Drive Technology Rising Stars in Full Flight

For ultrasonic testing systems for composite material parts, special requirements apply to drive technology. It’s beneficial when all components come from a single source: servo motors, drive controllers, servo gear units, and a one-cable solution.

The Aldershot-based company Ultrasonic Sciences Limited (USL), with its current 25 employees, specializes in developing and manufacturing customized automated systems for non-destructive testing (NDT). The portfolio also includes PC-based measurement instruments. For around 40 years, USL has been supplying ultrasonic-based NDT systems to a wide range of industries worldwide, including aerospace, automotive, energy, rail, and raw material production, as well as offering related services. The tailored testing solutions are designed for customers focused on high-precision quality control and material composition analysis.

This increasingly affects manufacturers of components and structures made of composite materials in the aerospace industry. The use of this material is steadily rising in the sector, aiming to reduce weight and costs and thereby further enhance efficiency. With the constant optimization of production methods, composite parts are becoming larger and more complex. Crucially, the finished parts must be free of defects—which is why they require more extensive and powerful testing systems.

Niko Bayer, Technical Sales Manager at USL, faced the challenge during the COVID-19 pandemic of finding suitable suppliers who understood how USL operates. These suppliers needed to be capable of customizing each machine together with USL. During his search, Bayer came across Stöber UK. He contacted Martin Preece, the branch manager. When they discussed Stöber's lead times, the Sales Manager discovered that they were significantly shorter than those of competitors. This was exactly the kind of support he needed for his company to fulfill critical orders.

Individually tailored instead of mass-produced

Niko Bayer and his colleagues were tasked with the design, construction, and installation of a twelve-axis double-tower system and an eleven-axis gantry system. These systems are intended to inspect composite components for a long-standing customer in the aerospace industry. Bayer explains: "The custom-made machines are tailored to the application's requirements, flexibility, and scalability. They are precise, powerful, and equipped with special features. This is why they are preferred over standard systems."

"With all of our automated testing systems, we focus on precision, resolution, speed control, torque, load capacity, communication interfaces, safety features, and durability for motion-related components such as motors," explains Bayer. Mechanical systems for automated ultrasonic testing equipment are often subjected to long usage periods, repetitive movements, and frequent directional changes. They are usually also located in humid environments. Bayer adds: "After discussing our requirements with Martin, we were very confident that Stöber would provide exactly what we need for manufacturing our machines."

System tests large and complex parts

For these specific requirements, dual-sided machines were needed for simultaneous through-transmission and pulse-echo testing of composite parts. With large scanning areas and a range of specialized end effectors, powerful and complexly shaped components can be comprehensively inspected. These include, among others, wing leading edges, flap fairings, and thick composite components. All stringent end-user requirements for mechanical precision and ultrasonic testing are thereby met.

An ingenious drive solution

Martin Preece explains: "To meet the demanding project requirements, we discussed various Stöber components. After several conversations with Niko Bayer and the USL team, we were able to specify these." The offered drive systems allowed for seamless integration of components such as servo amplifiers or rack-and-pinion gearing. The solutions include linear and rotary axes with various servo motor sizes from the EZ series. These are very compact and enable maximum torque combined with high dynamics. Additionally, the package features drive controllers of the latest SC6 series, various servo gear units selected for stiffness and precision, as well as the One Cable Solution (OCS), which reliably connects motors and drive controllers over a length of up to 100 meters (approx. 330 ft).

"Our motors and controllers were designed and selected together with USL to optimize performance depending on the type of drive—rack-and-pinion, spindle, or direct drive—and according to the specific requirements," says Preece. Niko Bayer and his team often use a combination of these drives for different axes of the same machine to achieve the desired precision and reliability.

Short lead times and punctual delivery support the collaboration

"Over the years, we have used many different motors and drive controllers from various suppliers," says Bayer. "With Stöber, we get the selection, precision, quality, and reliability that we need for building our machines." Another major advantage of this collaboration: "In our experience, Stöber consistently has shorter lead times and better delivery reliability compared to competitors," Bayer states, adding, "In the past, we used motors that allowed us to implement pre-control values exceeding 100 percent in terms of friction." By anticipating and counteracting the effects of friction, systems with this function can achieve smoother and more precise movements. "When discussing this topic, Stöber was immediately ready to meet our requirements with the SC6 drive controller. This allows pre-control values of up to 200 percent, enabling us to perfectly position our machine axes," says Bayer.

Additionally, Stöber provides integrated servo gear motors without motor adapters. This simplifies installation—thanks to the compact design, lightweight, and high power density. Bayer explains: "The Stöber team is also particularly helpful in specifying machines and supports us in calculating speed, torque, and load. Custom cable lengths offer greater flexibility in designing larger machines."

All requirements for mechanical precision exceeded

Both machines were installed and commissioned at a testing facility for Boeing aircraft structures and components. They exceeded all requirements for mechanical precision. "We are very satisfied with Stöber's solutions and their performance as central components of our machines," concludes Bayer.

USL was able to enhance the performance and reliability of its systems while optimizing its design and manufacturing process. Overall, the synergy between USL's extensive industry expertise and Stöber's components led to the successful implementation of cutting-edge technologies. These meet the ever-evolving requirements of the aerospace industry.

Niko Bayer is enthusiastic about the collaborative partnership with Stöber's branch manager Martin Preece. He ensured that USL received the necessary guidance and support throughout the entire construction and delivery process of the machines. USL was able to seamlessly integrate the system solutions into the automated ultrasonic testing systems. This significantly contributed to the overall efficiency and effectiveness of the processes.