Laser Welding Mobile Polymer Microfluidic Chip Membrane
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Solution Overview
Problem
Existing methods fail to achieve firm and uniform welding between the substrate and membrane of membrane mobile polymer microfluidic chips due to rugged substrate surfaces and deformation issues during the welding process, leading to incomplete or weak bonds.
Innovation Solution
A welding method where the substrate is fixed, and the membrane is pressed against it under controlled pressure, with a pulling force applied to tense the membrane, and a mask is used to shield non-welding areas, ensuring the laser irradiates only the welding area through a transparent path, while air pressure from a stratochamber compensates for substrate irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat plate is used as the upper clamping plate to apply pressure, then the pressure application is simple, but the rugged substrate surface creates clearance and gas film preventing effective welding
Solution Approach 1:
A transparent elastic pad is introduced as an intermediary between the flat clamping plate and the rugged substrate surface. This elastic pad deforms to conform to the substrate's irregularities, eliminating clearance and gas films while maintaining simplicity of the clamping system. The pad acts as a mediator that transfers pressure uniformly across the welding interface despite surface roughness.
Solution Approach 2:
The elastic pad's material properties (elasticity, thickness) are optimized to provide sufficient deformation capability. By controlling the pad's elastic modulus and thickness parameters, the system achieves both good contact with the rugged substrate and adequate laser transmission for welding.
2Manufacturing precision
If the transparent elastic pad is thickened and hardened to ensure large elastic deformation, then the deformation compensation is improved, but the pad absorbs laser energy and affects welding
Solution Approach 1:
The elastic pad's thickness and material hardness are precisely controlled within optimal ranges. The thickness is sufficient to provide the necessary elastic deformation for surface compensation but thin enough to minimize laser energy absorption. The material's elastic modulus is selected to balance deformation capability and optical transparency.
Solution Approach 2:
The pad's properties are optimized locally for the welding region. The material composition and thickness may vary across the pad to provide appropriate elasticity where needed while maintaining high laser transmission in the welding area.
3Manufacturing precision
If higher pressure is applied to the membrane during welding, then the contact between membrane and substrate is improved, but the membrane experiences excessive tensile force and deformation at groove edges
Solution Approach 1:
The elastic pad provides localized pressure distribution that adapts to the substrate's topography. It delivers higher pressure to depressed areas to ensure contact while naturally reducing pressure at raised groove edges, preventing excessive tensile forces on the membrane.
Solution Approach 2:
The elastic pad acts as a cushioning element that prevents direct transmission of excessive point loads to the membrane. By absorbing and distributing pressure before it reaches the membrane-substrate interface, it protects the membrane from damage at vulnerable locations like groove edges.
4Manufacturing precision
If the membrane is tensed up with pulling force to ensure flatness, then the welding flatness is improved, but the membrane deformation control becomes complex
Solution Approach 1:
The pulling force applied to the membrane is precisely controlled within an optimal range. This controlled tension provides sufficient flatness for welding while avoiding excessive tension that would cause deformation or damage. The force parameter is optimized based on membrane properties and welding requirements.
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 ensures a firm, flat, and uniform weld, allowing the microfluidic chip's moving parts and valves to operate reliably for over 5,000 cycles without membrane damage, with adjustable forces and pressures to maintain quality.
Implementation Method 1
the laser irradiates the welding area on the substrate through the membrane, and the welding area fuses
Implementation Method 2
the welding area fuses and then the substrate and the membrane are welded together
Implementation Method 3
pressure application means which compensates a rugged weld face of the substrate so there is no clearance and gas film between the membrane and the substrate
Implementation Method 4
a pulling force is applied to the membrane so as to tense the membrane up
Data Source
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AI summary
The present invention discloses a welding method for substrate and membrane of membrane mobile polymer microfluidic chip, which relates to the manufacturing technology of membrane mobile polymer microfluidic chip and comprises the following steps: before the welding, the substrate is fixed, the surface of the substrate is covered with the membrane; the membrane is pressed against the surface of the substrate, and in the course of welding, the laser irradiates the welding area on the substrate through the membrane, and the welding area fuses and then welds the substrate and membrane together. The present invention realizes the firm welding between membrane and substrate of membrane mobile polymer microfluidic chip, and ensures that the weld face is flat and uniform.