Proven Technology, New Application: EMG SOLID® DFT

Laser-Induced Fluorescence Measurement: Innovation Meets Practicality

The EMG SOLID® DFT employs laser-induced fluorescence (LIF), a technique that leverages the interaction of laser light with varnish molecules. When a UV laser excites the varnish molecules, they emit fluorescence radiation unique to their chemical composition. This emitted radiation is then captured and analyzed to determine the thickness of the varnish layer with remarkable accuracy.

The system’s advantages lie in its ability to measure also extremely thin layers (from 0.2 µm on) without physical contact inline. By evaluating the fluorescence signals over a signal intensity over time analysis, the EMG SOLID® DFT distinguishes between desired measurement data and background noise. This precision not only enables the measurement of diverse coating types but also ensures adaptability to various varnishes and production conditions. Unlike infrared (IR) methods, which struggle with surface roughness and texture, LIF offers robust performance across diverse substrates without extensive recalibration.

Streamlined Installation, High Efficiency

An important feature of the EMG SOLID® DFT​​​​​​​ is its straightforward installation. The sensor heads, compact in size (35 mm diameter, 180 mm length, and weighing less than 0.5 kg), are designed for seamless integration into production lines, even in confined spaces. The system’s modular frame allows for cross-web measurement in a traversing mode, capturing data across the coil width and length, thus creating a detailed coil map of coating thickness variations.

This adaptability is further enhanced by the system’s compatibility with higher temperature environments. Inline tests have demonstrated accurate measurements at strip temperatures of up to 150 °C, directly after the drying furnace, equivalent to the quality of measurements taken at 50 – 70 °C in subsequent stages of the process. Such capabilities reduce material waste by identifying coating anomalies very early in the process, minimizing the production of defective coils.

Once set up, the system operates autonomously, offering real-time, inline measurements with minimal maintenance requirements.

Moving Beyond Radioactive Methods: A Cleaner and Sustainable Future

Traditional methods for measuring varnish thickness, such as beta backscattering (BBS), rely on radioactive isotopes like Promethium. While effective, these methods pose significant challenges, including regulatory compliance, environmental concerns, and declining isotope availability. Furthermore, BBS is unsuitable for measuring modern varnishes like self-bonding products and C6 coatings.

The EMG SOLID® DFT​​​​​​​ eliminates these drawbacks entirely. By adopting LIF technology, production facilities can transition to a non-radioactive, environmentally friendly solution. This shift not only aligns with global sustainability goals but also reduces operational risks associated with handling radioactive materials.

The benefits extend beyond compliance and safety. LIF technology offers superior measurement sensitivity, detecting varnish thickness fluctuations as minute as 0.1 µm — capabilities unmatched by BBS or IR systems. This heightened precision ensures consistent quality, enhances process control, and supports the production of high-performance electrical steel strips.

Transforming Electrical Steel Production

The EMG SOLID® DFT​​​​​​​ system marks a significant leap forward in insulation thickness measurement technology for electrical steel products. By leveraging the proven capabilities of laser-induced fluorescence, known for years from EMG SOLID® LIF, it provides production engineers and managers, as well as quality assurance teams with an accurate, reliable, and environmentally sustainable tool for inline monitoring. With its ease of integration, robust performance across diverse conditions, and elimination of radioactive materials, the EMG SOLID® DFT​​​​​​​ system sets a new standard for precision and efficiency in electrical steel quality management. For manufacturers aiming to stay competitive in a rapidly evolving market, this innovation offers a clear path towards improved quality control, reduced waste, and enhanced operational sustainability.

Curious for more details?

Should you require further information, please directly contact EMG’s product management via timo.gemmer@emg-automation.com​​​​​​​. To explore the full potential of EMG SOLID® DFT for your production needs, please visit the product webpage at: EMG SOLID® DFT.