The tolerance between the teeth is 0.030" and extremely high rates in the 32,000 reciprocal second
This is called shear thinning, and the rate of deformation of the paint as it is sheared is called the shear rate (units are reciprocal seconds
However, such curves provide mainly relative moldability comparisons; the u n its of measurement (Pascal-seconds for viscosity and reciprocal seconds
for shear rate) are of no practical value in judging a resin's process window.
Riley, consultant at Extrusion Engineers in Branchburg, New Jersey, will compare tests of lubricants and plastics at impossible shear rates exceeding 1 million reciprocal seconds
Inkject printers, for example, subject ink to shear rates in the range of 100,000 to 1,000,000 reciprocal seconds
The shear rate is the relative velocity of the bottom and top cared (cm/sec.) divided by the thickness of the deck (cm), to yield units of reciprocal seconds
"In recent work we used sliding speeds on the order of microns/sec, though with a separation of only five angstroms, it turns out you get a rate on the order of [10.sup.5] reciprocal seconds
. Eventually we want to get to rates 1,000 times faster."