Patterned Sonotrode Contact Lines for Low-Damage Multimaterial Welding
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Solution Overview
Problem
Existing ultrasonic welding methods struggle to create satisfactory welds between workpieces made of different materials, particularly when combining plastics with different melting points, often leading to damage due to high forces or energy application.
Innovation Solution
The use of torsional ultrasonic vibrations with sonotrodes having specific contact line configurations and energy directors with wide contact surfaces, allowing for controlled energy introduction at intersection points, reduces the load on workpieces and enables reliable welding without damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If large forces and high energy are applied during ultrasonic welding to achieve satisfactory weld quality with different materials, then welding strength is improved, but damage to sensitive workpieces occurs
Solution Approach 1:
The patent divides the contact surface into multiple discrete contact lines arranged in a specific pattern. Instead of applying force uniformly across the entire surface, the energy is concentrated at these segmented contact lines, which reduces the overall force required while maintaining effective welding at the critical intersection points with the energy director.
Solution Approach 2:
The patent applies different characteristics to different parts of the contact surface. The contact lines are positioned specifically at intersection points with the energy director where welding is needed, while other areas have minimal or no contact. This localizes the welding action to critical areas only, reducing overall force requirements and preventing damage to sensitive workpiece areas.
2Manufacturing precision
If contact force and welding duration are increased to achieve satisfactory welds with different material pairings, then welding quality is improved, but the aluminum layer in laminate films is destroyed
Solution Approach 1:
The contact surface is segmented into discrete contact lines rather than a continuous contact area. This segmentation allows the welding energy to be concentrated at specific points where it is most needed (at the energy director intersection), while distributing the mechanical force across a pattern that prevents excessive localized stress on the aluminum layer.
Solution Approach 2:
The patent applies partial contact only where necessary for welding effectiveness. By positioning contact lines only at intersection points with the energy director and using a specific geometric arrangement, the patent achieves sufficient welding quality without applying excessive force to the entire contact surface, thereby protecting the aluminum layer from destruction.
3Ease of manufacture
If conventional ultrasonic welding methods are used with standard contact surfaces, then the process is simple, but satisfactory welds cannot be achieved with different materials having different melting points
Solution Approach 1:
The contact surface is divided into multiple discrete contact lines arranged in a specific geometric pattern. This segmentation creates multiple localized welding zones that can effectively handle different material pairings by concentrating energy at critical intersection points with the energy director, enabling satisfactory welds with materials of different melting points.
Solution Approach 2:
The patent transitions from a conventional two-dimensional flat contact surface to a three-dimensional patterned contact surface with contact lines arranged in specific geometric configurations. This dimensional change allows for optimized energy distribution and force application that accommodates different material properties and melting points while maintaining process simplicity.
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 approach allows for effective welding of different materials with reduced risk of damage, achieving strong and reliable welds even with sensitive materials like monofilms and multilayer films, ensuring high bonding rates and minimal material impairment.
Implementation Method 1
Ultrasonic vibrations are introduced into one of the workpieces via a working surface of a sonotrode
Implementation Method 2
Heat is generated based on two different mechanisms. On the one hand, movements introduced into the workpiece by the sonotrode lead to heating within the workpiece(s). On the other hand, friction or movements at the interface between the workpieces also lead to heat generation.
Implementation Method 3
movements introduced into the workpiece by the sonotrode lead to heating within the workpiece(s)
Implementation Method 4
The introduced ultrasonic vibrations create ultrasonic welds that bond the workpieces together
Data Source
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Figure 3
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AI summary
Two workpieces (30, 40) are connected by means of ultrasound. This is achieved by first of all providing a workpiece (30), having at least one energy director (31), and a second workpiece (40). The workpieces are brought into contact with one another in such a way the energy director (31) comes into contact with a first surface (41) of the second workpiece (40). Next, ultrasonic vibrations are introduced into one of the workpieces (40) via a working surface (11) of a sonotrode (10). Use is made of a sonotrode (10) having a contour with contact lines (12) on the working surface (11). The sonotrode (10) is positioned with respect to the first workpiece (30) in such a way that the contact lines (12) run transversely with respect to the energy director (31).