Polymer Technology Group

Slit die Rheometer

The benefit of slit die rheometer is that the Bagley correction is not required to obtain the true shear stress. Pressure is measured along the slit geometry using up to three flush mounted pressure transducers, which enables direct determination of the shear stress.
For equivalent polymer volumetric flow rates, the rectangular geometry will yield lower maximum shear rates than those of a capillary, but consistent with those expected in extrusion. It is a modular construction allowing easy use of different slit die measuring geometries. The slit geometry itself is machined into a changeable insert, meaning that only the insert has to be changed if a variation in either slit height or width is required. This construction allows great flexibility over slot dimension and thus shear rate.