In the shape of iQsmartbend, WAFIOS has developed a patented, award-winning software solution designed to optimize bending processes for wire and tubes

The phenomenon of vibrations can be observed in almost every area of our daily lives. In some cases it is undesirable and may even be dangerous, but in others, it is the intended result of a conscious action. Intervening measures can be put in place in both cases, as a means of either absorbing (or at least minimizing) vibrations in the former case, or generating (or amplifying) them in the latter. The pendulum of a grandfather clock and the swinging-out motion of the seats on a fairground swing ride are both examples of controlled, stimulated vibrations.

One example of where absorption can be found is in the tuned mass dampers used in high-rise structures. Installed in buildings such as the Taipei 101 tower, which measures 500 meters in height, dampers of this kind absorb building vibrations - particularly those caused by wind, but also those caused by earth tremors or human influences - and prevent the building from rocking. As a result, they serve a dual purpose: both ensuring the building remains safe and providing comfort for its inhabitants. Another example can be found in construction cranes. The natural vibrations that occur in the boom, cable, and load need to be balanced out so that the boom can position the load in exactly the right place. Then there are the controlled and guided vibration movements created in a wrecking ball.

Analytical calculations and control systems can be used to minimize or absorb vibrations in tuned mass dampers, wrecking balls, and cranes, but the vibrations that affect CNC machines are subject to many influencing factors that rule out methods of this kind.

When long wire and tube parts are being shaped, the workpieces frequently vibrate heavily due to the process. This means that the required quality can usually only be achieved by manually adjusting (in other words, slowing down) each individual bending step. This is a time-consuming, cost-intensive process. Generally speaking, conventional criteria such as flexibility, output rate, and quality are used to assess how profitable a wire-bending machine is. In many cases, however, it is not the machine itself that is the limiting factor, but rather the geometry of the bent part. Significant vibrations can occur in long bent parts with slim geometries as the process means that an increasing amount of the bent part's mass hangs freely in the air each time a bending step is completed. Not only can these vibrations cause unwanted deformation in areas of wire that have already been bent, but excessively strong swinging motions can also lead to the wire springing out of the tool that is open at the top: Fig. 1 shows an example of this. The machine operator is left with just two options for achieving the required stability in the bending process: either reduce the speed of the work or factor in waiting times. Both strategies, however, have a negative impact on the machine's output rate. Up to now, it has not been possible to find a solution in which an optimization algorithm, operating by means of a direct link between the production machine and a computer, is able to automatically reduce or even eliminate the natural vibrations that the bent part experiences.

In wire-based applications, examples of bent parts of this kind can be found in structural parts for car seats, oil dipsticks, and engine hood holders; and in tube-based applications, they can be found in all types of thin fluid lines such as brake fluid and oil lines.

With the aim of maximizing machine production output while maintaining - or even improving - quality levels, WAFIOS has developed iQsmartbend, providing a technique that optimizes axis traversing paths to such an extent that vibrations are significantly minimized as a result. The iQsmartbend optimization is started at the push of a button in the WAFIOS Programming System EasyWay. The part geometry, machine parameters, and material parameters are transmitted all the way to Reutlingen, reaching WAFIOS' cluster center by means of a VPN. The received data packet then triggers an automatic program sequence designed for optimization. This algorithm generates a number of parameter sets that define the various potential traversing movements of the axes. The cluster defines the process step and saves the vibrations once the process is complete. The optimization algorithm evaluates the results, making it possible to specify parameters with maximum efficiency for the next calculation procedure. This process is repeated until a geometry-dependent stop criterion is reached. Once all the steps in the bending process have been optimized, the algorithm selects the parameter set that will produce the best result in respect of duration and residual vibration. The data is automatically returned to the machine and transferred directly to the WAFIOS EasyWay control program. The entire calculation procedure takes a matter of minutes; see also Fig. 2. 

iQsmartbend not only helps achieve an increase in quality and output thanks to the reduction in wire vibrations in the process, but also provides a direct link between the production machine and the optimization algorithm.

With iQsmartbend, it is possible to bring about an active reduction in the vibration properties of bent parts and boost output through achieving a higher bending speed. Its basic premise involves the tool absorbing or stimulating vibrations in the component during the bending process in order to ensure that as little residual vibration as possible remains at the end. The tool motion profiles are optimized virtually and automatically, then transmitted to the WAFIOS EasyWay control system. This results in an NC program that enables active vibration reduction. Taking the material parameters into account, the software preselects NC parameters for each process step (see Fig. 3). 

• Immediately apparent to the user are the huge time-saving benefits achieved thanks to the lack of lengthy tooling times, and the higher machine availability that goes hand in hand with this. The online interface to WAFIOS AG enables automatic optimization via the WAFIOS cluster within just a few minutes.
• When the bending process is optimized, tooling time is eliminated, and the number of rejects is reduced, an increase in output follows as a natural consequence. This increase falls somewhere within the upper two-digit percentage range (< 60%) depending on the bent part being used.
• With less handling work involved, there are also fewer quality requirements for the operator to meet. The operator sets up the bent part only with regard to tool traversing paths, collision, and geometry. Acceleration and speed values are automatically generated in the NC program.
• Fewer production machines and a smaller footprint are required for the batch size (order volume).
• Different targets can be set in the production network according to the requirements being placed on the bent part. When selecting target variables for the optimization algorithm, it is possible to focus on output, part quality with respect to size accuracy, or a best-fit approach that combines both output and part quality.
• The system is self-learning, with the option of deriving empirical speed and acceleration values from the database. These values can then be developed into a self-learning optimization algorithm system.

Summary and outlook
Through iQsmartbend, WAFIOS is providing a technique that calculates the best machine parameters for the bending sequence and transfers them directly to the WAFIOS EasyWay machine control system. Not only can it lead to a clear reduction in set-up times, but it is also possible to boost output significantly depending on the bent part geometry, while maintaining or increasing the required part quality. The hybridization presented here involves data transfer, external computing power (WAFIOS), and optimization algorithms especially developed for the machines, and will be available for WAFIOS wire and tube machines in the future. iQsmartbend is one of the building blocks of WAFIOS' "Smart Factory 4.0" initiative. The company presented the concept and the first solutions developed for it at the 2016 Wire & Tube trade fair in Düsseldorf, Germany, with the motto "Smart Factory 4.0 - Experience Tomorrow's Production Today". WAFIOS is expanding the Smart Factory element of the Industry 4.0 concept by adding new business models, such as coupling production and services using iQsmartbend (hybridization). The iQsmartbend technique for reducing wire vibration has been patented by WAFIOS AG.