Ultrasonic Bonding Protrusion Height Gradient
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Solution Overview
Problem
Conventional ultrasonic bonding techniques often lead to material thinning around outer protrusions, resulting in increased stress concentrations and the risk of crack formation due to shrinkage and external forces, which can cause material breakage.
Innovation Solution
The use of ultrasonic bonding equipment with anvil and horn protrusions of varying heights, where the outer protrusions apply a lesser gripping force than the inner protrusions, reducing material stress and increasing the thickness of the bonded material's outer region, thereby enhancing rupture and fatigue strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If uniform protrusions are used in ultrasonic bonding, then bonding consistency is improved, but material thinning and stress concentration occur at outer regions
Solution Approach 1:
The patent applies local quality by varying the height of protrusions based on their position: inner protrusions have a first height while outer protrusions have a second height that is 0.5 to 0.8 times the first height. This localized differentiation ensures that outer regions experience less gripping force and material thinning, while inner regions maintain strong bonding consistency.
2Strength
If high gripping force is applied uniformly, then bonding strength is improved, but material thinning and crack risk increase
Solution Approach 1:
The patent implements local quality by creating a gradient in gripping force through varied protrusion heights. Inner protrusions apply higher gripping force for strong bonding, while outer protrusions apply reduced gripping force (40-80% of inner force) to prevent material thinning and crack formation at stress-prone outer regions.
3Reliability
If outer protrusions grip tightly, then bonding completeness is improved, but stress concentration and material breakage risk increase
Solution Approach 1:
The patent applies local quality by differentiating protrusion heights to match the varying thickness requirements of different material regions. Outer protrusions with reduced height (0.5-0.8 times inner protrusion height) maintain bonding completeness while preserving outer material thickness, ensuring uniformity within ±0.05mm.
4Device complexity
If uniform protrusion height is used, then device simplicity is maintained, but outer region material stress increases
Solution Approach 1:
The patent implements local quality through a straightforward height differentiation scheme where outer protrusions are simply made 0.5 to 0.8 times the height of inner protrusions. This minimal structural modification effectively reduces material stress at outer regions without significantly complicating the overall device design.
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 reduces crack generation and improves the rupture and fatigue strength of the bonded materials by maintaining a thicker outer region, alleviating stress concentrations from external forces like tensile loads and vibrations.
Implementation Method 1
the horn concurrently applies a back-and-forth linear motion from the supersonic vibration transferred through the horn from a transducer that generates the vibration
Implementation Method 2
the materials undergo solid-state welding from the frictional heat generated by the contact of the two clean material surfaces
Data Source
AI summary
The disclosure is directed to ultrasonic bonding equipment, in which the anvil and horn include protrusions of varying height to grip the material being bonded. The outer protrusions may form smaller or differently shaped indentations in the material to reduce material stresses of the material at the outer region of the material. An exemplary embodiment of an ultrasonic bonding system includes an anvil and a horn arranged facing the anvil to ultrasonically bond a gripped portion of two or more layers of material. The gripped portion of the layers includes an inner region and an outer region. The anvil and the horn apply a gripping force to the outer region that is less than a gripping force applied to the inner region of the gripped materials.