Sensors and electronics accelerate development

Balancing machine from 1963. © Schenck Rotec

The process remained largely unchanged until the 19th century. It was not until 1870 that the first balancing machine was mentioned. In 1881, the entrepreneur Carl Schenck founded the Carl Schenck Eisengießerei & Waagenfabrik. Balancing machines were also produced there from 1907. This was also the starting signal for today's Schenck RoTec GmbH from Darmstadt. The company acquired the license for the balancing machine patented by engineer Franz Lawaczeck in 1908.

"From then on, all technical improvements were heavily dependent on sensors, measurement technology and later increasingly on electronics and microprocessors," says Marc Frisch, Technical Sales Manager at Schenck RoTec. The first sensors were developed as early as the 1920s to measure vibrations and thus detect unbalance. At that time, however, measuring the angular position of the unbalance on the rotating body was still problematic. It was only with the so-called watt-metric method from the 1940s that angles and unbalance parameters could be precisely determined. However, the measuring devices were still very large and heavy at this time and therefore not easy to transport. This changed in the 1960s and 1970s with the advent of transistor technology.

Balancing machines are becoming more intelligent

Balancing machines already existed at the beginning of the 20th century. Here is a device from 1912. © Schenck Rotec

At the end of the 1970s, development then took the next important step. With programmable pocket calculators, users were able to solve balancing algorithms that they had previously had to calculate graphically by hand. This meant that the measured values were plotted on a sheet of paper - a polar diagram - and the unbalance was determined from the vibration and calibration values using an iterative, graphical process. Not only was this very time-consuming, but only a few specialists were able to do it. The increasing availability of pocket calculators then made balancing much easier. With the advent of microprocessor technology, programmable pocket calculators could be integrated into the machines so that the device itself calculated the unbalance and its position using a balancing algorithm. In addition, the displays and display options of the measuring devices continued to improve. While initially only certain key figures - such as vibration, magnitude or phase - could be displayed, graphical display options were increasingly added in the 1990s. On the new monitors, the unbalance could be displayed in polar coordinates - a significant help for the balancer. Gradually, the measuring devices became faster and more accurate, the displays became colorful and the values could be saved. And today? Users save the measured values and either transfer them to a stationary computer or use IIoT solutions such as Schenck One. This makes machine data available worldwide, ensures more efficient processes and machines can be used and maintained better and more cost-effectively.

Where will operational balancing go from here?

"I think that from today's perspective, as in many other areas, the basic technology for operational balancing is largely mature. The technology could still be developed further, but in practice no user would notice. The next big step is optimization, not just of the machine, but of all balancing processes. And we are already on the right track with the software and digitalization of our products," says Frisch. The next milestones could include, for example, further simplification of the operating systems for an operating balancer.

An analog vibration transducer from 1920. © Schenck Rotec

Measurement technology itself is very complex. It may be possible to simplify this in the future. Another interesting point is the optimization of condition monitoring. The aim here is to be able to make predictions about the condition of machines. For example, when the bearing is likely to fail because certain characteristics can be seen in the vibration curve. The new machines collect data that is centralized via a cloud connection and which the maintenance technician has an overview of. The data can therefore be called up in the control center or on a mobile device. Despite all the technology and improvements, balancing is still a matter of know-how. The technology can only ever be as good as the person operating it. And sometimes the conditions for operational balancing are less than ideal: the machine may exhibit resonances, unexpected operating conditions or non-linearities. In such cases, an experienced balancing professional from Schenck RoTec can be very helpful in providing support.

A gallery with historical pictures of balancing machines and measuring devices can be found here.