Canadian press brake manufacturer Accurpress created its first tandem press in response to a customer’s request. The customer didn’t want to buy an expensive custom machine with the sole purpose of bending longer parts, which would rarely have operated at full capacity.

The end result was anything but an awkward monolith taking up space. The company, with a manufacturing location in Surrey, B.C., set out to develop a tandem machine by coupling two of its Accell press brakes, using the “master and slave” principle.

“It was clear to us that the coupling should be via the control system,” says Alex Kvyatkovski, R&D team leader at Accurpress, referring to the machine’s PC-based control from Beckhoff Automation. His team achieved the coupling with Beckhoff through real-time Ethernet. To switch from simplex to tandem, all the operator has to do is select tandem mode on both machines, specify which is “master” and which is “slave,” and upload the recipe to be processed to both control computers.

In tandem mode, the two machines operate as one and can bend sheet metal components with a length of up to 14 metres. Beckhoff control technology synchronizes the two machines and controls the bending process, including the associated material handling equipment.

Each press has a C6240 control cabinet industrial PC (IPC) from Beckhoff using Windows as operating system, and the TwinCAT automation software platform. Beckhoff CP7037 control panels with TFT displays are used as the human-machine interface (HMI). EtherCAT links the input/output (I/O) level with the control system.