Ultrasonic Welding Anvil Decoupling for Bag Sealing
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Solution Overview
Problem
Existing devices for producing tubular bags with overlap seams face issues with unsatisfactory welding results due to resonance vibrations in the filling tube, leading to inconsistent gap widths and noise, making it difficult to achieve a constant and controllable welding process.
Innovation Solution
A device with a separate, solid anvil that guides the longitudinal edges of the bag blank, combined with a filling tube that can be independently adapted, decoupled from the ultrasonic vibrator, and a sonotrode that ensures precise alignment and welding, minimizing vibrations and noise, and allowing for adjustable welding force and gap control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the filling tube is used as an anvil for ultrasonic welding, then the device structure is simplified, but resonance vibrations occur leading to poor welding results
Solution Approach 1:
The device is divided into functionally independent components: the filling tube for filling operations and the anvil for welding operations. This segmentation allows each component to be optimized for its specific function without interfering with the other, resolving the contradiction between structural simplicity and welding precision.
Solution Approach 2:
The anvil function is extracted from the filling tube by introducing a separate, dedicated anvil component. This extraction eliminates the resonance vibrations that occurred when the filling tube served as the anvil, while maintaining overall device simplicity through modular design.
2Device complexity
If the filling tube serves as the anvil, then fewer components are needed, but vibrations cause inconsistent gap widths
Solution Approach 1:
By segmenting the device into separate filling tube and anvil components, the system achieves both functional independence and precision control. The anvil can be specifically designed with rigid properties and precise geometric features to maintain consistent gap widths during welding.
Solution Approach 2:
The anvil is designed with specific local properties (rigidity, geometric precision) that are optimized for welding operations, while the filling tube maintains its own optimized properties for filling operations. This local optimization resolves the contradiction between component count and precision.
3Device complexity
If the filling tube is used as anvil, then the device is simpler, but noise increases due to resonance
Solution Approach 1:
The anvil function is extracted from the filling tube, allowing the filling tube to be decoupled from the ultrasonic vibration system. This extraction eliminates the resonance vibrations that generated noise, while the separate anvil absorbs and dissipates vibration energy locally.
Solution Approach 2:
The separate anvil acts as an intermediary between the ultrasonic vibrator and the filling tube, absorbing vibration energy and preventing it from being transmitted to the filling tube and subsequent filling operations, thereby reducing noise.
4Adaptability or versatility
If the filling tube is made elastic with thin walls for optimal filling, then filling performance improves, but it cannot serve as a rigid anvil
Solution Approach 1:
By segmenting the device into separate filling tube and anvil components, the system allows the filling tube to be optimized for filling (elastic, thin-walled) while the anvil is optimized for welding (rigid, stable). This segmentation resolves the contradiction between filling adaptability and anvil rigidity.
Solution Approach 2:
Different components are assigned different local qualities: the filling tube has elastic properties for adaptability, while the anvil has rigid properties for stable welding. This local optimization allows each component to perform its function optimally without compromise.
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 achieves high-quality, reproducible ultrasonic seams with reduced noise and vibrations, ensuring consistent welding results and efficient material usage, as the anvil and sonotrode are decoupled from the filling tube, allowing for optimal control over the welding process.
Implementation Method 1
welding the longitudinal edges or edges of a bag blank to form a longitudinal seam of a flexible bag by means of ultrasound
Data Source
Figure 1
Figure 2~5
AI summary
The device (12) has a sonotrode (26), an anvil (22), and a filling tube (14) that is supported separately on a longitudinal welding device for filling an open bag. The anvil has guiding sections for longitudinal edges of a bag section, where the guiding sections are connected with each other. The guiding sections are designed as overlapping grooves that are arranged parallel to each other. The grooves converge in sections in a transportation direction (18) of the bag section. The tube has a section (20) running in a longitudinal direction and engages the anvil in the section.