Asymmetric Embossing Roller Teeth for Foil Folding
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Solution Overview
Problem
Existing devices for satinizing and embossing packaging foils face challenges in achieving better folding behavior and reducing the memory effect of paper fibers, particularly when the distance between teeth is reduced below 0.3 mm, leading to potential slippage and impaired processing.
Innovation Solution
The device features embossing rollers with pyramidal teeth having a rectangular base, where the opening angle between radially aligned tooth flanks is smaller than between axially aligned flanks, and the tooth height in the radial direction is greater than in the axial direction, allowing for a reduced minimum distance between teeth without compromising force transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the distance between individual teeth is reduced below 0.3 mm to improve satinizing effect and folding properties, then the folding behavior and appearance quality are improved, but slippage occurs between teeth and rollers leading to impaired processing
Solution Approach 1:
The patent applies asymmetry by giving the pyramidal teeth different dimensions in radial and axial directions. The tooth height in radial direction exceeds that in axial direction, and the opening angle radially is smaller than axially. This asymmetric design allows reduced tooth distance (0.05-0.2 mm) for improved satinizing while maintaining sufficient radial tooth height for reliable force transmission and preventing slippage.
Solution Approach 2:
The patent changes the geometric parameters of the teeth by specifying that tooth height in radial direction is greater than in axial direction, and opening angle radially is smaller than axially. These parameter modifications enable the teeth to maintain effective engagement and force transmission capability even at reduced distances below 0.3 mm, resolving the contradiction between precision and reliability.
2Manufacturing precision
If the tooth distance is reduced to achieve better fiber breaking and folding properties, then the paper fiber treatment is improved, but the mechanical driving capability of the teeth is compromised
Solution Approach 1:
The asymmetric tooth geometry with greater radial height than axial height enables the teeth to maintain sufficient driving force capability at reduced distances. The larger radial dimension ensures adequate force transmission for driving the second embossing roller, while the reduced overall distance improves fiber breaking quality and folding properties.
Solution Approach 2:
The patent applies local quality by optimizing different dimensions of the teeth for different functions: the radial dimension is optimized for force transmission and driving capability, while the axial dimension and overall distance are optimized for satinizing effect and fiber breaking. This localized optimization resolves the contradiction between driving force and fiber treatment quality.
3Ease of manufacture
If conventional pyramidal teeth with equal opening angles are used, then the manufacturing is simplified, but the folding properties and satinizing effect are insufficient
Solution Approach 1:
While maintaining the simple pyramidal overall shape for ease of manufacture, the patent introduces asymmetry by specifying different opening angles radially and axially, and different tooth heights in these directions. This controlled asymmetry improves folding properties and satinizing effect without significantly complicating the manufacturing process, as it still involves basic pyramidal geometry with modified dimensions.
Data Source
AI summary
The device for satinizing and embossing packaging foils comprises at least two embossing rollers that are each provided with a toothing consisting of individual teeth, the pyramidal teeth having an essentially rectangular horizontal projection, and the sides of the teeth being essentially parallel and perpendicular, respectively, to the longitudinal axis of the embossing roller. In contrast to the prior art, the opening angle (α) between the radially aligned adjacent tooth flanks is smaller than the opening angle (β) between the axially aligned adjacent tooth flanks, and the tooth height in the radial direction, measured from the tooth tip to the tooth bottom, is greater than the tooth height in the axial direction measured from the tooth tip to the tooth bottom. This dimensioning and arrangement of the teeth provides an improved gearing with a reduced specific pressure as well as an improved processing of the paper part of the foil that results in its better folding, curling, and tubing behavior.