Micromachined Titanium Microfluidic Structures for High Pressure
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Solution Overview
Problem
Microfluidic applications, such as high-performance liquid chromatography (HPLC), face limitations in pressure handling due to the mechanical properties of typical polymer materials used in microfluidic chips, while materials like type 304 stainless steel lack effective micromachining techniques.
Innovation Solution
The use of commercially pure titanium for microfluidic structures, specifically HPLC columns, which offers superior mechanical properties and allows for advanced micromachining techniques, including diffusion bonding and electrical discharge machining, enabling higher pressure applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polymer materials are used for microfluidic structures, then ease of manufacture is improved, but pressure handling capability deteriorates
Solution Approach 1:
The patent employs titanium, a metallic material with superior mechanical properties, to replace traditional polymer materials in microfluidic structures. This material substitution resolves the contradiction by providing both high pressure handling capability and compatibility with advanced micromachining techniques, achieving a balance between structural strength and manufacturability.
2Strength
If type 304 stainless steel is used for microfluidic structures, then pressure handling capability is improved, but micromachining capability deteriorates
Solution Approach 1:
The patent selects titanium as the material, which has different physical and mechanical parameters compared to type 304 stainless steel. Titanium offers comparable or superior pressure handling capability while simultaneously providing excellent micromachinability, thus resolving the contradiction through material parameter optimization.
3Strength
If titanium is used for microfluidic structures, then pressure handling capability and micromachining capability are improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs electrical discharge machining (EDM), a non-traditional machining method that uses electrical energy instead of mechanical cutting forces, to manufacture microfluidic structures in titanium. This substitution enables precise micromachining of titanium without the limitations of conventional mechanical machining, resolving the contradiction between material strength and manufacturing complexity.
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
Titanium-based microfluidic structures can handle higher pressures and maintain fine features, enhancing the performance of HPLC columns and other microfluidic devices by providing better mechanical properties and bio-compatibility.
Implementation Method 1
Holes 105, 107, 125 and 127 are typically created using electrical discharge machining (EDM) in accordance with the invention. EDM is a technique typically used for hard metals that are electrically conductive. EDM is a nontraditional method of removing material using a series of rapidly recurring electric arcing discharges between an electrode and a work piece such as titanium sheets 110 and 120
Implementation Method 2
Like type 304 stainless steel, titanium allows diffusion bonding to create multilayer structures from sheets as thin as 1-2 mils. Titanium diffusion bonding is typically carried out at temperatures greater than about 750° C. but needs to be below the hexagonal closed packed (HCP) to body centered cubic (BCC) transition
Data Source
AI summary
In accordance with the invention, a method for making microfluidic structures in bulk titanium is disclosed. Specific microfluidic structures include HPLC structures.