Ceramic Green Sheet Thickness Measurement Inversion

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for measuring the thickness of ceramic green sheets in the green sheet process are prone to errors due to mechanical inaccuracies and variations, leading to unreliable measurements and reduced yield, especially when different layers require varying thickness accuracy.

Innovation Solution

A measuring equipment with fixed measurement bases and digital micro gauges that move in synchronization with the stage, allowing for precise thickness measurement at multiple positions without mechanical errors, and a method to classify green sheets based on average and variation in thickness for optimal layer selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a contact type probe using a micro gauge or a noncontact type probe using a laser beam is used to measure the thickness of the green sheet, then the measurement can be performed efficiently, but mechanical inaccuracies and variations in the moving mechanism cause errors of 2 to 3 μm, reducing measurement reliability

Engineering Contradiction:

Improvemeasurement efficiencyVSAvoidthickness measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical moving stage system with a fixed stage and movable probe system. The probe is moved vertically to contact the green sheet surface for measurement, while the stage remains stationary and fixed. This substitution eliminates mechanical errors from stage movement, guide rails, and linear guides, achieving submicron measurement accuracy without sacrificing measurement efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If the same thickness accuracy requirement is applied to all green sheets in the lamination, then measurement consistency is maintained, but severe process control is required and yield deteriorates when some layers can tolerate larger variations

Engineering Contradiction:

Improvethickness accuracy consistencyVSAvoidyield

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent implements local quality by allowing different thickness accuracy requirements for different layers in the lamination. The measurement system provides accurate data for each green sheet, and the lamination process can then assign appropriate tolerance levels to specific layers based on their functional requirements. This enables higher yield by not unnecessarily rejecting green sheets that meet the sufficient (though not stringent) requirements for particular layers.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If the stage is moved to measure multiple positions of the green sheet, then comprehensive thickness measurement is achieved, but mechanical errors from the moving mechanism are superimposed on the thickness variation

Engineering Contradiction:

Improvecomprehensive thickness measurementVSAvoidmeasurement reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent inverts the conventional approach by keeping the stage fixed and moving the probe instead. The probe is positioned vertically above the fixed stage and moved to contact the green sheet surface at different positions. This inversion eliminates the source of mechanical errors (stage movement mechanism) while still enabling comprehensive measurement at multiple positions, thereby maintaining measurement precision and improving reliability.

Inventive Principle:

Principle #13The other way round (Inversion)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances measurement accuracy to submicron levels, enabling higher yield in laminated body production by allowing varying thickness tolerances across layers, reducing the need for severe process control and improving overall production efficiency.

Implementation Method 1

a probe 108p of a digital micro gauge 108 is brought into contact with the green sheet 107 from the upper side of the green sheet 107, to thereby measure the thickness of the green sheet 107

Methodology Applied

Scientific EffectMechanical displacement detection:

Data Source

PatentUS8359761B2Measuring equipment and method for forming laminated body

Publication Date: 2013.01.29 NGK INSULATORS LTD

AI summary

A method for improving an accuracy of measurement of the thickness of a green sheet, and additionally improving yield of a green sheet used for formation of a laminated body is provided. The thickness of each of a plurality of ceramic green sheets is measured, and an average and a variation of obtained thickness measurement values are checked against predetermined ranking criteria. Thereby, a ranking is performed in which the plurality of ceramic green sheets are classified into a plurality of ranks set in the ranking criteria. When forming the laminated body, only a ceramic green sheet belonging to at least one of the ranks which is in advance allowed to be used is used as a ceramic green sheet constituting each layer of the laminated body.