did themselves id love to see more torches with this design on the market, the question i have about your switch is how many revolutions till the control box opens to full power at 64 step per rev. having to turn the wheel forever to get to full power would really be kinda of bothersome, jmho

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