Dry-Formed Cellulose Moulding for Uniform Density Patterns
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Solution Overview
Problem
Existing dry-forming techniques for manufacturing rigid cellulose products with non-flat shapes and decorative/functional small-patterns face challenges in achieving optimal density and preventing fibre release or yellowing due to inconsistent pressing forces, leading to unsatisfactory material characteristics.
Innovation Solution
A product forming unit with mould parts having controlled projections and recesses, where the height and depth of patterns relative to the nominal thickness are limited to 15% or less, ensuring optimal density and preventing fibre release and yellowing, using a predetermined pressure to achieve a density of 1035-1265 kg/m³.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If dry-forming techniques are used to manufacture rigid cellulose products with decorative patterns, then time and energy consumption are reduced, but fibre release and yellowing occur due to inconsistent pressing forces
Solution Approach 1:
The mould part is designed with different surface regions: a first region with projections for decorative patterns and a second region with a recess for functional patterns. Each region applies localized pressing forces to specific areas of the cellulose blank, ensuring uniform density and preventing fibre release or yellowing in different zones of the final product.
Solution Approach 2:
The pressing surface is segmented into multiple functional zones (first region with projections, second region with recess) that independently control different aspects of pattern formation. This segmentation allows precise control of pressing forces applied to different parts of the cellulose blank simultaneously.
2Shape
If projections and recesses are added to mould parts for pattern formation, then decorative and functional patterns are achieved, but manufacturing precision is compromised due to variable pressing forces
Solution Approach 1:
Different regions of the mould part have different geometries (projections vs recess) optimized for specific pattern types. The first region creates decorative patterns through projections while the second region creates functional patterns through recess, with each region's geometry precisely controlled to maintain uniform pressing forces and consistent density across the cellulose product.
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
The solution enables the production of cellulose products with uniform material characteristics, maintaining environmental benefits and reducing time and energy consumption, while achieving decorative and functional patterns without fibre release or yellowing.
Implementation Method 1
press the cellulose blank therebetween into final shape by applying a predetermined pressure P in the axial direction of the moulding tool
Implementation Method 2
the cellulose fibres are bonded to each other using heat and pressure
Data Source
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AI summary
The present invention relates to a method and a product forming unit for dry manufacturing rigid cellulose products (2) having essentially non-flat general shape from a cellulose blank. The product forming unit comprising a moulding tool having a first mould part (15) and a second mould part (16), wherein at least one of the first mould part (15) and the second mould part (16) is displaceable in the axial direction in relation to the other in order to press the cellulose blank therebetween into final shape by applying a predetermined pressure P in the axial direction of the moulding tool. The nominal distance (T) between the first mould part (15) and the second mould part (16) is in the range 0,3-2,0 millimetres. The first mould part (15) comprises a projection (30) that has a height (H) equal to or less than 15% of said nominal distance (T), in order to provide a debossing pattern (31) on the pressed cellulose product (2), and a recess (32) that has a depth (D) equal to or less than 15% of said nominal distance (T), in order to provide an embossing pattern (33) on the pressed cellulose product (2), wherein the essentially even principal surface (29) of the second mould part (16) is opposite said projection (30) and said recess (32) of the first mould part (15).