Dry-Formed Cellulose Rim Shear-Cutting for Clean Edge Definition
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Solution Overview
Problem
Existing dry-forming techniques for manufacturing rigid cellulose products with non-flat shapes face challenges in achieving a distinct and well-defined rim, as they often result in frayed edges, loose fibers, and aesthetic and mechanical property issues due to high cutting forces and improper cutting methods.
Innovation Solution
The method and apparatus involve a cutter body in the second mould part that is axially displaceable to perform a shear-cut on the rim of the cellulose product after it is fixed by the mould parts, ensuring the rim is trimmed independently of the forming process, using a biased cutter body to minimize cutting force and prevent material draw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional dry-forming techniques are used to manufacture rigid cellulose products with non-flat shapes, then production speed and energy efficiency are improved compared to wet-forming, but the rim quality deteriorates with frayed edges, loose fibers, and poor aesthetic appearance
Solution Approach 1:
The moulding tool is segmented into distinct functional zones: a central mould body for forming the main portion and a surrounding cutter body for trimming the rim. This segmentation allows the rim trimming operation to be performed independently with precise control, preventing the rim quality deterioration that occurs in conventional unified moulding approaches while maintaining the efficiency benefits of dry-forming
Solution Approach 2:
The cutter body is positioned to perform rim trimming before the final pressing operation. By preliminarily shaping and trimming the rim while the cellulose material is still relatively compliant, the method achieves precise rim definition and prevents fraying that would occur if trimming were delayed until after final forming
2Manufacturing precision
If high cutting forces are applied during rim trimming in conventional dry-forming, then the rim shape can be defined, but the mechanical properties of the rim deteriorate with material draw, miscoloration, and fiber damage
Solution Approach 1:
The cutter body applies localized trimming forces only to the rim portion surrounding the central mould body, rather than applying uniform high forces across the entire product. This localized approach achieves precise rim shape definition while minimizing mechanical damage, material draw, and miscoloration that would result from generalized high-force trimming
Solution Approach 2:
The cutter body is designed with axial displaceability, allowing dynamic adjustment of cutting depth and pressure. The cutter can be positioned at optimal depths during different stages of forming, applying appropriate forces to achieve clean cuts without excessive pressure that would cause fiber damage and strength loss
3Device complexity
If the cutter body is fixed in position during forming, then device complexity is reduced, but the ability to achieve well-defined rim deteriorates due to inability to perform independent rim trimming
Solution Approach 1:
The moulding tool is divided into a central mould body and a surrounding cutter body that can move independently in the axial direction. This segmentation adds only minimal complexity while enabling the cutter to perform independent rim trimming operations, achieving well-defined rims without the complexity of fully integrated multi-axis systems
4Loss of time
If rim trimming is performed concurrently with main portion forming, then process time is reduced, but rim quality deteriorates due to interference between forming and cutting operations
Solution Approach 1:
By segmenting the moulding tool into a central mould body and a surrounding cutter body with independent axial movement, the invention enables sequential operations where the cutter can trim the rim at optimal times during or after forming without interfering with the main portion shaping, achieving both time efficiency and rim quality
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 results in a well-defined, aesthetically pleasing and mechanically robust rim with reduced loose fibers, avoiding material draw and miscoloration, while maintaining energy and time efficiency.
Implementation Method 1
The cutter body of the second mould part is configured to cause a shear-cut together with the rim portion press-surface of the first mould part
Implementation Method 2
final pressing of the rim portion of the cellulose product into final rigid shape between the rim portion press-surface of the first mould part and the rim portion press-surface of the second mould part
Data Source
Figure 1
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AI summary
The present invention relates to a method for dry manufacturing rigid cellulose products. A rim portion press-surface (29a) of a first mould part (18) is arranged opposite a rim portion press-surface (25a) of a second mould part (19) in order to press the rim portion of the cellulose product therebetween, wherein a cutter body (32) is displaceable in the axial direction in relation to the rim portion press-surface (29a) of the first mould part (18) and the rim portion press-surface (25a) of the second mould part (19) between a retracted position and an extended position. The method comprises the steps of: engaging the rim portion on opposite sides by the rim portion press-surface (29a) of the first mould part (18) and the rim portion press-surface (25a) of the second mould part (19), displacing the cutter body (32) of the second mould part (19) in relation to the first mould part (18), in order to cut-off residual cellulose material located radially outside the rim portion, and thereafter final pressing of the rim portion into final rigid shape between the rim portion press-surface (29a) of the first mould part (18) and the rim portion press-surface (25a) of the second mould part (19).