Robotic welding is not new, but its iterations are multiplying and the robots are becoming more flexible in the types of jobs they can handle. Such is the case with the TruArc Weld 1000.
Forget the massive welding robots in automobile plants. Picture a smaller, very agile robot. Further, when it comes to doing its job, it’s a cobot. It learns from you and your inputs.
It learns quickly. So quickly, in fact, that it makes sense to use the TruArc Weld 1000 in very low-volume, high-mix production environment. It even makes sense in a one-off situation, according to the company.
We went Under the Hood at the working Trumpf Smart Factory just outside of Chicago to put the product through its paces and learn about the underlying technology. Our host was Pax Alvarez, Advanced Technology Engineer, Laser Welding, TruLaser Weld, at Trumpf, Inc.
Learn it, do it
We’ll cover the technology in a moment, but before we do, we must note that this product could have an effect on the greatest problem facing fabricators and welding shops—finding the right people. According to Trumpf, this product requires no experience. A few hours of a tutorial will bring someone up to speed on how to operate and program the TruArc Weld 1000.
To get a look at the what and the how of the weld, Trumpf set up a test doing a T-joint with two pieces of mild steel. The cobot’s weld is on both sides of the joint, thus we get two straight welds. The total weld length was about 10 inches on each side. The length of the weld was immaterial; it would have been just as quick to program a 36-inch weld, albeit the weld would have taken longer.
First, let’s let Alvarez walk us through programming and welding on this sample project:
As the video shows, to program the weld you need to move the tip to the start and end points. Before you start, you also need to provide some inputs on the handheld tablet about the job. You can choose the job number, which selects the appropriate parameters (wire feed speed, voltage, etc.) for the material, thickness, and joint configuration.
The next very brief video shows the results of the weld and why Trumpf is so enthusiastic about low-volume or one-off welds. Let’s see the results:
Making two points
When you program, that is, move the cobot to start and end points, the system uses the familiar Cartesian or x, y, z coordinates. Another set of points, the a, b, c points, tells the system the orientation of the tip. Was it at 45 degrees? Was it straight down? Armed with these two sets of numbers for each weld (and yes, you can set waypoints) the cobot is programmed.
Let’s get a zoomed in view of a piece of our previous video. Here you’ll see how the programming happens. To move the welding head, first our guide Alvarez must depress the yellow switch. This switch allows free movement of the apparatus. When he gets the tip to the right spot and in the correct orientation, he presses the yellow “ARC” button to program the start of the arc. Then he moves the head to the last spot on this side of the “T” and hits the yellow “ARC” button one more time, that is the finish spot, and will turn the arc off in the real world. Note that the ARC button is lit while it is supposed to be on, just another cue to the programmer.
It’s the same process on the other side of the T, but we already know how that works. Let’s take a look:
In this example, programming a two-sided T-joint weld took 34 seconds. By the time you add in the handheld tablet entry and the welding itself, the entire on-to-off time was about two minutes.
While we saw the TruArc Weld 1000 as a single station, one may also opt for a two-station operation by employing a partition. In this case, the cobot can move back and forth between stations along a linear axis. While the cobot is welding on one side of the partition, the operator can be setting up the next welds on the other side. Each side of the partition can handle parts up to 24 x 24 x 24 inches. As a single station, the cobot can weld parts measuring up to 80 x 24 x 24 inches. These are typical maximum sizes, but you can weld parts larger than these specs, depending on the weld locations and if the part fits on the table—which measures 78.8 x 39.4 inches.
Finally, you may have noticed in the videos that the welding unit is from Fronius (based in Wels, Austria). This particular model uses cold metal transfer (CMT) process. Actually, it’s a hot and cold process that Fronius says produces little to no spatter, and enables welding aluminum to steel, and welding ultralight gauge sheets (from 0.3 mm). Part distortion is not as likely because the process is cooler. The whole process is controlled by detecting a short circuit during the weld, then detaching the droplet by retracting the wire. These adjustments are made 130 times a second.