Fabric Joint Strength via Laser Transmission Welding
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Solution Overview
Problem
Existing fabric clothing for paper machines faces challenges in predicting and achieving sufficient tensile strength at joints, particularly in the machine direction, due to unpredictable and strength-reducing effects of ultrasonic and laser welding methods.
Innovation Solution
A fabric clothing with a connection zone using laser transmission welding, where longitudinal ends are connected via absorbent connection elements that absorb laser light, minimizing heat transfer to the woven fabric threads, ensuring strength preservation and easy production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ultrasonic welding is used to connect the two longitudinal ends of the woven fabric strip, then the ends can be joined together, but the strength properties of the welded filaments are reduced and the woven fabric suffers damage
Solution Approach 1:
A connection element made of thermoplastic material serves as an intermediary between the two longitudinal ends of the woven fabric strip. This connection element is welded to both ends using ultrasonic welding, distributing the stress and avoiding direct welding between the fabric ends themselves, thereby preserving the strength properties of the original filaments while achieving a strong joint.
2Ease of manufacture
If laser welding is used to connect the two longitudinal ends of the woven fabric strip, then the connection can be made, but the heat created during welding reduces the strength of the threads if excessively heated
Solution Approach 1:
The connection element made of thermoplastic material acts as a mediator that absorbs the welding energy during laser welding. The laser beam welds the connection element to the fabric ends through melting and fusion, while the connection element's material properties allow it to withstand the thermal process without transmitting excessive heat to the woven fabric threads, thus preserving their strength.
Solution Approach 2:
The invention controls the welding parameters (laser power, welding speed, focal position) to optimize the thermal process. By adjusting these parameters, the welding heat is concentrated in the connection element rather than being transmitted to the woven fabric threads, allowing strong welding while maintaining thread strength.
3Reliability
If the joint is made stronger to ensure sufficient tensile strength, then the connection reliability improves, but the complexity of production increases
Solution Approach 1:
The connection element serves as a simple intermediary component that can be easily attached to both ends of the fabric strip using standard ultrasonic or laser welding equipment. This approach achieves strong, reliable joints without requiring complex production setups, as the connection element simplifies the welding process by providing a dedicated interface between fabric ends.
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 solution provides a predictable and strong connection with maintained thread strength, reducing the complexity of production while ensuring the fabric clothing withstands tensile stresses during operation.
Implementation Method 1
The connection element, in particular the at least one connection element (4), comprises or is composed of a material which absorbs light from a wavelength range between 780 nm and 1100 nm, in particular between 800 nm and 1000 nm
Implementation Method 2
the two longitudinal ends are welded to one another by means of transmission welding, in particular by means of laser transmission welding
Implementation Method 3
The transparent mating partner is then also heated on the surface by way of thermal conduction
Implementation Method 4
The transparent mating partner herein is penetrated by the laser beam without being appreciably heated. The laser beam is absorbed in a surface-proximal layer only in the second mating partner, wherein the laser energy is converted to thermal energy and the plastics material is fused
Data Source
AI summary
A fabric clothing, in particular a press felt, for use in a machine for producing a fibrous web, contains a woven fabric strip having interwoven longitudinal threads and cross threads, as well as having a first and a second longitudinal end. The two longitudinal ends of the woven fabric strip are connected to one another in a connection zone. Provision is made that the two longitudinal ends are welded to one another by a transmission welding, in particular by a laser transmission welding.