Thermoplastic Sheet Welding via Differential Surface Heating
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Solution Overview
Problem
Conventional welding techniques for thermoplastic sheets, particularly high-frequency dielectric welding, fail to effectively weld materials like PTFE and cause overheating and degradation of outer surfaces in roller shades, altering their technical and aesthetic properties.
Innovation Solution
A method where the main sheet is heated to a temperature below its critical temperature to prevent degradation, while the additional sheet is heated above its melting temperature to facilitate welding, using independent heat transfer means and compression to control the welding process, ensuring the technical and aesthetic properties of the outer surfaces remain unchanged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-frequency dielectric welding is used to weld thermoplastic sheets, then welding speed is improved, but it cannot effectively weld materials like PTFE and causes overheating and degradation of outer surfaces
Solution Approach 1:
The patent applies different heating temperatures to different sheets: the main sheet is heated to a lower temperature (below critical temperature) to prevent degradation, while the additional sheet is heated to a higher temperature (above melting temperature) to ensure proper welding. This local differentiation of heating conditions resolves the contradiction between welding effectiveness and material degradation.
2Manufacturing precision
If heat welding is applied to a single outer surface to reach melting temperature in contact area, then welding is achieved, but the outer surface overheats and degrades
Solution Approach 1:
The patent heats the main sheet to a temperature below its critical temperature, preventing surface degradation, while heating the additional sheet to a temperature above its melting temperature, ensuring proper welding. This localized temperature differentiation resolves the contradiction between achieving welding quality and preventing surface degradation.
3Manufacturing precision
If heat source acts on single outer surface, then melting temperature is reached in contact area, but welding process consumes excessive time
Solution Approach 1:
The patent changes the temperature parameter for heating different sheets: the main sheet is heated to a lower temperature (below critical temperature) while the additional sheet is heated to a higher temperature (above melting temperature). This parameter differentiation enables efficient welding without excessive heating time.
4Manufacturing precision
If heat source is applied to two outer surfaces to reach melting temperature, then welding is achieved, but technical and aesthetic characteristics of outer surfaces are altered
Solution Approach 1:
The patent applies different heating temperatures to different sheets: the main sheet is heated to a lower temperature (below critical temperature) to preserve its surface properties, while the additional sheet is heated to a higher temperature (above melting temperature) to ensure proper welding. This local temperature differentiation resolves the contradiction between welding quality and surface property preservation.
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 method allows for efficient welding of thermoplastic sheets without degrading the outer surfaces, maintaining their mechanical, physical, and aesthetic properties, and is applicable to various applications including roller shades, awnings, and parasols.
Implementation Method 1
the main sheet outer surface is heated to a temperature comprised within the temperature range that is higher than ambient temperature and less than or equal to the main sheet critical temperature
Implementation Method 2
the outer surface of the additional sheet is heated to a temperature that is higher than the heating temperature of the main sheet outer surface, preferably higher than the main sheet critical temperature, and suitable for melting the material of the contact area
Implementation Method 3
with or without applying pressure between them, such that the heating leads to the melting of said thermoplastic material and accordingly to the overlapping of the sheets
Implementation Method 4
the heating leads to the melting of said thermoplastic material and accordingly to the overlapping of the sheets
Data Source
Figure 1~2
Figure 3~4b
Figure 5
AI summary
The present invention relates to a method and apparatus for forming overlaps by welding a main sheet 2 and an additional sheet 5. The welding takes place by heating the contact area, which is made of a thermoplastic material, to a melting temperature, and it is based on performing differentiated heating on each of the outer surfaces 4,7 of the sheets 2,5.