Green Sheet Permeability Measurement
Original Publication Date: 1985-Jun-01
Included in the Prior Art Database: 2005-Feb-18
This apparatus provides a method of measuring relative green sheet permeability (leakage) for process control of the physical properties of cast green sheet to improve screening yields. Solenoid valve 1 is opened, filling chamber 2 with nitrogen gas, then closed. The fixed volume of nitrogen gas contained in chamber 2 leaks through green sheet 3 and porous backing plate 4. The time required for nitrogen gas to leak through the green sheet 3 is measured by electronic pressure transducer 5, voltage comparator 6, electronic timer 7 and digital readout 8. The reading indicated by digital readout 8 provides an inverse measure of green sheet permeability. Chamber 2 is forced against green sheet 3 (under test) by an air cylinder 9 and sealed with soft silicone rubber gasket 10.