Ultrasonic Sealing Tool Pattern for Flexible Materials
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Solution Overview
Problem
Existing ultrasonic sealing tools for flexible materials, such as pouches, face limitations in bond strength and operating window due to narrow, highly-focused bonding areas, which can lead to film damage and fracturing, and require precise alignment, making them difficult to maintain and prone to stress.
Innovation Solution
The design features a horn and anvil with a wavy seal pattern comprising multiple protrusions and recesses with flat distal surfaces and sloped sidewalls, creating a multi-plane seal that accommodates molten sealant flow and reduces stress on the film, with specific dimensions and spacings to enhance bond strength and operating window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single raised bead in the anvil and flat horn design is used, then the sealing process is simple and effective, but the bond area is extremely narrow and the process operating window is very narrow
Solution Approach 1:
The sealing surface is segmented into multiple protrusions (peaks) and recesses (valleys) arranged in a wave pattern, transforming a single concentrated bonding point into multiple distributed bonding areas. This segmentation increases the total bond area while maintaining the simplicity of the tool design.
Solution Approach 2:
The sealing pattern extends from a single-point contact in one dimension to a multi-point contact pattern across two dimensions. The wave pattern creates peaks and valleys that distribute the bonding area across the sealing surface, effectively increasing the bond area without significantly increasing device complexity.
2Device complexity
If a single raised bead design is used, then the tool design is simple, but the bond strength is limited and film damage occurs
Solution Approach 1:
The bonding function is segmented across multiple peaks and valleys rather than concentrated at a single point. This distribution of bonding forces across multiple locations increases overall bond strength while reducing the stress concentration that causes film damage.
Solution Approach 2:
Each peak and valley in the wave pattern provides localized bonding zones with optimized geometry. The protrusions and recesses are designed with specific dimensions and spacing to create optimal local bonding conditions, improving overall bond strength while maintaining simple tool design.
3Quantity of substance
If pyramid shaped pockets are used to accommodate sealant layer, then sealant flow is accommodated, but film fracturing occurs at sharp angles
Solution Approach 1:
The pyramid-shaped pockets with sharp angles are replaced by wave-patterned peaks and valleys with curved, rounded profiles. This curvature eliminates stress concentration points that cause film fracturing while still providing sufficient volume to accommodate the sealant layer during the sealing process.
Solution Approach 2:
The geometry parameters of the sealant accommodation features are changed from sharp-angled pyramids to curved wave profiles. This parameter change maintains the volume necessary for sealant flow while eliminating the harmful sharp corners that cause film failure.
4Measurement precision
If tools interlock with a few thousandths of engagement, then alignment is achieved, but alignment is critical and difficult to maintain
Solution Approach 1:
The interlocking interface is segmented into multiple corresponding peaks and valleys on the horn and anvil surfaces. This segmentation provides multiple alignment points that work together to self-align the tools, reducing the criticality of precise alignment and making it easier to maintain proper positioning during operation.
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 a 40% stronger bond compared to traditional ultrasonic seals and 20% stronger than heat seals, with improved film handling and reduced stress, while maintaining a wide operating window and preventing sealant evacuation, resulting in a more secure and durable seal.
Implementation Method 1
Ultrasonic sealing or welding is a process that generates frictional heat to bond thermoplastic materials together
Implementation Method 2
Ultrasonic sealing or welding is a process that generates frictional heat to bond thermoplastic materials together
Implementation Method 3
the flat distal surfaces of each of the protrusions on each of the sealing surfaces engage corresponding ones of the flat recess surfaces of each of the recesses on each of the sealing surfaces and define gaps between the sloped sidewalls of each adjacent protrusion
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
An ultrasonic sealing device, including a horn having a sealing surface, an anvil having a sealing surface, at least one of the horn and the anvil being moveable to engage the respective sealing surfaces, the sealing surfaces of the horn and the anvil including a plurality of protrusions and a recess between each of the protrusions, each of the protrusions having a flat distal surface and sloped sidewalls with curved edges therebetween and each of the recesses including a flat recess surface with curved edges, wherein, upon engagement of the sealing surface of the horn with the sealing surface of the anvil, the flat distal surfaces of each of the protrusions on each of the sealing surfaces engage corresponding ones of the flat recess surfaces of each of the recesses on each of the sealing surfaces and define gaps between the sloped sidewalls of each adjacent protrusion.