Pressure Control Mechanism for Adhesive Thermal Compression Bonding
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Solution Overview
Problem
Current thermal compression bonding machines face challenges in accurately controlling pressure across the tolerance range of production parts, leading to inconsistent adhesive bonding quality and yield, due to difficulties in controlling the force exerted by pneumatic cylinders and varying geometric tolerances.
Innovation Solution
The use of a combination of springs and pneumatic pistons to achieve precise pressure control during the heating and cooling stages, with springs applying calculated force over the contact area and pistons providing additional controlled force to ensure even pressure distribution, accommodating geometric tolerances and enhancing adhesive bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If pneumatic cylinders are used to apply compression force, then the bonding process can be automated, but the force control becomes inconsistent due to cylinder variability and part tolerance variations
Solution Approach 1:
The patent changes the control parameter from force-based (pneumatic cylinder pressure) to displacement-based (linear actuator position). By precisely controlling the displacement of the linear actuator and using compliant fixtures, the system achieves consistent pressure application despite variations in part geometry, resolving the contradiction between automation and pressure control consistency.
Solution Approach 2:
The patent introduces compliant fixtures as an intermediary element between the linear actuator and the parts. These fixtures act as a mediator that converts precise linear displacement into controlled pressure application, accommodating part tolerance variations while maintaining consistent bonding pressure throughout the automated process.
2Device complexity
If fixed compression force is applied, then the equipment structure is simple, but the pressure distribution becomes uneven across parts with varying geometric tolerances
Solution Approach 1:
The patent transitions from a static fixed-force application system to a dynamic system where the linear actuator can precisely adjust its displacement. This dynamic control allows the system to adapt to varying part geometries and tolerances, achieving uniform pressure distribution across different parts while maintaining relatively simple equipment structure.
Solution Approach 2:
The patent changes the controlled parameter from force magnitude to displacement amount. By controlling how far the linear actuator moves rather than applying a fixed force, the system can achieve uniform pressure distribution across parts with varying geometries, balancing equipment simplicity with manufacturing precision.
3Reliability
If higher pressure is applied to ensure complete bonding, then bonding reliability improves, but cosmetic defects increase due to adhesive squeeze-out
Solution Approach 1:
The patent applies local quality by using compliant fixtures that can locally adapt to the specific geometry of each part. This allows the system to apply appropriate pressure locally at each contact point, ensuring complete bonding coverage while controlling the pressure to prevent excessive adhesive squeeze-out and cosmetic defects.
Solution Approach 2:
The patent changes from force-based pressure control to displacement-based control, which inherently limits the maximum pressure applied. By controlling the linear actuator's displacement rather than applying high force, the system achieves complete bonding reliability while preventing the harmful effect of excessive adhesive squeeze-out.
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 solution enables higher adhesive bonding yield and consistent quality by efficiently and accurately achieving desired pressure distributions, minimizing cosmetic defects and ensuring complete adhesive bonding across the parts' surfaces.
Implementation Method 1
The heating blocks 34 and timers are used to deliver heat for a set duration of time to the stacked parts to achieve a certain peak temperature range.
Implementation Method 2
a cooling station having a cooling block 39 that cools a top fixture 36 is incorporated in the machine 30 to cool the assembled parts after the heating cycle
Data Source
AI summary
Mechanism for controlling pressure during the adhesive thermal compression bonding provides benefits of higher production yield, improved adhesive bonding performance and quality. Springs and pneumatic pistons are utilized to provide improved pressure control during the adhesive thermal compression bonding process. All production parts have certain geometric tolerances and automatically accommodating these tolerances increases production yield by reducing waste of incompletely adhesive bonded parts. The gaps caused by the parts tolerance are closed in a controlled manner using the mechanism and the pressure is controlled for effective adhesive bonding.