Shearing force is the effort required to get the ink from the top of the screen to the bottom of the screen. There are two types of shearing force: shear-stress, force perpendicular to the mesh which is the traditional form of ink transfer; and shear-rate, the more efficient force parallel to the mesh, which is the core of high-shear transfer.
It is always best to use shear-rate (think stroke speed) as to minimize the use of shear-stress (think pressure). With shear-stress transfer, we need to search endlessly to find that magical point between fluid pressure and fluid volume, which most often occurs at a slower stroke speed. With shear-rate transfer, fluid volume, pressure, and speed all run parallel. Accordingly, faster is better, and we can use speed to regulate deposit.
Source: Joe Clarke