Acoustic Process Monitoring during Transient Precision Forging of High Strength Components  Full text 

V. Böhm¹, O. Bruchwald¹, W. Reimche¹,Fr.-W. Bach¹, D. Odening², B.-A. Behrens²

¹Institute of Materials Science, Leibniz University Hanover
² Institute of Metal Forming and Metal Forming Machines, Leibniz University Hanover

UDC 621.773

Metall. Min. Ind.,  2011, Vol. 3, No. 7, pp. 91-97

Abstract

The structure-borne sound, displacement and continuous acoustic emission measuring systems provide new possibilities for detecting very short term transient events over a broad frequency range during the precision forging of gear toothed parts such as gearwheels and pinion shafts. It is also possible to analyse these events by employing wavelet analyses over these frequency ranges. With the aid of these methods, the compressivedeformation, flow and frictional processes as well as the die-filling were evaluated during precision forging by selectively using the displacements and frequencies in order to recognise early damage and to sensitively monitor the forging process. The influence of the temperature, lubrication and impurities on the forming behaviour and on the quality features of the precision forged high strength components were recorded and assessed during the process sequence. A novel sensitive monitoring technology for transient production processes with respect to early damage recognition resulted from analysing the signal profiles using the wavelet transformations of a feature and vector analysis.

Keywords: STRUCTURE-BORNE SOUND MEASUREMENTS, DISPLACEMENT MEASUREMENTS, ACOUSTIC EMISSION MEASUREMENTS, WAVELET, PRECISION FORGING, GEARWHEELS, PINION SHAFTS, EARLY DAMAGE RECOGNITION, DIE-FILLING, QUALITY ASSESSMENT