Papermaking felt and method for manufacturing the same
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Solution Overview
Problem
Existing papermaking felts manufactured by overlapping end regions suffer from poor smoothness, particularly at the welded portions, which can result in visible marks and inadequate compressibility, affecting the quality of the papermaking process.
Innovation Solution
The papermaking felt is designed with a configuration where the thickness of the welded portion is adjusted to be between 50% and 95% of the non-welded portion's thickness, ensuring equal thickness under pressure, achieved by overlapping and welding MD-direction and CD-direction end regions without removing yarn materials, and using thermoplastic resin with specific heat-resistant properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If end regions of base fabric are overlapped and welded to form endless papermaking felt, then productivity is improved and manufacturing efficiency is increased, but the welded portion has poor compressibility and generates visible marks on the felt surface
Solution Approach 1:
The patent applies parameter changes by controlling the welding conditions (temperature, pressure, time) to achieve a welded portion thickness that is 50-95% of the non-welded portion thickness. This parameter optimization ensures that the welded portion has comparable compressibility to the non-welded portion, eliminating visible marks while maintaining manufacturing efficiency.
Solution Approach 2:
The patent applies local quality by creating a welded portion with specifically controlled local thickness (50-95% of non-welded portion) and local density. This localized property adjustment ensures that the welded portion maintains compressibility similar to the non-welded portion, preventing mark formation while preserving the overall structure of the felt.
2Manufacturing precision
If yarn materials are removed from overlapped portion to reduce welded thickness, then smoothness is improved, but manufacturing complexity increases and productivity decreases
Solution Approach 1:
Instead of removing yarns to reduce thickness (conventional approach), the patent inverts the approach by controlling the welding process itself to achieve the desired thickness reduction. The welding parameters are optimized so that the welded portion naturally attains 50-95% of the original thickness without any yarn removal, simplifying the manufacturing process.
Solution Approach 2:
The patent replaces the mechanical yarn removal system with a thermal-welding control system. By precisely controlling welding temperature, pressure, and time, the welded portion thickness is directly controlled during the welding process itself, eliminating the need for separate yarn removal operations and associated complexity.
3Manufacturing precision
If welded portion thickness is reduced to match non-welded portion under pressure, then compressibility is improved and marks are eliminated, but welding process complexity increases
Solution Approach 1:
The patent applies parameter changes by establishing specific welding parameter ranges (temperature: 100-200°C, pressure: 0.1-10 MPa, time: 1-60 seconds) that directly control the welded portion thickness to be 50-95% of the non-welded portion. These parameter specifications simplify process control while achieving the desired compressibility match.
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 configuration enhances the smoothness of the papermaking felt by eliminating welded portion marks and improving compressibility, leading to better paper quality and efficient manufacturing without the need for yarn removal steps.
Implementation Method 1
at least one of the MD-direction end regions and the CD-direction end regions are overlapped with each other and the overlapped portion is welded
Implementation Method 2
said overlapped portion is welded without removing a part or all of the MD yarn material or the CD yarn material in said overlapped portion
Data Source
AI summary
A papermaking felt includes at least one base fabric composed of a MD yam material in the felt running direction (MD) and a CD yarn material in the felt crossing direction (CD) and having MD end regions and CD end regions, at least one of the MD end regions and the CD end regions are overlapped with each other, the entire overlapped portion is welded without removing a part or all of the MD yarn material or the CD yarn material in the overlapped portion, and when the average thickness of the welded portion of each base fabric is x (mm) and the average thickness of the material portion of each base fabric is y (mm), the relationship between x and y of the at least one base fabric satisfies the following formula (1):0.5≤x/y≤0.95.