Thermoplastic Filler Sheet Structuring for Ultrasonic Welding
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Solution Overview
Problem
Existing methods for joining thermoplastic components, such as ultrasonic welding, face challenges in achieving high-quality welds, particularly in terms of energy distribution and material compatibility, which can lead to inconsistent joint strength and reliability.
Innovation Solution
A method involving the use of a filler sheet with a structuring tool to create a surface with protrusions, which acts as energy directors during welding, allowing for improved energy distribution and enhanced weld quality by localizing heat generation at the interface between components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultrasonic welding is used to join thermoplastic components, then joining speed and productivity are improved, but weld quality consistency and joint strength reliability deteriorate due to poor energy distribution and material compatibility
Solution Approach 1:
The patent applies local quality by creating protrusions (energy directors) at specific locations on the component surface. These protrusions are strategically positioned at the weld interface to concentrate ultrasonic energy locally, ensuring consistent energy distribution and reliable weld quality while maintaining high productivity
Solution Approach 2:
The patent employs preliminary action by pre-forming protrusions on the component surface before the welding process. This surface preparation step ensures that when ultrasonic welding occurs, the energy is immediately concentrated at the correct locations, eliminating energy distribution problems and ensuring consistent weld quality from the start
2Reliability
If energy directors are formed directly in the base material of components, then welding quality is improved, but manufacturing complexity and difficulty increase
Solution Approach 1:
The patent uses an intermediary approach by applying a filler sheet with pre-formed protrusions to the component surface. This filler sheet acts as a mediator that provides the necessary energy directors for welding without requiring complex modification of the base component, thus improving weld quality while keeping manufacturing simple
Solution Approach 2:
The patent applies segmentation by separating the energy director function from the main component structure. The protrusions are created on a separate filler sheet that is then applied to the component, allowing the energy directors to be manufactured independently and simply, while still achieving high welding quality
3Reliability
If a filler sheet is applied to the component surface, then energy distribution and weld quality are improved, but the number of manufacturing steps and process complexity increase
Solution Approach 1:
The patent applies merging by combining the filler sheet application with the surface structuring step. The protrusions are formed on the filler sheet during its application to the component, integrating two functions (filling and energy director creation) into one process step, thereby improving weld quality without significantly increasing process complexity
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 method enhances the welding quality and reliability by providing energy directors on the surface of the filler sheet, which improves energy distribution and compensates for dimensional variations or gaps at the interface, resulting in stronger and more consistent welds.
Implementation Method 1
heat is applied to the filler sheet such that the filler sheet is attached to the first surface of the first component and such that the structuring tool is partially embedded in the filler sheet
Implementation Method 2
The dissipation of ultrasonic energy in the thermoplastic components creates molten thermoplastic material at the interface between the workpieces
Data Source
AI summary
A method for producing a component with a surface that is suitable for plastic welding or adhesive bonding of two parts is provided. As a preparation step prior to joining, a filler sheet comprising a thermoplastic material or adhesive is arranged on a first surface of a first component and a structuring tool is arranged on the filler sheet. Mechanical force is applied to the structuring tool and heat is applied to the filler sheet such that the filler sheet is attached to the first surface of the first component and such that the structuring tool is partially embedded in the filler sheet. The structuring tool is subsequently removed from the filler sheet to produce a plurality of protrusions in the outer surface of the filler sheet. After surface structuring the first and second components are joined using any type of welding technique or joined using of adhesive bonding.