Have you looked at a robotic cell?

Over 20 years ago when robotics were first being implamented at Dana/Parrish for the production of auto frames, We had problems of (2) different natures.

1) The stamped components varried a fair ammount giving inconsistant fit up.

2) The production operators were of the mind that PEOPLE should be doing the work, and that if this ever caught on, the plant would be full of robots, and the former employees would be SOL.

In order to deal with problen 1, the fixturing was set up to give as tight a joint on (1) side of the part, and THAT side was welded roboticly. The other side was welded by a line welder [person] who could deal with the inconsistant joint gap.

Problem 2 was never completely resolved, but the operators did, to a degree accept the inevitable.

These welding lines produced the same parts all the time for years on end with only minor incramental changes. The robots were Hobart Moto Man units from the late '80s, I would expect modern equipment to have improved substantially.

Consider Joe Kane's points [all of them] but particularly that about lot size and frequency of production. If You run the same jobs repeatedly but in small orders You may stand a chance, but if every job is different and runs are short You have a rough road ahead of You.

Joe had some excellent points about robotics. Another one would be that if your going robotic you go total robotic or you will be maintaining two entirely different systems. Your tolerances have to be much tighter, material lead times will be increased, and if you have a great diversity of parts forget it. If your working to ASTM parts forget it.

You have to get a lot of cycles for the efficiency of robotics to pay for the initial investment plus upkeep.  Just price an actuator motor on a Fanuc five axis...or for that matter just limit switches and sensors, the switches die fast.  If you are doing runs of 100 pieces and doing the same five or six setups on 100 pieces at a time it might work out fine.....I would not consider robotics unless I was going to make in the 10's of thousands of the same piece a year.   Or unless it was a very long cycle time part...you got to think in man hours per piece to make this work out.  Caterpillar has this split of priorities down pat.  Typically a robotic setup reaps rewards faster on long cycle time parts, on small quick things you must be producing vast quantities to make the robot economical. Think 24/7 kind of production.  I setup and robotic run laser welders with robotic parts loaders and it was a sickeningly efficient way to make a high precision part with an amazing degree of weld quality and repeatability.  But robotics lend themselves to dedicated production lines not short runs of custom one off parts.....if you know your building the same more or less parts for the next five years then definitely look at the tooling investment.  I am not a production efficiency expert, just a guy who has been there and done that.

I would say my job is about 20-30% robotics.  It's hard to give a good sense of ROI etc as there's so many factors. Process, fit-up variance tool path complexity etc. 

I would say robots generally have a much higher arc efficiency than manual welders. My old rule of thumb was that a properly designed cell would run work about 3x as fast. Again there's lots of variables.  We ran batch work but never did something that was high mix  low volume.  You would have to account for tooling time changes.  IF you're truly doing custom or one-off batches then you would have to factor in programming and would pretty much need a dedicated programmer/tech to off-line program all the batches.  Unless the work is repeatable the ROI might not be there.

Conversely a properly designed cell can lead to lower defect rates (process dependent). A robot can save down stream costs if you're not repair 1-10% of welds. Also it sounds like you have a big part mix, it might be more wise to have a Robot hits 90% of the joints or the easy joints and manual welders get the tricky stuff. Conversely it might sense to get in a small work cell that can handle the handwork so your company can build up the internal lessons learned before dropping the big dollars for a huge cell. I had good luck cutting down defects and upping productivity with robotics, but quality was our concern more than cost as rework was difficult/impossible so scrapping was very uneconomical.

I would talk to the big integrators. If you're serious they will usually come look at your product and proof out a cell with a quote. With that they should be able to demo cycle times and put some actual numbers on it. Of course they are there to sell robots but the well known guys aren't going to over-promise you or give you useless features unless someone in management wants all the bells and whistles...

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