Imprintec Material Testing Solutions is an expert in the field of mechanical materials testing. The company uses white light interferometers from Isra Vision for its testing devices, offering its customers maximum accuracy and fast measurement results.

The i3D series testing machines from Imprintec are used, among other things, to carry out strength tests for the unambiguous identification and quality control of materials. They are also used for component testing and for local inspection of heat treatments, hot forming or weld seams, for example. Another area of application is the investigation of strength curves of partially press-hardened sheet metal components, which are used in the automotive industry, among others. Imprintec uses the indentation method in accordance with DIN SPEC 4846, in which a minimal, punctual test indentation is generated under force control and then the indentation and the surrounding impact are measured optically in three dimensions. Thanks to sophisticated algorithms and FEM simulations, material properties such as yield curve and yield strength, tensile strength and hardness value can be determined quickly and precisely from the data obtained.

"Optical measurement is a sub-step of the test procedure at Imprintec. High demands are placed on measurement and repeat accuracy. Lateral resolution also plays a decisive role," says Peter Zok, Application Consultant at Imprintec. To achieve this, NetGage3D white light interferometers from Isra Vision are used in the devices. They deliver reliable and fast 3D measurement results and thus ensure short inspection times. Another decisive factor for the use of the sensors was the possibility of individual customization, according to Peter Zok: "As part of the cooperative collaboration with Isra Vision, the optical sensors could be configured to suit our inspection devices. This simplified integration enormously. The sensors used measure three-dimensional surfaces of up to 200 mm² in a short space of time. This is a considerable technological advantage over conventional point or line sensors."

The NetGage3D sensors are based on the principle of white light interferometry, in which a measurement object and a reference mirror are evenly illuminated by white light. The reference mirror and measurement object reflect the rays back into the camera. Depending on the height structure and object surface, different path lengths are created for the reference and sample light. These superimposition patterns are evaluated by software and a distance is calculated for each object point. This results in a topographical image of the sample in the form of a height map. The coaxial arrangement of the measuring light and camera lens means that depths such as boreholes, trenches and etched structures can be measured with high precision. The repeatability of the measurements with standard systems at a step height of 50 µm is typically around 100 nm, with an absolute accuracy of ±200 nm. Variants with increased accuracy are also available.

In addition to the technical properties and the customer-specific configuration of the sensors, Imprintec also opted for the NetGage3D sensors because of the simple connection to the overall system, says Peter Zok: "The easy-to-integrate interface allowed us to program the sensor ourselves. This was a great advantage for integration into our inspection systems."

As a result, Imprintec was able to launch a compact device for mechanical quality assurance of components and materials in accordance with DIN SPEC 4846 in a very short development time, which customers can use to reliably and precisely determine the mechanical properties of their products - and thus increase quality, improve process reliability and minimize rejects or complaints.