Segmented Compression Chamber for Crack-Free Pellet Removal
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Solution Overview
Problem
The removal of pellets from a compression chamber in pellet manufacturing presses is complicated by differences in expansion coefficients between matrix and powder materials, leading to potential cracking and deterioration of the pellets.
Innovation Solution
A compression chamber design featuring a matrix composed of multiple parts with clamping means that allows the pellet to be extracted by dismantling the matrix around it, using materials with low and similar expansion coefficients, such as tungsten carbide, to minimize stress on the pellet during demolding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the die and pistons are made of materials with different expansion coefficients than the powder material, then the pressing process can be performed, but the removal of the pellet becomes complex and cracks may appear in the pellets
Solution Approach 1:
The die and pistons are made of the same material (tungsten carbide) with identical expansion coefficients, creating a homogeneous system where all components expand and contract uniformly during temperature changes. This eliminates differential stress that would otherwise cause pellet cracking during removal.
Solution Approach 2:
The die is divided into multiple segments that can be separated from each other. During pressing, the segments are clamped together to form a complete die; during removal, the segments can be separated to release the pellet without applying stress to it.
2Strength
If the die is made as a single solid piece, then the structural integrity is high, but the pellet cannot be removed without risk of deterioration
Solution Approach 1:
The die is segmented into multiple parts that can be separated. During pressing, clamping means hold the segments together to provide structural integrity; during removal, the segments can be separated to enable pellet extraction without deterioration.
Solution Approach 2:
The die transitions from a static, solid structure during pressing to a dynamic, separable structure during removal. The clamping means allow the die to change its configuration based on the operational phase, providing both strength during pressing and ease of removal during extraction.
3Ease of manufacture
If conventional materials are used for the die and pistons, then the manufacturing is simpler, but the coefficient of expansion differences cause sticking and pellet damage
Solution Approach 1:
All components (die, pistons, clamping means) are made from the same material (tungsten carbide) with a low and identical coefficient of expansion. This homogeneity ensures that all parts expand and contract uniformly during thermal cycles, preventing sticking and differential stress that would cause cracking.
Solution Approach 2:
The use of tungsten carbide, a composite material consisting of tungsten particles embedded in a cobalt or nickel matrix, provides both the mechanical strength required for pressing and the low, uniform expansion coefficient needed to prevent sticking and pellet damage.
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 design significantly reduces the risk of pellet deterioration by allowing for stress-free extraction, enabling the production of high-quality pellets with reduced risk of cracking, particularly suitable for manufacturing fine multilayer pellets for solid-state batteries.
Implementation Method 1
the elements of which are clamped against each other
Implementation Method 2
heating is applied during the pressing of the material(s) forming the pellet
Implementation Method 3
the first part, the second part and the pistons are made of the same material having a low coefficient of expansion
Data Source
Figure 1~2
Figure 3~5A
Figure 5B~7
AI summary
Compression chamber for a press for manufacturing pellets by pressing powder, said chamber comprising an inner part (14) and an outer part (16), the inner part (14) comprising at least three elements with a cross-section in the shape of an arc of a circle, the outer part (16) comprising a housing with a circular cross-section dimensioned to receive the inner part and to hold the elements (14.1, 14.2, 14.3, 14.4) of the inner part against each other, said outer part (16) comprising two elements (16.1, 16.2) and means for clamping the two elements against each other, an upper piston (10) penetrating the inner part (14) and a lower piston (8) penetrating the inner part (14).