Modern bending automation addresses the needs of both high-volume production and high-mix, low volume situations.
Advancements in automatic tool changing, robot cell technology and software have made automation more practical and cost-effective for bending operations, no matter the size or scope of the workshop.
Reducing manual setups
Automated tool changing press brakes can have a big impact on increasing productivity by reducing manual setups. This is especially true for small batch, high-product-mix environments.
We ask fabricators:
• Are you changing press brake tooling more than six times a day?
• Do your parts require complex or multiple bend stations?
• Are you losing time because of incorrect positioning of tooling sets?
• Are you losing time retrieving tools or searching for tools in use on other machines?
• Is your overall throughput diminished?
If these situations exist, an automated tool changing press brake is worth evaluating.
Automating tool changes
The automated tool changing press brake features an integrated tool storage system. The press brake’s dual-purpose backgauge is used to load and unload tools from the tool storage system. Tool changes are performed following an optimised tool change path. A gripper automatically selects and places the tooling required for the job. The machine unloads the previous tool setup and loads the next setup, quickly, precisely and without manual intervention.
Even complex tool changeovers can be completed in a few minutes. Whilst the operator is preparing parts for the next job, the press brake automatically unloads the previous tool setup and loads the next, ready for production. This frees the operator to do other things, such as prepare for the next job or attend to a nearby punch press or laser.
In some press brakes, the tool storage system can be configured to suit individual application requirements. Recent advancements allow for an even greater variety of tools to be made available to the press brake via the integrated tool storage. Having a large capacity of tools housed within the press brake provides the flexibility to handle a wider range of bending jobs, including complex layouts.
In-process quality control
Most press brake manufacturers offer some form of angle measurement technology. This technology offers several advantages: manual test bending and correcting is eliminated as is the need to check parts within a batch run, scrap is reduced and so is operator involvement. Real-time feedback during the bending process helps ensure accuracy, automatically.
One type of in-process adaptive bending system shown employs lasers to monitor and adapt the angle in real time during bending to achieve +/- 0.3° accuracy. This system does not look at the bend and apply a correction afterwards, so there is no interruption in the bending cycle.
Beware of any adaptive system that significantly increases cycle time. A true real-time angle measurement system provides feedback to the machine control for positioning of the ram to produce an accurate bend without secondary compensation. Systems that do not operate in real time take a measurement of the angle at a ram position above what is required to create the bend. From the measurement taken, the system then calculates the final position to create the accurate bend angle. This all takes time, which significantly slows the cycle and offers little advantage over the traditional trial and error method.
Robotised bending
Electric-drive press brakes are ideal for bending small parts in large volumes at high speeds. This efficiency lowers the cost-per-part.
Coupling an electric press brake with an industrial robot advances this productivity, allowing unmanned operation and the capacity to handle small, complex parts in varying batch sizes. When producing a large series of small parts, this bending cell can operate unattended for up to eight hours. The bending cell also features a universal gripper that accommodates part sizes from 25 mm x 100 mm up to 300 mm x 400 mm. Because one gripper fits all applications, production is continuous and uninterrupted. Users can make bends on three different sides of a part without regripping. Gripper suction cups are controlled via offline software and activated according to part size.
Today’s robotised bending cell is different from the robotic bending systems of the past that integrated a hydraulic press brake to a standard robot arm. These systems required robot teaching and a significant investment of time for bending setup in order to realise the productivity advantages of automation. They were also usually much less compact than today’s bending cells.
Software advancements
Software advancements have cut programming time for the press brake and the robot. Full network connectivity and more intuitive control of the machine also helps make tool setup more efficient. Parts can be programmed offline and 3D-simulation files can be seamlessly transferred to the machine ready for production. This minimises the art to part time. In the case of a bending cell, CAM generation of the bending and robot program can take just 10 minutes with another 10 minutes for setup and first part generation
Why automate bending?
Whether you’re bending small or large parts, small or large quantities, or high-mix parts, advancements in automated bending technology are providing more automation choices suitable for a wider range of applications. With automation more accessible comes the temptation to over-automate. Beware, doing so can negatively impact your cost per part. Be sure that the ratio of cost of the automation is not more than twice the cost of the stand-alone machine. This keeps the direct cost of the part at an ideal level.
Words by Neil Osborne, Sales Director, LVD (UK) Ltd