Ceramic Extrusion Torque Control via Segmented Liquid Addition

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Solution Overview

Problem

The existing methods for manufacturing ceramic formed bodies face challenges in maintaining stable viscosity and shape retention during extrusion, leading to variations in product shape and increased torque, which affects production efficiency and roundness.

Innovation Solution

A method involving the addition of liquid at two stages: wet mixing and kneading, allowing for continuous processing and integral kneading and forming steps, with real-time shape measurement to adjust liquid addition, ensuring balanced fluidity and shape retention, thereby stabilizing torque and product shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If liquid is added at one time during wet mixing, then the additive ratio of liquid to forming raw material can be increased to reduce torque and improve fluidity, but the raw materials will not be mixed uniformly, making it difficult to prepare a homogeneous forming raw material

Engineering Contradiction:
Improveproduction efficiency for extrusionVSAvoidhomogeneity of forming raw material
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The liquid addition process is segmented into two distinct stages: first adding a predetermined amount of liquid during wet mixing, then adding the remaining liquid during the kneading step. This segmentation allows each stage to perform its specific function - wet mixing establishes initial homogeneity, while kneading completes the mixing with additional liquid to achieve optimal fluidity without compromising uniformity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A predetermined amount of liquid is added in advance during the wet mixing step to establish initial homogeneity of the raw materials. This preliminary action prepares the mixture in a controllable manner before the additional liquid is introduced during kneading, ensuring that the foundation for uniform mixing is already in place.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the additive ratio of liquid to forming raw material is increased to reduce torque during extrusion, then production efficiency improves, but the viscosity control becomes difficult and shape retention deteriorates

Engineering Contradiction:
Improveproduction efficiency for extrusionVSAvoidshape retention and roundness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The liquid addition process is made dynamic and adjustable across two stages. The first stage adds a base amount of liquid during wet mixing, while the second stage adds remaining liquid during kneading. This dynamic approach allows optimization of both torque reduction and viscosity control by adjusting the timing and amount of liquid addition at each stage, rather than adding all liquid at once.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The viscosity and fluidity parameters of the forming raw material are controlled by changing the liquid addition parameters - specifically, adding liquid in two stages rather than one. This parameter change approach allows achieving the optimal balance between low torque (requiring higher liquid content) and good shape retention (requiring controlled viscosity).

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If liquid is added in small amounts during wet mixing to maintain homogeneity, then mixing uniformity is achieved, but the additive ratio of liquid remains limited, causing high torque during extrusion

Engineering Contradiction:
Improvehomogeneity of forming raw materialVSAvoidtorque during extrusion
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The liquid addition is segmented into two phases: a controlled initial amount during wet mixing to maintain homogeneity, and a subsequent amount during kneading to increase the total liquid ratio. This segmentation resolves the contradiction by separating the homogeneity function (wet mixing stage) from the fluidity function (kneading stage), allowing both goals to be achieved.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The liquid addition process continues across two consecutive steps - wet mixing and kneading - rather than being completed in one step. This continuous action ensures that homogeneity is established first, then fluidity is optimized, maintaining useful action throughout the material preparation process to achieve both mixing quality and extrusion efficiency.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3075718B1Method for manufacturing ceramic formed body
Publication Date: 2019.06.19 NGK INSULATORS LTD
  • EP3075718B1 patent drawingFigure 1
  • EP3075718B1 patent drawingFigure 2

AI summary

Provided is a method for manufacturing a ceramic formed body enabling the manufacturing of a ceramic formed body having a controlled product shape, such as roundness, by keeping the torque applied to the extrusion machine stable and low, using a forming raw material having well-balanced fluidity and shape-retaining property. A manufacturing method 1 includes: a dry mixing step S 1 of dry mixing a raw material 3 by batch processing; a wet mixing step S2 of adding liquid 5 to a dry mixture 4 obtained at the dry mixing step S1, the liquid including at least one type of water, surfactant, lubricant and plasticizer, while wet mixing; a kneading step S3 of kneading a wet mixture 6 obtained at the wet mixing step S2; and a forming step S4 of extruding a kneaded mixture (forming raw material) obtained at the kneading step S3 to make a ceramic formed body 2. In the kneading step S3, the liquid 5 is further added during kneading of the wet mixture 6.