Isostatic Mould Oil Volume Control for Uniform Ceramic Compaction

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Solution Overview

Problem

Existing isostatic ceramic moulds face issues with oil aging, leakage, and uneven compaction due to constant oil volume, leading to premature wear, irregular powder distribution, and defects in the final product.

Innovation Solution

An apparatus with a volumetric metering device that controls the precise volume of oil in the mould, adding oil only during compaction and removing it afterwards, ensuring isostatic pressure without constant oil presence, and utilizing an elastic membrane adherent to the metallic body for uniform compaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If oil is continuously present in the mould air space to maintain isostatic pressure, then uniform compaction is achieved, but oil aging and chemical-physical degradation occur leading to premature membrane failure

Engineering Contradiction:
Improveuniform compactionVSAvoidmembrane life
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies periodic action by introducing oil into the mould only during the compaction phase when isostatic pressure is needed, and removing it afterwards. This cyclic presence-absence of oil maintains compaction quality while preventing continuous exposure that causes aging and degradation, thereby extending membrane life.

Inventive Principle:
Principle #19Periodic action

2Stress or pressure

If oil volume remains constant during the moulding cycle, then isostatic pressure is maintained, but leakage and losses occur modifying punch behavior and causing transparency phenomena

Engineering Contradiction:
Improveisostatic pressureVSAvoidpunch behavior stability
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The patent implements feedback control by monitoring oil volume in the mould and automatically replenishing it to maintain optimal levels. This closed-loop approach ensures consistent isostatic pressure while compensating for leakage and losses, preventing transparency phenomena and maintaining stable punch behavior throughout the mould's lifetime.

Inventive Principle:
Principle #23Feedback

3Stress or pressure

If membrane swellings are used to counter pressing pressure, then isostatic compaction is achieved, but irregular powder distribution and compaction differences occur during loading

Engineering Contradiction:
Improveisostatic compaction pressureVSAvoidpowder distribution uniformity
Core Design Contradiction:
Stress or pressureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by introducing oil into the mould before the compaction phase begins, allowing the membrane to pre-form its swelling configuration. This advance preparation ensures that when powder loading occurs, the membrane is already in the optimal state to provide uniform isostatic pressure, preventing irregular powder distribution and compaction differences.

Inventive Principle:
Principle #10Preliminary action

4Ease of operation

If membrane swellings project beyond mould matrix during ejection, then elastic action aids tile extraction, but localized wear and deterioration occur due to rubbing

Engineering Contradiction:
Improvetile ejectionVSAvoidmembrane durability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent extracts the harmful rubbing action by controlling oil volume to be removed after compaction. This prevents membrane swellings from projecting beyond the mould matrix during ejection, eliminating the rubbing that causes localized wear and deterioration, while maintaining sufficient membrane elasticity for successful tile extraction during the compaction phase.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution prevents oil-related degradation, ensures uniform compaction, reduces defects, and extends mould life by maintaining optimal oil conditions during the pressing cycle.

Implementation Method 1

The filling of the air space by means of oil occurs by adjusting the pressure inside the punch, causing an elastic deformation of the membrane which remains in contact with the top of the grid

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a volumetric metering device adapted, at every pressing cycle, to insert a precise and desired volume of oil in the punch

Methodology Applied
Scientific EffectVolumetric measurement:

Data Source

PatentEP1716998B1Compaction control apparatus and method by means of isostatic moulds
Publication Date: 2011.09.07 SACMI COOPERATIVA MECCANICI IMOLA SOC COOP ARL
  • EP1716998B1 patent drawingFigure 1

AI summary

Control system of the compaction of the powder in a ceramic mould by means of a punch of isostatic type comprising an air space within which a quantity of oil is situated which is sufficient to support the elastic pressing membrane, in which said air space, at every compaction cycle, is placed in communication with a tank (6) and a pump (7) of feeding by means of a volumetric metering device (5) which sends the desired quantity of oil to the air space of the mould, said metering device being associated with detection and reading means (56) of the oil quantity sent to the mould air space, and being associated with valve means (81, 82, 83) of delivering, blocking and discharging the oil to the, in the, and from the mould air space, to ensure the presence in said air space of a prearranged oil volume for every step of the compaction cycle.