Metal forming processes are pivotal in manufacturing, but they suffer from wear and tear of tools leading to a demand for precise monitoring. The latest research published in the journal Sensors presents a novel approach that integrates a 3D measuring endoscope with a two-stage kinematic system, advancing the maintenance of sheet-bulk metal forming tools. This in-depth article examines the implications of this development, its contribution to the field, and the future prospects it holds.


In the world of manufacturing, particularly in the realm of metal forming, efficiency and precision are paramount. In the continuous quest for innovation, researchers have developed a new method for monitoring the health and precision of metal forming tools. The research, carried out by Lennart Hinz, Markus Kästner, and Eduard Reithmeier from the Institute of Measurement and Automatic Control at Leibniz University Hannover, and published in Sensors journal, addresses challenges in monitoring highly stressed geometries in tools used for sheet-bulk metal forming processes. Their work, supported by the Deutsche Forschungsgemeinschaft within CRC TR 73, is outlined in the following news article, which will provide an insight into the research’s background, methodology, and findings, as well as its impact on the industry.


Maintenance of metal forming tools is critical to the long-term success and efficiency of manufacturing operations. Traditional methods of tool inspection tend to be time-consuming and may not offer the level of precision needed for today’s high-standards. In light of this, the research by Hinz et al. (DOI: https://doi.org/10.3390/s19092084) explores the potential of using a 3D measuring endoscope combined with computer-aided design (CAD) data for accurate measurement and registration of forming tools. This combination seeks to enhance maintenance by providing timely and comprehensive data.

Research Methodology

Hinz, Kästner, and Reithmeier’s research utilizes a method based on structured light projection to take several hundred measurements across a tool’s surface. These measurements are then registered and merged into a single point cloud that provides a detailed 3D representation of the tool’s geometry. The challenge lies in achieving precise alignment of the heavy and unwieldy specimens, where even slight misalignments can cause significant errors. The research adopts CAD-assisted registration to minimize these errors and ensure that the tool’s shape deviations are accurately detected.

Research Findings

The study confirmed that the CAD-assisted approach to registering measurements taken by the endoscope significantly improved the accuracy of tool monitoring. The researchers could identify local features and shape deviations with much greater precision than traditional methods. This CAD integration serves not only to enhance the accuracy of measurements but also to potentially reduce the time needed for inspection, as it streamlines the process of alignment and data collection.

Impact on Industry

The application of this research could have a profound impact on the sheet-bulk metal forming industry. The ability to perform timely and accurate maintenance checks means that tool lifespans can be extended, and product quality can be maintained without the need for constant tool replacement. It enhances both the efficiency of operations and the end product’s reliability.

Future Prospects

This innovative method opens up new avenues in the field of metrology and maintenance. Looking forward, it is feasible that similar systems could be developed to cater to a wider range of manufacturing tools and processes. The integration of 3D measuring endoscopes with CAD-assisted registration may soon become a standard for high-precision tool monitoring across various sectors.


In conclusion, this advancement in tool monitoring technology reflects the ongoing evolution of manufacturing maintenance processes. With the development of this 3D measuring endoscope system and CAD-assisted registration, the manufacturing industry moves one step closer to realizing the goal of maximizing efficiency and precision. The implementation of such technologies holds the promise of significantly improving production processes, quality control, and tool longevity in the demanding world of metal forming and beyond.


1. Weckenmann A., Krämer P., Hoffmann J. Manufacturing Metrology—State of the Art and Prospects. Proceedings of the 9th International Symposium on Measurement and Quality Control, Madras, India, 21–24 November 2007; pp. 1–8.
2. Frankowski G., Hainich R. DLP-Based 3D Metrology by Structured Light or Projected Fringe Technology for Life Sciences and Industrial Metrology, Proceedings of the SPIE MOEMS-MEMS: Micro- and Nanofabrication, San Jose, CA, USA. 24–29 January 2009.
3. Merklein M., Allwood J.M., Behrens B.-A., Brosius A., Hagenah H., Kuzman K., Mori K., Tekkaya A.E., Weckenmann A. Bulk forming of sheet metal. CIRP Ann. 2012;61:725–745. doi: https://doi.org/10.1016/j.cirp.2012.05.007.
4. Gröbel D., Schulte R., Hildenbrand P., Lechner M., Engel U., Sieczkarek P., Wernicke S., Gies S., Tekkaya A.E., Behrens B.A., et al. Manufacturing of functional elements by sheet-bulk metal forming processes. Prod. Eng. 2016:63–80. doi: https://doi.org/10.1007/s11740-016-0662-y.
5. Geng J., Xie J. Review of 3-D endoscopic surface imaging techniques. IEEE Sens. J. 2013;14:945–960. doi: https://doi.org/10.1109/JSEN.2013.2294679.


1. Metal Forming Tool Monitoring
2. 3D Measuring Endoscope
3. CAD Assisted Registration
4. Structured Light Projection
5. Sheet-Bulk Metal Forming