In this article, Steven Lucas of LVD highlights the key factors that have changed bending automation.
The landscape has changed for robotic press brake bending. Advances in machine, software and robot technology have made bending automation more practical for a broader range of fabricators across Asia Pacific as they look for ways to optimize workflow, shorten turnaround time and lower their per-piece cost.
Just a decade ago, bending automation meant a significant investment—in the cost of the automation and in the support required to realize an efficient and consistent bending process. Six key factors have changed bending automation:
Today’s programming software for robotic bending is more powerful and much easier to use than the software of 10 years ago. This has resulted in simplified CAM program preparation, creating robot trajectories, machine setup and operation. Programming a robotic press brake can be handled completely offline with no need to physically teach the machine setup or bending of the first part. In contrast, in some automated press brake operations, robot teaching required approximately one hour per bend. This eliminates considerable downtime and ensures that the throughput of the bending cell is not interrupted. The software automatically generates the robot’s movement, directing it from one bend to the next to form the part and then to offload or stack the part. The software is able to calculate a complete collision-free path – generating the robot’s trajectory through all positions.
More than programming the robot, software with CAM 3D virtual production simulation capability provides a complete walk through of the robot and press brake functions so the user can check and visually confirm the bending sequence before bending begins. Before a piece of metal is formed, the process is verified, avoiding costly mistakes and material waste.
Flexible Robot Gripper
The robot gripper is a critical component of a robotic system. Gripper designs of the past did not have the flexibility to accommodate the many part geometries of bending. That meant investing in a number of different grippers to handle different part geometries and taking the time for gripper changeover, which could involve multiple changeovers per part. New gripper designs are much more adaptable. The gripper in Figure 1 is a patent-pending universal design that fits part sizes from 30×100 mm up to 350×500 mm and handles a maximum part weight of 3 kg. This adaptive design enables the user to process a series of different geometries without having to change the gripper. It’s possible to make bends on three different sides of a part without regripping. Use of a universal gripper not only saves on investment cost but also saves costly change over times between grippers, keeping production continuous and uninterrupted.
Capable Industrial Robot
The use of industrial robots worldwide is on the rise. The International Federation of Robotics estimates the supply of robots to be 521,000 units in 2020, more than doubled in just five years. While the automotive and electronics industries are the leading users of robots, the metals industry is a growing application.
Robots themselves have also improved in terms of capacity and reliability. One of the world’s leading robot manufacturers offers more than 100 industrial robots with a payload from 3 kg up to 2.3 tons and maximum reaches up to 4.7 m.
Fast “Art to Part”
Another advance in robotic bending is a faster design to part process. The press brake bending cell in Figure 3 takes 10 min for CAM generation of the bending and robot program, and 10 min for set-up and first part generation—a total of 20 min from “art” to “part.” That’s a result of the tight integration between the press brake and robot, and easy to use, intuitive software.
Better Process Control
Real-time in-process angle measurement technology adds advanced process consistency to robotic press brake bending. An angle monitoring system can adapt the punch position to ensure precise, consistent bending. In the system pictured,
digital information is transmitted in real time to the CNC control unit, which
processes it and immediately adjusts the position of the punch to achieve the
correct angle. The bending process is not interrupted and no production time is lost. This technology allows the machine to adapt to material variations, including sheet thickness, strain hardening and grain direction, automatically compensating for any changes.
In the past, fabricators have tended to “over automate.” Despite advances in function and flexibility, a robotic bending cell still represents a sizable investment. In order to generate a healthy ROI, it’s important to ensure that the ratio of the cost of the automation is not more than twice the cost of the stand-alone machine. Getting this ratio right keeps the direct cost of the part at a sensible level—the direct part cost is not “loaded”—and the user does not need large volumes to make the process cost-effective.
Also, worth considering is the versatility of the system. A bending cell that has the flexibility to operate in stand-alone mode when batch sizes are too small to benefit from robot automation will be more productive and profitable and, therefore, easier to justify. In this scenario, the user can operate the robotic bending cell lights-out overnight or after-hours and during normal business hours, can choose to work in either mode (with the robot or with the robot parked). In the bending cell shown (Figures 5 and 6), programming is handled with 3D bending software so that the same program can be used for bending with the robot or for manual bending.
Is Bending Automation Right for You?
What jobs are best for a robot? Surprisingly, it’s a fairly broad range of applications, including high-volume repeat jobs, low-volume jobs that are reoccurring, and jobs that are heavy duty. The flexibility of today’s bending automation technology makes it possible to run a variety of bending jobs profitably.
New bending automation products, such as LVD’s Dyna-Cell, eliminate the need to teach the robot, which greatly simplifies robotic bending. Current bending cell designs are also much more affordable than past models, both in the cost of the press brake and robot and the cost of operation and maintenance of the cell.
In the Asia Pacific region, as manufacturers are encouraged to adopt automation and Industry 4.0 initiatives through government loans and grants, bending automation offers fabricators a way to address issues such as shortage of labour, higher cost of wages and quality control. If you think bending automation may be your solution, it’s best to consult with your equipment supplier.
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