# Rotational speed of fanuc positioner for welding

• Hello all,

I'm trying to get an idea of the best way to program a positioner to rotate in a welding application. My positioner is mounted in front of the robot, spinning around the X+ Axis. A tube and fitting will be spun for a full circle weld. Robot will stay in the same world position/orientation while the tube spins. So far, I've programmed the positioner to spin at L P[1] 35in/min FINE. This did not work though. It seems to be way too slow and my weld bead turned into a weld puddle. Just for note, Robot and positioner are their own groups.

Edit: Simplified post

• I don't know how your positioner is set up but using inches per minute may not be the way to go.

When you spin something in A circle the closer to the center you are, the faster it spins.

Both near the center and farthest edge of A disk both travel 360 degrees when rotated one complete

cycle. The farthest away travels much farther than the center. Try changing point to J 100 % fine for the positioner. Then adjust your travel with the % value. Surely some trial and error will occur, don't be afraid to make drastic changes in the % value when you start, will get the results you need faster.

• I don't know how your positioner is set up but using inches per minute may not be the way to go.

When you spin something in A circle the closer to the center you are, the faster it spins.

Both near the center and farthest edge of A disk both travel 360 degrees when rotated one complete

cycle. The farthest away travels much farther than the center. Try changing point to J 100 % fine for the positioner. Then adjust your travel with the % value. Surely some trial and error will occur, don't be afraid to make drastic changes in the % value when you start, will get the results you need faster.

Positioner needs to spin at in/min per customer requirement's for weld speed unit type. I figure that's why Coordinated Motion may need to be used...because that would then tell the positioner how fast to spin compared to Robot TCP. It's just a slightly messy way of taking care of my welding situation since the same weld job is used in different positions along a 2000m rail...So I'd either have to write a weld job per each position (200+ of the same program) or write 1 job with an indirect PR...but that's where the Coordinated Motion gets messy and why I am hoping to avoid Coordinated Motion, but it's looking like my ONLY option right now.

EDIT: Oh and I can't use Joint % because that is not in IPM for the customer's quality database.

You could specify the speed in degrees per second and figure out the IPM based off of the circumference of you work piece.

• You could specify the speed in degrees per second and figure out the IPM based off of the circumference of you work piece.

Yeah, that could definitely work. Sometimes the answer is much simpler and I miss it.

I'll go that route, thanks.

• I need to know how to set my robots to do the same thing. New at this. How do I make this program?

• All you have to do is...setup Coordinated Motion between the Robot and the Positioner.

As for the program...The weld program will have your Robot Group and the Positioner Group masked to it. I used 2 Circular Motion Types (4 points total) with the Robot's Position being the SAME. The Positioner's Group rotates a quarter of the way through each Circular Point.

• Hey guys, I am having the exact same problem. I have to make a few of these circular welds with a rotary table and calculating the speed by hand for each one gets tedious very quickly. I am guessing there is a way with the COORD function to adjust the speed with a welding schedule? But anything I try with COORD just moves the welding torch with the table.

If i remove the COORD parameter from the point the table just turns at about 100deg/min (I can change the speed by changing the weld schedule).

Anyway to do this more elegant?

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• .. But anything I try with COORD just moves the welding torch with the table...

You cannot just delete the coord option in the movement, you also have to change the corresponding position.

If you want to do a circular path you also have to use a C movement, not a L. As a L movement in coordinated way with rotating the table will end in a linear path on the table, not a circle.

A circular movement with coord function is done by rotating the table for a some degrees (less than 180 degrees) and then touch up that point, and so on. And use C movements.

• I did try it that way. 2 C points to make a full circle, but the welding speed was not that of the welding schedule.

After some testing I found out it works as long as the positioner is not tilted (Its a 2 axis manipulator, I plan on rotating the part on its side 90deg, and using the other axis to rotate the part). As soon as I tilt it 90deg, the speed doesnt match. If it's in its default position (0deg - turned straight up the Z world axis) the speed matches with the weld schedule. Different radius and all works fine in the default position.

Im guessing the TCP of the manipulator is not set properly?

• Ye, sorry about that. I should've posted some more info about the machine. It's a Fanuc ARC Mate 100ib with a R-30iB Plus controller and a small Fanuc made 2-axis table.

I've only been playing with it for a few weeks and I haven't set up any user frames. It's by default the same position/rotation as the world frame I believe?

• I've solved it by using the unknown pt calibration method for setting the COORD pair and calibrated both axis of the table.

Works perfectly now. Strange thing tho since the integrators manual (not an official fanuc one) says that fanuc made tables should allready be calibrated...

• The coord pairs calibration depends on the relative position of the table from the robot.

So Fanuc can't possibly calibrate it
Strange manual indeed

• I might be missusing the terminology here. There's two different ways described to calibrate coordinated pairs:

- method with a known configuration. Used for a Fanuc robot and a Fanuc table. Just set the table tcp, origin and x/y directions of the leader. This one was off if I tilted the table on its side.

- method with an unknown configuration. This worked nicely.

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