Use of acoustic emission testing in injection moulding process

摘要

This paper presents the experimental results regarding acoustic emission signals measured during the injection moulding of those standard test specimens commonly used for examining the shrinkage behaviour of various thermoplastic materials. The acoustic emission was measured on a new injection mould and injection mould with the visible cracks on the cavity's surface. Two resonant 150 kHz piezoelectric AE sensors were attached to tool steel inserts via AE waveguides. The results of acoustic emission testing on the crack defected tool steel insert revealed higher acoustic emission activity compared with that captured on the brand new engraving insert under same processing conditions. Specimens produced with a new and defected tool were scanned with an optical 3D digitiser. Results of the experiments confirm that acoustic emission measuring during injection moulding of polymer materials is promising technique to characterise integrity of injection moulding tool regarding occurrence of cracks.