THE ANALYSIS OF DOUBLE-ACTION PRESS SLIDER MOVEMENT

The complex sheet parts forming uses double-action presses with an external slider for clamping the workpiece. The quality of sheet metal parts depends on many factors, including the equipment parameters. The part forming shows the external slider displacements during clamping. The kinematics of the multi-link double-action press mechanism affects these displacements. The external slider movement during clamping leads to the clamping force changing and, as a result, to folding. To determine the kinematic displacement of the external slider during clamping, the authors analyzed the kinematics of the press multilink mechanism. The solution proposes a mathematical model of the double-action press kinematics. The authors built a wire-frame CAD-model of the press working parts and, using NX Siemens PLM Software, analyzed its kinematics. It allowed building a cyclogram of the external slider movement and finding the crankshaft rotation angle interval for clamping. This interval contains several local extrema. To find the exact value of the slider displacement in the lower position, the authors built the system of nonlinear displacement equations. Such a system did not have an analytical solution; therefore, its solution was found with numerical analysis. For the local extrema points, the authors found the nonlinear system solutions and obtained the displacement extremal values using the MATLAB software. The study showed that to prevent folding, it is necessary to set the gap between the clamp and matrix, taking into account the kinematic displacement of the external slider during clamping, which can amount up to 1/3 of the thickness of a workpiece of the exterior parts of a vehicle.

sheet metal double-action presses, external press slider, kinematic analysis, constrained extremum task, CAD/CAE modeling, cyclogram, multi-link mechanism