Balanced Twill Forming Fabric Cross-Direction Displacement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing forming fabrics for papermaking face issues with fabric guiding on a paper machine, particularly due to cross-direction displacement caused by twill patterns on the machine side layer contact surface, which affects the integrity and stability of the papermaking process.
Innovation Solution
A forming fabric with a paper side layer and a machine side layer interconnected by pairs of binder weft yarns, arranged in a broken twill pattern with an offset mirror symmetric arrangement, which reverses direction after an equal number of warp knuckles, ensuring stability and minimizing displacement during the papermaking process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional twill pattern is used on the machine side layer, then the fabric has good drape and flexibility, but the fabric displaces in the cross direction during guiding on the paper machine
Solution Approach 1:
The patent applies asymmetry by using a balanced twill weave pattern where the twill runs in opposite directions on alternating sides of the fabric. This creates a symmetric balance that cancels out directional bias, preventing cross-direction displacement while maintaining the drape and flexibility benefits of twill weaving.
Solution Approach 2:
The patent changes the weave parameters by implementing a specific balanced twill pattern with controlled float lengths and interlacing points. By adjusting these weave parameters to create equal but opposite twill directions, the fabric achieves both flexibility and guiding stability.
2Reliability
If the MS layer contact surface has a twill pattern, then the fabric has good forming characteristics, but guiding becomes problematic due to cross-direction displacement
Solution Approach 1:
The balanced twill weave creates opposing asymmetric patterns that cancel each other's directional influence. This allows the fabric to maintain good forming characteristics from the twill structure while eliminating the cross-direction displacement that would otherwise occur during guiding.
Solution Approach 2:
The opposing twill directions act as counterweights to each other, with one side's directional bias being canceled by the other side's opposite bias. This mutual counteraction prevents net displacement in any cross direction while preserving the forming fabric's functional performance.
Data Source
Figure 1~2
Figure 3~5
Figure 6~9
AI summary
A forming fabric for a papermaking machine woven according to a repeating fabric weave pattern is provided. The fabric includes a PS layer having a PS surface, with the PS layer including PS warps and PS wefts interwoven in a first repeating pattern, and a MS layer having a MS surface, with the MS layer including interwoven MS warps and MS wefts. A plurality of pairs of binder weft yarns is provided, with each of the pairs of binder weft yarns comprising first and second binder weft yarns that are interwoven according to a binder weft pattern with the PS warps and the MS warps to bind the PS and MS layers together in the composite forming fabric, and each interchanges between the layers at exchange points. In each pattern repeat of the fabric weave pattern, each of the MS warps forms one or more MS warp knuckles over single ones of the MS wefts, the MS warp knuckles of the MS warps are arranged in a broken twill having an offset mirror symmetric arrangement, and a direction of the broken twill reverses after an equal number of MS warp knuckles.