In the successfully completed ZIM collaborative project ApproxiSens with industry partner KB Prüftechnik GmbH, a novel measurement system for hardness testing machines was developed that raises industrial hardness measurement to a new level of quality. Traditionally, hardness is determined by driving an indenter into a test specimen with a defined force and speed. Hardness is then determined from the ratio of force to penetration depth.
To increase cost-effectiveness, the indenter is now approached at the highest possible speed. Therefore, the goal of the project was to accelerate the indenter’s approach phase to the test specimen’s surface without risking damage to the material or the equipment. To this end, a measurement system was designed that determines the distance to the test specimen and precisely controls the point of contact. It can be fully integrated into the tool turret and combines highly sensitive force transducers with pressure sensors that measure the distance to the test specimen during the approach phase. Thanks to the improved sensitivity and the ability to regulate the increase in force at the moment of contact, the test force can be precisely controlled over a very wide measurement range. In addition, compressed-air nozzles have been developed that, together with a stop plate, form a nozzle-stop-plate system, further optimizing distance measurement at close range. This system allows the indenter to be moved at a high feed rate and then slowly decelerated once the desired distance is reached—an approach that significantly reduces the risk of collisions.
The advantages for industrial applications are numerous. The accelerated approach allows for increased throughput in serial measurements, while precise distance measurement and controlled force ramp-up improve the reliability and repeatability of the results. The modular design allows for easy integration into existing testing machines, enabling manufacturers to immediately benefit from these advantages without having to fundamentally overhaul their equipment. The technology can also be used in the fields of materials research and manufacturing monitoring, making it equally attractive to research institutions and production lines.
R&D Collaboration Project:
ApproxiSens: Development of a hardness tester for test loads up to 1 gf using a force transducer with a nonlinear spring and a nozzle-impact plate system for detecting the distance between the indenter and the test specimen down to 1.0 μm, enabling faster Vickers hardness testing in 1 os
Subproject:
ApproxiSens: Development of a force transducer with a nonlinear spring and a pneumatic nozzle-impact plate system for reliable measurement of the force rise at the point of contact and for distance detection between the indenter and the test specimen up to a distance of 10 μm
Funding code: KK5085704EW1
