A "Bricklayers" guide to Robotic welding

[Robotstar5]

A welding robot, most robot manufacturers produce something similar. 6 axis powered by 6 servo controlled electric motors capable of carrying 5-10 Kg at about 2500mm per second with an accuracy of 0.1mm.




Welding power source can deliver 5 - 480 amps.




Wire feed unit mounted on top of robot supplied with wire from a 475Kg bulk pack and plumbed in gas.




Weld controller, the "brain" stores the weld parameters for each individual weld. When the robot is ready to start a weld the controller switches on the power source and wire feed unit then monitors the weld characteristics.




Close up of weld controller screen.




Weld controllers are networked to a central PC to allow process monitoring and changes to be made.




Components are loaded into a fixture then indexed 180° to face the robots.




Component is welded by 2 robots to reduce cycle time.




Fixture position is controlled by master robot to give best access to welds.






Fixture can be rotated upto 360°.




Every 3rd cycle the robots go to a torch cleaning station to have spatter removed by a reamer and a squirt of anti-spatter, there is also an air blast through the torch to remove any bits.

Each welding cell is controlled by a PLC (industrial computer) any weld failures are detected and flagged up to the operator.
Some of our cells have nearly 100 welds per cycle!

Thanks to Keiper UK for allowing me to photograph equipment.

 

[wyn]

Interesting stuf.
Do you have to manually go through the welding movements to programme the computer ?

 

[Hitch]

Nice, its good to see stuff like that.

How are the parts held in the jig? Lot of cables on it, electro magnets. and looks like a few toggle clamps?

 

[Robotstar5]

Do you have to manually go through the welding movements to programme the computer ?

Initially takes a few hours moving the robot to points to be recorded using a box of buttons called a teach pendant.
Day to day running sometimes need to modify the odd weld position to accomodate piece part variations.

 

[Robotstar5]

How are the parts held in the jig? Lot of cables on it, electro magnets. and looks like a few toggle clamps?

Parts are mainly held by manual clamps that are locked by air and a few automatic ones that come on when the operator presses the "go" button.

A lot of the wiring is for part detection (poke yoke) to make sure no parts are left off (idiot proofing), the machine will not cycle with parts missing and tells the operator what he's left off via screen next to the load position.

 

[Sparkey]

Very good Stu! and well explained!
Very similar to our robot set-ups!

 

[Robotstar5]

Very similar to our robot set-ups!

Do you have any dopey operators as well?

 

[Sparkey]

Do you have any dopey operators as well?

ANY???
welding the jigs, forget parts, let the robot out of the protection cage......pfff and i can go on... once i even seen one change the jig and let it bounce on the floor...only, the jig didn't bounce...

 

[Endacy]

That's interesting stuff! Thanks for showing us.

What sort of things are made in these types of machines? When I see welded bits of ordinary things like chair / table legs, shelf brackets and what-not I always wonder if it's manually done or not?

 

[Robotstar5]

What sort of things are made in these types of machines? When I see welded bits of ordinary things like chair / table legs, shelf brackets and what-not I always wonder if it's manually done or not?

Over the years I've done aluminium table frames, stainless sinks, lots of mild steel parts for car industry, alternator housings for trains & gensets, kwikstage scaffolding amongst others.

 

[Sparkey]

Yes and besides the mig set-ups we also have a robot which is welding with electrodes (maybe stu should explain this... i don't know the right words)...thatone is for the pedalboxes (the actual box)

 

[Robotstar5]

Yes and besides the mig set-ups we also have a robot which is welding with electrodes

Usually called spot welding, proper term is resistance welding.

Spot welding robots normally capable of carrying 100-150Kg loads at a couple of metres per second

 

[cookie munsta]

Nice, its good to see stuff like that.

How are the parts held in the jig? Lot of cables on it, electro magnets. and looks like a few toggle clamps?

That is interesting sure but how many jobs did that cost?
Not having a go, but the management who put these into use just need one that programs itself, and then they will have a great bottom line........and no one to share the moment with
some of these are nessecary to keep up with demand but they will bring out cnc welders for everything soon. like cnc lathes, brake presses etc.
oh thats where my beer was, any way, sorry where was I?

 

[Sparkey]

Haha! well lucky for us these robots can't load themself...so there's always someone who puts the parts in place that have to be welded! (and takes them back out again offcourse)
And like Stuart knows (but doesn't want to admit) the robots make mistakes too! And this is where the "tackers" come in, welders who tidy up the welds that are gone wrong or missed by the robot....
So we really shoulden't worry about it, yet! There's still a lot of work and improvements to be done on robotic welding!

Beer? at this time of the day??? (oh right...you're in Australia...what time is it over there now?)

 

[cookie munsta]

Haha! well lucky for us these robots can't load themself...so there's always someone who puts the parts in place that have to be welded! (and takes them back out again offcourse)
And like Stuart knows (but doesn't want to admit) the robots make mistakes too! And this is where the "tackers" come in, welders who tidy up the welds that are gone wrong or missed by the robot....
So we really shoulden't worry about it, yet! There's still a lot of work and improvements to be done on robotic welding!

Beer? at this time of the day??? (oh right...you're in Australia...what time is it over there now?)

Beer o'clock, I think, my clock is ****ed

 

[cookie munsta]

seriously. half eight on friday night

 

[Robotstar5]

That is interesting sure but how many jobs did that cost?
Not having a go, but the management who put these into use just need one that programs itself, and then they will have a great bottom line........and no one to share the moment with

I can see your point, this machine has 35 seperate components (others have twice as many) to be welded, if we could find an operator who did not forget to load all the parts (and they do forget!) for an 8 hour shift then weld them consistantly we would not need the machines. I suspect the build rate would be at least halved using manual processes = higher unit costs = less business!

We have 2 main customers, one of which requires machine welded parts as part of contract as it guarantees (mostly) consistant weld quality.

A good example of the costs is when we inherited a new machine using 0.8mm wire, we wanted to swap to 1.0mm to bring in line with rest of plant but components would need to be re-tested including vehicle crash testing before approval = many thousands of pounds!

 

[arceyered]

I worked on a walking beam Robotic Line welding 4x4 chassis.
"The job used to be done manually"
When they changed over to Robotics the quality went through the floor they were rubbish the robots just cut the chassis to bits.
problem being they could not produce consistent components for the frames

We did not have a problem on the carousel doing them manually the mk! human eye ball adjusted and welded accordingly.

It cost more to produce the frame with robots and a lower quality

 

[Luke]

Great pics

The man/machine argument can go on and on. The end result, like it or lump it, is pretty much always the same.

But hey, it keeps me in a job, so can't complain....

 

[Robotstar5]

problem being they could not produce consistent components for the frames

That's the problem, Robots are inherrantly stupid, they will weld the same place to 0.1mm every time, if the component is not where it should be it's the design / engineering, not the robots at fault.