Cellulose Blank Compression Zoning for Crack-Resistant Deep Drawing
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Solution Overview
Problem
Traditional cellulose product forming methods using air-formed blank structures face issues such as undesired breakage, cracks, fibre separations, and material fractures, especially for deep-drawn products, leading to low-quality outcomes.
Innovation Solution
A method involving a forming mould system with defined product and residual sections, where the residual section is compressed to a higher degree than the product sections, and cutting patterns form bridging structures to facilitate transportation and insertion, allowing for higher feeding speeds and improved product quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional air-formed cellulose blank structures are used for deep-drawn products, then production simplicity is maintained, but structural weaknesses occur leading to breakage, cracks, and fibre separations
Solution Approach 1:
The cellulose blank structure is divided into multiple sections with different compression degrees. Product sections (where products will be formed) have lower compression to maintain flexibility and prevent breakage, while residual sections (non-product areas) have higher compression to provide structural support during handling and feeding. This segmentation allows the blank to withstand the demands of deep-drawn forming without breaking or developing cracks.
Solution Approach 2:
Different regions of the cellulose blank structure are given different local properties through selective compression. The product sections maintain a more open, flexible fiber structure suitable for forming, while residual sections are compressed to provide rigidity and strength for handling. This local differentiation of material properties prevents uniform structural weaknesses while maintaining overall integrity.
2Productivity
If uniform compression is applied to the entire cellulose blank structure, then handling stability is improved, but feeding speed is reduced due to increased risk of breakage
Solution Approach 1:
The blank structure is segmented into product sections and residual sections with different compression levels. The less compressed product sections maintain flexibility and resistance to breakage during high-speed feeding, while the more compressed residual sections provide overall structural stability for handling. This enables higher feeding speeds without sacrificing structural integrity.
3Manufacturing precision
If high forming pressure and temperature are applied to air-formed cellulose blanks, then product forming quality is improved, but structural weaknesses such as cracks and fibre separations increase
Solution Approach 1:
The cellulose blank structure is pre-compressed in specific regions before the forming process to create a differentiated structure. This preliminary compression prepares the blank to better withstand the subsequent high forming pressure and temperature by having strategically placed structural support in residual sections while maintaining formability in product sections, thereby preventing cracks and fibre separations during forming.
Solution Approach 2:
The blank structure has locally differentiated compression properties that prepare different regions for their specific roles during forming. Product sections with lower compression are pre-prepared to be more compliant and resistant to cracking under forming pressure, while residual sections with higher compression provide localized support. This local quality differentiation enables high forming quality without structural failure.
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 method prevents undesired breakage and enhances the forming of cellulose products, especially deep-drawn items, by minimizing structural weaknesses and enabling faster production cycles.
Implementation Method 1
compressing at least a portion of the residual section to a first degree of compression higher than a degree of compression of the one or more product sections
Implementation Method 2
heating the cellulose blank structure to a forming temperature in the range of 100-300° C.
Implementation Method 3
pressing the cellulose blank structure with a forming pressure in the range of 1-100 MPa
Data Source
AI summary
A method for forming cellulose products in a mould system from an air-formed cellulose blank structure, where the forming mould system comprises a first mould part and a second mould part. The method comprises the steps: providing the cellulose blank structure, and defining one or more product sections and a residual section; compressing at least a portion of the residual section to a first degree of compression higher than a degree of compression of the one or more product sections; feeding the cellulose blank structure in a feeding direction to a forming position in the forming mould system, where in the forming position each product section is arranged between a corresponding first mould part and second mould part; forming the cellulose products from the cellulose blank structure between the first mould part and the second mould part by heating the cellulose blank structure and pressing the cellulose blank structure.