Cell Evolution

The robotic bending cell evolves to offer more flexibility

YOU CAN ALSO LISTEN TO THIS ARTICLE

As robots continue to be integrated into the workplace – in manufacturing as well as other industries such as restaurants and retail – business owners and workers are more accepting of automation, realizing the gains of efficiency and productivity as well as an improved work environment.

LVD’s new generation of robotic bending cell features an 80-ton press brake with crowning system and built-in adaptive bending technology coupled with a high-payload robot and multiple gripper options to support a wider range of bending applications. 

With increased adoption has come the need for more flexible automation solutions to suit a broader range of users. Case in point: The evolution of the robotic bending cell. Fab shops seeking to automate their bending process – one of the most labor-intensive operations in metalworking – are discovering that the latest generation of the robotic bending cell is more flexible than ever before.

From fixed to flexible

While an OEM with steady-state production runs might easily justify automation equipment, a job shop requires a high level of flexibility in their production machinery to satisfy a variable mix of jobs in both current and future work.

Early robotic bending cells had a narrow, fixed range of use – light payload, limited reach and limited workpiece size. For fab shops, this meant the bending cell often failed to meet the challenge of changing orders. As the bending cell has evolved, it’s become more capable and customizable.

Figure 1. This tabbed part was engineered specifically for robotic bending.

Advances in industrial robots are a part of the story. The modern industrial robot is compact in size but robustly built for the environment. It can support a higher payload capacity (rated at 150 kg) to bear greater loads. A longer robot reach allows it to efficiently cover a large work area. Because it’s balanced to maximize the load capacity and the range of reach of the robotic arm, the result is a more flexible bending cell able to achieve optimal cycle times and offer a larger output area.

The robot’s payload also influences the weight capacity of the robot gripper and part and the applications and workpieces the robot can handle. A robot with a heavier payload can support a larger surface area and part sizes as well as various grippers for different part formats. The robot gripper is often the cell’s most restricting feature. A cell capable of accommodating multiple gripper sizes allows the user to handle a changing landscape of work, from small brackets to large parts and complex forms. Different grippers give the cell flexibility to work with corrugated metals, parts with lots of holes, a non-flat surface or material that is magnetic.

The LVD Easy-Cell features a standard combination gripper using cups and clamps for small parts. There are several grippers available for medium-sized parts (500 mm by 500 mm square) and a gripper for larger parts (1,100 mm by 650 mm rectangle), effectively addressing a range of applications. For perforated sheets or parts with a lot of holes, a magnetic gripper is offered. This makes the cell very flexible for a wide range of parts.

LVD’s Easy-Cell accommodates a variety of grippers to handle a range of bending applications

Certain suppliers (including LVD) also develop custom grippers to specifically suit end user applications.

Easier programming

Software is another big key to cell flexibility. Lack of skilled labor is a leading reason to automate. Shops are automating not only to fill the gap of experienced operators, but also to add a second shift or lessen the workload of existing employees.

For many shops, the robotic bending cell offered the lure of automated operation, but, in reality, required experienced robotics personnel to setup and operate. Advances in robot software applications and easier programming – all of it offline and often fully automated – removes this critical barrier to automating.

The modern robotic bending cell requires no robot teaching. The bending software automatically generates the program, factoring bending sequence, tool setup, finger positions and other necessary parameters. The robot software imports all bending data and automatically calculates all gripper positions, considering gripper force, collision detection and robot reachability. This allows full capture of data into the offline software, which aids in and adds to the power and ease of use of offline programming.

Material input is shown here with the use of three pallets. 

This automated programming makes cell setup and operation incredibly easy. Plus, it adds to the overall efficiency and speed of the bending cell. The software is continuously improved and further developed to better support the operator with more automated functions built in. Recently, more features are available to program part stacking.

Quality is assured  

A bending cell equipped with real-time adaptive process control can account for material inconsistencies to assure precision bending with consistent throughput at high cycles times. The system adapts to material variations, including sheet thickness, strain hardening and grain direction, automatically compensating for any changes. This ensures the accuracy of formed parts from the start and repeatable accuracy throughout the bending process, even with changing jobs.   

The Cadman bending software from LVD is another big reason for the productivity found in the company’s next generation of robotic bending cells.

Some bending cells also incorporate a crowning system. Combined with adaptive process control, these features provide a high degree of process stability and consistency.

Take another look

If you turned away from bending automation because it didn’t seem flexible enough for your needs, it may be time for a second look. If you’re ready to do so, consider the following:

  • Part variety and part volumes (daily, weekly, quarterly, annually) matter. You need to ensure the robot can run long enough to gain an advantage. You want enough production volume so that the machine can run two hours without any operator intervention. You don’t want to have to change parts every 45 min.
  • The size of the part influences bending cell selection. You need to consider flat size and complexity. Be mindful that as a flat part is formed, there may not be enough flat areas to grip the part.
  • Part thickness and part weight impact the bending tonnage required. In turn, this directly affects the robot system needed for the parts. Various part thicknesses will require a tooling change, which in all but a fully autonomous cell, is a manual operation.
  • Versatility should be built into the bending cell design. LVD’s Easy-Cell is engineered for batch variety. It features an 80-ton 5-axis hydraulic press brake with a 2,500-mm crowning table and offers multiple grippers, three input pallets and four output pallets. The press brake handles bend lengths up to 2,500 mm and a part weight of up to 25 kg. Cell footprint is small at 8,100 mm by 7,000 mm.
  • Complete a part study verification. Always ask the supplier for a part study to ensure the cell can form the part(s). If a part doesn’t pass the evaluation, the supplier may be able to suggest a part modification that would allow the cell to run the part. An example of this is shown in Figure 1. The formed part is comprised of four finished parts tabbed in place by a connecting center piece. Too small to be handled individually by a robotic system, the parts are combined in a workpiece that can be managed by the robot.
  • Determine how long to run unattended. Run times depend on the size and complexity of the part/job. A complex part could take eight hours to run. There are a lot of variables as to how to schedule the work. That’s why it’s important to complete a part study.
  • Invest in a system that can do double duty, allowing manual operation of the press brake when batch sizes are too small to benefit from automation. In most such bending cells, the press brake retains its full functionality as a standalone machine with no loss of features or capacity.
  • Think about efficiency of flow. Warehousing for the bending cell is a logical next step. With the versatility to handle a variety of parts comes the need to efficiently store flat and finished parts. This could include a pallet dispenser and three-station pallet, which lifts parts on to the centering rack and picks parts off the centering rack, eliminating steps usually required by the robot.
This bending cell from LVD offers robot and manual operation.

The robotic bending cell offers numerous advantages and, if you have parts ready to implement, an ROI in six months to a year. As bending automation continues to evolve and robotic cells increase in versatility, they offer fab shops a way to stay flexible, even with changing orders.

LVD North America

Get industry news first
Subscribe to our magazines
Your favorite
magazines
under one roof