Robot-Based 3D Inline Inspection

In response to this market situation, LASS Technology developed the FlexScan system. Originally designed with a focus on dimensional measurement, it was then consistently refined technically into a fully integrated solution for geometry inspection, weld seam analysis, and optical component inspection directly on the production line. A special feature is not only the bundling of several inspection tasks in a single inspection process, but also fully automated continuous operation without operator intervention.

“Our goal was to create a measurement system that works independently of humans and still delivers the highest accuracy even under harsh production conditions,” explains Hüseyin Bozan, CTO of LASS Technology. “FlexScan is our answer to the need for true 100% inspection in mass production lines.”

The result is a customizable, robot-assisted 3D laser scanning system that inspects both individual parts and complete car bodies quickly, reliably, and in a validatable manner inline.

To implement this application, LASS Technology relied on a strong technology trio: AT Sensors, EVT Eye Vision Technology, and its own system expertise. As one of the leading component manufacturers for image processing, AT Sensors supplied the high-precision 3D sensor technology, EVT wrote the powerful and yet flexible image processing software, and LASS Technology finally took over the robot-assisted system integration.

However, there were a few hurdles to overcome during the development of this application. One of the biggest challenges in developing FlexScan was the enormous variety of variants. Different component geometries, changing inspection tasks, and individual customer requirements called for a system that could be flexibly configured yet still run stably over the long term.

“A fully automated system must function reliably in every situation, without downtime, without readjustment, without room for interpretation,” says Bozan. The development time reflects this requirement: three years of prototyping, one year of application optimization, and over eight years of continuous system and software development with a growing installed base.

To implement the various inspection tasks in the FlexScan system, AT proposed the simultaneous use of two different compact 3D sensors from the 2040 line. The 2040CS is considered a reliable all-rounder sensor in the AT portfolio: With a field of view of 63 mm, a resolution of 31 µm in the X-axis and an impressive 0.9 µm in Z, it combines high resolution with a profile speed of 43 kHz. The blue laser provides a particularly clear signal, which proves ideal for fast inline measurements of geometry and weld seams. The 2040CS with a 63 mm field of view is complemented by the 2040CS with a 100 mm field of view, which is used for larger profile measurements and multi-sensor calibrations. With a resolution of 49 µm in X and 3 µm in Z, it offers the necessary flexibility for large-volume components.

“For us, the image quality of the sensors is the decisive factor,” emphasizes Dr.-Ing. Athinodoros Klipfel, Head of Sales at AT Sensors. “Only a low-noise, stable signal makes it possible to systematically reduce measurement uncertainties in complex robot-assisted applications and achieve reproducible results.” The decision to use components from AT Sensors was not a random one for LASS Technology. In addition to resolution and speed, the robustness, signal stability, and extremely low noise characteristics of the sensors were particularly convincing.

“The quality of the recorded profiles significantly reduces our development effort,” explains Bozan. “The better the raw signal, the more stable and efficient the evaluation software can work.”

The complete evaluation of the data is controlled by the EyeVision software from EVT Eye Vision Technology. EVT deliberately relies on standard software that can be individually customized using graphically combinable command modules. An additional special command was developed for weld seam inspection, while surface and geometry inspection is implemented entirely with standard functions.

“Our goal is to make powerful image processing as easy to use as possible,” says Michael Beising, CEO of EVT, who has been working with LASS Technology for more than nine years and emphasizes the customer’s keen interest in innovative, globally applicable solutions. “Once a setup has been properly configured, it can be reproduced worldwide and operated reliably over the long term.” Depending on the configuration, the system achieves an accuracy of 0.05 to 0.15 mm and a repeatability of 0.04 to 0.12 mm, depending on the robotics and sensor resolution.

FlexScan impressively demonstrates how modern 3D sensor technology, powerful image processing, and sophisticated system integration can work together. Thanks to the system’s high measuring speed, true 100% inspection is possible without affecting the production flow. At the same time, the modular and customer-specific system design allows precise adaptation to different component geometries, cycle times, and production environments. This allows FlexScan to be seamlessly integrated into existing production lines and flexibly adapted to new requirements. The combination of AT Sensors, EVT Eye Vision Technology, and LASS Technology is therefore exemplary of the change in industrial quality inspection: away from humans and toward stable, automated processes and thus to measurably better quality. Or, as Dr.-Ing. Athinodoros Klipfel from AT Sensors sums it up: “Automated inspection is no longer a trend; it is a prerequisite for sustainable production quality.”