Thermal Adhesive Sheet Bonding via Steam Conduction
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Solution Overview
Problem
Conventional methods for bonding thermal adhesive sheets to workpieces with complex surfaces, such as those with undercut or recess portions, fail to adequately heat and bond these areas due to the shape of the workpiece, leading to incomplete bonding and potential overheating of directly facing surfaces.
Innovation Solution
A sheet bonding method and apparatus that uses a combination of vacuum pressure and steam supply to heat the adhesive layer of the thermal adhesive sheet, ensuring uniform heating and bonding to the workpiece surface, including hard-to-reach areas like inner faces and side faces of cutouts, by conducting heat from steam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heater is positioned around the workpiece to heat the thermal adhesive sheet, then the upper face and surrounding side faces can be sufficiently heated, but the inner face of cutout portions and lower face cannot be sufficiently heated
Solution Approach 1:
The patent introduces steam as an intermediary heating medium. Instead of directly positioning heaters around the workpiece, steam is supplied to a heating chamber where it heats the adhesive sheet indirectly. The steam condenses on the adhesive sheet, transferring heat efficiently to all surfaces including inner faces of cutouts and lower faces that would be inaccessible to direct heaters.
Solution Approach 2:
The patent uses steam (a fluid) to achieve heating. By supplying steam to the heating chamber, the system utilizes fluid dynamics and phase change (condensation) to distribute heat uniformly across all surfaces of the adhesive sheet, including complex geometries that solid heaters cannot reach.
2Temperature
If the temperature of the heater is raised or heating time is increased to heat distant surfaces, then those surfaces can be heated, but the directly facing surfaces will be overheated
Solution Approach 1:
The patent changes the heating parameter from direct contact heating to steam condensation heating. This parameter change allows for uniform temperature distribution because steam condenses at a constant temperature (100°C at atmospheric pressure), providing a self-regulating heating mechanism that prevents local overheating while ensuring adequate heating of all surfaces.
Solution Approach 2:
The patent utilizes the phase transition of steam condensing into water. During condensation, steam releases latent heat uniformly across the adhesive sheet surface. This phase change process provides consistent heat transfer that prevents overheating of directly facing surfaces while adequately heating distant surfaces like inner faces and lower faces.
3Force
If a rubber member is used to press the thermal adhesive sheet against the workpiece, then bonding pressure is applied, but undercut portions and recess portions cannot be contacted
Solution Approach 1:
The patent replaces the mechanical rubber member pressing system with a vacuum suction system. By applying vacuum to the heating chamber, the adhesive sheet is suctioned onto the workpiece surface. This substitution allows the sheet to conform to complex surfaces including undercut and recess portions, as the vacuum force acts uniformly across the entire sheet surface rather than relying on mechanical contact.
Solution Approach 2:
The patent utilizes vacuum pressure (pressure differential) to achieve bonding. By creating a vacuum environment in the heating chamber, atmospheric pressure pushes the adhesive sheet against the workpiece surface. This pressure differential method allows the sheet to adapt to any surface contour, including complex geometries that rigid or elastic mechanical pressers cannot accommodate.
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 uniform and effective bonding of thermal adhesive sheets to complex workpiece surfaces, preventing overheating and ensuring complete transfer of the adhesive layer, even to areas distant from the heater, thereby improving the reliability of the bonding process.
Implementation Method 1
supplying steam to a space around the workpiece so as to heat the adhesive layer by conduction of heat from the steam
Implementation Method 2
a vacuum section that draws a vacuum in a space inside the lower chamber member partitioned off by the thermal adhesive sheet
Data Source
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AI summary
A sheet bonding method includes a closely attaching step and a steam supply step. In the closely attaching step, a thermal adhesive sheet (F) is closely attached to the surface of a workpiece (W) to closely attach an adhesive layer of the sheet to the surface of the workpiece (W). In the steam supply step, steam is supplied to the space around the workpiece so as to heat the adhesive layer by heat conduction from the steam to bond the thermal adhesive sheet (F) to the workpiece (W).