Tie-bar elongation in plastic injection molding machines is a side-effect that can have useful implications.

Tie-bar elongation is proportional to the clamping force in mechanical toggle clamping systems. Depending on the machine size and clamping force, during ordinary operation the actual extension can be up to 2 mm (0.08″). This relatively large mechanical movement leads to an interesting application for Balluff BAW analog inductive displacement sensors. A high-resolution analog device for measuring small displacements of metal targets, the Balluff BAW can detect the extention of the tiebar in-process, providing continuous measurement of the clamping force without the need for expensive instrumentation.

Control of Clamping Force with BAW PDF