Shaving three seconds off of the morning commute might not be cause for celebration. Shaving three seconds off of a high-production welding cycle time, however, is.
And that’s what the IRC 5 Robot from ABB Robotics is able to achieve – that and uncounted hours of programming time. When put to the task of welding an automotive seat frame, the process cycle times for the six welds were reduced from nine seconds down to six seconds. Traveling at speeds up to 22 meters per second, it is the fastest robotic laser welding system available.
“The shear speed of the process is phenomenal to watch,” says Mark Oxlade, ABB Robotics’ market development manager for cutting and welding. “That speed is possible because the robot is able to move and weld at the same time. Previously, with fixed PFO (programmable focusing optics), the robot had to stop and stand still while the laser head was performing its welds.”
That capability comes from a Trumpf laser welding head with PFO. The PFO technology enables welding-on-the-fly coordination of galvo scanner mirrors and robot motion without the use of a PC. The galvo scanner truly makes the difference.
When a laser beam is delivered at a robot, there are two ways to create the weld. The first is with fixed optics where the fibers and the lenses point the laser at the workpiece. In this setup, the robot has to reposition itself to perform each weld.
“We’re talking fractions of sections, but repositioning takes time – and it adds up fast,” Oxlade says. “With PFO technology, the mirrors inside of the laser head are able to deflect the beam. Historically, the robot would fly to a position and whatever it could see in its field of vision, it could weld. But then it would have to move to the next area to take in the next field of vision. But now, it continually flies and keeps firing the laser. And it’s all due to the RLW – ABB’s robot laser ware – and integrated interface in combination with those mirrors directing the beam in a specific fashion.”
ABB’s IRB 6700 robot has the work envelope and reach necessary for the PFO process.
Teachable moments
Beyond the shear speed of the laser head, Oxlade mentions that the integrated interface delivers even more to the manufacturing floor in terms of significant time savings. The screens on the teach pendant are graphically easy to use, which removes most of the complexities behind operation. Users can monitor and analyze process signals during the welding sequence to optimize the process, and they can make easy, instant adjustments, if needed.
Ease of programming was also a major focus during its development.
“Offline programming is available from the Robot Studio,” says Jorge Isla, the global technology manager for welding and cutting at ABB, when describing the 3-D environment where programming can take place. “We have a replica of the controller in a virtual environment. We can generate 3-D layouts, have a functional robot working, and then bring in customer parts and program offline on a PC. Later, it can be downloaded into the real controller with little to no touchups.”
The Robot Studio lets users import scanner programs with ease and also allows for the management of the scanner head smart component. Essentially, the smart component emulates the behavior of the real scanner head and its interaction with the robot controller – the offline simulation.
Isla continues by reiterating the benefits that come when there is no disruption in production during the programming stage. While producing a model of parts to implement into a user’s pipeline, the robot can continue welding other parts.
“If you’ve invested a million dollars, you don’t want people modifying or playing with the robot while it should instead be in production mode,” he says. “In an offline world, you’re safe. You can test and try production models virtually as opposed to doing it with thousands of dollars hanging off of the robot. That could be a big costly mistake.”
With the Robot Studio, programming can also take place in an office setting as opposed to on the manufacturing floor. Beyond the importance of keeping the robots running, there’s value that comes from programming in a clean, air-conditioned environment. The mental focus that’s possible when working in front of a computer screen in an office – or even on an airplane – instead of in front of the robot on the noisy manufacturing floor is invaluable.
The PFO in the Trumpf laser head allows the robot to move and weld at the same time – not possible with a fixed-optics setup.
High volume, high quality
Currently, ABB sees its IRC 5 robot in high-volume, high-quality applications, like those in the automotive field. In regard to the laser welding aspect of the robot, speed, versatility and quality top the list of benefits that automotive manufacturers are looking for.
In addition to being capable of welding a variety of materials, such as thin-gauge steel, laser welding maintains the microstructure of the materials that automakers use thanks to the process’s low-heat input. Deep weld penetration, also inherent to the laser welding process, helps to simplify part designs. For the stringent safety requirements demanded by the automotive industry, quality welds are paramount.
“A weld must be as strong as possible,” says Oxlade. “Historically, you would have to MIG or spot weld automotive components, like the seat frames, but they didn’t have the same quality and integrity that laser provides. In a crash test, seats would fail if the welds weren’t as good as they could be. The laser weld gives manufacturers the confidence they need in the operation.”
According to Tracey Ryba, one of the laser product managers at Trumpf that developed the laser head, the system can handle a wide range of power inputs up to an 8-kW fiber-delivered laser. He describes the current setup as being the second-generation delivered by Trumpf, the PFO 3D (PFO 3D-2). In the future, it will also be available with the PFO 33-2, a 2-D scanner.
The PFO galvo scanner can be powered by any Trumpf TruDisk – one of the most flexible power sources on the market today – and can be between 1 kW and 8 kW. Ryba mentions that, most often, the robot is powered by a 6-kW laser.
In accordance with the growing needs of today’s manufacturers, Trumpf reports that the work area of the new generation PFO 3D-2 is bigger than ever. Its maximum size tops out at 695 mm by 1,080 mm in elliptical form with a Z stroke of up to ± 475 mm.
The IRC 5 robot can also be mounted with similar-style heads from other third-party manufacturers and laser power suppliers, such as IPG Photonics. When it was debuted at Automate 2015 at Chicago’s McCormick Place convention center, it was outfitted with the Trumpf laser head.
So although the robotic solution won’t be shaving off any time from the morning commute, it’s reducing overall times on the manufacturing floor. And as far as that commute is concerned, by increasing the quality of the automotive welds, the robot is, in turn, also increasing driver and passenger safety.
