Tool-Endurance of High-Speed Stamping Tools with Plates of Magnesium and Carbon Fibre Laminate

Because of high gating velocities in high-speed blanking tools there is a recurring acceleration at the moment, when the blank holder contacts the sheet metal and when the sheet cracks. Through these impulses a periodic oscillation arises in the tool. Horizontal vibrations can lead to an undefined position between punches and die-plates, while vertical movements leads to increased wear because of friction forces between the blanked surfaces and the lateral area of the punches. The paper describes a project to minimize these oscillations in cutting tools by the usage of the lightweight materials aluminium, magnesium as well as carbon fibre laminate instead of steel as plates in the flux of forces. With a high effort in design and construction as such a high-speed experimental tool for cutting-out nine circular blanks with diameters of 0.60 mm, the effect of lightweight materials on the oscillation behaviour of the tool could be investigated. The integration of the sensors for force, acceleration and distances allowed a recording of the oscillation-effects during the blanking process. With a structural analysis of the relevant parts in the tool, two frequencies could be assigned to a tilting and a tension eigenmode. Practical tests are also done up to frequencies of 1000 strokes per minute and 300'000 strokes for each tool-setup.     «

Because of high gating velocities in high-speed blanking tools there is a recurring acceleration at the moment, when the blank holder contacts the sheet metal and when the sheet cracks. Through these impulses a periodic oscillation arises in the tool. Horizontal vibrations can lead to an undefined position between punches and die-plates, while vertical movements leads to increased wear because of friction forces between the blanked surfaces and the lateral area of the punches. The paper describe...     »