FEP Clamping Tool for 2-Micron Laser Welding of Irregular Thermoplastics
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Solution Overview
Problem
Current laser welding processes for thermoplastic materials with complex or irregular surfaces are challenging due to the unsuitability of materials used for clamping tools when transitioning to 2-micron laser wavelengths, as most plastics absorb this radiation, causing the clamping tools to melt and preventing effective force transfer.
Innovation Solution
The use of fluorinated ethylene propylene (FEP) as a clamping tool material, which has low power losses when transmitting 2-micron laser radiation and can be machined to conform to complex shapes, allowing for effective clamping and welding of thermoplastic parts without absorbing significant laser energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional plastic materials are used for clamping tools in 2-micron laser welding, then the clamping force can be effectively transferred to the workpieces, but the clamping tools will melt under the laser beam due to high laser radiation absorption
Solution Approach 1:
The patent changes the material parameter of the clamping tool from conventional plastics to fluorinated ethylene propylene (FEP), which has fundamentally different laser radiation absorption characteristics at 2-micron wavelength. This material substitution allows the clamping tool to transmit laser radiation with minimal absorption while maintaining mechanical clamping functionality, resolving the contradiction between force transfer and laser resistance.
2Loss of energy
If glass is used as clamping tool material for 2-micron laser welding, then laser radiation transmission is achieved, but the ability to conform to complex or irregular workpiece surfaces is lost
Solution Approach 1:
The patent changes the material from glass to FEP fluoropolymer, which combines the laser transmission properties needed for 2-micron wavelengths with the machinability required to create complex surface geometries. This allows the clamping tool to be manufactured with custom contours that match irregular workpiece surfaces while maintaining low laser power loss.
3Ease of manufacture
If 1-micron laser wavelength is used for welding, then conventional clamping materials can be used, but laser sensitive additives are required in the thermoplastic materials
Solution Approach 1:
Instead of using 1-micron lasers that require laser-sensitive additives (carbon black) in the thermoplastic materials, the patent inverts the approach by using 2-micron lasers that work with unfilled plastics. This eliminates the need for additives in the workpieces, though it requires specialized FEP clamping tools, thereby simplifying the joint design while changing the clamping tool material.
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
FEP clamping tools enable efficient laser welding of thermoplastic parts with complex surfaces by maintaining clamping force and minimizing laser radiation absorption, facilitating uniform melting and solidification of the workpieces, even with non-flat surfaces.
Implementation Method 1
FEP clamping tools enable efficient laser welding of thermoplastic parts with complex surfaces by maintaining clamping force and minimizing laser radiation absorption
Implementation Method 2
laser radiation is directed onto the workpieces through a clamping tool to melt the irradiated portion of the workpieces
Implementation Method 3
Laser welding is based on the same basic requirements of material compatibility as other welding techniques, but is often found to be more forgiving of resin chemistry or melt temperature differences than most other plastic welding processes
Implementation Method 4
clamping the thermoplastic workpieces between a pair of clamping tools, at least one of which is made of a plastic material that has substantially the same power loss as borosilicate glass when transmitting laser radiation
Implementation Method 5
The laser radiation is then turned off and the workpieces are allowed to solidify before releasing them from the clamping tools
Data Source
AI summary
A laser welding system for joining first and second thermoplastic workpieces, and including a clamp, an actuator, and a laser source. The clamp includes first and second clamping structures positioned together to engage opposite sides of the workpieces when they adjoin each other. The first clamping structure has a non-flat or irregular surface, facing the first workpiece. The actuator causes the clamping structures to press the first and second workpieces together. The laser source applies laser radiation having a wavelength of 2 microns toward the workpieces to be joined, while they are pressed together by the clamp, to melt irradiated portions of the workpieces to one another. The first clamping structure transmits substantially all of the energy of the laser radiation through the material. The first workpiece has a non-flat or irregular surface facing the first clamping structure, which substantially conforms with the surface of the first clamping structure.