Next-generation tube bending machines

Incorporating a real-time Ethernet control system architecture, and a major new release of programming and control software, the machines take the advanced shape forming capability and flexibility of servomotor-controlled bending to a radical new level. The new UK-built Breeze machines bend faster, exploit advanced multi-axis synchronisation capabilities to support very sophisticated roll-forming, improve the tool adjustments that can be employed during the bending cycle to generate ultra-precise part shapes, and offer a visual collision checking programming feature as standard. They also feature an open architecture that is easily adapted to integrate application-specific capability or build work cells.

An all-electric architecture provides tube benders with significant performance benefits in terms of set-up speed, repeatability, lower energy consumption and noise reduction compared with traditional hydraulically powered machinery. Unison pioneered all-electric tube bending in the 1990s, and has played a seminal role in establishing the trend that today sees software-controlled, servomotor-based bending machines the number-one choice for virtually all small-to-medium diameter applications involving high precision, small batch sizes, and expensive tubing materials.

At the heart of Unison's new Breeze machine range is a real-time machine and motion system based on the deterministic Ethernet-compatible Powerlink protocol. A 100 Mbits/second network links all of the servomotor drives required to control bending operations. The speed of the network makes it possible to coordinate the movement of the various servomotor axes used during bending - such as the carriage, plane of bend, and clamp roller - more rapidly, allowing Unison to improve the speed of bending for many common tasks by typically around 10%.

The quality of bend shapes and wall thickness can also be improved thanks to finer real-time control over the motion profiles used by key bending axes which move as the rotary draw bending process takes place - such as the carriage and the follower die. Real-time interpolation of multiple axes is also supported by the machine's new motion control architecture. In particular, this allows Unison to equip machines with extremely flexible roll-forming tools that are able to vary the radius of bending with great precision during the bending cycle. Other benefits include much-improved diagnostics and data collection which can assist with both programming and maintenance, and easy connection to factory networks for changing programs, reporting production metrics, etc.

Unison is also releasing major new programming and operating software for the tube benders. Among dozens of new and improved features in v10 of its Unibend package is a collision checking capability that helps users to program the machine for new parts. Bending operations are visualised using a 3D model of the machine. If users see any potential collision problems, bend sequences can be reversed, and intervening carriage and rotation movements can be employed to ensure the part can be manufactured easily. Programming itself can be achieved typically in a couple of minutes by entering new ISO, XYZ or YBC values (distance tube is pushed out, rotation, and degree of bend), linking from CAD or measuring machines, adapting an existing template, or interactively teaching the machine.

The versatility of Unison's software-controlled tube bending machinery is very high, and this attribute is improved by the new networked control architecture. Almost all tube bending machines are configured around a base design to suit the user's intended applications, including or excluding facilities as required. Unison is currently seeing a substantial increase in demand for work cells that integrate tube bending with other processes. The new Ethernet architecture provides almost unlimited flexibility for configuring and building integrated machines and cells: the control network can be very long allowing physically large processes to be accommodated with ease; and one network controller can handle up to hundreds of motion axes and other control system resources such as sensors. The networked nature of the control system architecture makes it easier to upgrade systems later in their lifecycle, to integrate processes such as loading, end forming and unloading for example.

"In a word, this new architecture gives us more versatility. Users are looking to increase the degree of automation of processes, to cut costs and allow them to hire from a wider pool of labour," adds Alan Pickering of Unison. "The major upgrades to software and hardware embodied in this release give us a more versatile and finely programmable platform. This makes it possible to give customers no-compromise packages that deliver exactly what they require, and offer upgrade capability during the machine's lifetime."

Unison can supply the new architecture on all-electric tube bending machines capable of handling tubing with diameters up to 180 mm (7 inches). Machines can be fitted with single- or multi-stack tooling, and with two or more bending heads.