Plastic Component Welding With Grooved Fastening Areas
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Solution Overview
Problem
Existing methods for attaching ultrasonic sensor mounts to vehicle bumpers using ultrasonic welding can impair the visual appearance due to energy input on the visible side, and there is a need for a manufacturing process that ensures a high-strength bond without compromising aesthetics.
Innovation Solution
A method involving injection molding of plastic components with closely spaced grooves or pyramids in the fastening area, followed by ultrasonic welding with a sonotrode, where each subsequent welding step occurs in an area already stressed and relaxed by the previous step, using a structured surface to enhance bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If ultrasonic welding is performed on smooth contact surfaces to maximize contact area, then welding coverage is improved, but visible energy input impairs visual appearance
Solution Approach 1:
The invention applies different surface qualities to different areas: the visible outer surface remains smooth for aesthetic purposes, while the fastening area features a groove structure that enhances ultrasonic welding. This local differentiation allows the contact area to be effectively increased through the groove structure without compromising the visual appearance of the visible surfaces.
2Strength
If high energy input is used for ultrasonic welding to ensure connection strength, then connection strength is improved, but visible traces of welding increase
Solution Approach 1:
The groove structure concentrates the ultrasonic energy input locally within the fastening area, allowing effective welding with reduced overall energy input. The grooves guide the sonotrode pins to create strong connections while limiting the visible impact to only the non-aesthetic fastening area, thus maintaining visual appearance while ensuring connection strength.
3Strength
If step-by-step welding is performed in stressed and relaxed areas, then connection strength increases by 9-13%, but process complexity increases
Solution Approach 1:
The welding process is divided into multiple sequential steps that follow a specific path through the fastening area. The sonotrode moves systematically through different zones, creating a pattern of stressed and relaxed areas that enhances connection strength. This segmentation of the welding process into controlled steps achieves superior mechanical properties while maintaining manageable process complexity through systematic execution.
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 achieves a 9-13% increase in joint strength and maintains a flawless visual finish by minimizing energy and heat input, ensuring a robust connection between plastic components.
Implementation Method 1
the energy for welding being introduced into the plastic components via at least two pins of the sonotrode
Implementation Method 2
By melting or liquefying the plastic material of the second component, an intimate connection or interlocking of the plastic of the second component with the surface structure of the first component takes place
Data Source
Figure 1
Figure 2~3
Figure 4~5c
AI summary
The invention relates to a method for producing a connection between a first component (31) made of plastic and a second component (32) made of plastic, wherein at least one of the two components is produced by injection molding, and wherein at least one fastening area (20) is provided on the at least one component (31, 32) which is injection molded with a surface structure of grooves (21) of small spacing, and wherein the components (31, 32) are joined together in the fastening area (20) in an ultrasonic welding process.