Laser measures the full 3D contour of forged specimens heated up to 1,200 °C
After leaving the forging press, the warm forgings are placed in the measuring cell.
At the METEC, nokra is presenting the alpha.hot3D system for the 3D laser measurement of hot forged parts for the first time. It makes it possible to predict cold dimensions within a few seconds after forging. In this way, the forming process can be checked and immediately optimized after the first parts.
In forging, it is of critical importance to profit and loss to know as soon as possible after the first pieces are formed, whether they will meet the specified dimensions once they have cooled. Until now, depending on the size of the forgings, you have to wait up to two hours until they have cooled down sufficiently for a measurement with a coordinate measuring system. By then, a modern hot press may have produced many thousands of parts that may not meet geometric specifications.
The new alpha.hot3D system from nokra records the complete contour of test specimens heated up to 1,200 °C and calculates the dimensions of the parts in the cold state with an accuracy of up to 25 µm: The forging process can start just a few seconds after the first part has been formed be optimized.
The system is so compact that it can be installed on the operating platform of the forging press – the hot forgings are inserted directly from the conveyor belt into the measuring cell immediately after leaving the forging press. The measurement starts at the push of a button, the cold measurement result – “OK” or “NOK” – including the display of the characteristics and the target/actual comparison is available after a few seconds. The test item can then be fed back into the process.
The system passed the acid test when measuring rotationally symmetrical parts on a hot press. The cold dimensions calculated by alpha.hot3D were compared with those of a coordinate measuring system. The deviations were between 5 and 20 µm and were therefore significantly lower than the user had expected.
Günter Lauven, the managing director of nokra GmbH, sees great potential for the new system: “Especially for smaller batch sizes, the investment in our system pays off very quickly, because a fault in the tool is all the more important. And if measurements are taken at regular intervals during the process, that brings additional security.”
The technology in detail
alpha.hot3D measures the complete 3D contour of warm workpieces. Up to four nokra laser light section sensors record the 3D geometry while the warm workpiece rotates 360° in the measuring cell. Another sensor measures the temperature of the test object.
Various algorithms calculate the geometric features configured in the test plan from the contour values. Another determines the respective cold dimensions based on the measured temperature. The system is trained for each type of forging so that the prediction of the cold gauge is precisely adapted to the respective part type and its characteristics. The algorithm not only takes into account the general thermal expansion of the material, but also the shape of the parts, because some areas cool down faster than others.
The first system built accommodates parts with a diameter of 130 mm x 115 mm, systems for component sizes up to 185 mm x 190 mm are in preparation; it is so compact that it can be placed on the operator’s platform of the press.
nokra at METEC 2023
Dusseldorf, June 12th to 16th, 2023:
Halle 1, Stand B29
About nokra
nokra GmbH is an international company that offers high-quality measuring and testing systems for use in production. The systems record and check geometric features such as length, width, thickness, flatness, profile, shape and position.
nokra develops and produces the necessary laser sensors and automated testing systems itself. This means that a standard system can be quickly optimized for the respective application. nokra has extensive expertise in dealing with metrological issues in the steel, aluminum and automotive industries, plant construction, the plastics industry and car glass processing.
company contact
nokra Optical Testing Technology and Automation GmbH
Gunter Lauven
Robert-Koch-Strasse 6
52499 Baesweiler
+49 2401 6077-10
http://www.nokra.de
Press contact
VIP Communication
Regina Reinhardt
Dennewartstraße 25-27
52068 Aachen
+49 241 89468-24
http://www.vip-kommunikation.de