Scale-invariant kinematic comparison of pressure-plate drives in die-cutting presses using a unit nit displacement invariant

This paper presents an invariant-based framework for scalable kinematic comparison of pressure-plate (platen) drive mechanisms used in die-cutting presses. The maximum platen stroke is adopted as a unit displacement invariant (λS=1), enabling displacement, velocity, and acceleration to be expressed in dimensionless form as functions of the main-shaft angle. Four drive architectures (including wedgingand slider-based layouts) are evaluated using contact-interval metrics defined by a normalized displacement threshold (Si(φ)≥0.98). The proposed approach highlights distinct motion-law features, including asymmetric strokes and long dwell ("plateau") behavior in the contact zone, which is critical for embossing/creasing operations. To validate the analytical invariants, a closed-loop workflow is implemented: mechanism geometry is synthesized in Python, transferred to SolidWorks via automated parameter transfer, and verified using Motion Study results exported to CSV. Experimental acceleration measurements acquired at constant shaft speed further confirm the characteristic shape features of the predicted curves. The presented methodology provides a practical, scale-consistent tool for mechanism selection and motion-law tuning in press applications.