Ultrasonic Welding Roller Surface With Recesses for High Feed Rates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ultrasonic welding devices face limitations in processing speed and reliability due to insufficient energy transfer at higher feed rates, leading to poor seam quality and thread clamping issues, especially when joining nonwoven materials with additional elastic threads.
Innovation Solution
The processing element features a top surface with a base section and recess sections that allow for the retention of melted material, reducing friction and enabling wider structural elements for improved thread clamping, while the counter-element's concave curvature increases contact time and energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the feed rate is increased to improve processing speed, then productivity increases, but the sonotrode applies insufficient energy to the material for reliable welding
Solution Approach 1:
The sonotrode sealing surface is divided into multiple structural elements (protrusions) distributed across the surface. Each protrusion acts as an independent energy transfer unit, concentrating ultrasonic energy at multiple discrete contact points. This segmentation allows the sonotrode to maintain sufficient energy application even at higher feed rates, as the distributed protrusions ensure continuous material contact and energy transfer throughout the welding zone.
Solution Approach 2:
The invention transitions from a flat, two-dimensional sealing surface to a three-dimensional surface with protrusions having significant height (0.5-2.0 mm). This dimensional change creates multiple contact levels, ensuring that even when material is moved through the gap at higher speeds, the protrusions maintain adequate contact time and energy transfer at each contact point, thereby preserving welding reliability while enabling increased productivity.
2Use of energy by moving object
If the force with which the sonotrode is pressed onto the material is increased to transfer more energy per stroke, then energy transfer improves, but friction increases and melted components are pressed out of the joining zone
Solution Approach 1:
The sealing surface is segmented into multiple discrete protrusions rather than a continuous surface. This segmentation distributes the applied force across multiple contact points, reducing the friction force at each individual protrusion-material interface. Consequently, less total friction is generated, preventing melted components from being pressed out of the joining zone while still achieving sufficient energy transfer for reliable welding.
Solution Approach 2:
The protrusions create localized contact zones with specific geometric characteristics (height, width, spacing) that optimize the balance between energy transfer and friction. The local geometry of each protrusion is designed to concentrate ultrasonic energy effectively while limiting the contact area that generates friction, thereby achieving high energy transfer without excessive frictional forces that would expel melted material.
3Use of energy by moving object
If the vibration amplitude of the ultrasonic vibration is increased to transfer more energy per stroke, then energy transfer improves, but the sonotrode material may be damaged
Solution Approach 1:
The sealing surface is divided into multiple protrusions that distribute the vibrational energy across multiple contact points. This segmentation allows the sonotrode to operate at higher vibration amplitudes without concentrating excessive stress on a single contact area, thereby transferring more energy to the material while preventing damage to the sonotrode material through distributed load bearing.
Solution Approach 2:
The protrusions are designed with specific local geometric properties (height, width, spacing, shape) that optimize the distribution of vibrational stress. This local quality design enables the sonotrode to sustain higher vibration amplitudes by concentrating energy transfer at the protrusion tips while the bulk of the sonotrode material experiences reduced stress, preventing material damage.
4Reliability
If structural elements are made wider to improve thread clamping, then thread fixation improves, but friction with the material increases
Solution Approach 1:
The protrusions are designed with optimized local dimensions and spacing that balance thread clamping capability with friction generation. The width, height, and spacing of each protrusion are specifically tailored to provide sufficient contact area for thread fixation while limiting the total friction-generating surface area, thereby achieving reliable thread clamping without excessive friction that would hinder material processing.
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 design enhances processing speed and seam quality by retaining melted material, improving thread fixation, and reducing friction, resulting in a more reliable and efficient ultrasonic welding process.
Implementation Method 1
Due to the friction induced by the ultrasonic vibration, a point heating occurs at the contact surfaces lying on top of each other
Implementation Method 2
the sonotrode is subjected to ultrasonic vibration. Due to the friction induced by the ultrasonic vibration, a point heating occurs
Implementation Method 3
Due to the friction induced by the ultrasonic vibration, a point heating occurs at the contact surfaces
Implementation Method 4
so that in particular thermoplastic components of the nonwoven fabric are melted. The melted components of the material sections to be joined flow into each other
Data Source
AI summary
The present invention relates to a processing element for processing a material, such as, e.g. a sonotrode or an anvil, having a substantially cylindrical or cylinder-segment-shaped carrier surface which is intended to come into contact with the material during processing, the processing element being provided to be rotated about its longitudinal axis during processing, so that the carrier surface moves in a circumferential direction and rolls on the material to be processed, wherein at least one structural element is arranged on the carrier surface, which structural element protrudes in a radial direction beyond the carrier surface, wherein the structural element has a top surface which is intended to come into contact with the material to be processed. In order to provide a processing element enabling reliable welding at a higher feed rate, it is proposed according to the invention that the top surface comprises a base section and at least one recess section having a smaller distance from the longitudinal axis than the base section, wherein in a sectional view perpendicularly to the longitudinal axis, the base section and the recess section are arranged next to one another.