Ultrasonic Sealing Tool Pattern for Flexible Materials
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Solution Overview
Problem
Existing ultrasonic sealing tools for flexible materials face limitations in bond strength and operating window due to narrow, highly-focused bonding areas, which can damage films and result in leakage or film fracturing, and previous designs with interlocking patterns are difficult to align and stress the film.
Innovation Solution
An ultrasonic sealing device with a horn and anvil featuring a seal pattern of multiple protrusions and recesses with curved edges, forming melt initiation points in two parallel planes, providing a wider seal area and hydraulic resistance to prevent sealant flow, thus enhancing bond strength and reducing film stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single raised bead in the anvil and flat horn design is used, then the seal is leak-free, but the bond strength is limited and the bonding area is extremely narrow
Solution Approach 1:
The patent divides the single concentrated bonding area into multiple discrete bonding locations by adding protrusions at different heights and positions on the anvil surface. This segmentation distributes the bonding process across multiple points, increasing overall bond strength while maintaining the leak-free seal through each individual bonding point.
Solution Approach 2:
The patent creates different bonding characteristics at different locations on the anvil surface by varying the height, shape, and distribution of multiple protrusions. Each protrusion provides a localized bonding zone with optimized properties for its specific position, allowing the seal to achieve both strength and reliability through differentiated local bonding qualities.
2Device complexity
If a single raised bead design is used, then the sealing process is simple, but the process operating window is very narrow and highly sensitive to weld force and duration
Solution Approach 1:
By segmenting the bonding process into multiple protrusions, the patent creates multiple independent bonding zones that collectively provide a broader process window. Variations in weld force or duration at any single location are compensated by the other protrusions, reducing the overall sensitivity to process parameter variations while maintaining simplicity in tool design.
3Area of stationary object
If an interlocking horn and anvil with truncated pyramid pattern is used, then the sealing surface area is greater, but the alignment is critical and difficult to maintain
Solution Approach 1:
The patent replaces the sharp-cornered truncated pyramid pattern with protrusions that have rounded tops and curved surfaces. This curvature eliminates the alignment sensitivity caused by sharp edges and flat surfaces requiring precise matching. The rounded features provide a more forgiving interface that maintains greater sealing surface area while significantly improving alignment ease and reducing the criticality of horn-anvil positioning.
4Quantity of substance
If pyramid shaped pockets with sharp angles are used, then the sealant layer can be accommodated, but the film bursts at peak points from pressure
Solution Approach 1:
The patent eliminates the sharp angle peaks of pyramid-shaped pockets by using protrusions with rounded tops and curved surfaces. This curvature distributes the pressure from forced sealant flow across a broader, more gradual surface, preventing the concentrated stress that causes film bursting at sharp peaks while still providing sufficient volume to accommodate the sealant layer.
Solution Approach 2:
The patent changes the geometric parameters of the bonding features from sharp-angled pyramids to rounded protrusions with controlled radius of curvature. This parameter change modifies the stress distribution during sealant flow, reducing peak stresses that cause film fracturing while maintaining the ability to accommodate the sealant layer through adjusted protrusion dimensions and spacing.
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 competitive ultrasonic seals and 20% stronger than heat seals, with a wider operating window and no film damage, while maintaining an aesthetically pleasing finish.
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 resulting bond is extremely narrow which concerns some end consumers and limits the strength of the bond. The highly-focused bonding area causes almost all of the film's sealant layer to be forced out of the bond area
Data Source
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Figure 2
Figure 3A
AI summary
An ultrasonic sealing device (100), including a horn (112) having a sealing surface, an anvil (114) having a sealing surface, at least one of the horn (112) and the anvil (114) being moveable to engage the respective sealing surfaces, the sealing surfaces of the horn (112) and the anvil (114) including a plurality of protrusions (302) and a recess between each of the protrusions (302), each of the protrusions (302) having a distal surface (322) and sloped sidewalls with curved edges therebetween and each of the recesses including a recess surface (320) with curved edges, wherein, upon engagement of the sealing surface of the horn (112) with the sealing surface of the anvil (114), the distal surfaces (322) of each of the protrusions on each of the sealing surfaces engage corresponding ones of the recess surfaces (320) of each of the recesses on each of the sealing surfaces and define gaps (330) between the sidewalls of each adjacent protrusion.