Plastic Joint Surface Structure for Demolding and Weld Strength
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Solution Overview
Problem
Existing plastic molding techniques face challenges in demoldability and joint strength between plastic components, particularly when complex shapes with projections are involved, leading to adhesion issues and increased costs due to the need for mold release agents.
Innovation Solution
The design incorporates a first component with a contact surface featuring protruding portions and recesses on its outer side surfaces, allowing for improved demoldability and increased joint strength through efficient vibration welding, while reducing the amount of plastic required by strategically placing recesses to prevent adhesion to the mold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the first component has projections such as bosses or ribs on the outer surface, then the structural complexity and joint strength are improved, but the demoldability deteriorates due to adhesion to the movable die
Solution Approach 1:
The patent divides the outer surface of the first component into multiple regions: a general portion and multiple protruding portions. The protruding portions are strategically positioned to prevent contact between the movable die and critical structural features during demolding, thereby segmenting the interaction zones between mold and component.
Solution Approach 2:
The patent applies local quality by creating distinct surface regions with different functions. The general portion maintains normal molding contact, while the protruding portions specifically prevent adhesion in critical areas. This localized differentiation allows the component to maintain structural integrity while improving demoldability.
2Ease of manufacture
If a mold release agent is applied to improve demoldability, then the ease of manufacture is improved, but the manufacturing cost increases
Solution Approach 1:
The patent implements self-service by designing the first component's geometry to inherently prevent adhesion during demolding. The protruding portions automatically create separation zones between the movable die and the component surface, eliminating the need for external mold release agents and reducing manufacturing costs.
3Strength
If the first component and second component are joined by vibration welding, then the joint strength is improved, but the amount of plastic required increases
Solution Approach 1:
The patent optimizes the geometric parameters of the protruding portions, including their height, width, and positioning relative to the joint surface. By carefully controlling these parameters, the design achieves effective adhesion prevention while minimizing the volume of plastic material required, thus reducing overall component weight and material consumption.
Data Source
AI summary
A plastic product includes a first component made of plastic and a second component made of plastic. The first component includes a first joint surface. The second component includes a second joint surface joined to the first joint surface. The first component includes a contact surface that is located on a side opposite to the first joint surface in a facing direction. The contact surface includes a general portion and a protruding portion. The first component includes at least one recess in an outer side surface located between the first joint surface and the contact surface in a part in which the protruding portion is provided. The recess opens in the outer side surface.