Automated Orbital Mig - Profile problem

  1. GavJ Member

    Glasgow Scotland
    Hi All, i got dragged into our shop today at work as they were having issues with a automated welder. It's used to weld branches or outlets on pipe work. It's quite an old set up but all seems to be functioning well apart from the weld profile on the finished article. At the top of the weld, lets call it 12 0'clock the profile is fine, but at 3 & 9 o'clock its not. Best way I can describe it is its "muffin top"

    Ive havent been professionally welding for about 20 yrs but then again this machine must be as old if not older, I just can work out what I want to do to improve the profile. If I was manually welding I would change the angle of the torch at these points but that's not an option with the setup we have. What I can do is;
    Change the pass speed
    Change the weave amount
    Change the amperage
    Change the distance the torch is from the work piece
    Change the wire speed

    Where should I start? I tried a few of the above today but it didn't improve matters.

    I cut open one of the welds and although I would have preferred some more penetration the throat thickness was fine, It will be holding 15 bar of water and I would say it was what I used to refer to as a class II weld, not penetrated but no porosity and throat thickness as wide as the pipe wall thickness. Is this as good as it gets with this set up Am I expecting to much from an robotic weld?
    • 5.jpg
    • 7.jpg
    • 2.jpg
  2. Jlg

    Jlg Member

    If it's the part that sticks up in 3rd pic it looks like not hot enough
  3. Ruffian Member

    Devon UK
    It looks to me like if you put tiny bit more gap between the 2 pieces then may penetrate better.

    Looks like it is struggling to get a full penetraton and standing proud.
  4. Brad93

    Brad93 M J B Engineering

    Needs to be much hotter
  5. chris y Member

    Durham England
    Was it better, and now its different?

    If so did anything change, or may anything have changed that you dont know about? Could someone have been fiddling with any of the things you mentioned and do you have a record of the settings when it was verified as OK?

    Lots of questions, just the sort of thing we would ask first at work where we have a lot of automated welding.

    Just a guess of something worth checking that you didnt list - gas flow. Many years ago working in a steering column manufacturing plant we had a difficult to solve weld appearance problem, welds had changed but parameters were the same, it turned out to be too high gas flow.

    PS. I'm not a welding expert as many on here are but have some experience. Listen to the experts first.
  6. GavJ Member

    Glasgow Scotland
    Thanks for the replies, funny enough I was looking at the gas regulator, new one to me... used to be a regulator that you screw down with a bullet in a glass tube flow meter but this bottle had a dial with I think 24 settings, it was set pretty high?
    The power plant is set at 9 out of a max 10 power setting.... and its a pretty big industrial mig machine
    The taper on the head pushes the outlet onto the pipe, not designed to leave a gap, not sure how I would get one in there.

    Come monday I will have a go at it again, we are about to start a job with 1000 welds, don't want them done manually.... need to get this working.
  7. GavJ Member

    Glasgow Scotland
    Update, with a bit of mucking about we got the profile a bit better, moved the torch out a bit further from the workpiece and added a bit more weave. Cant say Im overjoyed but the welds seem sound and we have dye pen checked the ones we have done and also pressure tested to 15 bars with no issues...... fingers crossed