Increased precision in the mounting and the running-in process of sheet metal forming tools with use of the non-destructive testing method acoustic emission

Mounting and adjusting of tool parts or correction of blank holder forces in deep drawing operations can be optimised by minimising acoustic emission due to influence of boundary layer friction and wrinkling. Critical friction surfaces can be monitored with consideration to the wear of the friction surfaces. The momentary acoustic emission contains information about the status of wear at the friction surfaces and if the wear is a wear-in or a wear-out process.

Unexpected events like fractures and galling results in distinct and abnormal increase in acoustic emission. The acoustic emission contains information that can be used to improve or monitor the forming operation. These conclusions are results from studies of different forming operations and measuring of acoustic emission in the forming tool both at the productions lines at the sheet metal forming industry and laboratory tests at Lund University.

The author professor Jan-Eric Ståhl is responsible for the education of Masters and doctoral degree at the department of Production and Materials Engineering, Lund University. He has long experience of applied research in the area of mechanical engineering. Thomas Skåre, PhD, is lecturer in mechanical engineering at the Kristianstad University College and has experience from the area of production engineering and acoustic emission.