Embossing roller, embossing unit, embossing method and embossed product
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Solution Overview
Problem
Current embossing techniques for tissue paper impose high mechanical stress on cellulose fibers, leading to non-uniform deformation and weakening, which results in localized breakage and uneven stress distribution, limiting the flexibility in choosing embossing patterns due to the anisotropic nature of cellulose material.
Innovation Solution
An embossing unit with an embossing roller featuring protuberances that have a variable inclination and stress-related characteristics along their linear extension, allowing for modulation of mechanical stress by adjusting the angle and shape of the protuberances, enabling uniform deformation and weakening of the cellulose ply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional embossing techniques are used with fixed geometry protuberances, then the embossing process can be performed, but non-uniform deformation and stress concentration occur leading to localized breakage of cellulose fibers
Solution Approach 1:
The embossing roller is equipped with protuberances that have variable cross-sectional geometry along their length, with different stress-related characteristics at different positions. This allows each region of the protuberance to apply appropriately tailored stress to the cellulose material, achieving uniform deformation while preventing localized breakage by matching the stress distribution to the material's structural characteristics.
Solution Approach 2:
The invention changes the geometric parameters of the embossing protuberances, specifically varying the cross-sectional shape, size, and orientation along the length of each protuberance. This parameter variation enables modulation of the stress distribution during embossing, transforming the uniform stress application into a graduated stress profile that prevents fiber breakage while maintaining deformation uniformity.
2Adaptability or versatility
If embossing patterns are designed without considering cellulose fiber arrangement, then aesthetic or functional embossing can be achieved, but excessive stress causes non-homogeneous weakening of the cellulose material
Solution Approach 1:
The variable cross-sectional geometry of the protuberances allows the embossing system to adapt to the anisotropic nature of cellulose fiber arrangement. By modifying the stress-related characteristics at different positions along the protuberance length, the system can accommodate various embossing patterns while maintaining homogeneous stress distribution that prevents non-uniform weakening of the material.
3Shape
If current engraving techniques are used to create embossing rollers, then the appearance of embossing pattern is improved, but non-homogeneous elongation occurs leading to wrinkles and slippage
Solution Approach 1:
The invention applies parameter changes to the protuberance geometry, specifically varying the cross-sectional dimensions and shape along the length of each protuberance. This graduated variation in geometric parameters enables the embossing roller to produce the desired pattern appearance while simultaneously controlling the elongation distribution to prevent wrinkles and slippage during the embossing process.
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 allows for uniform deformation and reduced stress concentration on cellulose fibers, improving the embossing process by modulating stress distribution, thereby enhancing the quality and consistency of tissue paper production.
Implementation Method 1
The two rollers are pressed against each other so that the protuberances penetrate the lateral surface of the pressure roller as a result of the compressive deformation of the yielding coating of said pressure roller
Implementation Method 2
the embossing roller is provided with protuberances that penetrate an elastically yielding coating layer provided on the pressure roller
Implementation Method 3
The cellulose material, forming the web material, which passes through the nip formed between the two rollers, is permanently deformed with the formation of embossing protrusions
Data Source
AI summary
The embossing unit includes at least one embossing roller with a rotation axis and a substantially cylindrical surface with a plurality of embossing protuberances with linear extension; a pressure roller with a yielding surface; an embossing nip defined between the pressure roller and the embossing roller; a feed path of a web material extending through the embossing nip. Along the linear extension thereof the embossing protuberances have a variable inclination with respect to the rotation axis of the embossing roller and a variable cross section along the longitudinal extension of the embossing protuberances.