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Browse Prior Art Database

Dynamic Sheet Deflection Measurement Tool for Monitoring Green Ceramic Sheet Dryness

IP.com Disclosure Number: IPCOM000049342D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Desai, KS: AUTHOR [+5]

Abstract

In this tool, the solvent concentration in a green ceramic sheet, which is directly related to the rate of sag of the sheet supported on space supports, is detected by optical techniques.

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Dynamic Sheet Deflection Measurement Tool for Monitoring Green Ceramic Sheet Dryness

In this tool, the solvent concentration in a green ceramic sheet, which is directly related to the rate of sag of the sheet supported on space supports, is detected by optical techniques.

Dryness testing of large and densely screened green sheets is required prior to stacking the MLC (multilayer ceramic) layers because inadequate sheet dryness may cause substrate delamination during the sintering operation. The dryness of the green ceramic screened sheet is defined as the amount of retained paste solvent by the screened layer after the normal paste drying cycle. It has been discovered that the rate of sag of a screened green ceramic sheet 10 supported on space low friction rods 12 is directly related to the solvent in the sheet. In this apparatus, a light source 14 shines a beam of light across the top surface of the green sheet and causes a shadow 16 to be projected across a transducer 18 provided with a vertical aperture 20. The transducer 18 transforms the light to dark transition of the shadow edge into electrical signals.

Further processing, i.e., sampling, amplification and logic, results in a numerical count which indicates in real time the distance the shadow has traveled since the start of the cycle. If the green sheet edge is close to the transducer and the light source is kept at a small positive angle above the horizontal plane of the green sheet, the deflection of th...