FabTech 2008 Robotic Welding

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[ame]http://www.youtube.com/watch?v=YMzRikFwCBU[/ame]http://www.PlasmaMetalCutter.comGiantTech Cut40DGiantTech Cut50DGiantTech CT520DGiantTech Tig200sGiantTech Arc200GiantTech Tig200PACDCMiller MM210No Brand Chinese Chop SawNo Brand Chinese 4" Angle Grinder
Reply:It's neat, but in most applications, it's only wasted money.  A robotic welder can't compensate for changes in fitup characteristics.  For example, if there's a fillet weld with a little gap, the robot will continue its path without slowing a little to add more metal to fill it.  A human can compensate and adjust to many more changes.In other words, you often will have to spend so much more time getting consistent fitups for a robotic weld that it's just not worth the cost of buying it.
Reply:Thanks Giant Tech. Pretty neat video. I wonder- if the robotic tig welder dunks its' tungsten, does it cuss like we do???!!!!And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Originally Posted by EngloidIn other words, you often will have to spend so much more time getting consistent fitups for a robotic weld that it's just not worth the cost of buying it.
Reply:Originally Posted by ss42768Robots are absolutely worth the cost, as long as good parts are fed to it. I would not waste my time programming a robot to whip, weave or whatever just to compensate for bad parts fitup, nor would I expect a manual welder to do the same. I have been involved in several robot sales, and one point that is spelled out in the quote is parts tolerance requirements, usually when I ask a customer what his tolerances are, they'll say something like, "we can hold an 1/8 or so" I tell them that when they can hold 1/2 or less the diameter of the weld wire, then we'll talk. The time spent to get good parts is definitely worth it, and doesn't matter if it's a robot or manual welder. Many times a year I get calls from customers asking for help in cutting their welding costs, most of the time these customers are overwelding, when there print calls for a 1/4" filet weld, they put down a 3/8" filet, or when an operator feels he doesn't have enough shielding gas, he cranks the flowmeter way up, I could go on and on, but the bottom line is time is money, if you've ever sat in a welding booth for 8 hours a day with a stopwatch, clicking it on and off only when the sparks are flying, you will see what I mean. If the majority of that welder's time is spent fitting parts, cleaning spatter, overwelding, not following weld procedure's etc; he is costing his employer big money.
Reply:Another and more to come.[ame]http://www.youtube.com/watch?v=ZcAIESNUtZg[/ame]http://www.PlasmaMetalCutter.comGiantTech Cut40DGiantTech Cut50DGiantTech CT520DGiantTech Tig200sGiantTech Arc200GiantTech Tig200PACDCMiller MM210No Brand Chinese Chop SawNo Brand Chinese 4" Angle Grinder
Reply:Engloid, you are correct that robots aren't worth it for most applications.  The places they are worth it are long repetitive production jobs, doing the same (or similar) parts for months on end.  Fitup, fixturing, programming, and overall part design all contribute to how well the robot will be able to weld the part.  I work in a job shop that has a pair of robotic welders.  One of them currently runs for something like 30 hours per week (all that's needed to meet customer demand for the six parts run through the robot).  One operator and the robot can do the same amount of work in one day that took two welders two days before.  We've been build this series of parts for this customer for over six years, the last three of which have been done using the robot.  The other robot currently sits idle as we haven't had any work come through in recent months that was suited to the robot,  specifically the investment in designing and building fixturing and the programming of the system.  Takes a lot of parts to recoup those costs.  The last job we ran on this robot, it averaged just over 8lbs/hour deposition, waste wire per 661lb drum was under 10' (4' of torch plus various wire clippings for torch calibration).  More fitup time isn't necessary when running through parts on a robot.  There are plenty of plate processing systems out there that can produce parts more than accurate enough to make this a non-issue.  And if you're stuck with cuts that are cuts using a lesser quality plasma system leaving a poor kerf on the part, just make sure that the parts are all nested on the plate so that the kerf has the same orientation on each one, then you have repeatable poor fitup, which can be compensated for (slow the weld speed a hair on the side with the gap).  I'm not talking about sheet metal parts here, but 3/8" to 3/4" plate, as that is what my robotic experience consists of.  The only reason that I can see for having random fitup gaps is using structural shapes, which I see as a part design issue.  Only option there when there are 3000 of them and you're told to program the robot for them, is to set the weld parameters so that weld size is met in a worst case scenario, and let all the rest be slightly oversized (had to do that before).  Although I've never used it, I know ABB does have an adaptive fill setting that's designed for multi-pass v-groove welds.  Supposedly it detects when the groove is filled and adjusts weld parameters.  Don't know how that works though.  The kind of welding the robots do is exactly the kind of welding I don't want to be doing.  Showing up at work and welding the same parts day in, and day out for months on end.  To me that kind of work is extremely monotonous .  Currently I do mostly different parts each day, keeps the work both interesting and challenging, the kind of parts ill suited to robotic work.  ss42768, sounds like you know a thing or two about robotic welding systems.  For the benefit of those that don't know much about them, the reason weaving is so common with modern robotic welders is for seam tracking, not to bridge gaps.  The robot controller samples the welding amperage near each extreme of the weave and uses this data to adjust the weld path, and tip to work distance.  If the amperage is greater to the left of the weld than to the right of the weld, then the weld path needs to be adjusted towards the right.  This is because amperage goes up as the tip-work distance decreases, if amperage is different left to right, then the tip is closer to the work on one side indicating it is outside the joint towards that side (if it's perfectly in joint, the tip-work distance at each extreme of the weave will be the same, therefore the amperage at each side will be the same).  To correct this, the controller can offset the weld path to get the weld back in joint.  Average amperage during the weld is compared to a target amperage set during programing to keep a constant distance from the weld joint (keeps the robot from getting too close or too far from the puddle).
Reply:Robot welders have replaced skilled welders in the majority of production welding jobs.been to an auto plant lately? the best use i have seen lately is a shop that builds up shafts for different applications, they have a lathe/robot cell.   it takes a rather boring tedious job to free the welders up for the other non monotonous work.nothing worse than seeing a talented welder strapped to a repetitious piec of work.insert thoughtful quote from someone else2000 Thermal Arc 300GTSW 3.5 hours1946 Monarch 20 x 54 Lathe1998 Supermax 10x54 Mill2004 Haco Atlantic 1/2" Capacity Lasernot mine but i get to play with it
Reply:Originally Posted by EngloidThere are way too many generalizations in this post.  FACT is that in most welding applications, a robot simply isn't worth the money.  You can argue all you want to, but if they were so feasable, we'd have a lot more of them out there in operation...and a lot less demand for skilled welders.
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Reply:How's this for a band saw? Attached Imageshttp://www.PlasmaMetalCutter.comGiantTech Cut40DGiantTech Cut50DGiantTech CT520DGiantTech Tig200sGiantTech Arc200GiantTech Tig200PACDCMiller MM210No Brand Chinese Chop SawNo Brand Chinese 4" Angle Grinder
Reply:Originally Posted by chenryRobot welders have replaced skilled welders in the majority of production welding jobs.been to an auto plant lately?
Reply:Well, just my .02 from a robot owner,Robots definitely have their place in welding.  For most application, people use GMAW robots, which are infinitely more forgiving of fitup issues than GTAW robots.I have a cold wire feed GTAW robot, 6 axes on the robot, and another two on the manipulator.  Yes, in single piece one-off's, it may not be cost effective to program the robot.  And yes, there is a limit to how much fit-up problems it can deal with.  However, on most of the production welding that we do, the robot is more capable than the humans.  Given arc-length control, the robot can hold more consistent arc length over the distance of the weld.  Given sensing technology, the robot can tell when the parts aren't in the right place, or if the joint has wandered.  Given vision, the robots can actually see the joint.  Robots don't get hungry, thirsty, have to go to the bathroom, or care that the part has risen to 300 degrees F and need to take 1/2 hour off to let it cool down.  I have parts that require a 20 foot contiguous weld, without breaking the arc.  A human can't do it.  I have parts that my human welders need 3-4 hours to weld.  Using 8 axes, the robot performs the same operation in 20 minutes.  30 inches per minute is a pretty impressive travel speed, considering the manual welders go at 2 to 3 inches per minute.That being said, I have one robot, and 10 humans.  The robot has it's place, so do the guys and gals.  Not one of my welders lost their job when I put in the robot, rather, they now get to learn programming and develop better skills in weld schedule development.  Gotta remember, while the robot can accurately repeat the weld over and over again, it doesn't know it need 1/16" standoff with 130 amps at 30 ipm with 45 ipm wire feed, or how much cover gas to use.  It can't change out it's tungsten, well, not yet, one of my guys is working on a program so that it can.  Welders still have to program the process variables. Best regards, KbnitI r 2 a perfessional
Reply:When I was racing motorcycles, i got to go to see a factory and the operation that put the very same frames I raced together. Pretty cool, a mix of people setting the main parts in, the machines setting the engine mounts, setting the steering head, the swingarm pivot up. It got jugged, all that was by robot. Then, it went berzerk welding the frame up. They would then check the frames for tolerances, and the very best ones- we got some of them sent to Gardena tot he race shop. It was interesting, because we looked for certain stem angle and swingarm pivot locations. The frames were all the same, but there are definitely a couple thousandths here and there in variation, and the tuners knew what they wanted most. The robot welded a frame in about the same time it would take me to do maybe 1/6 of the job. Wicked fast and accurate.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.