Segmented Screw Extrusion for Honeycomb Clay Pulsation
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Solution Overview
Problem
Conventional extrusion-forming devices face issues with clay accumulation and pressure pulsation during the manufacturing of ceramic honeycomb structures with thin walls, leading to reduced article quality and increased extrusion pressure, resulting in defects such as cracks and strength decreases.
Innovation Solution
The extrusion-forming device features a drum with a screw having supply port side and extrusion port side screws with specific ratios of pitch to diameter and lengths, along with a forming portion with forming grooves, allowing for controlled extrusion pressure and reduced pulsation, enabling efficient production of honeycomb structures with thinner walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the amount of clay to be supplied is increased to improve productivity, then productivity is improved, but extrusion pressure rises causing clay accumulation and quality degradation
Solution Approach 1:
The screw is divided into multiple sections with different pitch values: a first screw section with a first pitch and a second screw section with a second pitch. This segmentation allows different regions of the screw to perform different functions - the first section handles clay conveyance while the second section controls extrusion pressure, thereby maintaining quality despite increased productivity
Solution Approach 2:
Different portions of the screw are given different local characteristics through varying pitch values. The first screw section has a first pitch optimized for conveyance, while the second screw section has a second pitch optimized for pressure control. This local differentiation enables the system to handle both high productivity and quality requirements simultaneously
2Shape
If the partition walls in the honeycomb structure are thinned to advance densification, then the forming grooves become more compact, but resistance to clay increases causing extrusion pressure rise and pulsation
Solution Approach 1:
The screw is segmented into multiple sections with different pitch values to independently control clay conveyance and extrusion pressure. This allows the system to handle the increased resistance from compact forming grooves without experiencing harmful pressure pulsation, enabling production of thin-walled honeycomb structures
Solution Approach 2:
The pitch parameter of the screw is varied across different sections to optimize both conveyance and pressure control. By changing the pitch from the first section to the second section, the system adapts to the increased resistance from thin-walled forming grooves while maintaining stable extrusion pressure
3Productivity
If extrusion pressure rises with increased clay supply, then productivity improves, but clay accumulates in the drum causing quality degradation
Solution Approach 1:
The screw is divided into a first screw section for conveyance and a second screw section for pressure control. This segmentation prevents clay accumulation by ensuring that the second section actively manages and regulates pressure, allowing continuous extrusion at high productivity levels without drum accumulation
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 configuration allows for precise and efficient manufacturing of ceramic honeycomb articles with compact cells and thinner walls, preventing clay accumulation and pressure pulsation, thereby enhancing the quality and productivity of the formed articles.
Implementation Method 1
a screw having a rotary shaft and a spiral rotary blade disposed along the rotary shaft and configured to convey the clay in an extruding direction parallel to the rotary shaft while kneading the clay by the rotation of the rotary blade
Implementation Method 2
a forming portion including a die through which the clay is extruded and which has forming grooves arranged in a forming face
Data Source
AI summary
An extrusion-forming device includes an extruding portion having a drum including a supply port through which a clay flows into the inside, a screw having a rotary shaft and a rotary blade and configured to convey the clay, and an extrusion port through which the clay is discharged; and a forming portion having a die provided with forming grooves. The device includes, as the screw on the side of the supply port, supply port side screws having two rotary blades and, as the screw on the side of the extrusion port, a extrusion port side screw having one rotary blade, and a ratio P/D is in a range of 0.5 to 0.9.