>I`m making a study about seam tracking
>I need a seam tracker for 30mm-200mm welds that doesn`t interferate with the cycle time and doesn't restrain the torch mobility
>SOOOO, Laser and Tactile sensors ------> OUT
>After some reaserch i concluded that WELDGUIDE (or any tru-arc seam tracker) is the best
>I mean, there wold be no reason to use something else ....
>I know is not like that, to finish the study i need some negative things about the ABB Weldguide
>Also, i need help with some aplications or compannies that already use WELDGUIDE (or some testemonials)
I wold be so happy if somoene could help me
Not to be rude but I think your conclusions are prematurely made based on a theoretical exercise.
Any method will affect the cycle time and/or restrict torch mobility, after all, seam tracking is only compensating for variations in the parts / production - so the "best" seam tracker is the one you don't have to use in the first place.
If you need weldguide / seam tracking, then you will need tactile sensing (or a 1D laser / seam finder), because the corrections are not instant, it will take a while for the robot to find it's "home" / the joint while tracking plus it's much more difficult to start off bad and finding the seam v.s. starting in the right spot and staying there.
The "best" seamtracker is part, material, joint configuration, process and customer dependent so it's very difficult (not to say impossible) to make a blanket recommendation.
One negative thing I can say about any seam tracker is that they were sold (and perceived) as the end all be all solution to any problem. Just slap a tracker on there and you won't even have to program, just toss the part on the floor and the robot will weld it all up by itself....
With all that said....
If this is a live project where you're trying to figure out what's best for you, then let us know all the parameters and we can go from there.
If it's a study / project for school, then we can look at it from a more theoretical point of view - just let us know.
Is kind of both,
I almost graduated and i`m making the study at a big company.
We have issues with some workpieces that are not being welded propertly because of small differences in the geometry and the fact that same piece comes from multiple identical welding cells (that have different tolerances).
As you said in theory, WELDGUIDE seams (he he) like the Holly Grail but i wonder why i can`t find proper documentation on this.
I don`t expect someone to solve my problem, i`m just asking for guidance and where to find more unbiased info about this.
As i said we are a big company and we have contacts with ABB, but in our country there is only one company that uses this method.And the testimonials are only from ABB and they say it works wonders.
About the issues; i know it is restricting the torch mobility, we have errors under 0.5 mm, so it will be an almost unnoticeable weave so the torch won`t hit anything in this setup.
And for the distance to "home" how can i calculate, or approximate it ? from some videos i saw that in a V pattern (the configuration we need) i saw that [Home position = 3 x Initial displacement] so, by having a initial displacement of 0.5mm the robot will find home in 1.5 mm , which is not a problem on a 45mm weld
We are making 800+ heavy pieces per day and the process is optimized, the issue is that we have to retouch almost 200 pieces a day because of a small variation.
Edit: About the cycle time , if we increase weaving speed so in a manner that don't affect advance speed the cycle time will increase?
(except the minor triangulation in the beginning)
I mean, the welding speed will modify after adding the system?
When you say heavy pieces, what's the material (type, thickness, etc.) and what is your joint configurations (only V-groove ?)
What kind of welding wire / gas do you use ? How many layers do you weld ?
Is your part/joint variation only 0.5mm (that is exceptional for larger / heavier parts) ?
What is the welding problems that you need to re-touch / re-work ? if it's only an 0.5mm error then my guess is that you have issues with penetration in the root layer ?
Do you use any sensors at all today ?
We are currently using mechanical sensors that detects the overall geometry of the workpiece, but this method doesn't handle the multiple welding correction.
Mostly v groove but we have some lap joints too. The thickness is never less than 2mm.
When I say 0.5 I say the distance between the center of groove and the center of weld.
To be honnest 0.5 mm seems to me a low value, but this is the information I have from the plant.
I can go there and research more to be sure that they are not talking about 0.5 cm.
But even with that, what are the issues implementing weldguide on this type of application?
We have weldguide and smart-tac on our system. I use the smart-tac to locate the start point and seam track the weld. Works awesome. The seam track needs 10 weave cycles before it starts to track. My company produces industrial snow removal equipment so our robot welds everything from dump body tailgates to side wings. Overall it works well but shit wire with bad cast can be an issue. Multi pass option is good for finding v- grooves too. I use the weldguide on everything so if you have any questions I’m usually on here at least once a day.
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Does anyone know how to approximate the distance until the robot starts to track?
We have some short welds , 30-50 mm , my question is how much the torch has to travel until the weld is applied where it needs to be.
10 cycles like Jarm mentions is a good rule of thumb, but that doesn't mean you can do a 10hz 0.2mm wrist weave and expect it to be spot on after a second (which even at moderate weld speeds would equate to a 10-15mm distance).
Your welding parameters will influence tracking a lot, as we discussed offline, are you pulsing and/or using a powerful spray arc ?
You can change welding parameters / speeds to make it react faster (and/or in a shorter distance) but then you're sacrificing cycle time, so in the end you'll have to pick your poison - quality / less rework or speed.
What welding speeds do you have (on average) ?
We are using a powerfull spray arc and the speed is 72 cm/min